Chapter 9 - Cadmium Accumulation in Crops and the Increasing Risk of Dietary Cadmium Exposure: An Overview

Abstract

Soil contamination with toxic heavy metals, such as cadmium (Cd), lead (Pb), and mercury (Hg), has become one of the major global environmental problems since the year 2000. During these years, increased industrialization, along with anthropogenic activities and rapid change in agricultural practices, has significantly contributed to the enhanced accumulation of heavy-metal elements in the environment. Plants, being sessile in nature and with their obligatory dependence on sunlight for energy, are widely exposed to various environmental stress factors, including the heavy metals, and therefore, are constantly facing the tremendous task of maintaining the genome integrity for survival and adaptation under such stress conditions. Excess level of accumulation of heavy metals in soil frequently induces both cytotoxic and genotoxic effects and thus adversely affects plant growth and reproductive potential by imposing genome instability. Soil contaminated with heavy metals like Cd and Pb represent one of the important stress conditions for the plants. Cd is released into the environment mainly through some anthropogenic activities, such as use of phosphate fertilizers and regular disposal of industrial, municipal, and household wastes. These sources may cause enhanced accumulation of Cd in the soil and hence in crop plants. Eventually, this may increase the dietary Cd exposure. This situation has created a problem of major concern worldwide, as Cd is particularly a potentially harmful pollutant because of its ability to induce high cellular toxicity. This review mainly provides insights into the cytotoxic effects of Cd in plants and the increasing human risk for developing various diseases due to the problem of enhanced accumulation of this harmful heavy metal in the food chain and dietary sources.