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Biotransformation and bioconcentration of 6:2 and 8:2 polyfluoroalkyl phosphate diesters in common carp (Cyprinus carpio): Underestimated ecological risks

Chen, Meng, Guo, Tingting, He, Keyan, Zhu, Lingyan, Jin, Hangbiao, Wang, Qiang, Liu, Menglin, Yang, Liping
The Science of the total environment 2019 v.656 pp. 201-208
Cyprinus carpio, acid phosphatase, bile, bioaccumulation, biotransformation, carboxylic acids, carp, esters, glutathione transferase, liver, metabolism, metabolites, molecular weight, perfluorocarbons, phosphates, risk
Polyfluoroalkyl phosphates esters (PAPs) are widely used in a variety of commercial products, and have been detected in many aquatic organisms. In this study, common carps (Cyprinus carpio) were administered with 6:2 and 8:2 diPAP in water to investigate their bio-accumulation and transformation in fish. Several degradation products, including fluorotelomer unsaturated carboxylic acids (6:2 and 8:2 FTUCA), 5:3 and 7:3 fluorotelomer carboxylic acids (5:3 and 7:3 FTCA), perfluoroalkyl carboxylates (PFCAs) were identified in the carp liver. In addition, several phase-II metabolites, such as glutathione- and glucuronide-conjugated compounds were detected in the carp bile. 8:2 diPAP displayed lower accumulation potential than 6:2 diPAP probably due to its relatively large molecular size. However, 8:2 diPAP experienced more extensive transformation (transformation rate 6.78–14.6 mol%) and produced more phase I metabolites than 6:2 diPAP (0.49–0.66 mol%). The in vitro incubation with the liver S9 fraction confirmed that biotransformation of 6:2 and 8:2 diPAP took place in the carp liver. Further analyses of enzyme activities indicated that acid phosphatase (ACP) could be involved in mediating phase I while glutathione S-transferase (GST) involved in phase II metabolism of 6:2 and 8:2 diPAP in carp.