Minnesota DNR to test deer tissue for ‘forever chemicals’

Whitetail buck
A whitetail buck seen in a Twin Cities park. The DNR plans to collect liver and muscle tissues from deer killed by hunters in Duluth and the east Twin Cities metro.
Tim Post for MPR News File

Updated: 12:17 p.m.

For the first time, the Minnesota Department of Natural Resources will test samples from wild deer for industrial chemicals known as PFAS.

The DNR plans to collect liver and muscle tissues from 60 deer killed by hunters in Duluth and the east Twin Cities metro, areas known to have PFAS contamination.

PFAS, or per- and polyfluoroalkyl substances, are man-made chemicals that have been used in a variety of products, including water-repellent clothing and firefighting foam.

The Wisconsin DNR recently advised people not to eat livers from deer harvested within 5 miles of a facility in Marinette that tested firefighting foam. The advisory came after researchers detected PFAS in 20 deer harvested near the JCI/Tyco facility.

In 2018, Michigan issued “do not eat” advisories for deer taken within 5 miles of Wurtsmith Air Force Base in the northeastern part of the state.

"That prompted us to consider if there were similar areas in our state where we should consider sampling deer, to determine if that chemical is accumulating in wild deer around those areas in Minnesota,” said Barb Keller, big game program leader for the Minnesota DNR.

Keller said the DNR is working with bow hunters participating in special hunts near the Duluth airport south of Rice Lake Reservoir and near Oakdale in the east metro to voluntarily submit samples.

Because there is limited hunting in the Twin Cities metro, the DNR is exploring other ways of collecting samples from that area, such as from road-killed deer, she said.

Jim Kelly, manager of the environmental health division at the Minnesota Department of Health, said the concern is over places where PFAS has been released into the environment through spills, leaks or waste sites and has contaminated surface waters, such as creeks or ponds.

“We know that PFAS can sometimes concentrate to some extent on the surface layer of the water,” Kelly said. “So deer who are drinking at that surface may be exposed to it.”

The testing of deer for PFAS may be new in Minnesota, but concerns over the exposure of wildlife to the chemicals are not. The state health department already advises people not to eat any fish from Lake Elmo or any largemouth bass from Lake Harriet due to PFAS contamination.

PFAS don’t break down easily and can accumulate in the environment, as well as in the human body. Studies have linked long-term exposure to certain levels of PFAS to health problems in humans, including liver and thyroid disease, developmental issues and certain types of cancer. 

Human exposure to PFAS often occurs through drinking water or food packaging. Scientists are trying to learn more about PFAS in deer and other wildlife that drink from lakes and rivers contaminated with the chemicals.

The liver filters toxins from the blood, so chemicals such as PFAS likely would accumulate in the highest concentrations in a deer’s liver, Keller said. If PFAS are detected in the liver samples, then researchers will test the muscle tissue as well, she said.

Keller said the DNR will be working with the Minnesota Pollution Control Agency and the state Department of Health to interpret the results from the pilot study and decide if any health advisories should be issued for consuming Minnesota’s wild deer. Results won’t be available for a couple of months, she said, so any advisories would not be issued until after this year’s deer hunting season.

Keller said the agencies also will use the results from the pilot study to decide if there are other areas in Minnesota where deer should be tested.

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