First Report on In Vivo Pharmacokinetics and Biotransformation of Chlorinated Polyfluoroalkyl Ether Sulfonates in Rainbow Trout

This study provides the first in vivo pharmacokinetic
data for
chlorinated perfluorooctanesulfonate (Cl-PFOS), 6:2 and 8:2 chlorinated
polyfluoroalkyl ether sulfonates (Cl-PFESAs), upon a 30 day dietary
exposure and 34 day depuration phase in rainbow trout (Oncorhynchus
mykiss). Biological handling of these three novel molecules
and legacy PFOS were investigated via cross-comparison. PFOS and Cl-PFOS
displayed comparable bioaccumulative potencies and similar distribution
tendencies in tissues (blood > liver > kidneys), despite the
presence
of a terminal chlorine atom in Cl-PFOS molecule. The Cl-PFESAs, especially
8:2 Cl-PFESA, were predominantly assimilated from the bloodstream
by liver and kidneys and resisted elimination, leading to higher bioaccumulation
factors in liver than in blood (0.576 and 0.254, respectively, for
8:2 Cl-PFESA) and longer half-lives in liver and kidneys than PFOS,
suggesting these alternatives may pose greater risks in terms of the
great accumulation potentials in fish tissues. The present study provides
the first report of the in vivo transformation of 6:2 and 8:2 Cl-PFESAs
and identifies 6:2 and 8:2 H-PFESAs as their respective sole metabolites.
This provides the first line of evidence suggesting that the transformation
susceptibility of Cl-PFESAs in organisms is distinct from their environmental
persistence.