The herbicide is showing up at low levels, including in the BWCA, apparently carried by wind and rain.

The widely used weed-killer atrazine is showing up in pristine lakes in northern Minnesota far from farm country, and scientists believe the chemical is falling out of the sky.

In the first statewide study of pesticides in Minnesota lakes, government scientists discovered small amounts of atrazine in nine out of 10 lakes sampled, including some in or near the Boundary Waters Canoe Area Wilderness.

“To some people, it is a bit of a surprise, but the concentrations are low, very low,” said Steven Heiskary, a research scientist with the Minnesota Pollution Control Agency (MPCA).

The study shows that pesticides have joined the list of unwanted substances, such as mercury and acid rain pollutants, that are spread vast distances by wind and rain to some of the wildest places in the state.

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