Sources, pathways and fate of polychlorinated dibenzo-p-dioxins and dibenzofurans in Queensland, Australia Caroline Gaus
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- Rosa Harrington
- 5 years ago
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Transcription
1 DIOXINS IN THE MARINE ENVIRONMENT Sources, pathways and fate of polychlorinated dibenzo-p-dioxins and dibenzofurans in Queensland, Australia A t h e s i s s u b m i t t e d i n f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r t h e d e g r e e o f D o c t o r o f P h i l o s o p h y b y Caroline Gaus ( D i p l. B i o l. ) N a t i o n a l R e s e a r c h C e n t r e f o r E n v i r o n m e n t a l T o x i c o l o g y & S c h o o l o f P u b l i c H e a l t h, D e p a r t m e n t o f H e a l t h, G r i f f i t h U n i v e r s i t y, Q u e e n s l a n d, A u s t r a l i a J u l y
2 [A colour photograph reproduction that appears on this page in the print version of the thesis has been removed from the digital version for copyright reasons. The photograph shows a dugong feeding on seagrass.]
3 STATEMENT T h e w o r k p r e s e n t e d i n t h i s t h e s i s i s, t o t h e b e s t o f m y k n o w l e d g e a n d b e l i e f, o r i g i n a l, e x c e p t a s a c k n o w l e d g e d i n t h e t e x t, a n d t h e m a t e r i a l h a s n o t b e e n s u b m i t t e d, e i t h e r i n w h o l e o r i n p a r t, f o r a d e g r e e a t t h i s o r a n y o t h e r U n i v e r s i t y. S i g n e d III
4 ACKNOWLEDGEMENTS I t i s o f t e n s a i d t h a t i t i s t h e j o u r n e y t h a t c o u n t s, n o t t h e d e s t i n a t i o n. T h e p e o p l e I m e t a n d w o r k e d w i t h d u r i n g t h e l a s t t h r e e y e a r s m a d e t h i s j o u r n e y s p e c i a l. T h e y p o i n t e d t h e d i r e c t i o n, h e l p e d t o c l e a r t h e r o a d o f o b s t a c l e s o r p r o v i d e d t h e n e c e s s a r y e q u i p m e n t a n d f o o d f o r t h o u g h t. Dr. Jochen Müller a n d Prof. Des Connell g a v e m e t h e m a p t o u n d e r t a k e t h i s j o u r n e y a n d p r o v i d e d t h e r i g h t g e a r, a d v i c e a n d s o m e g r e a t o p p o r t u n i t i e s t o p r e s e n t a n d d i s c u s s m y w o r k a t i n t e r n a t i o n a l m e e t i n g s. Olaf Päpke p r o v i d e d a c c e s s t o h i s v a s t k n o w l e d g e a n d e x p e r i e n c e i n t h e w o r l d o f d i o x i n s, a n d t o t h e E R G O l a b o r a t o r i e s, w h e r e I u n d e r t o o k m o s t o f t h e a n a l y s i s. Dr. Roland Weber p l a y e d a k e y r o l e i n d e v e l o p i n g m y i d e a s o n f o r m a t i o n p r o c e s s e s d u r i n g m a n y h o u r s o f e n t h u s i a s t i c p h o n e d i s c u s s i o n s. Dr. Gregg Brunskill e n a b le d t h e w o r k o n d a t e d s e d i m e n t c o r e s b y s h a r i n g h i s w o r k a n d k n o w l e d g e. Dr. David Haynes, Dr. Wendy Blanshard a n d Dr. Bruce Hill p r o v i d e d m o s t o f t h e d u g o n g s a m p l e s, a s w e l l a s m a n y a n d m u c h a p p r e c i a t e d h o u r s o f d i s c u s s i o n s a n d i n s i g h t i n t o t h e b i o l o g y a n d e c o l o g y o f t h e a n i m a l s. Mary Hodge p r o v i d e d a c c e s s t o t h e l a b o r a t o r y a t Q u e e n s l a n d H e a l t h S c i e n t i f i c S e r v i c e s, w h e r e I a d o p t e d m e t h o d o l o g y a n d t e c h n i q u e s f r o m E R G O, w h i c h a l l o w e d t h e a n a l y s i s o f m a n y m o r e s a m p l e s t h a n w o u l d h a v e b e e n o t h e r w i s e p o s s i b l e. F i n a n c i a l s u p p o r t, p r o v i d e d b y t h e Australian Research Council, Ergo Forschungsgesellschaft a n d t h e Great Barrier Reef Marine Park Authority, a n d m y s c h o l a r s h i p, g r a n t e d b y t h e Australian Postgraduate Award (Industry) i s g r e a t l y a p p r e c i a t e d. T h e m o s t i m p o r t a n t p e r s o n i n m y l i f e n o t o n l y p r o v i d e d c o n s t a n t p e r s o n a l b u t a l s o p r o f e s s i o n a l s u p p o r t. T h a n k s Mark O Donohue f o r a l l y o u r g e n u i n e i n t e r e s t i n d i o x i n s, f o r s h a r i n g y o u r s c i e n t i f i c t a l e n t, y o u r i d e a s a n d e n t h u s i a s m f o r m y w o r k a n d v a l u a b l e i n p u t s i n t o e v e r y s i n g l e p a p e r, p r e s e n t a t i o n, g r a n t a p p l i c a t i o n, h y p o t h e s i s n u m b e r 1 t o 3 4 -C, a n d t h i s t h e s i s. T h a n k s f o r t e a c h i n g m e h o w t o g e t a r o u n d o b s t a c l e s w i t h o u t t o o m u c h d a m a g e a n d f o r l i s t e n i n g t o a n y d a m a g e r e p o r t s. T H I S T H E S I S I S F O R Y O U. W i t h o u t Joelle Prange m y d a y s w o u l d h a v e b e e n a l o t l e s s e n j o y a b l e. T h a n k s f o r t h e g r e a t d i s c u s s i o n s, f o r a l l t h e h e l p f r o m a n a l y s i s t o l a s t m i n u t e p r o o f r e a d i n g s, a n d f o r y o u r h a p p i n e s s, b o u n c i n e s s a n d t o n n e s o f c o f f e e s h a r e d. IV
5 A C K N O W L E D G E M E N T S T h a n k s t o Roland Weber f o r g e t t i n g m e t hr o u g h u n i v e r s i t y o r g a n i c c h e m i s t r y a n d m o r e t h a n a d e c a d e l a t e r f o r a n o t h e r f a n t a s t i c t e a c h i n g j o b o n t h e f o r m a t i o n a n d f i n g e r p r i n t i n g o f d i o x i n s. T h a n k s f o r y o u r c o n t i n u o u s f r i e n d s h i p, y o u r s u p p o r t a n d m o t i v a t i o n. T h a n k s t o Nigel Dennison f o r a n s w er i n g a l l m y q u e s t i o n s a n y t i m e w i t h i n c r e d i b l e p a t i e n c e a n d f o r s h o w i n g m e a l l t h e t r i c k s o f a c h e m i s t. B u t m o s t o f a l l, t h a n k s f o r y o u r f r i e n d s h i p a n d y o u r s u p p o r t i n a b s o l u t e l y e v e r y t h i n g t h a t I d i d o r p l a n n e d t o d o. T h a n k s t o Olaf Päpke f o r h i s h o s p i t a l i t y, o p e n d o o r p o l i c y d u r i n g m y s t a y s a t E R G O, o p e n p h o n e p o l i c y o n a l l t h e q u i c k q u e s t i o n s, a n d f o r t h e o p p o r t u n i t y t o l e a r n a t h i s l a b o r a t o r y. T h a n k s t o Peter Ebsen f o r t e a c h i n g m e t h e m y s t e r i e s o f H R M S a n d p e a k i d e n t i f i c a t i o n s, a n d f o r m a k i n g t h is i n t e r e s t i n g a n d f u n. T h a n k s t o t h e pesticides s e c t i o n o f Q H S S f o r m a k i n g m e f e e l p a r t o f y o u r f a n t a s t i c t e a m. I m a f r a i d t h a t a n y l a b s t h a t I w i l l c o m e a c r o s s i n t h e f u t u r e w i l l n o t b e c o m p a r a b l e. F o r h e l p w i t h t h e a n a l y s i s o r l a b o r a t o r y w o r k I t h a n k J o e l l e P r a n g e, S t e f a n H a r t k o p p, P e t e r E b s e n, K a t j a K u s c h, H o l g e r J ür g e n s o n, M a n o K r i s h n a m a n n i i, K a t i e B u n d r e d, M e l i n d a C o o k, a n d t h e Q H S S M i n i n g s e c t i o n. F o r a s s i s t a n c e i n t h e f i e l d I t h a n k D a v i d H a y n e s, J o e l l e P r a n g e, J o c h e n M ü l l e r a n d M a r k O D o n o h u e. T h a n k s a l s o t o S t e v e B e n n, t h e M o r e t o n B a y M a r i n e P a r k s, D o n n a K w a n a n d t h e Q u a n d a m o o k a c o m m u n i t y f o r p r o v i d i n g a c c e s s t o s t r a n d e d a n i m a l s i n M o r e t o n B a y a n d T o r r e s S t r a i t, a n d t o Q u e e n s l a n d P a r k s a n d W i l d l i f e S e r v i c e s i n M a r y b o r o u g h f o r c o l l e c t i n g t h e m i s s ing d a t a p o i n t s. T h a n k s f o r l a s t m i n u t e a n d l a t e n i g h t p r o o f r e a d i n g o v e r t h e l a s t f e w w e e k s t o M a r k, J o e l l e a n d J o c h e n. L a s t b u t n o t l e a s t a b i g t h a n k y o u t o m y f a m i l y f o r p r o v i d i n g t h e i r l o n g-d i s t a n c e s u p p o r t. V
6 DIOXINS IN THE MARINE ENVIRONMENT Sources, pathways and fate of polychlorinated dibenzo-p-dioxins and dibenzofurans in Queensland, Australia ABSTRACT P o l y c h l o r i n a t e d d i b e n z o -p -d i o x i n s ( P C D D s ) a n d p o l y c h l o r i n a t e d d i b e n z o f u r a n s ( P C D F s ) a r e t w o g r o u p s o f l i p o p h i l i c, p e r s i s t e n t o r g a n i c p o l l u t a n t s t h a t a r e p r o d u c e d a s b y-p r o d u c t s o f v a r i o u s a n t h r o p o g e n i c a n d i n d u s t r i a l p r o c e s s e s. D u e t o t h e i r r e l a t i v e l y h i g h t o x i c p o t e n c i e s a n d p o t e n t i a l t o b i o a c c u m u l a t e a n d b i o m a g n i f y i n o r g a n i s m s a n d t h r o u g h t h e f o o d c h a i n, t h e c o n t e m p o r a r y w i d e s p r e a d d i s t r i b u ti o n o f t h e s e c o m p o u n d s i s a c o n c e r n t o t h e h e a l t h o f t h e e n v i r o n m e n t, w i l d l i f e a n d h u m a n s. T h i s s t u d y d e t e r m i n e d t h e d i s t r i b u t i o n, p a t h w a y s a n d f a t e o f P C D D / F s i n t h e c o a s t a l z o n e o f Q u e e n s l a n d, A u s t r a l i a, i n c l u d i n g t h e i n s h o r e m a r i n e e n v i r o n m e n t o f t h e W o r l d H e r i t a g e G r e a t B a r r i e r R e e f M a r i n e P a r k. T h i s e c o s y s t e m s u p p o r t s u n i q u e f a u n a a n d f l o r a s u c h a s t h e m a r i n e h e r b i v o r o u s m a m m a l d u g o n g (D u g o n g d u g o n ) a n d i t s f o o d s o u r c e, seagrass. E l e v a t e d P C D D / F s w e r e p r e s e n t i n s o i l s a n d s e d i m e n t s a l o n g t h e e n t i r e Q u e e n s l a n d c o a s t l i n e. H i g h e s t c o n c e n t r a t i o n s w e r e f o u n d i n s o i l f r o m a g r i c u l t u r a l i r r i g a t i o n d r a i n s a n d i n s e d i m e n t s n e a r t h e m o u t h s o f m a j o r r i v e r s. E l e v a t e d c o n c e n t r a t i o n s w e r e a s s o c i a t e d w i t h r u r a l a n d u r b a n t y p e s o f l a n d -u s e, a n d P C D D / F s w e r e p r e s e n t e v e n i n l o c a t i o n s r e m o t e f r o m a n t h r o p o g e n i c a c t i v i t i e s. P C D D / F c o n g e n e r-s p e c i f i c a n a l y s i s r e v e a l e d a n u n u s u a l p r o f i l e i n a l l s a m p l e s, d o m i n a t e d b y O C D D, w i t h P C D F s p r e s e n t i n l o w c o n c e n t r a t i o n s o r b e l o w t h e l i m i t o f d e t e c t i o n. D i s t i n c t H x C D D i s o m e r p a t terns w e r e o b s e r v e d, w i t h t h e 1, 2, 3, 7, 8, 9 -H x C D D / 1, 2, 3, 4, 6, 7 -H x C D D i s o m e r p a i r d o m i n a t i n g t h e 2, 3, 7, 8 -s u b s t i t u t e d H x C D D s. S i m i l a r c o n g e n e r a n d i s o m e r c h a r a c t e r i s t i c s w e r e r e p o r t e d i n s e d i m e n t s, s o i l a n d c l a y s a m p l e s f r o m o t h e r c o n t i n e n t s, b u t c o u l d n o t b e a t t r i b u t e d t o a n y k n o w n s o u r c e. V I
7 THESIS A B S T R A C T P o s s i b l e P C D D / F s o u r c e s i n Q u e e n s l a n d w e r e a s s e s s e d u s i n g s e g m e n t e d e s t u a r i n e s e d i m e n t c o r e s, f o r w h i c h r a d i o c h e m i c a l c h r o n o l o g i e s w e r e e s t a b l i s h e d f o r e a c h d e p t h. V a r i a t i o n s o f P C D D / F c o n c e n t r a t i o n s i n t h e s e d i m e n t c o r e s o ver several centuries of d e p o s i t i o n a l h i s t o r y w e r e r e l a t i v e l y s m a l l. E l e v a t e d P C D D l e v e l s w e r e s t i l l p r e s e n t i n s e d i m e n t s l i c e s f r o m t h e e a r l y 1 7 th c e n t u r y. P C D D / F h o m o l o g u e p r o f i l e s i n s e d i m e n t s d e p o s i t e d d u r i n g t h e l a s t y e a r s w e r e a l m o s t i d e n t i c a l a n d c o r r e l a t e d w e l l t o t h e c h a r a c t e r i s t i c p r o f i l e s o b s e r v e d i n s u r f a c e s e d i m e n t s a n d s o i l s f r o m t h e e n t i r e Q u e e n s l a n d c o a s t l i n e. T h e s e r e s u l t s s u g g e s t e d t h e p r e s e n c e o f a n u n i d e n t i f i e d P C D D s o u r c e p r i o r t o t h e p r o d u c t i o n o f c o m m e r c i a l o r g a n o c h l o r i n e p r o d ucts. T o i n v e s t i g a t e t h e f o r m a t i o n o f t h e u n u s u a l P C D D / F p r o f i l e s, c o n g e n e r a n d i s o m e r s p e c i f i c a n a l y s e s w e r e u n d e r t a k e n i n s o i l s, s e d i m e n t s a n d d a t e d s e d i m e n t c o r e s. T h e r e s u l t s d e m o n s t r a t e d t h a t s p e c i f i c t r a n s f o r m a t i o n p r o c e s s e s i n t h e e n v i r o n m e n t h a v e r e s u l t e d i n t h e o b s e r v e d P C D D p r o f i l e c h a r a c t e r i s t i c s. D e c h l o r i n a t i o n o f O C D D w a s p r o p o s e d t o r e s u l t i n d i s t i n c t 1, 4 -p a t t e r n c h a r a c t e r i s t i c s ( i. e. f o r m a t i o n o f i s o m e r s c h l o r i n a t e d i n t h e 1, 4, 6, 9 -p o s i t i o n s ). C o n s e q u e n t l y, t h e e n v i r o n m e n t a l s a m p l e s d o n o t r e f l e c t t h e s i g n a t u r e s o f t h e o r i g i n a l s o u r c e. A n a l t e r n a t i v e h y p o t h e s i s t o n a t u r a l f o r m a t i o n i s d i s c u s s e d e v a l u a t i n g t h e s e p r o c e s s e s a n d t h e i r i m p l i c a t i o n s f o r p o s s i b l e s o u r c e c o n t r i b u t i o n s. T h i s h y p o t h e s i s e x p l o r e s t h e p o t e n t i a l f o r t h e i n f l u e n c e o f a n t h r o p o g e n i c P C D D p r e c u r s o r s ( e. g. p e n t a c h l o r o p h e n o l ) d u r i n g t h e s t o s. T r a n s p o r t o f P C D D / F s f r o m t h e l a n d-based source via impacted tributary river systems, a n d s u b s e q u e n t d e p o s i t i o n p r o c e s s e s a r e p r o p o s e d t o r e s u l t i n P C D D / F a c c u m u l a t i o n i n t h e i n s h o r e m a r i n e e c o s y s t e m. T h e e x t e n t o f t h e s e d i m e n t P C D D / F c o n t a m i n a t i o n g o v e r n s t h e c o n c e n t r a t i o n s i n t h e e x t e n s i v e i n s h o r e m a r i n e s e a g r a s s m e a d o w s o f Q u e e n s l a n d. P a r t i t i o n i n g p r o c e s s e s i n t h e s e d i m e n t -seagrass system lead to increased t o x i c e q u i v a l e n cy ( T E Q ) i n t h e s e a g r a s s, c o m p a r e d t o s e d i m e n t. T h e r e l a t i o n s h i p b e t w e e n c o n t a m i n a t e d i n s h o r e s e d i m e n t s, s e a g r a s s a n d d u g o n g s w e r e e v a l u a t e d u s i n g s i x d u g o n g h a b i t a t r e g i o n s a l o n g t h e c o a s t l i n e. P C D D / F b o d y b u r d e n s i n d u g o n g s a r e g o v e r n e d b y s e d i m e n t ( a n d s e a g r a s s ) P C D D / F c o n c e n t r a t i o n s i n t h e i r h a b i t a t. H i g h s e a g r a s s ( a n d i n c i d e n t a l s e d i m e n t ) i n g e s t i o n r a t e s, s e l e c t i v e r e t e n t i o n o f t o x i c o l o g i c a l l y p o t e n t c o n g e n e r s a n d r e l a t i v e l y l o w P C D D / F e l i m i n a t i o n c a p a c i t i e s i n d u g o n g s a r e p r o p o s e d t o r e s u l t i n e l e v a t e d P C D D / F c o n c e n t r a t i o n s a n d T E Q l e v e l s i n VII
8 THESIS A B S T R A C T a d u l t a n i m a l s. T r a n s f e r e f f i c i e n c i e s o f 4 a n d 2 7 % o f m a t e r n a l T E Q l e v e l s t o f o e t u s e s a n d c a l v e s ( r e s p e c t i v e l y ) d u r i n g g e s t a t i o n a n d l a c t a t i o n r e s u l t i n r e l a t i v e l y h i g h e x p o s u r e p o t e n t i a l s t o o f f s p r i n g. C o m p a r e d t o n o -observed -adverse-e f f e c t -l e v e l s i n o t h e r m a m m a l s, a n d b a s e d o n t h e r e s u l t s o f t h i s s t u d y, a t o l e r a b l e d a i l y i n t a k e ( T D I ) o f p g T E Q k g -1 d a y -1 w a s e s t i m a t e d f o r d u g o n g s. T h e r e s u l t s o f t h e p r e s e n t s t u d y f o u n d t h a t d u g o n g s f r o m s o m e r e g i o n s a l o n g t h e c o a s t l i n e o f Q u e e n s l a n d e x c e e d t h i s T D I b y u p t o 2 0 f o l d, s u g g e s t i n g t h a t t h e s e p o p u l a t i o n s m a y b e a t r i s k f r o m P C D D / F c o n t a m i n a t i o n i n t h e i r h a b i t a t. T h e s e r e s u l t s h a v e i m p o r t a n t i m p l i c a t i o n s f o r t h e h e a l t h o f t h e e n v i r o n m e n t, w i l d l i f e a n d h u m a n s a n d w e r e u s e d t o d e v e l o p a c o n c e p t u a l u n d e r s t a n d i n g o f t h e s o u r c e s, p a t h w a y s a n d f a t e o f d i o x i n s i n Q u e e n s l a n d, A u s t r a l i a. VIII
9 TABLE OF CONTENTS DIOXINS IN THE MARINE ENVIRONMENT - SOURCES, PATHWAYS AND FATE OF POLYCHLORINATED DIBENZO- P-DIOXINS AND DIBENZOFURANS IN QUEENSLAND, AUSTRALIA STATEMENT III A C K N O W L E D G E M E N T S IV A BSTRACT V I T ABLE OF CONTENTS IX FIGURES X I II T ABLES X V I A B B R E V I A T I O N S A N D D E FINITIONS XVIII CHAPTER 1 GENERAL INTRODUCTION AND THESIS OUTLINE - DIOXINS IN THE MARINE ENVIRONMENT SOURCES, PATHWAYS AND FATE OF PCDD/FS IN QUEENSLAND, AUSTRALIA 19 CHAPTER 2 SPATIAL DISTRIBUTION OF PCDD/FS IN QUEENSLAND - EVIDENCE FOR THE PRESENCE OF A WIDESPREAD SOURCE 27 ABSTRACT INTRODUCTION MATERIALS AND METHODS S a m p l i n g A n a l y s i s O r g a n i c c a r b o n RESULTS AND DISCUSSION R e p r o d u c i b i l i t y M a r i n e s e d i m e n t s T e r r e s t r i a l t o p s o i l a n d i r r i g a t i o n d r a i n s e d i m e n t s S o u r c e s CONCLUSIONS 40 CHAPTER 3 TEMPORAL PCDD/F DISTRIBUTION IN QUEENSLAND - NATURAL FORMATION? 44 ABSTRACT INTRODUCTION MATERIALS AND METHODS L o c a t i o n d e s c r i p t i o n 4 8 IX
10 T ABLE OF C O N T E N T S S a m p l i n g S e d i m e n t c o r e c h r o n o l o g i e s P C D D / F a n a l y s i s Q u a l i t y c o n t r o l O r g a n i c c a r b o n RESULTS P h y s i c a l p a r a m e t e r s Q u a l i t y c o n t r o l T e m p o r a l P C D D / F d i s t r i b u t i o n , 3, 7, 8 -P C D D / F c o n g e n e r p r o f i l e s a n d i s o m e r p a t t e r n s DISCUSSION H i s t o r i c a l a n t h r o p o g e n i c i n p u t s i g n i f i c a n c e N a t u r a l s o u r c e s 5 9 CHAPTER 4 TRANSFORMATION OF PCDD/FS IN ENVIRONMENTAL SINKS - FORMATION OF THE DISTINCT 1,4-PATTERN 63 ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION P C D D / F f i n g e r p r i n t s T r a n s f o r m a t i o n o f P C D D / F s i g n a t u r e s D e c h l o r i n a t i o n P a t h w a y s 6 9 CHAPTER 5 AN ALTERNATIVE HYPOTHESIS TO NATURAL PCDD FORMATION - INDICATIONS FOR ANTHROPOGENIC FORMATION 77 ABSTRACT INTRODUCTION RESULTS AND DISCUSSION G l o b a l p a t t e r n s N a t u r a l S o u r c e S c e n a r i o A n t h r o p o g e n i c S o u r c e S c e n a r i o P C D D / F p a t t e r n s i n P C P c o n t a m i n a t e d e n v i r o n m e n t s P C P A p p l i c a t i o n i n A u s t r a l i a 87 CHAPTER 6 FATE OF DIOXINS - CONTAMINATION OF THE INSHORE SEDIMENT-SEAGRASS-DUGONG SYSTEM 90 ABSTRACT INTRODUCTION MATERIALS AND METHODS 94 X
11 T ABLE OF C O N T E N T S S a m p l i n g B i o t a a n a l y s i s S e d i m e n t a n al y s i s Q u a l i t y c o n t r o l D a t a a n a l y s i s Paramete r s u s e d f o r m o d e l l i n g RESULTS AND DISCUSSION Q u a l i t y c o n t r o l P C D D / F c o n c e n t r a t i o n s a n d T E Q s i n d u g o n g s P C D D / F t r a n s p o r t a n d e x p o s u r e p a t h w a y s R e g i o n a l e x p o su r e o f d u g o n g s P C D D / F r e t e n t i o n A b s o r p t i o n a n d e l i m i n a t i o n c a p a c i t i e s N o n -2, 3, 7, 8 s u b s t i t u t e d P C D D / F s P C D D / F t r a n s f e r t o o f f s p r i n g I m p l i c a t i o n s a n d e s t i m a t i o n o f p o t e n t i a l r i s k s CHAPTER 7 DIOXINS IN QUEENSLAND, AUSTRALIA - KEY FINDINGS, IMPLICATIONS AND FUTURE RESEARCH CONCEPTUAL MODEL S o u r c e a n d f o r m a t i o n P a t h w a y s a n d p r o c e s s e s S p a t i a l d i s t r i b u t i o n T r a n s p o r t t o t h e m a r i n e e n v i r o n m e n t T r a n s f o r m a t i o n i n t h e m a r i n e e n v i r o n m e n t F a t e o f d i o x i n s i n t h e n e a r s h o r e m a r i n e s y s t e m R e d i s t r i b u t i o n f r o m m a r i n e s e d i m e n t s P C D D / F r e t e n t i o n i n d u g o n g s T r a n s f e r IMPLICATIONS FOR THE ENVIRONMENT, HUMANS AND WILDLIFE P C D D / F c o n c e n t r a t i o n s i n Q u e e n s l a n d s e n v i ro n m e n t E x p o s u r e t o P C D D / F s W i l d l i f e H u m a n s TOOLS FOR RISK ASSESSMENT FUTURE RESEARCH 136 BIBLIOGRAPHY 139 X I
12 T ABLE OF C O N T E N T S FIGURES FIGURE 2.1 M a p o f Q u e e n s l a n d, A u s t r a l i a s h o w i n g s a m p l i n g s i t e s, a p p r o x i m a t e l o c a t i o n s o f s u g a r c a n e a n d c o t t o n g r o w i n g a r e a s, a s w e l l a s m a j o r urban centers 3 3 FIGURE 2.2 O C D D c o n c e n t r a t i o n s ( n g g -1 T O C a n d p g g - 1 d w ) i n m a r i n e s e d i m e n t s from Queensland. 3 6 FIGURE 2.3 O C D D c o n c e n t r a t i o n s ( n g g - 1 T o c a n d p g g - 1 d w ) i n t o p s o i l f r o m Queensland. 3 7 FIGURE 2.4 O C D D c o n c e n t r a t i o n s ( n g g - 1 T O C a n d p g g - 1 d w ) i n i r r i g a t i o n d r a i n sediments from Queensland. 3 8 FIGURE 2.5 T y p i c a l P C D D / F c o n g e n e r p r o f i l e i n m a r i n e s e d i m e n t s a n d t o p s o i l from Queensland. 3 9 FIGURE 2.6 H e x a-c D D i s o m e r p a t t e r n f r o m a t y p i c a l s a m p l e f r o m Q u e e n s l a n d ( A ), kaolinite clay (B) and pentachlorophenol (C). 4 2 FIGURE 3.1 M a p o f Q u e e n s l a n d, A u s t r a l i a a n d s i t e s o f s e d i m e n t c o r e s c o l l e c t e d f r o m A. H i n c h i n b r o o k a r e a (c o r e ) a n d B. B u r d e k i n a r e a ( c o r e 1260). 5 0 FIGURE 3.2 V e r t i c a l d i s t r i b u t i o n o f Σ PCDD/F (pg g-1 d w ) a n d O C D D ( p g g-1 d w ) c o n c e n t r a t i o n s i n H i n c h i n b r o o k c o r e a n d B u r d e k i n c o r e versu s t h e e s t i m a t e d y e a r o f s e d i m e n t a t i o n ( d e r i v e d f r o m e x c e s s P b a n d C s p r o f i l e s ). S t a n d a r d d e v i a t i o n s i n d i c a t e t h e v a r i a t i o n s f r o m replicate analysis 5 4 FIGURE 3.3 2, 3, 7, 8 -P C D D / F c o n g e n e r p r o f i l e i n m a r i n e s e d i m e n t c o r e s f r o m Q u e e n s l a n d, A u s t r a l i a. S t a n d a r d d e v i a t i o n s i n d i c a t e t h e v a r i a t i o n among all samples from both cores. 5 7 FIGURE 4.1 Isomer patterns of tetra - t o h e p t a c h l o r i n a t e d P C D D s ( u s i n g a D B-5 c o l u m n ) i n A. H i n c h i n b r o o k c o r e s e d i m e n t s f r o m t h e s u r f a c e l a y e r s ( r e c e n t l y d e p o s i t e d ) a n d B. f r o m t h e b o t t o m l a y e r ( d e p o s i t e d a p p r o x i m a t e l y y e a r s a g o ). T h e x -a x i s r e p r e s e n t s t h e % XII
13 T ABLE OF C O N T E N T S c o n t r i b u t i o n, t h e y -a x i s r e p r e s e n t s t h e r e l a t i v e r e t e n t i o n t i m e s o f t h e isomers (omitted). 6 9 FIGURE 4.2 I s o m e r d i s t r i b u t i o n o f t e t r a - t o h e p t a c h l o r i n a t e d P C D D s i n. Q u e e n s l a n d s e d i m e n t c o r e s, a n d r i v e r s a m p l e s f r o m t h e H i n c h i n b r o o k a r e a. W h i t e a r r o w s i n d i c a t e t h e p a t h w a y o f l a t e r a l d e c h l o r i n a t i o n ; b l a c k a r r o w s i n d i c a t e t h e i s o m e r s r e s u l t i n g f r o m l a t e r a l - (L), peri -l a t e r a l - (LP) and peri - ( P ) d e c h l o r i n a t i o n f r o m O C D D. N o t e : 1, 2, 3, 4, 6, 8 -H x C D D w a s c o -e l u t e d i n O s a k a B a y c o r e s e d i m e n t s w i t h 1, 2, 4, 6, 7, 9 / 1, 2, 4, 6, 8, 9 - HxCDD 7 0 FIGURE 4.3 R e l a t i v e i n c r e a s e ( c o n t r i b u t i o n o f Σ h o m o l o g u e g r o u p - t o Σ P C D D c o n c e n t r a t i o n s ) o f t e t r a - t o h e p t a c h l o r i n a t e d P C D D s a n d r e l a t i v e d e c r e a s e o f O C D D w i t h i nc r e a s i n g s e d i m e n t a t i o n a g e i n B u r d e k i n a n d H i n c h i n b r o o k c o r e s e d i m e n t s a n d w i t h i n t h e s h a d e d a r e a - i n t o p s o i l and surface river sediments from the Hinchinbrook area. 7 1 FIGURE 4.4 E s t i m a t e d ti m e o f d i s a p p e a r a n c e o f O C D D a n d t i m e o f a p p e a r a n c e o f l o w e r c h l o r i n a t e d P C D D s u s i n g t h e s l o p e s o b t a i n e d f r o m t h e r e l a t i v e d e c r e a s e o f O C D D a n d r e l a t i v e d e c r e a s e o f l o w e r c h l o r i n a t e d t e t r a - t o h e p t a c h l o r i n a t e d P C D D s w i t h i n c r e a s i n g s e d i m e n t a t i o n a g e i n Burd e k i n a n d H i n c h i n b r o o k c o r e s e d i m e n t s ( s e e F i g u r e 2 ), a s s u m i n g t h e f o r m a t i o n o f P C D D s a t t h e t i m e o f s e d i m e n t a t i o n ( i. e y e a r s until present). 7 2 FIGURE 5.1 I s o m e r d i s t r i b u t i o n o f t e t r a - t o h e p t a c h l o r i n a t e d P C D D s i n A. Q u e e n s l a n d s e d i m e n t c o r e s a n d r i v e r s a m p l e s f r o m t h e H i n c h i n b r o o k a r e a a n d B. K a s u m i g a u r a L a k e s e d i m e n t s ( S a k u r a i e t a l ), M i s s i s s i p p i R i v e r s e d i m e n t s ( R a p p e e t a l a ), G e r m a n k a o l i n i t e c l a y ( P ä p k e ), O s a k a B a y c o re s e d i m e n t ( H a s h i m o t o e t a l ) a n d H o n g K o n g c o r e s e d i m e n t s. ( N o t e t h a t s o m e i s o m e r s c o u l d n o t b e o b t a i n e d f r o m t h e l i t e r a t u r e ). W h i t e a r r o w s i n d i c a t e t h e p a t h w a y o f l a t e r a l d e c h l o r i n a t i o n ; b l a c k a r r o w s i n d i c a t e t h e i s o m e r s r e s u l t i n g f r o m l a t e r a l - (L), p e r i -l a t e r a l - (LP) and peri- ( P ) d e c h l o r i n a t i o n f r o m O C D D. N o t e : 1, 2, 3, 4, 6, 8 -H x C D D w a s c o -e l u t e d i n O s a k a B a y c o r e s e d i m e n t s with 1,2,4,6,7,9/1,2,4,6,8,9 -HxCDD. 8 3 XIII
14 T ABLE OF C O N T E N T S FIGURE 5.2 S c h e m a t i c o f d ec h l o r i n a t i o n p r o c e s s e s o f h i g h e r c h l o r i n a t e d P C D D s a n d t h e r e s u l t a n t p r o d u c t i o n o f l o w e r c h l o r i n a t e d P C D D s w i t h t i m e o f d e p o s i t i o n i n t h e s e d i m e n t e n v i r o n m e n t t o r e s u l t i n t h e h o m o l o g u e s h i f t o b s e r v e d i n t h e s e d i m e n t c o r e s. S c e n a r i o A p o s t u l a t e s t h e d e p o si t i o n o f m a i n l y h i g h e r c h l o r i n a t e d P C D D s o n l a n d, t h e i r s u b s e q u e n t t r a n s p o r t a n d d e c h l o r i n a t i o n i n t h e m a r i n e e n v i r o n m e n t. S c e n a r i o B p o s t u l a t e s t h e d e p o s i t i o n o f a n t h r o p o g e n i c C P s ( a n d t h e i r d e r i v a t i v e s ) d u r i n g t h e m i d 2 0 t h c e n t u r y, t h e i r t r a n s p o r t a n d mi g r a t i o n i n t o d e e p s e d i m e n t l a y e r s, a n d s u b s e q u e n t f o r m a t i o n a n d d e c h l o r i n a t i o n o f OCDD in the marine environment. 8 6 FIGURE 5.3 E s t i m a t e d t i m e o f d i s a p p e a r a n c e o f O C D D a n d t i m e o f a p p e a r a n c e o f l o w e r c h l o r i n a t e d P C D D s u s i n g t h e s l o p e s o b t a i n e d f r o m t h e r e l a t i v e d e c r e a s e o f O C D D a n d r e l a t i v e d e c r e a s e o f l o w e r c h l o r i n a t e d t e t r a - t o h e p t a c h l o r i n a t e d P C D D s w i t h i n c r e a s i n g s e d i m e n t a t i o n a g e i n B u r d e k i n a n d H i n c h i n b r o o k c o r e s e d i m e n t s ( s e e C h a p t e r 4 ), assuming the formation of PCDDs 40 years from present. 8 7 FIGURE 6.1 M a p o f Q u e e n s l a n d, A u s t r a l i a s h o w i n g t h e s i x d u g o n g s t r a n d i n g r e g i o n s a l o n g t h e Q u e e n s l a n d c o a s t l i n e. S u b s e t m a p s s h o w t h e s e d i m e n t s a m p l i n g s i t e s i n e a c h r e g i o n w i t h i n t h e d u g o n g h a b i t a t s ( i. e. s e a g r a s s o c c u r r e n c e ) a n d m a j o r r i v e r s y s t e m s. M a p s w e r e p r o d u c e d u s i n g G I S d a t a p r o v i d e d b y t h e D e p a r t m e n t o f P r i m a r y I n d u s t r i e s, FIGURE 6.2 D e c r e a s e o f s e d i m e n t O C D D c o n c e n t r a t i o n w i t h i n c r e a s i n g d i s t a n c e f r o m r i v e r m o u t h s a l o n g f i v e s e p a r a t e w e s t -e a s t t r a n s e c t s a l o n g t h e Queensland coastline FIGURE 6.3 C o r r e l a t i o n b e t w e e n t h e r e l a t i v e a c c u m u l a t i o n e f f i c i e n c i e s ( b i o a c c u m u l a t i o n f a c t o r s, B F ) o f P C D D / F c o n g e n e r s a n d h o m o l o g u e s i n s e a g r a s s f r o m s e d i m e n t t o t h e l o g K o w. Average K ow o f t h e r e s p e c t i v e c o n g e n e r s h a v e b e e n u s e d f o r t h e h o m o l o g u e g r o u p s t o e xemplify the similar accumulation efficiencies FIGURE 6.4 C o r r e l a t i o n b e t w e e n P C D D / F b o d y b u r d e n i n a d u l t m a l e, a d u l t f e m a l e a n d i m m a t u r e ( c a l f ) d u g o n g s a n d O C D D c o n c e n t r a t i o n i n s e d i m e n t s XIV
15 T ABLE OF C O N T E N T S f r o m R e g i o n 1 t o 6. E r r o r b a r s r e p r e s e n t s t a n d a r d d e v i a t i o n s a n d 9 5 percentiles are given above and below the calculated mean FIGURE 6.5 B i o a c c u m u l a t i o n F a c t o r s ( B F ) o f 2, 3, 7, 8 -s u b s t i t u t e d P C D D / F s i n a d u l t male dugongs from sediment and seagrass FIGURE 6.6 C h a n g e i n % c o n t r i b u t i o n o f 2, 3, 7, 8 -s u b s t i t u t e d P C D D c o n g e n e r s i n d u g o n g s r e l a t i v e t o t h a t i n s e d i m e n t s w i t h i n c r e a s i n g O C D D s e d i m e n t concentraton FIGURE 6.7 P C D D c o n g e n e r d i s t r i b u t i o n i n s e d i m e n t s a n d a d u l t d u g o n g s f r o m Hervey Bay FIGURE 6.8 P C D F c o n g e n e r d i s t r i b u t i o n i n s e d i m e n t s a n d a d u l t d u g o n g s f r o m Hervey Bay FIGURE 6.9 T r a n s f e r f a c t o r ( T F ) o f 2, 3, 7, 8 -s u b s t i t u t e d a n d n o n-2, 3, 7, 8 -s u b s t i t u t e d PCDD/Fs from dugong mothers to calves and foetuses FIGURE 7.1 C o n c e p t u a l m o d e l o f s o u r c e s ( i n c l. p r e c u r s o r h y p o t h e s i s ), t r a n s p o r t p a t h w a y s a n d p r o c e s s e s t o a n d w i t h i n t h e m a r i n e s y s t e m o f Queensland, Australia FIGURE 7.2 E s t i m a t e d P C D D / F l o a d s i n t h e e n v i r o n m e n t a l c o m p a r t m e n t s s o i l, s e d i m e n t, s e a g r a s s a n d d u g o n g f r o m t h e c o a s t a l z o n e o f Q u e e n s l a n d, A u s t r a l i a. S u b s e t s h o w s t h e c o m p a r t m e n t s s o i l a n d s e d i m e n t o n l y. Both y-axes represent natural logarithm scales X V
