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MDHHS updates 'Do Not Eat' advisory for deer near Clark's Marsh; Advisory now applies to smaller area based on recent PFAS data analysis

The Michigan Department of Health and Human Services (MDHHS) is reducing the coverage area of its 'Do Not Eat' advisory for white-tailed deer taken from the Clark's Marsh area in Oscoda Township in Iosco County. The advisory now applies to deer taken from within a three-mile radius of the marsh instead of the previous five-mile radius.

The original five-mile 'Do Not Eat' advisory was issued in 2018 after tissue from one of 20 deer taken near Clark's Marsh showed extremely high levels of perfluorooctanesulfonic acid (PFOS), a type of per-and polyfluoroalkyl substance (PFAS), which is associated with harmful health effects in people, including reduced fertility, thyroid disease and liver damage.

"As we have now gathered additional data about deer, PFAS levels and their proximity to Clark's Marsh, we have updated our health advisory," said Dr. Joneigh Khaldun, chief medical executive and chief deputy for health at MDHHS. "We will continue to monitor PFAS levels in wildlife to help protect the health and safety of Michiganders who hunt and fish in this area."

In 2020, an additional 44 deer were collected around Clark's Marsh. Muscle and liver samples from these deer were tested for PFAS. Deer from the 2020 collection

had various PFAS, including PFOS, in their muscle and liver samples. After analyzing the available data from 2018 and 2020, MDHHS discovered a relationship between detections of PFOS in a deer and the deer's proximity to Clark's Marsh.

The data showed that deer living closer to the marsh were more likely to have PFOS in their livers. The finding is included in the 2021 report PFAS levels in Michigan Deer from the Oscoda Area, Iosco County.

 A map of the new advisory area is located online.

A 'Do Not Eat' advisory for all fish and aquatic or semi-aquatic wildlife taken from Clark's Marsh remains in place. This includes fish, aquatic and semi-aquatic mammals (including muskrats), amphibians (including frogs), mollusks (including snails), reptiles (including turtles) and arthropods (including crayfish).

In addition, MDHHS continues to recommend people do not eat organs from any fish, deer or other wild game in the state because many chemicals, including PFAS, can accumulate in the organs of wildlife.

For more information, visit

For more information about wild game consumption, visit

For health-related questions, please contact MDHHS at 800-648-6942.

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