Sources, Indicators, and Assessment of Soil Contamination by Potentially Toxic Metals

Abstract

Soil pollution caused by potentially toxic metals has become a worldwide environmental issue. Geogenic processes and anthropogenic activities are two important sources of soil pollution. Soils may inherit toxic metals from parent materials; however, soil pollution mostly results from industrial and agricultural activities. Contamination by metals can be indicated by the changes in chemical, biochemical, and microbial properties of soils and plant responses. The total concentration of toxic metals in soil is still the most widely used indicator for risk assessment although extractable amounts have been reported to be more closely related to plant uptake. Several models have been proposed for assessing soil contamination by toxic metals, but none of them are commonly accepted for application to a wide range of soils. This review paper highlights how toxic metal contamination negatively affects soil and environmental quality, impacts food quality and security, and poses a threat to human health. Further research is needed to not only improve soil contamination diagnosis, modeling, and regulatory standards but also for remediation efficiency.