Duke Energy Corp. is still battling to halt a leak from a coal-ash pond into the Dan River in North Carolina, in the latest incident to draw attention to how power-plant waste is regulated.
The spill contained toxic levels of arsenic, chromium, lead and other heavy metals common in coal based on a samples taken Feb. 4, Waterkeeper Alliance, an environmental group, said today in a statement. Duke said downstream drinking water supplies are safe, based on samples at intakes and of treated water.
The spill comes as the U.S. Environmental Protection Agency prepares to issue regulations for coal ash after a record 1 billion gallons of ash sludge poured into Tennessee’s Emory River from a Tennessee Valley Authority disposal pond in 2008. Duke estimated its Dan River Plant pond has leaked as many as 27 million gallons of water and 82,000 tons of ash since Feb. 2.
A certified laboratory analysis of the spill itself found an arsenic level of 349 parts per billion, enough to be acutely toxic to fish and 35 times higher than the limit for drinking water, Donna Lisenby, Waterkeeper Alliance’s global coal campaign coordinator, said today in a phone interview.
The arsenic concentration dropped to 6 parts per billion in a sample she took two miles downstream, she said.
Levels of arsenic, lead and selenium were 2 parts per billion, the lowest detectable amount, at downstream drinking water intakes in samples taken Tuesday, Duke said a statement last night.
Duke’s priority is to stop the leak, Meghan Musgrave, a spokeswoman for the largest U.S. utility owner in Charlotte, said yesterday in a telephone interview. The rate of spillage declined Feb. 4 after the pond emptied and has fluctuated since then because of rain and repairs, Musgrave said. Duke estimates that the pond contained 992,000 tons of ash and that about 10 percent has spilled, she said.
Overnight crews dug down to a broken storm-water pipe that runs under the pond, through which water and ash flowed to the river, and will attempt to plug it, said Lisa Hoffman, another spokeswoman for Duke. The company’s efforts to stop the leak were criticized by environmental groups.
“Duke has done nothing to contain the spill,” Lisenby said. When Lisenby visited the spill location Feb. 4, “there were no hard assets deployed on the river to clean up the ash, contain the ash, or stop the spill,” she said.
The ash originated at Duke’s Dan River Steam Station, closed since 2012 as the company replaced coal-fueled plants with those that run on cleaner-burning natural gas in anticipation of tighter air pollution rules. The TVA spill also came from a pond at a retired coal plant.
No arsenic or other heavy metals were found in the first samples of treated river water taken at Danville, Virginia, Arnold Hendrix, a spokesman for the city, said yesterday in a telephone interview. Danville is located 25 miles (40 kilometers) downriver from the spill site. The Dan provides Danville’s water supply.
Danville had earlier said its water treatment plant was successfully removing bits of ash that had turned water from the river gray.
The first samples of treated river water were collected by Duke and the results announced by the city in a statement. Danville also has collected its own samples and sent them for analysis, Barry Dunkley, the local division director of water and wastewater treatment, said in a Feb. 4 telephone interview.
River water at the site tested normal for temperature, acidity and dissolved oxygen, indicators that are important to fish, the North Carolina Department of Environment and Natural Resources said in a statement. Test results for heavy metals are expected today.
“Those who get their drinking water from private or community wells will be unaffected by this event,” John Skvarla, the department secretary, said in the statement. “Water from the river that has been treated by nearby municipal treatment facilities is safe to drink.”
As many as 190 coal-fired generators are set to be shut by 2022, mostly because of increased regulations and competition from shale gas, according to the Edison Electric Institute, the trade group for investor-owned utilities.
Environmental groups have sued the EPA to force a decision on coal-ash regulations, arguing that new rules are needed to protect human health and the environment. The EPA told a judge last month it will publish a final rule for managing coal-plant waste by Dec. 19.
Duke agreed last year to pay $100,000 to settle North Carolina claims that ash ponds at two of its coal-fired plants had polluted groundwater, according to a filing with the U.S. Securities and Exchange Commission.
The company said previously it’s working with North Carolina officials on a plan for ash sites at closed plants.