贵州省地道药材GAP基地土壤重金属含量及污染评价

Heavy Metal Contents and Pollution Evaluation of Soils in Chinese Medicinal Herbs GAP Bases in Guizhou Province

对贵州省11个地道中药材GAP基地土壤中的5种重金属含量进行调查分析，分别以国家土壤环境质量二级标准和区域土壤重金属背景值作为标准对其单项和综合污染指数进行分析评价。结果表明：调查区域内各基地重金属含量水平差异很大，土壤重金属含量的变异系数6．6％～70．4％。调查区域内基地土壤受到了不同程度的污染，部分土壤达不到国家环境质量二级标准的要求。以国家土壤环境质量二级标准作为评价标准的评价结果为：单项污染指数最大2．5，综合污染指数最大1．9，受污染基地占27.3％。以区域土壤重金属背景值作为标准评价结果为：单项污染指数最大4．3，综合污染指数最大3．3，受污染基地占54．5％。在重金属污染因子中，Cd是主要污染因子，其次是Cu、Hg、As。

Soils of 11 Chinese medicinal herbs GAP bases in Guizhou Province were investigated for heavy metal contents and further analyzed for single element pollution indices and integrated pollution index on the basis of Grade II criteria of the National Standard for Soil Environmental Quality and background values of soil heavy metals in the region. Results showed that the GAP bases varied greatly in soil heavy metal content. Their variance coefficient ranged from 6.6% to 70.4%, indicating that the soils of the GAP bases were polluted by heavy metals to a varying extent. Some soils failed the Grade II Criteria of the National Standard for Soil Environmental Quality. The evaluation based on the national standard showed that the max single element pollution index was 2.5, the max integrated pollution index 1.9, and the polluted area accouhted for 27.3%. The evaluation based on the background values of heavy metals in the region showed that the max single element pollution index was 4.3, the max integrated index 3.3, and the polluted area reached 54.5%. The major polluting factor of the soils was Cd, followed by Cu, Hg and As.