贵州省麻江县蓝莓基地土壤重金属污染及风险评价

为了研究麻江县蓝莓基地土壤中8种重金属元素(Hg、Cd、As、Pb、Cu、Ni、Cr和Zn)的分布特征、污染程度、潜在生态风险及其来源。采用ICP-MS和AFS分别测定了麻江县6个蓝莓基地18件土壤样品中的8种重金属元素含量,并采用地累积指数法、内梅罗污染指数法、富集因子法、潜在生态污染指数法对蓝莓基地土壤重金属元素富集程度和潜在生态风险进行了评价,同时结合相关性分析和聚类分析对麻江蓝莓基地土壤重金属来源进行了探讨。结果表明,麻江蓝莓基地土壤Hg、Cd、As、Pb、Cu、Ni、Cr和Zn的平均值分别为0. 24、0. 30、35、35、22、27、62、79 mg/kg,Hg、As和Pb平均值高于贵州省土壤背景值,Hg和As污染严重。地累积指数法、内梅罗污染指数法、富集因子法、单项污染指数法的评价结果基本一致,其评价结果表明,麻江蓝莓基地土壤中的Hg、As、Pb受到了不同程度的污染。综合污染指数法评价结果表明,陡坡坪、乌卡坪和白竹林蓝莓基地土壤已受到重金属的轻度污染;陈家山、乌羊麻和甘溪蓝莓基地土壤已受到重金属的中度污染。潜在生态污染指数法评价结果表明,陡坡坪、乌卡坪和白竹林蓝莓基地土壤8种重金属存在轻微潜在生态风险,陈家山、乌羊麻和甘溪蓝莓基地土壤8种重金属存在强潜在生态风险。相关性分析和聚类分析表明,Ni、Zn、Cu、Cr和Cd相关性显著并聚为一类,主要来源于自然地质背景; As和Pb相关性极显著并聚为一类,主要受动物粪便、农药、汽车尾气等复合因素的影响; Hg与其他7种重金属之间无相关或相关性不显著,单独聚为一类,主要来源于燃煤。

Ecological Risk Evaluation of Heavy Metal Contamination in Blueberry Planting Soil of the Majiang County, Guizhou, China

In order to study distribution characteristics, pollution degree, potential ecological risks and pollution sources of heavy metal elements in soil of blueberry planting bases in the Majiang county, Guizhou, concentrations of 8 heavy metals (Hg, Cd, As, Pb, Cu, Ni, Cr and Zn) in 18 soil samples from 6 blueberry planting bases were determined by ICP-MS and AFS methods. The pollution degree and potential ecological risk of these heavy metals in soil of blueberry planting bases was evaluated by approaches of geoaccumulation index, Nemero pollution index, enrichment factor and potential ecological risk index. The source of heavy metals was discussed by correlation analysis and cluster analysis. The results showed that average contents of Hg, Cd, As, Pb, Cu, Ni, Cr and Zn in target soils were 0.24, 0.30, 35, 35, 22, 27, 62, and 79 mg/kg, respectively. The results from geo-accumulation index, Nemero pollution index, enrichment factor, and individual pollution index were similar, Hg, As, and Pb showed varying degrees of pollution. The evaluation results of the comprehensive pollution index method showed that soils of blueberry planting bases in Doupoping, Wukaping, and Baizhulin had been contaminated slightly by heavy metals; soils of blueberry planting bases in Chenjiashan, Wuyangma, and Ganxi had been contaminated moderately by heavy metals. The evaluation results of the potential ecological pollution index showed that potential ecological risks of 8 heavy metals in soils of Doupoping, Wukaping and Baizhulin were slight, and in soils of Chenjiashan, Wuyangma and Ganxi were serious. The correlation analysis and cluster analysis showed that Ni, Zn, Cu, Cr and Cd correlated significantly and might be grouped into one category originated from geological backgrounds; As and Pb correlated very significantly and might be grouped into one category originated from pollutions of animal faeces, pesticides, and automobile exhaust; Hg had no or no significant correlations with other 7 heavy metals and might be originated from coal combustion.