A veritable hodgepodge of chemicals — including cocaine, synthetic estrogen and antidepressants — have reportedly been found in isolated Minnesota lakes.
The Minneapolis Star Tribune reports that the findings indicate that some contamination has become the norm for virtually all of the waters in the “Land of 10,000 Lakes.” Among the 50 lakes across Minnesota that were randomly selected and tested for 127 compounds, all but three tested positive for varying concentrations of one of more chemicals. Cocaine was found in 32 percent of the lakes, while the insect repellent DEET was found in 76 percent of the waters.
“That was astonishing,” Mark Ferrey, lead researcher of the new report released Monday by the Minnesota Pollution Control Agency, told the newspaper. “We need to look in the mirror. No matter what we use, it finds its way into the environment.”
Ferrey said the impact of the contaminants on aquatic life and humans is far less understood. A growing number of studies have found that some chemicals, particularly those that resemble hormones, can have a strong biological effect on some species at even tiny concentrations, the newspaper reports.
One experiment conducted in a Canadian lake found that two years after synthetic estrogen was added at a concentration of five parts per trillion — the equivalent of adding five drops to 15 or 20 swimming pools, Ferrey said — the fathead minnow population crashed and its trout numbers began to decrease.
Ferrey said he was astonished that cocaine was discovered in nearly one-third of Minnesota lakes tested, some of which had little human use. Cocaine was the third-most common chemical found, following DEET and Bisphenol A, a chemical from plastic. Ferrey was also surprised to find carbadox, an antibiotic used in swine that turned up in 28 percent of the lakes, including some that had no connection to feedlots or pig farms. Carbadox is also a carcinogen that has been banned in Europe and Canada, Ferrey said.