Biotransformation of the 8:2 fluorotelomer acrylate in rainbow trout. 1. In vivo dietary exposure.

The bioaccumulation and biotransformation of the 8:2 fluorotelomer acrylate (C(8) F(17) CH(2) CH(2) OC(O)CH = CH(2) , 8:2 FTAc) was investigated in rainbow trout via dietary exposure. The 8:2 FTAc is a monomer used in the manufacture of fluorinated polymers and has been widely detected in the atmosphere. The parent 8:2 FTAc and suspected intermediate and terminal metabolites were monitored in liver, blood, kidney, bile, and feces during the 5-d uptake and 8-d elimination phases using gas chromatography-mass spectrometry (GC-MS)- and liquid chromatography-tandem mass spectrometry (LC-MS/MS)- based methods. Very low levels of the 8:2 FTAc were detected in the internal tissues and feces, suggesting that the 8:2 FTAc was rapidly biotransformed in the gut or liver. Similarly, low concentrations of the 8:2 fluorotelomer alcohol (FTOH) were accumulated in the fish tissues. The 8:2 saturated fluorotelomer carboxylate (FTCA) was formed in the highest concentration, reaching steady-state tissue concentrations of approximately 1,000 to 1,400 ng/g wet weight. The 8:2 FTUCA and 7:3 FTCA were also accumulated in high levels, at levels approximately 10-fold lower than the 8:2 FTCA. Both the 7:3 FTCA and perfluorooctanoate (PFOA) showed increasing levels throughout the uptake phase and into the initial stages of the elimination phase, indicating continued formation through precursors still present in the body. Perfluorononanoate (PFNA) was formed in low nanogram per gram wet weight levels. The intermediate and terminal metabolites were also detected in the bile and feces, indicating an important elimination pathway for these compounds. In addition, the 8:2 FTOH glucuronide conjugate was measured in relatively high concentrations in the bile and feces. The results of the current study demonstrated a scenario in which a biologically labile compound is biotransformed to terminal metabolites that are much more biologically persistent.