Evaluation of stabilizing materials for immobilization of toxic heavy metals in contaminated agricultural soils in China

Abstract

Contamination of agricultural crops by toxic heavy metals (HMs) causes serious damage to the human body. In this study, soil stabilization method was selected and coal mine drainage sludge (CMDS), waste cow bones (WCB), and steel making slag (SMS) were used as stabilization materials (SM). According to laboratory results, the optimum mixing ratio of SM and contaminated soil was 7 wt%. The optimal stabilizers for the stabilization of HMs contaminated soils were CMDS/SMS and CMDS/WCB, and the mixing ratio was 50:50 wt%. In addition, stabilization substances CMDS/SMS = 50/50, CMDS/WCB = 50/50, SMS/WCB = 50/50 and CMDS/SMS/WCB = 5/65/30 wt % were injected into four sites for 150 days. Results after 4 days of stabilization, SM of all compositions could satisfy the stabilization criteria. This study shows that CMDS, SMS, WCB, and a mixed composition of these can be effectively used as SM for agricultural soil contaminated with HMs. (C) 2018 Elsevier Ltd. All rights reserved.