Conservation and public health groups filed a lawsuit today to force the Trump administration to develop required water quality standards for atrazine, a cancer-linked pesticide found at dangerous levels in thousands of U.S. waterways and in drinking-water supplies. … Atrazine is the nation’s most widespread pesticide water pollutant. According to a new Center for Biological Diversity report, the pesticide contaminates 25% of all river miles in the continental United States at levels the Environmental Protection Agency recognizes as harmful to aquatic life. Atrazine pollution is caused by industrial agricultural operations using tens of millions of pounds of the pesticide each year. Today’s lawsuit challenges the lack of water quality protections in American waterways as required under the Clean Water Act. The Act requires the EPA to develop water quality standards for pollutants like atrazine. The agency initiated but failed to complete that step in 1999.