On September 23, 2020, researchers from the University of Iowa published an article in the peer-reviewed journal Integrated Environmental Assessment and Management investigating the concentrations of non-intentionally added perfluorocarboxylic acids (PFCAs) in recycled paper packaging materials. Using contact angle measurements of droplets on the materials’ surface, the authors identified concentration thresholds that defined the limit of performance (LOP) for each of the four PFCAs, C4 (perfluorobutyric acid (PFBA), CAS 375-22-4), C6 (perfluorohexanoic acid (PFHxA), CAS 307-24-4), C8 (perfluorooctanoic acid (PFOA), CAS 335-67-1), and C10 (perfluorodecanoic acid (PFDA), CAS 335-76-2). The LOP thresholds were set below concentrations needed to provide grease and water repelling performance enhancements. In this way, because PFCAs’ presence below these thresholds provides no practical advantage, their detection at concentrations below the LOP values can be assumed to be due to non‐intentional carry-over from recycled fibers rather than their intentional addition. Thus, PFCAs present at concentrations lower than the LOP thresholds can be regarded as non-intentionally added substances (NIAS).
The study determined a range of thresholds varying from 37 ppm for C10 PFCA to 1,238 ppm for C4 PFCA. It explains that this information is “critical for understanding what concentrations of PFCAs in food packaging can be considered intentionally added for regulatory compliance.” Through additional research, the study’s authors plan to expand the test method to also develop NIAS concentration thresholds for fluorotelomer, sulfonamide, and fluoropolymer substances.
PFCAs are members of the larger class of per- and polyfluoroalkyl substances (PFAS). They can be added within surface treatments to paper and board food packaging to provide water and grease resistance. A recent report by the OECD investigated non-fluorinated treatment alternatives for food packaging and found that such products are widely available and effective (FPF reported).
Curtzwiler, G. et al. (September 2020). “Significance of Perfluoroalkyl Substances (PFAS) in Food Packaging.” Integrated Environmental Assessment and Management