太湖表层沉积物重金属的分布、来源与生态风险评价

对2010年太湖表层沉积物样品进行pH、温度、氧化还原电位、含水率、孔隙度、粒径、总磷和烧失量这8种理化指标和Cu、Zn、Ni、Cr、Pb、Ba、Mn、Co和V这9种重金属含量测定分析.结果表明，太湖表层沉积物重金属含量大小为：Mn>Ba>Zn>Cr>V>Ni>Pb>Cu>Co，且各重金属含量均超过背景值，这9种重金属与太湖流域地质作用紧密相连，同时也受到了不同程度人类活动的影响.通过聚类分析和重金属空间分布分析可知，北太湖段和南太湖段重金属含量均从湖岸向湖心有所减少，西太湖段重金属含量从湖岸向湖心有所增高，湖心区重金属含量分布相对均匀.通过相关性分析可知，不同重金属在不同程度上具有正相关性，反映其具有同一污染来源.通过PCA和PMF分析可知，太湖重金属来源多样，交通和工业复合源是最主要的来源，成岩作用是第二主要来源，农业是第三主要来源.此外，收集分析了2000~2020年太湖表层沉积物重金属的污染情况，通过重金属地累积指数和潜在生态风险指数可知，Cu、Zn、Ni、Cr和Pb的污染程度和潜在生态风险均呈下降趋势.这为太湖今后的重金属污染控制提供了有力的理论支撑.

Distribution, Sources, and Ecological Risk Evaluation of Heavy Metals in Surface Sediments of Taihu Lake

For the surface sediment samples of Taihu Lake in 2010, the eight physicochemical indices of pH, temperature, Eh, water content, porosity, grain size, total phosphorus, and Loss-on-ignition were measured and analyzed, along with the contents of nine heavy metals:Cu, Zn, Ni, Cr, Pb, Ba, Mn, Co, and V. The order of magnitudes of heavy metal content of surface sediments in Taihu Lake was:Mn>Ba>Zn>Cr>V>Ni>Pb>Cu>Co. This suggested that the contents of the nine heavy metals were beyond the background value, which had a close connection to the geology of the Taihu Lake Basin and were influenced by human activity to varying degrees. The clustering analysis and the spatial distribution of the heavy metals revealed that the concentrations of heavy metals in the North and South Taihu Lake sections decreased from the lake shore to the lake center, the concentrations of heavy metals in the West Taihu Lake section increased from the lake shore to the lake center, and the distribution of heavy metals in the center of the lake remained relatively uniform. According to the correlation study, the metal elements were positively correlated with one another to varying degrees, indicating that they originate from the same source of pollution. According to the PCA and PMF analyses, there were some different sources of heavy metals in Taihu Lake, in which the transportation and industrial complex source were the most important sources, the diagenesis was the second major source, and agriculture was the third major source. Furthermore, the heavy metal pollution was evaluated using the geoaccumulation and the potential ecological risk indices. This offers a solid theoretical backing for the future management of heavy metal pollution in Taihu Lake.