Do Human Exposures to Bisphenol A and Three other Bisphenol Analogs Track Market Changes?

摘要

Human exposure to bisphenol A (BPA) is widespread because of the extensive use of this chemical in consumer products. Due to the toxicity of BPA in animal studies and its potential effects on human health, several government entities in different countries have banned its use in certain products. In response to these restrictions and public pressure, the use of BPA may decrease, while the use of some of its analogs, such as bisphenol S (BPS, 4,4-sulfonyldiphenol), bisphenol F (BPF, 4,4'-dihydroxydiphenylmethane), and bisphenol AF (BPAF, hexafluorobisphenol A), may increase. Limited data suggest that BPS, BPF, and BPAF, similar to BPA, possess slight to moderate acute toxicity and weak estrogenicity. Although the potential environmental and health impacts of BPA analogs are largely unknown, understanding the extent of human exposure to these chemicals is necessary for risk assessment. We measured both total (free plus conjugated) and free urinary concentrations of BPA, BPF, BPS, and BPAF in samples collected between 2009 and 2012 from 100 adult volunteers, using on-line solid-phase extraction-isotope dilution-high-performance liquid chromatography-tandem mass spectrometry. The conjugate species represented more than 95% of the excreted bisphenols. We detected BPA at the highest frequency and median concentrations (95%, 0.72 ng/mL), followed by BPS (78 %, 0.13 ng/mL), BPF (55 %, 0.08 ng/mL), and BPAF (10 %, ＜limit of detection). The median concentration of BPA, similar to those reported among the general US population in 2011-2012, is lower than concentrations reported in 2003-2004. Together, these data suggest that exposure to BPA analogs may have increased since 2009 while the exposure to BPA is showing a clear downward trend. These changes in human exposure to bisphenols may reflect shifts in commercial formulations, public awareness, and regulations.