Toxic Plume in Michigan Aquifer May Finally Get Cleaned Up

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By Stephen Joyce

A toxic plume that has lingered for decades in the groundwater beneath Ann Arbor, Mich., and its surroundings may finally get the comprehensive cleanup residents say it needs after local officials persuaded federal regulators to step in.

Michigan municipal officials dissatisfied with their state’s response to a hazardous chemical plume in the Ann Arbor area persuaded the Environmental Protection Agency to assess whether the site qualifies for federal Superfund oversight.

The Michigan Department of Environmental Quality (MDEQ) has been monitoring 1,4 dioxane, a likely carcinogen, in the area for decades. But local leaders say the state is not adequately addressing risks posed by the plume.

“The EPA needs to gets involved to clean this up. Otherwise it’s going to be more of the same from the state of Michigan,” Ann Arbor Charter Township supervisor Michael Moran told Bloomberg BNA. “Because of a complete lack of attention by the MDEQ the plume has become much larger and much more widespread,” he said.

Robert Wagner, MDEQ environment deputy director, told Bloomberg BNA the state and and the owner of the contaminated site, Gelman Sciences Inc. and its successors, have been monitoring the safety of Ann Arbor drinking water using a network of monitoring wells and to date have not found any exposure to 1,4-dioxane in the municipality’s drinking water. Remediation efforts continue, meanwhile, by pumping contaminated water out of the underground aquifer, he said.

Was the State Agency Effective?

Ann Arbor Charter Township and others filed Nov. 18 a petition with the federal EPA criticizing the state’s performance at remedying damage at the site, saying it necessitates broader EPA intervention.

Robert Kaplan, EPA acting region 5 administrator, said in a Feb. 1 letter to Ann Arbor Charter Township, Scio Township and Sierra Club-Huron Valley Group the EPA has agreed to conduct and complete the assessment by Nov. 18, 2017.

Contamination has occurred on site and off site due to the site’s topographical height, a situation worsened by “continuing DEQ delays and mismanagement on this vast groundwater contamination site,” the petition said.

The plume has worsened despite a 1992 Washtenaw County, Mich. court order requiring the site’s owner to implement response actions to address environmental contamination in the vicinity of the site, subject to MDEQ approval.

Roger Rayle, co-founder of environmental group Scio Residents for Safe Water who has been pushing for remediation of the site for more than 20 years, and others said the order has been violated with little adverse consequence.

“I just don’t think the state is moving in the right direction,” Rayle told Bloomberg BNA.

“This is just like Flint,” said Dan Bicknell, referring to an ongoing contaminated drinking water crisis in Flint Mich. that was triggered years ago by a change in the city’s water source. The MDEQ is “not listening to the public nor are they enforcing the state laws as they should be enforced. State laws do not allow this sort of expansion of the plume,” Bicknell, a former USEPA Superfund enforcement officer, told Bloomberg BNA.

Plume Expanding

The petition asking for a Comprehensive Environmental Response, Compensation, and Liability Act (or Superfund) preliminary assessment said area residents are endangered by the release and threatened release of 1,4-dioxane at the site, which Danaher Corp. currently owns.

The potential for exposure is there.

“Currently, approximately four homes in Scio Township have dioxane ranging from 1 ug/L to 4 ug/L in their drinking water wells,” the petition said.

The chemical plume, located in Scio Township, is now more than four miles long and one mile wide and “continues to expand with no effective off-site hydraulic control, thereby contaminating a currently pristine groundwater resource, drinking water supplies and buildings,” the petition said.

At risk is about 85 percent of the drinking water resources Ann Arbor supplies to approximately 120,000 residents, in addition to vapor intrusion risks, the petition said.

“I’m pleased the EPA will conduct a preliminary assessment of the dioxane plume to determine whether it is eligible for cleanup as a federal Superfund site. This will take time and it is not a silver bullet, but it is critical to explore all options available to the community to ensure this contamination is properly remediated,” Rep. Debbie Dingell (D-Mich.) said in a Feb. 2 statement.

Michigan is home to 65 Superfund sites.

Scope of Problem

The petitioners’ preference is for the contaminated groundwater to be pumped out of the aquifer, halting the spread of the contaminated plume and then allowing it to be recharged with pristine water.

Proper site remediation could take decades and cost as much as $50 million, or perhaps even more, said Bicknell, currently the president of Global Environment Alliance LLC, an environmental consultancy that helped draft the petition.

Following the assessment, if USEPA, after a public comment period, places the site on its Superfund National Priorities List, the federal agency would then negotiate an administrative order with the site’s owner detailing necessary actions to clean up the site.

Gelman Sciences Inc. used 1,4-dioxane when manufacturing medical filters from 1966 to 1986 at the site. Disposal methods caused widespread groundwater contamination, according to a MDEQ fact sheet.

Dioxane is a likely human carcinogen whose physical and chemical properties—it is highly mobile and not readily biodegradable—make if difficult to treat.

A Gelman spokesman declined to comment on the matter.

To contact the reporter on this story: Stephen Joyce in Chicago at

To contact the editor responsible for this story: Larry Pearl at

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