16 T ABLE OF C O N T E N T S TABLES TABLE 2.1 C o n c e n t r a t i o n s o f 2, 3, 7, 8 -s u b s t i t u t e d P C D D / F s a n d s u m o f i s o m e r s i n h o m o l o gu e s ( i n n g g - 1 T O C ( l e f t c o l u m n s ) a n d p g g - 1 dw (right columns)) and % TOC for marine sediments and topsoil samples. 4 1 TABLE 3.1 C o n c e n t r a t i o n o f P C D D / F h o m o l o g u e s a n d 2, 3, 7, 8 -s u b s t i t u t e d conge n e r s ( i n p g g -1 d w ) i n m a r i n e s e d i m e n t c o r e s f r o m ( H i n c h i n b r o o k ) T o t a l o r g a n i c c a r b o n ( % T O C ) i s g i v e n f o r e a c h c o r e slice analysed. 5 5 TABLE 3.2 C o n c e n t r a t i o n o f P C D D / F h o m o l o g u e s a n d 2, 3, 7, 8 -s u b s t i t u t e d c o n g e n e r s ( i n p g g -1 d w ) i n m a r i n e s e d i m e n t c o r e s f r o m ( B u r d e k i n ) T o t a l o r g a n i c c a r b o n ( % T O C ) i s g i v e n f o r e a c h c o r e s l i c e analysed. 5 6 TABLE 4.1 R a t i o s o f l a t e r a l d e c h l o r i n a t e d ( L ) a n d p e r i d e c h l o r i n a t e d ( P ) H p C D D s ( i. e. 1, 2, 3, 4, 6, 7, 9 -H p C D D : 1, 2, 3, 4, 6, 7, 8 -HpCDD) and L : LP : P H x C D D s ( i. e. 1, 2, 4, 6, 7, 9 / 1, 2, 4, 6, 8, 9 -H x C D D : 1, 2, 3, 6, 7, 9 -/ 1, 2, 3, 6, 8, 9 - H x C D D : 1, 2, 3, 6, 7, 8 -/ 1, 2, 3, 7, 8, 9 -/ 1, 2, 3, 4, 6, 7 -H x C D D ) a n d % c o n t r i b u t i o n o f L P n C D D ( i. e. 1, 2, 4, 6, 9 -P n C D D ) a n d L T C D D ( i. e. 1, 4, 6, 9 -T C D D ) t o t h e Σ h o m o l o g u e g r o u p i n a r a n g e o f s a m p l e s f r o m Queensland and elsewhere. 7 4 TABLE 5.1 R a t i o s o f l a t e r a l d e c h l o r i n a t e d ( L ) a n d p e ri d e c h l o r i n a t e d ( P ) H p C D D s ( i. e. 1, 2, 3, 4, 6, 7, 9 -H p C D D : 1, 2, 3, 4, 6, 7, 8 -HpCDD) and L : LP : P H x C D D s ( i. e. 1, 2, 4, 6, 7, 9 / 1, 2, 4, 6, 8, 9 -H x C D D : 1, 2, 3, 6, 7, 9 -/ 1, 2, 3, 6, 8, 9 - H x C D D : 1, 2, 3, 6, 7, 8 -/ 1, 2, 3, 7, 8, 9 -/ 1, 2, 3, 4, 6, 7 -H x C D D ) a n d % c o n t r i b u t i o n o f L P n C D D ( i. e. 1, 2, 4, 6, 9 -P n C D D ) a n d L T C D D ( i. e. 1, 4, 6, 9 -T C D D ) t o t h e Σ h o m o l o g u e g r o u p i n a r a n g e o f s a m p l e s f r o m Queensland and elsewhere. 8 9 TABLE 6.1 Average (bold) and range PCDD/F concentrations (pg g -1 l i p i d ) i n a d u l t m a l e ( A, M ) a n d a d u l t f e m a l e ( A, F ) d u g o n g s a s w e l l a s c a l v e s ( C ) a n d f o e t u s e s ( F ) f r o m s i x d i f f e r e n t h a b i t a t r e g i o n s a l o n g t h e Q u e e n s l a n d c o a s t l i n e. T E Q s w e r e c a l c u l a t e d u s i n g W H O T E F s ( V a n d e n B e r g e t al. 1998). n.d.: not detected; n.a.: not available; > not quantifiable X V I
17 T ABLE OF C O N T E N T S TABLE 6.2 P C D D / F c o n c e n t r a t i o n s i n s e d i m e n t s a n d s e a g r a s s f r o m t h r e e d i f f e r e n t d u g o n g h a b i t a t r e g i o n s i n Q u e e n s l a n d. A v e r a g e s a r e g i v e n w h e n s a m p l e s f r o m t h e s a m e s i t e h a v e b e e n a n a l y s e d i n r e p l i c a t e. T E Q s were calculated using the WHO TEF (Van den Berg et al. 1998) XVII
18 ABBREVIATIONS AND DEFINITIONS P O P P e r s i s t e n t o r g a n i c p o l l u t a n t ; e. g. P C D D / F s, P C B s, D D T, H e x a c h l o r o b e n z e n e, M i r e x, T o x a p h e n e, A l d r i n, D i e l d r i n, E n d r i n, C h l o r d a n e, H e p t a c h l o r D i o x i n s G e n e r a l t e r m u s e d h e r e t o i n c l u d e P C D D s a n d P C D F s P C D D s P o l y c h l o r i n a t e d d i b e n z o -p-d i o x i n s PCDFs P o l y c h l o r i n a t e d d i b e n z o f u r a n s T C D D / F T e t r a c h l o r o d i b e n z o d i o x i n / f u r a n P n C D D / F P e n t a c h lo r o d i b e n z o d i o x i n / f u r a n H x C D D / F H e x a c h l o r o d i b e n z o d i o x i n / f u r a n H p C D D / F H e p t a c h l o r o d i b e n z o d i o x i n / f u r a n O C D D / F O c t a c h l o r o d i b e n z o d i o x i n / f u r a n C o n g e n e r C o m p o u n d m e m b e r o f t h e s a m e c h e m i c a l f a m i l y ; e. g. t h e r e a r e 7 5 P C D D c o n g e n e r s H o m o l o g u e G r o u p o f s t r u c t ur a l l y r e l a t e d c h e m i c a l s t h a t h a v e t h e s a m e d e g r e e o f c h l o r i n a t i o n ; e. g. t h e r e a r e 8 P C D D h o m o l o g u e s I s o m e r S u b s t a n c e t h a t b e l o n g t o t h e s a m e h o m o l o g u e c l a s s ; e. g. t h e r e a r e 2 2 i s o m e r s i n t h e h o m o l o g u e g r o u p T C D D 2, 3, 7, 8 - s u b s t i t u t e d P C D D / F c o n g e n e r s w i t h c h l o r i n e s u b s t i t u e n t s i n t h e 2, 3, 7, a n d 8 p o s i t i o n P C D D / F s K ow O c t a n o l-w a t e r p a r t i t i o n c o e f f i c i e n t TEF W H O T o x i c e q u i v a l e n c y f a c t o r, t o x i c i t y o f a c o m p o u n d r e l a t i v e t o t h a t o f 2, 3, 7, 8 -T C D D ( V a n d e n B e r g e t a l ) TEQ T o x i c e q u i v a l e n c y d e f i n e d a s t h e c o n c e n t r a t i o n o f a c o m p o u n d m u l t i p l i e d b y i t s t o x i c e q u i v a l e n c y f a c t o r ( T E F ) ( V a n d e n B e r g e t a l ) A D I A v e r a g e d a i l y i n t a k e T D I T o l e r a b l e d a i l y i n t a k e N O A E L N o o b s e r v e d a d v e r s e e f f e c t l e v e l LOAEL L o w e s t o b s e r v e d a d v e r s e e f f e c t l e v e l XVIII
19 CHAPTER 1 GENERAL INTRODUCTION AND THESIS OUTLINE Dioxins in the marine environment sources, pathways and fate of PCDD/Fs in Queensland, Australia
20 C H A P T E R 1 IN T R O D U C T I O N P o l y c h l o r i n a t e d d i b e n z o -p -d i o x i n s ( P C D D s ) a n d p o l y c h l o r i n a t e d d i b e n z o f u r a n s ( P C D F s ) a r e t w o g r o u p s o f p e r s i s t e n t o r g a n i c p o l l u t a n t s ( P O P s ), c o m p r i s i n g a t o t a l o f c o m p o u n d s, 7 5 P C D D a n d P C D F c o n g e n e r s a n d a r e o f t e n s i m p l y r e f e r r e d t o a s d i o x i n s. T h e s e c o m p o u n d s a r e h i g h l y p e r s i s t e n t, h y d r o p h o b i c a n d s e m i v o l a t i l e, r e s u l t i n g i n t h e i r u b i q u i t o u s d i s t r i b u t i o n i n t h e e n vi r o n m e n t a n d b i o a c c u m u l a t i o n i n o r g a n i c m a t r i c e s, i n c l u d i n g t h e t i s s u e s o f o r g a n i s m s ( V a n d e n B e r g e t a l ; B a k e r a n d H i t e s ). T h e s e c h a r a c t e r i s t i c s, t o g e t h e r w i t h a r e l a t i v e l y h i g h t o x i c i t y t o o r g a n i s m s, r e p r e s e n t a s e r i o u s c o n c e r n w i t h r e s p e c t t o t h e h e a l t h o f t h e e n v i r o n m e n t, w i l d l i f e a n d h u m a n s ( W H O ; U. S. E P A ). T o x i c r e s p o n s e s e l i c i t e d b y P C D D / F s i n c l u d e i m m u n o t o x i c i t y, c a r c i n o g e n i c i t y, d e r m a l t o x i c i t y a n d a d v e r s e e f f e c t s o n r e p r o d u c t i o n, d e v e l o p m e n t, a n d e n d o c r i n e f u n c t i o n s ( V a n d e n B e r g ). P C D D / F s a n d o t h e r d i o x i n -l i k e c o m p o u n d s a r e s u b j e c t t o g l o b a l c o n v e n t i o n s, a n d c o u n t r i e s, i n c l u d i n g A u s t r a l i a, s i g n e d a l e g a l l y b i n d i n g t r e a t y i n ( S t o c k h o l m C o n v e n t i o n ), t o r e d u c e a n d w h e r e f e a s i b l e e l i m i n a t e d e f i n e d P O P s s u c h a s P C D D s a n d PCDFs ( U N E P ). H i s t o r i c a l l y, t h e m a j o r i t y o f P O P s h a v e b e e n u s e d a n d e m i t t e d i n t h e i n d u s t r i a l i s e d r e g i o n s o f t h e n o r t h e r n t e m p e r a t e e n v i r o n m e n t ( W a n i a a n d M a c k a y ). For e x a m p l e, i n t h e m a j o r i t y o f P C D D / F e m i s s i o n w a s e m i t t e d f r o m t h e E u r o p e a n U n i o n, J a p a n a n d U. S. A ( U N E P ). I t i s e s t i m a t e d t h a t a t o t a l o f a p p r o x i m a t e l y (± ) k g P C D D / F s a r e e m i t t e d p e r a n n u m t o t h e e n v i r o n m e n t (Brzuzy an d H i t e s ). I n v e n t o r i e s o n t h e v a r i o u s s o u r c e s o f P C D D / F s h a v e b e e n c o n d u c t e d i n m a n y i n d u s t r i a l i s e d c o u n t r i e s ( E d u l j e e a n d D y k e ; C l e v e r l y e t a l ; Q u a s s e t a l ; A l c o c k e t a l ; H a r r a d a n d J o n e s ; H o l o u b e k e t a l ; C l e v e r l y, S c h a u m ), a s w e l l a s o n a g l o b a l s c a l e ( B r z u z y a n d H i t e s ). T h e m a j o r i t y o f t h e s e s t u d i e s f o u n d t h a t t o d a y s m a j o r e m i s s i o n s o f P C D D / F s r e s u l t f r o m c o m b u s t i o n p r o c e s s e s ( C z u c z w a a n d H i t e s ), c o n t r i b u t i n g a p p r o x i m a t e l y 5 0 % t o t h e g l o b a l i n v e n t o r y ( U N E P ). O t h e r i m p o r t a n t s o u r c e s i n c l u d e i n d u s t r i a l -c h e m i c a l p r o c e s s e s, a p p l i c a t i o n o f p e s t i c i d e s, a n d r e s e r v o i r o r s o -c a l l e d s e c o n d a r y s o u r c es (e.g. s e w a g e s l u d g e ), w h e r e P C D D / F s h a v e b e e n a c c u m u l a t e d a n d c a n b e r e d i s t r i b u t e d t o t h e e n v i r o n m e n t ( U N E P ; D y k e e t a l ). H o w e v e r, w h i l e k e y p o l l u t a n t s o u r c e s a r e t h o u g h t t o b e i d e n t i f i e d i n m a n y c o u n t r i e s, l o c a l a n d g l o b a l P C D D / F s o u r c e e m i s s i o n e s t i m a t e s a r e n o t i n b a l a n c e ( b o t h i n t e r m s o f c o m p o s i t i o n a n d c o n c e n t r a t i o n ) w i t h t h e i r e n v i r o n m e n t a l d e p o s i t i o n (Brzuzy a n d H i t e s ; B r u b a k e r a n d H i t e s ; E i s e n b e r g e t a l ; B a k e r a n d H i t e s ; T h o m a s a n d S p i r o ). S u c h m a s s a n d 2 0
21 C H A P T E R 1 IN T R O D U C T I O N c o m p o s i t i o n i m b a l a n c e s h a v e b e e n a t t r i b u t e d t o ( i ) u n d e r e s t i m a t e d o r u n i d e n t i f i e d c o n t r i b u t i o n s f r o m a n t h r o p o g e n i c a n d n a t u r a l P C D D / F s o u r c e s ( B r z u z y a n d H i t e s ; G r i b b l e ) o r ( i i ) s y n t h e s i s f r o m p r e c u r s o r s i n t h e e n v i r o n m e n t a n d i n a d e q u a t e l y u n d e r s t o o d t r a n s f o r m a t i o n p r o c e s s e s o f P C D D / F s a l o n g t h e i r t r a n s p o r t p a t h w a y s (Baker a n d H i t e s ; B r u b a k e r a n d H i t e s ). D u r i n g t r a n s p o r t, P O P s p a r t i t i o n b e t w e e n g a s e o u s, l i q u i d a n d p a r t i c l e p h a s e s, f a c i l i t a t i n g t h e i r c y c l i n g b e t w e e n t h e e n v i r o n m e n t a l c o m p a r t m e n t s o f a i r, s o i l, w a t e r, a n d b i o t a ( C o n n e l l a n d H a w k e r ; C o n n e l l ; W a n i a a n d M a c k a y ). The e n v i r o n m e n t a l f a t e a n d p a t h w a y s o f t h e c o m p o u n d s a r e s t r o n g l y d e p e n d e n t o n t h e i r p h y s i c o -c h e m i c a l p r o p e r t i e s ( W a n i a ; H u t z i n g e r e t a l ; T y s k l i n d e t a l ; H a g e n m a i e r e t a l ). V o l a t i l i s a t i o n, w e t a n d d r y d e p o s i t i o n a n d a d s o r p t i o n t o p a r t i c u l a t e s a n d o r g a n i c m a t r i c e s, r e s u l t i n t h e u b i q u i t o u s d i s t r i b u t i o n o f P O P s i n m a n y e n v i r o n m e n t a l c o m p a rt m e n t s ( O ' C o n n o r e t a l ; H u t z i n g e r ; E i t z e r ; M c L a c h l a n ; L o r b e r e t a l ). F o r e x a m p l e, v o l a t i l i s e d l o w e r c h l o r i n a t e d P C D D / F s c a n b e t r a n s p o r t e d l a r g e d i s t a n c e s f r o m t e m p e r a t e i n d u s t r i a l r e g i o n s, t o d e p o s i t i n c o l d c l i m a t e z o n e s ( S i m o n ic h a n d H i t e s ; B a r r i e e t a l ). W h i l e P C D D / F d i s t r i b u t i o n o c c u r s p r e d o m i n a n t l y v i a a t m o s p h e r i c t r a n s p o r t p a t h w a y s ( C z u c z w a a n d H i t e s ; K a l l e n b o r n e t a l ; L o h m a n a n d S e i g n e u r ), t h e i r s t r o n g a f f i n i t y f o r p a r t i c u l a t e s a l s o r e s u l t s i n s i g n i f i c a n t s e d i m e n t a n d s o i l a s s o c i a t e d t r a n s p o r t f r o m l o c a l p o i n t s o u r c e s a n d s o u r c e -i m p a c t e d t r i b u t a r i e s (Eitzer 1993; Pearson e t a l ). U l t i m a t e l y, t h e s e p a t h w a y s r e s u l t i n t h e i r a b s o r p t i o n t o a n d a c c u m u l a t i o n i n s o i l s a n d a q u a t i c s e d i m e n t s, w h e r e t h e y c a n p e r s i s t a n d a c c u m u l a t e t o e l e v a t e d c o n c e n t r a t i o n s ( C z u c z w a a n d H i t e s ; A l c o c k a n d J o n e s ). From these c o n t a m i n a t e d a b i o t i c c o m p a r t m e n t s, P C D D / F s c a n r e d i s t r i bu t e t o b i o a c c u m u l a t e i n b i o t a a n d c y c l e t h r o u g h t h e f o o d c h a i n ( C o n n e l l ; B r o m a n e t a l ; J a r m a n e t a l ; B e r g l u n d e t a l ). A q u a t i c e c o s y s t e m s a c t a s a n e n v i r o n m e n t a l s i n k f o r m a n y P O P s ( C o n n e l l ; A l c o c k a n d J o n e s ; B r i g h t e t a l ). M o r e o v e r, o n g o i n g e n v i r o n m e n t a l r e d i s t r i b u t i o n l e a d s t o a p r o g r e s s i v e t r a n s f e r o f t e r r e s t r i a l P O P l o a d s t o t h e s e a ( B o r r e l e t a l ). A s a c o n s e q u e n c e, p o l l u t a n t l o a d s i n t h e m a r i n e e n v i r o n m e n t w i l l c o n t i n u e t o i n c r e a s e, e v e n i f n o n e w i n p u t s o c c u r ( T a n a b e ; R o s s e t a l ). A c c u m u l a t i o n o f P C D D / F s i n m a r i n e s e d im e n t s r e m o v e a n d p r e s e r v e a f r a c t i o n o f e n v i r o n m e n t a l P C D D / F l o a d s ( C z u c z w a a n d H i t e s ; K j e l l e r a n d R a p p e ; B e r g l u n d e t a l. 2 1
22 C H A P T E R 1 IN T R O D U C T I O N ). H o w e v e r, s e d i m e n t s c a n a l s o r e d i s t r i b u t e t h e s e c o m p o u n d s w i t h i n t h e e c o s y s t e m. A c c u m u l a t i o n o f P O P s b y b i o t a f r o m t h e s u b s t r a t e a n d w a t e r c o l u m n r e s u l t s i n e n r i c h m e n t o f l e s s h y d r o p h o b i c c o n g e n e r s w i t h i n t h e f o o d c h a i n w h e r e t h e y c a n c y c l e a n d l e a d t o b i o m a g n i f i c a t i o n o f t h e m o r e t o x i c o l o g i c a l l y r e l e v a n t c o m p o u n d s i n h i g h er t r o p h i c o r g a n i s m s ( C o n n e l l ; B o r g a e t a l ). I n p a r t i c u l a r m a n y m a r i n e mammals are c o n s i d e r e d a m o n g t h e m o s t v u l n e r a b l e t o p o t e n t i a l l o n g-t e r m t o x i c e f f e c t s o f P O P s, d u e t o a c c u m u l a t e d h i g h l e v e l s i n t h e i r e n v i r o n m e n t, t h e i r h i g h f a t r e p o s i t o r i e s a n d h i g h p o s i t i o n i n t h e f o o d c h a i n, a s w e l l a s r e d u c e d m e t a b o l i c c a p a c i t i e s f o r c e r t a i n c o mp o u n d s ( T a n a b e e t a l ; B o r r e l l e t a l ; R o s s e t a l ; W a n i a a n d M a c k a y ). M a r i n e m a m m a l s h a v e b e e n u s e d s u c c e s s f u l l y a s b i o i n d i c a t o r s o f l o c a l a n d g l o b a l p o l l u t i o n o f p e r s i s t e n t o r g a n i c p o l l u t a n t s ( T a n a b e e t a l ; M ö s s n e r a n d B a l l s c h m i t e r ; N o r s t r o m e t a l ) a n d w i l d l i f e m o n i t o r i n g p r o v i d e s a n i m p o r t a n t c o m p o n e n t o f e n v i r o n m e n t a l r i s k m o n i t o r i n g ( C l a r k e t a l ). A n i s l a n d c o n t i n e n t, A u s t r a l i a i s s u r r o u n d e d b y t h e P a c i f i c O c e a n i n t h e e a s t, t h e I n d i a n O c e a n i n t h e w e s t, t h e S o u t h e r n O c e a n, a n d t h e s h a l l o w w a t e r s o f t h e T i m o r S e a, A r a f u r a S e a a n d T o r r e s t S t r a i t i n t h e n o r t h. T h e m a n y m a r i n e a n d e s t u a r i n e e n v i r o n m e n t s o f A u s t r a l i a s u s t a i n u n i q u e a n d d i v e r s e b i o t a, s u p p o r t e x t e n s i v e c o m m e r c i a l u s a g e s u c h a s f i s h e r i e s a n d t o u r i s m, a n d p r o v i d e s o c i a l a n d c u l t u r a l v a l u e s ( A S E C ). A u s t r a l i a s n a t u r a l a n d c u l t u r a l h e r i t a g e i s c l o s e l y t i e d t o t h e m a r i n e s y s t e m w h i c h i s c h a r a c t e r i s e d b y n u m e r o u s i n t e r n a t i o n a l l y r e c o g n i s e d m a r i t i m e a s s e t s ( A S E C ). W i t h i n t h e n o r t h e a s t e r n s t a t e o f Q u e e n s l a n d a l o n e, W o r l d H e r i t a g e l i s t e d a r e a s i n c l u d e F r a s e r I s l a n d i n t h e s o u t h e r n r e g i o n, a n d t h e m o r e t h a n k m l o n g G r e a t B a r r i e r R e e f. W i t h a n a v e r a g e o f 2 i n h a b i t a n t s p e r s q u a r e k i l o m e t r e, A u s t r a l i a h a s o n e o f t h e l o w e s t p o p u l a t i o n d e n s i t i e s i n t h e w o r l d ( A B S ). O f t h e m i l l i o n i n h a b i t a n t s, h o w e v e r, 8 4 % r e s i d e w i t h i n c o a s t a l u r b a n c e n t r e s, o c c u p y i n g < 1 % o f t h e c o n t i n e n t b y a r e a ( A B S ). 5 9 % o f A u s t r a l i a ' s l a n d m a s s i s c u r r e n t l y u s e d f o r a g r i c u l t u r a l a c t i v i t y ( A B S ). Q u e e n s l a n d h a s t h e l a r g e s t e s t i m a t e d l a n d a r e a f o r a g r i c u l t u r a l u s e, w i t h m i l l i o n h e c t a r e s, o r 3 2 % o f t h e n a t i o n a l t o t a l ( A B S ). The relatively f e r t i l e, n a r r o w c o a s t a l s t r i p o f Q u e e n s l a n d, s e p a r a t e d f r o m a n e x t e n s i v e a r i d i n l a n d a r e a b y m o u n t a i n r a n g e s, e x t e n d s m o r e t h a n k m f r o m S o u t h t o N o r t h. T h i s t r o p i c a l / s u b t r o p i c a l c o a s t a l z o n e i s c h a r a c t e r i s e d b y h i g h r a i n f a l l d u r i n g t h e s u m m e r w e t 2 2
23 C H A P T E R 1 IN T R O D U C T I O N s e a s o n ( D e c e m b e r-march), large river syst e m s, a n d e x t e n s i v e a g r i c u l t u r e s u c h a s s u g a r c a n e a n d g r a z i n g p a s t u r e s. C o m p a r e d t o t h e i n d u s t r i a l t e m p e r a t e c l i m a t e z o n e s, v e r y l i t t l e i n f o r m a t i o n e x i s t s o n P O P s i n m a r i n e s y s t e m s f r o m t h e s o u t h e r n h e m i s p h e r e a n d i n p a r t i c u l a r i n s u b t r o p i c a l o r t r o p i c a l c o u n t r i e s ( A g u i l a r e t a l ). A c c o r d i n g l y, m o d e l s o n t h e i r e n v i r o n m e n t a l f a t e a r e b a s e d o n t e m p e r a t e e c o s y s t e m s a n d s p e c i e s ( W a n i a a n d M a c k a y ). W i t h t h e i n c r e a s i n g u s e a n d / o r c o n t i n u e d r e l e a s e o f P O P s i n s u b t r o p i c a l a n d t r o p i c a l c o u n t r i e s, a n d t h e i n c r e a s i n g a w a r e n e s s o f e n v i r o n m e n t a l p o l l u t i o n i s s u e s, a n e e d t o r e f l e c t o n t h e i m p a c t o f e n v i r o n m e n t a l a n d c l i m a t i c v a r i a b i l i t y o n t h e f a t e o f P O P s w a s i d e n t i f i e d ( W a n i a a n d M a c k a y ). T h e r e l a t i v e l y f e w P C D D / F s t u d i e s r e p o r t e d f r o m c o u n t r i e s i n S o u t h A m e r i c a e. g. ( A s s u n c a o a n d P e s q u e r o ; G r o s s i e t a l ; B r a g a e t a l ; C a r v a l h a e s e t a l ) a n d A f r i c a e. g. ( L o h m a n n e t a l ) d e m o n s t r a t e t h a t r e l e v a n t P C D D / F s o u r c e s e x i s t, a t l e a s t o n a l o c a l o r r e g i o n a l s c a l e. S i m i l a r l y, e l e v a t e d P C D D / F c o n c e n t r a t i o n s h a v e b e e n r e p o r t e d f r o m s o i l s a m p l e s w i t h i n Q u e e n s l a n d s s u g a r c a n e p l a n t a t i o n s ( M ü l l e r e t a l ). A l t h o u g h o n l y a l i m i t e d n u m b e r o f s a m p l e s w e r e a n a l y s e d, t h e s u b s e q u e n t i n v e s t i g a t i o n i n t o m a r i n e s e d i m e n t a n d b i o t a f r o m Q u e e n s l a n d s u g g e s t e d t h a t a s i g n i f i c a n t s o u r c e m a y e x i s t i n t h e c o a s t a l z o n e ( H a y n e s e t a l ; M ü l l e r e t a l c ; M c L a c h l a n e t a l ). T h e p r e s e n t s t u d y w a s d e s i g n e d t o i n v e s t i g a t e t h e p o t e n t i a l P C D D / F c o n t a m i n a t i o n o f t h e Q u e e n s l a n d c o a s t a l z o n e. F o c u s w a s p l a c e d i n p a r t i c u l a r o n t h e m a r i n e e n v i r o n m e n t s i n c e t h i s s y s t e m i s a s i n k f o r l i p o p h i l i c c o m p o u n d s s u c h a s P C D D / F s. D u e t o t h e v e r y l i m i t e d i n f o r m a t i o n a v a i l a b l e o n P C D D / F s i n Q u e e n s l a n d, t h i s s t u d y a i m e d t o p r o v i d e i n f o r m a t i o n o n t h e s o u r c e s, d i s t r i b u t i o n a n d pa t h w a y s o f P C D D / F s i n t o a n d w i t h i n t h e m a r i n e e n v i r o n m e n t. S u c h k n o w l e d g e i s f u n d a m e n t a l t o a s s e s s i n g t h e r i s k s a s s o c i a t e d w i t h t h e p r e s e n c e o f P C D D / F s i n t h e e n v i r o n m e n t. B a s e d o n t h e s e n e e d s, t h e o b j e c t i v e s o f t h i s s t u d y w e r e d e f i n e d a s : o Assess the sp a t i a l e x t e n t o f P C D D / F c o n t a m i n a t i o n a l o n g t h e Q u e e n s l a n d c o a s t l i n e, o P r o v i d e i n f o r m a t i o n o n t h e p o s s i b l e s o u r c e s a n d f o r m a t i o n p r o c e s s e s i n v o l v e d, o I d e n t i f y t h e p a t h w a y s o f P C D D / F s t o a n d w i t h i n t h e m a r i n e e n v i r o n m e n t, o I n v e s t i g a t e t h e p r o c e s s e s t h a t i n f l ue n c e P C D D / F p a t h w a y s a n d p r o c e s s e s, o D e t e r m i n e t h e p o t e n t i a l f o r P C D D / F b i o a c c u m u l a t i o n i n b i o t a, 2 3
24 C H A P T E R 1 IN T R O D U C T I O N o P r o v i d e i n f o r m a t i o n n e c e s s a r y f o r t h e a s s e s s m e n t o f r i s k s t o t h e n e a r s h o r e m a r i n e e n v i r o n m e n t a n d w i l d l i f e. C h a p t e r s 2-6 i n t h i s t h e s i s r e f l e c t m y a p p r o a c h t o i d e n t i f y i n g t h e i n t e r a c t i o n s o f P C D D / F s f r o m f o r m a t i o n a l o n g t h e i r p a t h w a y s i n t h e d i f f e r e n t e n v i r o n m e n t a l c o m p a r t m e n t s. Chapter 2 i n v e s t i g a t e s t h e p r e s e n c e o f P C D D / F s o n l a n d a n d i n t h e m a r i n e s y s t e m a l o n g t h e Q u e e n s l a n d c o a s t l i n e. T h e s p a t i a l d i s t r i b u t i o n o f P C D D / F s i n Q u e e n s l a n d s m a r i n e e n v i r o n m e n t w a s a s s e s s e d, t o p r o v i d e i n f o r m a t i o n o n t h e s i g n i f i c a n c e a n d e x t e n t o f c o n t a m i n a t i o n. I n Chapter 3, t h e h i s t o r i c a l r e c o r d s o f P C D D / F p r o f i l e s, p r e s e r v e d i n t h e s e d i m e n t e n v i r o n m e n t, w e r e i n v e s t i g a t e d u si n g d a t e d s e d i m e n t c o r e s. T h e v e r t i c a l d i s t r i b u t i o n o f P C D D / F c o n c e n t r a t i o n s a n d c o n g e n e r p r o f i l e s w a s d e t e r m i n e d, p r o v i d i n g i n f o r m a t i o n o n t h e t e m p o r a l e x t e n t a n d p o t e n t i a l o r i g i n o f P C D D / F s i n Q u e e n s l a n d. Chapter 4 f o c u s e d o n t h e p r o c e s s e s t h a t i n f l u e n c e P C D D / F s i n t h e a b i o t i c m a r i n e e n v i r o n m e n t. A s a r e s u l t o f t h e h i s t o r i c a l P C D D / F d i s t r i b u t i o n, i t w a s h y p o t h e s i s e d t h a t t r a n s f o r m a t i o n p r o c e s s e s m a y o c c u r i n t h e m a r i n e e n v i r o n m e n t. T h e p o t e n t i a l f o r s u c h t r a n s f o r m a t i o n s a n d t h e i r p a t h w a y s w a s t h e r e f o r e i n v e s t i g a t e d, u s i n g d a t e d s e d i m e n t c o r e s. I n Chapter 5, a n e v a l u a t i o n o f t h e e x i s t i n g i n f o r m a t i o n o n t h e P C D D / F p a t h w a y s, a c c u m u l a t i o n a n d p r o c e s s e s i n t h e m a r i n e e n v i r o n m e n t w a s u s e d t o e s t a b l i s h a n a l t e r n a t i v e h y p o t h e s i s o n t h e f o r m a t i o n a n d p o s s i b l e s o u r c e s o f P C D D / F s i n t h e Q u e e n s l a n d e n v i r o n m e n t. Chapter 6 d e t e r m i n e d t h e t r a n s p o r t i n t o a n d r e d i s t r i b u t i o n p a t h w a y s w i t h i n t h e n e a r s h o r e m a r i n e s y s t e m. T h e p o t e n t i a l f o r a n d e x t e n t o f P C D D / F b i o a c c u m u l a t i o n i n Q u e e n s l a n d s i n s h o r e m a r i n e b i o t a w a s i n v e s t i g a t e d u s i n g t h e h e r b i v o r o u s m a r i n e m a m m a l d u g o n g ( D u g o n g d u g o n ). F a c t o r s t h a t i n f l u e n c e t h e P C D D / F b o d y b u r d e n s i n d u g o n g s, s u c h a s a b s o r p t i o n, m e t a b o l i s m a n d t r a n s f e r, w e r e i n v e s t i g a t e d. T h e s e d a t a p r o v i d e d p e r t i n e n t i n f o r m a t i o n f o r t h e a s s e s s m e n t o f t h e p o t e n t i a l r i s k s a s s o c i a t e d w i t h t h e p r e s e n c e o f e l e v a t e d P C D D / F c o n c e n t r a t i o n s i n t h e n e a r s h o r e m a r i n e e c o s y s t e m. T h e f i n a l Chapter 7 p r o v i d e s a n o v e r v i e w o n t h e k e y f i n d i n g s o f t h i s t h e s i s. B a s e d o n t h e s e f i n d i n g s, a g e n e r a l i s e d c o n c e p t u a l m o d e l o n t h e s o u r c e s, p a t h w a y s, p r o c e s s e s a n d f a t e o f d i o x i n s i n t h e Q u e e n s l a n d m a r i n e e n v i r o n m e n t i s p r e s e n t e d. T h i s m o d e l s e r v e s a s t h e b a s i s f o r a s u b s e q u e n t d i s c u s s i o n o n p o t e n t i a l i m p l i c a t i o n s f o r t h e e n v i r o n m e n t, w i l d l i f e a n d h u m a n s a n d p e r t i n e n t f u t u r e re s e a r c h i n Q u e e n s l a n d, A u s t r a l i a a n d e l s e w h e r e. 2 4
25 C H A P T E R 1 IN T R O D U C T I O N T h e r e s u l t s a n d d i s c u s s i o n s i n t h i s t h e s i s h a v e b e e n p u b l i s h e d, s u b m i t t e d o r h a v e b e e n a c c e p t e d f o r p u b l i c a t i o n b y r e v i e w e d j o u r n a l s a s o u t l i n e d o n t h e t i t l e p a g e o f e a c h c h a p t e r, a n d a s s u m m a r i s e d b e l o w : G a u s, C., P ä p k e, O., D e n n i s o n, N., H a y n e s, D., S h a w, G. R., C o n n e l l, D. W. a n d M ü l l e r, J. F E v i d e n c e f o r t h e p r e s e n c e o f a w i d e s p r e a d P C D D s o u r c e i n c o a s t a l s e d i m e n t s a n d s o i l s f r o m Q u e e n s l a n d, A u s t r a l i a. C h e m o s p h e r e 43(4-7 ) : G a u s, C., M ü l l e r, J. F. a n d P ä p k e, O. R e v i e w o n h i s t o r i c a l, t o p s o i l a n d s u r f a c e s e d i m e n t s a m p l e s i n d i c a t i n g t h e p r e s e n c e o f n o n-a n t h r o p o g e n i c P C D D / F s o u r c e s. a c c e p t e d i n C h e m o s p h e r e G a u s, C., P ä p k e, O., B r u n s k i l l, G. J. a n d M ü l l e r, J. F H i s t o r i c a l P C D D / F r e c o r d s i n d a t e d m a r i n e s e d i m e n t c o r e s f r o m Q u e e n s l a n d, A u s t r a l i a. O r g a n o h a l o g e n C o m p o u n d s 4 6 : G a u s, C., B r u n s k i l l, G., J, W e b e r, R., P ä p k e, O. a n d M ü l l e r, J. F H i s t o r i c a l P C D D i n p u t s a n d t h e i r s o u r c e i m p l i c a t i o n s f r o m d a t e d s e d i m e n t c o r e s i n Q u e e n s l a n d ( A u s t r a l i a ). E n v i r o n m e n t a l S c i e n c e a n d T e c h n o l o g y 3 5 : G a u s, C., W e b e r, R., C o n n e l l, D. W., B r u n s k i l l, G., J, P r a n g e, J. A., P ä p k e, O. a n d M ü l l e r, J. F D e p o s i t i o n a l p r o c e s s e s a n d t h e i r s o u r c e i m p l i c a t i o n s f rom t e m p o r a l P C D D d i s t r i b u t i o n s i n Q u e e n s l a n d ( A u s t r a l i a ). O r g a n o h a l o g e n C o m p o u n d s 5 0 : G a u s, C., B r u n s k i l l, G. J., C o n n e l l, D. W., P r a n g e, J., M ü l l e r, J., P ä p k e, O. a n d W e b e r, R T r a n s f o r m a t i o n p r o c e s s e s, p a t h w a y s a n d p o s s i b l e s o u r c e s o f d i s t i n c t i v e p o l y c h l o r i n a t e d d i b e n z o -p-d i o x i n s i g n a t u r e s i n s i n k e n v i r o n m e n t s. E n v i r o n m e n t a l S c i e n c e a n d T e c h n o l o g y - i n p r i n t, p u b l i s h e d o n E S & T w e b s i t e J u l y G a u s, C., P r a n g e, J. A., C o n n e l l, D. W., B r u n s k i l l, G., J, P ä p k e, O., M ü l l e r, J. F. a n d W e b er, R T r a n s f o r m a t i o n o f d i o x i n s i n e n v i r o n m e n t a l s i n k s - 2 5
26 C H A P T E R 1 IN T R O D U C T I O N f o r m a t i o n o f t h e d i s t i n c t i v e " n a t u r a l P C D D s i g n a t u r e ". O r g a n o h a l o g e n C o m p o u n d s s u b m i t t e d. G a u s, C., P r a n g e, J., P ä p k e, O., M ü l l e r, J. F. a n d W e b e r, R A n a l t e r n a t i v e h y p o t h e s i s t o n a t u r a l P C D D f o r m a t i o n. O r g a n o h a l o g e n C o m p o u n d s a c c e p t e d J u n e G a u s, C., P ä p k e, O., B l a n c h a r d, W., H a y n e s, D., C o n n e l l, D. W. a n d M ü l l e r, J. F B i o a c c u m u l a t i o n a n d p a t h w a y s o f P C D D s i n t h e l o w e r t r o p h i c m a r i n e system. O r g a n o h a l o g e n C o m p o u n d s 5 2 : G a u s, C., O ' D o n o h u e, M., P ä p k e, O. a n d M ü l l e r, J. P a t h w a y s o f d i o x i n s a n d c o n t a m i n a t i o n o f t h e m a r i n e h e r b i v o r o u s m a m m a l D u g o n g d u g o n i n Q u e e n s l a n d, A u s t r a l i a. s u b m i t t e d t o E n v i r o n m e n t a l T o x i c o l o g y a n d C h e m i s t r y. 2 6
27 CHAPTER 2 SPATIAL DISTRIBUTION OF PCDD/Fs IN QUEENSLAND Evidence for the presence of a widespread source Published in: Chemosphere 2002 (Volume 43, pages )
28 This chapter was previously published as: Caroline Gaus (et al.). Evidence for the presence of a widespread PCDD source in coastal sediments and soils from Queensland, Australia, Chemosphere, vol. 43, issues 4-7 (May 2001), pp Reproduced with permission from Elsevier Science Ltd. Copyright 2001 Elsevier Science Ltd.
