ASHLAND TOWNSHIP, Mich. (WOOD) — The site of a former sewage lagoon system has been identified as a PFAS pollution site by the Michigan PFAS Action Response Team.

MPART issued a release Monday to report elevated levels of PFAS were found at the former lagoon near the intersection of South Ferris Avenue and West 128th Street, about 1.5 miles southwest of Grant.

The Riveridge Sewage Lagoon was once authorized to discharge 2,600 gallons of treated wastewater per day. It was shut down “when the lagoon no longer met the standards for operation” and was replaced by an underground drain field. The lagoon “residuals” were removed and disposed at a licensed landfill.

Michigan’s Department of Environment, Great Lakes and Environment ordered groundwater sampling to follow up with the lagoon because PFAS is so commonly used in household products.

Two of the four groundwater monitoring wells showed levels of perfluorooctane sulfonic acid, commonly referred to as PFOS, at 21 parts per trillion. The state’s safety threshold for PFOS in groundwater is 16 ppt.

Measurements at two other wells on the southern edge of the lagoon came back within safe ranges and PFAS wasn’t detected at the well at the northern edge of the site.

MPART officials believe the PFOS pollution is held to the small site. There are no bodies of water near the former lagoon and the closest drinking wells, which are between 600 and 800 feet south of the site, do not appear to be affected.

PFAS — or per- and polyfluoroalkyl substances — is a giant group of chemical compounds that were first developed in the 1940s and incorporated into all sorts of products for its waterproofing and heat-resistant properties. However, decades later, research showed that PFAS compounds do not organically break down and can build up in the human body, causing serious health problems including cancer.

EGLE plans to work with the property owner on continuing to monitor the groundwater levels.