丹江口水库新增淹没区农田土壤重金属源解析

丹江口水库是南水北调中线工程水源地，研究新增淹没区农田土壤重金属分布、富集特征并解析其来源，对水库的水质安全保障具有重要意义.通过测定新增淹没区169个农田土壤样品中8种重金属（Cd、Cr、Cu、Ni、Pb、Zn、As、Mn）含量，对土壤重金属污染状况进行了分析.结果表明：Cr的平均含量（45.11mg/kg）均低于库区土壤环境背景值，而Cd的平均含量（1.04mg/kg）均高于背景值；除Cu外，Cd、Cr、Ni、Pb、Zn和As在丹库的空间变异性较强，变异系数分别为0.58、0.72、0.58、0.74、0.35、1.12；Cd和As是丹江口水库新增淹没区的主要污染元素，其中Cd的富集系数高达10.3，中度以上污染区为86.6%，As中度及以上污染区为2.6%；新增淹没区农田土壤重金属来源主要为自然源（Cr、Cu、Ni、Pb、Zn、Mn）、农业源（As）、工业和生活源（Cd），贡献率分别为44.7%、15.9%和15.4%.

Source apportionment of heavy metals in farmland soil from new submerged area in Danjiangkou Reservoir

The Danjiangkou reservoir is the water source for the Middle Route Project under the South-to-North WaterTransfer Scheme. Heavy metal pollution assessment in the new submerged area is critical for water conservation. Therefore, it is essential to assess heavy metal pollution in the new submerged area. In this study, we determined the contents of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn, As, Mn), in which 169soil samples of the new submerged area were collected, and we analyzed the source and enrichment of heavy metals using enrichment factor and multivariate statistical analysis. The concentration of Cr(45.11mg/kg) was lower than the background value of the reservoir area, while the concentration of Cd(1.04mg/kg) was higher than the background value within the sampling area. The spatial analysis showed that the concentrations of Cd, Cr, Ni, Pb, Zn and As (except for Cu) in the Dan River Reservoir were higher than the Han River Reservoir, the coefficient of variation were 0.58, 0.72, 0.58, 0.74, 0.35 and 1.12, respectively. Cd and As were the dominant contaminated element of the new submerged area in the Danjiangkou reservoir. The enrichment factor value of Cd was 10.3, and the area moderately contaminated or above of Cd and As occupied 86.6 percent and 2.6 percent, respectively. The results revealed that As, Ni, Cu, Pb and Cr were the main input of natural sources, whereas the agricultural production activities, industrial production activities and domestic waste were the sources of the accumulation of As and Cd.