Problem Water: Mercury

A thermometer, which uses mercury to gauge the temperature

Despite what your eyes may be telling you, the calendar says that it’s spring. Once the weather begins to cooperate, many of us will be looking to spend some time out on the lake, with a fishing rod in one hand and a cold brew in the other.

Unfortunately, eating fish from the wrong lakes can be hazardous to your family’s health.

The problem stems from mercury contamination. Burning coal, mining, and incineration of mercury-containing products such as wiring devices and fluorescent lights all release mercury pollution. Human sources account for about 70% of the mercury in the air. This air pollution eventually makes its way to lakes and rivers where it’s converted to methylmercury by bacteria. Fish absorb methylmercury from their food, allowing the mercury to bind to proteins in fish tissue, including the muscle that we eat. When you haul that monster into your boat, you are hauling all that mercury right along with it, and no method of preparing the fish can reduce the amount of mercury within.

The problems arising from mercury poisoning are sinister and varied. Adults who have consumed too much mercury may experience numbness or a tingling sensation in the lips, tongues, fingers, or toes, a lack of coordination, tachycardia, and skin discoloration. Contaminated fish pose the most danger for young children and women who are pregnant or may soon become pregnant. Mercury is toxic to the nervous system, and is particularly harmful to the nascent nervous systems in children and developing fetuses. Affected children may face loss of hair, teeth, and nails, transient rashes, and kidney dysfunction.

Clearly, this is a major problem for people who enjoy fish as part of their balanced diet. So what can you do to avoid the dangers? The best thing you can do is to be informed. The Minnesota Department of Health publishes guidelines for safe consumption levels, and websites such as can help you find out which lakes in your area are safe, which are unsafe, and which have yet to be tested.

While the Environmental Protection Agency follows very strict procedures in testing water supplies for mercury levels, Water Doctors does offer a test for mercury (along with nearly every other possible contaminant you can think of). If you are concerned about the integrity of the water in your home, have your water tested. To find out what you can do to help keep Minnesota’s lakes and rivers free of mercury and other contaminants, contact the Minnesota Pollution Control Agency. Help make sure the only mercury level that’s rising this summer is the one safely inside your thermometer.

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