Assessing potential human health and ecological implications of PFAS from leave-in dental products.

Contaminated water and food are the main sources of documented per- and polyfluoroalkyl substances (PFAS) exposure in humans. However, other sources may contribute to the overall PFAS intake. While several studies documented the presence of PFAS in consumer products, PFAS evaluation in dental products has been limited to floss and tape to date. This study estimated PFAS exposures from a convenience sample of leave-in dental products (night guards and whitening trays), which remain in contact with the mouth for longer durations than previously evaluated dental products. This analysis evaluated whether consumer usage of these dental products meaningfully contributes to oral exposure of PFAS. Leaching of PFAS upon disposal of products was also considered. Out of 24 PFAS measured, perfluorobutanoic acid (PFBA; 3.24-4.17 ng/product or 0.67-0.83 ng/g) and perfluorooctanesulfonic acid (PFOS; 7.25-16.45 ng/product or 1.2-2.3 ng/g) were detected in night guards, and no PFAS were detected in whitening trays. Non-targeted analysis showed additional possible PFAS, which could not be characterized. The findings showed that PFOS and/or PFBA present in night guards were unlikely to pose a health concern. From an ecological perspective, the dental products examined were shown to constitute a negligible contribution to environmental PFAS. In conclusion, the examined dental products do not represent a significant source of exposure to PFAS for humans or the environment. The study demonstrates how risk assessment can be integrated by the industry into product stewardship programs to evaluate the potential health and environmental impacts of chemicals in consumer products.

70 analyte PFAS test method highlights need for expanded testing of PFAS in drinking water.

In this community-led pilot study we sought to investigate the utility of expanded per- and polyfluoroalkyl substances (PFAS) testing for drinking water, using a targeted analysis for 70 PFAS and the Total Oxidizable Precursor (TOP) Assay which can indicate the presence of precursor PFAS. PFAS were detected in 30 out of 44 drinking water samples across 16 states; 15 samples would exceed US EPA's proposed maximum contaminant levels for six PFAS. Twenty-six unique PFAS were identified, including 12 not covered by either US EPA Methods 537.1 or 533. An ultrashort chain PFAS, PFPrA, had the highest frequency of detection, occurring in 24 of 30 samples. It was also the PFAS reported at the highest concentration in 15 of these samples. We created a data filter to model how these samples would be reported under the upcoming fifth Unregulated Contaminant Monitoring Rule (UCMR5) requirements. All of the 30 samples with PFAS quantified by the 70 PFAS test had one or more PFAS present that would not be captured if the UCMR5 reporting requirements were followed. Our analysis suggests the upcoming UCMR5 will likely underreport PFAS in drinking water, due to limited coverage and higher minimum reporting limits. Results were inconclusive on the utility of the TOP Assay for monitoring drinking water. The results from this study provide important information to community participants regarding their current PFAS drinking water exposure. In addition, these results suggest gaps that need to be addressed by regulatory and scientific communities, in particular, the need for expanded targeted analysis of PFAS, the development of a sensitive, broad spectrum PFAS test, and further investigation into ultrashort chain PFAS.