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San Francisco Bay PCBs TMDL Project


High levels of PCBs in San Francisco Bay fish prompted state health officials to advise the public to limit their consumption of Bay fish, beginning in the mid-1990s. PCBs also harm fish and other wildlife in the Bay. In 2008, the San Francisco Bay Regional Water Quality Control Board (Water Board) adopted a clean water action plan (a TMDL) for PCBs in the Bay. This plan requires municipalities, industry, and others to take action to reduce PCBs in the Bay.

Polychlorinated biphenyls, called PCBs, are oils to which chlorine has been added to keep them from breaking down in industrial applications. Because PCBs are stable at high temperatures, they had numerous industrial uses beginning in the 1920s. After their harmful effects became known, Congress banned the manufacture and most uses of PCBs in 1979. Some PCBs are still in use today, primarily by electric utility companies in transformers.

PCBs are a problem in the Bay because they are toxic, persist in the environment, and accumulate in the tissues of fish, wildlife, and humans. Studies with animals show that high levels of PCBs could harm the liver, digestive tract, and nerves; and could affect development, reproduction, and the immune system. PCBs have been found to cause cancer in some animal studies. PCBs in the Bay are found more often in bottom sediment more than in the water. This means that they begin to accumulate at the very base of the food web. Bottom-dwelling organisms transfer PCBs to fish, diving ducks, and other marine life - and on up to large sport fish and humans who catch and eat them.

Much of the PCBs pollution in the Bay happened decades ago, before the potential health and environmental effects of PCBs were widely known. Today, a smaller amount of PCBs still enters the Bay from these source categories, shown in the diagram at right:

  • Drainage from the Central Valley
  • Municipal and industrial wastewater
  • Storm drains and stormwater runoff
  • Disturbance of buried Bay sediments by dredging or erosion.


LandSat map of the Bay region








TMDL Approved by USEPA

On March 29, 2010, the U.S. Environmental Protection Agency approved a TMDL for Polychlorinated Biphenyls in San Francisco Bay. The TMDL was approved by the State Office of Administrative Law and became effective on March 1, 2010. The Water Board is now implementing the TMDL on the variety of fronts described below.

Regulatory Documents
The San Francisco Bay PCB TMDL was considered and adopted by the Regional Water Quality Control Board (Water Board) at hearings on September 17, 2007 and February 13, 2008. It was adopted by the State Water Resources Control Board on October 20, 2009.

  • The TMDL is contained in this Basin Plan section.
  • The TMDL was adopted by the Water Board in Resolution R2-2008-0012
  • Supporting documentation is contained in the Final Staff Report (pdf, 5MB)
  • February 13, 2008 Water Board Meeting Minutes, Item 8 (adoption of the TMDL)
  • Transcript from the September 17, 2007, Water Board meeting (consideration of the TMDL)
  • The TMDL was adopted by the State Water Resources Control Board in Resolution R2-2009-0076

TMDL Implementation

This section summarizes how key implementation actions are carried out.

Municipal Regional Permit – Permit for municipal stormwater sources of PCBs
The NPDES Municipal Regional Stormwater Permit (see Provision C.12), adopted November 18, 2015, requires municipalities in Alameda, Contra Costa, San Mateo and Santa Clara Counties and the cities of Fairfield-Suisun and Vallejo (Pemittees) to reduce controllable sources of PCBs that can be mobilized by stormwater runoff and transported to receiving waters. In the previous permit term, Permitees were required to do several pilot-scale projects and evaluate their effectiveness in reducing loads of PCBs. Major PCBs-related requirements for the 2015-19 permit term include:

  • Implement PCBs control measures (source control, stormwater treatment, and pollution prevention), so that PCBs loads are reduced by 3 kg/yr by June 30, 2020
  • Evaluate whether PCBs are present in sealants used in storm drain or roadway infrastructure
  • Implement programs for controlling PCBs when structures bult 1950-1980 are demolished.
  • Take action to reduce the health risk to consumers of Bay-caught, PCBs-containing fish.

Annual reports documenting the Permitees' actions are found here

Also, Permittees monitor for PCBs in surface water and sediments. Results are documented annually in reports found here . The data will be used to estimate loads of PCBs and other contaminants from local tributaries and stormwater conveyances and to track these loads over time.

Watershed Permit – Discharge permit for municipal and industrial wastewater sources of PCBs
The Watershed Permit (R2–2012–0096,) requires both municipal wastewater and industrial wastewater dischargers to take certain actions to reduce PCB discharges to the San Francisco Bay. Some of the Permit’s requirements are: identify and manage controllable sources of PCBs; use best management practices to maintain optimum performance for solids removal; use updated analytical methods to test for PCBs; and undertake a program to reduce the health risks for people who eat San Francisco Bay fish contaminated with PCBs and mercury.

PCBs in Cleanup, Remediation, and Spill Sites
Guidelines for implementing the TMDL during site investigations and cleanups are given here. The guidelines are applicable to spill removals, voluntary cleanups and brownfield investigations. State and federal cleanup actions, and anywhere PCBs are present in soil. We update the guidelines periodically; please send comments to the contact at the bottom of this web page.

Fish Consumption Risk Reduction Activities
Both the Watershed Permit and Municipal Regional Permit require dischargers to take action to reduce public health impacts from consuming PCBs– and mercury– containing fish. These entities, along with CA Dept. of Public Health, conducted the San Francisco Bay Fish Project which funded APA Family Services, California Indian Environmental Alliance, Kids for the Bay, and Greenaction for Health and Environmental Justice to help reduce people's exposure to PCBs and mercury from consuming SF Bay fish. Among their accomplishments is the video below. https://www.youtube.com/watch?v=CuQ20c7oo5M&feature=youtu.be

The Project’s final report was completed in 2012.

Since then, dischargers have taken a variety of actions, ranging from funding focused outreach to at–risk communities to posting signage at fishing locations. These activities are summarized in the dischargers’ annual reports.


Ongoing Monitoring of Fish and the Bay
To track progress on how PCB concentrations in the Bay and its fish are changing over time, the Regional Monitoring Program (RMP) measures PCBs (and many other contaminants) in water, sediment, and fish tissue collected at several locations around the Bay each year. You can view and download these data for yourself using their versatile data download tool.

The RMP has monitored contaminants in prey fish (small fish consumed by birds or larger fish) for several years, because these small prey fish, which tend to stay in localized areas, provide useful information on the spatial and temporal patterns of contamination in the Bay. Moreover, these prey fish are consumed by many birds and larger fish, so they provide an early warning for contamination higher in the food web. Small fish monitoring data and interpretation are contained in a summary report.

Since 1994, the RMP has also been monitoring the concentrations of PCBs and other contaminants in sport fish, which are commonly consumed by humans. A 2011 report comparing the concentrations of contaminants in sport fish caught in the Bay to those caught offshore is also available. The figure below shows how PCBs concentrations in sport fish change through time in different parts of the Bay and how these concentrations compare to the 10 parts per billion fish tissue target from the TMDL.


General Information about PCBs and this TMDL

Health Information, Fish Consumption Advisories, and Outreach to Consumers of SF Bay Fish

Information about PCBs in Caulk

Proposition 13 Grant-Funded Studies: Urban Stormwater Best Management Practices (BMPs) 2010
This project’s goal was to assist municipalities in implementing the San Francisco Bay mercury and PCB TMDLs through the development of specific information on drainage systems, sediment loads, distribution of mercury and PCB contamination, urban runoff loads, and BMP function in relation to trapping or removing mercury and PCBs. Click here for the project web site.

U.S. Environmental Protection Agency

For more information contact:
Jan O’Hara
Water Resource Control Engineer