Toxic Substance Monitoring: Fish Tissue Monitoring Program

During calendar years 2004-2005, over 1400 fish samples were collected as a part of the fish contaminant monitoring program (Table 1 below is preliminary as of March 2006). The data shown in Table 1 includes samples collected and/or analyzed by Department of Natural Resources (WDNR) as a part of the normal fish contaminant monitoring program, by cooperators like the Great Lakes Indian Fish and Wildlife Commission (GLIFWC) or the Environmental Protection Agency (EPA), and under special projects and research. The 2004-2005 samples were collected from approximately 89 lake locations, 41 sites in flowing waters, and 27 areas of Green Bay and Lakes Michigan and Superior.

Each year the WDNR collects and analyzes samples of fish tissue from Wisconsin's inland waters and the Great Lakes, including their tributary streams. The objectives of the fish contaminant program includes protection of fish consumers by determining the levels of bioaccumulatory contaminants in the edible portions of fish and compare these levels to health guidelines as determined by the Wisconsin Division of Health.

Samples from the Great Lakes were analyzed for PCBs, pesticides, and mercury, while samples from river systems were primarily analyzed for PCBs and mercury. Fish samples from inland lakes were analyzed almost exclusively for mercury.

Fish consumption advisories are issued for certain species and sizes of fish from given areas where the concentrations of chemicals in the fish flesh exceed the health advisory levels. Fish contaminant data is also used to make natural resource and environmental management decisions.

Fish Advisory

Wisconsin issues general advice that applies to most inland waters where other pollutants or where mercury concentrations do not require more stringent advice. The general statewide advisory is based on US EPA's reference doses for mercury and typical levels of mercury found in Wisconsin fish based on the mercury concentration data that Wisconsin amassed over the last 30 years.

In addition to the statewide advisory that applies to most inland waters, more stringent consumption advice applies where fish have been found to contain higher concentrations of mercury or PCBs and other pollutants. The 2005 update of the Wisconsin Fish Consumption Advisory lists fish from 49 of the more than 2,000 lakes, river segments, and border waters tested (Table 2) due to the presence of PCBs and other organic chemicals. The 2005 update of the Wisconsin fish consumption advice lists fish from 94 specific surface waters due to higher concentration of mercury. The number of sites with fish consumption advice changed over the years in part due to monitoring, banning and limiting chemical usages, and also based on the protocols used to determine appropriate advice. See Table 2 for a list of health criteria used for Wisconsin's advisories.

Wisconsin provides information on fish consumption advice, including an advisory brochure, fishing regulations booklet, and in other publications.

Last Revised: August 2006