Cache Creek Settling Basin Mercury Studies

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1 Cache Creek Settling Basin Mercury Studies Charlie Alpers 1 and Josh Ackerman 2 1 USGS California Water Science Center, Sacramento, CA 2 USGS Western Ecological Research Center, Davis, CA

2 Outline of Presentation Background Goals and objectives Approach Preliminary results (Phase 1: ) Plans for future work (Phase 2: )

3 Collaboration and Cooperation Jacob Fleck (USGS CAWSC) Liz Beaulieu (USGS CAWSC) Mark Marvin-DiPasquale (USGS BRR) Lisa Windham-Myers (USGS BRR) Craig Stricker (USGS FORT) Sacramento Field Office (USGS CAWSC) Fred Gius, John Nosacka (DWR) Lev Kavvas and others (UC Davis)

4 Goals Provide DWR and other stakeholders with data and interpretive reports on Hg and MeHg needed for future management of the CCSB Meet specific data requirements TMDLs (Cache Creek and Delta) (RWQCB, 2005, 2010) Anticipate future data needs Operation and Maintenance Manual (USACE, 2007)

Sacramento River Clear Lake Cache Creek Cache Creek Settling Basin Mercury Contamination from Historical Mining Hg-contaminated sediment from Hg mines (Coast Range) and Au mines

5 Sacramento River Clear Lake Cache Creek Cache Creek Settling Basin Mercury Contamination from Historical Mining Hg-contaminated sediment from Hg mines (Coast Range) and Au mines (Sierra Nevada) Coast Ranges Central Valley Cache Creek watershed one of the most Hg-contaminated Downstream effects of MeHg in San Francisco Bay and Delta USGS Fact Sheet

6 California Mercury Production More than 100 million kg of Hg produced from 239 mines About 35 million kg lost to atmosphere from furnaces A flask contained 34.8 kg (76.5 lbs) prior to 1904, and 34.1 kg (75 lbs) afterwards (Churchill, 2000)

7 Background (1 of 2) Cache Creek Hg hot spot Up to 30% of Hg load of the entire Sacramento R. watershed* Source of ~60% of Hg load into Yolo Bypass* Only ~ 2% of the discharge of the Sacramento R. watershed* Multiple Hg sources Active hot springs: Clear Lake / Sulphur Creek Fossil hot springs: hydrothermal alteration, Hg deposits Active cold springs: saline waters with high Hg, DOC Hg mine wastes: calcines, waste rock Several Hg mine sites with recent / ongoing remediation Sulphur Bank Mine (Superfund site) Abbott / Turkey Run Mines Rathburn / Petray Mines *Wood et al., 2010, Delta TMDL report

9 Rathburn and Petray mines Cache Creek watershed adapted from: Domagalski et al. (2004)

10 From: Domagalski et al. (2004) USGS WRIR

11 Inflow January 22, 2010 Discharge: ~3,000 ft 3 /s ~85,000 L/s Outflow - gate Outflow - weir

12 Background (2 of 2) Cache Creek Settling Basin (CCSB) a sediment trap Built by U.S. ACE in 1937, modified in 1993 Keeps sediment out of Yolo Bypass Protects City of Sacramento from flooding Interest in Hg trapping efficiency of CCSB Currently traps ~50% (to 70%) of sediment and p-hg load Future TMDL goal: 75% trapping efficiency Concerns about methylmercury CCSB may be a source of MeHg Sensitive downstream areas: Yolo Bypass, SF Bay-Delta

13 2009 Data from CropScape (USDA) Orthophoto from NAIP (2009) : 51% crops, 49% riparian

14 Overall Study Objectives Phase I ( ) Primary: In vs. out Determine [THg] & [MeHg] in water at CCSB inlet/outlet: storm and non-storm flow conditions Compute THg and MeHg loads in/out of CCSB Secondary: In-basin processes Assess spatial/temporal variability of [THg] & [MeHg] in water & sediment within the CCSB Assess vertical variability in sediment [THg] in deep cores Identify high [THg] layers