29 C H A P T E R 2 SP A T I A L D I S T R I B U T I O N ABSTRACT R e c e n t s t u d i e s h a v e d e m o n s t r a t e d t h e o c c u r r e n c e o f e l e v a t e d l e v e l s o f h i g h e r c h l o r i n a t e d p o l y c h l o r i n a t e d d i b e n z o -p-d i o x i n s ( P C D D s ) i n t h e c o a s t a l e n v i r o n m e n t o f Q u e e n s l a n d, A u s t r a l i a. T h i s s t u d y p r e s e n t s n e w d a t a f o r o c t a c h l o r o d i b e n z o d i o x i n ( O C D D ) c o n t a m i n a t i o n a n d f u l l P C D D / F p r o f i l e a n a l y s i s i n t h e e n v i r o n m e n t o f Q u e e n s l a n d. M a r i n e s e d i m e n t s, i r r i g a t i o n d r a i n s e d i m e n t s a n d t o p s o i l w e r e c o l l e c t e d f r o m s i t e s t h a t w e r e e x p e c t e d t o b e i n f l u e n c e d b y s p e c i f i c l a n d -u s e t y p e s. H i g h O C D D c o n c e n t r a t i o n s w e r e a s s o c i a t e d m a i n l y w i t h s e d i m e n t s c o l l e c t e d n e a r t h e m o u t h o f r i v e r s, w h i c h d r a i n l a r g e c a t c h m e n t s i n t h e t r o p i c a l a n d s u b t r o p i c a l r e g i o n. F u r t h e r, a n a l y s i s o f s e d i m e n t s f r o m a g r i c u l t u r a l i r r i g a t i o n d r a i n s c o u l d b e c l e a r l y d i f f e r e n t i a t e d o n t h e b a s i s o f O C D D c o n t a m i n a t i o n, w i t h h i g h c o n c e n t r a t i o n s i n s a m p l e s f r o m s u g a r c a n e d r a i n s c o l l e c t e d f r o m c o a s t a l r e g i o n s, a n d l o w c o n c e n t r a t i o n s i n d r a i n s e d i m e n t s f r o m d r i e r i n l a n d c o t t o n g r o w i n g a r e a s. P C D D / F c o n g e n e r s p e c i f i c a n a l y s i s d e m o n s t r a t e d a l m o s t i d e n t i c a l c o n g e n e r p r o f i l e s i n a l l s a m p l e s c o l l e c t e d a l o n g t h e c o a s t l i n e. T h i s i n d i c a t e s t h e s o u r c e t o b e w i d e s p r e a d a l o n g t h e c o a s t a l z o ne. P r o f i l e s w e r e d o m i n a t e d b y h i g h e r c h l o r i n a t e d P C D D s, i n p a r t i c u l a r O C D D w h e r e a s 2, 3, 7, 8 - s u b s t i t u t e d P C D F s w e r e b e l o w t h e l i m i t o f q u a n t i f i c a t i o n i n t h e m a j o r i t y o f s a m p l e s. T h e f u l l P C D D / F p r o f i l e s o f a l l s a m p l e s r e s e m b l e t h o s e r e p o r t e d f o r l a k e s e d i me n t s f r o m M i s s i s s i p p i a n d k a o l i n i t e s a m p l e s f r o m G e r m a n y. S t r o n g s i m i l a r i t i e s t o t h e s e s a m p l e s w i t h r e s p e c t t o c o n g e n e r p r o f i l e s a n d i s o m e r p a t t e r n s m a y i n d i c a t e t h e p r e s e n c e o f a s i m i l a r s o u r c e a n d / o r f o r m a t i o n p r o c e s s t h a t i s y e t u n i d e n t i f i e d. 2 8
30 C H A P T E R 2 SP A T I A L D I S T R I B U T I O N 2.1 INTRODUCTION Q u e e n s l a n d, t h e n o r t h e a s t e r n s t a t e o f A u s t r a l i a h a s a c o a s t l i n e t h a t s t r e t c h e s m o r e t h a n k m f r o m s o u t h t o n o r t h a n d i s f a m o u s f o r i t s p r i s t i n e e n v i r o n m e n t s, w h i c h i n c l u d e t h e G r e a t B a r r i e r R e e f. M o u n t a i n r a n g e s s e p a r a t e a n e x t e n s i v e a r i d i n l a n d a r e a f r o m a n a r r o w s u b t r o p i c a l / t r o p i c a l c o a s t l i n e. H i g h r a i n f a l l d u r i n g t h e w e t s e a s o n, e x t e n s i v e r i v e r s y s t e m s a n d l a r g e r u r a l r e g i o n s c h a r a c t e r i s e t h e c o a s t a l p l a i n s. C a t t l e g r a z i n g a n d i n t e n s i v e a g r i c u l t u r e d o m i n a t e t h e r u r a l r e g i o n s, w h e r e c o t t o n a n d sugar cane are among t h e m a i n c r o p s i n t h e h i n t e r l a n d a n d t r o p i c a l c o a s t a l p l a i n r e s p e c t i v e l y. W i t h t w o -t h i r d s o f t h e t h r e e m i l l i o n i n h a b i t a n t s o f Q u e e n s l a n d l i v i n g i n t h e B r i s b a n e m e t r o p o l i t a n a r e a ( s o u t h e a s t c o r n e r o f t h e s t a t e ) i n d u s t r i a l a c t i v i t i e s a re r e l a t i v e l y l o w i n n o r t h e r n Q u e e n s l a n d. H e n c e i t h a s b e e n a s s u m e d t h a t f e w r e l e v a n t P C D D / F s o u r c e s e x i s t a n d a s a c o n s e q u e n c e, P C D D / F c o n c e n t r a t i o n s a r e l o w i n t h e e n v i r o n m e n t o f N o r t h Q u e e n s l a n d. H o w e v e r, e l e v a t e d P C D D l e v e l s, i n p a r t i c u l a r O C D D h a v e b e e n f o u n d i n b l u b b e r f r o m t h r e e d u g o n g s, (D u g o n g d u g o n) ( H a y n e s e t a l ) t h e i r s e a g r a s s f o o d s o u r c e ( M c L a c h l a n e t a l ), a s w e l l a s a s m a l l n u m b e r o f s e d i m e n t s a n d a g r i c u l t u r a l s o i l s a m p l e s c o l l e c t e d f r o m n o r t h e r n Q u e e n s l a n d ( M ü l l e r e t a l c ). A l t h o u g h i t h a s b e e n s u g g e s t e d t h a t e l e v a t e d P C D D / F s a r e l i n k e d w i t h a r e a s u s e d f o r s u g a r c a n e c u l t i v a t i o n, t h e s o u r c e ( s ) a n d p r o c e s s ( e s ) w h i c h h a v e r e s u l t e d i n t h e c o n t a m i n a t i o n r e m a i n u n k n o w n. P C D D / F s c a n b e r e l e a s e d i n t o t h e e n v i r o n m e n t f r o m a n u m b e r o f s o u r c e s i n c l u d ing c o m b u s t i o n o f c h l o r i n a t e d p r o d u c t s, a n d a s a c o n t a m i n a t e d b y-p r o d u c t i n v a r i o u s o r g a n i c p r o d u c t s a n d c h e m i c a l s. C o n t a m i n a t e d i n d u s t r i a l a n d d o m e s t i c w a s t e w a t e r a n d r u n-o f f, a s w e l l a s a t m o s p h e r i c d e p o s i t i o n o f P C D D / F s e m i t t e d f r o m c o m b u s t i o n s o u r c e s, c a n r e s u l t i n c o n t a m i n a t i o n o f a q u a t i c s y s t e m s w h e r e s e d i m e n t s p r o v i d e s i n k s f o r p e r s i s t e n t l i p o p h i l i c c h e m i c a l s ( F i e d l e r ). A n u m b e r o f P C D D / F s o u r c e s a r e c h a r a c t e r i s e d b y c o n g e n e r p r o f i l e s d o m i n a t e d b y O C D D. T h e s e i n c l u d e f o r e x a m p l e P C D D / F c o n t a m i n a t i o n i n p e n t a c h l o r o p h e n o l ( H a g e n m a i e r a n d B r u n n e r ; A l c o c k a n d J o n e s ), i n s e w a g e s l u d g e ( R a p p e e t a l ; K l i m m e t a l ) a n d d e p o s i t i o n s o f a t m o s p h e r i c P C D D / F s w h i c h w e r e s u b j e c t t o l o n g-r a n g e t r a n s p o rt ( T y s k l i n d e t a l ). T h e o c c u r r e n c e o f h i g h e r c h l o r i n a t e d P C D D s i n s e d i m e n t s h a v e 2 9
31 C H A P T E R 2 SP A T I A L D I S T R I B U T I O N a l so b e e n a t t r i b u t e d t o n a t u r a l f o r m a t i o n p r o c e s s e s ( H a s h i m o t o e t a l ; R a p p e e t a l a ; b ) a n d m a y p r o v i d e b a s e l i n e l e v e l s o f t h e s e c o m p o u n d s i n s p e c i f i c e n v i r o n m e n t s. T h e a i m o f t h i s s t u d y w a s t o d e t e r m i n e P C D D / F, a n d i n p a r t i c u l a r O C D D c o n t a m i n a t i o n i n s e d i m e n t s a n d s o i l s f r o m Q u e e n s l a n d a n d t o i d e n t i f y a r e a s i n w h i c h c o n c e n t r a t i o n s a r e e l e v a t e d. S a m p l i n g w a s f o c u s e d o n t e r r e s t r i a l a n d e s t u a r i n e a r e a s t h a t a r e s u b j e c t t o s p e c i f i c a n t h r o p o g e n i c a c t i v i t i e s o r l a n d u s e ( e. g. a g r i c u l t u r a l o r u r b a n ), t o w h i c h h i g h e r c o n t a m i n a t i o n m a y b e a t t r i b u t e d. T h i s s a m p l i n g a p p r o a c h t o g e t h e r w i t h a n a l y s i s o f c o n g e n e r p r o f i l e s a n d i s o m e r p a t t e r n s a r e p a r t o f t h e s t r a t e g y t o i d e n t i f y k e y P C D D / F s o u r c e s i n Q u e e n s l a n d. 2.2 MATERIALS AND METHODS SAMPLING F o r t h e p u r p o s e o f t h i s s t u d y, 2 4 m a r i n e s e d i m e n t s, 1 1 i r r i g a t i o n d r a i n s e d i m e n t s a n d 3 s o i l s a m p l e s w e r e c o l l e c t e d a n d a n a l y s e d ( F i g u r e 2. 1 ). M a r i n e s e d i m e n t s ( M 1-M 2 4, n u m b e r e d f r o m n o r t h t o s o u t h ) w e r e c o l l e c t e d i n s u b t i d a l a r e a s u s i n g a m o d i f i e d V a n V e e n s a m p l e r. M 1 r e p r e s e n t s a c o n t r o l s i t e d i s t a n t f r o m m a j o r a g r i c u l t u r a l o r u r b a n c e n t r e s. M 2-M 5, M 1 2, M 1 3, M 1 6, M 1 9, M 2 2 a n d M 2 3 w e r e m a r i n e s e d i m e n t s c o l l e c t e d n e a r t h e m o u t h o f r i v e r s. O f t h e s e, M 2 -M 5, M 1 2, M 1 3 a n d M 1 9 w e r e c o l l e c t e d n e a r t h e m o u t h o f r i v e r s w i t h s u g a r c a n e c a t c h m e n t s. M 1 5 -M 1 7 a r e l o c a t e d n e a r a n u r b a n c e n t r e, T o w n s v i l l e ( p o p u l a t i o n 1 3 0, ) a n d M 2 2 a t t h e m o u t h o f a r i v e r w h i c h p a s s e s t h r o u g h a c o t t o n g r o w i n g a r e a a s w e l l a s a s m a l l e r u r b a n c e n t r e ( p o p u l a t i o n 7 0, ). M 6 -M 1 1 a n d M 1 4 w e r e s a m p l e s c o l l e c t e d f u r t h e r a w a y f r o m r i v e r m o u t h s i n a r e a s d o m i n a t e d b y s u g a r c a n e c u l t i v a t i o n. M 1 8 w a s l o c a t e d o f f s h o r e a s u g a r c a n e a r e a, M 2 0 a n d M 2 1 w e r e s e d i m e n t s c o l l e c t e d o f f s h o r e a n a r e a u s e d m a i n l y f o r cattle grazing. M23 -M 2 4 w e r e l o c a t e d i n t h e v i c i n i t y o f B r i s b a n e a n d s u r r o u n d i n g s o u t h e a s t Q u e e n s l a n d s m e t r o p o l i t a n a r e a ( p o p u l a t i o n a p p r o x i m a t e l y 2 m i l l i o n ) a n d, t o g e t h e r w i t h M 2 0, h a v e b e e n r e p o r t e d p r e v i o u s l y ( M ü l l e r e t a l c ). A t e a c h m a r i n e s i t e t w o t o f o u r s u b s a m p l e s w e r e c o l l e c t e d w h i l e t h e r e s e a r c h v e s s e l w a s d r i f t i n g o v e r a c h o s e n s i t e. 3 0
32 C H A P T E R 2 SP A T I A L D I S T R I B U T I O N I r r i g a t i o n d r a i n s e d i m e n t s ( I 1 -I 1 1 ) w e r e c o l l e c t e d f r o m r e g i o n s d o m i n a t e d b y e i t h e r sugar cane (I1 -I 5 ) o r c o t t o n c u l t i v a t i o n ( I 6 -I 1 1 ). S i t e s I 2 a n d I 6 w e r e h o w e v e r i n t h e d i r e c t vi c i n i t y o f a m a n g o f a r m a n d a c o n s e r v a t i o n a r e a r e s p e c t i v e l y. E i g h t s u b s a m p l e s w e r e t a k e n a t e a c h i r r i g a t i o n d r a i n s i t e o v e r a d i s t a n c e o f 8 0 m ( o n e s u b s a m p l e a p p r o x i m a t e l y e v e r y 1 0 m ). S o i l s a m p l e s ( t o p 5 c m ) w e r e c o l l e c t e d f r o m a s u g a r c a n e field (T1), a n a d j a c e n t g r a z i n g p a d d o c k ( T 2 ) a n d a f o r e s t s i t e i n a m o u n t a i n o u s N a t i o n a l P a r k w h i c h i s l o c a t e d u p s t r e a m o f a m a j o r s u g a r c a n e g r o w i n g a r e a. F i v e s u b s a m p l e s w e r e c o l l e c t e d a t e a c h o f t h e s e s i t e s ANALYSIS S u b s a m p l e s f r o m a g i v e n s i t e w e r e c o m b i n e d i n t h e f i e l d a n d h o m o g e n i s e d t o f o r m o n e c o m p o s i t e s a m p l e. S a m p l e s w e r e f r e e z e -d r i e d, g r o u n d a n d s i e v e d, a n d o n l y t h e f r a c t i o n c o n s i s t i n g o f p a r t i c l e s s m a l l e r t h a n 2. 3 m m w a s a n a l y s e d. T h e m a j o r i t y o f s e d i m e n t s w e r e a n a l y s e d a t Q u e e n s l a n d H e a l t h S c i e n t i f i c S e r v i c e s ( Q H S S ) l a b o r a t o r i e s u s i n g a s c r e e n i n g m e t h o d e s t a b l i s h e d t o a n a l y s e s a m p l e s f o r O C D D c o n c e n t r a t i o n s ( d e t a i l e d d e s c r i p t i o n i n ( M ü l l e r e t a l a )). In brief, 10 g of dry sa m p l e w e r e h o m o g e n i s e d w i t h 1 5 g o f N a 2 SO 4, t r a n s f e r r e d i n t o s o x h l e t s a n d e x t r a c t e d f o r 2 0 h o u r s u s i n g a c e t o n e / h e x a n e ( 1 : 1 ). A b l a n k c o n s i s t i n g o f N a 2 SO 4 a n d a b l a n k s p i k e d w i t h O C D D w e r e i n c l u d e d w i t h e a c h b a t c h o f 6 t o 1 2 s a m p l e s. D u r i n g t h i s s t u d y, t h e o r i g i n a l m e t h o d w a s m o d i f i e d t o i n c l u d e 1, 2, 3, 4, 7, 8, 9 -H p C D F a s a n i n t e r n a l s t a n d a r d o f k n o w n q u a n t i t y, w h i c h w a s s p i k e d t o t h e s a m p l e b e f o r e e x t r a c t i o n. T h e e x t r a c t w a s c o n c e n t r a t e d a n d s u b j e c t t o c l e a n -u p o n a c i d / b a s e a c t i v a t e d s i l i c a g e l. S e p a r a t i o n o f t h e P C D D / F s f r o m P C B s a n d o t h e r c o -c o n t a m i n a n t s w a s p e r f o r m e d o n a n a l u m i n a c o l u m n ( A l o x B-s u p e r, I C N ). A f t e r c l e a n -u p p r o c e d u r e s, s a m p l e s w e r e c o n c e n t r a t e d a l m o s t t o d r y n e s s a n d f i l l e d w i t h 2 0 µl o f t o l u e n e c o n t a i n i n g a k n o w n a m o u n t o f d i b u t y l c h l o r i n d at e, t h e l a t t e r b e i n g u s e d t o a s s e s s t h e p e r f o r m a n c e o f t h e i n s t r u m e n t a n d / o r v o l u m e d i f f e r e n c e s i n t h e v i a l. S a m p l e s w e r e a n a l y s e d o n a G C ( D B 5 ; 3 0 m, m m i. d., µm f i l m t h i c k n e s s ) e q u i p p e d w i t h a n e l e c t r o n c a p t u r e d e t e c t o r. Q u a n t i f i c a t i o n w a s p er f o r m e d u s i n g e x t e r n a l c a l i b r a t i o n w i t h k n o w n c o n c e n t r a t i o n s o f a r a n g e o f O C D D s t a n d a r d s. W h e n t h e i n t e r n a l s t a n d a r d m e t h o d w a s i n t r o d u c e d, a c a l i b r a t i o n o f t h e r e s p o n s e o f t h e i n t e r n a l s t a n d a r d t o O C D D p l u s a c a l i b r a t i o n o f t h e r e l a t i v e r e s p o n s e o f t h e re c o v e r y s t a n d a r d t o t h e i n t e r n a l s t a n d a r d c o n c e n t r a t i o n w a s p e r f o r m e d. C o n f i r m a t i o n o f O C D D w a s c a r r i e d o u t i n s a m p l e s w i t h r e l a t i v e l y h i g h O C D D l e v e l s u s i n g G C -M S, w h e r e t h e M S w a s o p e r a t e d i n m u l t i i o n s c a n. 3 1
33 C H A P T E R 2 SP A T I A L D I S T R I B U T I O N A f u l l a n a l y s i s o f a l l 2, 3, 7, 8 -s u b s t i t u t e d P C D D / F s w a s c a r r i e d o u t o n a s e l e c t i o n o f s a m p l e s a t E r g o F o r s c h u n g s g e s e l l s c h a f t m b H ( E R G O ) u s i n g a s t a n d a r d i s e d p r o c e d u r e ( K l ä r s c h l a m m v e r o r d n u n g ). A t E R G O, 8 g o f s e d i m e n t w a s s p i k e d w i t h 13 C - l a b e l l e d P C D D / F s t a n d a r d. S e d i m e n t s w e r e t h e n s o x h l e t e x t r a c t e d f o r 2 0 h o u r s u s i n g t o l u e n e, a n d a b l a n k w a s i n c l u d e d w i t h e a c h b a t c h o f 6 t o 1 2 s a m p l e s. T h e e x t r a c t s w e r e c o n c e n t r a t e d a n d c o -c o n t a m i n a n t s r e m o v e d o n a n a l u m i n u m o x i d e c o l u m n ( A l u m i n a B -S u p e r, I C N ). S a m p l e s w e r e f u r t h e r s u b j e c t t o p u r i f i c a t i o n o n a c t i v a t e d c a r b o n. A f t e r c o n c e n t r a t i o n o f t h e e l u e n t t o n e a r d r y n e s s, s a m p l es w e r e t r a n s f e r r e d t o 1 v i a l s a n d 3 C -l a b e l l e d 1, 2, 3, 4 -T C D D r e c o v e r y s t a n d a r d w a s a d d e d. A n a l y s i s o f t e t r a - t o o c t a-c D D / F s w a s p e r f o r m e d o n a G C ( D B-5 f u s e d s i l i c a c o l u m n, 6 0 m, m m i. d., 0. 1 µm f i l m t h i c k n e s s ) i n t e r f a c e d t o a V G A u t o s p e c m a s s s p e c t r o m e t e r o p e r a t i n g o n a r e s o l u t i o n o f a p p r o x i m a t e l y 1 0, I d e n t i f i c a t i o n o f 2, 3, 7, 8 -s u b s t i t u t e d P C D D / F s w a s p e r f o r m e d u s i n g r e t e n t i o n t i m e s o f t h e l a b e l l e d s t a n d a r d s a n d i s o t o p e r a t i o s a t M + a n d M N o n-2, 3, 7, 8 -s u b s t i t u t e d P C D D / F s w e r e d e t e r m i n e d u s i n g t h e r e l a t i v e r e t e n t i o n t i m e s o f t h e s e c o m p o u n d s o n a D B 5 c o l u m n a s p r o v i d e d b y R a p p e ( u n p u b l i s h e d d a t a ). F o r q u a l i t y c o n t r o l, t h e r e t e n t i o n t i m e s o f t h e a n a l y t e i n a s a m p l e h a d t o b e w i t h i n 2 s o f t h e r e t e n t i o n t i m e s o f t h e i n t e r n a l s t a n d a r d s. T h e l i m i t o f q u a n t i f i c a t i o n f o r P C D D / F s o r O C D D i n a g i v e n s a m p l e w a s d e f i n e d b y a s i g n a l t o n o i s e r a t i o g r e a t e r t h a n 3 t i m e s t h e a v e r a g e b a s e l i n e v a r i a t i o n a n d a s u b s t a n c e q u a n t i t y i n t h e s a m p l e g r e a t e r t h a n 3 t i m e s t h e q u a n t i t y i n t h e r e s p e c t i v e b l a n k. T h e r e c o v e ri e s o f i n d i v i d u a l P C D D / F c o n g e n e r s r a n g e d f r o m 4 5 % t o %. T h e a n a l y t i c a l v a r i a b i l i t y w a s t e s t e d b y r e p l i c a t e a n a l y s i s o f s a m p l e s I 2, I 5 a n d I 8, r e s p e c t i v e l y. T h e v a r i a b i l i t y o f t h e s a m p l i n g p r o c e d u r e a t a given sampling site was tested by analysing i n d i v i d u a l s u b s a m p l e s c o l l e c t e d a t s i t e s M 9 a n d M 2 1. S p a t i a l p l u s t e m p o r a l v a r i a b i l i t y b e t w e e n s a m p l e s i t e s c o l l e c t e d f r o m a g i v e n l o c a t i o n ( i. e. a b a y o r r i v e r m o u t h d u r i n g 2 s a m p l i n g t r i p s ) o f a p p r o x i m a t e l y 1 0 k m r a d i u s w e r e d e t e r m i n e d a t t h e l o c a t i o n s w h i c h i n c l u d e s s i t e s M 4, M 9 + M M 1 1, M M 1 3, M 5 + M 6, M 7 + M 8. I n t e r l a b o r a t o r y c o m p a r i s o n s b e t w e e n O C D D d e t e r m i n a t i o n a t E r g o a n d Q H S S l a b o r a t o r i e s f o r s a m p l e M 4 i s a l s o i n c l u d e d i n t h i s d a t a s e t. 3 2
34 C H A P T E R 2 SP A T I A L D I S T R I B U T I O N M Marine sediment sampling locations M1 I1-I2 T1 T2 T3 I3-I6 Townsville I Irrigation sediment sampling locations M2 M3 M4 T Topsoil sampling locations Sugar cane growing area Cotton growing area Urban areas M5 M6 M7 M8 M9 M10 M11 M12 M13 M14 M15 M16 M17 M18 M19 a M20 M21 M22 I7-I11 Brisbane a M23 a M24 a Samples reported by Mü ller et al. (1999a) FIGURE 2.1 M A P O F Q UEENSLAND, A USTRALIA SHOWING SAM P L I N G S I T E S, A P P R O X I M A T E L O C A T I O N S O F S U G A R C A N E A N D C O T T ON GROWING AREAS, AS WELL AS MAJOR URBA N C E N T E R S 3 3
35 C H A P T E R 2 SP A T I A L D I S T R I B U T I O N ORGANIC CARBON T o t a l o r g a n i c c a r b o n ( T O C ) w a s d e t e r m i n e d a t t h e Q H S S l a b o r a t o r y a c c o r d i n g t o a s t a n d a r d i s e d p r o c e d u r e ( Q u e e n s l a n d H e a l t h S c i e n t i f i c S e r v i c e s ). I n o r g a n i c c a r b o n a t e s w e r e r e m o v e d u s i n g a c i d c a t a l y s e d d i g e s t i o n ( 1 0 % H C l, 1 % F e C l 2 a t 7 0 o C). T h e r e m a i n i n g m a t e r i a l w a s d r i e d a n d c o m b u s t e d i n t h e L E C O i n d u c t i o n f u r n a c e w i t h s u b s e q u e n t d e t e c t i o n o f C O 2. ( L E C O W R 1 2 C O 2 d e t e c t o r ). 2.3 RESULTS AND DISCUSSION REPRODUCIBILITY T h e r e p r o d u c i b i l i t y w a s t e s t e d u s i n g O C D D r e s u l t s ( n o r m a l i s e d t o T O C ). T h e c o e f f i c i e n t o f v a r i a n c e a v e r a g e d 3 4 % ( r a n g e 3 % t o 7 9 % ), 4 3 % ( r a n g e 1 4 % t o 7 2 % ) a n d 4 7 % ( r a n g e 5 % t o 7 6 % ) i n a n a l y t i c a l, s a m p l i n g a n d s p a t i a l p l u s t e m p o r a l r e p l i c a t e s a m p l e s, r e s p e c t i v e l y. A n o b s e r v e d l o w e r a n a l y t i c a l v a r i a b i l i t y i n s e d i m e n t s w i t h h i g h O C D D c o n c e n t r a t i o n s i s c o n s i s t e n t w i t h r e s u l t s r e p o r t e d b y ( P e t t e r s e n e t a l ). H i g h e s t s p a t i a l p l u s t e m p o r a l v a r i a b i l i t y o f O C D D w a s f o u n d i n l o c a t i o n s t h a t i n c l u d e d r i v e r m o u t h s i t e s, i n d i c a t i n g l e s s h o m o g e n o u s d i s t r i b u t i o n o f O C D D i n t h e m o r e variab l e e n v i r o n m e n t o f r i v e r i n e i n f l u e n c e d s i t e s. T h i s i s a l s o d e m o n s t r a t e d b y a n a m p l i f i c a t i o n o f s p a t i a l a n d s a m p l i n g r e l a t e d v a r i a b i l i t y w h e n O C D D c o n c e n t r a t i o n s a r e n o r m a l i s e d t o d r y w e i g h t c o m p a r e d t o T O C n o r m a l i s e d c o n c e n t r a t i o n s MARINE SEDIMENTS T h e co n c e n t r a t i o n s o f O C D D i n m a r i n e s e d i m e n t s, e x p r e s s e d o n b o t h a d r y w e i g h t a n d o r g a n i c c a r b o n b a s i s a r e s h o w n i n F i g u r e O C D D c o n c e n t r a t i o n s r a n g e d f r o m 1 4 ng g -1 T O C a t t h e c o n t r o l s i t e M 1 a n d s i t e M 1 5 t o n g g - 1 T O C a t s i t e M 2 w i t h a m e d i a n v a l u e o f n g g - 1 T O C. R e l a t i v e l y l o w c o n c e n t r a t i o n s, c o m p a r a b l e t o t h o s e i n t h e c o n t r o l s i t e w e r e a l s o d e t e c t e d a t s i t e s M 1 1, M 1 5, M 1 7 a n d M 2 0. O f t h e s e s i t e s, M 1 5 a n d M 1 7 a r e l o c a t e d n e a r t h e u r b a n c e n t r e T o w n s v i l l e. O C D D c o n c e n t r a t i o n s i n m a r i n e s e d i m e n t s c o l l e c t e d i n t h e w e t t r o p i c s ( M 2-M 1 4 ) w e r e e l e v a t e d c o m p a r e d t o t h e s e s i t e s. I n p a r t i c u l a r s a m p l e s c o l l e c t e d n e a r t h e m o u t h o f r i v e r s i n t h i s a r e a ( i. e. M 2- M 4, M 1 3 ) s h o w e d h i g h l e v e l s r a n g i n g f r o m n g g - 1 T O C t o n g g - 1 T O C. W i t h r e s p e c t t o O C D D c o n c e n t r a t i o n s, s e d i m e n t s f r o m t h e s e n o r t h e r n r i v e r s i t e s w e r e 3 4
36 C H A P T E R 2 SP A T I A L D I S T R I B U T I O N c o m p a r a b l e t o s e d i m e n t s f r o m t h e m o u t h o f t h e B r i s b a n e R i v e r ( M 2 3 ) a n d M o r e t o n B a y ( M 2 4 ), b o t h o f w h i c h r e c e i v e r u n-o f f f r o m t h e B r i s b a n e m e t r o p o l i t a n a r e a. O C D D c o n c e n t r a t i o n s i n s e d i m e n t s f r o m t h e d e s i g n a t e d c o n t r o l s i t e M 1 w e r e r e l a t i v e l y h i g h w h e n c o m p a r e d t o O C D D c o n c e n t r a t i o n s i n s e d i m e n t s c o l l e c t e d f r o m o t h e r r e m o t e a r e a s i n A u s t r a l i a ( M o s s e a n d H a y n e s ) o r s e d i m e n t s f r o m s u b a r c t i c F i n l a n d ( V a r t i a i n e n e t a l ). F u r t h e r m o r e, O C D D c o n c e n t r a t i o n i n s e d i m e n t s f r o m a n u m b e r o f m a r i n e s i t e s e x c e e d e d t h e m a j o r i t y o f O C D D c o n c e n t r a t i o n s i n s e d i m e n t s r e p o r t e d f r o m o t h e r r e l a t i v e l y p o l l u t e d r i v e r s s u c h a s t h e r i v e r E l b e i n G e r m a n y ( O C D D r a n g i n g f r o m t o p g g -1 d w, m e d i a n : p g g - 1 d w ) (Schramm et al ) a n d t h e H o u s a t o n i c R i v e r n e a r N e w Y o r k ( O C D D r a n g i n g f r o m 8 6 t o 2 0, p g g -1 d w, m e d i a n : p g g - 1 d w ) ( E i t z e r ). A c c o r d i n g t o t h e c a t e g o r i s a t i o n o f P C D D / F c o n t a m i n a t i o n i n s e d i m e n t s a m p l e s s u g g e s t e d b y ( H o l o u b e k e t a l ), t h e s e d i m e n t s f r o m m a j o r r i v e r p l u m e s i n Q u e e n s l a n d f a l l i n t o t h e c a t e g o r y p o l l u t e d t o h e a v i l y p o l l u t e d TERRESTRIAL TOPSOIL AND IRRIGATION DRAIN SEDIMENTS I n a d d i t i o n t o t h e m a r i n e s e d i m e n t s, 3 t o p s o i l s a m p l e s, c o l l e c t e d i n a m a j o r c a t c h m e n t o f t h e w e t t r o p i c s w e r e a n a l y s e d. P r e v i o u s r e s u l t s f r o m t o p s o i l a n a l y s e d f r o m t h i s a r e a a s w e l l a s m a r i n e s e d i m e n t s c o l l e c t e d i n t h e v i c i n i t y o f t h e m a j o r r i v e r d r a i n i n g t h i s c a t c h m e n t ( n e a r M 1 2 a n d M 1 3 ) i n d i c a t e d t h a t a P C D D s o u r c e m a y e x i s t ( o r h a s e x i s t e d ) i n t h i s a r e a ( M ü l l e r e t a l c ). I n t h e p r e s e n t s t u d y O C D D c o n c e n t r a t i o n s w e r e f o u n d t o b e u p t o t h r e e t i m e s h i g h e r i n t o p s o i l f r o m t h e s u g a r c a n e f a r m ( T 1, 6 2 n g g - 1 T O C ) c o m p a r e d w i t h t o p s o i l s a m p l e s c o l l e c t e d f r o m t h e u n c u l t i v a t e d p a d d o c k ( T 2, 1 9 ng g - 1 T O C ) a n d t h e N a t i o n a l P a r k ( T 3, 1 9 n g g - 1 T O C ) ( F i g u r e 2. 3 ). O C D D c o n c e n t r a t i o n i n t h e s a m p l e T 1 w a s a l s o r e l a t i v e l y h i g h w h e n c o m p a r e d t o r e s u l t s o n c u l t i v a t e d s o i l f r o m f o r e x a m p l e G e r m a n p l o w l a n d ( m e d i a n O C D D c o n c e n t r a t i o n pg g - 1 d w ) ( R o t a r d e t a l ), o r e v e n f r o m s u g a r c a n e f a r m s i n B r a z i l a n d S o u t h A f r i c a ( O C D D c o n c e n t r a t i o n 8 p g g - 1 d w a n d 3 3 p g g - 1 dw, respectively) ( P ä p k e ). T o f u r t h e r i n v e s t i g a t e p o s s i b l e s o u r c e s r e l a t e d t o a g r i c u l t u r a l a c t i v i t i e s, s e d i m e n t s a m p l e s f r o m d r a i n s l o c a t e d i n a r e a s w h i c h a r e d o m i n a t e d b y e i t h e r s u g a r c a n e o r c o t t o n w e r e a n a l y s e d f o r O C D D. C o n s i d e r a b l y h i g h e r O C D D c o n c e n t r a t i o n s i n i r r i g a t i o n d r a i n sediments from sugar cane areas (S1 -S 6, m e d i a n p g g - 1 T O C, r a n g e 5 3 n g g - 1 T O C t o n g g - 1 T O C ) c o m p a r e d t o t h o s e f r o m c o t t o n a r e a s ( S 7 -S 1 1, m e d i a n 1 1 p g g
37 C H A P T E R 2 SP A T I A L D I S T R I B U T I O N OCDD concentration [ng g -1 TOC] M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11 M12 M13 M14 M15 M16 M17 M18 M19 a M20 M21 M22 OCDD [pg/g dw] OCDD [ng/g TOC] a M23 a M OCDD concentration [pg g -1 dw] a R e s u l t s f r o m ( M ü l l e r e t a l b ) FIGURE 2.2 O C D D C O N C E N T R A T I O N S (NG G - 1 T O C AND PG G - 1 DW ) IN MARINE S E D I M E N T S F R O M Q UEENSLAND. 3 6
38 C H A P T E R 2 SP A T I A L D I S T R I B U T I O N OCDD concentration [ng g -1 TOC] T1 T2 T3 OCDD [pg/g dw] OCDD [ng/g TOC] OCDD concentration [pg g -1 dw] FIGURE 2.3 O C D D C O N C E N T R A T I O N S (N G G -1 T O C A N D P G G -1 D W) I N T O P S O I L F R O M Q UEENSLAND. T O C, r a n g e n. d. t o 4 8 n g g -1 T O C ) w e r e o b s e r v e d ( F i g u r e 2. 4 ). O C D D c o n c e n t r a t i o n s i n s e d i m e n t s c o l l e c t e d f r o m c o t t o n d r a i n s w e r e o n a v e r a g e e v e n l o w e r t h a n i n s e d i m e n t s f r o m t h e m a r i n e c o n t r o l s i t e M 1. I n c o n t r a s t, a s e p a r a t e s t u d y f o u n d r e l a t i v e l y h i g h c o n c e n t r a t i o n s o f v a r i o u s o r g a n o c h l o r i n e c h e m i c a l s s u c h a s e n d o s u l f a n, D D E o r d i e l d r i n i n t h e s e d i m e n t s f r o m t h e i r r i g a t i o n d r a i n s i n c o t t o n g r o w i n g a r e a s, w h i l e t h e l e v e l s o f t h e s e c o m p o u n d s w e r e m u c h l o w e r i n t h e s e d i m e n t s d r a i n s f r o m sugar cane growing areas ( M ü l l e r e t a l ). W i t h r e g a r d t o P C D D / F c o n c e n t r a t i o n, a n d e v e n o n l y o n t h e b a s i s o f O C D D c o n c e n t r a t i o n s, s u g a r c a n e d r a i n s e d i m e n t s f a l l i n t o t h e c a t e g o r i e s s l i g h t l y p o l l u t e d t o v e r y h e a v i l y p o l l u t e d ( H o l o u b e k e t a l ) SOURCES T h e c o n g e n e r p r o f i l e s i n a l l s a m p l e s a n a l y s e d w e r e d o m i n a t e d b y h i g h e r c h l o r i n a t e d P C D D s, i n p a r t i c u l a r O C D D ( F i g u r e 2. 5 ), w h i c h c o n t r i b u t e d 7 0 % t o 9 3 % t o t h e t o t a l P C D D / F c o n c e n t r a t i o n. C o n c e n t r a t i o n s o f 2, 3, 7, 8 -s u b s t i t u t e d d i b e n z o f u r a n s w e r e v e r y l o w a n d m o s t l y b e l o w t h e l i m i t o f d e t e c t i o n ( T a b l e 2. 1 ). 2, 3, 7, 8 -T C D D w a s b e l o w t h e d e t e c t i o n l i m i t o r n o t q u a n t i f i a b l e i n a n y o f t h e s e d i m e n t s o r s o i l s a n a l y s e d a n d t h e p r o f i l e i n c r e a s e d f r o m l o w e r t o h i g h e r c h l o r i n a t e d P C D D s ( F i g u r e 2. 5 ). M a r i n e s e d i m e n t s, a g r i c u l t u r a l s o i l a n d d u g o n g b l u b b e r s a m p l e s p r e v i o u sly analysed from sites i n N o r t h Q u e e n s l a n d a l l s h o w s t r o n g s i m i l a r i t i e s t o s a m p l e s c o l l e c t e d d u r i n g t h e p r e s e n t s t u d y. A s i m i l a r p r o f i l e w a s a l s o f o u n d i n a s a m p l e f r o m M o r e t o n B a y ( M 2 3 ), w h i c h receives run -o f f f r o m t h e B r i s b a n e m e t r o p o l i t a n a r e a. H o w e v e r, a t t h e m o u t h o f t h e B r i s b a n e r i v e r ( M 2 4 ) a n d f u r t h e r u p r i v e r ( d a t a n o t p r e s e n t e d ), P C D F s a s w e l l a s 2, 3, 7, 8-3 7
39 C H A P T E R 2 SP A T I A L D I S T R I B U T I O N OCDD concentration [ng g -1 TOC] I1 I2 I3 I4 I5 I6 I7 I8 I9 I10 OCDD [pg/g dw] OCDD [ng/g TOC] I OCDD concentration [pg g -1 dw] FIGURE 2.4 O C D D C O N C E N T R A T I O N S (NG G - 1 T O C AND PG G - 1 DW ) IN IRRIGATION D R A I N S E D I M E N T S F R O M Q UEENSLAND. T C D D w e r e d e t e c t a b l e ( M ü l l e r e t a l c ). T h e s i m i l a r i t i e s i n P C D D / F c o n g e n e r p r o f i l e s s u g g e s t t h a t t h e P C D D s o u r c e o r f o r m a t i o n p r o c e s s i s s i m i l a r f o r a l l samples. T h i s i s r e m a r k a b l e c o n s i d e r i n g t h a t o v e r a l l t h e s e s a m p l e s h a v e b e e n c o l l e c t e d a l o n g a c o a s t l i n e r e p r e s e n t i n g a p p r o x i m a t e l y k m d i s t a n c e f r o m s o u t h t o n o r t h w i t h a v a r i e t y o f a n t h r o p o g e n i c a n d t e r r e s t r i a l i n f l u e n c e s. P C D D / F p r o f i l e s c h a r a c t e ri s e d b y a d o m i n a t i o n o f h i g h e r c h l o r i n a t e d d i o x i n s a n d l o w P C D F l e v e l s h a v e b e e n f o u n d i n a i r s a m p l e s c o n s i d e r e d t o b e b a c k g r o u n d. S t u d i e s o n a t m o s p h e r i c d e p o s i t i o n f u r t h e r s u g g e s t t h a t O C D D d e p o s i t i o n i s m o r e e f f e c t i v e t h a n d e p o s i t i o n o f a l l o t h e r P C D D/Fs ( K o e s t e r a n d H i t e s ; E i t z e r ; T y s k l i n d e t a l ), r e s u l t i n g i n a s h i f t t o w a r d s O C D D i n c o n g e n e r p r o f i l e s f r o m e n v i r o n m e n t s i n f l u e n c e d b y s u c h d e p o s i t i o n a l p r o c e s s e s. D e p o s i t i o n o f a t m o s p h e r i c P C D D / F s, w h i c h h a v e b e e n s u b j e c t t o l o n g -r a n g e t r a n s p o r t, i s u n l i k e l y t o c a u s e t h e o b s e rv e d d i f f e r e n c e s 3 8
40 C H A P T E R 2 SP A T I A L D I S T R I B U T I O N i n P C D D / F l e v e l s, p a r t i c u l a r i n c u l t i v a t e d s o i l s c o m p a r e d t o f o r e s t s o i l s, a n d t h e r e f o r e s e e m s a n u n l i k e l y s o u r c e / p a t h w a y f o r O C D D i n Q u e e n s l a n d Concentration [pg g -1 ] dw TCDD PeCDD HxCDD HxCDD HxCDD a HpCDD OCDD TCDF PeCDF PeCDF b HxCDF HxCDF HxCDF HxCDF HpCDF HpCDF OCDF FIGURE 2.5 T Y P I C A L P C D D / F CONGENER PROFILE IN M A R I N E S E D I M E N T S A N D T O P S O I L F R O M Q UEENSLAND. C o n g e n e r p r o f i l e s d o m i n a t e d b y O C D D h a v e a l s o b e e n r e p o r t e d a s a r e s u l t o f a p p l i c a t i o n o f P C D D / F c o n t a m i n a t e d p e n t a c h l o r o p h e n o l ( P C P ) ( H a g e n m a i e r a n d B r u n n e r ; S a f e e t a l ). H o w e v e r, P C P p r o f i l e s a r e g e n e r a l l y c h a r a c t e r i s e d b y h i g h e r c o n c e n t r a t i o n s o f P C D F s a n d t h e r a t i o o f t h e Σ P C D D t o Σ P C D F c o n c e n t r a t i o n s ( D / F r a t i o ) r a n g e s f r o m ( H a g e n m a i e r a n d B r u n n e r ; W H O / I P C S ). F u r t h e r, 1, 2, 3, 6, 7, 8 -H x C D D i s u s u a l l y p r e s e n t a s t h e d o m i n a n t i s o m e r a m o n g t h e t o x i c H x C D D s i n P C P ( H a g e n m a i e r a n d B r u n n e r ; G i f f o r d e t a l ). T h i s c o n t r a s t s t o r e s u l t s f r o m t h e p r e s e n t s t u d y w h e r e D / F r a t i o s w e r e f o u n d t o b e c o n s i d e r a b l y h i g h e r, ranging f r o m > 3 0 t o > w i t h a m e d i a n D / F r a t i o o f ( T a b l e 2. 1 ), a n d t h e 1, 2, 3, 7, 8, 9 -H x C D D / 1, 2, 3, 4, 6, 7 -H x C D D i s o m e r p a i r w a s f o u n d t o d o m i n a t e a m o n g t h e 2, 3, 7, 8 -s u b s t i t u t e d H x C D D s i n s e d i m e n t s a n d s o i l s f r o m Q u e e n s l a n d ( F i g u r e 2. 6 A a n d 2. 6 C ). 3 9
41 C H A P T E R 2 SP A T I A L D I S T R I B U T I O N O n t h e o t h e r h a n d, P C D D / F p r o f i l e s f o u n d i n t h i s s t u d y a r e s i m i l a r t o t h o s e r e p o r t e d i n s e d i m e n t s c o l l e c t e d f r o m t h e Y e l l o w S e a, t h e E a s t C h i n a S e a a n d t h e P a c i f i c O c e a n ( H a s h i m o t o e t a l ). D o m i n a n c e o f h i g h e r c h l o r i n a t e d P C D D s a n d s i m i l a r H x C D D i s o m e r p a t t e r n s w e r e a l s o r e c o r d e d f r o m b a l l c l a y i n t h e U S ( R a p p e e t a l b ) a n d k a o l i n i t e i n G ermany ( J o b s t a n d A l d a g ; P ä p k e ) (Figure 2.6 B). Further, s e d i m e n t s f r o m t h e L e a f -P a s c a g o u l a R i v e r s y s t e m a n d l a k e s f r o m t h e s o u t h e r n M i s s i s s i p p i ( R a p p e e t a l a ) d e m o n s t r a t e d a l s o s i m i l a r O C D D d o m i n a n c e, a s w e l l a s c o m p a r a b l e O C D D c o n c e n t r a t i o n s, h i g h D / F r a t i o s a n d a l m o s t i d e n t i c a l H x C D D i s o m e r p a t t e r n s. B e s i d e s t h e s i m i l a r p r o f i l e s, t h e s e e x a m p l e s h a v e i n c o m m o n t h a t o b v i o u s a n t h r o p o g e n i c s o u r c e s a r e n o t e v i d e n t. A l t h o u g h h i g h e r c o n c e n t r a t i o n s o f O C D D w e r e a s s o c i a t e d w i t h c u l t i v a t e d s o i l s i n n o r t h e r n Q u e e n s l a n d, e s p e c i a l l y s u g a r c a n e c u l t i v a t i o n, n o p r o c e s s h a s y e t b e e n i d e n t i f i e d w h i c h l i n k s t h i s t y p e o f l a n d-u s e t o t h e o b s e r v e d P C D D c o n t a m i n a t i o n. N a t u r a l f o r m a t i o n p r o c e s s e s h a v e r e c e i v e d i n c r e a s e d a t t e n t i o n. E v i d e n c e t h a t b i o g e n i c f o r m a t i o n o f p a r t i c u l a r l y t h e h i g h e r c h l o r i n a t e d P C D D o c c u r s h a s b e e n f o u n d i n a r a n g e o f s t u d i e s ( Ö b e r g e t a l ; W i t t s i e p e e t a l ). A l s o, g e o g e n i c f o r m a t i o n p r o c e s s e s h a v e b e e n s u s p e c t e d a s a p o t e n t i a l s o u r c e w h i c h h a s r e s u l t e d i n O C D D c o n t a m i n a t i o n o f k a o l i n i t e c l a y u s e d f o r a n i m a l f e e d i n G e r m a n y ( J o b s t a n d A l d a g ; P ä p k e b ). A l t e r n a t i v e f o r m a t i o n p r o c e s s e s h a v e b e e n s u g g e s t e d t o b e a p o s s i b l e s o u r c e r e s u l t i n g i n t h e u n u s u a l P C D D / F p r o f i l e s a n d h i g h O C D D c o n c e n t r a t i o n s f o u n d i n t h e M i s s i s s i p p i a r e a ( R a p p e e t a l a ; b ). T h e p a r t i c u l a r e n v i r o n m e n t a l c o n d i t i o n s w h i c h a r e s u i t a b l e t o c u l t i v a t e s u g a r c a n e i n Q u e e n s l a n d ( e. g. c l i m a t e, s o i l t y p e, g e o l o g i c a l h i s t o r y ) m a y t h e r e f o r e a l s o f a v o u r p r o c e s s e s w h i c h r e s u l t o r h a v e r e s u l t e d i n t h e f o r m a t i o n o f h i g h e r c h l o r i n a t e d P C D D s. 2.4 CONCLUSIONS P C D D / F a n a l y s i s o f m a r i n e s e d i m e n t s, i r r i g a t i o n d r a i n s e d i m e n t s a n d t o p s o i l f r o m Q u e e n s l a n d c l e a r l y i n d i c a t e t h a t a s o u r c e f o r P C D D s e x i s t s o r h a s e x i s t e d i n t h e s e a r e a s. R e l a t i v e l y h i g h O C D D c o n c e n t r a t i o n s i n m a r i n e a n d d r a i n s e d i m e n t s, a s w e l l a s s o i l f r o m v a r i o u s r e g i o n s i n f l u e n ce d b y a r e a s, d o m i n a t e d b y e i t h e r s u g a r c a n e, c o t t o n, o r u r b a n a r e a s a n d i n c l u d i n g a r e m o t e l o c a t i o n, s u g g e s t t h e s o u r c e t o b e o f s i g n i f i c a n c e. F u r t h e r, a l m o s t i d e n t i c a l c o n g e n e r p r o f i l e s a n d i s o m e r p a t t e r n s i n m a r i n e s e d i m e n t s a s 4 0
42 TABLE 2.1 C O N C E N T R A T I O N S O F 2, 3, 7, 8 -S U B S T I T U T E D P C D D / F S A N D S U M O F I S O M E R S I N H O M O L O G U E S (IN NG G - 1 T O C (L E F T C O L U M N S ) A N D P G G - 1 DW (R I G H T C O L U M N S )) AND % T O C F O R M A R I N E S E D I M E N T S A N D T O P S O I L S A M P L E S. Marine sediments Topsoil M4 M5 M6 M7 M8 M10 M12 M14 M16 T1 T2 %TOC Tetra-CDD n.d. n.d. < < 0.16 < < 0.28 n.d. n.d. < < 0.13 < < 0.13 n.d. n.d. n.d. n.d. total Tetra-CDD n.d. n.d Penta-CDD < 0.10 < < 0.16 < 0.43 < < 0.36 n.d. n.d. n.d. n.d. total Penta-CDD < 0.33 < Hexa-CDD < 0.19 < n.d. n.d. < < Hexa-CDD n.d. n.d. < 0.10 < Hexa-CDD a n.d. n.d total Hexa-CDD < 3.4 < Hepta-CDD < 1.8 < total Hepta-CDD OCDD Tetra-CDF < < 0.22 < < 0.25 < < < < 0.21 < < 0.16 < 0.27 < 0.17 < < 0.13 total Tetra-CDF < < < 0.10 < Penta-CDF < < n.d. n.d. n.d. n.d. < < n.d. n.d. < < n.d. n.d. n.d. n.d Penta-CDF b n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. total Penta-CDF < < n.d. n.d. n.d. n.d. < < < < 0.33 n.d. n.d. < < Hexa-CDF n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d Hexa-CDF n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. < < 0.12 n.d. n.d. n.d. n.d. n.d. n.d Hexa-CDF n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d Hexa-CDF < < 0.17 < < 0.18 < < 0.29 < < 0.11 < 0.12 < 0.33 < < 0.32 < 0.17 < 0.11 < < 0.27 total Hexa-CDF < < 0.17 < < 0.18 < < 0.29 < < 0.11 < 0.79 < 2.2 < 0.29 < 1.7 < 0.17 < 0.11 < 0.26 < Hepta-CDF < < 0.12 n.d. n.d. n.d. n.d. < < < 0.28 < 0.78 < 0.12 < 0.74 n.d. n.d. < 0.33 < Hepta-CDF n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. < 0.14 < 0.39 < < 0.20 n.d. n.d. n.d. n.d. total Hepta-CDF < < 0.12 n.d. n.d. n.d. n.d. < < < 0.85 < 2.3 < 0.29 < 1.7 n.d. n.d. < 0.55 < 1.9 OCDF n.d. n.d. n.d. n.d. n.d. n.d. < < 0.51 < 1.3 < 3.6 < 0.39 < 2.4 n.d. n.d. < 1.1 < 3.9 total PCDD total PCDF total PCDD/PCDF I-TEQ < < 0.08 n.d. n.d. < < < < 0.26 < < 0.19 n.d. n.d n.d. n.d <0.006 < < < < < 0.19 < < 0.32 < < < < 0.14 < < < < n.d. n.d. < < n.d. n.d < < n.d. n.d. < < < < < < 0.08 < < n.d. n.d. n.d. n.d. n.d. n.d. < < < < 0.19 < < 0.13 < < 0.15 < 0.57 < 1.5 < < 0.79 < < 0.31 < 0.52 < 1.3 n.d. n.d. < < 0.14 < 0.17 < 0.45 n.d. n.d < 1.1 < 3.0 n.d. n.d. < < 0.73 < 2.3 < 6.0 < < 0.37 < < PCDD:PCDF (D/F) ratio n.d. - not detectable, detection limit: pg g -1 dw < - not quantifiable a coeluted with Hexa-CDD b coeluted with Penta-CDF
43 C H A P T E R 2 SP A T I A L D I S T R I B U T I O N 1, 2, 4, 6,7,9 1,2,4, 6, 8, 9 1, 2, 3,4,6,8 1,2, 3,6,7, 9 1,2, 3,6,8, 9 1, 2, 3,4,6,9 1, 2,3,4,7, 8 1, 2, 3,6,7,8 1,2, 3, 7, 8,9 1, 2, 3, 4, 6,7 A B C FIGURE 2.6 H E X A-C D D I S O M E R P A T T E R N F R O M A T Y P I C A L S A M P L E F R O M Q UEENSLAND (A), KAOLINITE CLAY (B) A N D P E N T A C H L O R O P H E N O L (C). 4 2
44 C H A P T E R 2 SP A T I A L D I S T R I B U T I O N w e l l a s s o i l f r o m v a r i o u s r e g i o n s i n d i c a t e a s i m i l a r s o u r c e t h a t i s w i d e s p r e a d a n d m o s t l i k e l y l a n d -b a s e d. D o m i n a n c e o f h i g h e r c h l o r i n a t e d P C D D s, i n p a r t i c u l a r O C D D, h i g h D / F r a t i o s a n d d o m i n a n c e o f t h e 1, 2, 3, 7, 8, 9 -H x C D D / 1, 2, 3, 4, 6, 7 -H x C D D i s o m e r p a i r c h a r a c t e r i s e P C D D / F p r o f i l e s a n d p a t t e r n s. T h i s r e p r e s e n t s a r a t h e r u n u s u a l c o n g e n e r p r o f i l e t h a t c o u l d n o t b e r e l a t e d t o a m a j o r t e c h n i c a l o r i n d u s t r i a l P C D D / F s o u r c e k n o w n t o d a y. H o w e v e r, s t r o n g s i m i l a r i t i e s t o s e d i m e n t s a n d so i l i n Q u e e n s l a n d w i t h r e s p e c t t o c o n g e n e r p r o f i l e s a n d i s o m e r p a t t e r n s h a v e b e e n r e c o r d e d i n s e d i m e n t s a n d b a l l c l a y f r o m t h e U S a s w e l l a s k a o l i n i t e f r o m G e r m a n y. T h i s m a y s u g g e s t t h e p o s s i b i l i t y o f a s i m i l a r, p o t e n t i a l l y n a t u r a l s o u r c e t h a t i s y e t u n i d e n t i f i e d. T h e p r o c e s s o r p r o c e s s e s t h a t h a v e r e s u l t e d i n t h i s w i d e s p r e a d c o n t a m i n a t i o n w i t h P C D D s i n Q u e e n s l a n d r e m a i n, h o w e v e r, u n c l e a r a t t h i s s t a g e. 4 3
45 CHAPTER 3 TEMPORAL PCDD/F DISTRIBUTION IN QUEENSLAND Natural formation? In parts published in: Environmental Science and Technology 2001 (Volume 35, pages ); Organohalogen Compounds 2000 (Volume 46, pages )
46 Some material in this chapter was published in the article Caroline Gaus (et al.). Historical PCDD Inputs and Their Source Implications from Dated Sediment Cores in Queensland (Australia), Environmental Science & Technology vol. 35 (2001), pp Reproduced in part with permission from American Chemical Society. Copyright 2001 American Chemical Society.
