Soil contaminants: sources, effects and approaches for remediation

The contamination of soils with various inorganic and organic contaminants led to the degradation of large expenses of urban and arable lands throughout the world. The presence of toxic contaminants poses a significant health risk to humans and other ecological systems. Scattered literature is harnessed to critically review the various natural and anthropogenic sources and potential hazards and to identify the best possible remediation strategies for a number of contaminants, mainly those inorganic in nature such as arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), and zinc (Zn) commonly found in the contaminated soils. The remediation methods including chemical and phytoremediation techniques are discussed in this chapter. Chemical remediation methods such as immobilization, soil washing, and vitrification are relatively expansive and hazardous to the environment, and are not suitable for large-scale soil remediation activities. Conversely, phytoremediation has emerged as an environmentally friendly and feasible technology for restoration of contaminated soils, but very limited efforts have been directed to demonstrate this technology under field conditions. Remediation of heavy metal-contaminated soils is necessary to reduce the associated risks, make the land resource available for agricultural production, enhance food security, and scale down land tenure problems arising from changes in the land-use pattern.