Tests Reveal Leaching from Coal Ash Sites

Date: June 14, 2016

Source: News Room

Duke University scientists announced that coal ash ponds at 21 power plants in five states are leaching contaminants into surrounding water which they published in the journal Environmental Science & Technology. Toxic metals such as arsenic and selenium, which occur in ash, were found in water near ash ponds at all 21 power plants in the study. "With over 500 coal ash ponds in the southeastern U.S., the results presented in this study suggest significant releases of coal ash-impacted water to the environment," the study concludes. The study does not determine whether any contaminants have reached communities near the power plants. The Southern Environmental Law Center, a nonprofit business that represents advocates in lawsuits against Duke Energy and other utilities over ash contamination, financed the study.

Coal-fired power plants generate about 140 million tons of fly ash, scrubber sludge, and other combustion wastes every year. Coal combustion waste sites are known to have contaminated groundwater, wetlands, creeks, or rivers. In December 2014 the US EPA finalized national regulations to provide a comprehensive set of requirements for the safe disposal of coal combustion residuals (CCRs), commonly known as coal ash, from coal-fired power plants. The rule establishes technical requirements for CCR landfills and surface impoundments under subtitle D of the Resource Conservation and Recovery Act (RCRA).


Evidence for Coal Ash Ponds Leaking in the Southeastern United States

Jennifer S. Harkness†, Barry Sulkin‡, and Avner Vengosh*†
† Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, North Carolina 27708, United States
‡ Environmental Consultant, Nashville, Tennessee, 37218, United States
Environ. Sci. Technol., Article ASAP
DOI: 10.1021/acs.est.6b01727
Publication Date (Web): June 10, 2016
Copyright © 2016 American Chemical Society
E-mail: vengosh@duke.edu; phone: 919-681-8050; fax: 919-684-5833.


Coal combustion residuals (CCRs), the largest industrial waste in the United States, are mainly stored in surface impoundments and landfills. Here, we examine the geochemistry of seeps and surface water from seven sites and shallow groundwater from 15 sites in five states (Tennessee, Kentucky, Georgia, Virginia, and North Carolina) to evaluate possible leaking from coal ash ponds. The assessment for groundwater impacts at the 14 sites in North Carolina was based on state-archived monitoring well data. Boron and strontium exceeded background values of 100 and 150 µg/L, respectively, at all sites, and the high concentrations were associated with low d11B (-9‰ to +8‰) and radiogenic 87Sr/86Sr (0.7070 to 0.7120) isotopic fingerprints that are characteristic of coal ash at all but one site. Concentrations of CCR contaminants, including SO4, Ca, Mn, Fe, Se, As, Mo, and V above background levels, were also identified at all sites, but contamination levels above drinking water and ecological standards were observed in 10 out of 24 samples of impacted surface water. Out of 165 monitoring wells, 65 were impacted with high B levels and 49 had high CCR-contaminant levels. Distinct isotope fingerprints, combined with elevated levels of CCR tracers, provide strong evidence for the leaking of coal ash ponds to adjacent surface water and shallow groundwater. Given the large number of coal ash impoundments throughout the United States, the systematic evidence for leaking of coal ash ponds shown in this study highlights potential environmental risks from unlined coal ash ponds.

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