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Among U.S. coal-fired power plants that monitor groundwater near their ash dumps, more than 90% have shown dangerous levels of toxic metals.

Environmental groups are pushing for tighter regulation and enforcement of EPA rules

A new study shows that of the 265 coal-burning power plants it studied in the United States, 241 have dangerous levels of toxic metals in the groundwater around them, based on Environmental Protection Agency (EPA) standards. The figure, which comes to 91% of the plants, was derived only from plants that must monitor the groundwater near their coal ash dumps. Coal ash is a byproduct of coal combustion stored on-site by power plants. The study was sponsored by a team of environmental groups spearheaded by the Environmental Integrity Project and Earthjustice. Lisa Evans, senior counsel for Earthjustice said:

Using industry’s own data, our report proves that coal plants are poisoning groundwater nearly everywhere they operate.

High Levels of Contaminants

For the study, data was gathered from 4,600 monitoring wells near coal ash dumps at approximately two-thirds of U.S. coal power plants.

According to 2018 data reported by power companies, the 10 most contaminated sites are in:

  • Texas: A site south of San Antonio was contaminated with 12 or more pollutants, including cadmium, as well as lithium at a concentration more than 100 times above a safe level.
  • North Carolina: Near Charlotte, thyroid-damaging cobalt and eight other contaminants are infiltrating groundwater at more than 500 times safe levels.
  • Wyoming: Lithium and selenium levels in groundwater have been observed at 100 times safe levels.
  • Wyoming: In southwest Wyoming, groundwater levels of lithium and selenium have been detected at 100 times safe levels, and arsenic has been detected at five times safe levels.
  • Pennsylvania: Northwest of Pittsburgh, arsenic in groundwater has been detected at levels 372 times higher than safe for drinking.
  • Tennessee: Southwest of Memphis, close to the Mississippi River, arsenic leaks into groundwater at 350 times safe levels, and lead infiltrates at four times safe levels. A direct connection has been discovered between the contaminated aquifer and the Memphis aquifer, threatening drinking water for thousands.
  • Maryland: Southeast of Washington, D.C., unsafe levels of eight or more pollutants have been measured, including lithium at more than 200 times the safe level, and kidney- and liver-damaging molybdenum at more than 100 times safe levels. The contaminated groundwater is also polluting local surface water.
  • Utah: To the south of Salt Lake City, groundwater has been contaminated with lithium at 228 times the safe limit, and cobalt at 26 times the safe limit.
  • Mississippi: To the north of Biloxi, groundwater has been contaminated with lithium at 193 times the safe level, molybdenum at 171 times the safe level, and arsenic at three times the safe level.
  • Kentucky: Northeast of Louisville, lithium has been detected in the groundwater at 154 times the safe level, and radium has been detected at 31 times the safe level.

A breakdown of the data also showed:

  • 52% percent of the plants had dangerous levels of the carcinogenic metalloid arsenic in adjacent groundwater.
  • 60% of the plants had dangerous levels of the neurotoxin lithium in adjacent groundwater.


Monitoring began under Obama administration regulations, but local testing of drinking water is not required. Regulations have relaxed for some plants, and cleanup of some ponds has been pushed back to the end of 2020. Environmental groups say it is time for tighter regulation and enforcement, but the EPA has not commented yet, pending review of the report.

Dealing With Contaminated Groundwater

Technologies available for arsenic and metal removal include coagulation filtration, oxidation filtration, adsorption with granular iron hydroxide media, ion exchange, membrane separation, and VSN-33 media. Choosing the best technology for removal of metals involves the many variables of the source water, requiring a treatment company with a deep reservoir of experience. Contact Fluence to learn about our sustainable solutions for heavy metal removal, or to discuss your next project with our experts.

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