Poly- and perfluorinated compounds (PFASs) are used for their anti-stick and fat-repellent properties in a variety of different products, including plastic, paper, and paperboard food contact materials (FCMs). Many of these compounds are, however, toxic, bioaccumulative, and persistent in the environment. While the production and use of perfluorooctanoic sulfonate (PFOS, CAS 1763-23-1) and perfluorooctanoic acid (PFOA, CAS 335-67-1) has been declining due to regulatory restrictions and/or voluntary phase-out by industry, other PFASs, for example fluorotelomer alcohols (FTOHs) and polyfluoroalkyl phosphate esters (PAPs), continue to be used (see FPF background article).
A study by Guanxiang Yuan and colleagues from the College of Urban and Environmental Sciences, Peking University, Beijing, China, published on December 11, 2015 in the peer-reviewed journal Environmental Science & Technology, reported on the levels of various FTOHs in paper food contact articles obtained in China (69 samples) and the U.S. (25 samples). Both short- and long-chain FTOHs were detected, the latter identified in FCMs for the first time and with relatively high concentrations (up to 8,450 ng/g for 12:2 FTOH).
The median concentration of total FTOHs in Chinese ‘eco-friendly’ tableware made of sugar cane and reed pulp fiber was 2,990 ng/g. This is lower than in popcorn bags (18,200 ng/g), but higher than in other FCMs tested (<0.55-38.7 ng/g). Among the U.S. paper tableware samples, FTOH concentration was also highest in the single sample of ‘eco-friendly’ paper product (499 ng/g), with samples made of ivory board [clay-coated cardboard] or plastic showing much lower FTOH levels (<0.55-2.97 ng/g). These findings demonstrate that an assessment of the ‘eco-friendliness’ of a particular FCM should take into account not only the primary constituent (FPF reported), but also the multitude of all other chemicals added to the product.
For migration tests, the authors used a setup expected to closely resemble the real use conditions: Food simulants were preheated to 100°C and placed in contact with a paper bowl for 15 minutes at room temperature. With this setup, a significant migration could be demonstrated for all food simulants used, with migration efficiencies reaching up to 0.24% in water and 10% ethanol, 2.79% in 30% ethanol, 13.0% in 50% ethanol, and 2.28% in oil.
Both FTOH and PAPs in rodents were shown to be biotransformed into perfluoroalkyl carboxylic acids (PFCAs), like for example PFOA. Therefore, these compounds are suspected to contribute to internal levels of PFCAs in people. A study by Sonia Dagnino and colleagues from the U.S. Environmental Protection Agency (EPA), published on August 1, 2016 in the peer-reviewed journal Environmental Science & Technology, carried out a detailed characterization of FTOHs’ and PAPs’ metabolism in rats. FTOH sulfate, detectable in 5-10% of investigated human serum samples, was proposed as a biomarker of FTOH and PAP exposure in humans.
Yuan, G. et al. (2016). “Ubiquitous occurrence of fluorotelomer alcohols in eco-friendly paper-made food-contact materials and their implication for human exposure.” Environmental Science & Technology 50(2): 942-950.
Dagnino, S. et al. (2016). “Identification of biomarkers of exposure to FTOHs and PAPs in humans using a targeted and non-targeted analysis approach.” Environmental Science & Technology (published online August 1, 2016).