湖北利川耕地土壤重金属分布及风险评价

Distribution and Risk Assessment of Heavy Metals in Farmland soil of Lichuan, Hubei Province

摘要: 采集、检测、统计分析了湖北省利川市338个耕地土样的镉、砷、铬、铅、汞等重金属含量，并运用单因子指数、地累积指数和潜在生态危害单项指数对单个重金属污染程度进行了评价，还运用内梅罗指数、潜在生态危害指数进行了重金属污染程度的综合评价。结果表明，利川耕地镉存在轻微污染，且污染指数最高、程度最重，均值超过GB15618-2018标准制定的最严风险筛选值，56.80%的样点处于黄区，1个样点为红区；其次为砷，有17.16%的样点处于黄区；铬、铅、汞基本处于绿区，未造成污染；综合评价内梅罗指数为轻微污染、潜在生态危害指数为低污染水平。5种重金属间相关性极显著，可能来源具有相似性；镉与土壤有机质、pH极显著相关；铅与土壤有机质显著相关、与pH极显著相关；砷与土壤pH极显著相关。这为利川优质高山水稻、高山蔬菜、地道药材、“利川红”茶叶等特色产业的区域规划和健康发展提供了重要依据。

Abstract: The content of cadmium, arsenic, chromium, lead, mercury and other heavy metals in 338 cultivated soil samples from Lichuan City, Hubei Province was collected, detected, and statistically analyzed. The single factor index, land accumulation index, and potential ecological hazard single index were used to evaluate the degree of individual heavy metal pollution. The Nemero index and potential ecological hazard index were also used to comprehensively evaluate the degree of heavy metal pollution. The results showed that there was slight cadmium pollution in the farmland of Lichuan, with the highest pollution index and the heaviest degree, with an average exceeding the strictest risk screening value set by the GB15618-2018 standard. 56.80% of the sampling points were in the yellow area, and one sampling point was in the red area; Next is arsenic, with 17.16% of the samples located in the yellow zone; Chromium, lead, and mercury are mostly in the green zone and have not caused pollution; The comprehensive evaluation shows that the Nemero index is slightly polluted and the potential ecological hazard index is at a low pollution level. The correlation between the 5 heavy metals is extremely significant, and their sources may be similar; Cadmium is significantly correlated with soil organic matter and pH; Lead is significantly correlated with soil organic matter and extremely significantly correlated with pH; Arsenic is significantly correlated with soil pH. This provides an important basis for the regional planning and healthy development of characteristic industries such as high-quality high-altitude rice, high-altitude vegetables, authentic medicinal herbs, and “Lichuan Red” tea in Lichuan.