新疆于田县农田土壤重(类)金属污染及潜在生态风险评价

【目的】基于新疆于田县土地质量地球化学调查数据,分析8种重(类)金属(Cd、Hg、As、Pb、Cr、Cu、Ni和Zn)元素的含量特征,为该区农田土壤重(类)金属污染防治和风险管控提供科学依据。【方法】依据最新试行的《土壤环境质量-农用地土壤污染风险管控标准(GB15618-2018)》,采用单因子指数法和内梅罗综合指数法进行土壤重(类)金属污染评价,采用潜在生态风险指数法,对土壤中可能存在的潜在生态风险进行定量评价。【结果】于田县484组农田土壤中,有3个取样点超过风险筛选值,无超风险管制值取样点;土壤中除Cd、Cr和Hg元素外,其余重(类)金属元素的平均含量均低于新疆土壤背景值。【结论】土壤中除As元素外,其余重金属单项污染指数均小于1.0,只有As元素在研究区土壤中存在富集现象,土壤可能受到人为污染;内梅罗综合指数结果表明,研究区整体处于安全状态,轻污染和警戒状态分别占0.2%和0.4%;土壤中重(类)金属的潜在生态风险程度都较低,取样点均属于轻微生态风险。

Assessment of Heavy Metal (Metalloid) Pollution and Potential Ecological Risk for Farmland Soil in Yutian County of Xinjiang

【Objective】 Based on the land geochemical survey data in Yutian County, Xinjiang, the content characteristics of eight heavy metals (metalloid) (Cd, Hg, As, Pb, Cr, Cu, Ni and Zn) were analyzed, which might provide scientific basis for the prevention and control of heavy metal (metalloid) pollution and risk control of farmland soil in this area. 【Method】According to the latest trial "Soil environmental quality - risk control standard for soil contamination of agricultural land (GB15618-2018) ", the single factor index method and Nemerow comprehensive index method were used to evaluate the pollution of heavy metals (metalloid) in soil, and the potential ecological risk index method was used to conduct quantitative evaluation of potential ecological risk in soil.【Result】Among the 484 groups of farmland soil in Yutian County, the three sampling points exceeded the risk screening value, and there were no sampling points exceeding the risk control value. In addition to Cd, Cr and Hg, the average contents of other heavy metal (metalloid) elements in soil were lower than the background values in Xinjiang.【Conclusion】In addition to As element, the single pollution index of heavy metals in the soil were less than 1.0, indicating that only As element was enriched in the soil of the study area, and the soil might be contaminated by human activities; the results of Nemerow comprehensive index showed that the study area was in a safe state, with light pollution and alert status accounting for 0.2% and 0.4% respectively; the potential ecological risk of heavy metals (metalloid) in soil were low, and the sampling points were all in the light ecological risk.