Soil Pollution by Arsenic in Sub-Saharan Africa

Abstract

In this chapter, the chemistry of arsenic (As) and the toxicity of the metalloid in soils of sub-Saharan Africa (SSA) region was studied. The pentavalent (arsenate) and trivalent (arsenite) forms of the metalloid were found to be the most common, with the latter being more mobile and toxic compared to the former. In soils, the mobility and toxicity of As was influenced by soil physicochemical characteristics such as the organic matter content, pH and redox potential as well as the dissolution and speciation capacity of the metalloid. Industrial activities such as production and use of electronics, agrochemicals, wood preservatives, ore mining and smelting, coal processing, production of cosmetics, alloy-making and disposal of their resultant wastes were associated with As contamination in soils. Evidently, As has the potential to contaminate soils in SSA region and transfer the toxicity to other resources and into trophic chains where it exerts negative effects.