Application of compound-specific stable carbon isotope analysis for the biotransformation and trophic dynamics of PBDEs in a feeding study with fish

The debromination and trophic dynamics of PBDEs in fish and whether or not compound-specific isotopic analysis (CSIA) can be used to trace these processes were investigated. Two predator/prey relationships were established in laboratory by two predatory fish species, oscar fish (OF) and redtail catfish (RF) feeding on tiger barb (TB) exposed to a commercial PBDE mixture. Metabolic debromination of PBDEs was observed in the TB and the OF, but not in the RF. The calculated biomagnification factors (BMFs) were uniform for most of the congeners in RF/TB but varied in OF/TB, which can be attributed to the metabolic debromination in the OF. The δ13C values of BDE47 and BDE28 were lower in fish than in those in the commercial mixture but the δ13C values of BDE99 were slightly higher. These results indicated that CSIA can be used to trace the biotransformation of PBDEs in biota.

► The δ13C values of individual BDE congeners in fish were accurately determined.
► Species-specific debromination was found among three fish species.
► The calculated BMFs was found to be controlled by the species-specific debromination.
► The changes in δ13C of BDE congeners can reflect the debromination occurred in the fish.
► CSIA is a powerful tool for monitoring biotransformation of PBDEs.