Several scientific articles published in between June and August 2023, investigated the presence of per- and polyfluoroalkyl substances (PFAS) in a variety of food contact materials (FCMs), their migration from FCM, their presence in different types of foods, and the environment, as well as potential effects on child health.
Measuring PFAS in food contact articles
In an article published on August 4, 2023, in the journal Chemosphere, María Jesús Dueñas -Mas from the University of Córdoba, Spain, and co-authors quantified PFAS in 47 food contact articles (FCAs) collected from 17 French fast-food restaurants between September and November 2021. Samples were made of paper or cardboard and included cups, plates, wrapping papers, boxes, filters, beakers, and trays.
The researchers extracted the samples in methanol and sonication at room temperature for 30 min and by repeating it two times. Extracts were applied to liquid chromatography-mass spectrometry (LC-MS/MS) and investigated for different groups of PFAS, perfluorocarboxylic acids (PFCAs; n = 16), perfluorosulfonic acids (PFSAs; n = 14), as well as sulfonamides (n = 5) and fluorotelomer phosphate esters (PAPs; n = 5).
The authors reported three PFAS to be present in all analyzed samples: perfluorohexanoic acid (PFHxA), 6:2 fluorotelomer sulfonic acid (6:2 FTS), and 6:2/6:2 fluorotelomer phosphate diester (6:2/6:2 diPAP, CAS 57677-95-9), while only two analytes were not detected in any sample. Comparing the different groups, PAPs were detected most frequently (in 68 -89% of the samples) and in the highest concentrations which were <0.006–42.7 n/ g for fluorotelomer phosphate monoester (4:2 monoPAP, CAS 150065-76-2), <0.001–2.7 ng/g for 8:2 fluorotelomer phosphate monoester (8:2 monoPAP) and <0.001–287 ng/g for 8:2/8:2 fluorotelomer phosphate diester (8:2/8:2 diPAP, CAS 678-41-1).
Concerning PFCAs, short-chain variants (C4-C6) were found in higher concentration than medium (C7-C11) and long-chain variants (C11-C18) but were detected less often. The most detected substances in the PFSA group with detection frequencies between 70 and 98% were perfluorobutane sulfonic acid (PFBS, CAS 375-73-5), perfluorohexane sulfonic acid (PFHxS, 355-46-4), linear and branched perfluorooctan sulfonic acid (1763-23-1), as well as 10:2 fluorotelomer sulfonic acid (10:2 FTS, CAS 120226-60-0).
Paula Vera from the University of Zaragosa and co-authors also studied PFAS in FCMs. In contrast to Dueñas-Mas et al. who performed extraction experiments and targeted the compounds present in FCAs, Vera et al targeted substances migrating from 12 trays made of cardboard, recycled cardboard, sugar cane, starch, or paper, as well as an additional, 13th, sample of Teflon coating. In their article published on July 28, 2023, in the journal Talanta, the scientists describe that they focused on FCMs for baked products which were water-repellant and oleophobic coated and originated from China or Spain.
Migration experiments were performed with Tenax® as a simulant for solid foods under 40 °C for 3 days. Teflon-coated samples were also left to migrate for 5 min at 175 °C. Using ultrahigh performance liquid chromatography (UPLC) coupled with ion-mobility (IMS) quadrupole-time-of-flight (QTOF) mass spectrometry, the migrants were investigated for PFAS.
The authors detected a total of eleven PFAS in the samples from China in concentrations between 3.2 and 22.3 µg/kg packaging, while only two substances in very low levels were detected in the samples from Spain. The eleven PFAS belong to the group of perfluorocarboxylic acids (PFCAs), perfluorosulfonic acid (PFSAs), and perfluorooctanesulfonamidoacetic acid substances (FOSAAs). Migration was highest for PFOA while the migration of the other PFAS decreased with increasing chain length. From all 12 investigated trays, PFOA and its salts migrated in levels lower than 0.025 mg/kg making them suitable for use in food contact since lower than the limit of 1 mg/kg for PFOA-related compounds set by the Regulation (EU) 2020/784 (FPF reported).
About the detection method, Vera and co-authors find the UPLC-IMS-QTOF system “a powerful tool, enabling the creation of a PFAS target list with collision cross section (CCS) values for subsequent screening analysis. The addition of CCS as a screening parameter increases the levels of confidence in the compound assignments and reduces the number of false positives, thereby enabling increased accuracy in quantitation.”
