宜宾市某茶园土壤潜在毒性元素污染评价及源解析

为更好的揭示宜宾市屏山县某茶园土壤PTEs污染现状与来源,通过对研究区样品采集和检测分析,利用内梅罗指数、地积累指数和潜在生态风险指数对茶园土壤中7种潜在毒性元素(PTEs)（Cd、As、Cr、Cu、Pb、Ni和Zn）进行了污染评价,并以多元统计与空间分析相结合的手段对其进行了溯源分析。结果表明：茶园土壤中7种PTEs浓度只有Cd超过农用地土壤筛选值;对比四川省土壤背景值,Cd超标倍率88.45倍,且内梅罗污染指数、地积累污染指数及综合潜在生态污染风险指数的平均值为7.65、3.38和1262.06,表明茶园土壤中PTEs污染严重且潜在生态风险高。多元统计与污染空间分析得出对于同一组分中Cd、Cr、Ni和Zn的富集可能为硫铁矿开采导致;Pb主要为硫铁矿的采选冶燃煤大量使用导致;As除了燃煤使用外,还与肥料的使用有关;研究区早期小龙溪沿岸土法造纸厂生产活动造成水体中Cu富集和周边土壤酸化。茶园土壤中PTEs污染程度空间分布特征表明Cd为主要风险来源,并且Cd对于整个研究区PTEs污染起到控制性作用。

Evaluation and Source Analysis of Soil Potential Toxic Elements Pollution in Tea Garden in Yibin City

To reveal the current status and source of PTEs pollution in tea garden soil in Pingshan County, Yibin City, through the collection and detection of samples, the pollution assessment of 7 potentially toxic elements (PTEs) (Cd, As, Cr, Cu, Pb, Zn, Ni) was carried out by using the Nemerow index, geo-accumulation index and potential ecological risk index, and the source analysis was conducted by multivariate statistics and spatial analysis. The results showed that among the concentrations of the 7 PTEs, only Cd exceeded the screening value of agricultural land in the tea garden soil. Compared with the soil background value in Sichuan Province, the Cd over-standard rate was 88.45 times, and the average value of Nemerow pollution index, geo-accumulated pollution index and comprehensive potential ecological pollution risk index was 7.65, 3.38 and 1262.06 respectively, indicating that tea garden soil was seriously polluted, and the potentially ecological risk was high. Multivariate statistics and pollution spatial analysis showed that the enrichment of Cd, Cr, Ni and Zn might be caused by pyrite mining; Pb was mainly caused by the large-scale use of coal in the mining and smelting of pyrite. In addition to burning coal, As was also related to the use of fertilizers; the early generation of the paper mills along the Xiaolongxi caused Cu enrichment in the river and acidification of the surrounding soil in the study area. The spatial distribution characteristics of PTEs pollution indicated that Cd was the main source of risk, which had a controlling effect on PTEs pollution in tea garden soil in Yibin.