State continues testing fish for toxins in Dan River
The state continues to test fish for toxins years after the coal ash spill in the Dan River.
Environmentalists say now is when many issues may start to arise.
It's been about two-and-a-half years since the coal ash spilled into the Dan River.
Environmentalists say it takes two years for a toxin called selenium to show up in fish tissue.
North Carolina and Virginia DEQ have sampled the river yearly, since 2014.
The results have not shown any abnormally high levels of the toxin, which can impact breeding.
We spoke with the Dan River Basin Association over the phone Thursday.
The group is concerned it's taking too long to get the results of this testing and they want to see a long-term plan moving forward.
Duke Energy, the company responsible for the spill and the cleanup, says it will test until 2017 and will re-evaluate if the levels change
"We want to be able to paint an accurate picture of what we are seeing in the river and state regulators as well are doing the same thing,” said Jeff Brooks of Duke Energy. “So together, when we look at all that data together at least through the first part of this year we have not seen any indications of threats to the fish or the indications to their tissue and that's a good thing."
The Virginia Department of Environmental Quality is scheduled to begin its 2016 testing within the next couple of weeks.
Duke Energy says its 2016 samples will be available late this year or early 2017.
Tests from previous years show low levels of selenium in the fish tissue
Virginia DEQ leaders and environmentalists both agree that we're now entering the timeframe when changes might start to show up.
We can not come to any definitive conclusions based on the limited amount of data presented by his preliminary report. We suggest and independent review of the findings and continued monitoring and research. The only real data to compare to is the Kingston Coal ash spill in the Clinch river watershed.
There are significant differences between the TVA and Dan River events, but there also are similarities.
In the TVA incident, ash recovery and ecosystem and human health assessments were conducted over a five-year period with long-term monitoring to continue for 30 years at five-year intervals. Although the TVA spill was much larger than the Dan River Spill, they estimated that 90% of the material was recovered while only 7-8% of material was recovered from the Dan. This difference could be a significant factor in ecological recovery.
The question can be stated: Do levels of ash-related constituents in sediment or diet (benthic invertebrates) continue to pose sufficient risk to ecological receptors to warrant additional management actions? Remediation goal and tissue monitoring endpoints should be selected to be protective of the ecological receptors.
We do not feel like 2-3 years of data is sufficient to determine if ash-related constituents will exceed the RGs in sediment or the TMEs in benthic invertebrates, particularly as the sediments move downstream to Lake Kerr. Trends may indicate a natural attenuation processes, e.g., mixing of ash and sediment, diminishing bio-uptake, but that is something that still needs to be determined.
In the TVA spill in Kingston they also analyzed and monitored riparian area species that could be affected in the food web including aerial feeding insectivores and birds. The monitoring plan included supplemental long term fish tissue monitoring for bio-accumulation, fish health and reproduction, preliminary assessment reports and formal 5 year reviews to evaluate trends and document results for up to 30 years.
Coal combustion residues(CCRs) contain high concentrations of heavy metals. Recent structural failures of on-site containment ponds and leaching of CCRs has potentially endangered the health of adjacent water bodies. Studies are currently underway to examine the influence of CCR enrichment of river sediments through the study of mercury, an abundant constituent of CCRs, and the concomitant production of methylmercury. The CCR contamination may increase the exposure to mercury for aquatic life through leaching and re-suspension mechanisms. University of Maryland research on the Dan river sediments found that CCR particles and the mercury they contain are present primarily in the silt and clay fractions of sediment and there is a direct relationship between CCR concentrations and total mercury concentrations. These findings have implications for both the bioavailability of mercury to methylating bacteria, higher organisms prone to direct ingestion of fine particles.
Long term studies of the ecosystem downstream should considered in a plan as well as sediment transport models and ecological risk assessment to support an adaptive management recovery plan. There is no "smoking gun" in the 2 year fish tissue sampling reports but further study is warranted due to our lack of knowledge of transport trends and what may happen as the ash reaches the anaerobic sediment environment of Lake Kerr. We know ground water leaching has been contaminating the downstream environment for years and the spill increased the exponentially.
Although some risk assessment studies conducted for the TVA spill identified no unacceptable risks to humans or biota who consume fish, nor unacceptable risks to the fish community, the research is on-going, and the TVA ash spill recovery from the system was greater comparability with what is left in the Dan River. Fish tissue sampling is just one of the methods that should be utilized to continue to evaluate recovery of the ecological function and recreational use of the river system, and downstream communities such as Lake Kerr.