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Water fountains are taped over at Yorkville Elementary School in Racine County due to high levels of the metal molybdenum. The environmental group Clean Wisconsin alleges that coal ash buried in a school construction site is partly to blame.
Water fountains are taped over at Yorkville Elementary School in Racine County due to high levels of the metal molybdenum. The environmental group Clean Wisconsin alleges that coal ash buried in a school construction site is partly to blame. Cole Monka / Wisconsin Center for Investigative Journalism

Hundreds of private wells in southeastern Wisconsin are so polluted that their owners cannot drink the water because of high levels of molybdenum. Now, an environmental advocacy group reports a link between the contaminated wells and building and road construction sites where We Energies disposed of coal ash, which contains the metal.

In a study released Tuesday, Clean Wisconsin connected high levels of molybdenum to the nearby presence of ash disposal sites and warned that similar contamination likely exists in other regions because Wisconsin has the nation’s highest rate of reuse of coal ash.

The waste left after coal is burned can contain concentrated levels of contaminants such as metals — arsenic, chromium, lead, mercury and molybdenum.

The Wisconsin Department of Natural Resources, however, raised questions about the methodology and noted that its own previous study had been unable to trace the source of the high levels of molybdenum in the region.

Of special concern, Clean Wisconsin said, were sites of so-called “beneficial reuse” where the ash had been used as fill for roads and bridges, or on construction sites, even for building a school. The practice is encouraged by the federal Environmental Protection Agency and the Wisconsin Department of Natural Resources.

Tyson Cook, director of science and research for Clean Wisconsin, said the group’s study is the first to link those reuse sites to contaminated wells. “There is a correlation between how close a well is to a coal ash reuse site and how high the levels of molybdenum are in that well,” Cook said.

He added that the issue is of statewide concern because an estimated 85 percent of coal ash is reused rather than being disposed of in lined landfills, where it cannot leach into groundwater.

The group reported that nearly half of 1,000 wells tested in Waukesha, Racine, Milwaukee and Kenosha counties showed high levels of molybdenum.

The metal occurs naturally at low levels. It has been shown at high levels to cause developmental problems in animals and gout-like diseases in humans, leading to joint pains, enlargement of the liver and other problems.

Clean Wisconsin Map of Molybdenum Levels
A map from the Clean Wisconsin report shows molybdenum test results in southeastern Wisconsin. Tyson Cook / Clean Wisconsin
Clean Wisconsin Map of Coal Ash Reuse
Another map in the Clean Wisconsin report shows “beneficial reuse” coal ash sites. Tyson Cook / Clean Wisconsin

The potential connection between coal ash and polluted wells in the region has been investigated previously. The DNR, in a study released last year, focused on three coal ash landfills in the Caledonia area, where many of the contaminated wells are clustered. The DNR’s study did not find evidence that definitively pointed to the landfills as the culprit.

But, according to the Clean Wisconsin report, the agency did not examine coal ash disposed of in reuse projects. The environmental group analyzed DNR records from 1988 through 2012 that showed 1.6 million tons of We Energies coal ash being reused in over 575 projects throughout the region. Five years of data were missing from the DNR’s tallies, according to Clean Wisconsin.

We Energies operates coal-burning power plants in Kenosha and Milwaukee counties.

Ann Coakley, director of DNR’s Bureau of Waste and Materials Management, said that the Clean Wisconsin report did not take into account the differing uses of coal ash in construction. Ninety percent of it, she said, is part of concrete, asphalt or wall board, and will not leach contaminants. But some of the material is used as fill, where it is less contained.

Coakley added that studies by the agency have shown no conclusive connection between sites where coal ash has been used for construction projects and wells with higher levels of molybdenum. She said that with the data used by Clean Wisconsin — wells in different geological settings and at different depths spread over four counties — the link between the ash and contaminated wells remains inconclusive.

“The correlation is not possible to make,” Coakley said. She added that the agency agrees further study is necessary.

Brian Manthey, a spokesman for We Energies, said that the company had not reviewed the report. But he said the company disposes of coal ash by following the regulations set by the DNR and the EPA.

“We believe the current DNR rules are the appropriate regulations for protection of the environment,” Manthey said. “Our disposal is done within the rules set by the DNR. And the EPA encourages beneficial use.”

Manthey said there are also other potential sources of molybdenum and added that it can occur naturally in rock.

But those natural levels are much lower than the levels found in the wells examined by Clean Wisconsin. The report said a survey of 2,700 wells in northern Wisconsin by the Department of Health Services found that 98 percent of samples had concentrations below 20 parts per billion.

About this story

This is the second report produced in The Confluence, a collaborative project involving the Wisconsin Center for Investigative Journalism and students and faculty of the University of Wisconsin-Madison School of Journalism and Mass Communication. The Confluence aims to teach students investigative reporting skills while exploring water quality and supply issues in the Center’s ongoing Water Watch Wisconsin project. The Confluence is supported by a grant managed by the Online News Association and funded by the Excellence and Ethics in Journalism Foundation, the Robert R. McCormick Foundation, the John S. and James L. Knight Foundation and the Democracy Fund.

