The Mad Hatter in Lewis Carroll’s classic, Alice’s Adventures in Wonderland, was a humorous character with a good excuse for his misconduct - he suffered from chronic mercury poisoning. But the same story a little closer to home isn’t so funny. Although no one has yet described a “mad angler” syndrome in Northern Wisconsin, you can’t ignore the grumblings of anglers who are becoming angry over the growing list of lakes which carry warnings from the Department of Natural Resources that their fish are unsafe to eat due to high mercury levels.
As of this writing, the DNR’s fish advisory for mercury contamination stands at 321 lakes and river segments and includes many favorite Wisconsin fishing waters such as Lake Wissota, Tomohawk Lake, Trout Lake, Lake Monona and segments of the Wisconsin, Wolf, Black and St. Croix rivers. Most lakes in the state have yet to be tested, but so far roughly one out of every three has had some fish - most often walleyes - with unsafe mercury levels.
The mercury that ends up in our lakes and fish comes from a variety of sources, both natural and human. While natural levels of mercury have never been a health threat in our food, man-made levels have. Studies of the sediments (soil) at the bottom of northern Wisconsin lakes show a quadrupling of mercury since the late 19th century, when industry came to our state. High mercury levels in otherwise pristine lakes of the far north reveal the importance of mercury fallout from the air, similar to acid rain, which originates with air pollution far upwind.
The tale told by lake sediments begins at the smokestacks of coal-burning power plants, waste incinerators, and factories which are among the largest sources of airborne mercury releases. Although mercury in industrial wastewater has contaminated lakes and ocean waters in the past, direct releases are tightly regulated today. In stark contrast, federal and state mercury air emission regulations don’t even consider the most common risk of exposure to mercury in high concentrations - namely, by eating fish.
A recent and very comprehensive study by the Environmental Protection Agency documented that power plants and solid and medical waste incinerators are the nation’s largest sources of mercury emissions by far, combining to make up about 80 percent of all emissions. In Wisconsin coal-fired utility power plants are by far the largest collective source, accounting for about 40 percent of all mercury air pollution in the state annually.
Mercury is a neurotoxin, meaning that it affects the brain and nervous system. Small children and especially fetuses are the most at risk for damage from mercury poisoning because their brains are still developing. Numerous studies warn that pregnant women who eat fish from high-mercury Wisconsin waters could have children with reduced or delayed development in the areas of memory, language, coordination and attitude depending on the amount of fish eaten. Impacts on adults who eat gamefish are less likely; although in the pages ahead you’ll find the story of a man who experienced severe consequences after eating unlimited amounts of fish from a high-mercury lake near Hayward, Wisconsin.
The
purpose of this report is not to create hysteria or scare anyone off Wisconsin
waters. In fact, Wisconsinites’ love of fishing and eating sportfish
may be the strongest reason that measures are taken to reduce mercury emissions
to our waters and make our fish safe to eat. It’s as plain as having
clean air to breathe - anglers have a right to eat the fish they catch
from Wisconsin’s lakes and rivers.
It’s about protecting what we love and value about Wisconsin - our beautiful, abundant natural resources. Mercury pollution puts Wisconsin waters, public health and tourism dollars at risk for no good reason. Sporting groups, tourism interests, health professionals and at-risk populations will need to work together with industry and regulators if we hope to make Wisconsin fish safe for our children and future generations. While nobody should panic over mercury pollution, we also shouldn’t hesitate to demand that state agencies like the Department of Natural Resources and the legislature should take immediate steps to reduce mercury emissions, at least from the largest sources, and better educate the public.
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