成都城郊典型蔬菜中重金属元素的富集特征

THE CHARACTERISTICS OF HEAVY METAL ENRICHMENT IN REPRESENTATIVE VEGETABLES IN CHENGDU

通过成都城郊典型蔬菜莴笋、红薯及其根系土的研究,探讨了重金属在蔬菜内的富集特征。研究表明:茎叶类蔬菜对重金属的富集能力总体上高于块茎类蔬菜,蔬菜中高富集元素为Cu、Cd、Zn,中等富集元素为Hg、As、Cr,低富集元素为V、Pb;蔬菜根系土除As外,红薯根系土中重金属平均含量高于莴笋根系土对应元素含量,其中莴笋根系土Cd、红薯根系土Cd,Zn超过国家土壤二级质量标准;对照无公害蔬菜质量标准,莴笋茎中重金属元素无超标,莴笋叶Pb,Hg部分超标,红薯Pb,Cr部分超标;与前人的研究对比,蔬菜叶中重金属含量有较大幅度的增加,显示大气环境污染有加剧的趋势。

Based on research on lettuce, ipomoea batata and root soil in Chengdu, the characteristics of heavy metal enrichment in vegetables are described. The results showed that heavy metal enrichment in leaves is higher than in tubers; the contents of heavy metals in root soil show a reverse trend except for As. The highest enrichment elements in the vegetables are Cu, Cd, Zn; moderate enrichment elements in the vegetables are Hg, As, Cr; the lower enrichment elements in the vegetables are V and Pb. The contents of Cd in lettuce root soil and Cd, Zn in ipomoea batata root soil exceed the country soil II quality standard. Compared with vegetable harmless quality standard, the contents of Pb, Zn in lettuce leaf and Pb, Cr in ipomoea batata partly exceed the standard. In combination with the previous research results, it is found that the contents of heavy metals in vegetable leaves have increased greatly, indicating air pollution air is deteriorating.