Per- and polyfluoroalkyl substances in human serum and urine samples from a residentially exposed community

Abstract

Background: Per- and polyfluoroalkyl substances (PFAS) are considered chemicals of emerging concern, in part due to their environmental and biological persistence and the potential for widespread human exposure. In 2007, a PFAS manufacturer near Decatur, Alabama notified the United States Environmental Protection Agency (EPA) it had discharged PFAS into a wastewater treatment plant, resulting in environmental contamination and potential exposures to the local community.

Objectives: To characterize PFAS exposure over time, the Agency for Toxic Substances and Disease Registry (ATSDR) collected blood and urine samples from local residents.

Methods: Eight PFAS were measured in serum in 2010 (n=153). Eleven PFAS were measured in serum, and five PFAS were measured in urine (n=45) from some of the same residents in 2016. Serum concentrations were compared to nationally representative data and change in serum concentration over time was evaluated. Biological half-lives were estimated for perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and perfluorohexane sulfonic acid (PFHxS) using a one-compartment pharmacokinetic model.

Results: In 2010 and 2016, geometric mean PFOA and PFOS serum concentrations were elevated in participants compared to the general U.S.

Population: In 2016, the geometric mean PFHxS serum concentration was elevated compared to the general U.S.

Population: Geometric mean serum concentrations of PFOA, PFOS, and perfluorononanoic acid (PFNA) were significantly (p≤0.0001) lower (49%, 53%, and 58%, respectively) in 2016 compared to 2010. Half-lives for PFOA, PFOS, and PFHxS were estimated to be 3.9, 3.3, and 15.5years, respectively. Concentrations of PFOA in serum and urine were highly correlated (r=0.75) in males.

Conclusions: Serum concentrations of some PFAS are decreasing in this residentially exposed community, but remain elevated compared to the U.S. general population.

Keywords: Biomonitoring; Half-life; PFAS; PFOA; PFOS.

Fig. 1

Comparison of Mean PFAS Serum Concentrations in a National Reference Population and Occupational and Community Biomonitoring Studies. Mean PFOA (a) and PFOS (b) serum concentrations measured in the 2010 and 2016 investigations compared to national reference populations, and occupational and community biomonitoring studies. References: 3M Workers (Olsen et al., 2003); Dupont (Sakr et al., 2007); Little Hocking, OH (Emmett et al., 2006); Ohio River Valley (Steenland et al., 2009); Minnesota Pilot Study – Minnesota Department of Health 2009; Red Cross Blood Donors (Olsen et al., 2008); NHANES (CDC, 2017).

Fig. 2

PFOA (A), PFOS (B), and PFHxS (C) serum concentrations measured in 2010 in the vicinity of Decatur, AL, stratified by drinking water source. White bars show serum concentrations measured in participants with drinking water from a private well with detectable levels of PFAS (maximum PFOA concentration = 2.2 μg/L, maximum PFOS concentration =0.365 μg/L). Grey bars show serum concentrations measured in participants with drinking water without detectable PFAS concentrations. Lined bars show serum concentrations measured in participants with drinking water provided by the West Morgan East Lawrence Municipal Water Authority. Box plots indicate the minimum, maximum, and interquartile range.