不同分级标准对高背景值农田土壤重金属质量评价的差异性分析——以尤溪县为例

DifferentClassification Standards of High Background Values of Farmland Soil Quality Evaluation of Heavy Metals Analysis of the Differences—In Youxi County

摘要: 本文选用当前我国现行的土壤环境质量标准、土壤养分分级标准、环境背景值和人体健康风险评价限制四种标准值对矿区农田土壤质量进行评价，同时综合指数评价法对比评价农田土壤重金属污染现状。结果表明：由于国家土壤环境质量标准、土壤养分分级标准值较低，导致区域整体评价结果较差，均无法给予当地农田土壤生态质量正确的评估。以省级区域环境背景值上限值为标准进行评价，7种重金属仍均有超标，其中铜、锌、镉、铅、汞变异系数较大，分别为131%、137%、111%、237%和103%。基于现场调研结果，采用人体健康风险评价法，整体上尤溪县的基本农田土壤受到了轻度污染，健康总风险指数平均值为0.583，达到慢性参考剂量。

Abstract: This paper selected the existing soil environmental quality standard GB, soil nutrient classification standard, environmental background value and limit of four human health risk assessment standards of our country to evaluate farmland soil quality, and comparatively evaluated the heavy metal pollution’s situation of farmland soil by synthesizing index evaluation method. The results showed that due to soil environmental quality standards of the state, soil nutrient grading standard is low, leading to bad evaluation results of regional overall assessment, and the right evaluation of ecological quality of the local farmland soil cannot be given. Evaluating with the standard of the provincial level upper limit of regional environmental background values, there were still 7 kinds of heavy metal exceeding; the variable coefficient of copper, zinc, cadmium, lead, mercury was 131%, 137%, 111%, 237% and 103% respectively, which was large among others. Based on the research results, adopting the human health risk assessment method, it was found that the basic farmland soil was slightly polluted in Youxi County; the average total health risk index was 0.583, reaching chronic reference dose.