Dynamics of PCDDs/DFs and coplanar-PCBs in an aquatic food chain of Tokyo Bay

Concentrations and accumulation profiles of PCDDs/DFs and coplanar-PCBs (co-PCBs) in aquatic biota (e.g., plankton, shellfish, benthic invertebrate, and fish) and sediment from Tokyo Bay were examined to elucidate the relationship between bioaccumulation and trophic level in the food web as determined by the stable nitrogen isotope analysis. Bioaccumulation patterns of PCDDs/DFs and co-PCBs varied greatly among congeners. Accumulation patterns of PCDDs/DFs and co-PCBs are not solely explained by their physicochemical properties. Biota-sediment accumulation factors (BSAFs) for co-PCBs in biota from Tokyo Bay were significantly greater than those of PCDDs/DFs. Furthermore, the slopes of the plots of delta15N and BSAF values and water solubility of 2,3,7,8-substituted PCDDs/DFs and co-PCBs were highly correlated. The results of our study would provide the valuable information to understand the accumulation properties of PCDDs/DFs and co-PCBs that can be used as a scientific basis to determine the sediment quality criteria of PCDDs/DFs and co-PCBs.