More than half the drinking water wells tested in Chatham County contained levels of contaminants associated with coal ash that were above the state’s health advisory goal, according to researchers from UNC and Virginia Tech.
Earlier this spring, researchers tested water from 242 private wells; 51 percent had elevated levels of Chromium 6 and 84 percent had high levels of vanadium. The state health goal for Chromium 6, also known as hexavalent chromium, is 0.07 parts per billion. Among the wells tested, the average concentration for Chromium 6 was 0.14 ppb — twice the health goal –and the maximum detected reached 3.25 ppb.
The Centers for Disease Control and Prevention has linked Chromium 6 to cancer, respiratory illness, and liver and kidney disorders.
For vanadium, the state has set an interim standard of 0.3 parts per billion. The average among the tested wells was 1.4 ppb — five times the health goal — and the maxiumum was 20.8 ppb.
Exposure to vanadium can result in anemia, neurological effects and high blood pressure.
Researchers released the sampling results Friday evening at a community meeting in Moncure.
Chromium 6 and vanadium are found in coal ash, but they are also naturally occurring. Moncure has a nearly 100-year history with and coal ash and Duke Energy. The utility operated the Cape Fear coal-fired power plant in Moncure from 1923 to 2011; the plant has been demolished.
However, Duke recently received an air permit from the Department of Environmental Quality for a beneficiation plant at the Cape Fear site to convert fly ash for use in cement. Although the facility will have pollution controls, it still will emit thousands of pounds of arsenic, beryllium, cadmium, sulfuric acid and other hazardous and toxic chemicals into the air each year.
The utility also stores coal ash from its Sutton plant in Wilmington in a lined impoundment at the Brickhaven Mine, also in Moncure.
Researchers are now mapping the wells and their proximity to potential pollution sources.
About 10 percent of the wells contained high levels of lead, including one with 1,326 parts per billion. Although there is no safe level for lead, the EPA has set a maximum contaminant level of 15 ppb. High lead levels can be caused by old household plumbing.
Similarly, elevated copper concentrations, which affected about 36 wells, can be the result of pipes. When water is naturally acidic, it can eat away at the copper, which in turn leaches into the drinking water.
Researchers tested 786 wells in Iredell County, where Duke operates the Marshall Steam plant on the shores of Lake Norman. Seventy-nine percent of which had levels of Chromium 6 above the health advisory goal. Of 62 Robeson County wells, 23 percent had elevated levels of the compound. Duke Energy operated the Weatherspoon plan in Lumberton until 2011.
UNC researcher Andrew George will present the Chatham County findings at a second community meeting, Tuesday from 6 to 7 p.m. at Central Carolina Community College, Multipurpose Room, Building 42, 764 West St., Pittsboro.