菜地土壤和蔬菜中几种重金属的分布特征

重庆市不同区县菜地土壤和蔬菜中重金属含量差异明显。通过对不同区县土壤和蔬菜中重金属的聚类分析发现土壤中重金属含量无明显的区域分布规律，但蔬菜中重金属含量区域分布规律明显，说明蔬菜中重金属污染受大气影响明显。相关性分析表明同地点土壤和莴笋重金属Cr、Ni、Cu、Zn、As、Cd、Pb、Hg均无显著相关性，说明蔬菜莴笋重金属同土壤关系不大。不同区域土壤中重金属含量差异不大，但远郊区蔬菜中重金属含量较小，可能与远郊区大气污染相对较轻有关。

STUDY ON THE DISTRIBUTION RULES OF HEAVY METALS IN SOILS AND VEGETABLES ON VEGETABLE FARMS

Significant differences are found for the contents of heavy metals in soils and vegetables on vegetable farms in different counties of Chongqing. Cluster analysis showed that the contents of heavy metals in soils have no obvious regional distribution rules in different counties, but in vegetables have obvious regional distribution rules. It is clear that the pollution of heavy metals in vegetables is affected by air pollution. The correlation analysis demonstrated that the contents of Cr, Ni, Cu, Zn, As, Cd, Pb and Hg in soils and vegetables have no correlation in the same area. It is shown that the contents of heavy metals in asparagus lettuce are not higher than those in soils. The contents of heavy metals in soils are of little difference from place to place, but those of vegetables are lower in the remote outskirts. It seems to be related with the light air-pollution.