PBDE and PCB accumulation in benthos near marine wastewater outfalls: The role of sediment organic carbon

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in sediments and benthic invertebrates near submarine municipal outfalls in Victoria and Vancouver, B.C., Canada, two areas with contrasting receiving environments. PBDE concentrations in wastewater exceeded those of the legacy PCBs by eight times at Vancouver and 35 times at Victoria. Total PBDE concentrations in benthic invertebrates were higher near Vancouver than Victoria, despite lower concentrations in sediments, and correlated with organic carbon-normalized concentrations in sediment. Principal Components Analysis indicated uptake of individual PBDE congeners was determined by sediment properties (organic carbon, grain size), while PCB congener uptake was governed by physico-chemical properties (octanol-water partitioning coefficient). Results suggest the utility of sediment quality guidelines for PBDEs and likely PCBs benefit if based on organic carbon-normalized concentrations. Also, where enhanced wastewater treatment increases the PBDEs to particulate organic carbon ratio in effluent, nearfield benthic invertebrates may face increased PBDE accumulation.

► Physical receiving environment affects PBDE bioaccumulation by benthic invertebrates.
► PBDE uptake is correlated with organic-carbon normalized sediment concentrations.
► PBDE and PCB congener uptake are governed by different properties.
► PBDE sediment quality guidelines may benefit by using organic carbon-normalized data.
► Enhanced wastewater treatment may mean increased benthic invertebrate PBDE bioaccumulation.