A Columbia University study found high levels of arsenic in drinking water in several U.S. states, mainly in the Midwest and West, including Michigan, South Dakota, Nevada, and California. Even concentrations below the limits set by the Environmental Protection Agency (EPA), which sets the maximum level at 10 micrograms per liter in public water systems, have been found to be associated with low birth weight and other adverse effects on pregnancy. Experts call for stronger controls, especially in areas that depend on groundwater exposed to natural contamination. In fact, arsenic occurs naturally in soil and sediment, and can infiltrate public water systems.
As Anne Nigra, PhD, of Columbia University’s Mailman School of Public Health explains, high concentrations of arsenic can cause serious conditions such as cancer, skin disease, and an increased risk of hypertension and diabetes.
Vasilis Vasiliou, professor of environmental health sciences at the Yale School of Public Health, explained that in some states, “elevated arsenic levels are found primarily due to natural geology, with human activities also contributing.” He adds that, “Arsenic occurs naturally in rocks and can pass into groundwater in regions with volcanic, mineral-rich or sedimentary formations,” prevalent in the Southwest, Midwest and some areas of California’s Central Valley. The expert points out that many affected communities get their drinking water from wells, which are more susceptible to arsenic contamination than surface water.