47 C H A P T E R 3 T E M P O R A L D I S T R I B U T I O N ABSTRACT S t u d i e s i n t h e c o a s t a l z o n e o f Q u e e n s l a n d ( A u s t r a l i a ) h a v e d e m o n s t r a t e d t h e p r e s e n c e o f a n u n i d e n t i f i e d s o u r c e o f p o l y c h l o r i n a t e d d i benzo -p -d i o x i n s ( P C D D s ). T h e p r e s e n t s t u d y p r o v i d e s n e w i n f o r m a t i o n o n t h e p o s s i b l e P C D D s o u r c e s a n d t h e i r t e m p o r a l i n p u t t o t h i s e n v i r o n m e n t. T w o e s t u a r i n e s e d i m e n t c o r e s w e r e c o l l e c t e d i n n o r t h e r n Q u e e n s l a n d f o r w h i c h r a d i o c h e m i c a l c h r o n o l o g i e s w e r e e s t a b l i s h e d. C o r e s e c t i o n s f r o m d i f f e r e n t d e p o s i t i o n a l a g e s, u p t o t h r e e c e n t u r i e s h a v e b e e n a n a l y s e d f o r 2, 3, 7, 8 - s u b s t i t u t e d P C D D s a n d p o l y c h l o r i n a t e d d i b e n z o f u r a n s ( P C D F s ). V a r i a t i o n s o f P C D D c o n c e n t r a t i o n s i n t h e s e d i m e n t c o r e s o v e r s e v e r a l c e n t u r i e s o f d e p o s i t i o n a l h i s t o r y w e r e r e l a t i v e l y s m a l l, a n d e l e v a t e d P C D D l e v e l s w e r e s t i l l p r e s e n t i n s e d i m e n t s l i c e s f r o m t h e early 17 th c e n t u r y. P C D D / F i s o m e r p a t t e r n s a n d c o n g e n e r p r o f i l e s i n s e d i m e n t s d e p o s i t e d d u r i n g t h e l a s t y e a r s w e r e a l m o s t i d e n t i c a l a n d c o r r e l a t e d w e l l t o t h e c h a r a c t e r i s t i c p r o f i l e s o b s e r v e d i n s u r f a c e s e d i m e n t s a n d s o i l s f r o m t h e e n t i r e Q u e e n s l a n d c o a s t l i n e. P r o f i l e s w e r e d o m i n a t e d b y h i g h e r c h l o r i n a t e d P C D D s, i n p a r t i c u l a r o c t a c h l o r o d i b e n z o d i o x i n ( O C D D ), w h e r e a s P C D F c o n c e n t r a t i o n s w e r e b e l o w o r n e a r t h e l i m i t o f d e t e c t i o n. T h e s e r e s u l t s i n d i c a t e t h e p r e s e n c e o f a P C D D s o u r c e p r i o r t o i n d u s t r i a l i s a t i o n a n d p r o d u c t i o n o f c o m m e r c i a l o r g a n o c h l o r i n e p r o d u c t s. F u r t h e r, t h e p r e s e n t s t u d y s u g g e s t s t h a t P C D D i n p u t p a t t e r n s m a y h a v e b e e n s i m i l a r a l o n g a n e x t e n s i v e b u t l o c a l i s e d a r e a o v e r a t l e a s t s e v e r a l c e n t u r i e s, c o n t r i b u t i n g r e l a t i v e l y h i g h c o n c e n t r a t i o n s o f P C D D s t o t h e c o a s t a l s y s t e m o f Q u e e n s l a n d. 4 5
48 C H A P T E R 3 T E M P O R A L D I S T R I B U T I O N 3.1 INTRODUCTION T h e p r i m a r y s o u r c e s o f p o l y c h l o r i n a t e d d i b e n z o -p -d i o x i n s a n d d i b e n z o f u r a n s (P C D D / F s ) h a v e b e e n i d e n t i f i e d i n m a n y c o u n t r i e s a s c o m b u s t i o n p r o c e s s e s s u c h a s m u n i c i p a l w a s t e i n c i n e r a t i o n a n d v a r i o u s c h e m i c a l p r o c e s s e s t h a t r e s u l t i n c o n t a m i n a t e d p r o d u c t s a n d w a s t e ( U. S. E P A ; U N E P ). T h e s u b s e q u e n t e m i s s i o n t o t h e a t m o s p h e r e r e n d e r s t h e s e c o m p o u n d s u b i q u i t o u s i n t h e c o n t e m p o r a r y e n v i r o n m e n t a n d r e s u l t i n a n e n v i r o n m e n t a l b a s e l i n e P C D D / F b u r d e n ( C z u c z w a a n d H i t e s ; T y s k l i n d e t a l ). T h e r e f o r e, s i n k a r e a s s u c h a s m a r i n e e c o s y s t e m s t h a t a r e d i s t a n t f r o m a n t h r o p o g e n i c P C D D / F s o u r c e s m a y b e c o n t a m i n a t e d w i t h l o w b a c k g r o u n d P C D D / F l e v e l s. H o w e v e r, d u r i n g t h e l a s t d e c a d e a l a r g e n u m b e r o f s t u d i e s h a v e i n d i c a t e d t h a t n o n- a n t h r o p o g e n i c P C D D / F s o u r c e s a r e p r e s e n t i n t h e e n v i r o n m e n t (e.g. Chapter 3, Prange e t a l b ; R a p p e e t a l a ; b ; K j e l l e r e t a l ; F e r r a r i o e t a l ; A l c o c k e t a l ; G r e e n e t a l ; N e s t r i c k e t a l ; H ö k s t r a e t a l ), w h i c h m a y p r o v i d e a n a t u r a l b a s e l i n e l e v e l o f t h e s e c o m p o u n d s i n s p e c i f i c l o c a t i o n s. F o r e x a m p l e, Q u e e n s l a n d, t h e n o r t h e a s t e r n s t a t e o f A u s t r a l i a, i s p r e d o m i n a n t l y r u r a l a n d k n o w n f o r i t s p r i s t i n e m a r i n e e n v i r o n m e n t s s u c h a s t h e G r e a t B a r r i e r R e e f. F e w i n d u s t r i a l P C D D / F s o u r c e s e x i s t i n t h e s e a r e a s a n d a s a c o n s e q u e n c e, o n l y l o w c o n t a m i n a n t c o n c e n t r a t i o n s w o u l d b e e x p e c t e d i n t h e e n v i r o n m e n t. R e c e n t s t u d i e s h a v e, h o w e v e r, d e m o n s t r a t e d t h e p r e s e n c e o f e l e v a t e d l e v e l s ( u p t o 3 0 n g g -1 d w ) o f h i g h e r c h l o r i n a t e d P C D D s i n m a r i n e s e d i m e n t s a n d t o p s o i l a l o n g t h e e n t i r e k m c o a s t l i n e o f Q u e e n s l a n d ( C h a p t e r 2 ; M ü l l e r e t a l b ; P r a n g e e t a l b ). R e m a r k a b l y, a l l s a m p l e s e x h i b i t e d s i m i l a r c o n g e n e r p r o f i l e s a n d i d e n t i c a l i s o m e r p a t t e r n s, c h a r a c t e r i s e d b y t h e d o m i n a n c e o f O C D D w h e r e a s P C D F c o n c e n t r a t i o n s w e r e n e a r o r b e l o w t h e l i m i t o f d e t e c t i o n. T h e s e r e s u l t s i n d i c a t e t h a t t h e P C D D s o urce is l a n d-b a s e d, h o w e v e r, t h e s p e c i f i c c o n g e n e r a n d i s o m e r p a t t e r n s c o u l d n o t b e a t t r i b u t e d t o k n o w n t e c h n i c a l o r i n d u s t r i a l P C D D / F s o u r c e s. S i m i l a r P C D D / F s i g n a t u r e s h a v e b e e n r e p o r t e d f r o m e l s e w h e r e i n s u r f a c e s e d i m e n t s, s o i l a n d k a o l i n c l a y ( R a p p e e t a l a ; b ; F e r r a r i o e t a l ; J o b s t a n d A l d a g ; G r e e n e t a l ). T h e a u t h o r s o f t h e s e s t u d i e s i n d i c a t e d t h a t i t i s u n l i k e l y t h a t a n t h r o p o g e n i c i n p u t s h a v e l e a d t o t h e o b s e r v e d c o n t a m i n a t i o n s a n d i t w a s s u g g e s t e d t h a t n a t u r a l p r o c e s s e s m a y b e i n v o l v e d i n P C D D / F f o r m a t i o n s i n t h e s e e n v i r o n m e n t s. 4 6
49 C H A P T E R 3 T E M P O R A L D I S T R I B U T I O N D a t e d s e d i m e n t c o r e s o r a r c h i v e d m a t e r i a l s h a v e b e e n u s e d t o p r o v i d e v a l u a b l e i n f o r m a t i o n o n t h e s i g n i f i c a n c e a n d o r i g i n o f h i s t o r i c a l a s w e l l a s m o r e r e c e n t P C D D / F i n p u t s ( K j e l l e r e t a l ; K j e l l e r a n d R a p p e ; H a g e n m a i e r a n d W a l c z o k ; K j e l l e r ). M o s t r e t r o s p e c t i v e P C D D / F i n f o r m a t i o n f r o m a r c h i v e d o r d a t e d d e p o s i t s i n d i c a t e s r e l a t i v e l y l o w l e v e l s o f P C D D / F s i n d e p o s i t s p r i o r t o t h e s. S u c h l o w a m b i e n t l e v e l s a r e t h e n t y p i c a l l y p r o c e e d e d b y s i g n i f i c a n t i n c r e a s e s i n P C D D / F c o n c e n t r a t i o n s t o g e t h e r w i t h c o n c u r r e n t c h a n g e s i n c o n g e n e r p r o f i l e s w i t h t h e o n s e t o f i n d u s t r i a l i s a t i o n a n d o r g a n o c h l o r i n e p r o d u c t i o n ( C z u c z w a a n d H i t e s ; K j e l l e r a n d R a p p e ; A l c o c k a n d J o n e s ; H a g e n m a i e r a n d W a l c z o k ). T h e s e s t u d i e s d e m o n s t r a t e t h a t t h e m a j o r c o n t r i b u t i n g s o u r c e s t o t h e c o n t e m p o r a r y P C D D / F b u r d e n a r e o f a n t h r o p o g e n i c o r i g i n. O n t h e o t h e r h a n d, r e l a t i v e l y h i g h P C D D l e v e l s ( i n p a r t i c u l a r O C D D ) h a v e b e e n r e p o r t e d i n d ee p s e d i m e n t c o r e s f r o m d e p o s i t s u p t o s e v e r a l t h o u s a n d ( p g g - 1 d w ) t o m i l l i o n ( p g g - 1 d w ) y e a r a g o f r o m J a p a n e s e c o a s t a l w a t e r s a n d t h e P a c i f i c O c e a n, r e s p e c t i v e l y (Hashimoto et al ; H a s h i m o t o e t a l ). S i m i l a r l y, r e l a t i v e l y h i g h c o n c e n t r a t i o n s o f m a i n l y O C D D (Σ P C D D / F c o n c e n t r a t i o n s u p t o p g g -1 d w ) h a v e b e e n r e p o r t e d i n t h e b o t t o m s t r a t a o f l a k e s e d i m e n t c o r e s f r o m M i s s i s s i p p i ( R a p p e e t a l b ). T he p r e s e n t s t u d y w a s c a r r i e d o u t t o d e t e r m i n e t h e t e m p o r a l d i s t r i b u t i o n o f P C D D / F s i n t h e Q u e e n s l a n d c o a s t a l e n v i r o n m e n t. C o n g e n e r s p e c i f i c P C D D / F a n a l y s i s w a s c a r r i e d o u t o n r a d i o c h e m i c a l d a t e d s e d i m e n t c o r e s f r o m d i f f e r e n t d e p o s i t i o n a l e r a s a n d r e g i o n s t o e v a l u a t e t h e h y p o t h e s i s t h a t t h e e x t e n s i v e P C D D c o n t a m i n a t i o n o f Q u e e n s l a n d m a y b e t h e c a u s e o f n o n -a n t h r o p o g e n i c p r o c e s s e s. S p e c i f i c a l l y, t h i s s t u d y w a s a i m e d t o a s s e s s w h e t h e r a ) t h e s p e c i f i c P C D D c o n t a m i n a t i o n i n t h e c o a s t a l e n v i r o n m e n t i s r e s t r i c t e d t o r e c e n t P C D D / F i n p u t s, i n d i c a t i n g a n t h r o p o g e n i c i n f l u e n c e s s i n c e E u r o p e a n s e t t l e m e n t a n d i n d u s t r i a l i s a t i o n, o r b ) p r e h i s t o r i c a l c o n t a m i n a t i o n w a s p r e s e n t i n Q u e e n s l a n d s e d i m e n t s a n d c a n p r o v i d e e v i d e n c e f o r t h e i n p u t o f n o n -a n t h r o p o g e n i c d e r i v e d PC D D s, a s w e l l a s f u r t h e r i n f o r m a t i o n o n t h e p o s s i b l e f o r m a t i o n p r o c e s s e s i n v o l v e d. 4 7
50 C H A P T E R 3 T E M P O R A L D I S T R I B U T I O N 3.2 MATERIALS AND METHODS LOCATION DESCRIPTION T w o e s t u a r i n e s e d i m e n t c o r e s ( A I M S a n d A I M S ) w e r e c o l l e c t e d i n t h e t r o p i c s o f N o r t h Q u e e n s l a n d, A u s t r a l i a ( F i g u r e 3. 1 ). C o r e ( H i n c h i n b r o o k ) w a s c o l l e c t e d f r o m a n i n t e r t i d a l m a n g r o v e m u d b a n k ( ' S; ' E) f r o m t h e H i n c h i n b r o o k C h a n n e l. T h i s a r e a r e c e i v e s t e r r i g e n o u s s e d i m e n t s f r o m t h e H e r b e r t R i v e r, w h i c h d r a i n s a w e t a n d d r y t r o p i c a l c a t c h m e n t o f a p p r o x i m a t e l y 1 0, k m 2 ( C S I R O ). C o r e ( B u r d e k i n ) w a s c o l l e c t e d i n B o w l i n g G r e e n B a y ( ' S; ' E ), a n e s t u a r i n e e m b a y m e n t t h a t r e c e i v e s t e r r i g e n o u s s e d i m e n t s m a i n l y f r o m t h e B u r d e k i n R i v e r, d r a i n i n g a n a r i d c a t c h m e n t o f a p p r o x i m a t e l y 1 3 0, k m 2 (Cavanagh e t a l ). B o t h, t h e H e r b e r t a n d B u r d e k i n c a t c h m e n t s a r e p r e d o m i n a n t l y r u r a l w i t h o n l y f e w s m a l l u r b a n s e t t l e m e n t s ( < 2 0 0, p o p u l a t i o n ). M a j o r l a n d-u s e i n c l u d e s s u g a r c a n e a g r i c u l t u r a l c r o p s a n d c a t t l e g r a z i n g ( C a v a n a g h e t a l ) SAMPLING B o t h c o r e s w e r e c o l l e c t e d w i t h c u s t o m -m a d e K a s t e n c o r e r s w i t h m m s q u a r e I D s t a i n l e s s s t e e l c o r e t u b e s 2-4 m l o n g. S e d i m e n t c o r e s l i c e s w e r e o b t a i n e d w i t h c l e a n s t a i n l e s s s t e e l t o o l s d u r i n g s h i p b o a r d p r o c e s s i n g. S e d i m e n t c o r e s w e r e s l i c e d a t i n t e r v a l s o f 2 t o 4 c m t o t h e c o r e b o t t o m. S u b s a m p l e s f o r c h e m i c a l a n a l y s e s w e r e t a k e n f r o m t h e s e d i m e n t c o r e s l i c e s a n d f r o z e n. L a r g e r b u l k s a m p l e s w e r e st o r e d s e p a r a t e l y f o r r a d i o c h e m i c a l m e a s u r e m e n t s SEDIMENT CORE CHRONOLOGIES G a m m a s p e c t r o m e t r i c m e a s u r e m e n t s o f P b , R a , C s , a n d o t h e r i s o t o p e s w e r e p e r f o r m e d o n g r a m s o f d r i e d a n d g r o u n d b u l k s e d i m e n t c o r e s l i c e s p a c k e d i n t o a c u s t o m d esigned gas-t i g h t P e r s p e x c o n t a i n e r. A f t e r s t o r a g e f o r 3-4 w e e k s, t h e r a d o n d a u g h t e r i n -g r o w t h a l l o w e d d i r e c t e s t i m a t i o n o f P b f r o m t h e k e V g a m m a e m i s s i o n. R a d i u m w a s e s t i m a t e d f r o m t h e g a m m a p h o t o p e a k s o f P b a t a n d k e V, a n d B i a t k e V. T h e r m o n u c l e a r b o m b f a l l o u t n u c l i d e C s w a s e s t i m a t e d f r o m t h e k e V g a m m a e m i s s i o n o f B a m. F o u r p l a n a r g e r m a n i u m d e t e c t o r s a n d o n e w e l l g e r m a n i u m d e t e c t o r w e r e u s e d f o r t h e s e a n a l y s e s. T h e e n e r g y s p e c t r a o f t h e g a m m a s p e c t r o m e t e r s w e r e c a l i b r a t e d u s i n g A m e r s h a m a n d 4 8
51 C H A P T E R 3 T E M P O R A L D I S T R I B U T I O N C A N M E T s t a n d a r d s o f k n o w n l o w a c t i v i t y s p i k e s o f s u i t a b l e n u c l i d e s i n c l e a n e d s i l i c a s a n d o f g e o m e t r y a n d m a s s s i m i l a r t o t h e s e d i m e n t s a m p l e s. M a r i n e s e d i m e n t r e f e r e n c e m a t e r i a l I A E A w a s u s e d t o c h e c k t h e c a l i b r a t i o n s. I n t e r p r e t a t i o n s o f r a d i o c h e m i c a l t r a c e r s e d i m e n t a t i o n h i s t o r y w e r e b a s e d o n s e v e r a l s u b -m o d e l s d e s c r i b e d b y R o b b i n s ( R o b b i n s ; R o b b i n s ). T h e s e m o d e l s u t i l i s e a s e d i m e n t m i x e d l a y e r t h i c k n e s s, a d e c a d a l -c e n t u r y s c a l e a v e r a g e i n p u t o f e x c e s s P b , B r i s b a n e m e a s u r e m e n t s o f t h e r m o n u c l e a r b o m b f a l l o u t S r -9 0 ( C s ) f r o m (500 Bq m -2 ), a n d d i f f u s i o n c o e f f i c i e n t s f o r P b a n d C s i n m a r i n e s e d i m e n t s ( L i a n d G r e g o r y ). E s t i m a t e s o f t h e a n n u a l a t m o s p h e r i c f l u x o f P b a n d t h e C s i n v e n t o r y h a v e b e e n o b t a i n e d f r o m s o i l p r o f i l e s i n n o r t h Q u e e n s l a n d ( a p p r o x i m a t e l y 5 0 B q 210 Pb m - 2 yr - 1, B q 137 Cs m -2 ) ( B r u n s k i l l e t a l. u n p u b l i s h e d d a t a ). T h e l a r g e s t u n c e r t a i n t y i n e s t i m a t i o n o f t h e a v e r a g e a g e o f a s e d i m e n t c o r e s l i c e i s r e l a t e d t o t h e t h i c k n e s s o f t h e s u r f a c e s e d i m e n t m i x e d l a y e r, w h i c h i s d e f i n e d b y r e l a t i v e l y h o m o g e n e o u s a c t i v i t i e s o f e x c e s s 210 P b a n d Cs PCDD/F ANALYSIS S e d i m e n t s w e r e a n a l y s e d e i t h e r a t Q u e e n s l a n d H e a l t h S c i e n t i f i c S e r v i c e s ( Q H S S ) l a b o r a t o r i e s i n A u s t r a l i a o r a t E r g o F o r s c h u n g s g e s e l l s c h a f t m b H i n G e r m a n y ( E R G O ). A t Q H S S a s c r e e n i n g m e t h o d ( M ü l l e r e t a l a ) w a s u s e d, m o d i f i e d t o a n a l y s e s a m p l e s f o r O C D D c o n c e n t r a t i o n s. A f u l l a n a l y s i s o f a l l 2, 3, 7, 8 -s u b s t i t u t e d a n d Σ h o m o l o g u e P C D D / F s w a s c a r r i e d o u t o n m o s t s a m p l e s a t E R G O u s i n g a c e r t i f i e d m e t h o d (Klärschlammverordn u n g ). B o t h m e t h o d s i n c l u d e d t h e a n a l y s i s o f a n a l y t i c a l b l a n k s a n d q u a n t i f i c a t i o n u s i n g e i t h e r n a t i v e H p C D F i n t e r n a l s t a n d a r d s ( a t Q H S S ) o r 13 C -l a b e l l e d 2, 3, 7, 8 -s u b s t i t u t e d P C D D / F s t a n d a r d s ( a t E R G O ). D e t a i l s o f t h e s e m e t h o d s h a v e b e e n r e p o r t e d i n C h a p t e r QUALITY CONTROL F o r q u a l i t y c o n t r o l t h e r e t e n t i o n t i m e s o f t h e a n a l y t e i n a s a m p l e h a d t o b e w i t h i n 2 s o f t h e r e t e n t i o n t i m e s o f t h e i n t e r n a l s t a n d a r d s. T h e i s o t o p e r a t i o s f o r e a c h c o n g e n e r o f t h e M + a n d M i o n s ( f o r t e t r a c h l o r i n a t e d c o n g e n e r s ) a n d t h e M a n d M i o n s ( f o r p e n t a - t o h e p t a c h l o r i n a t e d c o n g e n e r s ) h a d t o b e w i t h i n 2 0 % o f t h e r e s p e c t i v e i n d i v i d u a l v a l u e. T h e l i m i t o f q u a n t i f i c a t i o n f o r P C D D / F s o r O C D D i n a g i v e n s a m p l e w a s d e f i n e d b y a s i g n a l t o n o i s e r a t i o g r e a t e r t h a n 3 t i m e s t h e a v e r a g e b a s e l i n e v a r i a t i o n a n d 4 9
52 Great Barrier Reef A. Hinchinbrook area Cardwell 1262 Hinchinbrook Herbert River Queensland kilometres B. Burdekin area 1260 Haughton River Ayr Home Hill kilometres Burdekin River kilometres FIGURE 3.1 M A P O F Q UEENSLAND, AU S T R A L I A A N D S I T E S OF S E D I M E N T C O R E S C O L L E C T E D F R O M A. HINCHINBROOK AREA (CORE ) AND B. B URDEKIN AREA (CORE ).
