Alarming levels of PFAS in US freshwater fish, study finds

A group of researchers from Duke University (US) has recently published a review of contaminant testing data from across the United States showing that so-called “forever chemicals” (PFAS) have been widely detected in freshwater fish.  

PFAS, i.e. perfluoroalkyl substances, are a group of over 1 800 compounds present in hundreds of products, which do not degrade in nature or in the human body and therefore tend to accumulate (hence their name “forever chemicals”).
This family of chemicals is the subject of intense health study and exposure has already been linked to illnesses such as cancer, thyroid and liver disease, among others.  

According to the study’s findings, considering dosage calculations based on the latest EPA health guidelines for drinking water (which allow for virtually no exposure), indulging in a freshwater fish, even once, would be the equivalent of drinking water contaminated with PFOS at 48 parts-per-trillion (ppt) for a month. This would raise PFAS levels high enough in a person’s bloodstream to potentially endanger their health.  

The results of this study are based on 500 freshwater fish samples, taken from 1 968 fishes collected between 2013 and 2015, as part of two monitoring programs of the Environmental Protection Agency (EPA).    

Thirteen different PFAS chemicals have been measured on 44 different fish species. The most frequently (74%) detected compound was PFOS.  

44% of sampled fish tested between 1 and 10 ppb for PFAS, and another 45% tested between 10 and 50 ppb. The highest result was 286 ppb. PFAS levels differed by location, with average values in fish caught in urban areas about 2.7 times higher than those collected from remote water bodies.  

The median levels of total detected PFAS in freshwater fish across the United States were 278 times higher than levels in commercially relevant fish tested by the U.S. Food and Drug Administration in 2019–2022. The authors acknowledge that a lack of recent fish testing data could have resulted in an overestimation of the current exposure levels. In fact, median PFOS levels in fish collected through EPA sampling in 2008 and 2009 were 30% higher than the 2013 to 2015 collection data and chemical levels may have continued to decline since then.  

Concern on this matter is high also in Europe. Recently, the health and food safety agencies of Germany, the Netherlands, Denmark, Norway and Sweden, in a joint action, following studies conducted over the past three years, have asked the European Chemicals Agency (ECHA) to introduce much more restrictive limits than the current ones on the maximum concentrations of PFAS tolerated for any type of use.    

As stated in the press release of the German Federal Institute for Risk Assessment (BfR), the aim is to set the thresholds to be included in the updates of the REACH Regulation, the list that came into force in 2007, which regulates thousands of chemical substances. The requests will be formalized in February, and it will be the subject of discussion for the following 12 months, after which the definitive version of the document should be drafted and then sent to the European Commission, which will decide on the matter.