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Coal waste deposits turn up 70 miles from spill
SoVaNow.com / February 20, 2014
Coal ash deposits have been detected in the Dan River as far as 70 miles downstream from the site of the Feb. 2 coal ash spill in Eden, N.C., raising concerns about the impact on aquatic life in the river and Kerr Reservoir.
In South Boston, the U.S. Fish and Wildlife Service has found concentrations of ash of one-half to one-eighth of an inch on sandbars and other deposit sites, according to an advisory issued Tuesday by the federal agency.
Near the decommissioned Dan River Steam Station in Eden, Fish and Wildlife staffers have found ash mixed with sand up to five feet deep. At the Virginia-North Carolina state line, nine miles from the site between Eden and Danville, samples detected ash two inches thick.
Traces of the toxic wastes also have turned up in Kerr Lake.
"Biologists and environmental contaminants specialists from our North Carolina and Virginia field offices have initially found layers of coal ash of varying thickness spread out over 70 miles of the Dan River," said Tom Augspurger, Contaminants Specialist for the U.S. Fish and Wildlife Service. "At the spill site, we identified a coal ash bar about 75 feet long and 15 feet wide which had as much as five feet of ash or ash/sand mix over the natural stream bottom.”
Wildlife officials say they are concerned about the potential long-term impact of the spill on fish, mussels and other aquatic life in the river basin, especially small invertebrates that live in sediments and comprise a key part of the aquatic habitat.
The coal ash is burying riverbed animals and clams, worms and crustaceans that make up the food chain for fish, birds and other animals along the river, officials say, and they further worry that coal wastes may clog gill tissues in fish and mussels.
"The deposits vary with the river characteristics, but the short and long term physical and chemical impacts from the ash will need to be investigated more thoroughly, especially with regard to mussels and fish associated with the stream bottom and wildlife that feed on benthic invertebrates," said Augspurger. Benthic invertebrates are organisms that live in or on the bottom sediments of rivers, streams, and lakes.
Federal wildlife biologists and staff also are investigating reports of dead aquatic turtles at two Virginia state parks on the river basin, although the turtle deaths have not been confirmed, nor has a firm connection been made to the disaster.
The coal ashes escaped Feb. 2 from a collapsed waste lagoon at the Dan River Steam Station in Eden, N.C., where an estimated 39,000 tons of coal ash spilled out into the river through a broken drain pipe. Duke Energy, owners of the decommissioned coal-fired plant, initially estimated that 82,000 tons of ash escaped into the Dan; it has since revised that estimate downward.
Prior to the coal ash spill, the Dan and Kerr Lake were subject to advisories warning people not to consume more than two fish per year from the waterways, due to mercury and PCB contamination in fish tissue.
In addition to common aquatic species, there are two federally listed endangered species, the Roanoke logperch (Percina rex) and the James spinymussel (Pleurobema collina) in the Dan River system in North Carolina and Virginia. The Dan River system supports another freshwater mussel species, the green floater (Lasmigona subviridis), which the Service is currently evaluating to determine if it warrants protection under the federal Endangered Species Act.
Records for all three of these species are found either upstream or downstream of the area affected by the Dan River Steam Station coal ash spill.
The Roanoke logperch is a relatively small fish, attaining a length of 5 to 5.5 inches. It lives on the stream bottom and finds insect larvae for food by flipping over stones with its snout. Because of this feeding behavior, this fish relies on loosely embedded, silt-free, gravelly stream substrates. It is found in the Chowan River basin in Virginia and the Roanoke River basin in Virginia and North Carolina.
The James spinymussel is one of only three species of freshwater mussels in the U.S. that has spines on its shell. An adult is about three inches in length. It feeds on bacteria, algae, and other small food items which it filters from the water column, thereby helping to clean the stream water. Like most native freshwater mussels, the James spinymussel requires certain species of fish to reproduce.
“Survival of the James spinymussel is linked to the habitat and environmental quality requirements of its host fish species,” the Service stated in its advisory.
“The James spinymussel is typically found in coarse sand and small gravel substrates, often interspersed between cobble and boulders, which help provide a hydraulic refuge. Like the Roanoke logperch, the James spinymussel does not do well in silty substrates. It is found in the Dan River basin in North Carolina and Virginia, and the upper James River basin in Virginia and West Virginia.
“Like the James spinymussel, the green floater is a relatively small mussel species, reaching around 2.5 inches in length. It also is typically found in relatively silt free, sandy, gravelly substrates. Unlike the majority of our native freshwater mussels, there is some evidence that the green floater may not require a fish host to reproduce. It is currently known from scattered locations from the Hudson River system, New York, to the Savannah River system in South Carolina.”
Still unknown, noted the Service, is whether the ash deposits will stay in place after higher river flows, such as from this week’s snow melt. More detailed assessments will follow when the emergency response phase is over, the agency noted.
Government officials continued to assure area residents that drinking water drawn from the Dan River and Kerr Reservoir is safe. While raw water samples have turned up concentrations of some heavy metals such as iron, aluminum and copper that exceed federal clean water standards, testing of treated tap water has shown that municipal systems are successful in filtering out the contaminants.
On the web: http://www.fws.gov/southeast/pubs/facts/DanRiverCoalAshReleaseFacts.pdf
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