Statewide Mercury Program

Addressing Mercury in California's Waters

Many of California’s waters are contaminated by mercury (also called quicksilver), a heavy metal and potent neurotoxin that is harmful to both humans and wildlife. Mercury builds up in the bodies of fish that swim in waters with even small amounts of mercury; and in the bodies of humans who eat contaminated fish. In our state, sources of mercury typically include:

• Historic mercury and gold mining activities
• Atmospheric deposition from both local and global airborne sources
• Discharges from wastewater treatment plants that cannot remove mercury from industrial processes or mercury thermometers broken in a sink

Women of childbearing years and children are most at risk from mercury poisoning. For more information, see Safety Tips for Women and Children and General Health Advice for People Catching and Eating Sport Fish in California.

Statewide Mercury Control Program for Reservoirs

Water Board staff from around the state are working to develop a regulatory program to address mercury contamination in California reservoirs. Four public scoping meetings were held in March of 2012.

• Public Scoping Presentation
• Scoping Comments
• Documents discussed at the meetings:
  • Project Summary
  • Map and list of California reservoirs impaired by mercury
  • Mercury Control Program fact sheet
• We are accepting comments on the scoping materials until March 30, 2012. For instructions on submitting comments on this proposed program, please see the official public notice
• For more information on this topic, please contact Carrie Austin, (510) 622-1015

Mercury Objectives Project: Setting Standards for Safe Amounts of Methylmercury in Tissues of Fish

The State Water Board is developing a set of standards (“objectives”) for safe amounts of methylmercury in the tissues of fish. These objectives will inform mercury policy, mercury pollution prevention plans, and water quality permits. They will apply to California’s inland waters, enclosed bays, and estuaries; and protect humans and wildlife that consume locally caught fish.

• Development of Methylmercury Objectives
  Drafted informational document from public scoping meeting (2007).
• Public Comments Received (February 2007)

No meetings are scheduled at this time. Watch this page for more information!

Ongoing State Efforts to Reduce Mercury Contamination

In addition to the projects noted above, the State Water Resources Control Board (State Water Board) and the affiliated Regional Water Quality Control Boards continue ongoing efforts to reduce concentrations of mercury in our waters. The California Department of Public Health and the Office of Environmental Health Hazard Assessment are educating people who eat local fish, about the types and amounts of fish that are safe and unsafe to eat.

Total Maximum Daily Loads (TMDLs) for Mercury in our Waters

The Water Boards adopt and implement comprehensive pollution control plans, known as “total maximum daily loads,” or TMDLs. A TMDL identifies the amount of a pollutant that a water body can hold and still be safe for uses by humans and wildlife.

Completed Mercury TMDLs (including date approved by U.S. EPA)

• Cache Creek, Bear Creek, and Harley Gulch Mercury TMDL (Central Valley Region, 2007)
• Clear Lake Mercury TMDL (Central Valley Region, 2003)
• Guadalupe River Watershed Mercury TMDL (San Francisco Bay Region, 2010)
• Sacramento-San Joaquin River Delta Methylmercury TMDL (Central Valley Region, 2011)
  
• San Francisco Bay Mercury TMDL (San Francisco Bay Region, 2008)
• Sulphur Creek Mercury TMDL (Central Valley Region, 2009)
• Walker Creek Watershed Mercury TMDL (San Francisco Bay Region, 2008)

Mercury TMDLs in Development

• Big Bear Lake Mercury TMDL (Santa Ana Region)
• Los Angeles Area Lakes TMDLs (Los Angeles Region, established by the U.S. Environmental Protection Agency)

( Updated 4/12/12 )