Transfer and transformation mechanism of chromium in stainless steel slag in pedosphere

The trivalent chromium (Cr) leached from stainless steel slag can be oxidized into hexavalent Cr with strong toxicity in the natural storage process, thus causing severe pollution to the surrounding soil, water, and atmosphere. Currently, the toxicity hazards caused by high Cr concentrations in plants, animals, and humans have attracted widespread attention from across the world. In this study, an overview is presented regarding the occurrence mode, leaching mechanism, and influencing factors for the presence of Cr in the soil of stainless steel slag under natural landfilling conditions. Meanwhile, a summary is made for the research progress in Cr absorption, transport, and accumulation in the soil-plant system. Besides, allowing for the toxicity and detrimental effect of Cr(VI) in the soil as well as the application of biological and chemical methods for the remediation of Cr(VI)-contaminated soil, a review is conducted on the approach to recycling Cr from stainless steel slag and the application of chemical remediation and biological methods to remedy Cr-containing soil. Finally, a discussion is conducted about the transfer and transformation behavior of Cr in soil-plant system, the practical application of soil remediation technology and the prospect of research in this field.