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Abstract The technology of in situ immobilization with amendments is an important measure that remediates the soil contaminated by heavy metals, and selecting economical and effective amendments is the key. The effects and mechanism of steel slag, the silicon-rich alkaline by-product which can remediate acidic soil contaminated by heavy metal, are mainly introduced in this paper to provide theory reference for future research. Firstly, the paper analyzes current research situation of in situ immobilization with amendments. Then, it introduces the main physicochemical properties of steel slag, and the effect on soil pH value as well as heavy metal activity. Besides, the paper elaborates the promoting effect on silicon-requiring plant and the strengthening mechanism for its resistant capability of heavy metal. According to the analysis, the application of steel slag could be a potential valuable strategy to remediate acidic soil contaminated by heavy metal by modifying the transformation of heavy metals in both soil and plant , so that the translocation of heavy metal in food chain is reduced.
Key words Steel slag, Soil, Heavy metal, Acidic, Remediation
The development of mineral resources has promoted our social development. However, mining and metal melting activity have also greatly contaminated die mineral areas and farmland nearby with die acid mining drainage. Mineral layers with coal , steel and nonferrous metal mosdy have varies types of metal sulphides inside. In the process of mining, tailing pond and spoil heap produced have made metal sulphides diat originally in reducing state expose to air, dien producing sulphuric acid by oxidation and releasing heavy metal. The pollutants constandy dissolve in rain, or wastewater brought by mining, ore dressing, smelting would form acid mine drainage ( AMD , pH < 5 ) . These pollutants keep flowing towards downstream , which will result in heavy ecological degradation of mineral areas . Two problems are brought about: on one hand, die extreme pH2 strongly affects the enzyme stability and different metabolic activity inside crops; on the other hand, the heavy metal amount is excessive, acidic environment further aggravates the heavy metal release , dius leading to great poison to plants . Mining and metal smelting have become one of the vital sources of heavy metal contamination to farmland . What is worse...