矿区农田土壤重金属污染评价与研究

Assessment and Research of Heavy Metals Pollution in Farmland Soil from Mining Areas

以贵州六盘水市2个矿区周边农田土壤为研究对象,对土壤重金属进行含量及分布特征分析。采用污染负荷指数法、潜在生态风险评价法和地积累指数法对其污染状况进行评价。结果表明:2个矿区农田土壤Pb、Cd、Hg、Cu的含量最大值均超出了贵州省土壤背景值,Cu的污染最严重,2个矿区的含量均值分别是背景值的5.54倍和4.12倍;2个矿区农田土壤重金属的含量分布总体上呈现在煤矸石堆放场、矿区洗煤池附近农田土壤中重金属元素的含量高于远离矿区的外围农田的现象。矿区WJZ和矿区ZS重金属元素的污染系数均值由高到低均呈现Cu>Hg>Pb>Cd>As的现象,土壤采样点整体的污染负荷指数分别为1.39和0.75,即分别呈现中等污染和无污染的状况;Cu、Pb、Cd元素的来源可能受人为采矿活动的影响,Hg、As元素的来源可能受人类活动和成土母质的共同影响。

Two typical mining areas soils in Liupanshui were took as the research object to analyze the contents and dis tribution characteristics of heavy metals of the farmland soils. Their pollution status were assessed by the pollution load index, Hakanson ecological risk index and geological cumulative index. The results showed that the maximum contents of Pb,Cd, Hg and Cu in farmland soils of the two mining areas exceeds the soil background values of Guizhou Province,and the pollu tion of Cu is the worst. The average contents of heavy metals in farmland soils of the two mining areas are 5.54 times and 4.12 times of the background values,respectively. The distribution of heavy metals in farmland soils of the two mining areas gener ally presented that the contents of heavy metals in farmland soils near coal gangue dump and coal wash pool are higher than that of the farmland far away from the mining area. The average pollution coefficients of heavy metal elements in WJZ and ZS of mining area show the phenomenon of Cu > Hg > Pb > Cd > As from high to low. The overall pollution load index of soil sam pling points are 1.39 and 0.75,showing moderate pollution and non-pollution,respectively. The sources of Cu,Pb and Cd el ements may be affected by human mining activities,and the sources of Hg and As elements may be affected jointed by human activities and soil-forming materials.