Wolverine Worldwide said they will only provide filters for homes with water contaminated by two PFAS compounds, despite there being Belmont wells with detections of a lesser-known compound present in a product used by the company.
Since July of last year, state officials have recorded more than 300 homes in northern Kent County that are contaminated with industrial PFAS chemicals traced back to waste dumped by Wolverine Worldwide.
Wolverine has tested the wells at its own expense and installed more than 450 in-home filtration systems at homes in the testing area to eliminate the chemicals. The activated-carbon filters target PFOS/PFOA, two in-family chemicals present in 3M's Scotchgard, which Wolverine used to waterproof shoes.
3M phased PFOS/PFOA out of Scotchgard in 2002 and began using perfluorobutanesulfonic acid (PFBS) in the product. Former employees at the Wolverine Worldwide tannery confirmed the company used Scotchgard after 2002.
The chemical is similar to PFOS/PFOA, but has a four-carbon chain and a shorter half-life, said Kory Groetsch, environmental public health leader for the Michigan Department of Health and Human Services (MDHHS).
"It tends to stay in the body a much shorter amount of time," Groetsch said. "We're in a learning curve on this one."
Unlike PFOS/PFOA, which has a 70 parts per trillion (ppt) safe drinking water advisory level set by the U.S. Environmental Protection Agency and the state of Michigan, PFBS has no federal or state drinking water advisory.
The health effects for PFBS appear to be similar to those of PFOS/PFOA, Groetsch said, alluding to a report from the Minnesota Department of Health. The December 2017 report said PFBS caused changes in the thyroid and kidney in laboratory animal studies, along with delayed development. There is very little information on health effects in humans.
Wolverine Worldwide said it would provide the activated-carbon whole-house filters to households with any PFOS or PFOA detections, but said no to a Belmont household that tested at 67 ppt for PFBS.
Smaller PFAS compounds, such as perfluorobutanesulfonic acid (PFBS), are eliminated from bodies within days and do not present any human health concerns at low levels, according to a Wolverine statement citing Dr. Janet Anderson, a consulting toxicologist who contributes to Wolverine blog posts regarding PFAS.
"Based on the data available at this time, Wolverine is not providing filters for PFBS detections," the statement said.
A 2014 report by the Nation Center for Environmental Assessment found that the average half-life of PFBS in humans was 25.8 days.
The activated-carbon PFAS filters will also remove PFBS compounds, said Richard Rediske, an environmental chemist and professor at Grand Valley State University's Annis Water Resources Institute.
"It's the prescribed remedy throughout the United States," Rediske said last month when discussing the filters. "All the active sites in the carbon attract the PFAS chemicals, and they stick to the carbon particles. And the water comes out clean."
The village of Sparta shut down one of its wells after it detected PFBS between 2-3 ppt earlier this month.
Groetsch said MDHHS toxicologists are currently researching PFBS chemicals and how to view them relative to PFOS/PFOA.
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