53 C H A P T E R 3 T E M P O R A L D I S T R I B U T I O N a s u b s t a n c e q u a n t i t y i n t h e s a m p l e g r e a t e r t h a n 3 t i m e s t h e q u a n t i t y i n t h e r e s p e c t i v e b l a n k. P r e c a u t i o n s h a v e b e e n t a k e n t o e n s u r e s a m p l e s d i d n o t g e t c o n t a m i n a t e d. S a m p l i n g / s t o r a g e a n d a n a l y t i c a l b l a n k s a s w e l l a s r e p l i c a t e a n a l y s i s w e r e u s e d t o a s s e s s t h e p o s s i b i l i t i e s o f c o n t a m i n a t i o n d u r i n g t h e r e s p e c t i v e s t e p s. A n a l y t i c a l v a r i a b i l i t y w a s t e s t e d b y r e p l i c a t e a n a l y s i s o f s e d i m e n t s f r o m 4 c o r e s e c t i o n s a n d i n s t r u m e n t v a r i a b i l i t y w a s t e s t e d b y r e p l i c a t e i n j e c t i o n o f s e v e r a l s a m p l e s. I n t e r l a b o r a t o r y c o m p a r i s o n s b e t w e e n O C D D c o n c e n t r a t i o n s d e t e r m i n e d a t E R G O a n d Q H S S l a b o r a t o r i e s w e r e c a r r i e d o u t u s i n g r e p l i c a t e a n a l y s i s o f 1 0 c o r e s e c t i o n s o f b o t h H i n c h i n b r o o k a n d B u r d e k i n c o r e s a m p l e s ORGANIC CARBON T o t a l o r g a n i c c a r b o n ( T O C ) w a s d e t e r m i n e d a t t h e Q H S S l a b o r a t o r y a c c o r d i n g t o a s t a n d a r d i s e d p r o c e d u r e ( Q u e e n s l a n d H e a l t h S c i e n t i f i c S e r v i c e s ). I n o r g a n i c c a r b o n a t e s w e r e r e m o v e d u s i n g a c i d c a t a l y s e d d i g e s t i o n ( 1 0 % H C l, 1 % F e C l 2 a t 7 0 o C). T h e r e m a i n i n g m a t e r i a l w a s d r i e d a n d c o m b u s t e d i n t h e L E C O i n d u c t i o n f u r n a c e w i t h s u b s e q u e n t d e t e c t i o n o f C O 2 ( L E C O W R 1 2 C O 2 detector). 3.3 RESULTS PHYSICAL PARAMETERS A r e l a t i v e l y h i g h s e d i m e n t a c c u m u l a t i o n r a t e o f B u r d e k i n c o r e ( g c m - 2 yr - 1 ) r e s u l t e d in e x c e l l e n t t i m e r e s o l u t i o n f o r h i s t o r i c a l r e c o n s t r u c t i o n o f s e d i m e n t a t i o n h i s t o r y. S e d i m e n t f r o m t h e d e e p e s t s l i c e o f t h i s c o r e ( c m ) w a s e s t i m a t e d t o h a v e d e p o s i t e d i n ± 2 0 y e a r s. H i n c h i n b r o o k c o r e h a d a m u c h l o w e r m a s s a c c u m u l a t i o n r a t e ( g c m - 2 yr - 1 ) a n d t h u s r e p r e s e n t s a m u c h l o n g e r p e r i o d o f d e p o s i t i o n a l h i s t o r y. S e d i m e n t f r o m t h e d e e p e s t, c m s l i c e w a s e s t i m a t e d t o h a v e a c c u m u l a t e d a r o u n d ± 5 4 y e a r s. T h e s u r f a c e s e d i m e n t m i x e d l a y e r t h i c k n e s s a t these coring sites average d s e a s o n a l a n d y e a r l y i n p u t s o v e r a p p r o x i m a t e l y 1 8 a n d 3 5 y e a r s, f o r B u r d e k i n c o r e a n d H i n c h i n b r o o k c o r e , r e s p e c t i v e l y. B e l o w t h e 5 1
54 C H A P T E R 3 T E M P O R A L D I S T R I B U T I O N s u r f a c e s e d i m e n t m i x e d l a y e r, t h e s e d i m e n t s w e r e n o l o n g e r m i x e d, a n d t h e s e d i m e n t s l i c e s r e p r e s e n t i n c r e a s i n g a v e ra g e a g e w i t h d e p t h i n t h e c o r e s QUALITY CONTROL V a r i a b i l i t y o f a n a l y t i c a l p r o c e d u r e s, i n c l u d i n g i n t e r l a b o r a t o r y c o m p a r i s o n s a s w e l l a s s p a t i a l a n d t e m p o r a l v a r i a b i l i t y i n m a r i n e s e d i m e n t s w a s t e s t e d e a r l i e r a n d r e p o r t e d i n C h a p t e r 2. T h e c o e f f i c i e n t o f v a r i a n c e ( C V ) i n r e p l i c a t e a n a l y s i s o f s a m p l e s f r o m t h e p r e s e n t s t u d y a v e r a g e d 7. 7 % ( 0. 2 % t o % ) f o r O C D D, w h i c h w a s w i t h i n t h e r a n g e o f i n s t r u m e n t v a r i a b i l i t y f o r s e p a r a t e i n j e c t i o n o f t h e s a m e s a m p l e ( a v e r a g e C V = 7. 5 % ). C V f r o m i n t e r l a b o r a t o r y c a l i b r a t i o n s o f c o r e s e d i m e n t s a n a l y s e d a t E R G O a n d Q H S S a v e r a g e d % ( 1. 3 % t o 4 9 % ) f o r O C D D. R e c o v e r i e s o f i n t e r n a l 13 C -l a b e l l e d s t a n d a r d s a v e r a g e d 7 5 % ( 3 8 % % ) a n d t h e l i m i t o f d e t e c t i o n ( L O D ) a v e r a g e d pg g - 1 ( r a n g e : p g g - 1 ) f o r i n d i v i d u a l P C D D / F c o n g e n e r s TEMPORAL PCDD/F DISTRIBUTION P C D D / F s w e r e q u a n t i f i a b l e i n a l l s e d i m e n t s l i c e s a n a l y s e d. C o n c e n t r a t i o n s o f Σ P C D D / F s, h o m o l o g u e s a n d 2, 3, 7, 8 -s u b s t i t u e d c o n g e n e r s a r e p r e s e n t e d i n T a b l e 3. 1 a n d C o n c e n t r a t i o n s o f Σ P C D D / F s r a n g e d f ro m t o p g g -1 dry weight ( d w ) i n c o r e ( H i n c h i n b r o o k ) a n d t o p g g -1 d w i n c o r e ( B u r d e k i n ) ( F i g u r e 3. 2 ). D u e t o h i g h e r t o t a l o r g a n i c c a r b o n c o n t e n t ( T O C ) i n s e d i m e n t s f r o m t h e H i n c h i n b r o o k c o r e ( c o m p a r e d t o t h e B u r d e k i n c o r e ), P C D D / F c o n c e n t r a t i o n s o n a T O C b a s i s w e r e h i g h e r i n s e d i m e n t s f r o m t h e B u r d e k i n c o m p a r e d t o t h e H i n c h i n b r o o k c o r e ( s e e T a b l e 3. 1 a n d 3. 2 ). I r r e s p e c t i v e o f t h i s, v e r t i c a l t r e n d s o f P C D D / F c o n c e n t r a t i o n w e r e s i m i l a r, e x p r e s s e d e i t h e r o n T O C o r d r y w e i g h t b a s i s. O C D D d o m i n a t e d t h e P C D D / F c o n g e n e r p r o f i l e s i n a l l s a m p l e s a n a l y s e d f o r c o n g e n e r s p e c i f i c P C D D / F p r o f i l e s ( F i g u r e 3. 3 ). O C D D c o n c e n t r a t i o n s r a n g e d f r o m t o p g g - 1 d w i n c o r e ( H i n c h i n b r o o k ) a n d t o p g g - 1 d w i n c o r e ( B u r d e k i n ). ( N o t e t h a t m o r e s a m p l e s h a v e b e e n a n a l y s e d f o r O C D D a t Q H S S, r e s u l t i n g i n t h e h i g h e r c o n c e n t r a t i o n r a n g e o f O C D D c o m p a r e d t o Σ P C D D / F c o n c e n t r a t i o n s a n a l y s e d a t E R G O ). T h e v e r t i c a l d i s t r i b u t i o n o f O C D D a n d Σ P C D D / F c o n c e n t r a t i o n s t h r o u g h o u t t h e d e p t h o f b o t h c o r e s a r e p r e s e n t e d i n F i g u r e T h e s e d a t a s h o w a r e l a t i v e c o n s i s t e n c y o f P C D D / F c o n c e n t r a t i o n o v e r t i m e. 5 2
55 C H A P T E R 3 T E M P O R A L D I S T R I B U T I O N Σ P C D D / F f l u x, b a s e d o n t h e e s t i m a t e d s e d i m e n t f l u x f r o m 210 P b a n d 137 Cs r a d i o c h e m i c a l t r a c e r r e s u l t s, a v e r a g e d 4. 6 g k m - 2 yr -1 i n H i n c h i n br o o k s e d i m e n t s ( C o r e ) r a n g i n g f r o m 2. 6 t o 6. 5 g k m -2 yr - 1. I n B u r d e k i n s e d i m e n t s ( C o r e ), Σ P C D D / F f l u x a v e r a g e d g k m - 2 yr - 1 r a n g i n g f r o m t o g k m -2 yr - 1. B a s e d o n O C D D o n l y, f l u x a v e r a g e d 3. 0 a n d g k m - 2 yr - 1 i n H i n c h i n b r o o k a n d B u r d e k i n c o r e s e d i m e n t s, r e s p e c t i v e l y ,3,7,8-PCDD/F CONGENER PROFILES AND ISOMER PATTERNS 2, 3, 7, 8 -P C D D / F c o n g e n e r p r o f i l e s f r o m c o r e s e d i m e n t s w e r e c o n s i s t e n t l y c h a r a c t e r i s e d b y a ) 2, 3, 7, 8 -P C D F c o n c e n t r a t i o n s n e a r o r b e l o w t h e l i m i t o f d e t e c t i o n ( L O D ), b) 2, 3, 7, 8 -T C D D c o n c e n t r a t i o n s n e a r o r b e l o w t h e L O D, c ) i n c r e a s i n g P C D D c o n c e n t r a t i o n s w i t h i n c r e a s i n g c h l o r i n a t i o n a n d d ) a s t r o n g d o m i n a n c e o f O C D D ( F i g u r e 3. 3 ). 2, 3, 7, 8 -P C D D / F c o n g e n e r p r o f i l e s w e r e s i m i l a r i n c o r e s e d i m e n t s f r o m b o t h t h e H i n c h i n b r o o k a n d B u r d e k i n a n d w e r e r e l a t i v e l y c o n s i s t e n t t h r o u g h o u t t h e d e p t h o f b o t h c o r e s. T h e c o n t r i b u t i o n o f O C D D t o Σ PCDD/Fs averaged 68%, ranging f r o m 4 3 % t o 8 5 % i n a l l c o r e s e d i m e n t s a n a l y s e d f o r 2, 3, 7, 8 -P C D D / F s. Σ P C D D s c o n t r i b u t e d f r o m % t o % t o t h e Σ P C D D / F c o n c e n t r a t i o n. A n o t h e r c h a r a c t e r i s t i c o f t h e c o n g e n e r p r o f i l e s w a s t h e p r e s e n c e o f h i g h e r c o n c e n t r a t i o n s o f 1, 2, 3, 7, 8, 9 -H x C D D c o m p a r e d t o 1, 2, 3, 4, 7, 8 a n d 1, 2, 3, 6, 7, 8 -s u b s t i t u t e d H x C D D s w i t h a n a v e r a g e d i s t r i b u t i o n o f 5 3 %, 1 7 % a n d 3 0 % a m o n g t h e 2, 3, 7, 8 -s u b s t i t u t e d H x C D D s, r e s p e c t i v e l y. T h e i s o m e r p a t t e r n s o f t e t r a - t o o c t a c h l o r i n a t e d h o m o l o g u e s w e r e a l m o s t i d e n t i c a l i n s e d i m e n t s f r o m a l l c o r e d e p t h s i n H i n c h i n b r o o k a n d B u r d e k i n c o r e s. 3.4 DISCUSSION HISTORICAL ANTHROPOGENIC INPUT SIGNIFICANCE T e m p o r a l t r e n d s f r o m t h e p r e s e n t r e s u l t s s h o w r e l a t i v e l y s m a l l c h a n g e s i n P C D D / F c o n c e n t r a t i o n s t h r o u g h o u t t h e d e p o s i t i o n a l p e r i o d s o f b o t h c o r e s ( F i g u r e 3. 2 ). A l t h o u g h P C D D / F c o n c e n t r a t i o n s w e r e i n c r e a s e d i n s e d i m e n t s d e p o s i t e d d u r i n g t h e 2 0 th century, c o m p a r e d t o t h e 1 9 th c e n t u r y, b o t h P C D D / F a n d i n p a r t i c u l a r O C D D l e v e l s a r e c l e a r l y e l e v a t e d t h r o u g h o u t t h e c o r e s e v e n i n s e d i m e n t s a c c u m u l a t e d a s e a r l y a s t h e s. 5 3
56 Estimated year of sedimentation Burdekin core OCDD Sum PCDD/F Concentration pg g -1 dw Estimated year of sedimentation Hinchinbrook core OCDD Sum PCDD/F Concentration pg g -1 dw FIGURE 3.2 V E R T I C A L D I S T R I B U T I O N O F Σ P C D D / F (P G G-1 D W) AND O C D D (P G G -1 D W) C O N C E N T R A T I O N S I N H INCHIN BROOK CORE AND B URDEKIN CORE V E R S U S T H E E S T I M A T E D Y E A R O F S E D I M E N T A T I ON (DERIVED FROM EXCESS PB AND CS PROFILES). ST A N D A R D D E V I A T I O N S IN D I C A T E T H E V A R I A T I O NS FROM REPLICATE AN A L Y S I S
57 TABLE 3.1 C O N C E N T R A T I O N O F P C D D / F HOMOLOGUES AND 2, 3, 7, 8 -S U B S T I T U T ED CONGENERS (I N P G G - 1 D W) I N M A R I N E S E D I M E N T CO R E S F R O M ( H INCHINBROOK) TOTAL ORGANIC CARBON ( % T O C ) IS GIVEN FOR EACH CO RE SLICE ANALYSED. Core depth (cm) Estimated year of deposition 0-2 cm cm cm cm cm cm cm cm 1654 top catch 1641 % TOC n.d Tetra-CDD n.d n.d. n.d. < n.d Σ Tetra-CDD Penta-CDD < Σ Penta-CDD Hexa-CDD Hexa-CDD Hexa-CDD Σ Hexa-CDD Hepta-CDD Σ Hepta-CDD OCDD Tetra-CDF < 0.22 < 0.27 < < 0.25 < 0.46 < 0.33 < 0.45 < 0.37 Σ Tetra-CDF 28 < < 2.6 < Penta-CDF n.d. < n.d. n.d. < n.d. < < < Penta-CDF n.d. < n.d. n.d. n.d. n.d. < < n.d. Σ Penta-CDF n.d. < 1.0 < 0.4 < 0.90 < 0.47 n.d. < < Hexa-CDF n.d. < n.d. n.d. n.d. n.d. < < n.d Hexa-CDF n.d n.d. n.d. < 0.06 n.d. < < n.d Hexa-CDF n.d n.d. n.d. n.d. n.d. n.d n.d Hexa-CDF < 0.39 < 0.15 < 0.29 n.d. < 0.29 n.d. < 0.12 < 0.12 < 0.11 Σ Hexa-CDF < 0.39 < n.d. < 0.62 n.d. < 1.1 < 1.0 < Hepta-CDF n.d. < 0.13 n.d. n.d. < 0.07 n.d. < 0.17 < Hepta-CDF n.d. < n.d. n.d. n.d. n.d. n.d. < n.d. Σ Hepta-CDF n.d n.d. n.d. < 0.07 n.d. < OCDF n.d. < 0.51 n.d. n.d. < 0.31 n.d. < 0.59 < Σ PCDD Σ PCDF Σ PCDD/PCDF n.d. - below limit of detection < - below limit of quantification
58 TABLE 3.2 C O N C E N T R A T I O N O F P C D D / F HOMOLOGUES AND 2, 3, 7, 8 -S U B S T I T U T E D C O N G E N E R S (I N P G G - 1 D W) I N M A R I N E S E D I M E N T CO RE S F R O M ( B URDEKIN ) T OTAL ORGANIC CARBON (% TOC) IS GIVEN FOR EACH CO RE SLICE ANALYSED. Core depth (cm) Estimated year of deposition cm cm cm cm cm cm 1843 top catch 1837 %TOC n.d Tetra-CDD 0.19 < < Σ Tetra-CDD 3.3 < Penta-CDD Σ Penta-CDD Hexa-CDD < Hexa-CDD Hexa-CDD Σ Hexa-CDD Hepta-CDD Σ Hepta-CDD OCDD Tetra-CDF < 0.21 < 0.41 < 0.14 < 0.49 < 0.16 < 0.28 < 0.31 Σ Tetra-CDF 2.3 < < Penta-CDF n.d. < < < n.d. < < Penta-CDF < 0.11 < n.d. < 0.10 n.d. < n.d. Σ Penta-CDF < 0.11 < 1.1 < n.d. < 0.75 < Hexa-CDF n.d. < n.d. n.d. n.d. < < Hexa-CDF n.d. < n.d. n.d. n.d. < Hexa-CDF n.d < < 0.10 n.d Hexa-CDF < 0.14 < 0.16 < 0.21 < 0.27 < 0.24 < 0.17 < 0.20 Σ Hexa-CDF < 0.14 < 1.0 < < 0.24 < 0.90 < Hepta-CDF n.d. < 0.25 n.d. < 0.11 < < Hepta-CDF n.d. n.d. n.d. n.d. n.d. < n.d. Σ Hepta-CDF n.d. < 0.46 n.d. < 0.11 < < OCDF < < 0.68 < 0.40 < 0.22 < Σ PCDD Σ PCDF Σ PCDD/PCDF n.d. - below limit of detection < - below limit of quantification
59 C H A P T E R 3 T E M P O R A L D I S T R I B U T I O N % ΣPCDD/F Tetra-CDD Penta-CDD Hexa-CDD Hexa-CDD Hexa-CDD Hepta-CDD OCDD Tetra-CDF Penta-CDF Penta-CDF Hexa-CDF Hexa-CDF Hexa-CDF Hexa-CDF Hepta-CDF Hepta-CDF OCDF FIGURE 3.3 2, 3, 7, 8 -P C D D / F CONGENER PROFILE IN M A R I N E S E D I M E N T C O R E S FROM Q UEENSLAND, A U S T R A L I A. ST A N D A R D D E V I A T I O N S IN D I C A T E T H E V A R I A T I O N A M O N G A L L S A M P L E S F R O M B O T H C ORES. T y p i c a l l y, h i s t o r i c a l P C D D / F s t u d i e s r e f l e c t t h e o n s e t o f o r g a n o c h l o r i n e u s e w i t h c o n s i d e r a b l e i n c r e a s e s i n P C D D / F c o n c e n t r a t i o n s s t a r t i n g a r o u n d t h e s c o m p a r e d t o p r e i n d u s t r i a l t i m e -p e r i o d s ( B e u r s k e n s e t a l ; H a g e n m a i e r a n d W a l c z o k ; P e a r s o n e t a l ). I n Q u e e n s l a n d s e d i m e n t c o r e s h o w e v e r, P C D D / F c o n c e n t r a t i o n s f r o m a r o u n d t h e s a re c o n s i d e r a b l y h i g h e r t h a n t h o s e r e p o r t e d f r o m P C D D / F i n p u t p e a k s d u r i n g t h e s f r o m o t h e r r u r a l l o c a t i o n s s u c h a s G r e e n L a k e, U S A ( S m i t h e t a l ) o r e v e n t h e r e l a t i v e l y p o l l u t e d B a l t i c P r o p e r ( K j e l l e r a n d R a p p e ). W h i l e P C D D s h a v e b e e n d e t e c t e d e l s e w h e r e i n s e d i m e n t s o r i g i n a t i n g f r o m p r i o r t h e s, c o n c e n t r a t i o n s a r e u s u a l l y f o u n d t o b e re l a t i v e l y l o w a n d h a v e b e e n a t t r i b u t e d t o a t m o s p h e r i c d e p o s i t i o n f r o m e a r l y a n t h r o p o g e n i c P C D D / F e m i s s i o n s o u r c e s (Czuczwa a n d H i t e s ; K j e l l e r e t a l ; J u t t n e r e t a l ). T h e r e l a t i v e l y c o n s i s t e n t a n d elevat e d c o n c e n t r a t i o n s i n Q u e e n s l a n d s e d i m e n t c o r e s o v e r s e v e r a l c e n t u r i e s s u g g e s t s t h e p r e s e n c e o f a P C D D s o u r c e i n p u t i n t o t h e m a r i n e s y s t e m s i n c e a t l e a s t y e a r s. 5 7
60 C H A P T E R 3 T E M P O R A L D I S T R I B U T I O N E u r o p e a n s e t t l e m e n t i n N o r t h Q u e e n s l a n d c o m m e n c e d d u r i n g t h e m i d s, w h i c h l e d t o r a p i d e x p a n d i n g s u g a r c a n e a g r i c u l t u r e t h a t s t i l l r e p r e s e n t s o n e o f t h e m a j o r l a n d -uses w i t h i n t h e l o w e r c a t c h m e n t s o f t h e c o a s t a l f l o o d p l a i n s ( J o h n s o n a n d E b e r t ). E l e v a t e d P C D D / F c o n c e n t r a t i o n s h a v e b e e n d e t e c t e d i n s o i l s u s e d f o r s u g a r c a n e p r o d u c t i o n a n d t h e r o l e o f r e s i d u e s f r o m p e s t i c i d e s u s e d i n t h e s e a r e a s h a s b e e n c o n s i d e r e d w i t h r e s p e c t t o P C D D / F f o r m a t i o n ( C h a p t e r 2 ; M ü l l e r e t a l ). C o m p a r e d t o f o r e x a m p l e i r r i g a t i o n d r a i n s f r o m Q u e e n s l a n d s c o t t o n a g r i c u l t u r a l c r o p s, m o s t o r g a n o c h l o r i n e p e s t i c i de c o n c e n t r a t i o n s a r e c o n s i d e r a b l y l o w e r i n Q u e e n s l a n d s s u g a r c a n e d r a i n s ( M ü l l e r e t a l ), w h e r e a s P C D D / F c o n c e n t r a t i o n s w e r e n e a r o r b e l o w t h e l i m i t o f d e t e c t i o n i n c o t t o n d r a i n s ( C h a p t e r 2 ). I n a d d i t i o n, o r g a n o c h l o r i n e p e s t i c i d e s, a s w e l l a s P C B s, w e r e n o t d e t e c t e d i n s a m p l e s f r o m t h e s a m e s e d i m e n t c o r e s u s e d f o r t h e p r e s e n t s t u d y ( C a v a n a g h e t a l ). I n c o n t r a s t, P C D D / F c o n c e n t r a t i o n s a r e u p t o 6 0 f o l d h i g h e r i n s u g a r c a n e s o i l f r o m Q u e e n s l a n d ( M e a n : p g g - 1 ) ( M ü l l e r e t a l ) c o m p a r e d t o r u r a l a g r i c u l t u r a l s o i l s a m p l e s ( M e a n : p g g - 1 d w ) a n a l y s e d i n G e r m a n y ( R o t a r d e t a l ) o r s u g a r c a n e f a r m s i n B r a z i l a n d S o u t h A f r i c a ( O C D D c o n c e n t r a t i o n 8 p g g - 1 d w a n d 3 3 p g g - 1 d w, r e s p e c t i v e l y ) ( P ä p k e ). Elevated P C D D / F, a n d i n p a r t i c u l a r O C D D c o n c e n t r a t i o n s h a v e a l s o b e e n d e t e c t e d i n Q u e e n s l a n d s o i l s t h a t a r e n o t i n f l u e n c e d b y s u g a r c a n e c u l t i v a t i o n, c o l l e c t e d f r o m N a t i o n a l P a r k s ( C h a p t e r 2 ), p r i s t i n e w e t l a n d a r e a s, b u s h l a n d ( P r a n g e e t a l b ) as w e l l a s i n m a r i n e a n d r i v e r s e d i m e n t s a l o n g t h e e n t i r e c o a s t l i n e ( C h a p t e r 2 ; M ü l l e r e t a l b ). T h i s i s r e m a r k a b l e s i n c e t h e c o n g e n e r p r o f i l e s a n d i s o m e r p a t t er n s o f a l l t h e s e s a m p l e s a r e s i m i l a r, s u g g e s t i n g a s i m i l a r s o u r c e, a n d c o n s i d e r i n g t h a t t h e a r e a o f s a m p l e c o l l e c t i o n e x t e n d s a l o n g t h e e n t i r e k m l o n g c o a s t a l p l a i n a n d i n c l u d e s a v a r i e t y o f a n t h r o p o g e n i c a n d t e r r e s t r i a l i n f l u e n c e s. T h e r o l e o f p o s t -d e p o s i t i o n a l m i x i n g a n d P C D D / F p o r e w a t e r d i f f u s i o n i n s e d i m e n t c o r e s, c a u s e d b y d i a g e n e t i c p r o c e s s e s t h a t m a y a l t e r t h e v e r t i c a l P C D D / F d i s t r i b u t i o n a n d c o n t a m i n a t e d e e p e r c o r e s e c t i o n s h a s b e e n c o n s i d e r e d. T h e m i x i n g o f s e d i m e n t s ( e. g. v i a b i o t u r b a t i o n, w a v e a c t i o n, c u r r e n t s ) a s e s t i m a t e d f r o m r a d i o c h e m i c a l t r a c e r d a t a i s k n o w n a n d r e l a t i v e l y u n i m p o r t a n t i n b o t h c o r e s c o m p a r e d t o t h e i r o v e r a l l s e d i m e n t a c c u m u l a t i o n r a t e s, i n d i c a t i n g t h a t i t i s n o t f e a s i b l e t o a s s u m e t h a t t h e e l e v a t e d P C D D / F l e v e l s i n t h e d e e p e r p a r t s o f t h e c o r e s a r e d u e t o t h e a v e r a g i n g o f y e a r l y P C D D / F i n p u t s d u r i n g m i x i n g p r o c e s s e s. A l t h o u g h l i t t l e e x p e r i m e n t a l d a t a a r e a v a i l a b l e t o q u a n t i f y P C D D / F d i f f u s i o n i n s e d i m e n t p o r e w a t e r, i t i s g e n e r a l l y a s s u m e d 5 8
61 C H A P T E R 3 T E M P O R AL D I S T R I B U T I O N t h a t d u e t o t h e i r p h y s i c o -c h em i c a l p r o p e r t i e s, v e r t i c a l d i f f u s i o n p r o c e s s e s o f s t a b l e h y d r o p h o b i c o r g a n i c c o m p o u n d s s u c h a s P C D D / F s a r e n e g l i g i b l e i n s o i l a n d a q u a t i c s e d i m e n t e n v i r o n m e n t s ( B e u r s k e n s e t a l ). E i s e n r e i c h e t a l c a l c u l a t e d m o l e c u l a r d i f f u s i o n c o e f f i c i e n t s i n l a k e s e d i m e n t s f o r s e v e r a l h i g h m o l e c u l a r w e i g h t c h l or i n a t e d h y d r o c a r b o n s i n c l u d i n g P C B s t o b e i n t h e r a n g e o f cm - 2 s - 1. T h r e e t o 4 m a g n i t u d e h i g h e r d i f f u s i o n c o e f f i c i e n t w o u l d b e r e q u i r e d t o e x p l a i n a c o n t a m i n a t i o n o f t h e d e e p e s t c o r e s l i c e s f r o m t h e s t a r t o f o r g a n o c h l o r i n e u s e d u r i n g t h e e a r l y / m i d s i n s e d i m e n t c o r e s o f t h e p r e s e n t s t u d y. I n a d d i t i o n, s i n c e P C D D / F s a r e m o r e h y d r o p h o b i c t h a n t h e c o m p o u n d s s t u d i e d b y E i s e n r e i c h e t a l , a n e v e n s t r o n g e r s o r p t i o n a n d r e d u c e d m o b i l i t y c a n b e a s s u m e d f o r P C D D / F s. T h e r e f o r e P C D D / F d i f f u s i o n c o e f f i c i e n t s a r e l i k e l y l o w e r, i n p a r t i c u l a r f o r O C D D c o m p a r e d t o P C B s. F u r t h e r, a n e x p o n e n t i a l l y d e c r e a s i n g c o n c e n t r a t i o n g r a d i e n t w o u l d b e e x p e c t e d t o r e s u l t f r o m v e r t i c a l d i f f u s i o n p r o c e s s e s. T h i s w a s n o t o b s e r v e d i n t h e s e d i m e n t c o r e s o f t h e p r e s e n t s t u d y. T h e s m a l l c h a n g e s o f P C D D / F c o n c e n t r a t i o n s t h r o u g h o u t b o t h s e d i m e n t c o r e s f r o m Q u e e n s l a n d a n d r e l a t i v e l y h i g h c o n c e n t r a t i o n s d e t e c t e d i n d e p o s i t e d m a t e r i a l p r i o r t o E u r o p e a n s e t t l e m e n t s u g g e s t t h a t t h e u s e o f x e n o b i o t i c s i s u n l i k e l y t o a c c o u n t f o r t h e r e s u l t s o b s e r v e d. F u r t h e r, t h e s e r e s u l t s i n d i c a t e t h a t a s i g n i f i c a n t s o u r c e o f P C D D / F s, i n p a r t i c u l a r O C D D m a y h a v e b e e n p r e s e n t i n Q u e e n s l a n d b e f o r e i n d u s t r i a l i s a t i o n a n d t h e u s e o f m a n u f a c t u r e d c h l o r i n a t e d o r g a n i c p r o d u c t s NATURAL SOURCES W h i l e t h e m a j o r i t y o f t he g l o b a l P C D D / F b u r d e n t o d a y c a n u n d o u b t e d l y b e a t t r i b u t e d t o a n t h r o p o g e n i c a c t i v i t i e s, e l e v a t e d c o n c e n t r a t i o n s a s w e l l a s c h a r a c t e r i s t i c P C D D s i g n a t u r e s a n d s i m i l a r P C D D c o n c e n t r a t i o n s i n Q u e e n s l a n d s e d i m e n t s d e p o s i t e d a b o u t y e a r s a g o c o m p a r e d t o r e c e n t l y a c c u m u l a t e d m a t e r i a l p r o v i d e i n d i c a t i o n s f o r t h e p r e s e n c e o f a c o n s i s t e n t, n o n -a n t h r o p o g e n i c P C D D s o u r c e i n t h i s e n v i r o n m e n t. T y p i c a l l y, t e m p o r a l P C D D / F r e c o r d s s h o w s t r o n g v e r t i c a l s h i f t s i n P C D D / F c o n g e n e r p r o f i l e s t h a t c o n c u r w i t h t h e o n s e t o f i n d u s t r i a l i s a t i o n a n d r e f l e c t c h a n g e s o f P C D D / F i n p u t s i g n i f i c a n c e t o t h e e n v i r o n m e n t o v e r t i m e ( S m i t h e t a l ; K j e l l e r a n d R a p p e ; H a g e n m a i e r a n d W a l c z o k ; J u t t n e r e t a l ; K j e l l e r ; B r i g h t e t a l ). T h e p r e s e n t r e s u l t s i n d i c a t e t h a t s u c h c h a n g e s a r e n e g l i g i b l e i n s e d i m e n t s f r o m Q u e e n s l a n d a n d t h a t t h e m a j o r c o n t r i b u t i n g s o u r c e m a y h a v e b e e n s i m i l a r o v e r a t l e a s t t h e l a s t 3 c e n t u r i e s. I n a d d i t i o n, t h e c o n g e n e r p r o f i l e s f r o m Q u e e n s l a n d c o r e s e d i m e n t s 5 9
62 C H A P T E R 3 T E M P O R A L D I S T R I B U T I O N a r e h i g h l y c o n s i s t e n t w i t h t h o s e o b s e r v e d i n s u r f a c e m a r i n e a n d e s t u a r i n e s e d i m e n t s a n d s o i l s a l o n g t h e e n t i r e Q u e e n s l a n d c o a s t l i n e ( C h a p t e r 2 ; P r a n g e e t a l b ). I n t e r e s t i n g l y, a n e a s t-w e s t g r a d i e n t h a s b e e n o b s e r v e d w i t h c o n s i d e r a b l y h i g h e r O C D D c o n c e n t r a t i o n s i n t o p s o i l f r o m t h e e a s t e r n c o a s t a l p l a i n s, a n d n o n -d e t e c t a b l e o r v e r y l o w c o n c e n t r a t i o n s b e y o n d t h e G r e a t D i v i d e m o u n t a i n r a n g e s w e s t o f t h e c o a s t l i n e (Prange e t a l b ). T h e s e r e s u l t s p r o v i d e e v i d e n c e f o r t h e p r e s e n c e o f a w i d e s p r e a d a n d u n i f o r m P C D D / F s o u r c e w i t h l o c a l i s e d P C D D i n p u t s i n t o Q u e e n s l a n d s c o a s t a l s y s t e m o v e r a p e r i o d o f a t l e a s t s e v e r a l c e n t u r i e s. I t i s i n t e r e s t i n g t h a t s a m p l e s w i t h s t r i k i n g l y s i m i l a r P C D D / F c o n g e n e r p r o f i l e s h a v e b e e n r e p o r t e d e l s e w h e r e f r o m e i t h e r h i s t o r i c a l s a m p l e s ( H a s h i m o t o e t a l ; H a s h i m o t o e t a l ; R a p p e e t a l b ; G r e e n e t a l ) o r l o c a t i o n s d i s t a n t t o a n t h r o p o g e n i c s o u r c e s ( E m m e r m a n n e t a l ; F e r r a r i o e t a l ; J o b s t a n d A l d a g ; R a p p e e t a l ). C h a r a c t e r i s t i c t o a l l t h e s e s a m p l e s a r e t h e r e l a t i v e l y h i g h O C D D c o n c e n t r a t i o n s, l o w o r n o n-d e t e c t a b l e P C D F c o n c e n t r a t i o n s a n d o f t e n t y p i c a l 2, 3, 7, 8 -H x C D D d i s t r i b u t i o n s, d o m i n a t e d b y t h e 1, 2, 3, 7, 8, 9 / 1, 2, 3, 4, 6, 7 i s o m e r p a i r. T h e s e P C D D / F s i g n a t u r e s c o u l d n o t b e a t t r i b u t e d t o a n y k n o w n p r o f i l e s f r o m a n t h r o p o g e n i c s o u r c e s a n d n a t u r a l f o r m a t i o n p r o c e s s e s w e r e s u g g e s t e d a s p o s s i b l e s o u r c e s f o r t h e c o n t a m i n a t i o n. A n u m b e r o f p r o c e s s e s t h a t o c c u r n a t u r a l l y i n t h e e n v i r o n m e n t h a v e b e e n o b s e r ve d t o r e s u l t i n t h e f o r m a t i o n o f P C D D / F s s u c h a s t h e c o m b u s t i o n o f f o s s i l f u e l s a n d o t h e r n a t u r a l o r g a n i c m a t e r i a l s ( R a p p e e t a l ). S i n c e t h e t r a c e c h e m i s t r i e s o f f i r e t h e o r y f o r e s t f i r e s h a v e b e e n u n d e r i n v e s t i g a t i o n w i t h r e s p e c t t o t h e i r c o n t r i b u t i o n t o t h e e n v i r o n m e n t a l P C D D / F b u r d e n. A l t h o u g h i t h a s b e e n s h o w n t h a t t h e c o m b u s t i o n o f u n c o n t a m i n a t e d w o o d a n d f o r e s t f i r e s c a n l e a d t o t h e f o r m a t i o n o f P C D D / F s ( N e s t r i c k a n d L a m p a r s k i ; T a s h i r o e t a l ; C l e m e n t a n d T a s h i r o ), m o s t s t u d i e s r e m a i n i n c o n c l u s i v e o n t h e s i g n i f i c a n c e o f n a t u r a l f o r e s t f i r e s t o t h e h i s t o r i c a l e n v i r o n m e n t a l P C D D / F b u r d e n d u e t o p r o b l e m s a s s o c i a t e d w it h s a m p l i n g a n d / o r p o s s i b l e c o n t e m p o r a r y c o n t a m i n a t i o n o f f o r e s t s f r o m a n t h r o p o g e n i c P C D D / F e m i s s i o n s. I n t h e a b s e n c e o f q u a n t i t a t i v e m e a s u r e m e n t s o f P C D D / F e m i s s i o n f r o m a c t u a l f i r e s, e m i s s i o n f a c t o r s f r o m c l e a n w o o d b u r n i n g i n o p e n d o m e s t i c f i r e s a r e o f t e n u s e d a s a p r o x y f o r t h e n a t u r a l e v e n t s ( E d u l j e e a n d D y k e ; A l c o c k e t a l ). N a t u r a l f i r e s, A u s t r a l i a n i n d i g e n o u s b u r n i n g p r a c t i c e s a n d f i r e p r a c t i c e s a d o p t e d a f t e r E u r o p e a n s e t t l e m e n t h a v e r e s u l t e d i n e x t e n s i v e a n d f r e q u e n t b u r n i n g o f v e g e t a t i o n a l o n g t h e 6 0
63 C H A P T E R 3 T E M P O R AL D I S T R I B U T I O N c o a s t l i n e o f Q u e e n s l a n d ( A B S ). I n Q u e e n s l a n d, a n e s t i m a t e d 3, k m 2, e q u i va l e n t t o a b o u t 8, 4 0 0, t o n n e s o f n a t i v e f o r e s t, h a v e b e e n c o n s u m e d d u r i n g t h e y e a r d u e t o n a t u r a l e v e n t s ( Q u e e n s l a n d F i r e a n d R e s c u e A u t h o r i t y , p e r s o n a l c o m m u n i c a t i o n ). U s i n g e s t i m a t e s f o r O C D D e m i s s i o n f r o m U K m a s s b a l a n c e s t u d i e s ( A l c o c k e t a l ) a n d a s s u m i n g c o m p l e t e c o m b u s t i o n o f a l l b i o m a s s a s w e l l a s t h e d e p o s i t i o n o f a l l P C D D / F e m i s s i o n s f r o m Q u e e n s l a n d w i t h i n t h e c o a s t a l z o n e, n a t u r a l f o r e s t f i r e s i n Q u e e n s l a n d w o u l d a m o u n t t o a d e p o s i t i o n a l f l u x o f a p p r o x i m a t e l y µg O C D D k m -2 yr -1. S e d i m e n t f l u x c a l c u l a t i o n s f o r O C D D f r o m t h e s e d i m e n t c o r e s i n t h e p r e s e n t s t u d y a r e m o r e t h a n 3 t o 4 o r d e r s o f m a g n i t u d e h i g h e r ( 1-28 g km - 2 yr - 1 ) t h a n t h e s e e s t i m a t e s. F u r t h e r, s t u d i e s t h a t h a v e a n a l y s e d s o i l s o r a s h f r o m p re a n d p o s t b u r n t f o r e s t s r e p o r t e d o n l y r e l a t i v e l y l o w c o n c e n t r a t i o n s a n d s m a l l i n c r e a s e s i n s o i l a f t e r t h e b u r n i n g e v e n t ( T a s h i r o e t a l ; C l e m e n t a n d T a s h i r o ), or c o u l d n o t d e t e c t a n y i m p a c t s o f f o r e s t f i r e s o n s o i l P C D D / F c o n c e n t r a t i o n s ( B u c k l a n d e t a l ; I k o n o m o u e t a l ; M a r t i n e z e t a l ). I n a d d i t i o n, c o m b u s t i o n p r o c e s s e s s u c h a s t h e b u r n i n g o f w o o d t y p i c a l l y r e s u l t i n t h e f o r m a t i o n o f P C D D s a s w e l l a s P C D F s ( W u n d e r l i e t a l ). PCDFs however are n e a r o r b e l o w t h e l i m i t o f d e t e c t i o n i n Q u e e n s l a n d s e d i m e n t s. I t i s i n t e r e s t i n g t h o u g h t h a t c h a n g e s i n 2, 3, 7, 8 -P C D D / F c o n g e n e r p r o f i l e s h a v e b e e n o b s e r v e d i n s o i l a f t e r f o r e s t a n d s t r a w f i r e s w i t h a r e l a t i v e i n c r e a s e o f O C D D ( T a s h i r o e t a l ; W a l s h e t a l ), p o t e n t i a l l y d u e t o a p r o d u c t i o n o f O C D D a n d t h e r m a l d e s t r u c t i o n o r v a p o r i s a t i o n o f l o w e r c h l o r i n a t e d P C D D / F c o n g e n e r s ( W a l s h e t a l ). B a s e d o n t h i s, f o r e s t f i r e s c a n n o t b e e x c l u d e d a s a p o s s i b l e s o u r c e o f P C D D / F s t o Q u e e n s l a n d s e n v i r o n m e n t a t t h i s p o i n t, h o w e v e r, P C D D / F d e p o s i t i o n f r o m t h e s e e v e n t s a n d s u b s e q u e n t t r a n s p o r t t o t h e m a r i n e s y s t e m s e e m u n l i k e l y t o a c c o u n t f o r t h e e l e v a t e d P C D D l e v e l s o b s e r v e d i n t h e m a r i n e s e d i m e n t s o f Q u e e n s l a n d. A l t e r n a t i v e l y, a n u m b e r o f s t u d i e s h a v e d e m o n s t r a t e d t h e f o r m a t i o n o f P C D D / F s f r o m c h l o r i n a t e d p r e c u r s o r s i n v a r i o u s m e d i a s u c h a s s o i l s ( H ö k s t r a e t a l ), s e w a g e s l u d g e ( L a m p a r s k i e t a l ; Ö b e r g e t a l ; K l i m m e t a l ; R a p p e e t a l ), c o m p o s t ( K r a u s s e t a l ; Ö b e r g e t a l ; G r o s s i e t a l ) a n d i n v i t r o e x p e r i m e n t s u s i n g v a r i o u s b i o t i c m e d i a ( W a g n e r e t a l ; F r i e s e t a l ; S i l k e t a l ; W i t t s i e p e e t a l ). C o u p l i n g o f t r i -, tetra - a n d p e n t a c h l o r o p h e n o l s a r e o f t e n s u g g e s t e d m e c h a n i s m s i n v o l v e d i n t h e f o r m a t i o n p r o c e s s, h o w e v e r t h e o n l y n a t u r a l l y o c c u r r i n g c h l o r i n a t e d p h e n o l s i d e n t i f i e d t o d a t e s e e m t o b e r e s t r i c t e d t o d i a n d t r i c h l o r o p h e n o l s ( G r i b b l e ). T h e r e s u l t i n g P C D D / F s i g n a t u r e s f r o m s u c h p r o c e s s e s 6 1
64 C H A P T E R 3 T E M P O R A L D I S T R I B U T I O N h a v e b e e n f o u n d t o b e d e p e n d e n t o n a n u m b e r o f f a c t o r s s u c h a s c o n c e n t r a t i o n s a n d d e g r e e o f c h l o r i n a t i o n o f p r e c u r s o r s u s e d ( W i t t s i e p e e t a l ; H ö k s t r a e t a l ), t y p e o f p e r o x i d a s e s ( W i t t s i e p e e t a l ), a n d o t h e r s u b s t r a t e s p e c i f i c s, i n p a r t i c u l a r o x y g e n c o n t e n t ( K l i m m e t a l ). D u e t o t h e l a r g e n u m b e r o f p o t e n t i a l i n f l u e n c i n g f a c t o r s w i t h i n i n v i v o syst e m s i t i s d i f f i c u l t t o a t t r i b u t e a s p e c i f i c P C D D / F s i g n a t u r e f r o m a n e n v i r o n m e n t t o n a t u r a l l y o c c u r r i n g P C D D / F f o r m a t i o n p r o c e s s e s. N e v e r t h e l e s s, i t i s i n t e r e s t i n g t h a t t h e p r o c e s s e s i n v o l v e d i n s u c h b i o g e n i c f o r m a t i o n p r o c e s s e s s e e m t o r e s u l t m o s t l y i n t h e f o r m a t i o n o f h i g h e r c h l o r i n a t e d P C D D s, i n p a r t i c u l a r O C D D a n d H p C D D s, t h e d o m i n a n t c o n g e n e r s p r e s e n t i n Q u e e n s l a n d s e d i m e n t s a n d s o i l s. O n t h e o t h e r h a n d, i t h a s a l s o b e e n s u g g e s t e d t h a t p o s s i b l e n a t u r a l s o u r c e s o f P C D D / F s m a y r e s u l t f r o m g e o g e n i c fo r m a t i o n p r o c e s s e s s u c h a s v o l c a n i c a c t i v i t y ( G r i b b l e ; T a k i z a w a e t a l ; E m m e r m a n n e t a l ). H o w e v e r, P C D D / F e m i s s i o n d a t a f r o m s u c h e v e n t s a r e f e w a n d i n c o n c l u s i v e ( T a k i z a w a e t a l ; S y m o n s ), i n d ic a t i n g t h e d i f f i c u l t i e s i n v o l v e d i n s a m p l i n g a n d i n t e r p r e t a t i o n w i t h r e s p e c t t o p o s s i b l e c o n t a m i n a t i o n f r o m o t h e r, a n t h r o p o g e n i c s o u r c e s. W i t h r e s p e c t t o t h e P C D D c o n t a m i n a t i o n o b s e r v e d i n Q u e e n s l a n d, t h e h y p o t h e s i s o f b i o g e n i c o r g e o g e n i c f o r m a t i o n o f P C D D / F s i m p l y e i t h e r a c o n t i n u o u s f o r m a t i o n o r h i s t o r i c a l l y o l d s o u r c e ( b u t n e v e r t h e l e s s c o n t i n u o u s i n p u t d u e t o s o i l e r o s i o n p r o c e s s e s ) o f P C D D / F s. S i n c e i t i s e x t r e m e l y d i f f i c u l t t o p i n p o i n t t h e s p e c i f i c p r o c e s s e s a n d t h e i r c o m p l e x i n t e r a c t i o n s t h a t r e s u l t i n t h e c h a r a c t e r i s t i c P C D D / F s i g n a t u r e s o b s e r v e d i n a n e n v i r o n m e n t, a n a s s e s s m e n t o f t h e c o n t i n u i t y o f c o n t a m i n a t i o n m a y p r o v i d e v a l u a b l e i n f o r m a t i o n o n t h e p o s s i b l e p r o c e s s e s i n v o l v e d i n n a t u r a l l y c o n t a m i n a t e d e n v i r o n m e n t s. T h i s m a y b e a c h i e v e d t h r o u g h i n v e s t i g a t i o n s i n t o t h e a l t e r a t i o n s o f t h e s i g n a t u r e s b y p o s t -d e p o s i t i o n a l p r o c e s s e s. 6 2
65 CHAPTER 4 TRANSFORMATION OF PCDD/FS IN ENVIRONMENTAL SINKS Formation of the distinct 1,4-pattern In parts published in: Environmental Science and Technology 2002 (Volume 36, pages ); Organohalogen Compounds 2001(Volume 50, pages ); Organohalogen Compounds 2002(a) (Volume 57, pages )
66 Some material in this chapter was published in the article Caroline Gaus (et al.). Transformation Processes, Pathways, and Possible Sources of Distinctive Polychlorinated Dibenzo-p-dioxin Signatures in Sink Environments, Environmental Science and Technology, vol. 36 (2002), pp Reproduced in part with permission from American Chemical Society. Copyright 2002 American Chemical Society.
