Statewide Advice - Safe Eating Guidelines

In 2001, Wisconsin began to provide consumption advice on eating fish caught from all Wisconsin waters. Prior to that, advice was given only for specific surface waters. The change reflects recent scientific findings and the recommendation of Wisconsin's top medical official to use a standard that better protects human health. It is also based on the mercury concentrations found in Wisconsin fish.

As a result, most - but not all - inland waters carry the same statewide advice for how many meals of fish people can safely eat while reducing their risk of exposure to mercury. There are different recommendations for sensitive populations [includes women of child-bearing age, pregnant women, and young children] and for all other individuals. Wisconsin's new statewide advice or safe eating guidelines apply to most of Wisconsin's inland (non-Great Lakes) waters.

The changes in mercury advice result from the National Research Council's report, "Toxicological Effects of Methylmercury" (2002). This report concluded that the standard the U.S. Environmental Protection Agency's (EPA) reference dose is appropriate to determine whether to issue consumption advice for fish. A reference dose is defined as "an estimate of a daily exposure to the human population (including sensitive subpopulations) that is likely to be without a risk of adverse effects when experienced over a lifetime."

The use of this new reference dose required that consumption advice be issued when fish exceeded 0.05 parts per million (ppm) mercury. Most of Wisconsin's fish contain at least that amount based on statewide testing. Mercury concentrations vary between species or different types of fish. Thus, different levels of consumption advice is appropriate for most waters and varies with the species of fish and the person eating the fish.

The National Research Council also concluded that developing fetuses are by far the group most at risk from mercury because of the sensitivity of their developing nervous system. Scientists estimated that 60,000 children born each year in the United States are at risk for neurological and learning problems because their mothers ate large amounts of mercury-contaminated fish and seafood during their pregnancy.

Some waters have fish that have been found to contain higher concentrations of mercury. These waters have more stringent advice or exceptions to the safe-eating guidelines. 2007 mercury advisory [PDF 56KB]

Some waters have fish contaminated with polychlorinated biphenyls (PCBs). Specific advice is provided on how many meals you can safely eat of species caught from waters contaminated with PCBs, such as Lakes Michigan and Superior, some large rivers and other surface waters. In those waterbodies, anglers should follow the specific consumption advice for PCBs. 2007 PCB advisory [PDF 106KB]

For more information on mercury in fish, please contact Candy Schrank, Aquatic Toxicologist, (608) 267-7614.