Duke Energy's "naturally occurring" argument just went lame:
Tests show that the tracer can distinguish between the chemical signature of lead that comes from coal ash and lead that comes from other major human or natural sources, including legacy contamination from leaded gasoline and lead paint. "Lead adds to our forensic toolbox and gives us a powerful new method for tracking fly ash contamination in the environment," said Avner Vengosh, professor of geochemistry and water quality at Duke's Nicholas School of the Environment.
The tracer broadens scientists' ability to assess and monitor exposure risks of people who live or work near coal ash ponds and landfills or near sites where coal ash is being spread on soil as fill or reused for other purposes.
As I mentioned above, Duke Energy has played the "naturally occurring" card numerous times when individual toxic elements are discovered, and fossil fuel-friendly lawmakers have parroted those talking points ad nauseum during hearings and debates. I have often been frustrated with government regulators (state and federal) for not upping their scientific game to pierce that ambiguity. But in reality, they are simply not funded well enough to accomplish the R&D work and the regulatory work. Especially since the GOP took over the NC General Assembly and cut DENR's/DEQ's budget by over 40%. That research shortfall was not a coincidence, it was by design. Once again, we are blessed to have Avner and the Nicholas School working toward solutions:
Vengosh and his colleagues published their peer-reviewed study Oct. 16 in Environmental Science & Technology Letters. They analyzed 45 fly ash samples collected from 12 U.S. coal-fired power plants between 2004 and 2013. Sixteen samples of the fly ash originated from Appalachian coal, 22 came from coal in the Illinois Basin, and seven came from the Powder River Basin.
It is the first study to provide a systematic analysis of lead isotopes in coal fly ash from all three major U.S. coal-producing basins.
As a proof-of-concept experiment, the researchers used the new lead isotope tracer to analyze sediments from Sutton Lake in eastern North Carolina. The lake served as an impoundment for a coal-fired power plant from the 1970s until the plant was replaced with a natural gas-powered plant in 2013 and a study earlier this year by Vengosh's team showed that it was the site of multiple unreported coal ash spills over the years. Sutton Lake is located on the Cape Fear River about 11 miles upstream from the city of Wilmington. The researchers also tested sediment samples from nearby Lake Waccamaw, which has never been used as a coal ash impoundment.
"The tests showed the Sutton Lake sediments had a lead isotopic fingerprint similar to that of fly ash from Appalachian Basin coal and quite different from those of sediments in unaffected Lake Waccamaw," said Zhen Wang, a doctoral student in Vengosh's lab who was lead author on the study. "This was consistent with the results of the previous study, confirming our earlier findings and validating the applicability of lead isotopes as a new tool for tracking coal fly ask in the environment."
Drew Coleman (PhD) from UNC took part in this study from the geology angle, but apparently the NC Policy Collaboratory has no desire to collaborate with a world-class University just a few miles down the road. As a matter of fact, I see nothing even remotely connected to coal ash in the Collaboratory's recent projects/studies, which calls into question its entire existence, as far as I'm concerned. Many of my friends (mostly UNC folk) have said, "Let's not attack this until we see what they're going to do." Now I'm thinking a better question would have been, "What are they not going to do."