佛山市某工业区周边蔬菜重金属富集特征的研究

Accumulation of Heavy Metals in Vegetables Grown Around an Industrial Area in Foshan

采集佛山市某工业区周边农田种植的蔬菜可食部分和对应的土壤耕层样品,分析了蔬菜和土壤中Zn、Cu、Pb、Cd含量;根据国家食品中重金属限量标准,评价了蔬菜中重金属污染状况,并研究了不同种类蔬菜中重金属的积累特性.结果表明,除2个蕹菜样品中Pb和1个葱样品中Cd外,所有蔬菜样品中Zn、Cu、Pb、Cd含量均低于国家食品限量标准;不同重金属元素在蔬菜中的富集系数大小为Cd>Zn>Cu>Pb;不同种类蔬菜对土壤重金属的富集系数为叶菜类>瓜类;蔬菜Zn含量与土壤Zn含量具有显著相关性,但蔬菜Cu、Pb和Cd含量与土壤中对应元素含量没有显著相关性.就食品安全而言,瓜类蔬菜比叶菜类蔬菜更适宜在该工业区周边农田种植.

The concentrations of Zn, Cu, Pb and Cd in edible part of vegetables and corresponding surface soil samples collected from the fields near an industrial area in Foshan were investigated to evaluate safety for human consumption and calculate accumulation factors, i.e. the ratio of metal concentration （fresh mass） in edible part of vegetable to the total metal concentration in soil. The results indicated that the contents of Zn, Cu, Pb and Cd in vegetables were less than the national tolerance limit in foods with the exception of two water spinach （Ipomoea aquatica） samples for Pb and one spring onion （Alliumfistulosum） sample for Cd. The accumulation factors of Zn, Cu, Pb and Cd in vegetables decreased in the order of Cd 〉 Zn 〉 Cu 〉 Pb. The accumulation factors of heavy metals for different vegetable species were significantly diffrerent, and the order was leafy vegetables 〉 gourd vegetables. Significant correlations did not exist between the heavy metal concentrations in soil and vegetable samples excepting Zn. With respect to food safety for human consumption, gourd vegetables are more suitable grown than leafy vegetables in this area.