杭州市主要地区农田土壤重金属污染评价及关联特征研究

对杭州市郊4个农田土壤中铜（Cu）、锌（Zn）、镉（Cd）、铅（Pb）含量进行测定分析，并参照不同评价方法和标准对其土壤污染状况做出评价．结果表明：蒋村土壤具有相对较高的全量及有效态Cu、Zn、Pb含量，4个地区土壤中均未有Cd的检出．单项污染指数评价表明，蒋村土壤已受到Zn的明显污染；综合污染指数评价表明，乔司和下沙的土壤为清洁水平，七堡土壤属于尚清洁水平，而蒋村土壤污染等级为轻污染，污染水平为作物已受到污染．从综合累积指数评价发现，乔司和下沙土壤重金属为高度累积，七堡和蒋村土壤重金属达到严重累积程度．通过土壤重金属与理化性质相关系数分析可知，土壤的pH值、速效N、P、K及有机质含量及阳离子交换量均与土壤重金属全量及有效态重金属含量呈显著相关关系，据此推测4个地区土壤中重金属可能主要源自化肥及有机肥的施用，应予以高度重视，尤其是杭州蒋村土壤重金属的污染风险更应予以关注．

Researches on Assessment and Correlation of Heavy Metal Contamination in Agricultural Soils of Hangzhou

Using the flame atom absorption spectrographic methods, the paper determines the contents of heavy metals （Cu, Zn, Cd and Ph） in Hangzhou agricultural soils and assesses for heavy metal pollution referring to the country soil environmental quality standards （GB15618-1995）. The results show that contents of total or available of heavy metals （Cu, Zn and Pb） in Jiang Cun district are relatively higher. The single pollution index indicates the soils in Jiang Cun district has been obvious polluted by Zn. The integrated pollution index points out that the agricultural soil of Qiao Si and Xia Sha district belong to clean level while the agricultural soil of Qi Bao district and Jiang Cun district belonge to security level and low-grade pollution level. The integrated accumulation index indicates the soil of Qiao Si and Xia Sha district belong to highly accumulation level and the soil of Qi Bao and Jiang Cun district has reached seriously accumulating degree. According to the correlation coefficient between heavy metal contents and physi-chemical properties of soil, the pH, available N,P,K, organic matter and exchange capacity of cation are significantly correlated to the total and available heavy metals content in the soil, which suggest that heavy metals in the soil may derive from the usage of chemical or organic fertilizer and much more attention should be paid on the potential heavy metal pollution risk in agricultural soil of Hangzhou, especially Jiang Cun district of Hangzhou.