Influence of amendments and aided phytostabilization on metal availability and mobility in Pb/Zn mine tailings

摘要

A greenhouse experiment was conducted to evaluate the effect of four different amendments, bone mill, bottom ash, furnace slag, and red mud, as immobilizing agents and the plant species Miscanthus sinensis and Pteridium aquilinum in aided phytostabilization of Pb/Zn mine tailings. The effects of amendments and plants on the availability and mobility of heavy metals were evaluated using single extraction, sequential extraction, pore-water analysis, and determination of heavy metal concentrations in plants. The application of Fe-rich amendments significantly reduced the amount of soluble and extractable heavy metals in the tailings (p < 0.05). Furnace slag and M. sinensis reduced CaCl_2-extractable heavy metals by 56-91%, red mud and P. aquilinum treatment was the most effective at decreasing bioaccessible Pb, reducing it to 34% of the total Pb. Compared to control, water soluble Cd, Cu, Pb, and Zn were reduced by 99,99, 98, and 99%, respectively, in the red mud and P. aquilinum tailings. M. sinensis accumulated heavy metals mainly in the root, and had lower translocation factors compared with P. aquilinum. The results of this study suggest that M. sinensis can be used in aided phytostabilization for these types of mine tailings and Fe-rich amendments are effective for the in situ immobilization of metals.