APPLETON, Wis. — A new study is raising concerns about the safety of eating fish from Lake Winnebago.
The research reveals tiny pieces of plastic are skirting the wastewater treatment process to end up in the lake, where they can soak up toxins and are likely being consumed by fish.
Experts say there’s a potential danger that those toxins could be passed on to people who consume fish from the lake.
“It’s definitely a concern,” said Kelly Reyer, outreach coordinator for the Fox-Wolf Watershed Alliance. “It can go through the food chain and potentially harm the ecosystem as well as public health because of people consuming the fish.”
Plastic microbeads had previously been found in the Great Lakes, prompting state legislation to phase out products that contain them, but experts didn’t know whether they were in Lake Winnebago or other inland waters.
The research on Lake Winnebago was conducted in response to questions from USA TODAY NETWORK-Wisconsin about the presence of microbeads in the lake.
The discovery of the beads in Lake Winnebago suggests they’re likely also present anywhere else that wastewater is discharged.
Lead researcher Lorena Rios Mendoza said she would advise against eating fish from these areas, though more exploration is needed to determine whether it’s truly dangerous.
Microbeads — used as exfoliants in scrubs and washed down the drain — act as sponges for harmful chemicals in the water, including some that can contribute to cancer and disrupt hormone levels.
State and national bans start to go into effect this year to stop the sale of personal care products and over-the-counter drugs containing microbeads over the next few years. But microbeads are stubborn; those already in the lake could be stuck there for centuries without degrading.
And they’re not the only source of plastic in the lakes.
Other microplastics found in Lake Winnebago include fragments of plastic litter that have been dumped near the lake or picked up in rainwater flowing into the lake. Clothing can also shed plastic microfibers into the water system. All these materials can absorb toxins.
“We need to do something,” said Rios Mendoza, an associate professor of chemistry at UW-Superior who analyzed the lake water. “The plastic is not biodegradable and it can stay here forever and ever.”
Rios Mendoza advocates for further research, more public education, and reduction of plastic waste by manufacturers and consumers.
Finding the plastics was a team effort. Autumn Fisher, current supervisor and former lead water quality analyst at the Fond du Lac Wastewater Treatment Plant, collected water samples with her team last fall from three sources: the stream of wastewater running into their facility, the water they discharge into the lake, and water in the middle of the lake.
Fisher then mailed the samples to Rios Mendoza, a leading researcher on microbeads who volunteered to help.
Rios Mendoza found a slew of microbeads, microfibers and microplastics in all the samples, demonstrating that some of the tiny plastics (less than 5 millimeters long) are able to pass through the water treatment facility.
Rios Mendoza estimated that about 400 microbeads flow into Lake Winnebago from the facility every day.
From the initial sampling, it’s unclear how dangerous the concentration is in Winnebago. Rios Mendoza said more samples of water and fish are needed to determine how the plastics are impacting wildlife and to decide whether fishing is safe on Lake Winnebago.
Lake Winnebago, the state’s largest inland lake, is also the source of drinking water for Oshkosh, Appleton and other Fox Valley areas. But the water goes through more vigorous filtration before making it to the tap.
Jennifer Sereno, a spokesperson for the state Department of Natural Resources, said the filtration process for drinking water catches much smaller particles than most microbeads. When asked if the department thought microbeads could pose a threat to public health, she pointed to a Journal Sentinel story about the upcoming state ban. That story notes that the microbeads can be harmful to fish who eat them, and to humans who eat the fish.
Fisher said Fond du Lac’s wastewater plant is treating the water as carefully as possible with the technology on hand. She expects any upgrade to filter out microplastics would cost tens of millions of dollars, which would be a hard sell when the facility already is anticipating costs associated with meeting more stringent regulations coming from the DNR on phosphorous discharges.
“We’re doing what we can at this point, without a complete upgrade at a pretty costly capital investment, to remove what we can,” Fisher said. “But unfortunately right now there’s not any regulation on it so our main focus is on DNR parameters.”
But Fisher said she doesn’t expect the subject to go away.
“It’s a new topic of conversation and it’s something we will probably plan to continue to keep an eye on,” she said.
Rios Mendoza and Fisher expressed interest in further studies of the microplastics in Lake Winnebago and other waterways, but additional research would take funding. In the meantime, Rios Mendoza urged people to find ways to use less plastic, from boycotting products with microbeads to turning down plastic bags at grocery stores.
“We need to change the culture,” Rios Mendoza said. “It’s difficult because all the time you go to the store and see plastic, plastic, plastic.”
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