Isomer-Specific Bioaccumulation and Trophic Transfer of Dechlorane Plus in the Freshwater Food Web from a Highly Contaminated Site, South China

Abstract

Dechlorane Plus (DP), a highly chlorinated flame retardant, has been detected in water, sediment, and aquatic organisms in a reservoir in the vicinity of electronic waste recycling workshops in South China. The biomagnification potential of DP in the food web was assessed and compared with that of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). DP was detected in all of the aquatic species, with concentrations of 19.1-9630 ng/g lipid wt. A depletion of anti-DP was observed in organisms compared with abiotic samples and the fraction of anti-DP was found to be further decreased upon moving up the trophic levels. This result suggested a stereospecific metabolism of anti-DP and/or isomer-selective uptake of syn-DP was occurring in organisms. Both syn- and anti-DP were significantly biomagnified in the present food web, with trophic magnification factors (TMFs) of 11.3 and 6.6, respectively. The trophic magnification potentials of the DP isomers were generally comparable to or lower than those of the highly recalcitrant PCB congeners in the same food web, but were 2-3 times greater than those of PBDE congeners.