Effects of humus on environmental mobility of mineral bound mercury

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.