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Central California ASBS Program Annual Report May 13, 2015
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Questions 1. Are there spatial patterns in contaminants or exceedances among reference sites or ASBS discharges? 2. How do exceedances compare to reference values? 3. Are exceedances caused by regulated stormwater discharges? 4. Are there patterns among discharge constituents that could inform choices about management practices?
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Organized by Contaminant 1. Trace metals 2. Polynuclear aromatic hydrocarbons (PAHs) 3. Pesticides – organophosphate pesticides and pyrethroids 4. Bivalve bioaccumulation – chlorinated pesticides, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and acid-positive pharmaceuticals 5. Toxicity – bivalve larval development, urchin fertilization and kelp germination and growth 6. Fecal indicator bacteria (FIBs), nutrients and total suspended solids (TSS)
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Trace Metals 1. North-south gradients and consistent correlations among traces suggest natural effects on trace metal concentrations 2. Concentrations of some trace metals did not different among sample types 3. Pre-storm to storm differences in concentration of only 4 trace metals exhibited significant associations with loads.
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Patterns of Exceedances
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Duxbury Reef: Only 5 of 17 exceedances were not preceded by a pre-storm exceedance (Hg = 1/3) Greater discharge concentrations of As, Ni, Se Pacific Grove: 33 out of 38 exceedances were not preceded by an pre-storm exceedance (Hg = 4/6) Greater discharge concentrations of Cu, Hg, Pb and Zn
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Hg By ASBS Pre-storm samples: Duxbury Reef > Carmel Bay Storm samples: No differences among ASBS Stormwater discharges: No differences among ASBS By Reference Region All regions equal By Sample Type Storm > Reference = Pre-storm = Background
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Sources Trace metals wash off the land during storms They can also be resuspended from bottom sediments during storms
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Sources Trace metals wash off the land during storms They can also be resuspended from bottom sediments during storms
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Metal-Metal Correlations Discharges: Hg-Pb, Hg & Pb-TSS, no Cu or Zn Pre-storm: Hg-Pb, Hg-Cu, Pb-Cu, All 3-TSS, no Zn Storm: Hg-Pb, Hg-Cu, Hg-Zn, Pb-Zn, Pb-Cu, No TSS Background: Hg-Pb, Hg-Zn, Pb-Zn All 3-TSS Hg and Pb travel together, usually with TSS
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Hg versus Pb
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Hg versus Zn
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Hg versus Cu
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Trace Metal Loads 3 methods: Load/storm, Load/acre, Change in receiving water concentration Most of the highest values occurred in Pacific Grove and Carmel Bay Only 4 trace metals had significant correlations between load and changes in receiving water concentration As-, Hg+, Pb+, Zn+ Sediment load reductions = Hg and Pb reductions Source controls = Zn and Cu reductions
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85 th Percentile Compliance What is waste? Many metals exhibited patterns consistent with natural sources. Consideration of pre-storm exceedances? Use- attainability studies may necessary. What if natural sources prevent reductions below 85 th percentile? There were no exceedances of Ocean Plan Instantaneous Maximum.
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PAHs and Pesticides None detected at quantifiable concentrations at references sites
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PAHs and Pesticides None detected at quantifiable concentrations at references sitesAutomatic exceedance for any detection in storm water
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Patterns of Exceedance pyrethroids and organophosphate pesticides were rarely detected PAHs PAHs in 7 samples exceeded Ocean Plan 30-day average objective
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Correlations PAHs and summed Pyrethroids significantly correlated with TSS Load reductions possible through sediment/TSS management
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Compliance Issues No Ocean Plan Instantaneous Maximum for PAHs PAH concentrations measured from grab samples do not accurately reflect actual ocean concentrations No Ocean Plan objectives for pyrethroids or organophosphorous pesticides
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Bioaccumulation Collaboration with CCLEAN 6 sites, including Carmel Bay and Point Reyes Mussels from Carmel River Beach has had among the lowest concentrations of measured organic pollutants over 13 years. Some sites have exceeded human health alert levels, mostly in northern Monterey Bay Acid-positive pharmaceuticals detected at every site, mostly from livestock or pets Caffeine highest concentration detected at The Hook Pollutants trending downward
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Toxicity ASBS samples rarely failed any of four tests Toxicity rarely found at reference sites
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Patterns of Toxicity Several discharge samples and their corresponding receiving water samples from Pacific Grove and Carmel failed the urchin toxicity test during the February 2014 storm
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Toxicity Compliance High Cu and Zn concentrations in the failed discharge and storm samples could be partly responsible Neither Cu nor Zn can be controlled by reducing sediment loads
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Nutrients, TSS and FIBs Rare detection of ammonia and orthophosphate = exceedances for any detection in storm samples Urea was broadly detected, including at reference sites
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Patterns in Nutrients, TSS & FIBs Highest concentrations of all constituents occurred in ASBS storm samples Differences rarely significant by ANOVA but ANOVA insignificance often contradicted by non-parametric test (6/8 significant) ASBS storm concentrations of E. coli linearly associated with discharge concentrations High nutrient concentrations in ASBS storm water could be due to resuspension during storms
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General Considerations Effects of meteorology and logistics During very large storms some reference sites are inaccessible Reduced range in reference values, especially for the storms most likely to have very high runoff Large storm in December 2014 No sampling along Big Sur coast Very high Hg concentrations at 2 northern reference sites If include, Hg 85 th percentile goes from 0.74 ng/L to 2.8 ng/L
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General Considerations Effects of natural processes on trace metal concentrations suggest more work needed before compliance should be enforced Consideration recommended for exceedances in pre- storm samples General consistency between ASBS storm samples and Background samples suggest area wide patterns in nearshore water quality Priority for compliance should be on determining sources of and reductions in toxicity
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