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Coal Ash Spill Leads to Research Awards for ODU's Cutter, Sedwick

Professors Sedwick (left) and Cutter

Two Old Dominion University chemical oceanographers are among a select group of scientists who have been awarded a total of $2 million for environmental research related to the accidental spill in December 2008 of 5 million cubic yards of ash-laden sludge at the Tennessee Valley Authority (TVA) coal-fired generating plant in Kingston, Tenn.

Gregory Cutter, professor, and Peter Sedwick, associate professor, in ODU's Department of Ocean, Earth and Atmospheric Sciences, will lead two of six coal ash projects funded recently by the TVA and administered by Oak Ridge Associated Universities (ORAU). The ODU researchers' projects are designed to shed new light on dangers that arise when coal ash finds its way into natural waters, especially rivers.

Cutter is the principal investigator for the grant "Selenium Biogeochemistry in Rivers Receiving Direct Coal Ash Inputs." The award for the project is $275,228.

Sedwick leads the second project, with Cutter also as an investigator. Its title is "A New Approach to Quantifying the Release of Bioactive Trace Elements from Coal Combustion Products to Natural Waters" and the award for the work is $298,924.

Both projects commenced in May and will extend through April of 2013.

ORAU, a consortium of 98 major research institutions, including ODU, received 172 pre-proposals and 68 full grant proposals for the coal ash research initiative it announced last year. "With such heady competition, we were pleased to learn that Greg Cutter and Peter Sedwick received two of the six grants that were awarded," said Chris Platsoucas, dean of ODU's College of Sciences.

Investigators for the four other coal ash projects funded by the TVA are from Duke University, University of Kentucky, University of Illinois, University of Colorado, North Carolina State University, Iowa State University, Northwestern University and the U.S. Geological Survey.

While most of the research will probe the effects of the release of coal combustion products (CCPs) into the environment, some will also address ways to expand the beneficial uses of this waste material, for example, in concrete blocks.

The TVA's commissioning of the research follows the Dec. 22, 2008, failure of an earthen wall in the ash containment facility at the authority's generating plant in Kingston. CCPs had been mixed with water in order to be pumped out of the plant and were heavily concentrated in the mountain of sludge that flowed from the rupture. Some of this sludge spilled into the Emory and Clinch Rivers.

Cutter said much of previous coal ash research involving waters contaminated with selenium - potentially a very toxic chemical element - involved the element in the dissolved state and not the particulate form that got into the two Tennessee rivers. Furthermore, he said, most of these studies have targeted the lentic (still or slow moving) waters of lakes and reservoirs, rather than the lotic (swiftly moving) waters of rivers and streams.

For nearly a decade beginning in 1982, when Cutter joined ODU, he studied selenium cycling in cooling reservoirs associated with coal-fired power plants. The work was funded by grants totaling $500,000 from the Electric Power Research Institute.

"These reservoirs received effluents from fly ash (the very fine CCPs) settling ponds," he explained. "The fisheries in these lakes I studied in North Carolina and Texas had collapsed due to the inputs of dissolved selenium and arsenic from the fly ash waste water. The chemical forms of these elements made them very bioavailable and toxic."

The final part of this work resulted in Cutter (and David Burdige and Chester Grosch, two other ODU oceanography faculty members, along with the consulting company Tetra Tech) creating computer simulation models that allowed utilities to assess how fast their reservoirs would recover after they stopped putting fly ash effluent in them.

"So this new work for TVA is related, but has important differences," Cutter explained. "The input at Kingston was not dissolved selenium in wastewater, but rather direct ash input, or particles, and it was going into lotic waters, not lentic."

Selenium can have varying impacts on aquatic ecosystems, with toxicity depending on its chemical forms (species). Cutter will do research on-site at the rivers and in his laboratory on the ODU campus to determine the speciation of dissolved and particulate selenium in the moving waters. A specific goal will be to determine if the biogeochemical cycle of selenium in lotic waters is fundamentally different than in lentic waters, and how the cycle is affected by environmental variables such as temperature and oxygen concentrations in the water.

Cutter said particulate selenium can be expected to settle into river sediments and present a long-term source of contamination, but that little is known about the way toxic forms of the element will be released by the particulates, and how the release will be affected by the water flow across the sediments.

Sedwick, who joined ODU in 2008, has done research on how combustion aerosols such as coal fly ash deposit iron into oceans, and on factors affecting the bioavailability of the iron. "Greg and I have complementary expertise in, and equipment for, the analysis of trace elements in natural waters, and have known each other for over 20 years, so collaboration on this project was a natural," Sedwick said.

The research that Sedwick will lead proposes to use a new technique to assess the potential release of bioactive trace elements and nutrients from CCPs that get into natural waters. The suite of elements and nutrients he'll be testing for includes selenium, but also nitrogen, silicon, phosphorus, vanadium, chromium, manganese, iron, cobalt, copper, zinc, arsenic, cadmium, antimony, lead, mercury, thallium and uranium.

"I am new to research dealing directly with coal ash, but arrive at this from my recent work looking at atmospheric input of iron to the ocean, for which combustion aerosols such as coal fly ash appear to be important," Sedwick said. "For the new project, we will use a rapid, flow-through leaching technique that we and others have recently applied to assess the solubility of trace elements in aerosols."

He said this new method is well suited to the river analysis. Traditional batch-leaching methods typically are used to assess how groundwater and rainwater can release trace elements from CCPs buried in landfills.

The state-of-the-art analytical methods that Sedwick will apply include plasma-source mass spectrometry/optical spectroscopy, as well as highly sensitive flow analysis methods that he has used to detect trace metals in seawater.

Results of this project will advance our knowledge of the chemical impacts of any release of CCPs into natural waters. Also, the findings could be the basis of tests that determine if CCP-derived pollution is in water.

This article was posted on: July 9, 2010

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