Sources and distribution of hexabromocyclododecanes (HBCDs) in Japanese river sediment

The distribution of hexabromocyclododecane (HBCD) in the sediment of three Japanese rivers with different characteristics (i.e., population and potential source in the catchment) was investigated and compared with the results estimated using a multimedia fate model (ChemCAN). High concentrations of HBCD in sediments in the range of 134-2060 ng g(-1) were found in a river receiving textile wastewater. This contrasted with the much lower concentrations (0.8-4.8 ng g(-1)) observed for an urban river (with a surrounding population of 1.8 million). The medians of observed HBCD concentrations in each river were close to those estimated based on the assumed input source (e.g., 1810 ng g(-1) for the observed median concentration, and 1436 ng g(-1) for the estimation, in the Kuzuryu River). These results demonstrated the importance of considering source contributions of HBCD, including both industrial and consumer sources, to aquatic environments, for reliable risk management.