Partitioning Behavior of Bisphenol Alternatives BPS and BPAF Compared to BPA

With the pressure to ban or limit the use of bisphenol A (BPA), production of alternatives such as bisphenol AF (BPAF) and bisphenol S (BPS) are increasing, but little is known on their partitioning behavior for use in assessing distribution in the ecosystem. Octanol–water ( D ow pH ) and soil-water partitioning were measured at several pH values for BPA, BPAF, and BPS. Sorption isotherms were constructed from measured aqueous and soil phase concentrations and were fit sufficiently well with a linear sorption model. pH-dependent distribution was observed in both octanol–water and soil-water systems particularly for BPS and BPAF, which have lower estimated p K a values than those for BPA. Accounting for soil organic carbon (OC) content and pH was sufficient to describe sorption reasonable well across the four soils (%OC 0.1–2.5, pH 3.8–8.6); no other soil properties correlated well with bisphenol sorption. However, for a given soil especially for the two high clay low OC soils, BPS sorbed much more than expected relative to observed trends in D ow pH and magnitude appeared correlated to % kaolinite; therefore, Ca 2+ -bridging of BPS to clay edge sites was assessed by comparing sorption from 0.01 N KCl and 0.01 N CaCl 2; however, no significant differences were observed.