Environmental Science and Technology Journal

Lake and river foams study reveals high PFAS levels, even though underlying water may be less contaminated

On: July 9, 2024

In: Christy Remucal, Doug Bach, Edward Kostelnik, Environmental Science and Technology Journal, Kaitlyn Gruber, Lake Monona, PFAS in lake foam, PFOS, Sarah Balgooyen, Summer Sherman-Bertinetti, University of Wisconsin-Madison, Wisconsin Department of Natural Resources, Wisconsin lake foam has PFAS

Foam on Lake Monona. Image credit: Doug Bach

A new study of natural foams and water surface microlayers of 43 Wisconsin rivers and lakes quantified 36 compounds in a group of chemicals known as PFAS. While PFAS were detected in both types of samples, it is the foams that the researcher said were “orders of magnitude higher in PFAS concentration compared to water,” while urging people and their pets to avoid them. The study also revealed that foams, generally off-white and found along shorelines on windy days, are not an indicator of elevated contamination levels in the entire water body.

“We studied many different lakes and found PFAS in all of them. The PFAS concentrations were high in the foams even if the concentrations in the water were relatively low,” said Christy Remucal with the University of Wisconsin–Madison Department of Civil and Environmental Engineering and interim director of the University of Wisconsin Aquatic Sciences Center.

Remucal stressed the need to avoid the foams because of the contaminants’ warning-worthy levels. “The chemical we found most in the foam is PFOS, which is one of the chemicals that’s driving fish advisories and driving drinking water regulations,” she said. “The highest PFOS concentrations we measured in foam were almost 300,000 nanograms per liter and, for comparison, the federal drinking water regulation is 4 nanograms per liter.”

She continued, “The main way people are exposed to PFAS is through ingestion…Obviously, people aren’t drinking foam. I would be more concerned about, for example, a kid who plays in the foam and then goes to grab a handful of snacks. You could potentially have some oral exposure that way.”

There are more than 9,000 PFAS compounds, which are often referred to as “forever chemicals” because they do not readily break down in the environment. For decades, they have been used to make a wide range of products resistant to water, grease, oil and stains and are also found in firefighting foams, which are a major source of environmental PFAS contamination. PFAS have been shown to have adverse effects on human health and higher incidence of cancer.

The levels in the new study validate a current Wisconsin Department of Natural Resources warning, as well as a similar freshwater foam warning in Michigan and one for saltwater foam in the Netherlands. They are timely cautions as spring and summer come to Wisconsin and people and their pets spend more time hiking along open water or engaging in paddle sports and swimming where foams can be found.

Remucal, postdoctoral co-investigators Summer Sherman-Bertinetti and Sarah Balgooyen and graduate students Kaitlyn Gruber and Edward Kostelnik published their work in the journal “Environmental Science & Technology.” It was funded by a grant from the Wisconsin Sea Grant College Program.

Christy Remucal and Sarah Balgooyen work with PFAS samples in the lab. Image credit: Wisconsin Sea Grant

Integral to the study were dozens of citizen volunteers who alerted the research team to the presence of foams. This was critical, Remucal said, because sampling was opportunistic—foams are fleeting, stirred up by wind and mixing with water, they can dissipate as quickly as they appear.

She also credited the Wisconsin Department of Natural Resources with assistance in foam sightings.

The work also illuminates the efforts of other research groups exploring a possible path of PFAS cleanup. Because PFAS are surfactants, which means they are drawn to the air and water interface, they may move out of the water below and toward the bubbles in foam. When concentrated like this, the contaminants could be removed.

Remucal and her team also looked at water surface microlayers and found PFAS levels were slightly higher than underlying water but that the bigger take-away message remains the contaminant level in foams. She was pleased they explored the microlayers question, though, because the air and water interface dictates how PFAS move in groundwater. Now, the science community has an understanding of how PFAS movement in surface water compares to their movement in groundwater.

