Technologies that cut harmful emissions from power plants have increased the risk of downstream water contamination, according to a Duke University-led study published in the peer-reviewed journal Environment Science & Technology.
Researchers, who collected and analyzed more than 300 water samples from 11 North Carolina lakes and rivers for the study, found high levels of arsenic, selenium and other toxic elements in coal ask effluents downstream from the settling ponds of coal-fired power plants. The study, “The Impact of Coal Combustion Residue Effluent on Water Resources: A North Carolin Example” was funded by the North Carolina Water Resources Research Institute.
The study found that while scrubbers and other installed technologies have removed particulates from power plant emissions, those contaminants have ended up in the solid waste residue and wastewater produced by the facilities. Plants that used flue gas desulfurization often discharged wastewater with greater concentrations of selenium and other contaminants, said Laura Ruhl, the lead author of the study.
Some of the highest levels of contaminants were found in coal ash pond effluents flowing to Mountain Island Lake, a primary drinking water source for Charlotte, North Carolina. The study also found high contaminant levels in Hyco and Mayo lakes, two popular recreation lakes in the northern part of the state.
In several cases, the researchers found contamination levels that far exceeded EPA guidelines for safe drinking water and aquatic life, said Avner Vengosh, professor of geochemistry and water quality at Duke University’s Nicholas School of the Environment.
A report released earlier this month by the Electric Power Research Institute warned that current and pending EPA power plant regulations could cost the US economy up to $275 billion between 2010 and 2035 if the regulatory timeline is followed.
The findings were part of the EPRI’s “The Value of Innovation in Environmental Controls,” an expanded strategic analysis of key technology, market and policy uncertainties confronting the existing US coal-based generation fleet over the next few decades, including proposed regulations and the long-term price of natural gas.
Coal-based power plants must comply with the EPA’s Mercury and Air Toxics Standards by 2015. The EPA also has proposed regulations that would reduce the amount of water used to cool generating facilities, and regulate how coal ash is stored.