Toxics in Fish

Fish in aquatic systems can be exposed to and accumulate toxic chemical pollutants, causing disease, and posing a threat to humans who consume them. The indicators for this Vital Sign track a few important pollutants in Puget Sound and are considered signs and symptoms of fish health related to exposure to these pollutants. The toxic chemicals pollutants tracked in Puget Sound fish include those that last for a long time in the ecosystem and which increase in predators as the chemicals move through food webs. Measuring these pollutants in fish tissues tells us whether current levels are harmful to the fish or the predators that consume them and whether they are safe for humans to eat.

The Toxics in Fish Vital Sign focuses on four classes of pollutants in several fish species and includes:

  • PCBs (Polychlorinated biphenyls) - PCBs are man-made organic chemicals that were produced domestically from 1929 until manufacturing was banned in 1979. PCBs were used in hundreds of industrial and commercial applications, and are found in trace amounts today.
  • PBDEs (Polybrominated diphenyl ethers) – PBDEs are used as flame retardants in a wide array of products such as electronics, motor vehicles parts, plastics, foams, and textiles. The production of some types of PBDEs is banned and their use in consumer products is restricted.
  • PAHs (polycyclic aromatic hydrocarbons) – PAHs are found in petroleum products and also produced through burning fossil fuels.
  • EDCs (Endocrine Disrupting Compounds) – EDCs are a wide class of compounds that impact reproduction and development.

Key Vital Sign Messages

Biomagnification of contaminants in the food web. Seattle Post-Intelligencer.

  • Chemical contamination continues to be widespread in Puget Sound, potentially impairing the health of many species, including crab and shrimp, bottomfish, adult and juvenile Chinook salmon, small fish like Pacific herring, and apex predators like Southern Resident Killer Whales. The health of people who eat fish and shellfish caught in some areas of Puget Sound may also be at risk because of the contaminants. Because of the potential for harm there are public health advisories to limit the consumption of Puget Sound Chinook salmon, as well as bottom fish and Dungeness crab from urban embayments.
  • A selected group of harmful chemicals are routinely monitored in species from a range habitats in Puget Sound. These include persistent pollutants like PCBs (a type of oil that was previously used in industrial products) and flame retardants (PBDEs), hydrocarbons (PAHs) that are continually released into Puget Sound, and some legacy pesticides (like DDTs) and heavy metals (including mercury, lead and others).
    • PCBs levels are high enough in the pelagic food web to harm herring, Chinook salmon, and Southern Resident Killer Whales, and limit the amounts people can safely eat. The levels have been consistently high for many years.
    • PBDEs appear to be declining in the pelagic food web.
    • Juvenile Chinook salmon leaving their natal rivers through urbanized estuaries to reach the ocean may be harmed by exposure to these chemicals
  • Concern is growing regarding a wide range of chemicals that are associated with household products like pharmaceuticals, personal care products, plastics, tires, and more. A relatively small number of them are monitored in the environment but certainly not all. Some are suspected to cause harm to fish. Examples include antibiotics, antidepressants, phenols, and cancer treatment drugs.
  • Contaminants are released into the environment from daily human activities and carried into Puget Sound through stormwater runoff, municipal wastewater effluent and leaky septic systems, and from atmospheric deposition and agricultural runoff.
  • There is a need for ecosystem scale and equitable approaches to prioritize and clean up contaminated sites and reduce chemical inputs to Puget Sound. These actions will ultimately improve the health of Chinook salmon, the resident orca whales that feed on them, and protect human health.

Strategies, Actions, and Effectiveness

Other Resources

Contributing Partners


James West, Toxics in Biota program at the Washington Department of Fish and Wildlife. Key messages were reviewed by the PSEMP Toxics Work Group
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