A total of 8 parts per trillion (ppt) of PFOS and PFOA per- and polyfluoroalkyl substances were detected in August by an independent study, and NOWS Water Facilities Manager Joe VanderStel said the new findings confirm the low levels.
Still, a minimum of annual testing will be required at the NOWS plant going forward, according to VanderStel, but more frequent testing could be pursued.
PFAS is a large group of synthetic compounds that are water and lipid resistant. They are found throughout the environment and are used in common items such as firefighting foam, water-repellent materials and non-stick cookware.
PFAS has been linked in human studies to some forms of cancer, thyroid disorders, elevated cholesterol and other diseases.
The study at NOWS in August found 4 ppt perfluorooctane sulfonate (PFOS) and 4 ppt perfluorooctanoic acid (PFOA), well below the U.S. Environmental Protection Agency’s (EPA) combined “actionable” level of 70 ppt.
The separate studies used the same methodology, VanderStel said, sampling both raw source water and tap water leaving the facility. The MDEQ study, conducted Oct. 8, also employed an isotope testing for added precision.
VanderStel said he is not surprised by the differing results, as they were conducted at different times of year and by different laboratories.
“Trying to get down to the very small, detailed parts per trillion, there’s always going to be some variance,” he said.
The EPA is working to establish a required limit for the two PFAS chemicals, as the MDEQ continues a statewide study of the chemicals found in the many thousands parts per trillion in Rockford, Parchment and other Michigan sites.
“You’ve got to take your hat off to the state of Michigan for moving forward with this and getting it done,” VanderStel said. “Hopefully, the EPA moves quickly, too.”
VanderStel said one or two studies cannot be relied upon for a definitive answer to whether there is PFAS in the water. More regular testing will be necessary to gain a more accurate picture.
“The results are only as good as how many times you do it,” he said. “The frequency reassures you that the water is safe.”
The NOWS plant serves Grand Haven, Ferrysburg, Spring Lake, Grand Haven Township, Spring Lake Township and Crockery Township, with water drawn from two intakes buried beneath the sand in Lake Michigan.