In a perspective article published on August 2, 2022, in the journal Environmental Science & Technology, Ian T. Cousins and co-authors from Stockholm University and ETH Zurich, hypothesized that per- and polyfluoroalkyl (PFAS) in the environment represent a planetary boundary that has now been exceeded. To test their hypothesis, Cousins et al. compared levels of PFAS measured in rainwater, surface water, and soils with guideline values. Specifically, they looked at the perfluoroalkyl acids (PFAAs), including perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane-sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA).
Based on the calculations for these four PFAA, Cousins and co-authors concluded that “PFAS define a new planetary boundary that has been exceeded, based on PFAS levels in environmental media being ubiquitously above guideline levels.” For instance, concentrations of PFOA and PFOS measured in rainwater are often higher than US Environmental Protection Agency (EPA) Lifetime Drinking Water Health Advisory levels which are 0.004 ng/L for PFOA and 0.020 ng/L for PFOS. Notably, even in remote areas such as the Tibetan Plateau PFOA rainwater concentrations exceed that limit by approximately 14 times.
Although some PFAS were phased out by major manufacturers already decades ago, environmental measurements show that levels are not notably declining. The authors explain that PFAS are very persistent and will continually cycle through different environmental media and around the globe without breaking down. Cousins et al. further pointed out that with new toxicological data being published, the guidelines values for PFAS in drinking water have decreased drastically over the past 22 years as new information on the effects of PFAS comes to light. In the US, the guideline for PFOA decreased by 37.5 million times.
The authors emphasized that they only considered some of the many thousands of PFAS, most of which have yet unknown risks. Therefore problems associated with PFAS are likely to be much higher than evaluated in the article. Martin Scheringer, one of the co-authors of the paper, highlighted that “ now, due to the global spread of PFAS, environmental media everywhere will exceed environmental quality guidelines designed to protect human health and we can do very little to reduce the PFAS contamination. In other words, it makes sense to define a planetary boundary specifically for PFAS and, as we conclude in the paper, this boundary has now been exceeded.”
A planetary boundary is exceeded when something is ubiquitous, not easily reversible, and disrupts vital Earth systems. Chemical pollution is one of the nine originally proposed planetary boundaries which was later renamed to “novel entities” (NE) boundary. “Novel entities” include industrial chemicals and chemicals in consumer products (FPF reported). Cousins and co-authors described in their article that the NEs boundary “can be thought of as a placeholder for multiple planetary boundaries for NEs that may emerge” and argue that PFAS are only one such boundary.
Vladislav Obsekov, and co-authors from the Department of Pediatrics, NYU Grossman School of Medicine, New York, USA, also concluded that PFAS use needs to be restricted, but came to the conclusion by looking at human health outcomes. In an article published on July 26, 2022 in the journal Food Chemistry, the scientists evaluated the disease burden and costs associated with exposure to PFAS in the United States population in 2018.
For their analysis, Obsekov et al. consulted the PFAS-Tox Database that catalogs outcomes of publicly available toxicological studies on several PFAS (FPF reported), and extracted information from the primary scientific literature on PFAS published on PubMed and three scoping reviews from 2020 and 2021. They considered the 13 health outcomes for which meta-analysis of epidemiological studies demonstrated a statistically significant association between PFAS exposure and response. Health outcomes include low birth weight and childhood obesity from prenatal exposure as well as hypothyroidism, testicular and kidney cancer from lifetime exposure. To quantify exposure, the scientists used data from the US National Health and Nutrition Examination Survey (NHANES) of 2017 to 2018 (FPF reported and here). Since PFOA and PFOS are most widely studied, they focused their analysis on these PFAS members.
Obsekov and co-authors calculated the annual disease burden and associated economic costs of exposure to long-chain PFAS in the US to be at least $5.52 billion and up to $62.6 billion. Therefore, “the cost of remediation and of substituting PFAS with safer alternatives in consumer products may well be justified by the large economic costs of adverse health outcomes associated with PFAS exposure.” With costs of $17.0 billion annually, the highest costs were attributed to PFOS-related adult obesity. The researchers clarified that their “estimates are highly conservative.” Reasons for this include that they only considered health outcomes for which strong evidence existed, that they did not consider additive or synergetic effects of multiple PFAS members, and neither the social costs associated with a patient’s pain and suffering due to PFAS associated health outcomes. Although the authors find their approach to have several limitations, they think that their “models provide an approximation of the scope of the disease burden and associated costs attributable to [PFAS] exposure.” For future studies, they recommended also considering other PFAS than PFOA and PFOS as well as analyzing the probability of causation. On a general level, Obsekov et al. demonstrated “the large economic implications of regulatory inaction.”
In 2019, the Nordic Co-operation estimated the annual total health impact costs from PFAS exposure for the European Economic Area (EEA) to be between 52 and 84 billion Euro (FPF reported). Health costs have also been estimated for the exposure to endocrine-disrupting chemicals (EDCs) (FPF reported and here) as well as to phthalates (FPF reported and here).
References
Cousins, I., T. et al. (2022). “Outside the Safe Operating Space of a New Planetary Boundary for Per- and Polyfluoroalkyl Substances (PFAS).” Environmental Science & Technology. DOI: 10.1021/acs.est.2c02765
Obsekov, V. et al. (2022). “Leveraging Systematic Reviews to Explore Disease Burden and Costs of Per‑ and Polyfluoroalkyl Substance Exposures in the United States.” Exposure and Health. DOI: 10.1007/s12403-022-00496-y
