长三角和珠三角土壤中汞的化学形态、转化和吸附特性

为了解长江三角洲和珠江三角洲农业土壤中汞的积累可能产生的环境影响,选择10个代表性农业土壤样品,研究了土壤中汞的化学形态、积累过程中形态的转化及吸附-解吸行为.研究表明,当无外源汞加入时,长江三角洲和珠江三角洲农业土壤中,汞主要以稳定的残余态形式存在.但随着汞加入量的增加,土壤中可交换态汞显著增加,增加程度与土壤性质有关.土壤pH是影响土壤汞有效性最重要的因素,其对土壤汞的吸附、解吸、形态转化和存在形态均有很大影响.土壤酸化可促进土壤汞的释放,加剧对环境的危害,防治土壤酸化也可有效降低土壤中汞对环境的危害.

Chemical forms, transformation and adsorption of mercury in the soils of the Changjiang Delta and Zhujiang Delta

This study aims to present the authors' analysis of the chemical forms, transformation and adsorption-desorption behavior of mercury (Hg) in ten kinds of agricultural soils collected from the Changjiang and Zhujiang Delta-areas. The results of our analysis show that Hg in normal or slightly contaminated agricultural soils was mainly presented in residual forms. However, exchangeable Hg fraction with high availability can increase significantly with the increase of Hg pollution in the soils. Besides, soil pH has a great influence on the Hg adsorption-desorption, transformation and chemical forms in the soils. Furthermore, it is also a most important factor to control the Hg availability in the soils. Soil acidification could increase the release of Hg from the soils, hence aggravating the risk of Hg to the surrounding environment. And in the end, the study has also suggested that preserving soil from acidification is also important for decreasing soil Hg environmental risk.