PFOS and PFOA in paired urine and blood from general adults and pregnant women: assessment of urinary elimination

Abstract

Although levels of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in human blood are well documented, information on elimination of these chemicals is limited. In this study, PFOS and PFOA were analyzed in 81 whole blood-urine paired samples from general adults and pregnant women in Tianjin, China. PFOS and PFOA were detected in 48 and 76% of adult urine (AU) samples, with geometric mean (GM) concentrations of 0.011 and 0.008 ng/mL, respectively; whereas relatively low PFOS and PFOA concentrations were found in maternal urine (MU) samples, with GM concentrations of 0.006 and 0.003 ng/mL, respectively. For PFOA, the coefficients of Pearson's correlation between whole blood concentrations and creatinine-adjusted and creatinine-unadjusted urinary concentrations were 0.348 (p = 0.013) and 0.417 (p = 0.002), respectively. The GM urinary elimination rates of PFOS (PFOSUER) and PFOA (PFOAUER) were 16 and 25%, respectively, for adults. These results indicate that urine is an important pathway of excretion of perfluoroalkyl substances (PFASs). The partitioning ratios of PFAS concentration between urine and whole blood (PFASU/B) in pregnant women (PFOSU/B, 0.0004; PFOAU/B, 0.0011) were significantly lower (p = 0.025 for PFOSU/B, p = 0.017 for PFOAU/B) than the ratios found in non-pregnant women (PFOSU/B, 0.0013; PFOAU/B, 0.0028). Furthermore, our results suggest a clear gender difference in the urinary elimination of PFOA, with male adults (31%) having significantly higher PFOAUER than that of female adults (19%). PFOSUER was significantly inversely correlated with age (r = -0.334, p = 0.015); these findings suggest that urinary elimination of PFOS is faster in young adults than in the elderly.

Association of perfluorinated chemical exposure in utero with maternal and infant thyroid hormone levels in the Sapporo cohort of Hokkaido Study on the Environment and Children’s Health

“…That suggests no doseresponse relationships among male infants. Although the reason for sex differences is not understood, one explanation for the sex difference is the faster elimination time of PFCs in female compared to male in animal studies [32,33]. We found that the PFOA level had no effect on TSH or FT4, implying that PFOS is more influential than PFOA on human THs.…”

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

“…Notably, the correlation between PFOA serum and urine in male participants is much stronger than other non-sex-specific estimates reported elsewhere in the literature (Zhang et al, 2013). Other studies of the correlation between PFOA serum and urine concentrations in paired samples have reported stronger correlations in non-pregnant adults compared to pregnant women (Zhang et al, 2015). These findings support our conclusion that non-renal excretion pathways play an important role in PFOA clearance in women.…”

“…Prior efforts to characterize half-lives for these compounds have relied heavily on estimated intake rates, and in some cases, single time-point serum measurements (Zhang et al, 2015). Additionally, estimates that fail to account for ongoing exposure have the potential to overestimate biological half-life.…”

Perfluorinated chemicals in blood serum of inhabitants in central Poland in relation to gender and age

“…Constantly updated biomonitoring results are an important element used in both risk assessments together with toxicological data as points of departure (PoD) when determining the hazard quotient profiles (HQ) or for statistical models based on population data (age, gender) and biomarker levels of selected chemicals that can allow determination of the total concentration of certain environmental pollutants in the human body (Jain, 2015). This is particularly important in the case of PFASs, which have been shown diverse geographical distribution, as well as tissue distribution and different rates of excretion of individual PFASs in humans depending on their age and sex (Cho et al, 2015;Harada et al, 2004;Zhang et al, 2015).…”