镉从农业土壤向人类食物链的迁移

Transfer of Cadmium from Agricultural Soils to Human Food Chain

综述了镉在环境中的行为，在土壤－植物－人类系统中的迁移。由于粮食作物是镉进入人类食物链的主要来源，因此土壤污染的危害是全球性的，对决定农业系统中镉迁移动力学的关键过程、粮食作物中的镉含量、影响镉植物有效性的各类因子作了综述和讨论。此外，镉在食物中的形态可能影响其有效性及在人体内的分布，故对镉的存在形态作了介绍，镉在植物中主要与第Ⅲ类金属蛋白结合，以植物金属螯合蛋白形态存在．过量接触镉将严重危害人体健康．

Cadmium is not an essential element for biological organisms, but it is highly toxic to plant, animal and human at excess levels. The behaviors of cadmium in the environment and transfer of cadmium in soil-plant-human system were reviewed. As food crops are main sources for cadmium entering into human food chain, soil pollution is world-wide harmful.This review dealt with the key processes determining cadmium dynamics in agricultural system,cadmium concentrations in edible parts of major food crops, and factors affecting cadmium bioavailability. In addition,cadmium forms in food may influence availability and distribution of cadmium in human body, so cadmium forms in food were also discussed in this paper. Cadmium in plants was mainly complexed with metallothioneine Ⅲ, i. e. phytochelatin.Excessive level of cadmium was very harmful to human health.