1. Hyojin Kim May 9 th 2008 California Water Symposium

2.  Mercury Total Daily Maximum Load (TMDL)  Sources of Mercury  Historic mine activities (70%)  Bed Erosion  Central Valley Watershed  Urban Stromwater (14%)  Methylmercury  Toxicity  bioavailability  Bioaccumulation (http://www.ec.gc.ca/MERCURY/EN/bf.cfm)

3.  Mercury Methylation  Mainly biotic processes  Environmental factors  Microbiology  Temperature  pH  Organic matters  Redox conditions  Sulfide  Salinity

4.  To identify water quality indicators associated with mercury methylation  To assess the relationship between land use and methylmercury

6.  Water and Sediment Monitoring data  Regional Monitoring Program  Land use  EPA  Correlation Coefficient Analysis  EXCEL 2007 Data Analysis Toolbox

7.  Water and Sediment Monitoring data  2000. 07 ~ 2006. 08  High concentrations of Heavy Metals

8.  San Francisco Bay area  Agricultural Land use (34%)  Forest (35%)  Residential type (9%)

10.  Land Use vs Methylmercury  Agricultural land use types  Strong negative correlation  Developed land use types  Strong positive correlation  Land Use vs Mercury  Strip mines  Positive correlation

11.  Water Quality Indicators vs Methylmercury  Developed Regions  Coyote Watershed  San Francisco Bay Watershed  San Pablo Watershed  No significant correlation

12.  Water Quality Indicators vs Methylmercury  Undeveloped Regions  Lower Sacramento Watershed  San Joaquin Delta Watershed  Suisun Bay Watershed  Significant correlation ( > ±0.5)  Heavy metals  Solid phase  Temperature  Total Nitrogen  Total Organic Carbon

13.  Water Quality Indicators vs Mercury  Positive correlation to Ag  Lower Sacramento (0.959) / San Francisco Bay (0.494) / Suisun Bay (0.469) / San Joaquin (0.409)  Positive correlation to Solids  Fine, Silt and Clay  No significant correlation to Methylmercury  Lower Sacramento (0.02) /San Pablo (0.05)/ San Francisco Bay (0.09) /Coyote (-0.07) /San Joaquin Delta (-0.27) / Suisun Bay (0.37)

14.  Difference between Mercury and Methylmercury  No significant correlation  Mercury  Mining legacy  Sediment Loading

15.  In Developed Regions  e.g. Coyote and San Francisco Bay Watershed  No significant correlation  Industrial Wastewater Discharge  In Agricultural Regions  e.g. Lower Sacramento and San Joaquin Delta Watershed  Heavy metals, Temperature, Total Nitrogen, Solid phase, and Total Organic Carbon  On – site Methylation