A new report from the Natural Resources Defense Council says Minnesota and other Midwestern states have dangerously high levels of atrazine in drinking water.
NRDC used data from the federal Environmental Protection Agency to point to high spikes of atrazine after the widely used pesticide is applied to farm fields in early summer.
Paul Wotzka is a hydrologist who has studied water quality in southeastern Minnesota for years. He says animal tests show atrazine in small amounts can cause birth defects.
"If you were pregnant mother, drinking water in June and you had these high spikes of atrazine in your water, you would want to know about them," he said.
Wotzka says private wells are rarely tested, and public drinking water supplies are only tested once a year.
The Minnesota Pollution Control Agency has said that atrazine is found at very low concentrations, well below state standards.