Der Ausblick von der Flussmündung Hinauf zu den Bergen Herr Doctor Khalil E. Abu-Saba
The View from DownstreamKhalil Abu-Saba San Francisco Bay Regional Water Quality Control Board Manage in the watersheds. Measure in the water.
Overview Connecting downstream data to upstream watersheds: • What chromium and silica taught us • The mercury story in California
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 The usual caveats...
Hydrology + Geography = Geochemistry
Summer: Low Flow Winter: 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
Sources Current Background Mercury in Sediment Historic Baseline Sand Clay Second Point: The View from Downstream • The story of mercury in California is recorded in the sediments
1.2 0.8 Mercury (ppm) 0.4 0.0 0 50 100 % Fines (<63 µm) Clay Sand RMP Base Program Data
1.2 0.8 Mercury (ppm) 0.4 0.0 0 50 100 % Fines (<63 µm) Clay Sand Design Integration Workgroup Current Background
1.2 0.8 Mercury (ppm) 0.4 0.0 0 50 100 % Fines (<63 µm) Clay Sand State TMDL funds to evaluate Pre-human condition of Lower South Bay Current = 0.40 Baseline = 0.06
1.2 0.8 Mercury (ppm) 0.4 0.0 0 50 100 % Fines (<63 µm) Clay Sand Guadalupe River Mercury TMDL Spearheaded by SCVWD New Almaden
1.2 0.8 Mercury (ppm) 0.4 0.0 0 50 100 % Fines (<63 µm) Clay Sand RMP Air Deposition Study and relevance to contemporary background Global Regional Air Dep. ? 0.34 ppm ? Mining
Investigation of remote watershed sources: CALFED CVRWQCB UCSC 1.2 Mercury in 0.8 Bottom Winter 1993 Sediments (µg/g) 0.4 0.0 0 50 100 % Fines (<63 µm) Clay Sand
Link to Beneficial Uses: Methylmercury studies by CALFED, BASMAA, SCVWD, UCSC Methylation Bioaccumulation Total Mercury Bacteria in wetlands, mudflats and sloughs Methylmercury • 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
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 • Today’s 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?