图们江流域湿地土壤重金属污染特征

以中国一侧图们江流域为研究区,选取该流域湿地为研究对象,采集85个表层土壤样本,对Cr、Ni、Cu、Zn、As、Cd和Pb这7种重金属含量进行测定。利用主成分分析法探索污染来源,通过地质累积指数与内梅罗指数相结合的综合指数法(GNI)及潜在生态危害指数法(RI)并结合GIS技术对土壤重金属污染程度及空间分布特征进行分析。结果表明,图们江流域湿地土壤7种重金属中Cu、As、Cd和Pb污染情况显著。Cu、Zn、As和Pb主要受人为因素影响,Cr、Ni和Cd主要由自然因素影响。图们江流域湿地土壤重金属新综合污染指数评价总体上基本处于偏中度到中度,其中As污染较为严重;潜在生态危害污染评价总体上处于轻度;其中Cd污染较为严重。从整体流域分界上看,污染程度表现为中游下游上游;从整体空间分布上看,污染程度由西向东表现为先升高在降低,由北向南表现为降低。

Characteristics of heavy metal pollution in wetland soil in Tumen River Basin

Eighty-five surface soil samples were collected from the Tumen River Basin of China and seven heavy metals including Cr, Ni, Cu, Zn, As, Cd and Pb were determined. Principal component analysis (PCA) was used to explore the pollution sources of heavy metals.The level and spatial distribution of heavy metals pollution were evaluated using the comprehensive index method (Geoaccumulation index and Nemero index, GNI) and the potential ecological hazard index method (RI) via GIS. Result showed that in this region, Cu, As, Cd and Pb pollution was significant. Pollutions of Cu, Zn, As and Pb were affected by human factors, while pollutions of Cr, Ni and Cd were affected by natural factors. The level of pollution from moderate to partial in GNI, in which As pollution was significant. The pollution level was slight in RI, but Cd pollution was significant. In the whole watershed boundary, the midstream was the most polluted area, followed by the downstream. According to the spatial distribution of the pollution, the level of pollution increased first and then decreased from west to east, while the pollution decreased continuously from north to south.