Bioavailability and bioconcentration potential of perfluoroalkyl-phosphinic and -phosphonic acids in zebrafish (Danio rerio): Comparison to perfluorocarboxylates and perfluorosulfonates

Currently information regarding bioavailability and bioconcentration potential of perfluoroalkyl phosphinic acids (PFPiAS) in quatic organisms does not exist. The main objective of the present study was to assess uptake and elimination kinetics of PFPiAS in zebrafish (Danio rerio) following aqueous exposure. The results showed that PFPiA exposure can result in very high steady-state bioconcentration factors (BCFss), compared to perfluorocarboxylates and perfluorosulfonates C6/C10 PFPiA exhibited the highest BCFss, ranging between 10(7) and 10(10), orders of magnitude higher than those for long-chain perfluorocarboxyltes. Strong positive relationships were observed between BCFss versus the membrane-water distribution coefficient (D-mw) and the protein-water partition coefficient (K-pw) of the studied perfluoroalkyl substances. However, BCFss exhibited a substantial drop for the very hydrophobic PFPiAS (C8/C10 and C6/C12 PFPiAS). The phase and/or reduced gill membrane permebaility. While PFPiAs can be metabolized to perfluoroalkyl phosphonic acids, the metabolic transformation rate seems insuffieient to counteract the high degree of uptake across gill membranes. These findings help to better understand exposure pathways and bioaccumulation behavior of these important perfluorinated acids in aquatic systems. (C) 2016 Elsevier B.V. All rights reserved.