The post Lake and river foams study reveals high PFAS levels, even though underlying water may be less contaminated first appeared on Wisconsin Sea Grant.

Original Article

News Releases | Wisconsin Sea Grant

https://www.seagrant.wisc.edu/news/lake-and-river-foams-study-reveals-high-pfas-levels-even-though-underlying-water-may-be-less-contaminated/

Moira Harrington

Methylmercury water concentrations low, but Great Lakes fish consumption advisories persist—new research documents one probable culprit

On: September 22, 2021

In: Environmental Science and Technology Journal, fish consumption advisories, mercury, methylmercury, Ryan Lepak

Methylmercury uptake rate in phytoplankton is among the highest recorded

Sept. 22, 2021
By Moira Harrington

A recently published study in the journal of the American Chemical Society, Environmental Science and Technology, found that while Great Lakes waters harbor low methylmercury concentrations, the rates of methylmercury transfer to phytoplankton are extremely high, higher than rates observed in open oceans. Phytoplankton are the smallest organisms in an aquatic food web.

Researchers, including a UW-Madison-supported postdoctoral scientist, say this is important because the bioaccumulation of methylmercury into phytoplankton sets the baseline for methylmercury levels in fish.

Methylmercury is highly toxic and is the form most encountered by people. This is generally through eating fish and shellfish, which is why advisory consumption guidelines are issued, particularly targeted toward pregnant women and young children. However, monitoring fish and shellfish varieties—some have higher levels of methylmercury—and consumption frequency, people can still enjoy the health benefits of omega-3 fatty acids found in the food.

From 2010 to 2018, the U.S. Geological Survey Mercury Research Lab in Madison, Wisconsin, teamed up with the U.S. EPA and its research vessel the Lake Guardian to monitor inorganic and methylmercury dynamics in the five Great Lakes. This was done through a combination of vertically, seasonally and spatially comprehensive water quality measurements and analysis of seston collections, which is the suspended particle mass in the lakes made up of plankton, bacteria, bugs and detritus.

Ryan Lepak, a postdoctoral scientist (Ph.D. UW-Madison, 2018) through the University of Wisconsin Water Resources Institute and its sister organization, Sea Grant and stationed at the U.S. EPA Mid-Continent Ecology Division in Duluth, Minnesota, said, “Ultimately, the study concluded the very low concentrations of dissolved organic carbon, the substrate which competes with phytoplankton for methylmercury but also can serve as a source of sustenance, in these lakes likely create a scenario where methylmercury transfer to phytoplankton is facilitated. The planktonic methylmercury levels are quite low, but exceedingly higher than we’d expect considering the extremely low methylmercury levels in the waters in which they reside.”

Ryan Lepak aboard the U.S. EPA RV Lake Guardian sampling for methylmercury. Contributed photo.

Lepak continued by explaining the transfer of methylmercury up the lower food web, from phytoplankton to herbivorous zooplankton and then to omnivorous zooplankton, was not statistically different. Finally, he and the team tested whether water-mercury concentrations have declined over the study period and determined that without more routine continuous monitoring, trends could not be identified because unresolved sources of variability masked data trends.

“The conditions that make the Great Lakes highly susceptible to methylmercury bioaccumulation are common to the world’s great lakes,” Lepak said. “These global water bodies should serve as excellent sentinels to track the impacts mercury reductions at local, regional and global scales have on biota. This paper’s important finding could aid those planning global mercury monitoring networks aimed at tracking mercury reductions due to actions resulting from the Minamata Convention on Mercury, a multilateral environmental agreement the U.S. signed in 2013 and which would reduce global mercury pollution.”

The post Methylmercury water concentrations low, but Great Lakes fish consumption advisories persist—new research documents one probable culprit first appeared on WRI.

Original Article

News Release | WRI

https://www.wri.wisc.edu/news/methylmercury-water-concentrations-low-but-great-lakes-fish-consumption-advisories-persist-new-research-documents-one-probable-culprit/

Moira Harrington