Long-lasting contamination won't be cleaned up by ash removal alone
A Duke University study of coal ash ponds near 21 power plants in five Southeastern U.S. states has found evidence that nearby surface waters and groundwater are consistently and lastingly contaminated by the unlined ponds.
A study of power plants in five states has found that metals and other toxic materials are able to leach out of the unlined pits in which coal ash is currently stored. These materials have been found in surface waters and shallow groundwater, and may be able to work their way to the deeper groundwater resources used for drinking water wells.
Credit: Duke University
High levels of toxic heavy metals including arsenic and selenium were found in surface waters or groundwater at all of the sites tested. Concentrations of trace elements in 29 percent of the surface water samples exceeded EPA standards for drinking water and aquatic life.
"In all the investigated sites, we saw evidence of leaking," said Avner Vengosh, a professor of geochemistry and water quality in Duke University's Nicholas School of the Environment. "Some of the impacted water had high levels of contaminants."
The study, which appears June 10 in the journal Environmental Science & Technology, did not test drinking water wells, but that will be the next phase of the research, Vengosh said.
During the summer and fall of 2015, the team sampled 39 surface water and seep samples from coal ash ponds at seven sites. They also analyzed water chemistry data from 156 shallow groundwater monitoring wells near coal ash ponds at 14 North Carolina power plants that had been compiled by the state's Department of Environmental Quality.
Shallow wells -- typically 30- to 50-feet deep -- are not as deep as a drinking water well, which might be 100 to 300 feet. But there's a potential the shallower contamination could flow deeper and affect drinking wells, Vengosh said.
Not only was the evidence of contamination widespread, it also appears to be persistent in the environment. Some of the sites studied have been retired and no new coal ash is being deposited there, but nearby surface waters, and in one case groundwater, were still being contaminated.
"The degree to which leakage affects the concentration of toxins in nearby waters varies because of several factors, including the nature of the coal ash, processes in the pond and the flow through the local soil," said Jennie Harkness, a Ph.D. student at the Nicholas School and the lead author of this study.
While it is legally permitted for some coal ash ponds to release liquid effluents to nearby surface waters through regulated outfalls, the new data show that these ponds are also leaking in unpermitted ways. "Coal ash ponds pose risks to the environment and water resources," Vengosh said.
The highest concentrations of dissolved metals and metalloids (manganese, vanadium, selenium, arsenic and molybdenum) were found in shallow wells near a retired ash-disposal site in Tennessee. The contaminated groundwater there had concentrations exceeding drinking water and aquatic life standards for cadmium, iron, nickel, lead, selenium and zinc.
Vengosh said it is reasonable to conclude from these findings that physically removing the coal ash ponds would leave "a legacy of contamination. You would still have a major issue to address the subsurface groundwater contamination. After decades of leaking, the impact has already happened."
Funding for this study was provided by the Southern Environmental Law Center.
CITATION: "Evidence for Coal Ash Ponds Leaking in Southeastern United States," Jennifer Harkness, Barry Sulkin and Avner Vengosh. Environmental Science and Technology, online June 10, 2016. DOI: 10.1021/acs.est.6b01727
Karl Leif Bates | EurekAlert!
Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute
Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
07.12.2016 | Health and Medicine
07.12.2016 | Life Sciences
07.12.2016 | Health and Medicine