Michigan’s response to PFAS contamination now includes screening levels for five forms of the chemicals, a move that sets a significantly lower base-line for considering potential health effects for people exposed to them.
The state rolled out the new advisory guidelines on April 4, about six weeks after the Michigan Department of Health and Human Services finalized them.
They were presented by MDHHS as part of the first meeting of the Michigan PFAS Action Response Team after Gov. Gretchen Whitmer announced in March that the state will be setting maximum contaminant levels for the same five types of per- and poly- fluorinated chemicals by spring 2020.
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The screening levels could act as a building block toward reaching that MCL, officials said.
In the meantime, state health officials no longer will be using federal health advisory guidelines for PFAS, which previously only targeted PFOS and PFOA at a combined 70-parts-per-trillion when found in drinking water.
The new health screening levels for drinking water in Michigan are:
“We intentionally designed them to be conservative,” said Jennifer Gray, a state toxicologist, after the presentation. That includes choosing modifying factors that would result in a minimal risk to the most vulnerable population: fetuses and babies, because of transmission through the placenta and breastmilk.
The screening levels will be used “in determining if public health actions or further investigation is needed” when PFAS is found in drinking water, according to a MDHHS spokesperson.
Testing during 2018 determined that PFAS chemicals are found in the drinking water of at least 2 million state residents. State officials recently concluded testing on the largest public water supplies and all schools and daycares.
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Two systems – the water supply in Parchment, near Kalamazoo, and Robinson Elementary School in Grand Haven – had results over 70-ppt for PFOS and PFOA, prompting immediate action by the state.
But there are at least trace amounts found at 62 water supplies and 58 educational centers. Another 25 percent of Michigan’s water systems – mostly representing private wells serving a combined 2.5 million residents – remain untested.
Officials said on April 4 that 49 active investigations are under way at sites with known PFAS contamination. They could not say whether any approaches would change due to the new screening levels.
The screening levels follow a Michigan science panel report in December that urged lowering health standards, but did not identify recommended numbers.
It also comes amid escalating national concerns about the “forever chemicals” linked to cancer, thyroid disorders and neurodevelopment problems. The EPA is evaluating whether it will set limits for PFOS and PFOA; meanwhile, states are setting their own guidelines and enforceable standards. Minnesota, for example, this week reduced its health screening level for PFOS from 27-ppt to 15-ppt.
“We are starting to see more and more states put out numbers in low parts per trillion,” said Erik D. Olson, senior director for health & food for the National Resources Defense Council. "These are very toxic at very low doses and very persistent … and unfortunately very mobile. "
The NRDC recently issued a report saying that Michigan should set enforceable standards for drinking water at 2-ppt for PFOS, PFOA, PFNA and PFHsX.
Michigan health officials didn’t solely rely on the 70-ppt guideline when it determined whether action needed to be taken due to PFAS found in drinking water over the past year, Gray said.
Other factors included site-related information, like the movement in groundwater; and likely additional exposure to PFAS chemicals, which also can be found in consumer products, fish, and firefighting foam.
Those factors will continue to be part of the health evaluation, Gray said, even as Michigan’s new health screening guidelines “can be used as a tool to assist us … and provide some consistency to the process.”
State health officials also continue to look at five additional forms of PFAS: PFBA, PFHpA, PFHxA, PFPeA and 6:2 FTS. Enough information to set screening levels was not available on any of them, but that may change in the future, officials said.
Beyond the new screening levels, state officials on April 4 also set up the process to name the science panel that will use health-based criteria to recommend the maximum contaminant level by July 1. Steve Sliver, head of MPART, will name 3-5 people to the panel by mid-April.
As the state moves forward toward setting enforceable PFAS standards for Michigan, the discussions will get very technical, warned Liesl Clark, director of the DEQ.
“It will be important to understand the policy implications and the scientific implications” of the many numbers that will be discussed, she said.
“This is an important first step … and it’s happening on a fairly aggressive timeline,” Clark said.