FLINT TWP. — The Flint Township Board of Trustees learned at its Monday meeting that three new monitoring wells on the old landfill site at Bishop International Airport recently tested at nondetectable levels of groundwater contamination.
Paul Bucholtz of the Michigan Department of Environment, Great Lakes and Energy said groundwater monitor wells look at the shallow water atop the clay layer of the ground. EGLE took samples from the groundwater wells in the summer of 2018 and found that three of the six wells exceeded 70 parts per trillion of PFOS and PFOA. Bucholtz said EGLE cleanup criteria are 70 ppt PFOS and PFOA for drinking water protection and 12 ppt PFOS and PFOA for surface water protection. He said the highest concentration found in the three contaminated wells was 810 ppt.
Bucholtz said from April 29 through May 9 this year, EGLE installed three new double-cased monitor wells, which were sampled for contaminants June 6. The final laboratory results received June 28 showed nondetectable levels of all PFAS contaminants in the three wells.
Bucholtz said drilling the new monitoring wells was not an easy operation because the clay layer is very hard.
“The clay is protecting that deeper layer,” he said. “That’s another layer of protection for people south and west of the airport.”
The Linwood Farms area of Flint Township sits close enough to the landfill site to raise concerns about the area’s water quality.
“That’s good news for the residents of Linwood Farms and that area that there’s no PFAS contamination out there,” said Township Supervisor Karyn Miller.
Miller was concerned that the acceptable level of contaminants for drinking water is about six times higher than that of surface water. Bucholtz said the number for drinking water is being re-evaluated and is likely to be reduced to a level closer to that of the surface water.