PFAS are a group of more than 4,700 man-made chemicals (OECD, 2018), the two most well-known of which are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS).
PFAS molecules are made up of a chain of linked carbon and fluorine atoms. The strength of the carbon-fluorine bond means these chemicals essentially do not degrade in the environment, giving them the name ‘forever chemicals’.
The forever chemical found at greatest concentrations in freshwater fish was PFOS, formerly an ingredient in 3M’s Scotchgard, averaging roughly three in four of total PFAS detections, according to new research from the US.
A new study from Environmental Working Group scientists has found eating one freshwater fish in a year equates to ingesting water with PFOS at 48 parts per trillion, or ppt, for one month. EWG found the median amounts of PFAS in freshwater fish were an astounding 280 times greater than forever chemicals detected in some commercially caught and sold fish. The testing data, from the US Environmental Protection Agency and Food and Drug Administration, showed that consuming a single meal of freshwater fish could lead to similar PFAS exposure as ingesting store-bought fish every day for a year.
“People who consume freshwater fish, especially those who catch and eat fish regularly, are at risk of alarming levels of PFAS in their bodies,” said David Andrews, Ph.D., EWG senior scientist and one of the study’s lead authors. “Growing up, I went fishing every week and ate those fish. But now when I see fish, all I think about is PFAS contamination.”
“These test results are breath taking,” said Scott Faber, EWG’s senior vice president for government affairs. “Eating one bass is equivalent to drinking PFOS-tainted water for a month.”
PFAS disposal methods may lead to greater pollution
The researchers analyzed data from more than 500 samples of fish filets collected in the US from 2013 to 2015 under monitoring programs by the EPA, the National Rivers and Streams Assessment and the Great Lakes Human Health Fish Fillet Tissue Study. The median level of total PFAS in fish filets was 9,500 nanograms per kilogram, with a median level of 11,800 nanograms per kilogram in the Great Lakes.
"The extent that PFAS has contaminated fish is staggering,” stressed Nadia Barbo, a graduate student at Duke University and lead researcher on this project.
The researchers linked PFAS pollution to environmental injustice, noting that freshwater fish are an important source of protein for many people, and PFAS contamination threatens those who cannot afford to purchase commercial seafood. Communities that depend on fishing for sustenance and for traditional cultural practices are ‘inordinately harmed’, they argued.
“Identifying sources of PFAS exposure is an urgent public health priority,” argued Tasha Stoiber, Ph.D., an EWG senior scientist and another co-author.
“PFAS do not disappear when products are thrown or flushed away. Our research shows that the most common disposal methods may end up leading to further environmental pollution,” she warned.
To combat this, EWG would like to see an end to industrial discharges of PFAS, highlighting that these chemicals originate from ‘tens of thousands’ of manufacturing facilities, municipal landfills and wastewater treatment plants, airports, and sites where PFAS-containing firefighting foams have been used.
This contamination of water has spread PFAS to soil, crops and wildlife, including fish.
“For decades, polluters have dumped as much PFAS as they wanted into our rivers, streams, lakes and bays with impunity. We must turn off the tap of PFAS pollution from industrial discharges, which affect more and more Americans every day,” said EWG’s Faber.
Broad range of health risks
People are exposed to PFAS through contaminated drinking water, food and packaging. According to a 2019 briefing from the European Environment Agency on emerging chemical risks in the region, PFAS pollution is ‘widespread in Europe’.
PFAS build up in our bodies and never break down in the environment. A growing body of scientific evidence points to potential adverse health impacts associated with PFAS exposure, including liver damage, thyroid disease, high cholesterol, obesity, hormone suppression and increased risk of certain cancers. Very low doses of PFAS in drinking water have been linked to suppression of the immune system, including reduced vaccine efficacy, and PFAS has also been linked to reproductive and developmental problems.
‘Locally caught freshwater fish across the United States are likely a significant source of exposure to PFOS and other perfluorinated compounds’