Cadmium Contamination: Sources, Behavior, and Environmental Implications

Cadmium (Cd) is a well-recognized carcinogen, which poses significant environmental and health concerns due to its toxic nature and persistence in the environment. It is an inescapable component of our food chain as it is a naturally occurring Earth element. Natural activities like weathering of rocks and minerals, volcanic eruptions, and forest fires contribute to the global Cd load, whereas multipurpose uses and anthropogenic activities have increased this load and exposure manifolds. Once released into the environment, Cd can persist in the soil for an extended period due to its long half-life and global cycling. Cadmium can be present in different forms and fractions in the soil. The toxicity of Cd depends on the speciation and available fractions, not the total concentration. This chapter further explores the speciation and biogeochemical behavior of Cd in soil. Cadmium is extremely mobile in soil systems. The mechanisms of Cd mobilization and factors influencing its mobility are also discussed in detail. Furthermore, this chapter discusses the uptake and translocation of Cd by plants, the toxic effects of Cd on soil microbes and plants, and the biomagnification of Cd in food chains leading to human exposure and health risks.