15 Water and Sediment Sampling Phase I [Note: sampling locations are approximate not all proposed stations were sampled] Water sampling WY2010: Dec June 2010 WY2011: Dec 2010 June 2011 WY2012: Oct April 2012 Sediment sampling May 2010 Sept Feb May 2011 Oct March 2012

16 Water-quality sampling Three sampling locations: Cache Rd. 102, CCSB Outlet & CCSB Spillway (weir) Baseline sampling at 3-wk intervals during wet season Storm event sampling: 8-10 samples per year (rising, peak, falling) Parameters: THg, filtered and unfiltered (or filtered and particulate) MeHg, filtered and unfiltered (or filtered and particulate) RHg(II), particulate Suspended sediment concentration (SSC) w/sand breakdoc & optical properties Field parameters (T, SC, ph, DO, turbidity) *Anions *Chlorophyll-a & pheophytin-a * baseline samples only

17 Water sampling at a range of flow conditions 12,000 10,000 WY2010 WY samples 2011 samples CCSB inflow 8,000 avg Q (cfs) 6,000 4,000 2, Dec 29-Dec 26-Jan 23-Feb 23-Mar 20-Apr 18-May 15-Jun PRELIMINARY DATA SUBJECT TO REVISION

18 PRELIMINARY DATA SUBJECT TO REVISION

19 Slide(s) with unpublished data not yet available for public distribution

Water and Sediment Sampling Phase I [Note: sampling locations are approximate not all proposed stations were sampled] Water sampling WY2010: Dec.

20 Water and Sediment Sampling Phase I [Note: sampling locations are approximate not all proposed stations were sampled] Water sampling WY2010: Dec June 2010 WY2011: Dec 2010 June 2011 WY2012: Oct April 2012 Sediment sampling May 2010 Sept Feb May 2011 Oct March 2012

21 Sediment sampling locations within CCSB ( )

22 Slide(s) with unpublished data not yet available for public distribution

23 Deep sediment sampling (augering) 10 locations drilled in additional locations drilled in 2012 Most holes to 30 feet (9 m) One hole to 47 feet (14 m) Analysis of THg, MeHg, RHg(II) and GSD 8-inch composites at 1, 3, 5, 15 and 25 ft depths Deposition rate dating using 137 Cs Preliminary results (pending)

24 CCSB Drilling sites Red 2011 (10 locations) Yellow 2012 (5 locations)

27 Slide(s) with unpublished data not yet available for public distribution

28 Plan to raise weir by 6 ft at Year 25 (2018) Source: (USACE, 1997) Yrs 25-35: 3 ft / 10 yrs = 3.6 in/yr (~ 9 cm/yr) Yrs 5-25: 2 ft / 20 yrs = 1.2 in/yr (~ 3 cm/yr)

29 Preliminary Conclusions (Phase 1) See Alpers et al. (2011) Abstract, ICMGP Cache Creek Settling Basin Inflow vs. Outflows: During flow across CCSB: Decrease in concentration of SS, p-thg Increase in concentration of MeHg, f-thg, and DOC Esp. during lower-flow periods between storms Spatial variations in ag vs. non-ag land use: In riparian (non-ag) areas: Higher sediment MeHg/THg Higher LOI, TRS & Fe(II) consistent with Hg-methylation Management challenge: balancing THg load reduction with possible increase in MeHg production and export

30 Future work planned Phase 2 ( ) Continue with water sampling at inlet and outlets Compute Hg and MeHg loads for 5 years (WY ) More comprehensive analysis of spatial and seasonal variations of MeHg within CCSB Biological sampling birds and fish Sediment and overlying water at ~40 locations to be sampled quarterly (4x/yr; 2 wet, 2 dry) for 2 years

31 Biological sampling Goal: Investigate spatial gradients in MeHg within the CCSB Approach: Bird sampling: Eggs from nests in bird boxes ( ) Blood from birds trapped in mist nets ( ) Fish sampling: Caged mosquitofish, deployed at several locations along flow path (2013)

