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Data from nearly 1,400 drinking wells across North Carolina show excessive levels of carcinogen
Some North Carolina wells contain levels of hexavalent chromium in excess of safety standards.
November 21, 2019
A new study that combines measurements from some 1,400 drinking water wells across North Carolina estimates that more than half the wells in the state's central region contain levels of cancer-causing hexavalent chromium in excess of state safety standards. The NSF-funded findings are published in Science of the Total Environment.
"Though often thought of as a byproduct of industrial contamination, hexavalent chromium can form naturally in groundwater, depending on the local aquifer geology and water chemistry," said geochemist Avner Vengosh of Duke University.
Other studies have identified naturally occurring hexavalent chromium in groundwater in Arizona, California, Argentina, Brazil, Greece, Italy and Mexico.
Only a single North Carolina well in the study violated the maximum contaminant level for total chromium set by the U.S. Environmental Protection Agency of 100 micrograms per liter. But the North Carolina Department of Health and Human Service's much lower health advisory level -- 0.07 micrograms per liter -- is set to protect against a one-in-one-million risk of cancer over a 70-year life span. That level of hexavalent chromium was exceeded by 470 of the 865 wells that were measured./.../
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