Perfluorooctane Sulfonate (PFOS) and Related Perfluorinated Compounds in Human Maternal and Cord Blood Samples: Assessment of PFOS Exposure in a Susceptible Population during Pregnancy

Abstract

Fluorinated organic compounds (FOCs), such as perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and perfluorooctane sulfonylamide (PFOSA), are widely used in the manufacture of plastic, electronics, textile, and construction material in the apparel, leather, and upholstery industries. FOCs have been detected in human blood samples. Studies have indicated that FOCs may be detrimental to rodent development possibly by affecting thyroid hormone levels. In the present study, we determined the concentrations of FOCs in maternal and cord blood samples. Pregnant women 17–37 years of age were enrolled as subjects. FOCs in 15 pairs of maternal and cord blood samples were analyzed by liquid chromatography–electrospray mass spectrometry coupled with online extraction. The limits of quantification of PFOS, PFOA, and PFOSA in human plasma or serum were 0.5, 0.5, and 1.0 ng/mL, respectively. The method enables the precise determination of FOCs and can be applied to the detection of FOCs in human blood samples for monitoring human exposure. PFOS concentrations in maternal samples ranged from 4.9 to 17.6 ng/mL, whereas those in fetal samples ranged from 1.6 to 5.3 ng/mL. In contrast, PFOSA was not detected in fetal or maternal samples, whereas PFOA was detected only in maternal samples (range, < 0.5 to 2.3 ng/mL, 4 of 15). Our results revealed a high correlation between PFOS concentrations in maternal and cord blood (r2 = 0.876). However, we did not find any significant correlations between PFOS concentration in maternal and cord blood samples and age bracket, birth weight, or levels of thyroid-stimulating hormone or free thyroxine. Our study revealed that human fetuses in Japan may be exposed to relatively high levels of FOCs. Further investigation is required to determine the postnatal effects of fetal exposure to FOCs.

Determinants of maternal and fetal exposure and temporal trends of perfluorinated compounds

“…PFOS and PFOA levels were roughly the same across the maternal age groups, which is in accordance with the previous studies by Inoue et al (2004) and Apelberg et al (2007a In two previous studies, no associations between maternal BMI and maternal or cord serum PFC levels were found which are consistent with our results (Inoue et al 2004;Rylander et al 2009). Three other studies showed inverse associations between PFOS and PFOA levels and BMI in women or men (Fei et al 2007;Eriksen et al 2011;Lindh et al 2012).…”

“…PFCs cross the placenta, but umbilical cord concentrations have in most studies been lower than those observed in maternal serum or plasma (Inoue et al 2004;Fromme et al 2010;Jensen et al 2012;Gützkow et al 2012). In the present study, we found higher levels of PFCs in maternal serum than in cord serum, which is consistent with previous studies (Monroy et al 2008;Hanssen et al 2010;Beesoon et al 2011).…”

“…PFCs have been shown to cross the placenta (Inoue et al 2004;Liu et al 2011;Gützkow et al 2012) and thus have a potential to exert a direct influence on the developing fetus (Apelberg et al 2007a;Fei et al 2007). According to previous studies, the median PFC concentrations in cord blood ranged from 30 to 130% of the maternal concentrations (Liu et al, 2011, Kim et al 2011a, Gützkow et al 2012).…”

“…2007;Apelberg et al 2007b;Washino et al 2009). The findings on the effect of infant sex (Inoue et al 2004;Apelberg et al 2007b) and gestational age (Apelberg et al 2007a, b;Nolan et al 2009) on the levels of PFCs are limited. Many of those studies on the determinants have contradicting results.…”

“…Consequently, higher levels of PFOA were measured in cord blood from male fetuses. Previous research on sex effect on PFC exposure is contradicting and has no reasonable explanation (Inoue et al 2004;Apelberg et al 2007a;Zhang et al 2011). We believe that our finding is a chance finding and could be due to multiple testing.…”