35 Egg samples: N = 4 species, N = 60 eggs Tree swallow (10) House wren (44) Ash-throated flycatcher (3) Mourning dove (3) House wren Josh Ackerman, unpublished data

Blood samples N = 40 species, N = 483 birds Frugivore Granivore Insectivore Omnivore Vermivore House finch (31) Mourning dove (1) Barn swallow (1) American goldfinch (60) American robin (23) Lesser

36 Blood samples N = 40 species, N = 483 birds Frugivore Granivore Insectivore Omnivore Vermivore House finch (31) Mourning dove (1) Barn swallow (1) American goldfinch (60) American robin (23) Lesser goldfinch (8) Willow flycatcher (1) Bullock's oriole (8) Pacific slope flycatcher (1) Brown-headed cowbird (25) Black pheobe (12) Blue grosbeak (10) Wilson's warbler (1) California towhee (21) Golden-crowned sparrow Josh Ackerman, unpublished data Downy woodpecker (6) Fox sparrow (1) Nuttall's woodpecker (2) Golden-crowned sparrow (13) Marsh wren (1) Lark sparrow (8) Bewick's wren (16) Lincoln's sparrow (11) Brewer's blackbird (2) Oregon junco (1) Ash-throated flycatcher (6) Savannah sparrow (1) Tree swallow (23) Spotted towhee (13) Hermit thrush (5) White-crowned sparrow (14) Audubon's warbler (3) Song sparrow (66) House wren (35) Lazuli bunting (7) Common yellowthroat (18) Black-headed grosbeak (14) Yellow-breasted chat (1) Bushtit (6) Orange-crowned warbler (5) Yellow warbler (2)

37 Tree swallows Barn swallow

38 Hg analysis of bird eggs and blood samples Not all samples collected will be analyzed Samples will be selected for analysis based on spatial distribution and species Preliminary analyses expected in early 2013 Additional sampling planned Collection in spring and summer 2013 Analysis by late 2013 or early 2014

39 Planned water and sediment sampling Phase 2 Seasonal sampling planned (4x/yr, 2 wet, 2 dry) for 2 years ~ 40 sampling sites in 4 zones Sites selected to correspond with biota sampling locations

Proposed Hg methylation tests 3 environments: a) current deposition area b) planned notches in training levee (N1, N2) [Note: locations approximate] c) corn fields in NE corner In each environment: -

40 Proposed Hg methylation tests 3 environments: a) current deposition area b) planned notches in training levee (N1, N2) [Note: locations approximate] c) corn fields in NE corner In each environment: - determine methylation potential of sediment (spike with 199 HgCl 2 ) - perform mixing experiments using suspended sediment in inflow water as spike [similar approach as Marvin- DiPasquale et al. (2011) USGS SIR B]

41 Planned reports DWR Reports to RWQCB 2015 and 2018 Primary Objective: In vs. out Determine [THg] & [MeHg] in water at CCSB inlet/outlet: Compute THg and MeHg loads in/out of CCSB Journal articles: THg, MeHg, SS loads 2013, 2015 Secondary Objective: In-basin processes Assess spatial/temporal variability of [THg] & [MeHg] in water, sediment, and biota within the CCSB Journal articles: In-basin variability 2015 Assess vertical variability in sediment [THg] in deep cores USGS report: 2013 Journal article: 2015 Assess Hg methlyation potential associated with various management scenarios (e.g. weir notching, extending flow path to north) Journal article: 2015

Mercury and methylmercury transport in the Cache Creek Settling Basin, California, U.S.A.

Mercury and methylmercury transport in the Cache Creek Settling Basin, California, U.S.A. Alpers, C.N. 1, Fleck, J.A. 1, Marvin- DiPasquale, M. 2, Beaulieu, E. 1, and Wright, S.A. 1 1 U.S. Geological Survey,