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Concentrations and loads of PCBs and OC pesticides in the urbanized Guadalupe River watershed Presented to: RMP Sources, Pathways, and Loadings Workgroup.

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Presentation on theme: "Concentrations and loads of PCBs and OC pesticides in the urbanized Guadalupe River watershed Presented to: RMP Sources, Pathways, and Loadings Workgroup."— Presentation transcript:

1 Concentrations and loads of PCBs and OC pesticides in the urbanized Guadalupe River watershed Presented to: RMP Sources, Pathways, and Loadings Workgroup May 22, 2007 Jon Leatherbarrow San Francisco Estuary Institute, Oakland, CA UC Davis, Civil & Environmental Engineering, Davis, CA Item #2

2 PCB and OCP use in urban areas Chemical Initial Uses Restrictions in the 1970s Continued or Recent Urban Use PCBs( ) Electrical and industrial uses; consumer products 1979: ban on production and use Continued enclosed applications; DDT( ) Agriculture, mosquito, pest control for res/com/forest 1973: ban, except emergency uses; still used outside of U.S. No significant use Chlordane( s) Agriculture, lawns, gardens; termites 1978: ban on use for food and above ground appl. Post-1983: sub-surface structural termite cont.; cancelled 1988 Dieldrin( ) Agriculture, soils, wood preservative, moth- proofing, termites 1970s: ban on use for food and above ground appl. Post-1974: sub-surface structural termite cont.; cancelled 1987 HCHs (1940s- Present) Agriculture, garden, farms, xmas trees, etc. 1976: ban on production and use of technical-HCH Post-1977: lindane ( - HCH) use for seed treatment & ornamentals Item #2

3 Areas of heaviest use of PCBs; contaminated areas; continued use and accidental release; Areas of most recent widespread use of many OCPs (e.g., chlordane, dieldrin, HCHs); direct application, release Development and disturbance of former agricultural lands; post World War II and Silicon Valley boom in the 1960s Persistence in watershed soils and aquatic sediments due to chemical and physical stability; Continuing local, regional, and global impacts from cycling of contaminant residues through non-point source pollution pathways (i.e., runoff, atmospheric) Legacy contamination in urban environment Item #2

4 Sample collection: PCBs(n=72, WY ) OCPs: DDT, HCHs(n=44WY ) dieldrin, chlordane Grab samples (WY2003) D-96 sampler (WY ) Sample analysis Laboratory: Axys Analytical Services, Ltd. Sidney, BC Method: HRGC/HRMS, EPA 1668A Guadalupe River monitoring approach Item #2

5 Guadalupe River monitoring results ParameternFWMC(ng/L)Range(ng/L)Composition 40 PCBs 40 PCBs – Cls (88 ± 6%) 5-Cls (88 ± 6%) 6 DDT 6 DDT – 71 p,p-DDE (40 ± 6%) p,p-DDT (28 ± 7%) p,p-DDD (20 ± 8%) 7 Chlordane 7 Chlordane – 64 -chlor (29 ± 2%) -chlor (29 ± 2%) -chlor (28 ± 2%) -chlor (28 ± 2%) t-non (20 ± 8%) Dieldrin – HCHs 4 HCHs – 1.3 -HCH (49 ± 10%) -HCH (49 ± 10%) -HCH (25 ± 9%) -HCH (25 ± 9%) -HCH (20 ± 8%) -HCH (20 ± 8%) Item #2

6 Regression: contaminants on SSC Rising stage Δ Falling stageBase flow Item #2

7 Annual loading (***preliminary***) Load in Grams/Yr WY 2003 WY 2004 WY 2005 WY 2006 AVG (± STDEV) PCBs PCBs , (± 330) DDT DDT , (± 300) Chlor Chlor (± 210) Dieldrin (± 28) Top 7 days (%) 62-70%67-74%42-47%35-42% Item #2

8 Watershed yields: Penta-PCBs Estimates from Fikslin and Suk (2003); Foster et al. (2000a,b); Ko and Baker (2004); Leatherbarrow et al. (2005) Item #2

9 Watershed yields: Penta-PCBs Rowe et al. (2007) estimate that highlighted watershed yields reported in Delaware River TMDL are atmospherically driven Item #2

10 Watershed yields*: Pesticides Sum of chlordane compounds Dieldrin Sum of p,p-isomers of DDE, DDD, DDT *All yields in ng/m2/day; Estimates from Foster et al. (2000); Foster et al. (2003); Leatherbarrow et al. (2005) Item #2

11 Potential sources: PCB congeners 12/16/02 19:55 (GR24) 10/26/04 5:50 (GR310) 10/26/04 7:50 (GR311) Aroclor 1260 Aroclor 1254 Item #2

12 Potential sources: PCB congeners Aroclor 1016 Aroclor 1242 Ratio of GR311:GR310 Item #2

13 Watershed processing of PCBs Penta-PCBs Hepta-PCBs Item #2

14 Watershed processing of DDT p,p-DDT p,p-DDD Item #2

15 Diffuse source distribution in the watershed: Positive linear relationships of contaminants with SSC; Relatively constant PCB congener profile; Gradient in contamination from urban to non-urban areas: Differences in rising and falling stage regressions indicates high SSC-based concentrations likely emanating from lower urban areas compared to upper non-urban areas; Periodic inputs of PCBs from unique sources: Anomalous profiles in some samples; Atmospheric inputs likely discernable in evolving profile patterns; Relatively unweathered sources of pesticides: High percentage of parent DDT material at high flows; Similar increase in technical mixture profiles in other OCPs; Implications of findings: sources Item #2

16 Watershed yields consistent with contaminated urban areas : PCB yields above expected yields from atmospheric deposition; Urban influence evident compared to other land uses : Comparison of watershed yields indicates high potential source density in urban areas compared to non-urban areas; Urban runoff contributes to impairment of SF Bay : Mass budget models indicate loading of PCBs and OCPs on the order of 10 kg/yr could significantly delay water quality improvement; PCB TMDL loading target for urban runoff = 2 kg/yr Loads of kg/yr from Guadalupe, combined with other tributaries, are expected to contribute to prolonged impairment of water quality. Implications of findings: loadings Item #2

17 Modeling Hydrologic routing: where is the water coming from? Sediment transport: where is the sediment coming from? Contaminant transport: link evolving contaminant profiles to sources of water and sediment. Treatment options Source reconnaissance Structural treatment device placement and optimization Information gathering on other tributaries Monitoring other selected tributaries Extrapolation/modeling methods Information needs Item #2

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