Coal Ash Is Not Responsible For The Presence Of Cancer-Causing Chemical In North Carolina Wells: Study

Posted: Oct 29 2016, 8:27am CDT | by , Updated: Oct 30 2016, 11:52am CDT, in News | Latest Science News

 

Coal Ash is not Responsible for the Presence of Cancer-Causing Chemical in North Carolina Wells, Study
Credit: Duke University
 

The interaction of groundwater with volcano rocks across the Piedmont region is likely linked to water contamination.

An abundance of Hexavalent chromium, a toxic chemical compound, was detected in drinking-water wells of North Carolina last year. Given the fact that those wells were located near the coal plants, it was assumed that the elevated levels of chromium in coal ash might have caused water contamination in the state. But a report suggests that the contamination did not stem from leaking coal ash ponds as many feared. Instead, it came from natural sources; the interaction of volcanic rocks found across the Piedmont region. And it is more widespread than previously thought.

“About 90 percent of the wells we sampled had detectable levels of hexavalent chromium, and in many cases the contamination is well above recommended levels for safe drinking water. But our analysis clearly shows it is derived from natural sources, not coal ash,” said Avner Vengosh, professor of geochemistry and water quality from Duke’s Nicolas School of Environment.

“This doesn’t mean it poses less of a threat. If anything, because of contamination stems from water-rock interactions that are common across the Piedmont region, people in a much larger geographic area may be at risk. This is not limited only to wells near coal ash ponds.”

Hexavalent chromium is a potentially harmful chemical whose direct exposure can cause a number of adverse effects including asthma, cancer, liver and kidney damage but researchers are not sure whether its presence in drinking water could also have negative impact on health. 

To find whether coal ash is polluting N.C. wells, researchers collected groundwater samples from more than 300 drinking-water wells located both near and far from coal ash ponds across Piedmont region of North Carolina and tested each sample for Hexavalent chromium as well as a wide range of inorganic chemicals. Researchers found that the toxin was present not only in wells close to coal ash ponds but also miles away from the source (though, the levels could vary from each other), suggesting there must be another source involved in water contamination. Moreover, forensic geochemical technology also allowed researchers to trace containment back to its source.

“This, combined with the wide geographic distribution of samples containing elevated hexavalent chromium – regardless of proximity to a coal ash pond – points to the natural leaching of chromium from aquifer rocks in certain Piedmont geological formations.” Vengosh said.

About 90 percent of studied wells had detectable levels of naturally occurring Hexavalent chromium. Overall, hexavalent chromium was prevalent in groundwater across Piedmont region, which could be harmful for people drinking the contaminated water.

“The bottom line is that we need to protect the health of North Carolinians from the naturally occurring threat of hexavalent chromium, while also protecting them from harmful contaminants such as arsenic and selenium, which our previous research has shown to derive from leaking coal ash ponds,” Vengosh said. “The impact of leaking coal ash ponds on water resources is still a major environmental issue.”

 

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Hira Bashir covers daily affairs around the world.

 

 

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