上海菜区土壤和蔬菜中重金属含量及其相互关系

1981～1982年在上海菜区采集了229个土壤和327个蔬菜样品。土壤中镉平均含量比对照医增加2.7倍(最高值为13.5毫克/公斤)、锌增加67.3%、铜56.6%、铅44.6%、铬20.4%和汞22.7%,砷与对照相近。污染土壤中多种重金属元素同时增高。在土壤元素相关矩阵中具有极显著意义(P<0.01)的元素对达95.4%.不论对照区或菜区,多数情况下,菠菜、马铃薯、莴苣各种重金属含量较高;黄瓜,甘蓝和茭白较低。蔬菜中锌、砷、铬、铅和铜的含量一般大大低于暂定容许含量。除砷外,青菜和土壤的重金属含量显著相关。在研究的七种元素中,土壤中镉的提取百分率最高,富集系数最大,青菜和土壤的相关系数最好。土壤中重金属含量的增加主要是应用受重金属污染的水及污泥。

THE CONTENT OF HEAVY METAL IN SOILS AND VEGETABLES AND RELATIONSHIP BETWEEN THEM IN VEGETABLE-GROWING REGION OF SHANGHAI

229 soil samples and 327 vegetable samples were coll cted in vegetable-growing region of Shanghai in 1981-1982.The average Cd content in soil increased 2.7 times (maximum value was 13.5mg/kg)and 67.3% for Zn,56.6% for Cu,44.6% for Pb, 20.4% for Cr and 22.7% for Hg as compared with control region except for As. Simultaneously increased various heavy metals were found in contaminated soils. 95.4% of pair of element were significant correlation at 0.01 level in matrix of soil elements.Both control and vegetable-growing region,in most cases,the content of heavy metal in spinach,potato,lettuce were higher where as cucumber,cabbage, watershoot were lower.The content of-Zn,As,Cr,Pb and Cu in vegetable normally were much less than tantatively allowed content. There were significant correlations in content of heavy metal between soil and greenvegetable except for As.In elements tested,the extratable percentage of Cd in soils was the highest and good correlation coefficient was obtained as far as soil and green- vegetable were concerned.The increase of heavy metals in soils was mainly caused by application of contaminated water and seawage sludge high in heavy metals.