Freshwater fish contaminant monitoring

We analyze fish tissue from lakes and rivers throughout the state for various chemicals. The information helps to inform the public about safe levels for eating fish. Learn more by viewing these reports and databases.

Monitoring freshwater fish for toxic chemicals

We test freshwater fish for heavy metals, pesticides, PCBs, mercury, and dioxins, among other toxic chemicals that may harm humans or animals. The data tell us about the extent and magnitude of problems and how concentrations may be changing over time.

Since 2001, we have sampled fish at more than 170 sites, choosing sites to do exploratory monitoring where data are lacking. The state Department of Health uses the data to issue fish-consumption advisories.

Electrofishing for tissue samples

Long-term monitoring

We repeat sampling every 8 – 12 years to detect changes over time at these long-term sites:

  • Lake Chelan
  • Lake Washington
  • Spokane River
  • Okanogan River
  • Wenatchee River
  • Yakima River
  • Columbia River

Chemicals we analyze

We analyze fish tissues for a number of hazardous and persistent contaminants, such as:

  • Chlorinated pesticides (e.g., DDT, chlordane)
  • Dioxins and furans
  • Mercury
  • Polybrominated diphenyls (PBDEs)
  • Polychlorinated biphenyls (PCBs)

These chemicals are an unfortunate part of everyday lives. While potentially dangerous to the environment and to health, these chemicals are a byproduct of modern industry, fossil-fuel power generation, and manufacturing. Many of the contaminants, like PCBs, have been banned from use for decades, yet they persist in the environment because they break down slowly.

Other contaminants, like flame retardants and mercury, come from household goods, including cars and common consumer products. Much work has been done to reduce dangerous chemicals in the environment, and our monitoring helps identify where problems are the greatest. For example, the Washington Department of Health uses our results to determine potential health risks from eating contaminated fish.


Data are available through the Environmental Information Management (EIM) database under the Study IDs WSTMP (for years 2001-2012) or FFCMP (for more recent years), followed by two characters for the year, for example: WSTMP05 would be 2005 data, and FFCMP13 would be 2013 data.


Annual reports are in the EIM database under the "study publications" drop-down menu in the "study details" pages and on the Freshwater Fish Contaminant Monitoring publications page.