Monitoring and assessment of persistent organochlorine residues in sediments from the Daliaohe River watershed, northeast of China.

Surface sediment samples from 12 sites of the three selected rivers in Daliaohe River watershed (Hunhe River, Taizihe River and Daliaohe River) were analyzed with the objective of establishing sources and hazard of the organochlorinae pesticides (OCPs) and polychlorinated biphenyl (PCBs) in surface sediments. The total concentrations of OCPs varied from 3.06 to 23.24 ng g(-1). SigmaHCH (alpha-HCH, beta-HCH, delta-HCH, gamma-HCH), SigmaDDT (p, p'-DDE, p, p'-DDD, o, p'-DDT, p, p'-DDT) and SigmaCyclodiene (Heptachlor, Aldrin, Heptachlor epoxide, Dieldrin, Endrin) ranged from 1.86 to 21.48, 0.5 to 2.81 and 0.56 to 1.53 ng g(-1), respectively. Results of OCPs also illustrate that the most dominant pollutants among the OCPs was SigmaHCH, and gamma-HCH was the most dominant isomer in HCH, which was evidence of recent input of lindane. It possibly came from the runoff of polluted soils and long-scale transportation. Total PCB concentrations ranged between 1.88 and 16.88 ng g(-1). The peak concentrations of PCBs were found in sediments from station T5 and D3, which are in the vicinity of industrial areas and ferry, respectively. These data show a moderate level of OCPs and PCBs contaminations compared to that in other countries.