湛江市蔬菜地土壤重金属含量特征及生态风险评价

    Characteristics of Heavy Metal Content and Ecological Risk Assessment of Vegetable Soil in Zhanjiang City

    • 摘要:
      目的 了解湛江市蔬菜地土壤重金属含量分布特征,分析其富集特征与生态风险状况,为合理种植蔬菜、农业土壤生态改良提供基础数据与科学依据。
      方法 于湛江市9个县市区采集38个蔬菜地土壤样品,并对其中8种重金属元素含量进行测试,采用潜在生态危害风险指数法进行土壤生态风险评价。
      结果 研究区蔬菜地表层土壤重金属元素含量表现出Cr>Zn>Ni>Cu>Pb>As>Cd>Hg的特征,8种重金属元素含量平均值均超过广东省土壤环境背景值,其中Cd、Hg元素含量分别为背景值的5.53、5.37倍,Ni元素的超标率达21.1%。湛江市蔬菜地表层土壤潜在生态风险指数平均值为386.86,属于强风险,其中Hg、Cd元素的潜在生态风险较大,属于很强风险、强风险,其余元素均为轻微风险;徐闻县为很强风险,廉江市、遂溪县、麻章区、赤坎区和雷州市为强风险,霞山区、坡头区和吴川市为中等风险。
      结论 蔬菜地日常耕作和施用有机肥、化肥等都会导致土壤重金属元素累积,且污染强的蔬菜地附近基本靠近居民点、水沟、高压电线缆等有利于重金属元素沉积的环境。

       

      Abstract:
      Objective The study was carried out to understand the distribution characteristics of heavy metals in vegetable soil in Zhanjiang City and analyze its enrichment characteristics and ecological risk status, with a view to providing basic data and scientific basis for rational vegetable planting and agricultural soil ecological improvement.
      Method 38 vegetable soil samples were collected from 9 counties and districts of Zhanjiang City, and the contents of 8 heavy metals were tested. The potential ecological hazard risk index method was used to evaluate the soil ecological risks.
      Result The contents of heavy metal elements in surface soil of vegetable land in the study area shows the characteristics of Cr > Zn > Ni > Cu > Pb > As > Cd > Hg. The average content of 8 heavy metal elements exceeds the soil environmental background value of Guangdong Province. The contents of Cd and Hg are 5.53 and 5.37 times of the background value, respectively, and the exceeding standard rate of Ni is 21.1%. The average value of potential ecological risk index of vegetable surface soil in Zhanjiang City is 386.86, which belongs to strong risk. Among them, the potential ecological risks of Hg and Cd elements are high, which belong to highly strong risk and strong risk, and the other elements belong to slight risk; Xuwen County belongs to strong risk, Lianjiang City, Suixi County, Mazhang District, Chikan District and Leizhou City belong to strong risks; and Xiashan District, Potou district and Wuchuan City belong to medium risks.
      Conclusion The daily cultivation of vegetable land and the application of organic and chemical fertilizers will lead to the accumulation of heavy metal elements in soil, and the highly polluted vegetable land is basically close to residential areas, ditches, high-voltage cables and other environments conducive to the deposition of heavy metal elements.

       

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