Under the Dome

Warnings lifted on wells near coal ash ponds

Duke Energy retired Riverbend power plant in Mount Holly coal ash primary basin, photo during a media tour on May 19, 2014.
Duke Energy retired Riverbend power plant in Mount Holly coal ash primary basin, photo during a media tour on May 19, 2014. rlahser@charlotteobserver.com

UPDATED State health officials are lifting their do-not-drink notices for some private drinking water wells located near Duke Energy power plants, saying they had erred on the side of caution over the past year.

The notices were based on the levels of two substances in the water -- hexavalent chromium and vanadium – that might come from Duke’s coal ash ponds across the state. But similar levels of those contaminants are present in municipal drinking water across North Carolina and the entire country.

Dr. Randall Williams, a deputy secretary at the state Department of Health and Human Services, told the Environmental Review Commission on Wednesday that officials discovered that many water systems would exceed the levels the agency had used to issue the warnings.

"We knew at the time those were very cautious levels," Williams said, particularly since the wells are close to coal ash ponds that are leaking.

In 2008, the U.S. Environmental Protection Agency considered whether to set limits on hexavalent chromium, which it has said can cause cancer in humans if ingested in drinking water, because it has caused tumors in rats and mice, and due to some evidence of stomach cancers in humans. But North Carolina, like the federal government, hasn’t set limits on how much of it is safe in drinking water. Williams said the EPA plans to weigh in on the health risks in December.

DHHS, acting under the direction of a new state law regulating coal ash cleanup, established its own benchmark: a level that might cause one cancer in 1 million people over a lifetime of exposure. The state health agency tested 360 wells. Of those, 330 exceeded the screening levels for several substances, and the agency recommended that water not be used for drinking or cooking.

As of Wednesday, DHHS reports that 235 of those wells now no longer have do-not-drink recommendations. Ninety-five wells will still be designated as not for drinking because of the presence of other constitutents aside from hexavalent chromium or vanadium.

Uncertainty around what is safe has been stressful for the people who use those wells, and have been on Duke-supplied bottled water for months. Duke Energy reports it is providing bottled water to 388 homes.

Some residents continue to express skepticism about whether or not the water is safe.

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