Halogenated organic compounds in mangrove sediments from Bintan Island, Indonesia: Occurrence, profiles, sources, and potential ecological risk

The first comprehensive analysis of halogenated organic compounds (HOCs), including 209 full congeners of polychlorinated biphenyls (PCBs), 26 organochlorinated pesticides (OCPs), 41 polybrominated diphenyl ethers (PBDEs), and four other brominated flame retardants (BFRs), was performed on surface mangrove sediments from Bintan Island, Province of the Riau Archipelago, Indonesia. Among the measured HOC contaminants, the mean concentration of ∑209PCBs (2.3 ± 0.96 ng g−1 dw) was higher than that of p,p’-DDE (1.8 ± 0.70 ng g−1 dw), ∑41PBDEs (1.8 ± 1.1 ng g−1 dw), trans-nonachlor (0.42 ± 0.13 ng g−1 dw), and other BFRs (0.20 ± 0.29 ng g−1 dw), while other OCP related compounds less than 0.2 ng g−1 dw. In addition, concentrations of unintentionally produced PCBs such as PCB-11 and PCB-47/48/75 ranged from 0.57 to 1.5 ng g−1 dw. Variations in HOCs accumulation and profiles among mangrove habitats and species indicate different anthropogenic stressors and species-specific accumulations. The ecological risk estimation from HOCs exposure on dwelling sediment biota in mangrove sediments varied from no risk to potentially causing adverse effects in several locations. Overall, this study provides fundamental information on the function of mangrove ecosystems as an accumulation zone for HOCs in tropical regions.