Conjugated metabolites of bisphenol A and bisphenol S in indoor dust, outdoor dust, and human urine.

Bisphenol A (BPA) and bisphenol S (BPS) have been widely spread in the global environment. However, for conjugated BPA and BPS metabolites, limited studies have investigated their occurrence in environmental matrices. We collected paired indoor and outdoor dust (n = 97), as well as human urine (n = 153) samples, from residential houses in Quzhou, China, and measured these samples for 8 conjugated BPA and BPS metabolites. Three BPA metabolites were found in collected indoor and outdoor dust, with BPA sulfate (mean 0.75 and 1.3 ng/g, respectively) and BPA glucuronide (0.13 and 0.26 ng/g) being more abundant. BPA conjugates accounted for a mean of 42 and 56% of total BPA (sum of conjugated BPA and BPA metabolites) in indoor and outdoor dust, respectively. BPS sulfate (mean 0.29 and 0.82 ng/g, respectively) had consistently higher concentrations than BPS glucuronide (0.13 and 0.27 ng/g) in indoor and outdoor samples. BPS conjugates contributed a mean 32% and 45% of total BPS (sum of BPS and BPS metabolites) in indoor and outdoor dust, respectively. Moreover, conjugated BPA and BPS metabolites in indoor or outdoor dust were not significantly correlated with those in urine from residents. Overall, this study first demonstrates the wide presence of conjugated BPA and BPS metabolites, besides BPA and BPS, in indoor and outdoor dust. These data are important for elucidating the sources of conjugated BPA and BPS metabolites in the human body.