In an article published on August 24, 2023, in the journal Food Additives & Contaminants: Part A, Pauline Boisacq from the University of Antwerp, Belgium, and co-authors investigated PFAS in 29 brands of straws available on the Belgian market. The straws were made of polylactic acid (PLA) plastic, paper, bamboo, glass, or stainless steel, cut/broken into pieces, and extracted with methanol. Applying them to ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and UHPLC-QTOF, the scientists screened them for the presence of 29 PFAS as well as suspects of PFAS, respectively.
Boisacq and co-authors detected PFAS in all types of straws except those made of stainless steel. PFAS assessed by targeted analysis were found in almost all paper-based straws (in levels up to 7.15 ng/g), four out of five bamboo straws (up to 3.47 ng/g), two out of four glass straws (up to 6.65 ng/g), and three out of four plastic straw brands (up to 0.924 ng/g). In the suspect screening, the researchers identified additional PFAS such as trifluoroacetic acid (TFA, CAS 76-05-1) and trifluoromethanesulfonic acid (TFMS, CAS 1493-13-6).
The authors concluded that “‘eco-friendly’ plant-based [made of paper or bamboo] straws are not necessarily a more sustainable alternative to plastic straws” while “the most sustainable alternative seems to be stainless-steel straws, which can be reused, do not contain PFAS and can be fully recycled.” Straws based on paper or other materials have replaced plastic straws in many parts of the world. However, also to these alternative materials, PFAS may be added to make them water-repellent.
An additional concern with plant-based or other food service ware labeled as “compostable” is the potential for PFAS to contaminate the environment via compost. Caleb P. Goossen from Maine Organic Farmers and Gardeners Association, US, and co-authors detailed their investigation into compost contaminating in an article published on June 6, 2023, in the journal Biointerphases. They analyzed three samples of finished compost made from products labeled “compostable” and manure and detected at least 12 of the targeted 28 PFAS. The total concentration of PFAS ranged from 209 to 455 µg/kg. Comparing the results to those samples containing manure only, showed that the latter only contained PFOS (3.7 µg/kg). Grossen and co-authors concluded that compostable service ware will likely lead to the contamination of the finished compost with PFAS which “threatens surrounding groundwater and surface waters, in addition to increasing potential crop uptake.” The authors clarified that their study wasn’t designed for robust statistical analysis but rather thought to be an initial starting point for further studies.
Measuring PFAS in foods and drinking water
Yingyi Han and Xueli Cao from Beijing Technology and Business University, China, reviewed PFAS in edible oil providing an overview of concentrations, their measurement, and potential sources. In their article published on July 6, 2023, in the journal Foods, they describe that they searched Web of Science for the relevant literature published in the last 20 years.
The authors point out a diversity of sources of PFAS in edible oils. For example, the grinding machine used in oil processing can be made out of plastic containing PFAS or contaminated with the substances present in detergents and lubricants. Furthermore, they emphasized the migration of PFAS from FCMs (FPF reported and here) taking place in two different ways. PFAS could migrate from plastic or paper packaging during storage and transportation (FPF reported), or from fluorocarbon resin-coated frying pans, baking utensils, and non-stick baking papers used to heat foodstuff by adding edible oil (FPF reported).
Han and Cao highlighted 15 studies that have measured PFAS in edible oils separating their results by country and type of oil. This showed that PFAS are present in edible oil worldwide with C6-C10 perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs) being “extensively present” while only a few studies looked at short-chain PFAS and non-ionic PFAS (perfluoroalkyl iodides; PFAIs). Besides more research on the latter, the authors called for “faster, simpler, and more effective analytical methods” for PFAS investigation as well as the assessment of human exposure levels which are safe.
Humans are not only exposed to PFAS through packaged food and beverages but also through drinking water. For instance, PFAS may be released from water pipes (FPF reported). In a review article published on August 24, 2023, in the journal Npj clean water, Sze Yee Wee & Ahmad Zaharin Aris from the Universiti Putra Malaysia, Serdang, discuss practices to monitor and manage PFAS in the environment with a focus on PFOA and PFOS which are most frequently detected in the environment. The authors emphasized that opposed to developed countries, developing and underdeveloped countries “often lack regulations and mechanisms to address emerging PFAS.”
