Inorganic Amendments for the Remediation of Cadmium-Contaminated Soils

Abstract Cadmium (Cd) toxicity is one of the most devastating threats in the agricultural field. It is an alarming risk for human health and environment sustainability, being highly mobile and ecotoxic even at low concentration. Escalated industrialization and intensive agricultural practices have liberated large amounts of Cd into agricultural lands. However, the use of inorganic amendments for Cd immobilization and/or insolubilization is a benign, realistic, and economically feasible approach. Various inorganic amendments, depending upon their composition, play an important role for Cd decontamination by accelerating the precipitation, ion exchange, and immobilization processes. Latest research shows that use of Cd immobilizers binds Cd into the soil medium by surface adsorption, chelation, and precipitation, and is important for safe food production from low- to medium-Cd-contaminated soil. However, researchers are ambiguous about the stability and persistence of these complexes, precipitates, and chelates in the soil environment. Similarly, use of Cd mobilizers such as sulfur and ammonium reduce the soil pH and, thus, accelerates Cd availability to hyperaccumulators. Hyperaccumulators collect the bulk of Cd concentration into their various tissues that can be used for oil formation and is an efficient strategy for Cd decontamination. Besides, use of nutrient-based amendments such as phosphate and silicon-based fertilizers are attracting more concern of farmers, due to the high-fertility status of soil along with remediation purposes. Given the previously described sanctions, economically feasibility of inorganic amendments is well documented for Cd decontamination in agricultural soils. This chapter covers all aspects of Cd contamination of soils and its negative impacts on plant growth and human health. Moreover, this chapter also explains the use of inorganic amendments, their mechanism, and efficacy for Cd decontamination.