67 C H A P T E R 4 TR A N S F O R M A T I O N ABSTRACT I n r e c e n t y e a r s, e n v i r o n m e n t a l s a m p l e s w i t h u n u s u a l d i b e n z o -p -d i o x i n ( P C D D ) c o n g e n e r p r o f i l e s w e r e r e p o r t e d f r o m a r a n g e o f c o u n t r i e s. T h e s e p r o f i l e s, c h a r a c t e r i s e d b y a d o m i n a n c e o f o c t a c h l o r i n a t e d d i b e n z o d i o x i n ( O C D D ) a n d r e l a t i v e l y l o w i n d i b e n z o f u r a n s ( P C D F s ) l e v e l s, c o u l d n o t b e a t t r i b u t e d t o k n o w n s o u r c e s o r f o r m a t i o n p r o c e s s e s. I n t h e p r e s e n t s t u d y, t h e p r o c e s s e s t h a t r e s u l t i n t h e s e u n u s u a l p r o f i l e s w e r e a s s e s s e d u s i n g t h e c o n c e n t r a t i o n s a n d i s o m e r s i g n a t u r e s o f P C D D s f r o m d a t e d e s t u a r i n e s e d i m e n t c o r e s i n Q u e e n s l a n d, A u s t r a l i a. I n d i c a t i o n s f o r t r a n s f o r m a t i o n o f P C D D / F s i g n a t u r e s w e r e a p p a r e n t f r o m t h e i r h is t o r i c a l d i s t r i b u t i o n t h r o u g h t h e s e d i m e n t c o r e s. T h e p r o c e s s e s i n v o l v e d r e s u l t e d i n a s h i f t t o w a r d h i g h e r c o n c e n t r a t i o n s o f t e t r a -t o h e p t a c h l o r i n a t e d h o m o l o g u e s w i t h i n c r e a s i n g a g e a f t e r d e p o s i t i o n. C o r r e s p o n d i n g w i t h t h i s w a s a s i g n i f i c a n t d e c r e a s e i n c o n t r i b u t i o n o f O C D D t o t h e P C D D / F c o n c e n t r a t i o n s w i t h s e d i m e n t a g e. T h e e s t i m a t e d t i m e o f O C D D d i s a p p e a r a n c e ( h a l v i n g i n c o n c e n t r a t i o n s ) w a s t o y e a r s. P r e f e r r e d l a t e r a l, a n a e r o b i c d e c h l o r i n a t i o n o f O C D D r e p r e s e n t s a l i k e l y p a t h w a y f o r t h e s e c h a n g e s. I n Q u e e n s l a n d s e d i m e n t s, t h e s e t r a n s f o r m a t i o n s r e s u l t i n a d i s t i n c t d o m i n a n c e o f i s o m e r s f u l l y c h l o r i n a t e d i n t h e 1, 4, 6, 9 -p o s i t i o n s ( 1, 4 -p a t t e r n s ). A s a r e s u l t o f t h e s e t r a n s f o r m a t i o n s, t h e o r i g i n a l s o u r c e p r o f i l e i n t h e s e e n v i r o n m e n t a l s a m p l e s i s o b s c u r e d, w h i c h m a y h a v e i m p o r t a n t i m p l i c a t i o n s f o r t h e i d e n t i f i c a t i o n o f p o t e n t i a l s o u r c e s f o r t h e s e c o n t a m i n a t i o n s. 6 4
68 C H A P T E R 4 TR A N S F O R M A T I O N 4.1 INTRODUCTION E x t e n s i v e r e s e a r c h o n t h e f o r m a t i o n, f a t e a n d p a t h w a y s o f p o l y c h l o r i n a t e d d i b e n z o -pd i o x i n s ( P C D D s ) a n d d i b e n z o f u r a n s ( P C D F s ) h a s e n a b l e d t h e c o r r e l a t i o n o f h o m o l o g u e a n d c o n g e n e r s i g n a t u r e s f o u n d i n e n v i r o n m e n t a l s a m p l e s t o t h o s e p r o d u c e d b y s p e c i f i c s o u r c e s ( E i t z e r ; H a g e n m a i e r e t a l ; B r u b a k e r a n d H i t e s ; O g u r a e t a l ). H o w e v e r, a l t h o u g h k e y p o l l u t a n t s o u r c e s h a v e b e e n i d e n t i f i e d i n m a n y c o u n t r i e s, l o c a l a n d g l o b a l P C D D / F s o u r c e e m i s s i o n e s t i m a t e s a r e n o t i n b a l a n c e w i t h t h e i r e n v i r o n m e n t a l d e p o s i t i o n. T h i s i m b a l a n c e o c c u r s b o t h i n t e r m s o f c o m p o s i t i o n a n d c o n c e n t r a t i o n, b u t i s e s p e c i a l l y n o t a b l e f o r s i g n i f i c a n t l y h i g h e r l e v e l s o f o c t a c h l o r o d i b e n z o d i o x i n ( O C D D ) i n e n v i r o n m e n t a l s i n k s (Brzuzy and Hites 1996; B r u b a k e r a n d H i t e s ; E i s e n b e r g e t a l ; B a k e r a n d H i t e s ; P r a n g e a n d M ü l l e r ). S u c h m a s s a n d c o m p o s i t i o n i m b a l a n c e s h a v e b e e n a t t r i b u t e d t o ( i ) i n a d e q u a t e l y u n d e r s t o o d t r a n s f o r m a t i o n p r o c e s s e s o f P C D D / F s a l o n g t h e i r t r a n s p o r t p a t h w a y s o r O C D D s y n t h e s i s f r o m p r e c u r s o r s i n t h e e n v i r o n m e n t ( B r u b a k e r a n d H i t e s ; B a k e r a n d H i t e s ), a n d / o r ( i i ) un d e r e s t i m a t e d / y e t u n i d e n t i f i e d c o n t r i b u t i o n s f r o m a n t h r o p o g e n i c o r n a t u r a l P C D D / F s o u r c e s (B r z u z y a n d H i t e s ; G r i b b l e ; P r a n g e a n d M ü l l e r ). C h a p t e r 3 d i s c u s s e d t h e p r e s e n c e o f e l e v a t e d P C D D l e v e l s t h r o u g h o u t a l l s e d i m e n t d e p o s i t i o n l a y e r s, a n d a s e a r l y a s t h e m i d s i n d a t e d s e d i m e n t c o r e s c o l l e c t e d f r o m e s t u a r i n e e m b a y m e n t s i n N o r t h Q u e e n s l a n d. P C D D / F c o n c e n t r a t i o n s w e r e s i m i l a r t h r o u g h o u t t h e s e d i m e n t c o r e s, r a n g i n g f r o m t o p g g - 1 d r y w e i g h t ( d w ) i n H i n c h i n b r o o k C h a n n e l a n d f r o m t o pg g - 1 d w i n B u r d e k i n e s t u a r y c o r e s e d i m e n t s. T h e P C D D / F c o n g e n e r d i s t r i b u t i o n t h r o u g h o u t t h e c o r e s w a s c h a r a c t e r i s t i c a l l y d o m i n a t e d b y O C D D, w h e r e a s P C D F s w e r e g e n e r a l l y n e a r o r b e l o w t h e l i m i t o f q u a n t i f i c a t i o n. T h e s p a t i a l d i s t r i b u t i o n o f s i m i l a r P C D D / F p r o f i l e s i n t o p s o i l a n d s u r f a c e s e d i m e n t s f r o m r u r a l Q u e e n s l a n d w a s f o u n d t o b e e x t e n s i v e, e n c o m p a s s i n g a w i d e v a r i e t y o f e n v i r o n m e n t s a n d t y p e s o f l a n d-u s e w i t h i n ( b u t c o n f i n e d t o ) t h e e n t i r e c o a s t a l r e g i o n ( C h a p t e r 2 ; P r a n g e, e t a l b ). T h e s p a t i a l a n d t e m p o r a l e x t e n t o f s i m i l a r P C D D / F s i g n a t u r e s s u g g e s t e d a l a n d -b a s e d, w i d e s p r e a d, q u a l i t a t i v e l y s i m i l a r a n d h i s t o r i c a l l y o l d P C D D / F i n p u t i n t o t h e Q u e e n s l a n d e n v i r o n m e n t o v e r s e v e r a l c e n t u r i e s. 6 5
69 C H A P T E R 4 TR A N S F O R M A T I O N T o d a t e i t h a s n o t b e e n p o s s i b l e t o i d e n t i f y t h e p r o c e s s e s t h a t r e s u l t i n t h ese c h a r a c t e r i s t i c P C D D / F s i g n a t u r e s a n d e l e v a t e d l e v e l s. L i t t l e i s k n o w n a b o u t t h e n a t u r a l f o r m a t i o n o f P C D D / F s a n d t h e i r s i g n i f i c a n c e i n t h e e n v i r o n m e n t. A d d i t i o n a l l y, t r a n s f o r m a t i o n p r o c e s s e s o f P C D D / F s i n s e d i m e n t a n d s o i l e n v i r o n m e n t s a r e i n a d e q u a t el y u n d e r s t o o d. A f i r s t s t e p t o u n d e r s t a n d i n g t h e p o s s i b l e p r o c e s s e s i n v o l v e d i n t h e f o r m a t i o n o f t h e c h a r a c t e r i s t i c O C D D d o m i n a t e d P C D D s i g n a t u r e s f o u n d i n s o m e e n v i r o n m e n t a l s a m p l e s i s t o d e t e r m i n e w h e t h e r t h e s e r e p r e s e n t t h e a c t u a l s o u r c e o u t p u t p a t t e r n o r a r e t h e r e s u l t o f p o s t-d e p o s i t i o n a l t r a n s f o r m a t i o n p r o c e s s e s o b s c u r i n g t h e o r i g i n a l p a t t e r n s. T o i n v e s t i g a t e t h i s, I h a v e a s s e s s e d p r e v i o u s l y r e p o r t e d s p a t i a l a n d t e m p o r a l P C D D / F d i s t r i b u t i o n s f r o m Q u e e n s l a n d, A u s t r a l i a ( C h a p t e r 2 a n d 3 ), u s i n g a d d i t io n a l n o r m a l i s e d c o n c e n t r a t i o n- a n d i s o m e r-s p e c i f i c a n a l y s i s. 4.2 MATERIALS AND METHODS T h i s p a p e r p r e s e n t s a r e a s s e s s m e n t o f s a m p l e s c o l l e c t e d f o r s t u d i e s o n s p a t i a l a n d t e m p o r a l P C D D / F c o n c e n t r a t i o n s i n t h e c o a s t a l z o n e o f Q u e e n s l a n d w h i c h h a v e b e e n d e s c ri b e d i n C h a p t e r 2 a n d 3. F o r t h e p r e s e n t s t u d y, t h e s e d a t a h a v e b e e n u s e d t o p e r f o r m a d d i t i o n a l, Σ P C D D n o r m a l i s e d h o m o l o g u e c o n c e n t r a t i o n- a n d i s o m e r-s p e c i f i c a n a l y s i s f o r s e d i m e n t, s o i l a n d s e d i m e n t c o r e s a m p l e s ( H i n c h i n b r o o k C h a n n e l a n d B u r d e k i n e s t u a r y d a t e d s e d i m e n t c o r e s ). M a t e r i a l s a n d m e t h o d s f o r s a m p l e c o l l e c t i o n, l o c a t i o n s, P C D D / F a n a l y s i s a n d q u a l i t y c o n t r o l d u r i n g s a m p l i n g, s t o r a g e a n d a n a l y s i s o f s a m p l e s a r e p r e s e n t e d i n C h a p t e r 2 a n d 3. G a m m a s p e c t r o m e t r i c m e a s u r e m e n t s a n d i n t e r p r e t a t i o n s o f t h e s e d i m e n t d e p o s i t i o n a g e o f c o r e s e c t i o n s h a v e b e e n d e s c r i b e d p r e v i o u s l y ( B r u n s k i l l e t a l ). 4.3 RESULTS AND DISCUSSION PCDD/F FINGERPRINTS T h e i s o m e r d i s t r i b u t i o n s o f t e t r a - t o h e p t a c h l o r i n a t e d P C D D s f ro m s e d i m e n t s o f t o p a n d b o t t o m c o r e s e c t i o n s o f H i n c h i n b r o o k C h a n n e l a n d B u r d e k i n e s t u a r y c o r e s a r e p r e s e n t e d i n F i g u r e C h r o m a t o g r a m s f r o m t h e t o p a n d b o t t o m c o r e s l i c e i n t h e H i n c h i n b r o o k c o r e i s s h o w n i n F i g u r e I n g e n e r a l, c o r e s l i c e s f r o m b o t h c o r e s, 6 6
70 C H A P T E R 4 TR A N S F O R M A T I O N r a n g i n g f r o m s e d i m e n t s d e p o s i t e d r e c e n t l y u p t o a p p r o x i m a t e l y y e a r s a g o, s h o w s i m i l a r i s o m e r p a t t e r n s. T h e s e a r e c h a r a c t e r i s e d b y a s t r i k i n g d o m i n a n c e o f i s o m e r s f u l l y c h l o r i n a t e d i n t h e 1, 4, 6, 9 -p o s i t i o n s ( t h e d o m i n a n c e o f 1, 4, 6, 9 -isomers w as c o n f i r m e d b y G C-M S a n a l y s i s u s i n g D B 5 a n d S P c o l u m n s ). T h e a v e r a g e c o n t r i b u t i o n o f t h e s i n g l e 1, 4, 6, 9 -s u b s t i t u t e d i s o m e r s t o t h e i r r e s p e c t i v e h o m o l o g u e g r o u p s i n B u r d e k i n e s t u a r y a n d H i n c h i n b r o o k C h a n n e l c o r e s e d i m e n t s r e s p e c t i v e l y w a s 8 0 % a n d 8 4 % a m o n g b o t h H p C D D s, 7 7 % a n d 8 7 % a m o n g a l l 1 0 H x C D D s ( s u m o f t h r e e 1, 4, 6, 9 -s u b s t i t u t e d i s o m e r s ), 3 4 % a n d 5 3 % a m o n g a l l 1 4 P n C D D s a n d 2 5 % a n d 5 7 % a m o n g a l l 2 2 T C D D s. ( N o t e t h a t t h e c o n c e n t r a t i o n o f 1, 4, 6, 9 -T C D D w a s d e t e r m i n e d b y s u b s t r a c t i o n o f t h e c o -e l u t ed i s o m e r s o n S P f r o m t h o s e c o -e l u t e d o n D B 5 c o l u m n i n j e c t i o n s. ) I n t h e f o l l o w i n g I w i l l r e f e r t o t h i s i s o m e r d i s t r i b u t i o n a s a 1, 4 -p a t t e r n w h i c h, t o m y k n o w l e d g e, i s u n l i k e a n y k n o w n d i r e c t a n t h r o p o g e n i c s o u r c e o u t p u t p a t t e r n a n d h a s n o t b e e n d e sc r i b e d p r e v i o u s l y. M o s t d a t a a v a i l a b l e t o d a t e o n P C D D / F s o u r c e s a n d s i n k s, h o w e v e r, a r e t y p i c a l l y b i a s e d t o w a r d s r e p o r t i n g 2, 3, 7, 8 - s u b s t i t u t e d c o n g e n e r s o n l y, h e n c e s o u r c e s p r o d u c i n g 1, 4 -patterns may simply be u n n o t i c e d. I s o m e r-s p e c i f i c a n a l y s i s a l s o r e v e a l e d a s i m i l a r 1, 4 -p a t t e r n i n m o s t o t h e r s e d i m e n t s a m p l e s a n a l y s e d t o d a t e f r o m Q u e e n s l a n d, i n c l u d i n g t h o s e c o l l e c t e d f r o m r i v e r i n e, e s t u a r i n e a n d m a r i n e l o c a t i o n s a l o n g t h e k m c o a s t l i n e ( F i g u r e 2. 1 s h o w s t h e 1, 4 -p a t t e r n f r o m r i v e r s e d i m e n t s i n t h e H i n c h i n b r o o k a r e a ). A p a r t f r o m t h e s e u n i q u e i s o m e r c h a r a c t e r i s t i c s a l l t h e s e s a m p l e s h a v e i n c o m m o n a s t r o n g d o m i n a n c e o f O C D D a n d l o w o r n o n -d e t e c t a b l e c o n c e n t r a t i o n s o f P C D F s ( C h a p t e r 2 a n d 3 ) TRANSFORMATION OF PCDD/F SIGNATURES I n d i c a t i o n s f o r t r a n s f o r m a t i o n s o f P C D D / F s i g n a t u r e s w e r e a p p a r e n t f r o m h i s t o r i c a l P C D D / F d i s t r i b u t i o n s i n Q u e e n s l a n d s e d i m e n t c o r e s. I n C h a p t e r 3, t h e r e l a t i v e l y c o n s i s t e n t P C D D / F c o n c e n t r a t i o n s i n Q u e e n s l a n d s e d i m e n t c o r e s o v e r t h r e e c e n t u r i e s o f d e p o s i t i o n w e r e d i s c u s s e d. F u r t h e r a n a l y s i s o f t h e s e d a t a r e v e a l s t h a t a l t h o u g h n o s i g n i f i c a n t d i f f e r e n c e s i n Σ P C D D / F c o n c e n t r a t i o n s o v e r t i m e w e r e a p p a r e n t, t h e h i s t o r i c a l d a t a s h o w e d r e l a t i v e l y s m a l l, b u t s i g n i f i c a n t a n d c o n s i s t e n t c h a n g e s o f t h e % c o n t r i b u t i o n o f t e t r a -t o o c t a - h o m o l o g u e g r o u p s t o t h e Σ P C D D c o n c e n t r a t i o n o v e r t h e c o r e s s e d i m e n t a t i o n h i s t o r y ( F i g u r e 4. 3 ). I n b o t h c o r e l o c a t i o n s a n d p a r t i c u l a r l y i n s e d i m e n t s f r o m t h e B u r d e k i n a r e a, t h e c o n t r i b u t i o n o f t e t r a - t o h e p t a c h l o r i n a t e d P C D D s t o t h e Σ P C D D s s i g n i f i c a n t l y i n c r e a s e s w i t h c o r e d e p t h ( r 2 values are given in Figure 4. 3 ). C o r r e s p o n d i n g w i t h t h i s w a s a s i g n i f i c a n t a n d c o n t i n u o u s d e c r e a s e i n c o n t r i b u t i o n 6 7
71 C H A P T E R 4 TR A N S F O R M A T I O N o f O C D D t o t h e Σ P C D D s w i t h s e d i m e n t a g e ( F i g u r e 4. 3 ). S u r f a c e r i v e r s a m p l e s, f o r e s t, a s w e l l a s a g r i c u l t u r a l s o i l c o l l e c t e d i n t h e H i n c h i n b r o o k r e g i o n d u r i n g e a r l i e r s t u d i e s s h o w s i m i l a r P C D D / F c o n c e n t r a t i o n s c o m p a r e d t o t h e H i n c h i n b r o o k C h a n n e l c o r e s e d i m e n t s ( s a m p l e s f r o m C h a p t e r 2 ), h o w e v e r, h i g h e r c o n t r i b u t i o n s o f O C D D a n d l o w e r c o n t r i b u t i o n s o f t e t r a - t o h e p t a c h l o r i n a t e d P C D D c o n g e n e r s a r e a p p a r e n t f r o m t h e s e s a m p l e s ( F i g u r e 4. 3 ). T h i s s u g g e s t s t h a t t h e t r e n d s o f i n c r e a s i n g t e t r a - t o h e p t a c h l o r i n a t e d P C D D s w i t h c o r e d e p t h a r e a f u n c t i o n o f a g e a f t e r d e p o s i t i o n i n t h e m a r i n e s y s t e m d u e t o d e g r a d a t i o n p r o c e s s e s. T h e p r o c e s s e s i n v o l v e d r e s u l t e d i n a s h i f t t o w a r d h i g h e r c o n c e n t r a t i o n s o f t e t r a - t o h e p t a c h l o r i n a t e d h o m o l o g u e s w i t h i n c r e a s i n g a g e a f t e r d e p o s i t i o n a n d s u g g e s t a d e c h l o r i n a t i o n o f h i g h e r c h l o r i n a t e d P C D D s. T h e r e g r e s s i o n s l o p e s o b t a i n e d f r o m F i g u re 4. 3 r e p r e s e n t a p r o x y f o r t h e r e l a t i v e r a t e o f a p p e a r a n c e o f t e t r a -t o h e p t a c h l o r i n a t e d P C D D s a n d t h e r e l a t i v e r a t e o f d i s a p p e a r a n c e o f O C D D w i t h a g e o f d e p o s i t i o n. T h e t i m e o f a p p e a r a n c e ( t w o -f o l d i n c r e a s e i n c o n c e n t r a t i o n ) o f l o w e r c h l o r i n a t e d P C D D s d e c r e a s e d w i t h d e c r e a s i n g d e g r e e o f c h l o r i n a t i o n ( F i g u r e 4. 4 ), w h i c h c o r r e s p o n d s t o r e s u l t s f r o m e x p e r i m e n t a l d e c h l o r i n a t i o n s t u d i e s ( A l b r e c h t e t a l ; F u e t a l ). T h e e s t i m a t e d t i m e f o r O C D D d i s a p p e a r a n c e ( h a l v i n g i n c o n c e n t r a t i o n, c a l c u l a t e d u s i n g t h e r e g r e s s i o n s l o p e s f r o m F i g u r e 4. 3 ) w e r e y e a r s a n d t h e t i m e s o f a p p e a r a n c e o f l o w e r c h l o r i n a t e d P C D D s r a n g e d f r o m y e a r s, l o w e s t f o r Σ T C D D s w i t h years (Figure 4. 4 ). R e p o r t e d h a l f -l i v e s f o r O C D D i n s e d i m e n t o r s o i l e n v i r o n m e n t s v a r y a n d r a n g e f r o m l e s s t h a n 1 0 y e a r s t o m o r e t h a n y e a r s ( M a c k a y e t a l ; K j e l l e r a n d R a p p e ; E i s e n b e r g e t a l ). I n a d d i t i o n, t h e p r o d u c t i o n o f l o w e r c h l o r i n a t e d P C D D s f r o m O C D D a n d H p C D D h a s b e e n o b s e r v e d t o o c c u r w i t h i n d a y s ( S e g s t r o e t a l ; A l b r e c h t e t a l ; F u e t a l ), w h i c h m a y i n d i c a t e t h a t t h e p r o c e s s e s i n t h e Q u e e n s l a n d e n v i r o n m e n t a r e r e l a t i v e l y s l o w. T h e p r e s e n t s t u d y s u g g e s t s t h a t d e c h l o r i n a t i o n p r o c e s s e s h a v e a l t e r e d t h e o r i g i n a l P C D D / F s o u r c e s i g n a t u r e. A f t e r f o r m a t i o n, t h e P C D D s a r e s u b j e c t t o p r o g r e s s i v e d e g r a d a t i o n p r o c e s s e s, p r e d o m i n a n t l y d u r i n g t h e l o n g-t e r m s e d i m e n t a t i o n w i t hi n t h e m a r i n e e n v i r o n m e n t. P C D D s i n s e d i m e n t s f r o m t h e d e e p e s t c o r e s e c t i o n s h a v e b e e n s u b j e c t t o l o n g e r-t e r m d e g r a d a t i o n p r o c e s s e s s i n c e t h e i r d e p o s i t i o n i n t h e m a r i n e s y s t e m c o m p a r e d t o s u r f a c e s e d i m e n t s, i. e. t h e P C D D / F p r o f i l e s i n t h e s u r f a c e s l i c e s o f t h e s e d i m e n t c o r e s, a n d t h o s e f o u n d i n s a m p l e s f r o m r i v e r s e d i m e n t s a n d s o i l, r e p r e s e n t y o u n g s i g n a t u r e s a n d a r e m o r e s i m i l a r t o t h e o r i g i n a l s o u r c e o u t p u t p r o f i l e. 6 8
72 C H A P T E R 4 TR A N S F O R M A T I O N 1,2,4,7 1,2,4,8 1,3,7,8 1,4,6,9 1,2,6,9 1,2,3,6 1,2,3,4* 2,3,7,8* TCDD B 1,2,4,7 1,2,4,8 1,3,7,8 1,4,6,9 1,2,6,9 1,2,3,6 1,2,3,4* 2,3,7,8* TCDD 1,2,4,6,8 1,2,4,7,9 1,2,4,6,9 1,2,4,8,9 1,2,4,6,7 PnCDD 1,2,4,6,8 1,2,4,7,9 1,2,4,6,9 1,2,4,8,9 1,2,4,6,7 PnCDD 1,2,3,7,8* 1,2,3,7,8* 1,2,4,6,7,9 1,2,4,6,8,9 1,2,3,6,7,9 1,2,3,6,8,9 1,2,3,4,6,9 1,2,3,4,7,8* HxCDD 1,2,3,6,7,8* 1,2,3,7,8,9* 1,2,3,4,6,7 1,2,4,6,7,9 1,2,4,6,8,9 1,2,3,6,7,9 1,2,3,6,8,9 1,2,3,4,6,9 1,2,3,4,7,8* HxCDD 1,2,3,6,7,8* 1,2,3,7,8,9* 1,2,3,4,6,7 1,2,3,4,6,7,9* HpCDD 1,2,3,4,7,8,9* HpCDD 1,2,3,4,6,7,8* 1,2,3,4,6,7,8* FIGURE 4.1 IS O M E R P A T T E R N S O F T ET R A- T O H E P T A C H L O R I N A T E D P C D D S (USING A D B -5 C O L U M N) IN A. H INCHINBROOK CORE SEDIM E N T S F R O M T H E SURFACE LAYERS (R E C E N T L Y D E P O S I T E D ) AND B. F R O M T H E B O T T O M LAYER (D E P O S I T E D A P P R O X I M A T ELY YEARS AGO). T HE X -AXIS R E P R E S E N T S T H E % C O N T R I B U T I O N, T H E Y -A X I S R E P R E S E N T S T H E R E L A T I V E R E T E N T I O N T I M E S O F T H E I S O M E R S (O M I T T ED ) DECHLORINATION PATHWAYS D e c h l o r i n a t i o n p a t h w a y s o f O C D D c a n, d u e t o s y m m e t r y c o n s i d e r a t i o n s, p r o c e e d v i a t h e l a t e r a l ( 2, 3, 7, 8 -) a n d / o r p e r i ( 1, 4, 6, 9 -) p o s i t i o n s. T h e 1, 4 -p a t t e r n s i n Q u e e n s l a n d s a m p l e s i n d i c a t e t h e p r e d o m i n a n t l a t e r a l c h l o r i n e e l i m i n a t i o n f r o m O C D D, r e s u l t i n g i n h i g h e r c o n c e n t r a t i o n s o f 1, 2, 3, 4, 6, 7, 9 -H p C D D c o m p a r e d t o 1, 2, 3, 4, 6, 7, 8 -H p C D D ( F i g u r e 4. 2 ). I n s u b s e q u e n t l a t e r a l c h l o r i n e e l i m i n a t i o n s t h e 1, 4, 6, 9 -s u b s t i t u t e d 6 9
73 River sediment Hinchinbrook area Burdekin core sediment 0-2 cm Burdekin core sediment 390 cm Hinchinbrook core sediment 0-2 cm Hinchinbrook core sediment 150 cm % Contribution A / / / / L HxCDD L TCDD L P ncdd LP HxCDD P HxC D D TCDDs PnCDDs HxCDDs HpCDDs / / / / / / / / L Hp C D D P HpCDD FIGURE 4.2 IS O M E R D I S T R I B U T I O N OF T E T R A- T O H E P T A C H L O R I N A T E D P C D D S I N. QU EE N S L A N D S E D I M E N T C O RES, AND RIVER SAMPLES FR O M T H E H INCHINBROOK AREA. WH I T E A R R O W S I N D I C A T E T H E P A T H W A Y O F L A T ERAL DECHLORINATION; BLACK ARROWS INDICAT E T H E ISOMERS RESULTING FRO M L A T E R A L - (L), P E R I -L A T E R A L- (LP) A N D P E R I - (P) DECHLORINATION FROM O C D D. N O T E: 1, 2, 3, 4, 6, 8 - H X C D D W A S C O-E L U T E D I N O SAKA B A Y C O R E S E D I M E N T S W IT H 1, 2, 4, 6, 7, 9 / 1, 2, 4, 6, 8, 9 -H XC D D.
74 C H A P T E R 4 TR A N S F O R M A T I O N 6 5 Estuarine cores Land surface % TCDD y = 0.79e x R 2 = 0.50 y = 0.23e 0.012x R 2 = 0.84 % PnCDD % HxCDD % HpCDD y = 1.7e x R 2 = 0.64 y = 11e x R 2 = 0.65 y = 2.5e 0.010x R 2 = 0.94 y = 16e x R 2 = 0.80 y = 0.42e 0.013x R 2 = 0.93 y = 9.7e x R 2 = 0.78 % OCDD y = 91e x R 2 = y = 71e x 40 R 2 = Estimated year of deposition Hinchinbrook core Burdekin core 0 River sediment Soil FIGURE 4.3 R E L A T I V E I N C R E A S E (C O N T R I B U T I O N O F Σ HOMOLOGUE GROUP - T O Σ P C D D CONCENTRATIONS ) O F T E T R A- T O H E P T A C H L O R I N A T E D P C D DS AND RELATIVE DECREASE OF O C D D W I T H I N C R E A S I N G S E D I M E N T A T ION A G E I N B URDEKIN AND H INCHINBROOK CORE SED I M E N T S A N D W I T H I N THE SHADED AREA - I N T O P S O I L A N D S U R F A CE RIVER SEDIMENTS FR O M T H E H INCHINBROOK AREA. 7 1
75 C H A P T E R 4 TR A N S F O R M A T I O N H x C D D s, P n C D D s a n d T C D D s a r e f o r m e d a s t h e m a i n i s o m e r s i n t h e r e s p e c t i v e h o m o l o g u e gr o u p s w i t h i n c r e a s i n g t i m e o f t r a n s f o r m a t i o n ( F i g u r e 4. 2 ). T h i s r e s u l t s i n a n i n c r e a s e o f 1, 4, 6, 9 -s u b s t i t u t e d i s o m e r c o n t r i b u t i o n s t o t h e r e s p e c t i v e h o m o l o g u e g r o u p s w i t h i n c r e a s i n g a g e a f t e r d e p o s i t i o n o b s e r v e d i n t h e p r e s e n t s t u d y ( F i g u r e 4. 2 i l l u s t r a t e s t h i s f o r t h e t o p a n d b o t t o m s e d i m e n t s l i c e s o f b o t h Q u e e n s l a n d c o r e s ). Years (Burdekin Core) Burdekin Core Hinchinbrook Core Years (Hinchinbrook Core) 0 0 OCDD Total HpCDD Total HxCDD Total PnCDD Total TCDD FIGURE 4.4 E S T I M A T E D T I M E O F D I S A P P E A R A N C E O F O C D D A N D T I M E O F A P P E A R A N C E O F L O W E R CHLORINATED P C D D S USING THE SLOPES O B T A I N E D F R O M T H E R E LATIVE DECREASE OF O C D D A N D R E L A T I V E DECREASE OF LOW E R C H L O R I N A T E D T E T R A - T O H E P T A C H L O R I N A T E D P C D DS WITH INCREASING SE D I M E N T A T I O N A G E I N B URDEKIN AND H INCHINBROOK CORE SED I M E N T S (SEE FIGURE 2), A S S U M I N G T H E F O R M A T I O N O F P C D DS A T T H E T I M E O F S E DI M E N T A T I O N (I. E YEARS UNTIL PRESENT ). A s e x p e c t e d i n a pr e f e r r e d l a t e r a l d e c h l o r i n a t i o n p r o c e s s f r o m O C D D, t h e r a t i o s o f t h e l a t e r a l -d e c h l o r i n a t e d ( L ) t o p e r i -d e c h l o r i n a t e d ( P ) H p C D D s ( 1, 2, 3, 4, 6, 7, 9 - t o 1, 2, 3, 4, 6, 7, 8 -H p C D D ) w e r e f o u n d t o i n f l u e n c e t h e r a t i o s o f L ( 1, 2, 4, 6, 7, 9 - a n d 1, 2, 4, 6, 8, 9 -) to LP (1,2,3,6,7,9 - a n d 1, 2, 3, 6, 8, 9 -) t o P ( 1, 2, 3, 6, 7, 8 - a n d 1, 2, 3, 7, 8, 9 -) H x C D D s, a n d c o n t r i b u t i o n s o f l o w e r c h l o r i n a t e d L i s o m e r s ( 1, 2, 4, 6, 9 -P n C D D a n d 1, 4, 6, 9 -T C D D ) t o t h e r e s p e c t i v e Σ h o m o l o g u e s. F i g u r e 4. 1 a n d 4. 2 p r e s e n t s t h e i s o m e r p a t t e r n s, T a b l e 4. 1 t h e c o r r e s p o n di n g r a t i o s f o r a r a n g e o f 1, 4 -p a t t e r n s a m p l e s w i t h 7 2
76 C H A P T E R 4 TR A N S F O R M A T I O N d i f f e r e n t d e g r e e s o f i n i t i a l d e c h l o r i n a t i o n p r e f e r e n c e ( i. e. r a t i o s o f t h e t w o H p C D D i s o m e r s ). I t i s a p p a r e n t t h a t a m o n g Q u e e n s l a n d s a m p l e s, t h e m o s t d i s t i n c t 1, 4 -p a t t e r n s h o w s t h e h i g h e s t L : P H p C D D r a t i o a n d i s p r e s e n t i n t h e d e e p e s t s e d i m e n t l a y e r ( i. e. l o n g e s t s e d i m e n t a t i o n h i s t o r y ). C o r r e s p o n d i n g l y, t h i s s a m p l e s h o w s t h e h i g h e s t L : L P : P H x C D D r a t i o a n d t h e h i g h e s t % c o n t r i b u t i o n o f L P n C D D a n d L T C D D a m o n g Q u e e n s l a n d s a m p l e s. O n t h e o t h e r h a n d, B u r d e k i n c o r e s e d i m e n t s s h o w l o w e r L : P H p C D D r a t i o s a n d l e s s d i s t i n c t 1, 4 -p a t t e r n s. F u r t h e r, s u r f a c e r i v e r s e d i m e n t s f r o m t h e H i n c h i n b r o o k a r e a, w i t h t h e l e a s t d i s t i n c t 1, 4 -p a t t e r n, s h o w t h e l o w e s t L : P H p C D D r a t i o a n d c o r r e s p o n d i n g l o w e s t L : L P : P H x C D D r a t i o a n d % c o n t r i b u t i o n o f L i s o m e r s. T h e s e t r e n d s i n d i c a t e t h a t t h e f o r m a t i o n o f 1, 4, 6, 9 -i s o m e r s a n d, t h e r e f o r e, t h e o v e r a l l i s o m e r d i s t r i b u t i o n o f t e t r a - t o h e x a-c h l o r i n a t e d P C D D s, i s a l r e a d y d e t e r m i n e d f r o m t h e r a t i o o f t h e t w o H p C D D i s o m e r s ( i. e. t h e a p p e a r a n c e o f 1, 4, 6, 9 -s u b s t i t u t e d i s o m e r s i s g o v e r n e d m a i n l y b y t h e d e c h l o r i n a t i o n p r e f e r e n c e f r o m O C D D a n d r e s u l t i n g P C D D s ) T a b l e 4. 1 c o m p a r e s t h e L : P a n d L : L P : L r a t i o s a n d % c o n t r i b u t i o n s o f L i s o m e r s o f a r a n g e o f s a m p l e s w i t h 1, 4 -p a t t e r n s. R a t i o s o b t a i n e d f ro m o t h e r e s t u a r i n e a n d m a r i n e c o r e o r s u r f a c e s e d i m e n t s ( O s a k a B a y, H a r i m a N a d a, P h i l i p p i n e B a s i n, Y e l l o w S e a, Hong Kong) ( H a s h i m o t o e t a l ; ) s h o w s i m i l a r r a t i o s t o t h o s e f r o m e s t u a r i n e s e d i m e n t s i n Q u e e n s l a n d. T h e b o t t o m s t r a t u m f r o m a M i s s i s s i p p i l a k e ( L a k e M a l l a r d ) ( R a p p e e t a l b ) s h o w s a v e r y d i s t i n c t 1, 4 -p a t t e r n a n d c o r r e l a t e s t o t h e h i g h e s t r a t i o s f r o m t h e e s t u a r i n e c o r e s e d i m e n t s. S a m p l e s c o l l e c t e d f r o m M ississippi rivers (Pascagoula River) ( R a p p e e t a l b ) a n d l a k e s ( L a k e R o g u e H o m a c o r e s ) ( R a p p e e t a l b ) are comparable to ra t i o s o b t a i n e d f o r r i v e r s a m p l e s i n t h e H i n c h i n b r o o k a r e a. I n t e r e s t i n g l y, G e r m a n k a o l i n i t e r a t i o s a r e s i m i l a r t o t h o s e o b t a i n e d f r o m t h e r i v e r s a m p l e s. C o n s i d e r i n g t h e r e s u l t s o f t h i s a n d o t h e r s t u d i e s, t h e d i f f e r e n c e s i n t h e e x t e n t o f 1, 4, 6, 9 -s u b s t i t u t e d i s o m e r d o m i n a n c e a n d t h e r e s u l t i n g d i f f e r e n c e s i n i s o m e r d i s t r i b u t i o n s c a n p r o b a b l y b e e x p l a i n e d b y t h e d e c h l o r i n a t i o n p r e f e r e n c e. L a b o r a t o r y s t u d i e s o n d e c h l o r i n a t i o n o f P C D D / F s d e m o n s t r a t e t h a t t h e s e p r o c e s s e s c a n r a n g e f r o m p r e f e r r e d p e r i - t o p e r i / l a t e r a l a n d p r e f e r r e d l a t e r a l c h l o r i n e e l i m i n a t i o n, d e p e n d i n g o n v a r i o u s p a r a m e t e r s (Hagenmai e r e t a l ; W e b e r e t a l ). T h e h e t e r o g e n e o u s c a t a l y s e d, t h e r m a l d e c h l o r i n a t i o n l e a d s t o a 2, 3, 7, 8 -H x C D D p a t t e r n w i t h a d o m i n a n c e o f 1, 2, 3, 7, 8, 9 -H x C D D (Hagenmaier et al ; W i e s m ü l l e r ), w h i c h i s o n e o f t h e c h a r a c t e r i s t i c s o f t e n r e p o r t e d f o r k a o l i n i t e, b a l l c l a y, M i s s i s s i p p i a n d Q u e e n s l a n d s a m p l e s ( C h a p t e r 2 a n d 3 ; R a p p e e t a l a ; R a p p e e t a l ; F e r r a r i o e t 7 3
77 C H A P T E R 4 TR A N S F O R M A T I O N a l ; R a p p e e t a l ). T h i s c h a r a c t e r i s t i c o f t h e H x C D D i s o m e r p a t t e r n w a s t o d a t e s u p p o r t i n g t h e t h e o r y o f n a t u r a l P C D D f o r m a t i o n i n t h e s e s a m p l e s s i n c e i t c o u l d n o t b e a t t r i b u t e d t o a k n o w n a n t h r o p o g e n i c s o u r c e o u t p u t. H o w e v e r, t h e d a t a p r e s e n t e d h e r e s t r o n g l y s u g g e s t s t h a t d e c h l o r i n a t i o n p r o c e s s e s a r e a t p r e s e n t t h e o n l y f o r m a t i o n m e c h a n i s m s t h a t c a n e x p l a i n t h e s p e c i f i c d i s t r i b u t i o n o f 2, 3, 7, 8 -s u b s t i t u t e d H x C D D s. TABLE 4.1 R A T I O S O F L A T E R A L D E C H L O R I N A T E D (L) AND PERI DECHLORINAT ED (P) H P C D D S (I. E. 1, 2, 3, 4, 6, 7, 9 -H P C D D : 1, 2, 3, 4, 6, 7, 8 -H P C D D ) AND L : LP : P HX C D DS (I.E. 1, 2, 4, 6, 7, 9 / 1, 2, 4, 6, 8, 9 -H X C D D : 1, 2, 3, 6, 7, 9 -/ 1, 2, 3, 6, 8, 9 - H X C D D : 1, 2, 3, 6, 7, 8 -/ 1, 2, 3, 7, 8, 9 -/ 1, 2, 3, 4, 6, 7 -H X C D D ) AND % C O N T R I B U T I O N O F L PN C D D (I. E. 1, 2, 4, 6, 9 -PNC D D ) AND L TCDD (I. E. 1, 4, 6, 9 -T C D D ) T O T H E Σ H O M O L O G U E G R O U P I N A R A N G E O F S A M P L E S F R O M Q UEENSLAND AND ELSEWHERE. L : P HpCDD L : LP : P HxCDD % L PnCDD Marine and estuarine sediments Hinchinbrook (150 cm) a 8 : : 5 : Hinchinbrook (0-2 cm) a 4 : 1 53 : 7 : Burdekin (390 cm) a 5 : 1 22 : 4 : Burdekin (0-2 cm) a 4 : 1 11 : 2 : Hong Kong (33-40) cm a 5 : 1 23 : 6 : Yellow Sea (surface) b 4 : 1 nd nd nd Osaka Bay (200 cm) c ~3 : 1 ~10 : 3 : 1 nd nd Philippine Basin ( cm) b 3 : 1 nd nd nd Lake and river sediments Mississippi Lake (bottom) d na ~34 : 2 : 1 na na River, Hinchinbrook area a 2 : 1 4 : 1 : Mississippi River (Pascagoula) e ~2 : 1 ~4 : 2 : 1 ~33 na Mississippi Lake (Rogue Homa) d na ~4 : 2 : 1 na na Kaolinite clay German kaolinite clay a 2 : 1 5 : 2 : a Present study b Calculated from PCDD concentrations published in (Hashimoto, Wakimoto 1995) c Calculated from isomer distribution published in (Hashimoto, Wakimoto 1990) d Calculated from isomer distribution published in (Rappe et al. 1997b) e Calculated from isomer distribution published in (Rappe et al. 1997a) na not available nd not detected % L TCDD 7 4
78 C H A P T E R 4 TR A N S F O R M A T I O N A p r e f e r r e d la t e r a l d e c h l o r i n a t i o n w a s r e c e n t l y r e p o r t e d b y O h t s u k a e t a l. f r o m s t u d i e s o n p h o t o d e g r a d a t i o n p a t h w a y s u s i n g U V ( n m ) r a d i a t i o n ( O h t s u k a e t a l ). R e m a rk a b l y, t h e C l H p h o t o c h e m i c a l s u b s t i t u t i o n p a t h w a y s r e s u l t e d i n a 1, 4, 6, 9 - d o m i n a t e d i s o m e r p a t t e r n, s t r i k i n g l y s i m i l a r c o m p a r e d t o t h e Q u e e n s l a n d s a m p l e s. T h e r e f o r e, p a t t e r n s w i t h L : L P : P H x C D D r a t i o s a s t h e y a r e f o u n d i n t h e 1, 4 -p a t t e r n s a r e l i k e l y t o re s u l t f r o m d e c h l o r i n a t i o n p r o c e s s e s. W i t h r e s p e c t t o Q u e e n s l a n d s a n d o t h e r d e e p c o r e s e d i m e n t s, h o w e v e r, U V r a d i a t i o n i s u n l i k e l y t h e c a t a l y s t o f t h e o b s e r v e d t r a n s f o r m a t i o n o f P C D D s i g n a t u r e s. S i n c e t h e s e d i m e n t s a n a l y s e d d u r i n g t h e p r e s e n t s t u d y a r e p re d o m i n a n t l y a n a e r o b i c t o s e m i -a n a e r o b i c, r e d u c t i v e d e c h l o r i n a t i o n s e e m s a m o r e l i k e l y m e c h a n i s m f o r t h e t r a n s f o r m a t i o n p r o c e s s e s w i t h r e s p e c t t o t h e s e d i m e n t e n v i r o n m e n t o f Q u e e n s l a n d. D e c h l o r i n a t i o n o f P C D D s ( b y m i c r o b i a l a n d / o r a b i o t i c p r o c e s s e s ) h a s b e e n d e m o n s t r a t e d d u r i n g a n u m b e r o f s t u d i e s u n d e r t h e r e d u c i n g c o n d i t i o n s p r e v a i l i n g i n s e d i m e n t s ( A d r i a e n s e t a l ; B e u r s k e n s e t a l ; A l b r e c h t e t a l ; F u e t a l ; B u n g e e t a l ). S e v e r a l p a t h w a y s h a v e b e e n i d e n t i f i e d d e p e n d i n g o n m i c r o o r g a n i s m s p r e s e n t, t h e s u b s t i t u t i o n p a t t e r n s o f t h e o r i g i n a l s o u r c e p r o f i l e a n d a n u m b e r o f a b i o t i c f a c t o r s. A b i o t i c a n d b i o t i c d e c h l o r i n a t i o n w a s o b s e r v e d a t r o o m t e m p e r a t u r e i n h i s t o r i c a l l y P C D D / F c o n t a m i n a t e d e s t u a r i n e s e d i m e n t s ( A l b r e c h t e t a l ). T h e s e p r o c e s s e s h o w e v e r, r e s u l t e d m a i n l y i n t h e r e m o v a l o f a p e r i -c h l o r i n e ( r a t i o o f L : P H p C D D 1 : 4 ). A d i c h o t o m o u s m i c r o b i a l d e c h l o r i n a t i o n p a t h w a y f o r h i g h l y c h l o r i n a t e d P C D D s w a s r e p o r t e d f r o m P a s s a i c R i v e r s e d i m e n t s ( B a r k o v s k i i a n d A d r i a e n s a ; b ), i n c l u d i n g a m i x e d p e r i -l a t e r a l d e c h l o r i n a t i o n f o r n o n -2, 3, 7, 8 - s u b s t i t u t e d c o n g e n e r s. S i m i l a r t o t h e 1, 4 -p a t t e r n s o f t h e p r e s e n t s t u d y, a n i n c r e a s e i n 1, 2, 3, 7, 8, 9 -H x C D D w a s r e p o r t e d i n a n a e r o b i c s e d i m e n t c o r e s f r o m L a k e K e t e l m e e r ( B e u r s k e n s e t a l ). A s u b s e q u e n t s t u d y f r o m L a k e K e t e l m e e r i n d i c a t e d t h a t s p e c i f i c m i c r o o r g a n i s m s a r e c a p a b l e o f s i m u l t a n e o u s l a t e r a l - a n d p e r i -d e c h l o r i n a t i o n a c t i v i t i e s ( B e u r s k e n s e t a l ). R e c e n t l y, b a c t e r i a f r o m S p i t t e l W a s s e r s e d i m e n t w e r e f o u n d t o s e l e c t i v e l y d e c h l o r i n a t e t h e l a t e r a l p o s i t i o n s ( " S P-p a t h w a y " ) (Bunge et al ). T h e r e s u l t s i n d i c a t e t h a t a s p e c i f i c l a t e r a l d e c h l o r i n a t i o n b y m i c r o o r g a n i s m s i s p o s s i b l e a n d m a y t h e r e f o r e p r o v i d e a p o t e n t i a l m e c h a n i s m f o r t h e t r a n s f o r m a t i o n o f P C D D s o u r c e p r o f i l e s i n t o t h e 1, 4, 6, 9 -d o m i n a t e d s ig n a t u r e s o b s e r v e d. H o w e v e r, o n l y t h e 1, 2, 3, 4 -tetra -C D D t o 1, 2, 4 -tri -C D D p a t h w a y w a s i n v e s t i g a t e d i n t h i s s t u d y, w i t h 1, 2, 3, 4 -T C D D e x h i b i t i n g d i f f e r e n t c h a r g e d i s t r i b u t i o n s c o m p a r e d t o h i g h e r c h l o r i n a t e d P C D D s. B u n g e e t a l. ( B u n g e e t a l ) c o n c l u d e d t h a t t h e p o s i t i o n a n d c o n g e n e r 7 5
79 C H A P T E R 4 TR A N S F O R M A T I O N s p e c i f i c i t y o f m i c r o b i a l P C D D r e d u c t i v e d e c h l o r i n a t i o n m i g h t d e p e n d o n s p e c i f i c b a c t e r i a. D i f f e r e n c e s i n L : P a n d L : L P : P i s o m e r r a t i o s o b s e r v e d i n t h e 1, 4 -p a t t e r n s o f e s t u a r i n e / m a r i n e a n d r i v e r / l a k e s a m p l e s m a y t h e r e f o r e d e p e n d, i n a d d i t i o n t o t i m e f r a m e s a v a i l a b l e f o r t r a n s f o r m a t i o n, o n t h e b i o t i c e n v i r o n m e n t o f t h e s p e c i f i c l o c a t i o n s. T h e 1, 4 -p a t t e r n s w i t h l o w e r r a t i o s o b s e r v ed in lake and river sediments (L:P H p C D D r a t i o o f a b o u t 2 : 1 ) c o u l d e v e n b e e x p e c t e d f r o m t h e r e s u l t s o f B u e r s k e n s e t a l. ( B e u r s k e n s e t a l ) w i t h a h i g h i m p a c t o f p e r i -d e c h l o r i n a t i o n. I n a d d i t i o n, t h e p r e s e n c e o f p h e n o l s a n d h u m i c c o n s t i t u e n t s h a s b e e n s u g g e s t e d t o i n f l u e n c e t h e p r e f e r r e d p a t h w a y s o f d e c h l o r i n a t i o n r e a c t i o n s ( B a r k o v s k i i a n d A d r i a e n s ; F u e t a l ). T h e p r e s e n t r e s u l t s d e m o n s t r a t e t h a t P C D D / F t r a n s f o r m a t i o n p r o c e s s e s h a v e o c c u r r e d i n t h e m a r i n e a n d e s t u a r i n e e n v i r o n m e n t o f Q u e e n s l a n d, A u s t r a l i a. T h e s e p r o c e s s e s r e s u l t i n a s h i f t t o w a r d s l o w e r c h l o r i n a t e d c o n g e n e r s v i a f o r m a t i o n o f 1, 4, 6, 9 -s u b s t i t u t e d c o n g e n e r s w i t h t i m e a f t e r d e p o s i t i o n. R e d u c t i v e d e c h l o r i n a t i o n p r e s e n t s a l i k e l y p a t h w a y s f o r t h e s e t r a n s f o r m a t i o n s. A s a c o n s e q u e n c e, t h e e n v i r o n m e n t a l s a m p l e s d o n o t r e f l e c t t h e o r i g i n a l s o u r c e p r o f i l e. T h i s m a y h a v e i m p l i c a t i o n s o n t h e i d e n t i f i c a t i o n o f p o t e n t i a l s o u r c e s i n a r e a s w h e r e 1, 4 -p a t t e r n s h a v e b e e n o b s e r v e d, w h i c h a r e d i s c u s s e d i n t h e f o l l o w i n g c h a p t e r. 7 6
80 CHAPTER 5 AN ALTERNATIVE HYPOTHESIS TO NATURAL PCDD FORMATION Indications for anthropogenic formation In parts published in: Environmental Science and Technology 2002 (Volume 36, pages ); Organohalogen Compounds 2002 (b) (Volume 59, pages )
81 Some material in this chapter was published in the article Caroline Gaus (et al.). Transformation Processes, Pathways, and Possible Sources of Distinctive Polychlorinated Dibenzo-p-dioxin Signatures in Sink Environments, Environmental Science & Technology vol. 36 (2002), pp Reproduced in part with permission from American Chemical Society. Copyright 2002 American Chemical Society.
