Sait Serkan Gurbuz/AP Photo Rep. Rashida Tlaib, D-Mich., listesn during a House Oversight and Reform subcommittee hearing on PFAS chemicals and their risks on Wednesday, March 6, 2019, on Capitol Hill in Washington.

HOUGHTON — The Wisconsin Department of Natural Resources (WDNR) last week notified the Michigan Department of Health and Human Services (MDHHS) of elevated perfluorooctane sulfonate (PFOS) levels in Lake Superior rainbow smelt.

PFAS, Per — and polyfluoroalkyl substances — are a diverse group of human-made chemicals used in a wide range of consumer and industrial products. Some PFAS have been more widely used and studied than others. Many PFAS are resistant to grease, oil, water, and heat.

PFAS and PFOS are referred to as “forever chemicals,” the Midwestern Environmental Advocates reported in the fall of 2020, because they accumulate over time in the human body, and do not break down easily due to a long half-life, rendering them dangerous to both humans and the environment, even in low concentrations.

PFOS and PFAS are water and stain-resistant synthetic compounds that are difficult to break down in the environment and in the human body. The National Wildlife Federation reports that they are also used in baby products–baby mats, pads, blankets, and bibs. They are also used in outdoor clothing, including rain jackets, snowsuits and winter gloves, as well as in bed linens, carpets, footwear, non-stick pots and pans, toothpaste and dental floss, and other personal care products. PFASs are also used extensively in firefighting foam, with use at military bases, airports, and petroleum refineries

According to the Centers for Disease Control and Prevention (CDC), estimates of more than 95% percent of Americans have PFAs in their bodies. PFAS exposure has been linked to an increase in risk of various health problems such as increased cancer risk, reproductive and developmental problems, high cholesterol, and ulcerative colitis.

PFOS and PFAS are no longer produced in the United States, but they are still used internationally. Exposure to PFOS and PFOA is still possible through imported goods, like carpets, leather and apparel, textiles, paper and packaging, coatings, rubber and plastics. PFAS are resilient and can still be found in contaminated soil and water.

In an effort to reduce PFAS exposure from imported goods, Canada prohibited the use, sale and import of products containing PFOS in 2008. The usage of PFAS have been restricted to firefighting foams and photo ink.

 The National Wildlife Federation reported that a study in central and eastern China, in considering both air emissions and water discharges, found the majority of PFAS/PFOS releases to the environment was via direct discharges of wastewater, whether from industries or municipal wastewater treatment plants. The other major sources for PFOS were firefighting foam and pesticide application.

Smelt are not the only fish found to be contaminated by these chemicals.

In 2016, Science Direct reported that Biomonitoring programs for persistent, bioaccumulative, and/or toxic chemicals of concern in fish tissues have been operated by the governments of Canada and the United States in the Great Lakes since the 1970’s.

Lake Trout and Walleye are targeted for biomonitoring. These species are large bodied and long lived piscivorous fish, which occupy the highest trophic levels where they are found and thus tend to accumulate higher levels of persistent and bioaccumulative contaminants. These two species of fish are also valuable components of the commercial and recreational fishing industry in the Great Lakes Basin.

As far back as 2012, the Alliance for the Great Lakes reported that the chemicals enter the water via a variety of point sources — or regulated pipe discharges, and non-point sources — which are diffuse and hard to quantify. Discharges from wastewater facilities carry many pharmaceuticals and personal care product residues. Drugs that are partially metabolized by people are excreted into the municipal waste stream. A portion of the medicines that are sold go unused and may end up down the drain, as do cosmetic products, soaps and other household cleaning products. As conventional treatment is not designed to remove these types of compounds, some remain in treated wastewater at trace concentrations and enter the surface waters when the effluent is discharged into the lakes.