Friday, December 19, 2014

Chatham County opposes Duke's ash disposal

Chatham County commissioners cited "substantial health and environmental risks" this week in opposing Duke Energy's plan to dump coal ash into open-pit clay mines.

Commissioners adopted a resolution against Duke's plan, announced last month, to send 2.9 million tons of ash to mines in Chatham and Lee counties.

Lee County officials have said they want the county to be compensated for taking the waste, likening it to host fees typically paid for regional solid waste landfills.

The Chatham resolution says the plan would expose residents to risks from potentially toxic elements in ash. It identifies "shortcomings" in the legislation this year that ordered Duke to close its 32 ash ponds, including lack of local control over ash disposal and fees.
Duke has said it needs to move quickly to meet deadlines set out in the legislation. The initial phase of work would move ash from four power plants, including Riverbend west of Charlotte, starting early next year.

Tuesday, December 16, 2014

Duke scientists develop coal ash tracers

Duke University researchers said Tuesday they have developed a new tool to tell when water is contaminated by coal ash and not by other sources.

Regulators will be able to "trace the coal ash effluents to their source," Avner Vengosh, a Duke professor of geochemistry and water quality, said in a statement.

The research is timely for North Carolina, where contaminated groundwater has been found at all 14 of Duke Energy's coal-fired power plants and seepage reported from ash pond dams. What hasn't been clear is whether the contamination came from ash or natural sources.

Duke, under the legislature's orders, is drilling hundreds of new wells at its plants to detect the extent, flow and sources of contaminated groundwater.

Chemical variations have previously been used to identify ash contaminants. The forensic tracers Duke University developed are based on the distinctive characteristics of two elements found in ash, boron and strontium.

The isotopes in boron that come from coal ash always differ from naturally-occurring boron, said Laura Ruhl, a former Duke graduate student now teaching at the University of Arkansas at Little Rock. Strontium is less distinct, she said, but using the two elements together provides "definitive evidence" whether contamination is from ash.

Vengosh and Ruhl published their findings this week in the peer-reviewed journal Environmental Science & Technology. Co-authors included Gary Dwyer and Heileen Hsu-Kim of Duke and James Hower of the University of Kentucky.

Monday, December 1, 2014

Dan River bottom life is thriving, DENR says

North Carolina's environmental agency says bugs "appear to be thriving" at the bottom of the Dan River downstream of Duke Energy's February coal ash spill.

Department of Environment and Natural Resources staff sampled upriver and about two miles downriver of the spill on Oct. 28. It was DENR's first testing of the aquatic insects, worms and other invertebrates at the base of the food chain. Their numbers, type and diversity signal a river's overall health.

Findings were similar in both places and had the highest biological rating, the department said.

Tests of water quality, river sediment and fish tissue are continuing. The results will be factored into a natural resource damage assessment that state and federal agencies are conducting.

Biologists have said that river-bottom creatures were likely smothered by up to 39,000 tons of ash that Duke's Dan River power plant dumped into 70 miles of river.

Operations to suck up the deposits got only 3,000 tons of ash and sediment. Duke and the Environmental Protection Agency said trying to retrieve all the ash would do more ecological harm than leaving it in place.