[Distribution, sources and ecological risk assessment of polychlorinated biphenyl in sediments from Songhua River Basin].

In order to find out the distribution, source and pollution situation of Polychlorinated Biphenyls (PCBs) in sediments of Songhua River basin, GC-ECD and GC-MS were used to determine the PCBs contents in sediments of Songhua River basin. Regulations of the United States Environmental Protection Agency (EPA), the Canadian Sediment Quality Guidelines (SQG) and the potential ecological risk index (Er) were utilized to evaluate the ecological risk of PCBs in the sediments. The results showed that 2-10 PCBs congeners were detected in the sediments. The total contents of PCBs varied from 0.83 ng x g(-1) to 125.53 ng x g(-1) in sediments of Songhua river basin, 0.83-4.44 ng x g(-1) for Nen River, 12.44-125.53 ng x g(-1) for Second Songhua River, and 1.74-6.25 ng x g(-1) for the mainstream of Songhua River. The highest level of PCBs was detected in sediments of Second Songhua River, which mainly came from pollution sources which are related with industrial products such as paint, insulation materials and the like, and were distributed along the river. While in other rivers, the dominant PCB was Dichlorobiphenyl, which mainly came from the atmospheric deposition. Risk assessment using three methods (EPA, SQG and Er) showed that PCBs in the sediment of the Second Songhua River has already reached the medium to high level of contamination, and PCBs in sediments of other rivers has no ecological risks at the moment.