Chemicals in Fish

Certain chemicals can be of potential health concern because of their toxicity and their ability to accumulate in fish tissue. Angler fishing in a river with smokestack and rain clouds in the background. Harmful chemicals enter the environment through natural processes, industrial and agricultural use, mining, spills, and improper disposal. Fish can take in these chemicals from the food they eat or the water in which they live.

The majority of fish consumption advisories in California are issued because of mercury, followed by polychlorinated biphenyls (PCBs) and, in a few cases, legacy pesticides (pesticides that are no longer used but remain in the environment), selenium, or polybrominated diphenyl ethers (PBDEs).

You can reduce your exposure to harmful chemicals by following our advisories and tips for catching, preparing, and cooking fish.


  • Mercury is a metal found in coal, rocks, and soil, and has been detected in fish all over the world.


  • Polychlorinated biphenyls (PCBs) are industrial chemicals previously used in electrical transformers, plastics, and lubricating oils.

  • Learn more about PCBs.

Legacy pesticides: Chlordanes, DDTs, Dieldrin, and Toxaphene



  • Polybrominated diphenyl ethers (PBDEs) are a class of flame retardants historically used in a variety of consumer products including furniture, textiles, automotive parts, and electronics.

  • Learn more about PBDEs.

Fish Advisory Map

View maps of current statewide and site-specific advisories

Advisory Map

Fish, Ecotoxicology and Water Section

Sacramento Office
1001 I Street
Sacramento, CA 95814
Phone: (916) 423-7572

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