UPDATE: Dan River Shows High but Decreasing Arsenic Levels as Duke Energy Seals Broken Pipe Following Coal Ash Spill
Water quality tests conducted the week of February 3, 2014 by the North Carolina Department of Environment and Natural Resources (DENR) showed levels of arsenic, iron, copper and aluminum exceeding regulated limits.
The three metals (iron, copper and aluminum) all exceeded regulation limits in surface water. The tests showed that arsenic levels reached 40 micrograms per liter at the closest downstream point and 13 micrograms per liter at the Virginia state line February 3, then dropped to 6.3 and 10 micrograms per liter at the two sites February 4 when the samples were taken.
Arsenic is a well-known poison, which can cause skin legions, cancer and death in high concentrations. The U.S. Environmental Protection Agency standard for human health is 10 micrograms per liter and for aquatic life is 50 micrograms per liter. According to the EPA, however, water with arsenic levels near the 10 micrograms per liter limit would take years to cause those adverse effects, and the tests showed that the level of arsenic in the Dan is currently dropping down to and below the limit.
Downstream water authorities report that their water is still safe to drink, but the EPA’s limit is also meant to protect humans from non-drinking exposures as well as from drinking. DENR is advising local residents to avoid extended contact with the Dan River and the coal ash spill site.
More than a week has passed since a pipe burst beneath a coal ash pond in Rockingham County on February 2, flooding the Dan River with waste ash from a retired power plant. One of the major concerns in keeping the Dan River’s drinking water, which supplies towns like Virginia Beach and Danville, Va., safe is sealing the broken pipe to prevent more ash from entering the river.
Duke Energy officials say they succeeded in closing the leak on Saturday and are continuing to fortify the pipe to prevent further leaks. Duke Energy, which owns the plant, initially installed pumps and catch basins to decrease the flow to the river, but has now halted flow to the Dan River entirely.
DENR reported that 30 of the 34 contaminants they tested for fell within State and EPA regulations. Both Duke Energy and DENR will continue to monitor water quality both upstream and downstream from the coal ash spill.
- Daniel Lane
Daniel Lane covers science, medicine and the environment as a reporter/writer. He is currently pursuing a master's degree in medical and science journalism at UNC - Chapel Hill.
- Coal Ash Spill in the Dan River: DENR Still Testing for Coal Ash Metals (Feb. 6, 2014)
- Dan River Update: February 20, 2014