天津市污灌区重金属在土壤—蔬菜体系中的迁移积累

Transfer and Accumulation of Heavy Metals in Soil-Vegetable System at Sewage Irrigated Areas in Tianjin

对天津市污灌区若干重污染点的土壤及蔬菜中重金属污染状况进行了调查,利用BCR(Community Bureau of Refer-ence)连续提取法测定了不同形态重金属的含量,以及重金属在蔬菜各部分的分布,初步探讨了重金属在土壤—蔬菜系统中迁移富集规律。结果表明:Cd,Hg最易被蔬菜富集,Ni则不易在蔬菜中累积;芹菜、油麦菜等叶菜对重金属富集能力较强,萝卜则最不易富集重金属。土壤中重金属含量是影响其在蔬菜中富集的主要因素,并与蔬菜根部重金属含量呈一定的相关性,而利用BCR连续提取的可溶态重金属只能预测Cd的生物有效性。

Heavy metals in soil and vegetables from seriously polluted areas irrigated with sewage water in Tianjin were investigated.The chemical form of the heavy metals in soil was elucidated by BCR(Community Bureau of Reference)successive extraction method,and the heavy metal contents in different parts of the vegetables were measured.The transfer and accumulation of heavy metals from the soil to the vegetables were discussed primarily.The results showed that cadmium and mercury were most easily accumulated in vegetables,while nickel most difficultly.Moreover,the heavy metals were most easily accumulated in celery and lettuce,and least in radish.The content of heavy metals in soil was the main factor affecting their accumulation in vegetables,and it was correlative with the heavy metal content in vegetable root significantly,whereas the dissolved fraction measured by BCR could only predict the bioavailability of cadmium.