UW-L research shows decline in mercury contamination

Image of  Mark Sandheinrich  and Sean Bailey sitting in a canoe and diping their nets in the waters of Shoepack Lake.


From left, Mark Sandheinrich, head of UW-L’s River Studies Center, and Sean Bailey, ’03, a UW-L graduate student and independent contractor for USGS, dip their nets in the waters of Shoepack Lake.

UW-La Crosse student researchers contributed to a long-term study that shows mercury levels have decreased in waters of the Minnesota Great Lakes Region — a potential indicator that mercury pollution is on the decline.

The study was a collaboration between UW-L, the U.S. Geological Survey, the National Park Service and the National Atmospheric Deposition Program.

However, it couldn’t have happened without about 35 undergraduate and graduate UW-L students who’ve helped collect and analyze fish over the course of the study, says Mark Sandheinrich, head of UW-L’s River Studies Center and co-author of the study.

Each year, a group of UW-L biology and chemistry students pack up their bug spray and fish nets to paddle through waters of Voyagers National Park. They collect small perch and northern pike to analyze for mercury contamination.

Paul Drevnick, ’02, was one of those students more than a decade ago. He calls the opportunity a springboard into his career. Today he is a research scientist of aquatic ecology at the University of Michigan’s biological station. His research is about understanding mercury cycling in a changing world.

As a UW-L graduate student in biology, he realized that in the future he could be working in places that appeared pristine, but were actually greatly affected by atmospheric contaminants, he says.

“I’m still doing mercury research because it’s an interesting topic and also an important topic for human health,” he notes.

Today Drevnick remains in close contact with his former UW-L mentors — Sandheinrich and Jim Wiener — who he now considers “lifelong friends and colleagues,” he says.

Image of people standing on the shoreline near the water of Voyagers National Park.

UW-L researchers and a Minnesota Pollution Control Agency staff member pictured at Voyagers National Park.

The results

The report was published in the Environmental Science and Technology journal indicating that from 2001 to 2012 mercury in small perch from two remote lakes — Lake Ryan and Lake Peary — declined by 34.5 percent and mercury in the water of these lakes declined by 46.5 percent. The results imply that efforts to reduce mercury pollution in the U.S. and Canada are working.

“Reduced mercury output is going to result in less mercury in lakes and fish,” says Sandheinrich. “That’s good news for humans, wildlife who consume the fish and the fish themselves.”

UW-La Crosse scientists have been studying mercury in lakes and rivers of the Upper Midwest for decades, contributing to the weight of evidence that shows what a serious problem the most toxic form of mercury — methylmercury — is for fish, wildlife and humans.

UW-L faculty and staff have been to Voyagers National Park since 2000. Jim Wiener, Wisconsin Distinguished Professor and another co-author of the study, was the first to make the trip. Today UW-L students and faculty sample interior lakes of the park. Students have the opportunity to work with cutting-edge instruments, gain field and laboratory experience, collaborate with various agencies and work on an important world problem, says Sandheinrich.

“Nationally, every state of the continental U.S. has a fish consumption advisory in one or more bodies of water,” he says. “It’s an important environmental issue.”

Sean Bailey, a UW-L graduate student and employee at USGS, worked at River Studies Center on and off for 7 ½ years.

“The River Studies Center is involved with many people who are very active leaders in the field (of mercury research), including people right at the River Studies Center,” he says. “The work really relies on having a lot of people, including students to do the work.”