East Michigan News

A Central Michigan University student researching a slow-moving plume of hazardous chemicals made a discovery that prompted a state agency to pause its use of a fish-stocking pond.

Eleanor McFarlan was investigating the impact of three manmade ponds near Belmont, in Kent County, on the flow of groundwater containing contaminants dumped into a nearby landfill during the 1960s. The contaminants belonged to the family of chemicals known as PFAS.

PFAS have been used in various consumer applications for years. Concerns have emerged about their impact on human health, particularly due to their ability to accumulate in the body and their slow degradation rate.

The ponds were also used by the Department of Natural Resources (DNR) for its walleye stocking program. During her research in 2023, McFarlan discovered that the water had higher concentrations of PFAS compared to previous testing in 2018.

“When Lemke and I received our sample results, we made sure to contact the DNR about our findings,” McFarlan said. “PFAS are an emerging contaminant of concern, meaning that their behavior in the environment is not well-recognized."

“Understanding how PFAS moves in the subsurface is essential for protecting our natural resources, and this research will hopefully help others characterize the extent of PFAS contamination in similar sites.”

The concentrations were below what is considered harmful to human health but still high enough to get the DNR’s attention. The agency performed its own tests, including on the fish.

“Although the data indicated no human health risk associated with the walleye program, walleye rearing activities have been suspended at the Belmont Ponds out of an abundance of caution,” said Ed Golder, a DNR spokesman.

The fish would have been small enough when released that almost all of the PFAS they continued to collect would have come from their new homes rather than from the stocking pond, Golder added.

“Eleanor’s study demonstrates the importance of interactions between groundwater and surface water,” said Lawrence Lemke, CMU Professor of Environmental Geology. “If groundwater is contaminated by PFAS or other chemicals, it can affect rivers, lakes, and ponds that it feeds into.”

McFarlan’s research was part of an ongoing effort by CMU students studying PFAS deposited in House Street landfill uphill from the ponds, said Lemke. Groundwater containing contaminants has very slowly migrated towards Rogue River since then. The ponds lie between these two points. The DNR has used them to raise walleye and minnows since 2014.

Earlier research by CMU students found that PFAS seeped deep into the ground before starting its migration toward Rogue River.

“In 2020, a team of CMU students built a numerical model to simulate PFAS migration from the landfill over the past 60 years,” Lemke said. “Now we’re beginning to understand where PFAS will end up in future.”

The DNR started using these ponds before concerns about PFAS arose but while plumes from landfills were already making their way underground towards them.