The former Genoa Township Oak Pointe Wastewater Treatment Plant has been identified as having PFAS levels above state standards, with follow-up testing of several nearby homes scheduled for next month.
PFAS are a large group of human-made chemicals that have been widely used in fire-fighting foams, stain repellents, nonstick cookware, waterproof clothing and a variety of other consumer goods. They do not easily break down in the environment and are a known human contaminant with links to various cancers.
Michigan adopted tougher new standards in 2020 following a review of toxicology standards that began in 2018.
Groundwater samples were collected by Genoa Township’s consultant in June and August of 2022. The highest results were 19 ppt (parts per trillion) for PFOA (compared to the state maximum of 8 ppt) and 20 ppt for PFOS (compared to the state limit of 16 ppt).
PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonate) are among a large group of lab-made chemicals known collectively is PFAS (perfluoroalkyl and polyfluoroalkyl substances).
Because of those results, the plant was added last week to the Michigan PFAS Action Response Team (MPART) website, with follow-up testing set to be conducted at seven homes closest to the plant, according to Kevin Wojciechowski, Senior Environmental Quality Analyst with the Michigan Department of Environment, Great Lakes, and Energy (EGLE).
“These homes that are being tested on Glenway Drive are on reverse osmosis (RO) systems that were installed and are maintained by Township contractors, because of the historical sodium/chloride groundwater issue,” said Wojciechowski. “Samples for these 7 homes will be tested pre and post filter, which means the drinking water is tested before it goes through the RO system filter and after it passes through the RO filter. All the residents have received a letter on Glenway Drive to explain the sampling and let everyone know who will be sampled in mid-May.”
EGLE and the Department of Health & Human Services (DHHS) will review the sampling results to determine the appropriate health response and evaluate if additional residential wells need to be sampled.
According to the state’s MPART website, the groundwater flow from the plant is to the south/southwest. “Chilson Impoundment and Chilson Creek are downgradient, however sampling of the former WWTP monitoring well network has shown that the PFAS plume does not reach the impoundment and/or creek,” it states.
Located at 5341 Brighton Road, the plant was constructed in 1991 with a designed capacity of 450,00 gallons per day. The treatment plant, which operated until 2015, treated wastewater and discharged it into the ground under a state Groundwater Discharge Permit issued to Genoa Township. The treatment system consisted of sequencing batch reactors, sand filters, and ultraviolet disinfection system. The final treated effluent was discharged to the groundwater on-site via rapid infiltration basins.
Most of the homes on Glenway Drive have reverse osmosis systems maintained by the Township because of the historical sodium/chloride groundwater plume from the former WWTP. The Township and EGLE are working under a Consent Order for the sodium/chloride contamination.
