The manufacturing company Gelman Sciences will be required to take new steps to address its slowly expanding plume of groundwater contamination in and around Ann Arbor, under an agreement reached with the U.S. Environmental Protection Agency.
On Friday, the EPA announced an administrative settlement agreement with Gelman Sciences LLC. Under the agreement, the company will take steps to track and reduce the spread of the so-called “Gelman plume,” as well as evaluate plans for cleanup.
The Gelman plume is a body of groundwater contaminated by the chemical 1,4-dioxane. The plume stretches roughly 3 to 4 square miles underground, just west of the Huron River, and "has migrated into aquifers that supply drinking water," the EPA said.
1,4-dioxane is “likely to be carcinogenic to humans,” according to the EPA. Although little is known about the specific impacts to human health, studies on animals show the chemical can cause liver and kidney damage.
The plume was first discovered in 1986 on the site of Gelman’s medical filter manufacturing facility, nearly 20 years after Gelman began dumping contaminated wastewater on the site.
Since its discovery, the plume has continued to spread, raising concerns that it may eventually reach the Huron River and enter Barton Pond, the source of 85% of Ann Arbor’s drinking water.
In March, the EPA added the Gelman Plume to the Superfund National Priorities List, paving the way for additional EPA oversight, including the new settlement agreement.
Under the agreement, Gelman will be required to:
- Take steps to slow the plume's spread toward the Huron River by increasing groundwater extraction and treatment on the eastern edge of the plume
- Increase monitoring to better define the eastern edge of the plume
- Excavate contaminated soil from an area of the former Gelman facility
- Conduct a feasibility study to evaluate the extent of contamination and potential remediation efforts.
- Fund the hiring of an independent expert to help explain technical information about the site conditions and potential actions to the community.
The Gelman plume is also managed under a 1992 court-supervised consent judgement between Gelman and the state of Michigan. That judgement required the company to manage the spread of 1,4-dioxane on the site, without assuming liability for the contamination. Local advocates have said that agreement doesn’t do nearly enough.
Rebecca Esselman, executive director at the Huron River Watershed Council, said she was encouraged by the announcement of the federal settlement, although she had not yet been able to review all the details of the 100-page agreement.
But, Esselman said, “what we know about groundwater contaminations like this is there's no cleaning it up 100%. And that is a legacy that we'll have to live with in perpetuity in the Huron River.”
The Gelman plume will need “an aggressive cleanup,” Esselman said. “And residents and local governments have waited too long and the risks are too high for anything shy of that.”
Michigan Public's Tracy Samilton contributed reporting
