State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing, China.
Chemosphere. 2013 May;91(6):809-16. doi: 10.1016/j.chemosphere.2013.01.085. Epub 2013 Feb 22.
The surface sediment samples taken from 30 sites of the Yangtze Estuary in both the flood and dry seasons were analyzed to reveal the spatial and seasonal distributions of polychlorinated biphenyls (PCBs). Samples collected in the flood season showed higher PCB concentrations, larger PCB fluctuations and higher portions of large grain sediments in the inner estuary area compared with those collected in the dry season, indicating significant seasonal variations of PCBs. The effects of the physicochemical characteristics (TOC and grain size) of surface sediments on the distributions of PCBs were also investigated. Masked by various other factors, the TOC contents and sediment grain sizes did not exhibit a strong influence on the distributions of PCBs. Analysis of the PCB homolog and congener distribution patterns revealed a predominant proportion of light PCBs with 2-3 chlorines. According to the PCB homolog profiles and principal component analysis (PCA) of source contributions, non-point sources including atmospheric deposition and surface runoff associated with stormwater were suggested to be the major sources of PCBs in the surface sediments of the Yangtze Estuary.
本研究采集了长江口丰水期和枯水期共 30 个站位的表层沉积物样品，分析了多氯联苯（PCBs）在长江口的空间分布和季节变化特征。结果表明，与枯水期相比，丰水期表层沉积物中 PCBs 浓度更高，波动更大，大颗粒沉积物比例更高，表明 PCBs 存在明显的季节变化。进一步分析了表层沉积物的理化性质（TOC 和粒径）对 PCBs 分布的影响。受多种因素的影响，TOC 含量和沉积物粒径对 PCBs 的分布没有明显的影响。PCBs 同系物和异构体分布模式的分析表明，低氯（2-3 个氯原子）PCBs 占主导地位。根据 PCB 同系物分布特征和源解析的主成分分析（PCA）结果，大气沉降和与暴雨相关的地表径流等非点源可能是长江口表层沉积物中 PCBs 的主要来源。
