Surface water levels of PFAS chemicals have plummeted in a creek that flows into the Huron River, after a state investigation.
Investigators went upstream from Ann Arbor to try to discover the source or sources after PFAS chemicals showed up in the city's treated drinking water in 2018.
A main source was discovered to be the Wixom Wastewater Treatment Plant, which was discharging PFAS-laden effluent from Tribar Manufacturing, a plating company, into Norton Creek, which flows into the Huron River.
Surface levels of PFAS chemicals went from a high of 1,400 parts per trillion in the creek, to six parts per trillion after the company installed filtration systems and began filtering PFAS out of its effluent.
State officials say there are still hundreds, if not thousands, of sources of PFAS in the larger Huron River watershed, which comprises parts of 7 counties over 900 square miles.
EGLE (Environment, Great Lakes and Energy) Department spokesman Scott Dean says the success story is a sign that the state's voluntary PFAS program is working. Companies do not have to monitor and disclose their PFAS discharges, but once it's discovered they are discharging PFAS chemicals over the state limit, they are expected to work cooperatively with state officials to lower the discharges to meet the limit.
There is still a "do not eat" advisory for all fish in the portion of the Huron River that flows south from Wixom, due to high levels of PFOS, a PFAS chemical, in tested tissues of many species of fish. That testing continues to determine how fast PFOS levels in fish decline after major sources of PFAS are identified and cleaned up.
PFAS chemicals are of concern because they do not break down in the environment over hundreds or thousands of years, and can accumulate in very high amounts in the bodies of fish and mammals, including humans.
The chemicals are linked to a number of health issues, including neurological problems and possibly cancer.