稀土元素对土壤-植物系统中重金属行为的影响及其机理研究进展

Effects of Rare Earth Elements on Heavy Metal Behavior and Their Action Mechanisms in a Soil-plant System

随着稀土的持续开采和在各领域中的广泛应用,稀土进入土壤环境的风险逐渐增大,导致稀土与重金属的复合污染问题,其中稀土元素对土壤-植物系统中重金属行为的影响研究也开始受到关注。研究已表明,外源稀土可以显著影响土壤与植物系统中重金属的赋存形态和迁移分布特征,可缓解重金属对植物的毒性,也可能和重金属产生协同毒害作用。分别从浓度-剂量、作用时间、稀土或重金属元素种类、稀土元素的施用方式和施用时间以及植物品种等方面详细综述了稀土元素对土壤-植物系统中重金属行为影响的主要因素及其机理的研究进展。最后,对稀土影响土壤-植物系统中重金属行为的研究现状进行了总结并展望了其研究前景。

At present, with the continued exploitation of rare earth and its extensive application in various fields, the risk of rare earth elements entering soil environment is gradually increasing. Therefore, the combined pollution problem of rare earth elements and heavy metals in soil-plant system is becoming increasingly serious. However, the present researches mainly focus on the combined pollution of heavy metals and little is known about the effects of rare earth elements on the heavy metal behavior in the soil-plant system. Recently, studies about the effects of rare earth elements on heavy metals in soil-plant system are beginning to receive attention due to rare earth is widely used in different fields. The studies indicate that exogenous rare earth elements can significantly affect the chemical speciation and migration distribution characteristics of heavy metals in the soil-plant system. The concentrations of rare earth elements can significantly affect heavy metal toxicity. A low concentration of rare earth elements may inhibit heavy metal toxicity, whereas high concentrations may have synergistic toxic impacts and aggravate the adverse effects on the plant growth. Based on the existing researches, the main factors that affect the influence of behaviors of heavy metal in the soil-plant system caused by rare earth are discussed. These factors include the dosage and concentrations, stress time, element species, the application mode and time of rare earth elements, and plant species. In addition, the possible mechanisms are also analyzed. In the end, the summary and future research directions are suggested.