Water Watch Wisconsin is supported by The Joyce Foundation.

The 1,000 wells examined in the Clean Wisconsin study, however, had an average of nearly 50 parts per billion of molybdenum, higher than the enforcement standard of 40 ppb set for drinking water by the DNR. That is the limit beyond which the agency can require action to correct the problem.

One in five of the wells exceeded the health standard of 90 ppb set by the Department of Health Services. That is the point where DHS recommends “that you not use your water for drinking or in foods where water is a main ingredient and that you find a different source of safe water to drink.”

The state health standard is more than double the EPA advisory level and, according to Clean Wisconsin, allows more molybdenum in drinking than the federal agency recommends children be exposed to for even a single day, 80 ppb.

In 2013, students and staff at Yorkville Elementary School in Racine County learned that the school’s well water was contaminated. Records obtained from the DNR by Clean Wisconsin showed 856 tons of ash were used at the school in a construction project in 2000.

Molybdenum levels were measured at up to 138 ppb, or over 70 percent higher than the one-day exposure level deemed safe for children by the EPA.

Now blue tape cordons off the water fountains and students drink only bottled water.

Katie Nekola, a lawyer for Clean Wisconsin who worked on the project, said the group is asking the state to conduct more testing of groundwater in areas where coal ash has been dumped or reused, establish complete reporting requirements for reuse of coal ash, require more testing of coal ash and stop spreading coal ash until better safeguards are in place.

Ron Seely is a reporter for the Wisconsin Center for Investigative Journalism. Rachael Lallensack, Cole Monka and Daniel McKay are enrolled in one of eight journalism classes participating in The Confluence, a collaborative project involving the Center and UW-Madison School of Journalism and Mass Communication. The nonprofit Center ( collaborates with Wisconsin Public Radio, Wisconsin Public Television, other news media and the journalism school. All works created, published, posted or disseminated by the Center do not necessarily reflect the views or opinions of UW-Madison or any of its affiliates.

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2 replies on “Environmental group links ‘beneficial reuse’ of coal ash to southeastern Wisconsin well contamination”

  1. Ron Seely should have pointed out in his article, “Judge Blames Toxic Kewaunee County Wells…”, that the Wisconsin Department Natural Resources (WDNR) does not have the power to prevent further pollution. Only the State Legislature can take action; and that decision to take action can reference a WDNR recommendation or report. The real questions are, “Where was the (Federal) DNR and WDNR up to this point?” Why does it always take a crisis to move a governmental department to action? Every public drinking water well has to be tested and certified, no matter if it is for a private homeowner or a county/municipality public water well. I would start investigating the water quality tests results for the entire area under scrutiny as well as the State of Wisconsin DNR and various counties’ inspection agencies records for well water quality. You will probably be shocked at the findings…then follow the money.

  2. I posted this Dec. 2nd, but didn’t see it here; I’m guessing the links included were a bad idea so I stripped out the beginning of them. Otherwise I wouldn’t understand why the post would not be approved; my objective to help my neighbors aligns with that of this site. I know that you’d agree, its so important to get accurate information to our community. Thanks Much, LJA

    I beg of you PLEASE, for the sake of my neighbors and community, do more, serious, homework on molybdenum. I’m hoping with all hope you will diligently look into this specifically and help spread the TRUTH about molybdenum, as I’m sure you’re intending to do. First, I am not an advocate for the coal plant and I agree they need to be watched carefully in regards to the environment. Second, I am a resident of the affected area and am doing what I can to get this information to others who are concerned.

    Molybdenum is NOT HARMFUL. You read that correctly.

    I was scared to death when I heard this ‘problem’ in the area, I was ready to buy the reverse osmosis system and make sure all my family and friends were also taking precautions. I have loved ones with liver issues, so the claim that this could affect them acutely sent me reeling. Then I actually read the source the EPA cited as their resource, which is noted at the bottom. The report is large and complicated. Why the information has been disseminated incorrectly is probably a whole other topic, but the important thing for our community to know is they are not going to get sick from molybdenum.

    Important points are these:
    1. The alleged harmful effects are pulled from a report, Koval’skiy 1961, that was DISCREDITED by the same expert source the EPA uses for their guidelines, the Food and Nutrition Board Institute of Medicine.
    2. Recommended levels have been misinterpreted and relayed to the public as Maximum levels.
    3. Pregnant women recommended to ingest MORE Molybdenum in their diet.

    Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc (2001) A Report of the Panel on Micronutrients, Subcommittees on Upper Reference Levels of Nutrients and of Interpretation and Uses of Dietary Reference Intakes, and the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes Food and Nutrition Board Institute of Medicine Written in 2001, NATIONAL ACADEMY PRESS, The National Academies: Advisers to the Nation on Science, Engineering and Medicine, Washington, D.C.

    other sources:
    American Cancer Society:
    World Health Organization:
    Oregon State University:

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