Trends in Polycyclic Aromatic Hydrocarbon Concentrations Sampled in the Tacoma Tideflats. June Justin P. Miller-Schulze

Transcription

1 Trends in Polycyclic Aromatic Hydrocarbon Concentrations Sampled in the Tacoma Tideflats June Justin P. Miller-Schulze

2 Acknowledgements-Thank You! Juliana Bertin: Sampling, extractions, chemical analysis, initial data analysis City of Tacoma Lab Staff: Assistance with GC/MS operation+repairs, etc. Ylena Brusser, Leonora Litzi-Davis, Greg Perez Kris Symer: Cartography Kurt Marx: Weather station assistance Puget Sound Clean Air Agency (PSCAA): PM, Black Carbon data, other assistance Shristi Prakash: Initial method development and data analysis

3 Project Goals Through sampling at the Center for Urban Waters in the Tacoma Tideflats, assess levels of Polycyclic Aromatic Hydrocarbons and their relationship to season, temperature, and air quality parameters measured by the Puget Sound Clean Air Agency (PSCAA) PAHs are interesting as tracers of combustion sources as well as for their effect on toxics loadings to the Puget Sound To do this, we sampled PAHs from CUW roof from ober 2011 to ober 2012

4 For Today I want to talk about the measurements we ve made at the Center for Urban Waters from ober 2011-ober 2012 I ll talk (briefly) about: Why we care about PAHs How we make our measurements What we found for a few selected PAHs How these data relate to some other air quality parameters, and the connection between PAH emissions in air and water quality

5 PAHs and Combustion Sources PAHs are classified as 2 or more aromatic rings fused together: Napthalene PAHs are present in petroleum-based fuels (crude oil, gasoline, diesel, etc.) and the emissions of carbon-based fuels (gasoline, diesel, biomass/wood, etc.) Different fuels contain different PAHs, both before combustion (petrogenic, i.e., oil spills) and after combustion (pyrogenic, i.e., smokestack emissions)

6 PAHs A link between PAHs and cancer has been speculated since the late 1700s, when Sir Percival Pott observed a high incidence of skin cancer in chimney sweeps Fluoranthene Pyrene eep.png

7 PAHs Polycyclic Aromatic Hydrocarbons (PAHs) are one of the toxicologically relevant chemicals in particulate matter and air pollution in general One of the mechanisms of PAH toxicity is to induce mutations in DNA, leading to cancer CANCER Perera, F.P., Environment and Cancer: Who Are Susceptible?, Science 278, 1068 (1997); DOI: /science

8 PAH Deposition and Environmental Fate+Transport PAHs can have between 2 and 8+ aromatic rings The more rings, the greater the number of carbons, the higher the boiling point (and the less volatile) The vast majority (~95%) of PAH deposition occurs via dry particle deposition and wet deposition processes Recent reports by the Washington State Department of Ecology indicate that direct deposition of PAHs to Puget Sound is a relatively minor source (as compared with stormwater runoff) Brandenberger, J.M., P. Louchouarn, L-J Kuo, E.A. Crecelius, V. Cullinan, G.A. Gill, C. Garland, J. Williamson, and R. Dhammapala, 2010, Control of Toxic Chemicals in Puget Sound, Phase 3: Study of Atmospheric Deposition of Air Toxics to the Surface of Puget Sound, WA Dept of Ecology, Publication no ,

9 So, we want to measure PAHs because: They can be used as tracers of combustion sources of particulate matter in the region, and the region has a problem with particulate matter They are toxicologically relevant in and of themselves They represent a small but significant source of the PAHs in the sediments of Puget Sound (in terms of direct atmospheric deposition)

10 Sampling of PAHs PAHs are semi-volatile- meaning that they exist both in the gas phase and condensed (particulate) phase and Because of this, PAHs are found in 2 phases in air, and we collect them in different ways depending on the phase For gas-phase samples, we collect them on a polyurethane foam cartridge (like a foam mattress) that we pull air through For particulate-phase samples, we collect them on a filter that we pull air through

