农田土壤重金属污染阻控技术研究进展

Research Progress on Speciation and Physiological Control of Heavy Metal in Soil-plant System

土壤重金属污染阻控技术主要是指通过化学行为将重金属钝化在土壤中,或利用植物生理作用,喷施各种阻隔剂抑制重金属在植物体内的流动,或通过水分管理、深耕等农艺措施调控重金属进入植物体内的行为。其中,钝化技术主要是向土壤中添加钝化剂,通过吸附、沉淀、络合、离子交换和氧化还原等一系列反应,降低重金属污染物的生物有效性和可迁移性,从而达到修复目的的方法;阻隔技术通常指通过向农作物喷施肥料以调节其生理代谢,从而降低农作物对重金属的吸收或降低重金属向作物可食用部位的转运。而作物从土壤中吸收重金属,不仅取决于土壤中重金属的含量,还受到土壤性质、肥料种类、作物种类、水分条件及耕作制度的影响,因此,合理改善上述条件,可有效抑制重金属活性,降低其生物有效性。土壤重金属污染阻控技术具有处理成本低廉、效果明显、操作简单和不影响农作物生产等优点,是土壤重金属污染治理的重要手段之一,是当前世界范围内的研究热点,亦是一种治理土壤重金属污染的环境友好技术。文章主要介绍和评述了土壤重金属污染阻控技术的原理、类型、技术优点及进展情况,并对今后的研究重点进行了简要的讨论。

Stabilization of heavy metals in soil can be accomplished by changing their fractions in soil, separating them in plant tissue such as vacuoles, or regulating of agronomy such as tillage, cultivation and moisture. On the one hand, addition of some kinds of deactivators in soil can change heavy metal from mobile and bioavailable forms to immobile forms;On the other hand, spraying of some kinds of foliar nutrients can stabilize heavy metal at non-edible parts of plants. Furthermore, absorption of heavy metal by crops from soil not only depends on heavy metal concentrations in soil, but also depends on the nature of soil, fertilization, varieties of crop, moisture regimes and farming systems. Therefore, reasonable improvement of above conditions can effectively inhibit the mobility and bio-availability of heavy metals. These technologies have the advantages of low costs, environmental friendliness, obvious positive effects and simple to operation. Moreover, crop output and quality would not be affected by these technologies, which are becoming a research hotspot in world scale. In the present paper, the mechanism, types, technical advantages and progress of soil heavy metal pollution control technologies are introduced and reviewed.