A new study from Duke University estimates that over half of drinking wells in the Piedmont have levels of a chemical compound above the state's health advisory level.
Researchers at Duke used a large dataset of measurements to create a model that predicts levels of hexavalent chromium, a known human carcinogen. Dr. Avner Vengosh says hexavalent chromium can occur naturally in groundwater and this area is especially prone to higher levels.
“So what we found is that the geology of the aquifers plays a very important role in the presence of hexavalent chromium and therefore the Piedmont is where we found the highest abundance,” he says.
Vengosh says the study also emphasizes a discrepancy in standards that needs to be resolved.
The Environmental Protection Agency isn't aligned with the state on what is considered safe. North Carolina's standard was created to protect against a one in a million risk of cancer over a 70-year life span. The EPA does not specifically single out hexavalent chromium in its guidelines.