11 Sampling TISCH Corp Hi-Vol Air Sampler located on roof of Center for Urban Waters Approximate height of sampler = 16.8 m above sea level Sampling done on EPA s 1-in-6 day sampling schedule Flow rate = ~180 L/min Samples collected are 24-hour integrated samples Total volume sampled= ~ 275 m 3

12 Measurements In our laboratory, we extracted and analyzed these collected samples for a suite of 26 PAHs and 6 phthalate esters Each sample (each day) is really 2 samples : 1 particulate and 1 gas-phase sample We did not analyze these samples for mass or any other air quality parameters The Puget Sound Clean Air Agency has monitoring locations at 2 nearby locations: Tacoma Tideflats (on the opposite side of the tideflats from CUW) South L street (close to Lake Wapato)

13 Instrumental Response Sample Preparation (Abbreviated) Collect Sample Extract Sample with 700 ml organic solvent Concentrate Extracted Sample from 700 ml 1 ml Analyze sample for PAHs by Gas Chromatography Mass Spectrometry (GC-MS) Concentration

14 Sounds like a lot of work and it is! But it s necessary: Because the concentrations of these PAHs in ambient air can be <0.01 ng/m 3 We extract the PAHs from the particulate or gas-phase samples with 700 ml of organic solvent-if we get 100% of the PAHs into this volume, we ve got a concentration of ~1 ng/l (or 1 part per trillion) in our final extracts (too low for our instrumentation) Volume = 700 ml So, in order to see the levels present in ambient air, we need this 1000-fold concentration factor Volume = 1 ml

15 PSCAA Data Data collected at South L and Tacoma Tideflats PSCAA monitoring sites during our study period and obtained from PSCAA s cool air graphing tool :

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17 Relationship between PM and Temperature Occurrences of PM 2.5 > 35 µg/m 3 are confined to the months between November- February Because of the meteorology in the region, particulate matter levels tend to be higher when the temperatures are lower 24-Hour Integrated Concentration ( g/m 3 24-Hour Integrated Concentration ( g/m 3 ), Temperarture (C o ) ) South L St. Monitor Fine Particulate Matter (PM South St. Monitor Fine Particulate Matter (PM 2.5 ) 2.5 Sep Sep Nov Nov Dec Dec Jan Jan Feb Feb Mar Mar Apr Apr May May Jun Jun Jul Jul PM2.5 South L Avg Temp Aug Aug Sep Sep Nov Nov

18 PAH Data Some PAHs are relatively volatile-so as the ambient temperature increases, these PAHs are almost exclusively present in the gas-phase Some PAHs are relatively non-volatile-so they are primarily found in the particulate phase I ll be talking about 3 types of PAHs in the next few slides: Light PAHs-Found mostly in gas phase Medium PAHs-Found in both phases Heavy PAHs-Found mostly in particulate phase

19 Phenanthrene, Anthracene Concentrations ober 2011-ober 2012 Concentrations dominated by gas phase Concentration (ng/m 3 ) Phenanthrene Gas Phase Particulate Phase Phenanthrene concentrations exceed Anthracene concentrations by ~factor of 10 Less Anthracene in warmer months Concentration (ng/m 3 ) Anthracene Nov Dec Jan Feb Mar Nov Apr Dec May Jan Jun Feb Jul Mar Aug Sep Apr May Jun Jul Aug Sep Gas Phase Particulate Phase 0.0

20 1.2 Phen/(Phen+Anthr) Ratio Trends Line = 0.7 Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Phen/(Phen+Anthr) Ratio Value Values >0.7 speculated to indicate emissions from lubricants or fossil fuels, values below indicate biomass combustion Relatively high values for ratio could be due to proximal sources M. del Rosario Sienra et al. / Atmospheric Research 75 (2005)

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22 The Center for Urban Waters is located in this circle (this is an old picture)

