The U.S. Geological Survey updated a data dashboard that shows long-term trends in groundwater contamination.
The USGS samples networks of wells in urban and agricultural settings across the country for pesticides, nitrates, metals, and other contaminants roughly every decade.
About 140 million people — almost one-half of the nation's population — rely on groundwater for public supply, irrigation, and agriculture. This mapper shows how concentrations of pesticides, nutrients, metals, and organic contaminants in groundwater are changing during decadal periods across the nation.