Investigating the role of colloids on the distribution of bisphenol analogues in surface water from an ecological demonstration area, China.

Owing to the widespread use of bisphenol analogues (BPs) as substitutes for bisphenol A (BPA), the presence of BPs in multiple environments is of increasing concern. However, there is a limited understanding of the effects of colloids on the distribution and risk assessment of BPs traditionally dissolved in surface water. In this study, seven BPs were investigated in both the truly dissolved (<5 kDa) and colloidal (5 kDa to 1 μm) phases with water, with mean concentrations in the range of 71.6-671 ng/L and 5.84-76.6 ng/L, respectively. BPA and bisphenol S (BPS) were the dominant BPs in both phases, but a clear positive correlation was found between the adsorption contribution proportions of colloids to BPs and their hydrophobicity (octanol-water partition coefficient). The colloids contributed 50.4% of bisphenol AF, 33.4% of tetrabromobisphenol A, 25.2% of bisphenol F, 10.9% of BPA and 9.50% of BPS in the traditionally dissolved phase (<1 μm), which suggests that colloids play an important role in regulating the transformation and transportation of BPs in aquatic environments. Based on BP concentrations in the truly dissolved phase, only moderate risk levels for BPs towards algae, daphnia and fish were posed, and no oestrogenic risk existed in the study area.