Toxicity of Rhizospheric Cadmium-Contaminated Soil and Its Remediation

Cadmium (Cd) is a ubiquitous toxic metal that threatens all forms of life on Earth. After being released from different sources into the soil, Cd undergoes substantial transformation in the rhizospheric zone of the soil. This chapter thoroughly investigated all possible interactions of Cd with plant roots and microbes in the rhizosphere. When microbes and plants are exposed to Cd, it adversely affects growth and development, generates oxidative stress, and alters many physiological and metabolic processes in both microbes and plants. Both microbes and plants themselves use some internal adaptive mechanisms that allow them to lessen the negative effects of Cd exposure. In addition, the phytotoxicity of Cd can be minimized by applying some physical, chemical, and biological remediation strategies. This chapter explores all available Cd remediation strategies. Biological methods are considered the most effective ones in terms of availability, cost-effectiveness, and efficiency. Biological methods include phytoremediation, the use of microbes like mycorrhiza, and plant growth-promoting rhizobacteria. However, success stories of the field application of Cd remediation are minimal, and the mechanisms involved in the remediation processes are not fully understood yet. Further research is necessary to unveil the complete story of Cd phytotoxicity and its remediation. In essence, this chapter will provide a complete overview of Cd toxicity in microbes and plants, adaptive features, and all possible remediation strategies for the reader.