- Last Updated on 07:39 AM 02/19/14
- BY Special to The Gazette
The U.S. Fish and Wildlife Service is continuing to provide fish and wildlife expertise during the emergency response and remedial phases following the Dan River coal ash spill and will work with others to determine the impacts of the spill, short-term and longer-term, on fish, wildlife and their habitat.
“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 5 feet of ash or ash/sand mix over the natural stream bottom. Our biologists are working with the U.S. Environmental Protection Agency and Duke Energy biologists on a downstream reconnaissance; we’ve found ash covering natural sediment over five inches thick atop sand bars within two miles of the spill site, and two inches thick to the North Carolina/Virginia line about nine miles downstream. Further downstream as far as South Boston, we’ve observed one-eighth to one-half inch of ash on sandbars and other depositional areas and traces of ash all the way to Kerr Lake.
“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.
Teams will need to assess conditions at the stream substrate where some of the sensitive resources reside, especially in areas where the ash accumulates.
The Fish and Wildlife Service has had field crews on the water. Just after the spill, the water was extremely cloudy, so observations were restricted to the water’s surface and river banks. Service personnel have not directly observed any sick or dead fish or wildlife, according to Augspurger.
A few citizens reported seeing dead turtles at two Virginia parks, and biologists visited both of those sites but didn’t find any carcasses. Wildlife morbidity and mortality reports can be made to the Fish and Wildlife Service contacts or at EPA’s website for this event at http://www.epa.gov/region4/duke-energy/contact.html).
Looking at the surface water quality data collected by others, biologists noted exceedences of the North Carolina state water quality standard for turbidity (a measure of light scattering which indicates how clear or cloudy the water is) in most samples downstream of the spill during the first four days after the release.
There were a few exceedences of arsenic and selenium standards for protection of aquatic life and frequent exceedences of the state action level for copper in water, but their connection to the spill is not certain, he added.
The Fish and Wildlife Service teams were able to assess shoreline and sandbars between the site of the release and Kerr Lake, although some sections in that stretch remain to be surveyed this week.
It is not yet known if the ash deposits stay in place after higher river flows, such as the recent increased flows from snow melt. More detailed assessments will follow when the emergency response phase is over, Augspurger said.
The Fish and Wildlife Service has coordinated with state and federal biologists in North Carolina and Virginia to synthesize information on the locations of rare species and other resources at risk.
“We have coordinated with biologists and toxicologists familiar with coal ash to focus response and assessment efforts. Some of that includes suggestions for sample collection methods to examine potential habitat impacts (e.g., sediment sampling, sampling throughout the water column in addition to the surface) – sampling now in progress,” he added.
In addition to the field reconnaissance, Fish and Wildlife Service specialists have worked with the incident command on emergency endangered species consultations – expediting any response actions proposed by Duke Energy and USEPA, and they have begun impact assessment discussions with Duke Energy and others.
The Fish and Wildlife Service’s initial concern is the physical burying of habitat that is important for fish, mussels and other aquatic life. The ash can coat the bottom in depositional areas, burying animals and their food. The service also is concerned about physical effects on gill tissues in fish and mussels from exposure to coal ash. There also may be longer-term toxicological impacts to aquatic animals from metals of elevated concentrations in ash, Augspurger added.
The Fish and Wildlife Service is a supporting agency to the U.S. Environmental Protection Agency Federal On-Scene Coordinator providing technical assistance, primarily regarding natural resources at risk.
In the incident command structure for this event, the Fish and Wildlife Service is working most closely with the Environmental Unit and have had contaminants specialists, endangered species biologists and GIS/mapping experts on site to help in the response efforts.
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, Augspurger explained.
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 of our native freshwater mussels, the James spinymussel requires certain species of fish to reproduce,” he said.
The female mussel releases larval mussels, called glochidia, into the water column. The glochidia must come in contact with specific species of fish, and if they encounter these species they attach to the fishes’ gills and draw nourishment from the fish.
After developing into juvenile mussels, they detach from the fish and drift to the stream bottom where they will develop into adults if they land in a suitable substrate. Survival of the James spinymussel is linked to the habitat and environmental quality requirements of its host fish species.
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,” Augspurger added.
On the web: http://www.fws.gov/southeast/pubs/facts/DanRiverCoalAshReleaseFacts.pdf