太湖表层沉积物中PAHs和PCBs的分布及风险评价

Polycyclic aromatic hydrocarbons and polychlorinated biphenyl in surface sediments of Taihu Lake:the distribution,sources and risk assessment

采用GC-EI-MS联用技术分析了太湖18个表层沉积物样品中多环芳烃(PAHs)和多氯联苯(PCBs)的含量.共检出28种PAHs,其总浓度范围为90.6～1.04×103ng/g,其中16种优控PAHs的浓度范围为63.1～885ng/g,最高浓度出现在竺山湖;56种PCBs的浓度范围为1.35～13.8ng/g,最高浓度出现在新塘港.利用分子比和因子分析/多元线性回归模型分析PAHs的来源,结果显示,太湖PAHs主要来源于燃烧,其中木柴、煤炭燃烧和油料燃烧的贡献率分别为45%和50%.PCBs同族体组成分析结果表明,PCBs的同系物组成呈现Aroclor1242和Aroclor1254的混合来源特征.太湖表层沉积物中PAHs和PCBs的二噁毒性当量(以TCDD计)范围为0.64～3.35pg/g,风险评价结果表明,太湖沉积物中的PAHs和PCBs尚未对周围环境造成不利影响.

Eighteen surface sediment samples were collected from Taihu Lake and analysed for polycyclic aromatic hydrocarbons （PAHs） and polychlorinated biphenyl （PCBs） with GC-EI-MS. The concentrations of 28 PAH compounds detected ranged from 90.6 to 1.04×10^3 ng/g, with the highest concentration observed in sediments of Zhushanhu Lake. Concentrations of 16 PAHs identified as priority pollutants was in the range of 63.1-885ng/g. The PCBs concentrations ranged from 1.35 to 13.8 ng/g, and the highest concentration was found in Xintanggang area. The PAlls in the study area were mainly originated from pyrogenic source as indicated by the ratios of PAH homologues, factor analysis and multiple line regression. Furthermore, the combustion of coal or wood and the combustion of oil accounted for 45% and 50% of the total PAlls in the surface sediments, respectively. The PCB homologue profiles indicated that the source of PCBs in sediments was a mixture of Aroclor 1242 and Aroclor 1254. The total dioxin equivalents of PAHs and PCBs in the sediments from Taihu Lake ranged from 0.64 to 3.35 pg/g. The risk evaluation suggestsed that the PAHs and PCBs in the sediments of the study area might pose little harm to the environment.