Finger Lickin’ Fluoroalkyls
PIGE spectroscopy tracks the ecotoxic compounds in our fast food wrappers
Joanna Cummings |
Fancy your fried chicken wrap with a side of perfluorinated compounds? When you order fast food, you may be getting a little more than you bargained for – namely, per- and poly-fluoroalkyl substances (PFASs). PFASs are used to render packaging and textiles water and stain resistant. They are also used in a variety of specialty surfactant applications, notably as a primary ingredient in the aqueous film-forming foams (AFFF) used in jet-fuel fire-fighting foams. In food packaging, they are added to prevent water and oil from seeping through paper or cardboard. But how much of them make it into our bodies – and what impact would they have on our health?
Researchers from the University of Notre Dame have analyzed over 400 samples of food packaging for the presence of fluorine and other chemicals, using particle induced gamma-ray emission (PIGE) spectroscopy. “The method is relatively free of matrix effects because gamma rays are very penetrating, and there are no spectral interferences from any other nuclei at these energies,” explains Graham Peaslee, Professor of Physics. They found the chemicals in 56 percent of dessert wrappers, 38 percent of burger and sandwich wrappers and 20 percent of paperboard.
The team had been working on detecting halogenated flame retardants in furniture using particle induced x-ray emission (PIXE), when a fellow researcher asked Peaslee if the technique could be used to measure fluorinated compounds. “I thought about it for a couple of weeks and realized that, though it can’t be done with PIXE, PIGE might be sensitive enough to measure it. The sensitivity of the technique for fluorine is typically in the low part-per-million range, which works well for papers and textiles that have been coated intentionally with PFASs,” Peaslee says. In previous studies on PFAS in food packaging, analysis was carried out with what Peaslee refers to as the “typical gold-standard technique” – LC-MS/MS. But using PIGE in this study allowed the team to undertake rapid screening of large numbers of samples, providing a more comprehensive assessment.
Since the paper was published, Peaslee and team have heard from several other companies interested in which wrappers were found to contain high levels of fluorine. “For most fast-food companies, the packaging is subcontracted out to a packaging provider,” Peaslee says. “My guess is that many of these companies have never asked the question of what chemicals are used on their wrappers – until now.”
PFASs are perfectly legal to use on wrappers in the US and Europe. However, Peaslee describes fluorine as a “persistent chemical”, which is absorbed into the bloodstream and accumulates over time, and notes that PFASs have previously been linked to various serious health issues, from cancers to immunotoxicity (1).
The team recently published a separate article demonstrating how a range of PFASs compounds target different organs in mice, a finding that Peaslee believes will be interesting to toxicologists both from a public health and an environmental perspective. “As more toxicology studies are performed on PFASs, we believe it is likely that all these surfactants are likely to demonstrate some ecotoxicity, especially with the extremely long environmental half-lives observed in PFASs,” says Peaslee. The team is now assessing PFAS prevalence in personal care products.
- LA Schaider et al., “Fluorinated compounds in US fast food packaging”, Environ Sci Technol Lett, 4, 105-111 (2017)