Residential well testing
Low levels of dioxane have been spreading in groundwater from the old Gelman Sciences filter manufacturing site off Wagner Road for decades. It is thought that thousands of pounds of dioxane were discharged into soil, surface water, seepage lagoons, and in one deep well injection site on the Gelman property. The dioxane groundwater plume is now estimated to be 4 miles long and 1 mile wide, covering portions of Scio Township, Ann Arbor Township, and the City of Ann Arbor. The Michigan Department of Great Lakes, Environment and Energy (EGLE) collaborates with the Washtenaw County Health Department (WCHD) to conduct long-term monitoring of drinking water wells around the Gelman dioxane plume. Drinking water wells within 1,000 feet of the estimated plume boundary are included in this state-funded monitoring. Delineation of the plume boundary has never been conclusively established and the posted boundary lines represent estimates from EGLE. This is the latest map produced by EGLE, and relies on the 7.2 ppb standard to delineate the boundaries of the plume.
Because of concern about potential movement of the dioxane plume, the Board of Trustees authorized sampling of 17 residential wells in July of 2021. The sampling of the wells was conducted by Keith Gadway, PE, Director of Quantum Environmental. Three of these wells tested positive. One had previously tested positive and the other two had no prior sampling history. The two wells are located on N. Wagner Road and Dexter-Ann Arbor Road and had levels of dioxane detected at 0.8 parts per billion (ppb). All affected homeowners have been notified of the testing results. In November, the Board authorized 15 additional well tests near the 2 sites that recently tested positive. This round of testing with the 522 Method has revealed 4 additional drinking water wells that have tested positive on N. Wagner, Miller Road, and Rose Drive. This data is currently under review by Keith Gadway, PE, Washtenaw County, and EGLE. A collaborative plan for additional testing is being formulated.
The wells were sampled using the United States Environmental Protection Agency (USEPA) dioxane analytical method for residential wells, Method 522. This testing method can detect dioxane below 1 ppb, a more sensitive method than that currently used by EGLE and WCHD, which can only detect dioxane levels down to 1 ppb. The Michigan drinking water standard for dioxane is 7.2 ppb. Many states have a drinking water standard of 1 ppb. The use of the 522 Method has long been recommended by advocates for more comprehensive monitoring in areas that are estimated to represent the perimeter of the plume.
The recent testing in Scio documents the presence of dioxane approximately two-thirds of a mile north of what had been estimated to be the boundary of the dioxane plume. Although more data is needed, this finding raises concerns about the validity of the estimated northern boundary of the plume, which right now is placed near M-14. Scio Township will be advocating for EGLE to conduct expanded well testing and more delineation in the areas of recent detections. The possibility for residents in certain areas to obtain 522 Method testing of their own drinking water wells is being explored. The logistics of this are under discussion; as of this writing, no decisions have been made. Details on this next round of testing will be announced on the front page of the website, sciotownship.org.
Circuit Court Update
After holding a hearing on May 3, 2021, Washtenaw County Circuit Court Judge Timothy Connors entered the Fourth Amended and Restated Consent Judgment as an Order of the Court. This Consent Judgment was part of a proposed settlement which was made public in September of 2020 and rejected as insufficient by the elected officials of the Intervenors in the litigation, including Scio Township. The Circuit Court Order requires Gelman to immediately implement all the response activities in the Consent Judgment. Gelman filed an appeal and requested that the Court of Appeals stay implementation of the response activities while the appeal was pending, but its request was denied. As a result, Gelman has been conducting the response activities in the Consent Judgment required by the Circuit Court Order. Briefing on the appeal has been completed and the Court of Appeals will schedule the case for hearing.
EPA update
In April of 2021, EGLE requested that the EPA reinitiate assessment of the Gelman site for possible placement on the National Priorities List. Weston Solutions has been selected to conduct the Gelman Site Inspection, which is the next step to determine if the site continues to be eligible for evaluation as a Superfund National Priorities Site. Weston is currently reviewing available data in order to prepare a site inspection sampling plan.
