Post on 24-Dec-2015
transcript
Central CaliforniaASBS Program
Annual ReportMay 13, 2015
Questions1. 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?
Organized by Contaminant1. 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)
Trace Metals1. 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.
Patterns of Exceedances
Patterns of Exceedances
Patterns of ExceedancesDuxbury 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
HgBy 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
SourcesTrace metals wash off the land during storms
They can also be resuspended from bottom sediments during storms
SourcesTrace metals wash off the land during storms
They can also be resuspended from bottom sediments during storms
Metal-Metal CorrelationsDischarges: 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
Hg versus Pb
Hg versus Zn
Hg versus Cu
Trace Metal Loads3 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 concentrationAs-, Hg+, Pb+, Zn+
Sediment load reductions = Hg and Pb reductions
Source controls = Zn and Cu reductions
85th Percentile ComplianceWhat 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 85th percentile? There were no exceedances of Ocean Plan Instantaneous Maximum.
PAHs and PesticidesNone detected at quantifiable concentrations at
references sites
PAHs and PesticidesNone detected at quantifiable concentrations at
references sites Automatic exceedance for any detection in storm water
Patterns of Exceedance
pyrethroids and organophosphate pesticides were rarely detected
PAHs
PAHs in 7 samples exceeded Ocean Plan 30-day average objective
CorrelationsPAHs and summed Pyrethroids significantly
correlated with TSSLoad reductions possible through
sediment/TSS management
Compliance IssuesNo 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
BioaccumulationCollaboration 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 petsCaffeine highest concentration detected at The
Hook
Pollutants trending downward
ToxicityASBS samples rarely failed any of four tests
Toxicity rarely found at reference sites
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
Toxicity ComplianceHigh 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
Nutrients, TSS and FIBsRare detection of ammonia and orthophosphate
= exceedances for any detection in storm samples
Urea was broadly detected, including at reference sites
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
General ConsiderationsEffects 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 2014No sampling along Big Sur coastVery high Hg concentrations at 2 northern reference
sitesIf include, Hg 85th percentile goes from 0.74 ng/L to
2.8 ng/L
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