长江口东滩湿地柱状沉积物中多氯联苯的分布和变化趋势

采用同位素稀释质谱法，用高分辨率气相色谱-高分辨率质谱仪(HRGC-HRMS)对长江口崇明东滩湿地柱状沉积物30个层段中7种指示性多氯联苯(PCB28，PCB52，PCB101，PCB118，PCB153，PCB138和PCB180)的含量进行了测定. 结合近几十年长江下游气候变化情况，对PCBs垂直分布历史记录特征以及异构体的物理化学性质参数进行了探讨. 结果表明，w(PCBs)为0.138～0.400 ng/g(以干质量计，下同)，平均值为0.228 ng/g，属于轻度污染. 东滩沉积物中PCBs呈现明显的周期性分布，在20世纪50年代初期开始快速增长，高峰期出现在70年代，之后呈减少趋势，反映了世界主要生产国家禁止生产PCBs的情况. 

Distribution and Vertical Trends of PCBs in a Sediment Core from Dongtan Wetland, Yangtze River Estuary

Concentrations of seven indicator polychlorinated biphenyls (PCB28，PCB52，PCB101，PCB118，PCB153，PCB138 and PCB180) in 30 layers of a sediment core collected from Dongtan Wetland in the Yangtze River estuary of the East China Sea were measured using isotope dilution mass spectrometry (IDMS) with HRGC-HRMS. Combined with the climate variations in the lower reaches of the Yangtze River basin over the past ten years, the vertical distribution record of PCBs and physico-chemical parameters of the isomers were also preliminarily discussed. The results showed that the total concentrations of the seven indicator PCB isomers in each of the layers of the core were in the range of 0.138-0.400 ng/g (dry weight), with an average of 0.228 ng/g, showing a low pollution level. The distributional characteristics of PCBs with depth showed periodic variations. The vertical trend of PCBs in the core showed rapid growth in the early 1950s, began to peak in the 1970s, then tended to decrease, reflecting the national prohibition of PCBs production.