北京东郊作物土壤系统中重金属的迁移、分布、积累

 本文研究了北京东郊污灌区重金属在作物—土壤中的迁移、分布、积累规律，证实本区蔬菜中汞含量比粮食作物约大3—15倍，比水果约大6—200倍。麦粒、糙米中的Cu、Hg、Cd、Pb、Ni的含量与土壤含量相关性不显著。架豆中重金属含量与土壤中重金属含量的相关性，只有Zn，Pb达显著水平。白菜土有机质含量与重金属含量相关性达显著水平，而白菜的重金属含量与土壤的重金属含量相关性却不显著。说明除了土壤中重金属的总量外，有效态含量的多少，是影响本区作物吸收积累重金属的主要因素。 本区施污泥的土壤和生长的作物Cd／Zn大部小于1%、盆栽试验证明：施用本区污泥污水对水稻生长发育的影响比施污泥灌清水的影响大些，因此，施用含重金属污泥时，最好不要超过5000斤／亩。大田和室内模拟试验证明：重金属从土壤中迁移到植物，由植物带走输出的量极少，其中以带走输出的Hg、Cd，As相对较多，带走输出的Pb、Cr相对的少些。

THE TRANSTOCATION, DISTRIBUTION AND ACCUMULATION OF HEAVY METALS IN CROP-SOIL SYSTEM IN THE EASTERN SUBURBS OF BEIJING

This paper has studied the regularity of translocation, distribution and accumulation of heavy metals in crop-soil system in the sewageirrigated area in the Eastern Suburbs of Beijing. The result of the experiments indicates that the mercury content in vegetables is about 3—15 times more than in crops and about 16--200 times more than in fruits. The relativity of Cu, Hg, Cd, Pb, Ni content in wheat and brown rice and in soil is not apparent. The relativity of heavy metal content in soybeans and in the soil, only Pb and Zn reached a high significant level. In the soil where Chinese cabbages were grown, the relativity of organic matter content and heavy metal content reached a significant level. However, the relativity of the content of them in the cabbages was not evident. This indicates that apart from the total content of heavy metals in the soil, the amount of their available content was the main factor which influenced the absorption and accumulation of heavy metals by the crops in this area.In most of the soils applied sludge and the crops grow in it Cd/Zn is<1%. Pot experiments have shown that the applying of local sludge and sewage had more influence on the growth of rice than the applying of sludge and then clear water. Therefore when sludge containing heavy metals is applied, the amount of it should not exceed 5000 jin per mu. The experiment in fields and pots have also proved that the amount of heavy metals transferred to plants from soil and then sent out through plants was very small. However, more mercury, cadmium and arsenic are transported than lead and chrome.