A critical review of soil pollution sources and advances in the remediation of arsenic-contaminated soil

Arsenic (As) is a hazardous, non-essential semi-metal detrimental to animals, people, and plants. Its environmental levels have risen globally due to increased mining, industrial activities, vehicle emissions, and other human actions, posing significant environmental and health concerns. Hence, the remediation of As-contaminated soils requires urgent attention to ensure the provision of safe and healthy food for humans. This paper delineates the origins of soil As pollution, its environmental ramifications, the complex dynamics of As contamination, contemporary advancements in remediation methods, and suggestions for addressing soil As pollution. The discussion also encompassed success stories and the possibilities of various approaches for remediating As-contaminated soils. The discussion focused on several mechanisms, such as bioaccumulation, bio-sorption, electrostatic attraction and complexation, that mitigate the toxicity of As by transforming As (V) into As (III). Furthermore, it delineated the research gaps that require addressing in subsequent studies. Various techniques are employed globally to remediate As-contaminated soils, categorized into physical, chemical, biological, and other innovative strategies. Physical methods include soil washing and replacement, excavation, containment and encapsulation, vitrification, and soil blending. Chemical treatments include lime application, phosphate amendments, iron oxides and biochar, inorganic additives, and redox manipulation. Biological strategies encompass phytoremediation, bioremediation, microbial detoxification, microbial volatilization, and rhizoremediation. Lastly, other techniques incorporate innovative methods like phytovolatilization, phytostabilization, and electrokinetic remediation. Consequently, the present review will assist in formulating suitable and new techniques to mitigate As bioavailability and toxicity, as well as to sustainably manage As-contaminated soils, thereby diminishing the harmful impacts of As on the surrounding and human health.