腐殖酸对矿物结合汞环境迁移性的影响及其机制研究

Effects of humus on environmental mobility of mineral bound mercury

腐殖酸对矿物结合汞环境迁移活性 (挥发性 ,植物迁移活性及水迁移活性 )兼具抑制与活化的双重效应。富里酸对铁锰氧化物结合汞无论是挥发活性还是植物迁移活性及水迁移活性均表现极显著的促进效应 ,而酸性淋溶将加速富里酸对硅酸盐粘土矿物结合汞的环境迁移的活化进程 ;灰色胡敏酸对矿物结合汞的活化效应较弱 ,并更易于对矿物汞环境活性表现抑制作用。棕色胡敏酸性质与影响介于富里酸与灰色胡敏酸之间。腐殖酸作用下 ,矿物结合汞的环境迁移形态发生了改变 :元素态汞、游离的有机结合态汞和溶解态无机汞依次成为其发生大气环境迁移、土壤垂直水迁移和植物迁移最有效的形态。

Humus including fulvic acid, brown humic acid and grey humic acid had either suppressing or activating effects on the environmental mobility such as atmospheric volatilization, soil vertical transport and plant uptake of five types of mineral bound Hg(Fe_2O_3-Hg, MnO_2-Hg, CaCO_3-Hg,kaolinite-Hg and bentonite-Hg). Fulvic acid could dramatically promote the environmental mobility of Fe_2O_3-Hg and MnO_2-Hg, while acid leaching could accelerate such activating processes of fulvic acid acted on silicate mineral bound Hg . The activating effects of grey humic acid on the mineral bound Hg was the modest , furthermore, it was prone to suppress or retard the environmental mobilization of mineral bound Hg. The effect of brown humic acid was moderate. Under the influence of the humus, the environmental transferring forms of the mineral bound Hg were changed: Elemental Hg 、mobile humus bound Hg and soluble inorganic Hg became the most environmental mobile forms for mineral bound Hg in atmospheric volatilization, soil vertical transport and plant uptake respectively.