Der Ausblick von der Flussmündung Hinauf zu den Bergen Herr Doctor Khalil E. Abu-Saba

The View from Downstream Khalil Abu-Saba San Francisco Bay Regional Water Quality Control Board Manage in the watersheds. Measure in the water.

Overview What chromium and silica taught us The mercury story in California Connecting downstream data to upstream watersheds:

The usual caveats... This discussion is about: Published historic accounts Public information (hearings, staff reports, peer-reviewed science) Staff recommended actions This discussion is not about: The will or intent of the Regional Board, the State Board, or the State of California The anticipated outcome of any public process

Hydrology + Geography = Geochemistry

Summer: Low FlowWinter: High Flow Chromium Silica Flow Details in Abu-Saba and Flegal (1997)

First Point: The View from Downstream Chromium and Silica are geochemical tracers We can see the effect of shifting freshwater sources downstream Winter 1993 pulses of waters entered estuary Chromium / Aluminum ratios also showed a shifting sediment source in Winter 1993

Second Point: The View from Downstream The story of mercury in California is recorded in the sediments Sand Clay Mercury in Sediment Current Background Sources Historic Baseline

RMP Base Program Data % Fines (<63 µm) Clay Sand Mercury (ppm)

Design Integration Workgroup Current Background % Fines (<63 µm) Clay Sand Mercury (ppm)

State TMDL funds to evaluate Pre-human condition of Lower South Bay Current = 0.40 Baseline = % Fines (<63 µm) Clay Sand Mercury (ppm)

Guadalupe River Mercury TMDL Spearheaded by SCVWD New Almaden % Fines (<63 µm) Clay Sand Mercury (ppm)

RMP Air Deposition Study and relevance to contemporary background 0.34 ppm ? ? Mining Air Dep. Regional Global % Fines (<63 µm) Clay Sand Mercury (ppm)

% Fines (<63 µm) Mercury in Bottom Sediments (µg/g) Clay Sand Investigation of remote watershed sources: Winter 1993 CALFED CVRWQCB UCSC

15 Bacteria in wetlands, mudflats and sloughs Total Mercury Methylmercury MethylationBioaccumulation Mercury is methylated in the margins of the Bay Methylation rates highest at the fresh-salt interfaces High total mercury concentrations ALWAYS associated with high methylmercury concentrations High methylmercury concentrations OFTEN, but NOT ALWAYS associated with high total mercury concentrations Link to Beneficial Uses: Methylmercury studies by CALFED, BASMAA, SCVWD, UCSC

Basin Plan Narrative Objective for Bioaccumulation Controllable water quality factors shall not cause a detrimental increase in the concentrations of toxic substances found in bottom sediments or aquatic life. Effects on aquatic organisms, wildlife, and human health will be considered.

Third Point: The View from Downstream RMP Base Program sets the stage Pilot, special, and external studies address key uncertainties Todays talk: –SFEI, State, CALFED, BASMAA, SCVWD, CVRWQCB, UCSC…. Many many others –POTW ultra-clean monitoring, near-field methylmercury measurements, SFEI consumption study, RMP fish surveys... Keep those cards and letters coming!

+ + But What Does it All Mean?