PFAS, or Per- and Polyfluoroalkyl Substances, are a group of widely-used chemicals found in everything from pots and pans to food wrappers, dental floss and firefighting foams. Manufactured by chemical companies since the 1940s, PFAS molecules are made up of a chain of carbon and fluorine atoms linked together. Remucal notes the carbon-fluorine bond is one of the strongest bonds in existence.“There aren’t any known natural processes that break down these chemicals. There is no known biodegradation process at all,” she says.
No one knows for sure exactly how many different types of PFAS compounds are out there – some estimates put the number at around 6,000. Two of the first types ever created, PFOA and PFOS, have been discontinued from use in the United States amid concern over potential health impacts from high-level exposure. But because they don’t break down, you can find trace amounts of the chemicals just about everywhere, including in the blood streams of most people. “You look at something like PFOS and an environmental chemist will tell you that it’s going to be bad news,” says Remucal. “You can find these chemicals in something like 98 to 99 percent of Americans.”
Remucal’s research focuses on contamination in and around Marinette, Wis., where industrial wastewater leaving the Tyco fire products plant has contaminated streams, sediment, soil and groundwater. Some nearby private drinking water wells have shown combined PFOA and PFOS concentrations of 73 to 1,900 parts per trillion (ppt) – above both the EPA Health Advisory Level (70 ppt) and Wisconsin Department of Health Services recommended groundwater standard (20 ppt).
“We wanted to take a look at what this contamination means for the surface water … The first phase is focusing right in the Marinette and Peshtigo areas, sampling rivers and tributaries – the water and sediment,” Remucal explains. “The goal is to find out how much of the chemicals stick to the sediment versus staying in the water. Then we want to move a little bit bigger and go out on Green Bay and Lake Michigan and look at both water and sediment again, but on a really big body of water.”
PFAS molecules have a dual nature, they are both hydrophobic (water repellent) and hydrophilic (attracted to water), which makes it difficult to predict how they will move in the environment. “They’re weird. And that’s what makes them so attractive for industrial applications. This part repels water and this part repels oil, and that’s why we use them so much. But it makes predicting their fate challenging, because they don’t always behave the way we think they ought to,” Remucal says.