应用三种方法评价湖南省郴州市东河流域耕地土壤环境质量
Evaluation of soil environmental quality of cultivated land in the Donghe River Basin of Chenzhou City, Hunan Province by three methods
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摘要:
背景 耕地土壤重金属污染影响作物产量和品质，影响地下水质量、生态安全以及人体健康。
目的 分析湖南省郴州市东河流域耕地土壤重金属元素铬（Cr）、铜（Cu）、锌（Zn）、砷（As）、镉（Cd）和铅（Pb）的污染状况，评价耕地土壤环境质量。
方法 采集郴州市东河流域耕地土壤16份，采用电感耦合等离子质谱法测定各采样位点中Cr、Cu、Zn、As、Cd和Pb的含量。选用内梅罗综合污染指数法（评价指标包括内梅罗综合污染指数和单项污染指数）、地质累积指数法和潜在生态风险指数法方法评价土壤环境质量。
结果 研究区域耕地土壤样品中Cr、Cu、Zn、As、Cd和Pb的平均含量分别为58.25、49.50、273.88、137.76、2.92和672.29 mg·kg−1，Cu、Zn、As、Cd和Pb平均值均超过了湖南省土壤元素背景值。土壤As、Cd、Pb和Zn的内梅罗单项污染指数分别为4.40、9.74、5.85、1.15，As和Pb的污染位点分别达到93.75%和81.25%；土壤As、Cd、Pb和Zn的地质积累指数分别为2.11、3.71、2.97、0.58，土壤处于Cd偏强污染，As和Pb中度污染，Zn轻度污染；土壤Cr、Cu、Zn、As、Pb和Cd的潜在生态危害指数分别为1.63、9.07、2.90、87.75、113.18和695.76，Cd有81.25%位点呈现偏强污染及以上污染程度，62.50%的位点Pb污染等级在中度污染及以上等级。内梅罗综合污染指数为7.72，综合潜在生态风险指数为910.29，整体表现为重度污染和强生态风险。
结论 不同评价方法评价结果存在一定差异。湖南省郴州市东河流域耕地土壤重金属污染程度高，Cd、As和Pb为主要污染元素。
Abstract:Background Heavy metal pollution in cultivated land will affect crop yield and quality, as well as groundwater quality, ecological security, and human health.
Objective To analyze the pollution status of heavy metal elements such as chromium (Cr), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), and lead (Pb) in cultivated soils of the Donghe River Basin in Chenzhou City, and to evaluate the environmental quality of local cultivated soil.
Methods A total of 16 samples of cultivated soil from the Donghe River Basin in Chenzhou City were collected, and the contents of Cr, Cu, Zn, As, Cd, and Pb in the samples were determined by inductively coupled plasma mass spectrometry. The Nemerow comprehensive pollution index method (the evaluation indicators included both Nemerow comprehensive pollution index and single pollution index), the geological accumulation index method, and the potential ecological risk index method were used to evaluate the soil environmental quality.
Results The average levels of Cr, Cu, Zn, As, Cd, and Pb in the soil samples in the study area were 58.25, 49.50, 273.88, 137.76, 2.92, and 672.29 mg·kg−1, respectively. The average values of Cu, Zn, As, Cd, and Pb were all exceeded the background values of soil elements in Hunan Province. The single pollution indices of As, Cd, Pb, and Zn in soil were 4.40, 9.74, 5.85, and 1.15 respectively. The contamination of As and Pb reached 93.75% and 81.25% respectively. The geological accumulation indices of soil As, Cd, Pb, and Zn were 2.11, 3.71, 2.97, and 0.58, respectively, which showed heavy Cd pollution, moderate As and Pb pollution, and slight Zn pollution. The potential ecological hazard indices of soil Cr, Cu, Zn, As, Pb, and Cd were 1.63, 9.07, 2.90, 87.75, 113.18, and 695.76. 81.Twenty five percent of Cd samples showed heavy pollution and above, and 62.50% of Pb samples had moderate pollution and above. The Nemerow comprehensive pollution index was 7.72, which belonged to heavy pollution; and the comprehensive potential ecological risk index was 910.29, which belonged to high ecological risk.
Conclusion There are certain differences in the results of different evaluation methods. The cultivated soils of the Donghe River Basin in Chenzhou City, is seriously polluted by heavy metals, and Cd, As, and Pb are the main polluting elements.
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