This spring and summer, U.S. Geological Survey scientists waded into 100 Midwest streams to test for hundreds of chemicals used in farming, including nutrients, pesticides like atrazine and glyphosate, and livestock hormones. The results from the study are trickling in. But preliminary findings indicate that from May through early July, 21 percent of the region’s streams contained very high levels of nitrogen in the form of nitrates.
Eleven miles northeast of Centralia, Mo., five U.S. Geological Survey scientists don waders and bright reflective life jackets to wade into Goodwater Creek. Plenty of fish live in the stream’s murky slow-moving waters, along with snakes, crayfish, mussels and snapping turtles. On this overcast morning, the team collects water samples and checks submerged cages of fathead minnows for eggs.