In situ stabilization of arsenic and metal-contaminated agricultural soil using industrial by-products

The usefulness of limestone, red mud, and furnace slag on the in situ stabilization of arsenic (As) and heavy metals was evaluated relative to different endpoints (microorganisms, plants, and humans). Individually or combined treatment of iron-rich amendments were effectively lowered the availability of trace elements. Compared to control soil, Ca(NO3)2-eatractable As, Cd, Pb, and Zn was reduced by 58%, 98%, 98%, and 99%, respectively, by combined treatment of limestone and red mud. The decreased availability of trace elements was accompanied by increased microbial activity (respiration, glucose mineralization, and soil enzyme activity) and decreased plant uptake of trace elements. Compared to non amended control soil, only 13%, 28%, 47%, and 12% of the As, Cd, Pb, and Zn, respectively, detected in combined treatment of limestone and red mud. These results suggest that iron-rich industrial by-products could be used for remediation of soils co-contaminated with metals and arsenic.