An article published on February 1, 2017 in the peer-reviewed journal Environmental Science & Technology Letters reports on the content of per- and polyfluoroalkyl substances (PFASs) in paper and paperboard packaging used for fast food in the U.S.. Laurel Schaider from the Silent Spring Institute, Newton, U.S., together with colleagues from several other U.S. institutions and non-profit organizations, measured total fluorine as a proxy for PFAS content in packaging. For this, a novel method called particle-induced γ-ray emission (PIGE) spectroscopy was used. To assess the relevance of this rapid screening technique, several samples were also analyzed for different specific PFASs using conventional targeted analysis methods. The surveyed packaging included 407 items of paper and paperboard fast food packaging collected in 2014 and 2015 in various restaurants located in five U.S. regions.
Fluorine levels above the limit of detection (LOD, 16 nmol of fluorine per cm2) were found in 33% of the surveyed packaging, reaching up to 800 nmol of fluorine per cm2. Among the different categories of surveyed food packaging, no detectable fluorine levels were found in non-food contact paper such as outer bags, paper cups for hot or cold drinks, and miscellaneous packaging such as lids and applesauce containers. Detectable fluorine levels were found in 46% of food contact paper samples (and among these, in 38% of sandwich/burger wrappers, 56% of dessert/bread wrappers, and 57% of packaging for Tex-Mex foods). Detectable fluorine was also found in 20% of food contact paperboard samples such as boxes for fries and pizza, and in 16% of milk and juice containers.
Several samples with high, low, and undetectable fluorine levels were extracted with methanol, and these extracts were analyzed for PFASs using conventional mass spectrometry-based methods. In general, fluorine content correlated with the amounts of PFAS detected. However, in some samples the amounts of PFASs measured by the targeted method could not fully explain the levels of fluorine detected. This could be due to the presence of inorganic fluorine or some unidentified non-PFAS organofluorine compounds. Alternatively, some novel PFASs could be present, which are not yet included in the targeted method, such as polyfluorinated polyether-based (PFPEs) polymers. The latter could be partially confirmed by the detection of a repeating organofluorine unit which is characteristic for these substances. However, this could also be explained by the loss of volatile PFASs, or incompatibility of some PFASs with methanol extraction procedure.
On the other hand, all samples which contained undetectable fluorine levels were found to nonetheless contain various PFASs. This demonstrates that the PIGE method may lack the necessary sensitivity to detect all PFASs present in the samples, thus the obtained prevalence values are likely to be underestimated. Indeed, the method LOD of 16 nmol of fluorine per cm2 corresponds to 30 µg of fluorine per dm2. This value is well above the limit set in 2015 by the Danish Ministry of Environment and Food (FPF reported), which is at 0.35 µg of total organic fluorine per dm2, intended to cover both intentionally added and background PFASs. Nonetheless, despite its insufficient sensitivity, the PIGE method can be used as a rapid screen to highlight the samples with the highest content of PFASs, which may be of highest concern.
Another notable finding of this study includes the detection of perfluorooctanoic acid (PFOA) in six out of 20 samples analyzed with the targeted method, even though already in 2011 U.S. manufacturers have voluntarily agreed to phase-out this and several other C8-containing PFASs from the production and use for food contact purposes. In January 2016, the U.S. Food and Drug Administration (FDA) published a final rule prohibiting the use of three related PFASs as oil and water repellents for paper and paperboard intended for food contact (FPF reported).
Furthermore, the surveyed fast food chains were found to have low awareness of PFASs in food packaging. All companies were questioned about their general policies on fluorinated products. Only two companies replied, with one stating that “they believed none of their food packaging contained fluorinated chemicals,” and the other stating that “they verified with their suppliers that their food packaging did not contain PFASs.” However, a substantial portion of food contact papers from these two chains was found to contain detectable fluorine, suggesting the presence of PFASs. This demonstrates the lack of awareness on the side of restaurant owners and/or supply chain.
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ScienceDaily (February 1, 2017). “Extensive use of fluorinated chemicals in fast food wrappers: Chemicals can leach into food.”
Emma Davies (February 2, 2017). “U.S. study highlights perfluorinated chemicals in food wrappers.” Chemical Watch
Environmental Working Group (February 3, 2017). “Warning: Food wrappers still coated in cancer-causing chemical.” EcoWatch
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Lindsey Konkel (March 29, 2017). “Did your burger come with a side of non-degrading pollutants?” Science News for Students
Schaider, L., et al. (2017). “Fluorinated compounds in U.S. fast food packaging.” Environmental Science & Technology Letters (published online February 1, 2017).