Source: U.S. Geological Survey

Editor's note: The studies were conducted in Indiana, Texas, Maryland, North Carolina, Georgia, Massachusetts, Oregon, Nevada and Colorado.

Low levels of certain man-made chemicals remain in public water supplies after being treated in selected community water facilities.
Water from nine selected rivers, used as a source for public water systems, was analyzed in a study by the U.S. Geological Survey (USGS).

Most of the man-made chemicals assessed in this study are not required to be monitored, regulated or removed from water treatment facilities.

Scientists tested water samples for commonly used chemicals, including pesticides, solvents, gasoline hydrocarbons, personal care products, disinfection by-products, and manufacturing additives.