Ann Arbor-Area Groundwater Shows Traces of Carcinogen
Contamination of groundwater by traces of a likely carcinogen, 1,4-dioxane, has been identified in the Ann Arbor area of Michigan. Recent testing carried out by two townships and a state monitoring program has revealed that 43 drinking water wells located north of I-94 and M-14 have been contaminated by low levels of the chemical. The results are of concern to clean water advocates due to the proximity of the contaminated area to the Huron River, which serves as Ann Arbor’s main source of drinking water. This contamination is separate from the known Gelman dioxane plume, causing further alarm.
All samples taken to detect the chemical were below the state drinking water standard of 3 parts per billion, which falls significantly below the dioxane standard of 7.2 ppb. However, residents have long called for stricter standards, as other states have implemented more stringent regulations. The contamination originates from the Gelman Sciences filter manufacturing facility on Wagner Road in Scio Township, where the plume was first discovered in the 1980s.
The recent map published by the Washtenaw County Health Department shows a finger-like extension of the pollution spreading north of the highways on the eastern side of Wagner Road toward the Huron River. However, it is too early to determine the exact implications of these results, as the area has not been tested before. Kristen Schweighoefer, the environmental health director with the health department, suggests that more monitoring is required in this area to gain a comprehensive understanding.
Concerns regarding this particular residential area north of M-14 were heightened in 2021 when Scio Township conducted its own sampling of wells. The results indicated pollution approximately two thirds of a mile north of the estimated plume boundaries, prompting the township to carry out further testing. A long-term state monitoring program had previously sampled the area just north of I-94, but the scope of testing was expanded due to the township’s detections.
The health department’s recent testing confirmed the findings of the independent Scio Township testing. Environmental remediation professional Dan Bicknell, who discovered the Gelman plume in 1984, states that the results prove the contamination of residential drinking water wells up to one mile beyond the edges assumed by the Michigan Department of Environment, Great Lakes and Energy (EGLE). Bicknell is urging for the plume to be designated as a federal Superfund site to enable a more effective cleanup process.
The EPA is currently evaluating the Gelman plume and has expressed preliminary indications that it meets the criteria for Superfund status. Officially proposing the site for Superfund status is expected to occur in fall 2024, subject to approval from the EPA’s headquarters and a federal rule-making process. Bicknell emphasizes that federal oversight is crucial to prevent further migration of the plume and to address the health concerns associated with the contaminated groundwater.
Moving forward, the health department plans to continue monitoring the affected area and will collaborate with EGLE to determine the locations for further sampling. While no final decision has been made regarding additional sampling north of M-14, Schweighoefer anticipates that it will be included in the future sampling plan. The aim is to gather more data over time and to find the most effective measures for cleaning up the contamination.
As the investigation into the Ann Arbor-area groundwater contamination continues, it is imperative to ensure the implementation of strict regulations and proactive measures to protect public health and the environment.
