The waters of Lake Michigan are contaminated with prescription drugs and personal care products at higher levels that can be considered safe for the environment, new research published in the journal Chemosphere has warned.
Chemical substances were discovered a couple of miles away from Milwaukee's sewage outfalls, which might mean that the Great Lakes are not diluting the substances as researchers had expected.
The team of scientists took samples of effluent from two sewage outfalls, as well as water and sediment from the lake. A total of 27 chemicals were found in the samples, but four of them were most common -- caffeine; a drug used to treat diabetes, called metformin; the antibiotic sulfamethoxazole; and triclosan, a compound used in the production of soaps and toothpastes.
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According to Rebecca Klaper, associate professor at the University of Wisconsin-Milwaukee and co-author of the study, the effects these substances have on fish and the ecosystem as a whole is unclear and their presence in water at such concentration levels was unexpected. However, it is possible that they have a serious impact, since they do not appear to be diluted, she added.
Another potential cause for concern is the fact that the city of Milwaukee takes its drinking water from Lake Michigan. So far no traces of pharmaceuticals have been detected in the city's drinking water, sources from the Milwaukee Water Works told the Great Lakes Echo.