Study links coal ash to contaminated groundwater

The use of coal ash as fill material for roads, parking lots and buildings can be linked to contaminated groundwater in four southeastern Wisconsin counties.

This is the finding of a new study recently released by Clean Wisconsin, which has called for a moratorium on coal ash spreading until there is more research and regulation.

Don’t Drink the Water — said to be the first study showing the extent of molybdenum contamination in drinking water wells in southeastern Wisconsin and the first examining the reuse of coal ash waste for construction projects — arrived just before the U.S. Environmental Protection Agency is due to release a new regulatory rule. The rule, ordered by a consent decree in a lawsuit brought by a coalition of environmental groups represented by EarthJustice, is due on Dec. 19, after WiG went to press. The groups sued after the EPA’s work on the rule stalled, despite public outcry following a disaster in Tennessee in which a billion gallons of coal ash sludge destroyed 300 acres and dozens of homes.

Tyson Cook, CW’s director of science and research, said, “Toxic coal ash spills from landfills and retention ponds are not the only ways that coal ash can pollute the environment. It is also regularly placed under construction projects, often with no barrier between the ash and the groundwater.”

It’s the carpeting of southeastern Wisconsin with coal ash — the “beneficial reuse” of the material — that the Clean Wisconsin study focuses on in an attempt to determine how and why more than one in five wells in Waukesha, Milwaukee, Racine and Kenosha counties are contaminated with molybdenum above the state health advisory level.

Coal ash is an industrial byproduct — produced by coal-fired power plants — that contains toxic chemicals such as arsenic, boron, mercury, lead, hexavalent chromium and molybdenum. Producers may store coal ash on plant sites, but more often the waste is shipped to landfills or reused in construction. Wisconsin is recognized as a leader in the “beneficial use” of coal ash, a practice currently encouraged by the EPA.

Don’t Drink the Water identifies 1.6 million tons of coal ash used in more than 575 “beneficial use” projects in southeastern Wisconsin, projects in which coal ash was placed under roads, trails and buildings.

CW’s yearlong research built upon prior study and testing in the area conducted by the Wisconsin Department of Natural Resources, which reviewed elevated molybdenum levels in drinking water and focused on coal ash landfills in the Caledonia region. In 2013, the DNR said it could not identify a single source — like the We Energies Oak Creek plant — for the high levels.

This is where the CW study — which used data from the DNR — took off. “When the DNR was unable to point to the nearby coal ash landfills as the definitive sources of molybdenum contamination, it suggested that the molybdenum was likely either naturally occurring or coming from multiple anthropogenic sources,” the report says. “Since the evidence points away from natural sources being the cause, we conducted an analysis” to see if the contamination was associated with other man-made sources.”

The conclusion: “Wells closer to known coal ash reuse sites, particularly those larger than 500 tons, tended to have higher molybdenum levels than wells farther away.”

“Our research helps to fill some of the gaps and indicates a link between coal ash waste in the region and molybdenum contamination,” Cook said.

At Yorkville Elementary School in Racine, where bottled water is supplied and the DNR confirmed contamination in 2013, molybdenum levels were tested and found to be as high as 138 parts per billion — 70 percent higher than the one-day exposure level that the EPA says is safe for kids. In 2000, according to DNR records, some 856 tons of coal ash were used as fill in the school parking lot.

A second school, North Cape Elementary, is supplying bottled water and testing has shown elevated levels of molybdenum. About 191 tons of other ash were used to stabilize the soil at a construction project there in 2007 and about 654 tons of coal ash were employed in 2005 in a project about a half-mile from the school.

DNR critical

Don’t Drink the Water drew criticism from the DNR, which said the researchers did not “legitimately explore the potential for the natural occurrence of molybdenum” and the report did a poor job of looking at the types of coal ash and distinguishing the different uses. When it is used in concrete, asphalt and wallboard, coal ash doesn’t leach into groundwater, and that’s how about 90 percent of the material has been used in the region.

A statement from the DNR said, “The department does not concur that there is a clear correlation between the elevated molybdenum in groundwater in southeast Wisconsin and the beneficial use of ash from coal fired power plants. 

“As Clean Wisconsin acknowledged in their report, it is challenging to determine the sources or causes of elevated molybdenum in groundwater in southeast Wisconsin.”

The DNR said, “The sources may be human caused and/or naturally occurring, but the data currently available are inconclusive.”

Both the DNR and Clean Wisconsin said more research is needed.

“Much more evaluation is required,” the study states. “While we can’t definitively point to a sole cause of the molybdenum contamination in southeastern Wisconsin, the analysis … provides strong evidence that the coal ash spread throughout the region was at the very least contributing to the drinking water contamination.”

The findings led those involved in the project to issue a series of recommendations, including the call for a moratorium.

“We need to halt the use of coal ash where toxins can leach into groundwater, put better protections in place and clean up the drinking water in southeastern Wisconsin,” said Clean Wisconsin general counsel Katie Nekola.

She said the report supports a call for more testing of groundwater in areas where coal ash was placed, requiring more testing of coal ash, establishing reporting requirements for the use of coal ash and enacting a moratorium on the reuse of coal ash until new safeguards are in place.

Some regulation may come from the federal government.

The rule, following a White House review, is due from the EPA this month and could address whether to label coal ash as “hazardous” waste. “A strong federal coal ash rule could help ensure safe drinking water not only in Wisconsin but across the nation,” said Nekola.

Ann Coakley, the DNR’s Waste and Materials Management Program director, said after the EPA issues its plan the DNR will “compare the new law to our existing state framework in the weeks and months that follow.”

We Energies spokesman Brian Manthey said the utility believes “the current DNR rules concerning coal ash landfills and beneficial use rules are appropriate regulations for the protection of human health and the environment” and no moratorium is needed. 

He added, “The EPA encourages the beneficial use of coal ash, citing positive environmental, economic and performance benefits.”