82 C H A P T E R 5 A L T E R N A T I V E H Y P O T H E S I S ABSTRACT E n v i r o n m e n t a l s a m p l e s f r o m A u s t r a l i a, U. S. A., G e r m a n y, J a p a n, C h i n a, P h i l i p p i n e s a n d H o n g K o n g h a v e b e e n r e p o r t e d w i t h s i m i l a r, b u t u n u s u a l c o n g e n e r p r o f i l e s o f p o l y c h l o r i n a t e d d i b e n z o -p -d i o x i n s a n d d i b e n z o f u r a n s ( P C D D / F s ). T h e s e c o n g e n e r c h a r a c t e r i s t i c s c o u l d n o t b e a t t r i b u t e d t o a n y k n o w n a n t h r o p o g e n i c s o u r c e a n d t h e p o t e n t i a l f o r m a t i o n p r o c e s s w a s s u g g e s t e d t o b e o f n a t u r a l o r i g i n. T h e p r e s e n t s t u d y i n v e s t i g a t e d t h e a v a i l a b l e P C D D / F d a t a i n t h e l i t e r a t u r e f r o m t h e s e n a t u r a l f o r m a t i o n s a m p l e s, c o m p a r i n g t h e m t o s o i l a n d s e d i m e n t s c o l l e c t e d f r o m Q u e e n s l a n d, A u s t r a l i a. T h e r e s u l t s re v e a l e d t h a t n o t o n l y d o t h e c o n g e n e r p r o f i l e s a n d l a t e r a l l y s u b s t i t u t e d H x C D D s s h o w c l e a r s i m i l a r i t i e s, b u t t h e d i s t r i b u t i o n o f a l l i n d i v i d u a l P C D D i s o m e r s a r e s i m i l a r i n m o s t s a m p l e s. T h e s e a r e c h a r a c t e r i s e d b y a s t r i k i n g d o m i n a n c e o f i s o m e r s c h l o r i n a t ed i n t h e 1, 4, 6, 9 -p o s i t i o n s. T h i s d i s t i n c t f i n g e r p r i n t, r e f e r r e d t o a s 1, 4 - p a t t e r n, h a s b e e n s h o w n t o r e s u l t f r o m t r a n s f o r m a t i o n p r o c e s s e s i n t h e e n v i r o n m e n t. C o n s e q u e n t l y, t h e e n v i r o n m e n t a l s a m p l e s d o n o t r e f l e c t t h e s i g n a t u r e s o f t h e o r i g i n a l s o u r c e, a n d a n y f o r m a t i o n p r o c e s s t h a t r e s u l t s i n t h e p r e d o m i n a n t p r o d u c t i o n o f O C D D r e p r e s e n t s a p o s s i b l e s o u r c e i n p u t. P o t e n t i a l a l t e r n a t i v e s o u r c e s t o n a t u r a l f o r m a t i o n w e r e i d e n t i f i e d b y c o m p a r i n g t h e 1, 4 -p a t t e r n s t o i s o m e r d i s t r i b u t i o n s c a u s e d b y k n o w n c o n t a m i n a t i o n s o u r c e s. A n a l t e r n a t i v e h y p o t h e s i s e s i s d e v e l o p e d, w h e r e b y a n a n t h r o p o g e n i c P C D D p r e c u r s o r i n p u t ( e. g. p e n t a c h l o r o p h e n o l ) r e s u l t s i n t h e c o n t a m i n a t i o n. C o n v e r s i o n o f P C P t o O C D D a n d s u b s e q u e n t t r a n s f o r m a t i o n t o 1, 4 - p a t t e r n s m a y r e p r e s e n t a p o t e n t i a l f o r m a t i o n p r o c e s s. T h e s e r e s u l t s a n d h y p o t h e s i s i m p l y f u r t h e r i n v e s t i g a t i o n s a r e w a r r a n t e d i n t o p o s s i b l e a n t h r o p o g e n i c s o u r c e s i n a r e a s w h e r e n a t u r a l P C D D f o r m a t i o n h a s b e e n s u g g e s t e d. 7 8
83 C H A P T E R 5 A L T E R N A T I V E H Y P O T H E S I S 5.1 INTRODUCTION I n r e c e n t y e a r s, a n u m b e r o f e n v i r o n m e n t a l ( s e d i m e n t / s o i l ) s a m p l e s f r o m p r e d e p o s i t s a n d r u r a l a r e a s h a v e b e e n r e p o r t e d w i t h u n u s u a l c o n g e n e r p r o f i l e s o f p o l y c h l o r i n a t e d d i b e n z o -p -d i o x i n s ( P C D D s ) a n d p o l y c h l o r i n a t e d d i b e n z o f u r a n s ( P C D F s ). T h e s e s a m p l e s w e r e c h a r a c t e r i s e d b y e l e v a t e d l e v e l s o f P C D D s d o m i n a t e d b y t h e o c t a c h l o r i n a t e d d i b e n z o d i o x i n ( O C D D ), t h e d o m i n a n c e o f t h e 1, 2, 3, 7, 8, 9 - s u b s t i t u t e d h e x a c h l o r i n a t e d d i b e n z o d i o x i n ( H x C D D ) a m o n g t h e t h r e e l a t e r a l l y s u b s t i t u t e d H x C D D s, a n d a g e n e r a l l a c k, o r r e l a t i v e l y l o w c o n c e n t r a t i o n s, o f P C D F s. S u c h c h ar a c t e r i s t i c s i g n a t u r e s h a v e b e e n f o u n d m o s t l y i n s e d i m e n t s, b u t a l s o i n s o i l / c l a y s a m p l e s c o l l e c t e d f r o m A u s t r a l i a ( C h a p t e r 2 a n d 3 ; P r a n g e e t a l b ) U. S. A. ( F e r r a r i o e t a l ; R a p p e a n d A n d e r s s o n ), G e r m a n y ( R a p p e a n d A n d e r s s o n ), J a p a n ( H as h i m o t o e t a l ; ), C h i n a ( H a s h i m o t o e t a l ), P h i l i p p i n e s ( H a s h i m o t o e t a l ) a n d H o n g K o n g ( M ü l l e r e t a l ). A l l t h e s e s t u d i e s c o n c l u d e d t h a t ( i ) t h e c h a r a c t e r i s t i c a n d u n u s u a l P C D D / F p r o f i l e s c o u l d n o t b e a t t r i b u t e d t o k n o w n a n t h r o po g e n i c s o u r c e i n p u t s a n d / o r ( i i ) P C D D s h a v e b e e n p r e s e n t i n s e d i m e n t s d e p o s i t e d p r i o r t o t h e p r o d u c t i o n o f o r g a n o c h l o r i n e s, i n d i c a t i n g t h a t t h e s p e c i f i c P C D D f o r m a t i o n p r o c e s s m a y b e o f n o n-a n t h r o p o g e n i c n a t u r e. I n v e s t i g a t i o n s i n Q u e e n s l a n d, h o w e v e r, s t r o n g l y s u g g e s t t h a t i t i s n o t t h e P C D D / F s s o u r c e i t s e l f, b u t p o s t -t r a n s f o r m a t i o n d e c h l o r i n a t i o n p r o c e s s e s i n t h e e n v i r o n m e n t w h i c h r e s u l t i n t h e o b s e r v e d P C D D / F p r o f i l e s ( C h a p t e r 4 ). P r e f e r r e d l a t e r a l, a n a e r o b i c d e c h l o r i n a t i o n o f O C D D r e p r e s e n t s a l i k e l y p a t h w a y r e s u l t i n g i n t h e t y p i c a l s i g n a t u r e s o b s e r v e d. T h e d i s t i n c t s i g n a t u r e s r e s u l t i n g f r o m t h e s e t r a n s f o r m a t i o n s a r e c h a r a c t e r i z e d b y t h e d o m i n a n c e o f i s o m e r s c h l o r i n a t e d i n t h e 1, 4, 6, 9 -p o s t i t i o n s ( r e f e r r e d t o a s 1, 4 - p a t t e r n ). T h e s e d i s t i n c t p a t t e r n s i n c l u d e t h e s p e c i f i c d i s t r i b u t i o n o f 2, 3, 7, 8 -s u b s t i t u t e d H x C D D ( d o m i n a n c e o f t h e 1, 2, 3, 7, 8, 9 -s u b s t i t u t e d h e x a c h l o r i n a t e d d i b e n z o d i o x i n ( H x C D D ) a m o n g t h e t h r e e l a t e r a l l y s u b s t i t u t e d H x C D D s ), w h i c h w a s i d e n t i f i e d i n o t h e r n a t u r a l f o r m a t i o n s a m p l e s. T h i s m a y i n d i c a t e t h a t s u c h t r a n s f o r m a t i o n p r o c e s s e s a r e n o t r e s t r i c t e d t o t h e e n v i r o n m e n t o f Q u e e n s l a n d. A s a r e s u l t o f t h e s e e n v i r o n m e n t a l t r a n s f o r m a t i o n s, t h e P C D D / F p r o f i l e s i n Q u e e n s l a n d d o n o t r e f l e c t t h e s i g n a t u r e s o f t h e o r i g i n a l s o u r c e, a n d a n y f o r m a t i o n p r o c e s s t h a t r e s u l t s i n t h e p r o d u c t i o n o f p r e d o m i n a n t l y O C D D r e p r e s e n t s a p o s s i b l e s o u r c e i n p u t. I t i s t h e r e f o r e f e a s i b l e t o c o n s i d e r a n t h r o p o g e n i c p r e c u r s o r s t h a t a r e c a p a b l e o f f o r m i n g 7 9
84 C H A P T E R 5 A L T E R N A T I V E H Y P O T H E S I S O C D D. I n t h e p r e s e n t s t u d y, I c o m p i l e d a n d c o m p a r e d p u b l i s h e d d a t a o n n a t u r a l f o r m a t i o n s a m p l e s a n d p r o v i d e a r g u m e n t s t o s u p p o r t a h y p o t h e s i s t h a t P C D D / F p r e c u r s o r s m a y c o n t r i b u t e t o t h e d e v e l o p m e n t o f t h e d i s t i n c t 1, 4 -p a t t e r n o f P C D D / F c o n t a m i n a t i o n i n e n v i r o n m e n t a l s a m p l e s w o r l d w i d e. 5.2 RESULTS AND DISCUSSION GLOBAL 1.4-PATTERNS D i s t i n c t 1, 4 -p a t t e r n s ( d o m i n a n c e o f i s o m e r s s u b s t i t u t e d i n t h e 1, 4, 6, 9 -p o s i t i o n s ) i n Q u e e n s l a n d s e n v i r o n m e n t h a v e b e e n i d e n t i f i e d a n d d i s c u s s e d i n C h a p t e r 4. C o m p a r i n g t h e Q u e e n s l a n d P C D D / F f i n g e r p r i n t s t o i s o m e r p a t t e r n s o r c o n c e n t r a t i o ns p u b l i s h e d f r o m o t h e r n a t u r a l f o r m a t i o n s a m p l e s, s t r i k i n g s i m i l a r i t i e s b e c o m e a p p a r e n t. F i g u r e 5. 1 s h o w s t h e i s o m e r d i s t r i b u t i o n s o f a r a n g e o f s a m p l e s r e p o r t e d i n t h e l i t e r a t u r e w h e r e a n a t u r a l f o r m a t i o n o f P C D D s w a s s u g g e s t e d. I s o m e r s f r o m s e d i m e n t s i n a J a p a n e s t u a r y ( O s a k a B a y ( F i g u r e 5. 1 ) a n d H a r i m a N a d a ) ( H a s h i m o t o e t a l ), a s w e l l a s f r o m t h e Y e l l o w a n d E a s t C h i n a S e a a n d t h e P h i l i p p i n e B a s i n ( H a s h i m o t o e t a l ) a l s o s h o w t h e d i s t i n c t i v e 1, 4 -p a t t e r n ( n o t e : T C D D s a n d P n C D D s w e r e r e p o r t e d b e l o w t h e l i m i t o f d e t e c t i o n ). T h e s e s a m p l e s i n c l u d e d t w o d a t e d s e d i m e n t c o r e s w i t h a n e s t i m a t e d d e p o s i t i o n a g e o f s e v e r a l t h o u s a n d t o m i l l i o n y e a r s. T h e 1, 4 -p a t t e r n s a r e a l s o a p p a r e n t f r o m P C D D i s o m e r p a t t e r n s p u b l i s h e d b y R a p p e e t a l. ( R a p p e e t a l a ; R a p p e e t a l b ) f r o m S o u t h e r n M i s s i s s i p p i, U. S. A., i n p a r t i cular from river s e d i m e n t ( F i g u r e 5. 1 ), d r i e d o x b o w s a m p l e s, a s w e l l a s r u r a l l a k e s e d i m e n t s. F u r t h e r, e s t u a r i n e s e d i m e n t s f r o m M a i P o M a r s h l a n d n e a r H o n g K o n g ( M ü l l e r e t a l ) are a l s o d o m i n a t e d b y 1, 4, 6, 9 -s u b s t i t u t e d i s o m e r s ( F i g u r e 5. 1 ) a n d k a o l i n i t e c l a y chromatograms from G ermany ( P ä p k e ) ( F i g u r e 5. 1 ) a n d A u s t r a l i a ( P r a n g e e t a l b ) s h o w t h e d i s t i n c t i v e 1, 4 -p a t t e r n. T h e s t r i k i n g d o m i n a n c e o f 1, 4, 6, 9 -p a t t e r n s h a s, t o m y k n o w l e d g e, n o t b e e n r e p o r t e d t o d a t e, m o s t l i k e l y d u e t o t h e h i s t o r i c a l f o c u s o n 2, 3, 7, 8 -s u b s t i t u t e d c o n g e n e r s i n e n v i r o n m e n t a l s a m p l e s. T h e s i m i l a r i t i e s o f t h e s e P C D D f i n g e r p r i n t s, i n c o m b i n a t i o n w i t h t h e o v e r a l l s i m i l a r i t i e s o f P C D D h o m o l o g u e d i s t r i b u t i o n s a n d t h e g e n e r a l l a c k o r l o w c o n c e n t r a t i o n s o f P C D F s, s t r o n g l y s u g g e s t s t h a t t r a n s f o r m a t i o n p r o c e s s e s, s i m i l a r t o t h o s e r e p o r t e d f o r Q u e e n s l a n d ( C h a p t e r 4 ) o c c u r ( o r h a v e o c c u r r e d ) in a l l t h e s e l o c a t i o n s. T h e s e p r o c e s s e s r e s u l t i n t h e f o r m a t i o n 8 0
85 C H A P T E R 5 A L T E R N A T I V E H Y P O T H E S I S o f P C D D s, i n p a r t i c u l a r O C D D a n d i t s t r a n s f o r m a t i o n t o 1, 4 -p a t t e r n s f r o m a y e t u n i d e n t i f i e d P C D D / F s o u r c e. D u e t o t h e o r i g i n o f t h e s e s a m p l e s f r o m a r e a s w i t h l i t t l e i n d u s t r i a l a c t i v i t i e s a n d/ o r h i s t o r i c a l l y o l d d e p o s i t i o n m e d i a, t w o s o u r c e s c e n a r i o s p r e s e n t a p o s s i b l e e x p l a n a t i o n f o r t h e o b s e r v e d c o n t a m i n a t i o n s : ( i ) a n a t u r a l, c o n t i n u o u s o r h i s t o r i c a l e v e n t O C D D s o u r c e, o r ( i i ) t h e i n v o l v e m e n t o f v e r t i c a l m i g r a t i o n p r o c e s s e s o f a u b i q u i t o u s O C D D d o m i n a t e d a n t h r o p o g e n i c s o u r c e NATURAL SOURCE SCENARIO A w i d e s p r e a d, n o n -a n t h r o p o g e n i c, h i s t o r i c a l e v e n t o r c o n t i n u o u s ( s i n c e a t l e a s t 3 c e n t u r i e s ) l a n d-b a s e d s o u r c e o f h i g h e r c h l o r i n a t e d P C D D s ( p r e d o m i n a n t l y O C D D ) h a s b e e n p r o p o s e d i n C h a p t e r 3 t o p o s s i b l y a c c o u n t f o r t h e P C D D s f o u n d i n s e d i m e n t s d e p o s i t e d d u r i n g t h e l a s t y e a r s. S c e n a r i o A, s c h e m a t i s e d i n F i g u r e 5. 2 A, s u m m a r i s e s t h i s h y p o t h e s i s a n d p o s t u l a t e s t h e p r e s e n c e o f a n O C D D d o m i n a t e d P C D D / F s o u r c e t h a t i ) e i t h e r h a s b e e n p r e s e n t i n t h e p a s t a n d h a s b e e n r e l a t i v e l y s t a b l e i n t h e s o i l e n v i r o n m e n t o r i i ) i s f o r m e d c o n t i n u o u s l y a n d c o n s i s t e n t l y. B o t h m a y r e s u l t i n c o n t i n u o u s a n d c o n s i s t e n t i n p u t o f h i g h e r c h l o r i n a t e d P C D D s i n t o t h e m a r i n e s y s t e m. S u b s e q u e n t d e c h l o r i n a t i o n o f O C D D, o c c u r r i n g p r e d o m i n a n t l y i n t h e s e d i m e n t e n v i r o n m e n t c o u l d r e s u l t i n t h e f o r m a t i o n o f l o w e r c h l o r i n a t e d, 1, 4, 6, 9 - d o m i n a t e d P C D D s w i t h d e p o s i t i o n a l a g e. I n t h i s s c e n a r i o, P C D D s i n s e d i m e n t s f r o m t h e d e e p e s t c o r e s e c t i o n s h a v e b e e n s u b j e c t t o l o n g-term degradat i o n a l p r o c e s s e s s i n c e t h e i r d e p o s i t i o n i n t h e m a r i n e s y s t e m, i. e. t h e P C D D / F p r o f i l e s i n t h e s u r f a c e s l i c e s o f t h e s e d i m e n t c o r e s a r e m o r e s i m i l a r t o t h e o r i g i n a l s o u r c e p r o f i l e. S c e n a r i o A i s s u p p o r t e d b y o b s e r v a t i o n s d u r i n g e a r l i e r s t u d i e s o n t h e s p a t i a l a n d t e m p o r a l P C D D d i s t r i b u t i o n i n Q u e e n s l a n d ( C h a p t e r 2 a n d 3 ). T h e s e r e s u l t s h a v e p r o v i d e d a r g u m e n t s f o r a s o u r c e i n p u t i n t o s e d i m e n t s t h a t h a v e b e e n d e p o s i t e d p r i o r t o t h e p r o d u c t i o n o f o r g a n o c h l o r i n e s a n d i n d u s t r i a l i s a t i o n. PCDD/Fs are relatively i m m o b i l e a n d s t r o n g l y s o r b e d t o t h e o r g a n i c m a t e r i a l i n t h e o r i g i n a l l a y e r o f d e p o s i t i o n. I t f o l l o w s t h a t t h e p r e s e n c e o f P C D D / F s i n d e e p s e d i m e n t l a y e r s i n d i c a t e t h e i r d e p o s i t i o n a t t h e t i m e o f s e d i m e n t a t i o n, i n t h e c a s e o f Q u e e n s l a n d, u p t o t h r e e c e n t u r i e s a g o. A l t e r n a t i v e l y, a n t h r o p o g e n i c P C D D / F p r e c u r s o r s m a y h a v e 8 1
86 C H A P T E R 5 A L T E R N A T I V E H Y P O T H E S I S t h e c a p a c i t y t o d i f f u s e t h r o u g h t h e s e d i m e n t c o l u m n a n d t h e r e f o r e a g e o f P C D D / F c o n t a m i n a t i o n w o u l d n o t n e c e s s a r i l y b e r e f l e c t e d b y d a t e o f s e d i m e n t d e p o s i t i o n ANTHROPOGENIC SOURCE SCENARIO V a r i o u s a n t h r o p o g e n i c c o m p o u n d s, i n p a r t i c u l a r c h l o r i n a t e d p h e n o l s ( C P s ) s u c h a s p e n t a c h l o r o p h e n o l ( P C P ) a n d s o d i u m p e n t a c h l o r o p h e n o l ( N a-pcp) (and their derivates e. g. p h e n o x y p h e n o l s ( H u w e e t a l )) h a v e b e e n s h o w n i n n u m e r o u s s t u d i e s t o a ) c o n t a i n l a r g e a m o u n t s o f O C D D a n d b ) t o p r o d u c e O C D D v i a b o t h b i o l o g i c a l a n d a b i o t i c p r o c e s s e s ( L a m p a r s k i e t a l ; Ö b e r g a n d R a p p e ; V o l l m u t h e t a l ; W i t t s i e p e e t a l ; H a g e n m a i e r a n d B r u n n e r ). C o n v e r s i o n o f P C P t o O C D D c a n a c h i e v e y i e l d s a s h i g h a s 2. 6 % ( C r o s b y a n d W o n g ) a n d y i e l d s o f 0. 1 % w e re f o u n d u n d e r e n v i r o n m e n t a l l y r e l e v a n t c o n d i t i o n s ( B a k e r a n d H i t e s ). T h e s e c o m p o u n d s a r e r e l a t i v e l y w a t e r-s o l u b l e d e p e n d i n g o n t h e i r i o n i s a t i o n s t a t e s i n t h e e n v i r o n m e n t, w h i c h s i g n i f i c a n t l y i m p a c t s t h e i r a q u e o u s s o l u b i l i t y, s o r p t i o n a n d t r a n s p o r t. P e n t a c h l o r o p h e n o l s o l u b i l i t y i n w a t e r r a n g e s f r o m 0. 2 g / L a t p H 5 t o g / L a t p H 1 0 ( C r o s b y e t a l ). A t p H > 7 f o r e x a m p l e, P C P i s 9 9 % d i s a s s o c i a t e d, m o v i n g e a s i l y t h r o u g h s o i l s ( C r o s b y e t a l ; S e i p e t a l ). PCP is a commo n g r o u n d w a t e r c o n t a m i n a n t ( L e e e t a l ) a n d a n u m b e r o f s t u d i e s h a v e o b s e r v e d t h a t P C P c a n b e h i g h l y l e a c h a b l e i n s o i l s a n d s e d i m e n t s ( J a c k s o n a n d B i s s o n ; H a g e n m a i e r e t a l ). E s t i m a t i o n o f t h e d if f u s i o n c o e f f i c i e n t o f P C P i n w a t e r ( D B W = cm 2 / s ), u s i n g t h e W i l k e -C h a n g e q u a t i o n ( M a c k a y e t a l ), d e m o n s t r a t e s t h a t d i s a s s o c i a t e d P C P c o u l d h a v e d i f f u s e d t o t h e d e e p e s t c o r e s e c t i o n s o f t h e s e d i m e n t c o r e s i n Q u e e n s l a n d. W h i l e t h i s d i f f u s i o n c o e f f i c i e n t i n w a t e r w i l l o v e r e s t i m a t e t h e e x t e n t o f t h e d i f f u s i o n i n s e d i m e n t p o r e w a t e r e n v i r o n m e n t s, s t u d i e s o n m i g r a t i o n o f P C P ( a q u e o u s a n d k e r o s e n e s o l u t i o n s ) i n s o i l h a v e s h o w n t h a t P C P c o l u m n b r e a k t h r o u g h o c c u r s r e l a t i v e l y r a p i d l y, i n d i c a t i n g i t s d e e p p e n e t r a t i o n i n t o s o i l c o l u m n s ( W a n g e t a l ). P C P h a s b e e n u s e d e x t e n s i v e l y a s a f u n g i c i d e a n d h e r b i c i d e s i n e t h e s ( C r o s b y e t a l ). R e l a t i v e l y h i g h c o n c e n t r a t i o n s o f P C P h a v e b e e n d e t e c t e d i n e n v i r o n m e n t a l s a m p l e s t h r o u g h o u t t h e w o r l d ( W a i t e e t a l ; L e u e n b e r g e r e t a l ; F i n g l e r e t a l ; G i f f o r d e t a l ), a n d i t h a s b e e n s u g g e s t e d t h a t, d u e t o t h e l o w e r v a p o u r p r e s s u r e o f P C P, v o l a t i l i s a t i o n f r o m a p p l i c a t i o n a r e a s m a y h a v e o c c u r r e d. V o l a t i l i s a t i o n, t o g e t h e r w i t h t h e s u b s e q u e n t c o n v e r s i o n t o O C D D ( a n d t o a l e s s e r e x t e n t 8 2
87 River sediment Hinchinbrook area Burdekin core sediment 0-2 cm Burdekin core sediment 390 cm Hinchinbrook core sediment 0-2 cm Hinchinbrook core sediment 150 cm Lake Kasumigaura sediment (PC3) Mississippi River sediment German Kaolinite clay Osaka Bay core Sediment 200 cm Hong Kong Core sediment cm % Contribution % Contribution A B / / / L HxCDD L TCDD L PnCDD LP HxCDD P HxCDD TCDDs PnCDDs HxCDDs HpCDDs / / / / / / / / / L HpCDD P HpCDD FIGURE 5.1 IS O M E R D I S T R I B U T I O N OF T E T R A - T O H E P T A C H L O R I N A T E D P C D D S IN A. Q UEENSLAND SEDIMENT CO R E S A N D R I V E R S A M P LE S F R O M T H E H INCHINBROOK AREA AND B. K ASUMIGAURA LA K E S E D I M E N T S (SA K U R A I E T A L ), MI S S I S S I P P I R I V E R S E D I M E N T S (R A P P E E T A L A ), GE R M A N K A O L I N I T E C L A Y (PÄ P K E ), OSAKA B A Y C O R E S E D I M E N T (H AS H I M O T O E T A L ) AND H ONG KONG C O R E S E D I M E N T S. (N O T E T H A T S O M E I S O M E RS COULD NOT BE OBTAIN E D F R O M T H E L I T E R A T URE ). W H I T E A R R O W S I N D I C A T E T H E P A T H W A Y O F L A T E R A L DE C H L O R I N A T I O N; BLACK ARROWS INDICAT E THE ISOMERS RESULT ING FROM LATERAL - (L), P E R I -L A T E R A L- (LP) A N D P E R I - (P) D E C H L O R I N A T I O N F R O M O C D D. N O T E : 1, 2, 3, 4, 6, 8 -H X C D D W A S C O-E L U T E D I N O SAKA B A Y C O R E S E D I M E N T S W I T H 1, 2, 4, 6, 7, 9 / 1, 2, 4, 6, 8, 9 -H X C D D.