As a consequence of the release of PFAS into the environment and their persistence, PFAS are widespread across the world (FPF reported) and their concentrations have exceeded the planetary boundary for chemical pollution (FPF reported).
Health effects caused by PFAS
In a review article published on July 29, 2023, in the journal Chemical Engineering Journal, Karuna Singh from the National Institute of Technology Delhi, India, and co-authors focus on PFAS in Asia. As Wee and Aris, Singh and co-authors explained that in most low- and middle-income countries, such as those in Asia, regulations are lacking. Given a population of over 4.6 billion in Asia and the growing demand for PFAS they stated that “this region faces much higher risk from these chemicals compared to the Western world.” In their review, they discussed the different types of PFAS, their occurrence in the environment with a focus on Asian countries, human exposure and health consequences separating between maternal effects, those to newborn and child health, cardiometabolic effects, effects on the immune system, on neurodevelopment, and cancer. They further summarized current regulations and guidelines as well as technologies to remediate different environmental matrices from PFAS.
Claire Philippat from the University Grenoble Alpes, France, and co-authors were interested in the effects of PFAS on children’s respiratory health. In their article published on July 3, 2023, in the journal Environmental Research, they described that they based their investigation on 433 mother-child pairs from the SEPAGES mother-child cohort (2014–2017, Grenoble, France). The scientists collected maternal blood during pregnancy and tested the lung function of their child at the age of two or 36 months or the history of respiratory diseases in the first 36 months.
Assessing 13 PFAS, they detected seven in 98 – 100% of the samples and the other six in less than 70% of the samples. The researchers evaluated 13 more PFAS but excluded them due to low quantification. Asking for respiratory health diseases in the children, “14% of the parents reported that their child ever had asthma, 34% ever had wheeze, 38% had bronchiolitis and 21% had bronchitis.”
Clustering exposures in the low, moderate group, and high, 163 children were found in the low group (“5-21% of the mothers of this group had a concentration above the whole population median concentration”), 236 in the moderate group (60-70%), and 51 children in the high PFAS concentration group (76-96%). Correlating exposure groups and lung function showed that children in the moderate exposure group had better lung function than those in the low exposure group indicating no “deleterious effect of prenatal PFAS exposure on respiratory health at an early age.”
Previous research found that breast milk is major source of exposure to PFAS for infants (FPF reported) and linked this exposure to illness of children (FPF reported).
References
Boisacq, P. et al. (2023). “Assessment of poly- and perfluoroalkyl substances (PFAS) in commercially available drinking straws using targeted and suspect screening approaches.” Food Additives & Contaminants: Part A. DOI: 10.1080/19440049.2023.2240908
Dueñas-Mas, M. J. et al. (2023). ”Determination of several PFAS groups in food packaging material from fast-food restaurants in France.” Chemosphere. DOI: 10.1016/j.chemosphere.2023.139734
Goossen, C. P. et al. (2023). “Evidence of compost contamination with per- and polyfluoroalkyl substances (PFAS) from “compostable” food serviceware.” Biointerphases. DOI: 10.1116/6.0002746
Han, Y. & Cao, X. (2023). “Research Progress of Perfluoroalkyl Substances in Edible Oil—A Review.” Foods. DOI: 10.3390/foods12132624
Philippat, C. et al. (2023). “In utero exposure to poly- and perfluoroalkyl substances and children respiratory health in the three first years of life.” Environmental Research. DOI: 10.1016/j.envres.2023.116544
Singh, K. et al. (2023). “Per-and polyfluoroalkyl substances (PFAS) as a health hazard: Current state of knowledge and strategies in environmental settings across Asia and future perspectives.” Chemical Engineering Journal. DOI: 10.1016/j.cej.2023.145064
Vera, P. et al. (2023). “The analysis of the migration of per and poly fluoroalkyl substances (PFAS) from food contact materials using ultrahigh performance liquid chromatography coupled to ion-mobility quadrupole time-of-flight mass spectrometry (UPLC- IMS-QTOF).” Talanta. DOI: 10.1016/j.talanta.2023.124999
Wee, S. Y. & Aris, A. Z. (2023). “Revisiting the “forever chemicals”, PFOA and PFOS exposure in drinking water.” Npj Clean Water. DOI: 10.1038/s41545-023-00274-6