23 Fluoranthene and Pyrene: Medium Weight PAHs More distribution between gas and particulate phase as compared with lighter PAHs Concentration (ng/m 3 ) Fluoranthene Gas Phase Particulate Phase Elevated levels in the colder months as compared with warmer months Concentration (ng/m 3 ) 0 Pyrene Nov Dec Jan Feb Nov Mar Dec Apr Jan May Feb Jun Mar Jul Apr Aug Sep May Jun Jul Aug Sep Gas Phase Particulate Phase 0

24 Concentration (ng/m 3 ) Heavy PAHs: Benz(a)Anthracene Indeno (123 cd) Pyrene Benzo (ghi) Perylene Little to no heavy PAHs found in gas phase High(er) detection limits for heavy PAHs (partially due to low sensitivity) Heavy PAHs only detected in colder months Benzo (ghi) Perylene Gas Phase Particulate Phase Limit of Detection Concentration (ng/m 3 ) Concentration (ng/m 3 ) Benz(a)Anthracene Indeno (1,2,3 cd) Pyrene Nov Dec Jan Feb Mar Apr May Jun Gas Phase Particulate Phase Limit of Detection Jul Aug Sep Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Gas Phase Particulate Phase Limit of Detection

25 Retene Formation Pathway Retene is formed from the thermal degradation of abietic acid Abietic acid is a resin found in coniferous trees Retene is a good marker for the combustion of coniferous wood combustion

26 Retene (Marker of of Woodsmoke Combustion) Gas-Phase Gas-Phase Particulate Particulate Phase Phase40 Nov Concentration (ng/m 3 ) Dec Jan Feb Feb Mar Mar Apr Apr May May Jun Jun Jul Aug Jul Sep Aug Sep South L PM PM 2.5 Concentration ( g/m 3 ) -20 0

27 South L PM 2.5 Concentration ( g/m 3 ) Relationship Between South L PM and Retene Heating Season (ober 1-March 30) Non-Heating Season (April 1-September 30) Retene Concentration (ng/m 3 )

28 Initial Summary/Conclusions Clear relationship between PAH size (and volatility) and detection frequency and distribution between phases Gas phase concentrations dominate total concentrations, for light and medium PAHs Particulate phase concentrations dominate heavy PAHs Retene concentrations reflect knowledge about relevant PAH sources

29 Properties of PAHs Translate Into Complex Distribution Issues

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31 Wrap Up So, PAHs are a class of compounds that are alike chemically but span a range of physical properties (volatility, sorption efficiency, etc.) This comes up in sampling air for PAHs, in a (relatively) simple way: they exist in the gas phase and particulate phas In the watershed-scale environment, though, this means that: Different PAHs will be distributed to a different extent throughout air, water, sediment, biota, etc. This distribution will have some temporal component (PAHs emitted years ago may still be released from sediments currently) This is a tough problem

32 Emerging Contaminants as Tracers of Water Quality Parameters Currently, a collaborative project between UW- Tacoma/Center for Urban Waters and the Kitsap County Department of Public Health (funded by the Russell Family Foundation) aims to evaluate the utility of employing tracers of septic Kitsap tank County effluent to determine (roughly) sources of bacterial pollution Fraction Detected Kitsap County Tracer Study: Batch 1 Fraction Detected: All Sites, Confirmed Septic Only Use a Suite of Emerging Contaminants to assess Human All Sites Impacts on Water Confirmed Septic Quality Impact Stimulants: Caffeine Pharmaceuticals: Acetaminophen, ibuprofen, carbamazepine Metabolites: Paraxanthine (caffeine), cotinine (nicotine) Herbicides: Atrazine, mecoprop Acetaminophen Atrazine Benzylparaben Caffeine Trans-Cinnamic Acid Carbamazepine Cotinine Ethyl Vanillin Ibuprofen Mecoprop Nicotine Paraxanthine Ensulizole Propylparaben Ractopamine Sulfadimethoxine Sulfamethoxazole Sulfamethazine Sucralose Vanillin Misc. Food+Drug: Nicotine, Vanillin, Sucralose

33 Thanks for Your Time-Questions? (If you think of something on the way home):