Bioaccumulation and Biomagnification of Polychlorinated Biphenyls and Dichlorodiphenyltrichloroethane in Biota from Qilianyu Island, South China Sea

Six biota species were collected from Qilianyu Island, South China Sea to determine the bioaccumulation and biomagnification of polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane and its metabolites (DDTs). Concentrations of Sigma PCBs and Sigma DDTs in biota from Qilianyu Island ranged from 6.88 to 519.1 ng/g lipid weight (1w) and 7.0 to 19,413 ng/g lw, respectively. Significant differences for PCBs and DDTs concentrations were found among the six biota species from Qilianyu Island. The levels of PCBs and DDTs in intermediate egret were significantly higher than the other five biota species, which can be attributed to their different feeding and living habits. Significantly negative relationships between concentrations of PCBs and DDTs and delta 13C values in the six biota species confirmed that dietary source is an important factor to determine the levels of PCBs and DDTs in biota species. Sigma PCBs, Sigma DDTs, PCB 28/31, PCB 52, and p,p'-DDE were biomagnified in the biota species from Qilianyu Island, and native species are suitable for studying the biomagnification of the contaminants. The toxic equivalent concentrations in birds from Qilianyu Island were significantly and positively correlated with PCBs concentrations, indicating that high concentrations of non- and mono-ortho-PCB congeners may induce adverse effects on bird species.

Automated summary

The study found significant differences in PCBs and DDTs concentrations among the six biota species from Qilianyu Island. The levels of PCBs and DDTs in intermediate egret were significantly higher than the other five biota species, likely due to their different feeding and living habits. The study also confirmed that dietary source is an important factor in determining the levels of PCBs and DDTs in biota species, and biomagnification of contaminants occurred in the native species on the island.