Arsenic and its management in soil

Abstract

Arsenic (As) is a toxic metalloid and carcinogenic element that occurs widely in environment around the world. Arsenic is introduced into soil and water through geological (weathering of rocks and minerals) and anthropogenic pathways (mining, pesticides, fertilizers, timber treatment etc). Irrigation of agricultural land with As-contaminated groundwater or wastewater, particularly in India, Bangladesh and South-East Asia resulted in the accumulation of arsenic in both soils and plants posing risks to soil ecosystems and human health. Arsenic in soil and water exists in a different valence state, but predominantly as toxic As(III) and less toxic As(V) form. Arsenic toxicity is one of the most challenging problems in drinking water, as well as food crops (Samal et al., 2021). With greater public awareness of arsenic poisoning in animals and human nutrition, there has been growing interest in remediation technologies for mitigating As-contaminated ecosystems. Remediation of As-contaminated soil improves physical, chemical and biological approaches that may achieve either partial/complete removal of arsenic from soil and water. Many technologies like bioremediation, phytoremediation, soil mixing, soil washing, soil capping, filtration, adsorption and immobilization are used for arsenic removal from soil and water. Phytoremediation is a bioremediation process that uses various types of plants to remove, transfer, stabilize, and/or destroy contaminants in the soil and groundwater. But most of the arsenic still remains in the environment and there is always a risk of leaching caused by changes in the environmental conditions. Integrated approach involving a combination of physical, chemical and biological technologies is needed for the successful and effective management of As-contaminated environment.