Changes on the way to clean-up plan for contaminated groundwater under Ann Arbor
At least six homes in the Evergreen subdivision will have to switch from well to city water under changes to the clean-up plan for a plume of contaminated groundwater under parts of Ann Arbor.
Changes were enacted this week between the Michigan Department of Natural Resources and Environment and Pall Life Sciences in Washtenaw County Circuit Court following disputes between the two sides on how to move forward with clean up of the decades-old contamination.
Currently, thousands of households in the prohibition zone in the northwest section of Ann Arbor can’t use groundwater or dig wells due to concerns over dioxane pollution.
Because some properties exist as township islands within the city of Ann Arbor, the switchover to the municipal water supply means the homes will be annexed to the city and the residents will pay the taxes associated with city life.
The prohibition zone exists due to a patchwork of contamination sites locals call the Gelman plume. It fans out in the groundwater from the Pall site at 600 S. Wagner Road both to the east into township and to the west in a swath under the west side of Ann Arbor. The plume is estimated to be roughly a mile wide and three miles long.
Pall would be required to pay for the homes’ hook-up to the city water supply, said Sybil Kolon, a senior environmental quality analyst for the MDNRE. There may be more homes on wells that need to be switched to the city water supply within the new, larger prohibition zone, Ann Arbor officials said.
"It's Pall's responsibility to investiage the new expanded prohibition zone, find where the wells are and then get those properties connected to city water," said Molly Wade, water treatment services manager for Ann Arbor.
The two sides began negotiating the most recent changes to the plan since 2008. Pall inherited the responsibility to clean 1,4 dioxane pollution created by Gelman Sciences between the mid-1960s and the mid-1980s when Pall purchased the company in 1997. Dioxane is an industrial solvent that was used to manufacture medical filters at Gelman.
An agreement reached in Washtenaw County Circuit Court Tuesday means the MDNRE will provide oversight over these and other revised clean-up provisions:
â€¢ Groundwater under a portion of Ann Arbor’s Evergreen subdivision will monitored for the possible human carcinogen 1,4 dioxane rather than cleaned up. Some remediation will continue under Evergreen, but at a lower rate.
â€¢ Pall is in the process of installing four monitoring well clusters to detect movement of the plume. MDNRE officials can ask Pall to add more, though that is not covered in the latest agreement, Kolon said.
â€¢ Pall could build a new underground pipeline to its Wagner Road facility to treat tainted groundwater under the Maple Village shopping center, Kolon said. Most of the pipeline is in place, but a connector pipe along Dexter between Maple Road and Allison Drive would be necessary.
â€¢ Around the Pall Life Sciences facility off of Wagner Road, the company will reduce how much water it is purging from the ground, treating and discharging to the Honey Creek tributary.
The MDNRE will host public hearing explaining these and other changes to the clean-up plan 7 p.m. Wednesday, March 30, at Abbot Elementary School, 2670 Sequoia Parkway, Ann Arbor.