Reports of environmental and human health impacts of per‐ and polyfluoroalkyl substances (PFAS) have greatly increased in the peer‐reviewed literature. The goals of the present review are to assess the state of the science regarding toxicological effects of PFAS and to develop strategies for advancing knowledge on the health effects of this large family of chemicals. Currently, much of the toxicity data available for PFAS are for a handful of chemicals, primarily legacy PFAS such as perfluorooctanoic acid and perfluorooctane sulfonate. Epidemiological studies have revealed associations between exposure to specific PFAS and a variety of health effects, including altered immune and thyroid function, liver disease, lipid and insulin dysregulation, kidney disease, adverse reproductive and developmental outcomes, and cancer. Concordance with experimental animal data exists for many of these effects. However, information on modes of action and adverse outcome pathways must be expanded, and profound differences in PFAS toxicokinetic properties must be considered in understanding differences in responses between the sexes and among species and life stages. With many health effects noted for a relatively few example compounds and hundreds of other PFAS in commerce lacking toxicity data, more contemporary and high‐throughput approaches such as read‐across, molecular dynamics, and protein modeling are proposed to accelerate the development of toxicity information on emerging and legacy PFAS, individually and as mixtures. In addition, an appropriate degree of precaution, given what is already known from the PFAS examples noted, may be needed to protect human health. Environ Toxicol Chem 2021;40:606–630. © 2020 SETAC

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are compounds that do not occur in nature but have been widely used since World War II and persist indefinitely in the environment. They are present in the serum of Americans with median levels of 4 ng/mL and 21 ng/mL, respectively. PFOA has been positively associated with cholesterol in several studies of workers. A cross-sectional study of lipids and PFOA and PFOS was conducted among 46,294 community residents aged 18 years or above, who drank water contaminated with PFOA from a chemical plant in West Virginia. The mean levels of serum PFOA and PFOS in 2005–2006 were 80 ng/mL (median, 27 ng/mL) and 22 ng/mL (median, 20 ng/mL), respectively. All lipid outcomes except high density lipoprotein cholesterol showed significant increasing trends by increasing decile of either compound; high density lipoprotein cholesterol showed no association. The predicted increase in cholesterol from lowest to highest decile for either compound was 11–12 mg/dL. The odds ratios for high cholesterol (≥240 mg/dL), by increasing quartile of PFOA, were 1.00, 1.21 (95% confidence interval (CI): 1.12, 1.31), 1.33 (95% CI: 1.23, 1.43), and 1.40 (95% CI: 1.29, 1.51) and were similar for PFOS quartiles. Because these data are cross-sectional, causal inference is limited. Nonetheless, the associations between these compounds and lipids raise concerns, given their common presence in the general population.

Background: The C8 Health Project was created, authorized, and funded as part of the settlement agreement reached in the case of Jack W. Leach, et al. v. E.I. du Pont de Nemours & Company (no. 01-C-608 W.Va., Wood County Circuit Court, filed 10 April 2002). The settlement stemmed from the perfluorooctanoic acid (PFOA, or C8) contamination of drinking water in six water districts in two states near the DuPont Washington Works facility near Parkersburg, West Virginia. Objectives: This study reports on the methods and results from the C8 Health Project, a population study created to gather data that would allow class members to know their own PFOA levels and permit subsequent epidemiologic investigations. Methods: Final study participation was 69,030, enrolled over a 13-month period in 2005–2006. Extensive data were collected, including demographic data, medical diagnoses (both self-report and medical records review), clinical laboratory testing, and determination of serum concentrations of 10 perfluorocarbons (PFCs). Here we describe the processes used to collect, validate, and store these health data. We also describe survey participants and their serum PFC levels. Results: The population geometric mean for serum PFOA was 32.91 ng/mL, 500% higher than previously reported for a representative American population. Serum concentrations for perfluorohexane sulfonate and perfluorononanoic acid were elevated 39% and 73% respectively, whereas perfluorooctanesulfonate was present at levels similar to those in the U.S. population. Conclusions: This largest known population study of community PFC exposure permits new evaluations of associations between PFOA, in particular, and a range of health parameters. These will contribute to understanding of the biology of PFC exposure. The C8 Health Project also represents an unprecedented effort to gather basic data on an exposed population; its achievements and limitations can inform future legal settlements for populations exposed to environmental contaminants.

A peer-reviewed open access journal published by the National Institute of Environmental Health Sciences

Background Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) are man-made compounds with widespread presence in human sera. In previous occupational and adult studies, PFOA and PFOS were positively associated with serum lipid levels. Objective To interrogate associations between PFOA and PFOS and serum lipids in children and adolescents. Design Cross-sectional community-based study. Setting Mid–Ohio River Valley. Participants A total of 12 476 children and adolescents included in the C8 Health Project, which resulted from the pretrial settlement of a class action lawsuit pursuant to PFOA contamination of the drinking water supply. Main Outcome Measures Serum lipids (total, high-density lipoprotein [HDL-C], and low-density lipoprotein [LDL-C] cholesterol and fasting triglycerides). Results Mean (SD) serum PFOA and PFOS concentrations were 69.2 (111.9) ng/mL and 22.7 (12.6) ng/mL, respectively. In linear regression after adjustment for covariables, PFOA was significantly associated with increased total cholesterol and LDL-C, and PFOS was significantly associated with increased total cholesterol, HDL-C, and LDL-C. Using general linear model analysis of covariance, between the first and fifth quintiles of PFOA there was a 4.6-mg/dL and a 3.8-mg/dL increase in the adjusted mean levels of total cholesterol and LDL-C levels, respectively, and an 8.5-mg/dL and a 5.8-mg/dL increase in the adjusted mean levels of total cholesterol and LDL-C, respectively, between the first and fifth quintiles of PFOS. Increases were 10 mg/dL for some age- and sex-group strata. Observed effects were nonlinear, with larger increases in total cholesterol and LDL-C levels occurring at the lowest range, particularly of PFOA. Conclusion Although the epidemiologic and cross-sectional natures of this study limit causal inferences, the consistently observed associations between increasing PFOA and PFOS and elevated total cholesterol and LDL-C levels warrant further study.