松花江流域河流沉积物中多氯联苯的分布、来源及风险评价

为查明松花江流域沉积物中多氯联苯(PCBs)分布、来源及污染现状,利用GC-ECD和GC-MS测定松花江流域沉积物中PCBs含量,并运用美国国家环保署法(EPA)、加拿大沉积物环境质量标准(SQG)和潜在生态危害指数法(Er)对沉积物中PCBs生态风险进行评价.结果表明,河流沉积物中均有2～10氯代的PCBs同系物被检出;松花江流域沉积物中PCBs含量介于0.83～125.53 ng.g-1,其中嫩江为0.83～4.44 ng.g-1,第二松花江为12.44～125.53 ng.g-1,松花江干流为1.74～6.25ng.g-1;沉积物中PCBs含量最高的是第二松花江,主要来源于沿江分布的与油漆、绝缘材料等工业品有关的污染源,其它河流沉积物中以二氯联苯为主的PCBs主要来源于大气沉降.3种方法(EPA、SQG、Er)的风险评价显示第二松花江沉积物中的PCBs已达到中等到较强程度的污染,其它河流沉积物中的PCBs暂无生态风险.

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 (E_r) 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·g^-1 to 125.53 ng·g^-1in sediments of Songhua river basin, 0.83-4.44 ng·g^-1 for Nen River, 12.44-125.53 ng·g^-1 for Second Songhua River, and 1.74-6.25 ng·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 E_r) 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.