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By Keith Matheny, Detroit Free Press
Posted Apr 9, 2017 at 5:00 AM
DETROIT — It’s not supposed to be like this.
Although advisories about toxic mercury in fish have continued in the Great Lakes, with recommendations to limit consumption of certain species to a few times per month, the amount of mercury found in fish tissues has dropped steadily over decades since the 1970s.
That corresponded with the reduction of pollution coming from Midwestern smokestacks as regulations tightened, pollution-prevention technology improved and coal-fired factories and power plants went offline. |
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But over the past several years, the decline has reversed. Scientists are finding mercury levels rising in large Great Lakes fish such as walleye and lake trout. Curiously, it’s occurring in fish in some locations but not others. Researchers are trying to figure out why.
The mercury levels are not surpassing U.S. Environmental Protection Agency thresholds, but researchers want to determine whether what they are seeing is temporary or a trend that will worsen.
The answer has large ramifications for the Great Lakes’ sports-fishing industry.
Mercury is a heavy, silvery metal, unusual in that it’s liquid at room temperature. It’s naturally occurring, but is rare to find uncombined with other elements. |
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