California Department of Fish and Wildlife


Problem Statement

Pan of Mercury

Photo by Rick Humphreys

Mercury is found throughout the San Francisco Bay-Delta estuary and its watershed at elevated concentrations in water sediment and biota. Mercury is of concern from both an environmental and human health perspective. Methylmercury is the toxic form of mercury. Effects on fish include: death, reduced reproductive success, impaired growth and development, and behavior abnormalities. Methylmercury exposure in birds can cause reproductive effects, and in plants can in plants can cause death and sublethal effects. Finally methylmercury effects on humans include neurotoxicity in adults and developmental problems in fetuses and children.

ERP has supported projects that:

Current projects include:

  • A pilot mine remediation project
  • A pilot study looking at methylmercury in seasonal and permanent wetlands to determine best management practices
  • A pilot study to remove mercury from dredge tails, cleaning the gravels for use in the nearby creek as spawning gravels
  • Support for the Central Valley Regional Water Control Board’s Technical Advisory Committee for the Methylmercury Total Maximum Daily Load

Mercury Related Links

California Office of Environmental Health Hazard Assessment

California Department of Public Health

Central Valley Regional Water Quality Control Board

California State Water Resources Control Board

California Department of Conservation

U.S. Geological Survey

U.S. Environmental Protection Agency

San Francisco Estuary Institute

Delta Tributaries Mercury Council

Experimental Lakes Area

For more information, contact Carol Atkins at or (916) 445-0074.