88 C H A P T E R 5 A L T E R N A T I V E H Y P O T H E S I S t o H p C D D ), m a y r e p r e s e n t a n u b i q u i t o u s a n d p r i m a r y s o u r c e o f O C D D a n d H p C D D i n e n v i r o n m e n t a l s i n k s ( B a k e r a n d H i t e s ). T h e r e f o r e, b a s e d o n t h e r e s u l t s o f C h a p t e r 2, 3 a n d 4, a n d i n c o m b i n a t i o n w i t h t h e p o t e n t i a l f o r d i f f u s i o n a n d t r a n s f o r m a t i o n o f s u c h a n t h r o p o g e n i c O C D D p r e c u r s o r s i n d e e p s e d i m e n t s, a s e c o n d s c e n a r i o i s p r o p o s e d ( F i g u r e 5. 2 B ). S c e n a r i o B i n c l u d e s t h e d e c h l o r i n a t i o n p r o c e s s e s d i s c u s s e d i n C h a p t e r 4, b u t i n c o n t r a s t t o t h e n a t u r a l f o r m a t i o n S c e n a r i o A ( a l s o d i s c u s s e d i n C h a p t e r 3 ), p r o p o s e s t h a t a n i n p u t o f c o m m e r c i a l c h l o r o p h e n o l s ( C P s ) a n d t h e i r s u b s e q u e n t c o n v e r s i o n t o p r e d o m i n a n tl y O C D D r e s u l t i n t h e s t r o n g O C D D d o m i n a t e d p r o f i l e s o b s e r v e d i n t h e s e d i m e n t l a y e r s f r o m t h e m i d-e n d 2 0 th c e n t u r y. F r o m t h e s e s e d i m e n t s e c t i o n s h o w e v e r, d i f f u s i o n o f t h e d e p o s i t e d C P s i n t o d e e p e r ( a n d o l d e r ) s e d i m e n t l a y e r s m a y h a v e o c c u r r e d. C o n v e r s i o n o f C P s t o O C D D i n t h e s e d e e p e r s e d i m e n t s w o u l d r e s u l t i n O C D D d o m i n a t e d P C D D p r o f i l e s, a n d m a y h a v e c o n t a m i n a t e d s e d i m e n t l a y e r s t h a t h a v e b e e n d e p o s i t e d p r i o r t o t h e p r o d u c t i o n o f o r g a n o c h l o r i n e s. S u b s e q u e n t d e c h l o r i n a t i o n o f O C D D r e s u l t s i n t h e d i s t in c t i v e 1, 4 - p a t t e r n t y p i c a l o f Q u e e n s l a n d s a m p l e s PCDD/F PATTERNS IN PCP CONTAMINATED ENVIRONMENTS S u p p o r t f o r S c e n a r i o B i s f o u n d i n r e p o r t s f r o m J a p a n e s e l a k e - and tributary river s e d i m e n t s w i t h k n o w n P C P c o n t a m i n a t i o n f r o m a g r i c u l t u r a l u s e. S i m i l a r t o t h e 1, 4 - p a t t e r n d i s c u s s e d C h a p t e r 4, t h e H x C D D d i s t r i b u t i o n i n L a k e S h i n j i c o r e s e d i m e n t s ( M a s u n a g a e t a l b ) a n d s o m e L a k e K a s u m i g a u r a ( T a k a h a m a I r i ) s u r f a c e s e d i m e n t s ( S a k u r a i e t a l ) s h o w a d i s t i n c t i v e 1, 4 -p a t t e r n ( i n c l u d i n g t h e d o m i n a n c e o f 1, 2, 3, 7, 8, 9 / ( 1, 2, 3,4, 6, 7 )-H x C D D a m o n g t h e t o x i c H x C D D s ). T h e H x C D D i s o m e r p a t t e r n f r o m L a k e K a s u m i g a u r a ( T a k a h a m a I r i ) i s p r e s e n t e d i n F i g u r e 5. 1 B. I n a d d i t i o n, t h e L : P H p C D D a n d L : L P : P H x C D D r a t i o s c a l c u l a t e d f r o m r e p o r t e d P C D D / F c o n c e n t r a t i o n s i n t h e s e l a k e s a r e r e m a rk a b l y s i m i l a r t o H i n c h i n b r o o k a n d M i s s i s s i p p i r i v e r / l a k e r a t i o s ( T a b l e 5. 1 ). P r i n c i p a l c o m p o n e n t a n a l y s i s f r o m K a s u m i g a u r a L a k e / r i v e r s e d i m e n t s r e v e a l e d t h a t o n e g r o u p o f s a m p l e s w a s c h a r a c t e r i z e d b y t h e s e u n u s u a l H x C D D p a t t e r n s w h i c h c o n t r i b u t e d 1 8 % t o t he t o t a l v a r i a t i o n, b u t w h i c h c o u l d n o t b e a t t r i b u t e d t o a k n o w n s o u r c e o r t r a n s f o r m a t i o n p r o c e s s ( S a k u r a i e t a l ). I m p o r t a n t l y, i t w a s l a k e s e d i m e n t s w h i c h s h o w e d t h e u n u s u a l H x C D D p a t t e r n s, w h e r e a s p a t t e r n s i n t h e t r i b u t a r y r i v e r s e d i m e n t s c o r r e l a t e d t o 8 4
89 C H A P T E R 5 A L T E R N A T I V E H Y P O T H E S I S p r i n c i p a l c o m p o n e n t s r e p r e s e n t i n g P C P a n d / o r c h l o r o n i t r o p h e n ( C N P ) i m p u r i t i e s u s e d i n r i c e p a d d y c u l t i v a t i o n s o f t h e a r e a. T h e a u t h o r s s u g g e s t ed t h a t e i t h e r s o m e i n p u t o r l a c k o f s o m e l o s s / t r a n s f o r m a t i o n c o u l d h a v e r e s u l t e d i n t h e s e l a k e s e d i m e n t s i g n a t u r e s. S t u d i e s o n t r a n s f o r m a t i o n p r o c e s s e s i n Q u e e n s l a n d ( C h a p t e r 4 ) s u p p o r t t h i s, a n d s u g g e s t t h a t d e c h l o r i n a t i o n o f O C D D d e r i v e d f r o m t h e e x t ensive PCP input, may have resulted i n t h e t r a n s f o r m a t i o n o f L a k e K a s u m i g a u r a s e d i m e n t P C D D s i g n a t u r e s. C o r e s e d i m e n t s f r o m L a k e S h i n j i a l s o s h o w e d h i g h P C D D / F c o n t r i b u t i o n s ( a v e r a g e 6 8 % ) f r o m P C P i m p u r i t i e s. P C P w a s u s e d e x t e n s i v e l y i n t h e a r e a a s a r i c e p a d d y h e r b i c i d e i n t h e a r e a d u r i n g t h e s a n d s ( M a s u n a g a e t a l b ). A p a r t f r o m t h e c h a r a c t e r i s t i c 1, 4 -p a t t e r n s p r e s e n t i n t h e c o r e s a m p l e s, i t i s p a r t i c u l a r l y i n t e r e s t i n g t h a t t h e P C D D / F c o n c e n t r a t i o n s i n t h e d a t e d s e d i m e n t c o r e i n c r e a s e d s e v e r a l y e a r s a h e a d o f P C P u s e. S e d i m e n t s d e p o s i t e d d u r i n g t h e t i m e o f P C P a p p l i c a t i o n s h o w e d r e l a t i v e l y h i g h P C D F c o n c e n t r a t io n s, a n d l o w P C D D : P C D F ( D / F ) r a t i o s ( 1 1 t o 1 4 ), c o r r e s p o n d i n g w e l l w i t h D / F r a t i o s r e p o r t e d f r o m P C P f o r m u l a s ( H a g e n m a i e r a n d B r u n n e r ). O l d e r s e d i m e n t s, d e p o s i t e d b e f o r e t h e a p p l i c a t i o n o f P C P, s h o w e d r e l a t i v e l y h i g h P C D D c o n c e n t r a t i o n s ( > p g g - 1 d w ), h o w e v e r, P C D F c o n c e n t r a t i o n s w e r e c o n s i d e r a b l y l o w e r, r e s u l t i n g i n a D / F r a t i o o f u p t o 8 2 i n t h e d e e p e s t s e d i m e n t l a y e r. C o n s i d e r i n g t h e h i s t o r y o f l a n d -u s e i n t h i s a r e a, i t s e e m s p o s s i b l e t h a t t h i s t r e n d m a y b e d u e t o t h e f o r m a t i o n o f h i g h e r c h l o r i n a t e d P C D D s a f t e r m i g r a t i o n o f P C P i n t o d e e p e r s e d i m e n t l a y e r s, w h e r e a s P C D D / F i m p u r i t i e s o r i g i n a l l y p r e s e n t i n P C P a r e r e l a t i v e l y i m m o b i l e, a n d s o r b e d s t r o n g l y t o t h e o r g a n i c m a t e r i a l i n t h e o r i g i n a l s e d i m e n t l a y e r o f d e p o s i t i o n. A s u b s e q u e n t l o n g-t e r m d e c h l o r i n a t i o n o f n e w l y f o r m e d O C D D c a n r e s u l t i n t h e f o r m a t i o n o f t h e c h a r a c t e r i s t i c 1, 4, 6, 9 -i s o m e r s a s s u g g e s t e d b y t h e r e s u l t s p r e s e n t e d i n C h a p t e r 4. O C D D c o n d e n s a t i o n f r o m P C P m a y a l s o e x p l a i n t h e d i s c r e p a n c i e s o b s e r v e d i n L a k e S h i n j i s e d i m e n t s w i t h r e s p e c t t o m a s s b a l a n c e e s t i m a t i o n s. T h e r a t i o o f P C D D / F s l o s t f r o m s o i l t o t h a t o f t h e e m i s s i o n i n p u t, a n d t h e r a t i o s o f P C D D / F s d e p o s i t e d i n t h e l a k e s e d i m e n t s t o t h a t l o s t f r o m t h e b a s i n w a s c o n s i d e r a b l y h i g h e r f o r P C P- c o m p a r e d t o C N P-c a l c u l a t e d P C D D / F s i m p u r i t i e s ( M a s u n a g a e t a l b ). It has been suggested t h a t t h e c o n v e r s i o n o f P C P t o O C D D ( a n d t o a l e s s e r e x t e n t H p C D D ) i n t h e e n v i r o n m e n t m a y b e c a u s e f o r t h e l a r g e d i s c r e p a n c i e s i n a t m o s p h e r i c P C D D / F e m i s s i o n a n d d e p o s i t i o n e s t i m a t e s f o r m a s s b a l a n c e e s t i m a t i o n s a r o u n d t h e w o r l d ( B a k e r a n d H i t e s ). E s t i m a t e s s u g g e s t e d t h a t p h o t o c h e m i c a l P C P c o n v e r s i o n 8 5
90 A Old C H A P T E R 5 A L T E R N A T I V E H Y P O T H E S I S Continuous or discontinued formation of higher chlorinated PCDDs Recent Initial deposition: soil Final sink: marine sediments Sediment core B Old Higher chlorinated PCDDs Lower chlorinated PCDDs Input of CP + OCDD impurities Recent Diffusion of CP and formation of OCDD Formation of OCDD Final sink: marine sediments Diffusion of CP and formation of OCDD Sediment core Higher chlorinated PCDDs Lower chlorinated PCDDs FIGURE 5.2 SCHEMATIC OF DECHLORINATION PROCESSES OF HIGHER CHLORINATED P C D DS A N D T H E R E S U L T A N T P R O D U C T I O N O F L O W E R CHLORINATED P C D DS W I T H T I M E O F D E P O S I T I O N I N T HE S E D I M E N T E N V I R O N M EN T T O R E S U L T I N T H E H O M O L O GUE SHIFT OBSERVED IN T H E S E D I M E N T C O R E S. SCENARIO A P O S T U L A T E S T H E D E P O S I T I O N O F M A I N L Y H I G H ER CHLORINATED P C D DS ON LAND, T H E I R S U B S E Q U E N T T R AN S P O R T A N D D E C H L O R I N A T I O N I N T H E MARINE ENVIRO N M E N T. SCENARIO B P O S T U L A T E S T H E D E P O S I T I O N O F A N T H R O P O G E N IC C PS (A N D T H E I R D E R I V A T I V E S) D U R I N G T H E M I D 2 0 T H C E N T U R Y, T H E I R T R A N S P O R T A N D M I G R A T I O N I N T O D E E P S E D I M E N T L A Y E R S, AND SUBSEQUENT FORMATION AND DECHLO R I N A T I O N O F O C D D I N T H E M A R I N E E N V I R O N M E N T. 8 6
91 C H A P T E R 5 A L T E R N A T I V E H Y P O T H E S I S processes i n t h e a t m o s p h e r e c a n c l o s e t h e m a s s b a l a n c e f o r b o t h O C D D a n d H p C D D ( B a k e r a n d H i t e s ) PCP APPLICATION IN AUSTRALIA E n q u i r i e s r e g a r d i n g q u a n t i t i e s o f C P a p p l i c a t i o n w i t h i n t h e c o a s t l i n e o f Q u e e n s l a n d o r A u s t r a l i a h a v e n o t r e s u l t e d i n r e l i a b l e q u a n t i t a t i v e d a t a t o d a t e. P C P h a s b e e n p r o d u c e d i n A u s t r a l i a ( u n t i l t h e m i d s ), i m p o rt e d i n t o Q u e e n s l a n d, a n d u s e d f o r p r e s e r v a t i o n o f t i m b e r ( K o o k a n a e t a l ; A B S ). H i s t o r i c a l o r c o n t e m p o r a r y u s e w i t h i n a g r i c u l t u r a l a r e a s i s u n k n o w n a t t h i s s t a g e. I t i s n o t e w o r t h y, h o w e v e r, t h a t r e c e n t s tu d i e s o n f o r e s t s o i l c o r e s i n Q u e e n s l a n d h a v e d e m o n s t r a t e d t h a t O C D D a n d H p C D D a r e p r e s e n t a l m o s t e x c l u s i v e l y u p t o 3 m d e e p s o i l l a y e r s, w h i l e t h e s u r f a c e s e c t i o n s s h o w P C D D c o n g e n e r s t y p i c a l f o r Q u e e n s l a n d p r o f i l e s, a n d P C D F s t h a t i n d i c a t e P C P c o n t a m i n a t i o n ( P r a n g e e t a l a ) Years (Burdekin Core) Burdekin Core Hinchinbrook Core Years (Hinchinbrook Core) 0 0 OCDD Total HpCDD Total HxCDD Total PnCDD Total TCDD FIGURE 5.3 ES T I M A T E D T I M E O F D I S A P P E A R A N C E O F O C D D A N D T I M E O F A P P E A R A N C E O F L O W E R CHLORINATED P C D D S USING THE SLOPES O B T A I N E D F R O M T H E R E LATIVE DECREASE OF O C D D A N D R E L A T I V E DECREASE OF LOWER CHL O R I N A T E D T E T R A - T O H E P T A C H L O R I N A T ED P C D DS WITH INCREASING SE D I M E N T A T I O N A G E I N B URDEKIN AND H INCHINBROOK CORE SED I M E N T S (SEE C H A P T E R 4), A S S U M I N G T H E F O R M A T I O N O F P C D DS 4 0 YEARS FROM PRESENT. 8 7
92 C H A P T E R 5 A L T E R N A T I V E H Y P O T H E S I S T h e ( p r e d o m i n a n t ) O C D D f o r m a t i o n f r o m d i f f u s e d P C P c o u l d e x p l a i n t h e l o w e r P C D F c o n c e n t r a t i on s i n s a m p l e s f r o m Q u e e n s l a n d, a s P C P h a s b e e n s h o w n t o p r o d u c e p r e d o m i n a n t l y O C D D a n d t o a l e s s e r e x t e n t H p C D D s, w h e r e a s b o t h P C D D s a n d P C D F s a r e t y p i c a l l y p r e s e n t i n P C P o n l y a s i m p u r i t i e s ( H a g e n m a i e r a n d B r u n n e r ; M a s u n a g a e t a l a ). F u r t h e r, i n t h i s s c e n a r i o, t i m e s o f O C D D d i s a p p e a r a n c e ( a p p r o x i m a t e l y y e a r s ) a n d P C D D a p p e a r a n c e ( a p p r o x i m a t e l y y e a r s f o r Σ T C D D s ) ( F i g u r e 5. 3 ) a r e a n o r d e r o f m a g n i t u d e h i g h e r w h e n c o m p a r e d t o e s t i m a t e s u s i n g t h e a c t u a l y e a r s s e d i m e n t d e p o s i t i o n p e r i o d s i n S c e n a r i o A ( c a l c u l a t e d i n C h a p t e r 4, u s i n g t h e r e l a t i v e c o n c e n t r a t i o n c h a n g e s w i t h a g e a s a p r o x y f o r h a l f -l i f e ). T h i s i s d u e t o t h e c o n s i d e r a b l y s h o r t e r d e p o s i t i o n p e r i o d s ( y e a r s ) i n t h e c a s e o f S c e n a r i o B. T h e s e s h o r t e r e s t i m a t e s a r e a l s o m o r e c o m p a r a b l e t o e s t i m a t e d h a l f -l i v e s o f O C D D a n d t h e r a t e s o f a p p e a r a n c e o f l o w e r c h l o r i n a t e d P C D D / F s d u r i n g d e c h l o r i n a t i o n p r o c e s s e s i n t h e l i t e r a t u r e ( M a c k a y e t a l ; K j e l l e r a n d R a p p e ; E i s e n b e r g, B e n n e t t ; S e g s t r o e t a l ; A l b r e c h t e t a l ; F u e t a l ). C o n s i d e r i n g a l l p r e s e n t k n o w l e d g e a b o u t t h e P C D D c o n t a m i n a t i o n i n Q u e e n s l a n d, a l a n d-b a s e d s o u r c e o f p r i m a r i l y O C D D ( a n d / o r O C D D p r e c u r s o r s ) s e e m s m o s t p r o b a b l e. A s u b s e q u e n t t r a n s f o r m a t i o n v i a d e c h l o r i n a t i o n a f t e r O C D D f o r m a t i o n ( a n d f o r S c e n a r i o B m i g r a t i o n a n d c o n d e n s a t i o n ) i s l i k e l y t o r e s u l t i n t h e a c c u m u l a t i o n o f l o w e r c h l o r i n a t e d P C D D s, i n p a r t i c u l a r t h e p e r i -c h l o r i n a t e d i s o m e r s p r o d u c i n g t h e c h a r a c t e r i s t i c 1, 4 -p a t t e r n s o b s e r v e d a l o n g t h e Q u e e n s l a n d c o a s t l i n e. W i t h t h e p r e s e n t k n o w l e d g e p r o v i d i n g l i m i t e d e v i d e n c e f o r b o t h h y p o t h e s e s, h o w e v e r, i t c a n n o t b e e l u c i d a t e d i f t h e s o u r c e i n p u t i s o f a n t h r o p o g e n i c o r n o n -a n t h r o p o g e n i c o r i g i n. C l e a r l y a n d i m p o r t a n t l y t h o u g h, t h e p r e s e n t e x e r c i s e h i g h l i g h t s t h a t t h e p o s s i b i l i t i e s f o r t h e o b s e r v e d c o n t a m i n a t i o n s a r e n o t o n l y l i m i t e d t o h i s t o r i c a l l y o l d a n d n a t u r a l l y o c c u r r i n g f o r m a t i o n p r o c e s s e s. I t i s t h e r e f o r e c r i t i c a l t h a t t h e i d e n t i f i c a t i o n a n d c o n v e r s i o n o f P C D D / F p r e c u r s o r s i n t h e e n v i r o n m e n t r e c e i v e s m o r e s c i e n t i f i c a t t e n t i o n, i n o r d e r t o q u a n t i f y i t s c o n t r i b u t i o n t o t h e c o n t a m i n a t i o n s i n a r e a s w h e r e 1, 4 - p a t t e r n s h a v e b e e n o b s e r v e d. 8 8
93 C H A P T E R 5 A L T E R N A T I V E H Y P O T H E S I S TABLE 5.1 R A T I O S O F L A T E R A L D E C HLORINATED (L) AND PERI DECHLORINAT ED (P) H P C D D S (I. E. 1, 2, 3, 4, 6, 7, 9 -H P C D D : 1, 2, 3, 4, 6, 7, 8 -H P C D D ) AND L : LP : P HX C D DS (I.E. 1, 2, 4, 6, 7, 9 / 1, 2, 4, 6, 8, 9 -H X C D D : 1, 2, 3, 6, 7, 9 -/ 1, 2, 3, 6, 8, 9 - H X C D D : 1, 2, 3, 6, 7, 8 -/ 1, 2, 3, 7, 8, 9 -/ 1, 2, 3, 4, 6, 7 -H X C D D ) AND % C O N T R I B U T I O N O F L PN C D D (I. E. 1, 2, 4, 6, 9 -PNC D D ) AND L TCDD (I. E. 1, 4, 6, 9 -T C D D ) T O T H E Σ H O M O L O G U E G R O U P I N A R A N G E O F S A M P L E S F R O M Q UEENSLAND AND ELSEWHERE. L : P HpCDD L : L P : P HxCDD % L PnCDD % L TCDD Lake and river sediments River, Hinchinbrook area a 2 : 1 4 : 1 : Mississippi Lake (bottom) b n a ~34 : 2 : 1 n a na Mississippi River (Pascagoula) c ~2 : 1 ~4 : 2 : 1 ~33 na Mississippi Lake (Rogue Homa) b n a ~4 : 2 : 1 n a na K a o l i n i t e c l a y German kaolinite clay a 2 : 1 5 : 2 : Lake sediments with known PCP input Lake Kasumigaura(Takahama Iri) d na ~4 : 2 : 1 n a na Lake Shinji (25-26 cm) e 2 : 1 4 : 2 : a P r e s e n t s t u d y b Calculated from isomer distribution published in (Rappe at al. 1997b) c Calculated from isomer distribution published in (Rappe et al. 1997a) d Calculated from isomer distribution published in (Sakurai et al. 1998) e Calculated from PCDD concentrations published in (Masunaga et al. 2001b) n a not available n d n o t d e t e c t e d 8 9
94 CHAPTER 6 FATE OF DIOXINS Contamination of the inshore sediment-seagrass-dugong system In parts published in: Organohalogen Compounds 2001 (Volume 52, pages ); Environmental Toxicology and Chemistry 2003 (submitted)
95 C H A P T E R 6 FA T E A N D T R A N S P O R T ABSTRACT P o l y c h l o r i n a t e d d i b e n z o -p -d i o x i n s a n d d i b e n z o f u r a n s ( P C D D / F s ) a r e l i p o p h i l i c, p e r s i s t e n t o r g a n i c p o l l u t a n t s t h a t a c c u m u l a t e i n a q u a t i c e c o s y s t e m s, i n c l u d i n g b i o t a. P r e v i o u s i n v e s t i g a t i o n s h a v e d e t e r m i n e d e l e v a t e d c o n c e n t r a t i o n s o f P C D D / F s a l o n g t h e c o a s t l i n e o f Q u e e n s l a n d, A u s t r a l i a, i n c l u d i n g t h e n e a r s h o r e e c o s y s t e m s o f t h e w o r l d h e r i t a g e G r e a t B a r r i e r R e e f M a r i n e P a r k. T h i s e c o s y s t e m s u p p o r t s u n i q u e f a u n a a n d f l o r a s u c h a s t h e m a r i n e h e r b i v o r o u s m a m m a l d u g o n g (D u g o n g d u g o n ) a n d i t s f o o d s o u r c e, s e a g r a s s. T h i s s t u d y i n v e s t i g a t e d t h e f a t e o f P C D D / F s i n t h e s e d i m e n t-seagrassd u g o n g e c o s y s t e m. S p e c i f i c a l l y, P C D D / F t r a n s p o r t, a n d c o n g e n e r s p e c i f i c re d i s t r i b u t i o n, u p t a k e, a b s o r p t i o n, m e t a b o l i s m, r e t e n t i o n a n d t r a n s f e r p a t h w a y s o r p r o c e s s e s w e r e a s s e s s e d. S e d i m e n t r u n o f f f r o m r i v e r t r i b u t a r i e s a p p e a r e d t o p r o v i d e t h e m a j o r t r a n s p o r t p a t h w a y o f l a n d -b a s e d P C D D / F s. S e d i m e n t -w a t e r p a r t i t i o n i n g p r o c e s s e s a r e p r o p o s e d t o r e s u l t i n a c c u m u l a t i o n o f P C D D / F s o n s e a g r a s s, a n d r e s u l t i n a n i n c r e a s e i n t o x i c e q u i v a l e n c y ( T E Q ) c o m p a r e d t o s e d i m e n t. T h e e x t e n t o f t h e s e d i m e n t P C D D / F c o n t a m i n a t i o n g o v e r n s t h e c o n c e n t r a t i o n s o n s e a g r a s s, a s w e l l a s d u g o n g b o d y b u r d e n s. H i g h s e a g r a s s ( a n d i n c i d e n t a l s e d i m e n t ) i n g e s t i o n r a t e s, s e l e c t i v e r e t e n t i o n o f t o x i c o l o g i c a l l y p o t e n t c o n g e n e r s a n d r e l a t i v e l y l o w P C D D / F e l i m i n a t i o n c a p a c i t i e s i n d u g o n g s a r e p r o p o s e d t o r e s u l t i n t h e o b s e r v e d a c c u m u l a t i o n o f e l e v a t e d P C D D / F c o n c e n t r a t i o n s a n d T E Q l e v e l s i n t h e a n i m a l s. T r a n s f e r e f f i c i e n c i e s o f u p t o 4 a n d 2 7 % o f m a t e r n a l T E Q l e v e l s t o f o e t u s e s a n d c a l v e s ( r e s p e c t i v e l y ) w e r e d e t e r m i n e d, a n d r e s u l t i n r e l a t i v e l y h i g h e x p o s u r e l e v e l s i n o f f s p r i n g. C o m p a r e d t o n o- observed -adverse -e f f e c t-l e v e l s i n o t h e r m a m m a l s, a n d b a s e d o n t h e r e s u l t s o f t h i s s t u d y, a t o l e r a b l e d a i l y i n t a k e o f p g T E Q k g - 1 d a y - 1 w a s e s t i m a t e d f o r d u g o n g s. E s t i m a t e s o n a v e r a g e d a i l y P C D D / F i n t a k e i n d i c a t e t h a t d u g o n g s a l o n g t h e c o a s t l i n e o f Q u e e n s l a n d e x c e e d t h i s T D I b y u p t o 2 0 f o l d. T h e s e r e s u l t s s u g g e s t t h a t, t o g e t h e r w i t h o t h e r p r e s s u r e s, t h e d u g o n g p o p u l a t i o n s m a y b e a t r i s k f r o m P C D D / F c o n t a m i n a t i o n i n t h e i r h a b i t a t. 9 1
96 C H A P T E R 6 FA T E A N D T R A N S P O R T 6.1 INTRODUCTION P o l y c h l o r i n a t e d d i b e n z o -p -d i o x i n s a n d d i b e n z o f u r a n s ( P C D D / F s ) a r e p e r s i s t e n t o r g a n i c p o l l u t a n t s ( P O P s ), e m i t t e d f r o m n u m e r o u s i n d u s t r i a l a n d c h e m i c a l p r o c e s s e s, a n d a r e u b i q u i t o u s l y d i s t r i b u t e d i n t h e e n v i r o n m e n t. A l o n g t h e i r v a r i o u s t r a n s p o r t p a t h w a y s, P O P s p a r t i t i o n b e t w e e n g a s e o u s, l i q u i d a n d p a r t i c l e p h a s e s, w h i c h p e r m i t s t h e i r cycling b e t w e e n t h e e n v i r o n m e n t a l c o m p a r t m e n t s o f a i r, s o i l, w a t e r, a n d b i o t a ( C o n n e l l a n d H a w k e r ; C o n n e l l ; W a n i a a n d M a c k a y ). T h e s e p a t h w a y s a r e strongly d e p e n d e n t o n t h e p h y s i c o -c h e m i c a l p r o p e r t i e s o f i n d i v i d u a l P O P s, w h i c h g o v e r n t h e i r f a t e i n t h e e n v i r o n m e n t. W h i l e P C D D / F d i s t r i b u t i o n o c c u r s p r e d o m i n a n t l y v i a a t m o s p h e r i c t r a n s p o r t p a t h w a y s ( C z u c z w a a n d H i t e s ), t h e i r s t r o n g a f f i n i t y f o r p a r t i c u l a t e s a l s o r e s u l t s i n s i g n i f i c a n t s e d i m e n t / s o i l a s s o c i a t e d t r a n s p o r t f r o m l o c a l p o i n t s o u r c e s a n d s o u r c e -i m p a c t e d t r i b u t a r i e s ( E i t z e r ; P e a r s o n e t a l ). B o t h t r a n s p o r t r o u t e s u l t i m a t e l y l e a d t o a c c u m u l a t i o n o f P C D D / F s i n a q u a t i c s e d i m e n t s ( C z u c z w a a n d H i t e s ), w h i c h i n t u r n r e p r e s e n t a n i m p o r t a n t c o m p a r t m e n t f o r t h e i r r e d i s t r i b u t i o n i n t o b i o t a ( S e g s t r o e t a l ; F r o e s e e t a l ). D u e t o t h e i r t o x i c i t y a n d p e r s i s t e n t n a t u r e, P O P s s u c h a s P C D D / F s a r e c o n s i d e r e d a s e r i o u s t h r e a t t o e c o s y s t e m h e a l t h, p a r t i c u l a r l y w i t h r e s p e c t t o t he p o t e n t i a l f o r t o x i c c o n g e n e r s t o b i o a c c u m u l a t e i n b i o t a, b i o m a g n i f y t h r o u g h t h e f o o d w e b, a n d t r a n s f e r t o o f f s p r i n g v i a g e s t a t i o n a n d l a c t a t i o n i n m a m m a l s ( T a n a b e e t a l ; D e G u i s e e t a l ). I n p a r t i c u l a r, m a n y m a r i n e m a m m a l s a r e c o n s i d e r e d a m o n g s t t h e o r g a n i s m s m o s t v u l n e r a b l e t o a d v e r s e h e a l t h e f f e c t s f r o m P O P s, d u e t o a c c u m u l a t e d l e v e l s i n t h e i r e n v i r o n me n t, t h e i r h i g h f a t r e p o s i t o r i e s a n d p o s i t i o n i n t h e f o o d c h a i n ( T a n a b e ; B o r r e l l e t a l ; R o s s e t a l ), a s w e l l a s r e d u c e d m e t a b o l i c c a p a c i t i e s f o r c e r t a i n c o m p o u n d s ( T a n a b e e t a l ; K a n n a n e t a l ). Exposu r e o f m a r i n e m a m m a l s t o P O P s, h a s b e e n i m p l i c a t e d i n a r a n g e o f a d v e r s e e f f e c t s s u c h a s c a r c i n o g e n i c i t y, t e t r a t o g e n i c i t y, s t e r i l i t y, i m p a i r m e n t o f i m m u n o l o g i c a l r e s p o n s e s, d e v e l o p m e n t a l a n d r e p r o d u c t i v e a b n o r m a l i t i e s ( s u m m a r i s e d i n (CSTEE - C o m m i t t e e o n T o x i c i t y ; R o s s )). A s i g n i f i c a n t a n d w i d e s p r e a d P C D D / F c o n t a m i n a t i o n h a s b e e n d e m o n s t r a t e d a l o n g t h e p r e d o m i n a n t l y r u r a l, k m l o n g t r o p i c a l / s u b t r o p i c a l c o a s t a l z o n e o f Q u e e n s l a n d, A u s t r a l i a ( C h a p t e r 2 ; P r a n g e e t a l b ). T h e s e s t u d i e s h a v e s h o w n t h a t t h e s o u r c e i s l a n d-b a s e d a n d s i m i l a r i n a l l r e g i o n s, c h a r a c t e r i s t i c a l l y d o m i n a t e d b y O C D D w i t h 9 2
97 C H A P T E R 6 FA T E A N D T R A N S P O R T P C D F s p r e s e n t a t l o w c o n c e n t r a t i o n s o r b e l o w t h e l i m i t o f d e t e c t i o n. W h i l e a n a l y s i s o f d a t e d s e d i m e n t c o r e s i n d i c a t e d t h a t f o r m a t i o n o f P C D D s m a y b e o f n a t u r a l o r i g i n ( C h a p t e r 3 ), a n a l t e r n a t i v e h y p o t h e s i s h a s a l s o b e e n p o s t u l a t e d, w h e r e b y p r e c u r s o r s, s u c h a s p e n t a c h l o r o p h e n o l a n d i t s d e r i v a t e s, a r e p o t e n t i a l o r i g i n s f o r t h e o b s e r v e d c o n t a m i n a t i o n ( C h a p t e r 5 ). R e l a t i v e l y l i t t l e i s k n o w n, h o w e v e r, a b o u t t h e p a t h w a y s o f t h e s e c o n t a m i n a n t s w i t h i n t h e Q u e e n s l a n d i n s h o r e c o a s t a l e c o s y s t e m a n d t h e i r p o t e n t i a l a c c u m u l a t i o n i n b i o t a. Q u e e n s l a n d s m a r i n e s y s t e m s u s t a i n s n u m e r o u s a n d d i v e r s e f a u n a a n d f l o r a, m a n y a s s o c i a t e d w i t h t h e w o r l d h e r i t a g e G r e a t B a r r i e r R e e f M a r i n e P a r k. T h e s e b i o t a i n c l u d e e x t e n s i v e s e a g r a s s h a b i t a t s t h a t r e p r e s e n t a m a j o r f o o d s o u r c e f o r t h e u n i q u e m a m m a l d u g o n g (D u g o n g d u g o n), l i s t e d a s v u l n e r a b l e t o e x t i n c t i o n (IUCN ). T h e d u g o n g i s t h e o n l y s t r i c t l y m a r i n e h e r b i v o r e m a m m a l a n d r e p r e s e n t s t h e l a s t e x t a n t s p e c i e s i n t h e f a m i l y D u g o n g i d a e o f t h e o r d e r S i r e n i a, t h e l a t t e r a l s o i n c l u d i n g t h r e e s p e c i e s o f m a n a t e e. D u g o n g s a r e l a r g e m a m m a l s ( u p t o 3 m, k g ) w i t h h i g h f a t r e p o s i t o r i e s t h a t f r e q u e n t c o a s t a l w a t e r s w i t h h a b i t a t s p r e d o m i n a n t l y i n w i d e s h a l l o w p r o t e c t e d b a y s ( M a r s h e t a l ). I n Q u e e n s l a n d, t h e i r h o m e r a n g e i s r e l a t i v e l y s m a l l, r a n g i n g f r o m 5 t o 6 4 k m 2 ( P r e e n ). D ug o n g s h a v e a l o n g l i f e-s p a n ( ~ 7 0 y e a r s ), l o w r e p r o d u c t i v e r a t e a n d r e l a t i v e l y l o n g g e s t a t i o n ( 1 3 m o n t h s ) a n d l a c t a t i o n ( 1 8 m o n t h s ) p e r i o d s ( M a r s h e t a l ). T h e y a r e h i n d g u t f e r m e n t e r s w i t h h i g h l y s p e c i a l i s e d d i e t a r y r e q u i r e m e n t s, u p r o o t i n g w h o l e s e a g r a s s p l a n t s a n d o f t e n s e l e c t i v e l y f o r a g i n g o n a f e w p i o n e e r s e a g r a s s s p e c i e s s u c h a s H a l o p h i l a a n d H a l o d u l e ( M a r s h e t a l ). L o w m e t a b o l i c r a t e s, h i g h s e a g r a s s c o n s u m p t i o n r a t e s a n d i n o r d i n a t e l y l o n g p a s s a g e t i m e s o f d i g e s t a t h r o u g h t h e g u t ( ~ 6-7 days) (Lanyon 1991), c o m p e n s a t e f o r t h e l o w n u t r i e n t c o n t a i n i n g s e a g r a s s d i e t. I n a d d i t i o n t o t h e i r c o n s e r v a t i o n s i g n i f i c a n c e o n a t a x o n o m i c a n d e c o l o g i c a l s c a l e, d u g o n g s a l s o p r o v i d e i m p o r t a n t c u l t u r a l v a l u e s f o r m a n y i n d i g e n o u s c o m m u n i t i e s. D u e t o t h e i r b i o l o g y a n d d e p e n d e n c e o n i n s h o r e c o a s t a l h a b i t a t s, d u g o n g s a r e e x p o s e d t o n u m e r o u s a n t h r o p o g e n i c i n f l u e n c e s ( M a r s h e t a l ). I n c r e a s e d a c t i v i t i e s i n t h e c o a s t a l z o n e o f Q u e e n s l a n d, b ot h i n t e r m s o f p o p u l a t i o n a n d a g r i c u l t u r a l p r a c t i c e s, p l a c e p r e s s u r e s o n n e a r s h o r e m a r i n e e c o s y s t e m s ( A S E C ). T h r e a t e n i n g p r o c e s s e s t o d u g o n g s i n c l u d e h a b i t a t l o s s, n e t e n t a n g l e m e n t, v e s s e l s t r i k e s a n d d i s e a s e ( M a r s h e t a l ). P r e v i o u s s t u d i e s h a v e a l s o r e p o r t e d t h e p r e s e n c e o f e l e v a t e d P C D D / F 9 3
98 C H A P T E R 6 FA T E A N D T R A N S P O R T c o n c e n t r a t i o n s i n t h r e e d u g o n g s f r o m Q u e e n s l a n d ( H a y n e s e t a l ; M c L a c h l a n e t a l ). Among the va r i o u s p r e s s u r e s o n d u g o n g p o p u l a t i o n s, h o w e v e r, l i t t l e i s k n o w n a b o u t t h e e x t e n t o f e x p o s u r e t o p e r s i s t e n t o r g a n i c p o l l u t a n t s i n t h e p o p u l a t i o n, t h e i r t r a n s p o r t p a t h w a y s a n d p r o c e s s e s w i t h i n t h e a n i m a l a n d t h e p o t e n t i a l r i s k s a s s o c i a t e d w i t h t h e p r e s e n c e o f P C D D / F s i n t h e d u g o n g s h a b i t a t. T h e p r e s e n t s t u d y a i m e d t o p r o v i d e i n f o r m a t i o n o n t h e t r a n s p o r t p a t h w a y s a n d p r o c e s s e s o f P C D D / F s w i t h i n t h e i n s h o r e s e d i m e n t -seagrass -dugong ecosystem, and to e s t a b l i s h a b a s e l i n e e s t i m a t e f o r P C D D / F c o n c e n t r a t i o n s i n d u g o n g s f r o m Q u e e n s l a n d. L o n g l i f e s p a n, h i g h f a t r e p o s i t o r y, n a r r o w h o m e r a n g e s a n d h i g h l y s p e c i a l i s e d f o o d r e q u i r e m e n t s r e n d e r t h e d u g o n g p o t e n t i a l l y v u l n e r a b l e t o t h e r e g i o n a l P C D D / F c o n t a m i n a t i o n i n Q u e e n s l a n d. A l l t h e s e f e a t u r e s o f t h e d u g o n g, h o w ever, in c o m b i n a t i o n w i t h t h e p r e s e n c e o f a w i d e s p r e a d, s p e c i f i c s i n g l e P C D D / F s o u r c e p r o f i l e i n t h e Q u e e n s l a n d e n v i r o n m e n t, p r o v i d e a r e l a t i v e l y s i m p l e m a t r i x t o d e v e l o p a n u n d e r s t a n d i n g o f t h e f a t e o f P C D D / F s w i t h i n t h i s s e d i m e n t -b i o t a s y s t e m. 6.2 MATERIALS AND METHODS SAMPLING T i s s u e s a m p l e s f r o m d u g o n g s w e r e o b t a i n e d f r o m a n i m a l s f o u n d d e a d ( s t r a n d e d, e n t a n g l e d i n s h a r k n e t s o r o t h e r w i s e d i s e a s e d ) w i t h i n s i x r e g i o n s a l o n g t h e c o a s t l i n e o f Q u e e n s l a n d ( F i g u r e 6. 1 ). W i t h i n t h e s e r e g i o n s, s u b t r o p i c a l / t r o p i c a l river systems flow i n t o t h e i n s h o r e m a r i n e e n v i r o n m e n t ( F i g u r e 6. 1 ). B l u b b e r s a m p l e s w e r e t a k e n f r o m t h e o u t e r l a y e r o f b l u b b e r f r o m a d u l t m a l e s ( n = 8 ), a d u l t f e m a l e s ( n = 1 5 ), c a l v e s ( n = 1 0 ) a n d f o e t u s e s ( n = 2 ). S e d i m e n t a n d s e a g r a s s ( r o o t s, r h i z o m e s a n d le a v e s o f H a l o p h i l a o v a l i s ( n = 6 ), H a l o d u l e u n i n e r v i s ( n = 1 ), Zostera c a p r i c o r n i ( n = 1 ) a n d C y m o d o c e a s e r r u l a t a ( n = 1 ) w e r e o b t a i n e d f r o m s u b t i d a l s i t e s w i t h i n k n o w n d u g o n g f e e d i n g a r e a s f r o m R e g i o n 5 a n d 6 a n d a n a d d i t i o n a l s i t e ( G l a d s t o n e, F i g u r e 6. 1 ). S u r f a c e s e d i m e n t s w e r e c o l l e c t e d u s i n g a m o d i f i e d V a n V e e n g r a b s a m p l e r. A l l s a m p l e s w e r e c o l l e c t e d a n d h a n d l e d u s i n g s t a i n l e s s s t e e l o r g l a s s m a t e r i a l s ( e x c e p t f o r t h e h a n d-c o l l e c t i o n o f s e a g r a s s ) a n d w e r e s t o r e d f r o z e n u n t i l p r o c e s s i n g. 9 4
99 C H A P T E R 6 FA T E A N D T R A N S P O R T BIOTA ANALYSIS D u g o n g b l u b b e r a n d s e a g r a s s s a m p l e s w e r e a n a l y s e d f o r 2, 3, 7, 8 -s u b s t i t u t e d P C D D / F p r o f i l e s a t E r g o F o r s c h u n g s g e s e l l s c h a f t m b H ( E R G O ) i n G e r m a n y. S e a g r a s s w a s w a s h e d a f t e r c o l l e c t i o n a n d m e t i c u l o u s l y c l e a n e d f r o m a t t a c h e d s e d i m e n t p a r t i c l e s w i t h i n c a l c a r e o u s e n c ru s t s, u s i n g 4 m o l a r H C l, f o l l o w e d b y t h o r o u g h s i e v i n g i n f r e s h w a t e r. R a n d o m v i s u a l c h e c k s e n s u r e d a l l p a r t s w e r e s e d i m e n t f r e e. S e a g r a s s s a m p l e s w e r e t h e n f r e e z e -d r i e d, s p i k e d w i t h 13 C -l a b e l e d P C D D / F s t a n d a r d, c o n t a i n i n g a l l 1 7 2, 3, 7, 8 -s u b s t i t u t e d P C D D / F s, a n d s o x h l e t e x t r a c t e d f o r 2 4 h o u r s u s i n g h e x a n e : a c e t o n e ( 1 : 1 ). B l u b b e r f r o m d u g o n g s w a s d i g e s t e d u s i n g 4 m o l a r H C l a t 6 0 C f o r t w o h o u r s. Lipid -w a t e r p a r t i t i o n i n g, u s i n g h e x a n e a n d D C M, e x t r a c t e d t h e l i p i d f r a c t i o n. A f t e r g r a v i m e t r i c a l l i p i d d e t e r m i n a t i o n a p p r o x i m a t e l y 2-3 g o f l i p i d w a s s p i k e d w i t h 13 C - l a b e l e d P C D D / F s t a n d a r d. ( N o t e t h a t t h e t i s s u e s a v a i l a b l e f o r f i v e a n i m a l s y i e l d e d l e s s t h a n 1 g o f l i p i d ). I n b r i e f, s a m p l e c l e a n u p f o r b o t h s e a g r a s s a n d l i p i d e x t r a c t s i n c l u d e d a pre -t r e a t m e n t u sing H 2 SO 4 / S i O 2. A n a c i d / b a s e a c t i v a t e d s i l i c a g e l, f o l l o w e d b y d e a c t i v a t e d f l o r i s i l a n d c a r b o n / c e l i t e f r a c t i o n i n g w a s u n d e r t a k e n t o p u r i f y P C D D / F s. T h e f i n a l e l u e n t w a s t r a n s f e r r e d t o v i a l s, c o n c e n t r a t e d t o n e a r d r y n e s s u s i n g a c o n s t a n t 1 N 2 -s t r e a m a n d a k n o w n v o l u m e o f 3 C -l a b e l l e d 1, 2, 3, 4 -T C D D r e c o v e r y s t a n d a r d w a s a d d e d. A n a l y s i s o f t e t r a - t o o c t a -C D D / F s w a s p e r f o r m e d o n a G C ( D B-5 f u s e d s i l i c a c o l u m n, 6 0 m, m m i. d., 0. 1 µm f i l m t h i c k n e s s ) i n t e r f a c e d t o a V G A u t o s p e c h i g h - r e s o l u t i o n m a s s s p e c t r o m e t e r o p e r a t i n g o n a r e s o l u t i o n o f a p p r o x i m a t e l y 1 0, I d e n t i f i c a t i o n o f 2, 3, 7, 8 -s u b s t i t u t e d P C D D / F s a n d Σ P C D D / F s w a s p e r f o r m e d u s i n g r e t e n t i o n t i m e s o f t h e l a b e l l e d s t a n d a r d s a n d i s o t o p e r a t i o s a t M + a n d M or M+4 +. F o r i d e n t i f i c a t i o n o f n o n -lateral s u b s t i t u t e d i s o m e r s, t h e c h r o m a t o g r a m s w e r e c o m p a r e d t o r e f e r e n c e m a t e r i a l s p r o v i d e d b y E R G O SEDIMENT ANALYSIS S e d i m e n t s w e r e a n a l y s e d e i t h e r a t Q u e e n s l a n d H e a l t h S c i e n t i f i c S e r v i c e s ( Q H S S ) l a b o r a t o r i e s i n A u s t r a l i a o r a t E r g o F o r s c h u n g s g e s e l l s c h a f t mb H i n G e r m a n y ( E R G O ). A t Q H S S a m e t h o d w a s u s e d t h a t a l l o w e d t o s c r e e n s a m p l e s f o r O C D D c o n c e n t r a t i o n s. D e t a i l s o f t h i s m e t h o d a r e p u b l i s h e d i n M ü l l e r e t a l. ( a ). I n b r i e f, 5-10 g o f s e d i m e n t w e r e f r e e z e d r i e d, h o m o g e n i s e d w i t h N a 2 SO 4 a n d s p i k e d w i t h 1, 2, 3, 4, 7, 8, 9 - H p C D F a s a n i n t e r n a l s t a n d a r d o f k n o w n q u a n t i t y ( t h i s i s o m e r h a s b e e n d e t e r m i n e d p r e v i o u s l y t o b e p r e s e n t i n c o n c e n t r a t i o n s b e l o w t h e l i m i t o f d e t e c t i o n ( L O D ) i n a l l s e d i m e n t s a m p l e s f r o m Q u e e n s l a n d ( M ü l l e r e t a l a ; b ). S e d i m e n t s w e r e t h e n 9 5
100 C H A P T E R 6 FA T E A N D T R A N S P O R T s o x h l e t e x t r a c t e d f o r 2 4 h o u r s u s i n g t o l u e n e. T h e e x t r a c t w a s c o n c e n t r a t e d a n d s u b j e c t t o c l e a n -u p o n a c i d / b a s e a c t i v a t e d s i l i c a g e l. S e p a r a t i o n o f P C D D / F s f r o m P C B s a n d o t h e r c o -c o n t a m i n a n t s w a s p e r f o r m e d o n a n a l u m i n a c o l u m n ( A l o x B -s u p e r, I C N ). A f t e r c l e a n -u p p r o c e d u r e s, s a m p l e s w e r e c o n c e n t r a t e d t o n e a r d r y n e s s a n d f i l l e d w i t h 2 0 µl o f t o l u e n e c o n t a i n i n g a k n o w n a m o u n t o f d i b u t y l c h l o r i n d a t e, t h e l a t t e r b e i n g u s e d t o a s s e s s t h e p e r f o r m a n c e o f t h e i n s t r u m e n t a n d / o r v o l u m e d i f f e r e n c e s i n t h e v i a l. S a m p l e s w e r e a n a l y s e d o n a G C ( D B 5 ; 3 0 m, m m i. d., µm f i l m t h i c k n e s s ) e q u i p p e d w i t h a n e l e c t r o n c a p t u r e d e t e c t o r. Q u a n t i f i c a t i o n w a s p e r f o r m e d u s i n g a c a l i b r a t i o n o f t h e r e s p o n s e o f t h e i n t e r n a l s t a n d a r d t o O C D D p l u s a c a l i b r a t i o n o f t h e r e l a t i v e r e s p o n s e o f t h e r e c o v e r y s t a n d a r d t o t h e i n t e r n a l s t a n d a r d c o n c e n t r a t i o n. C o n f i r m a t io n o f O C D D w a s c a r r i e d o u t i n s a m p l e s w i t h r e l a t i v e l y h i g h O C D D l e v e l s u s i n g G C -M S, w h e r e t h e M S w a s o p e r a t e d i n m u l t i i o n s c a n. A t E R G O, a n u m b e r o f s e d i m e n t s a m p l e s w e r e a n a l y s e d f o r a l l 2, 3, 7, 8 -s u b s t i t u t e d a n d Σ h o m o l o g u e P C D D / F s u s i n g a c e r t i f i e d m e t h o d ( K l ä r s c h l a m m v e r o r d n u n g ). In b r i e f, 4-8 g o f s e d i m e n t w a s s p i k e d w i t h 13 C -l a b e l l e d P C D D / F s t a n d a r d c o n t a i n i n g a l l 1 7 2, 3, 7, 8 -s u b s t i t u t e d i s o m e r s. S e d i m e n t s w e r e t h e n s o x h l e t e x t r a c t e d f o r 2 0 h o u r s u s i n g t o l u e n e. T h e e x t r a c t s w e r e c o n c e n t r a t e d, s u b j e c t t o a c i d / b a s e c l e a n -u p a n d c o - c o n t a m i n a n t s r e m o v e d o n a n a l u m i n u m o x i d e c o l u m n ( A l u m i n a B-Super, ICN). Some s a m p l e s w e r e f u r t h e r s u b j e c t t o p u r i f i c a t i o n o n a c t i v a t e d c a r b o n. A f t e r c o n c e n t r a t i o n o f 1 t h e e l u e n t t o n e a r d r y n e s s, s a m p l e s w e r e t r a n s f e r r e d t o v i a l s a n d 3 C -l a b e l l e d 1, 2, 3, 4 - T C D D r e c o v e r y s t a n d a r d w a s a d d e d. A n a l y s i s a n d i d e n t i f i c a t i o n o f c o n g e n e r s w a s c a r r i e d o u t a s d e s c r i b e d a b o v e f o r b i o t a QUALITY CONTROL F o r q u a l i t y c o n t r o l b l a n k s w e r e i n c l u d e d w i t h e a c h b a t c h o f 6 t o 1 2 s a m p l e s. T h e r e t e n t i o n t i m e s o f t h e a n a l y t e i n a s a m p l e h a d t o b e w i t h i n 2 s o f t h e r e t e n t io n t i m e s o f t h e i n t e r n a l s t a n d a r d s. T h e i s o t o p e r a t i o s f o r e a c h c o n g e n e r o f t h e M + a n d M i o n s ( f o r t e t r a c h l o r i n a t e d c o n g e n e r s ) a n d t h e M a n d M i o n s ( f o r p e n t a- t o h e p t a c h l o r i n a t e d c o n g e n e r s ) h a d t o b e w i t h i n 2 0 % o f t h e r e s p e c t i v e i n d i v i d u a l v a l u e. T h e l i m i t o f q u a n t i f i c a t i o n i n a g i v e n s a m p l e w a s d e f i n e d b y a s i g n a l t o n o i s e r a t i o g r e a t e r t h a n 3 t i m e s t h e a v e r a g e b a s e l i n e v a r i a t i o n ( d e t e c t i o n l i m i t ) a n d a s u b s t a n c e q u a n t i t y i n t h e s a m p l e g r e a t e r t h a n 3 t i m e s t h e q u a n t i t y i n t h e r e s p e c t i v e b l a n k (q u a n t i f i c a t i o n l i m i t ). V a r i a b i l i t y w a s t e s t e d b y r e p l i c a t e a n a l y s i s o f b l u b b e r a n d 9 6
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