Arsenic Contamination of Water Sources in Southern Africa: Role of Artisanal and Small Scale Mining Sector

Arsenic (As) is an element that occurs either as a component of many minerals, sulphur, and metals or as a pure element as a crystal. Elemental arsenic and arsenic compounds are toxic to the environment and threaten human health. Arsenic is mutagenic, carcinogenic, and teratogenic. It naturally exists as inorganic arsenic compounds, organic arsenic compounds, or arsenic gas. Inorganic arsenic is more toxic than organic arsenic compounds. This paper reviews the state of arsenic contamination in water sources in Southern Africa. Research in Africa has reported elevated levels of As in both surface and groundwater systems. The World Health Organization has set a standard of 10 µg/L. However, concentrations of arsenic of up to 1760 µg/L were reported in groundwater in South Africa, 188 µg/L reported in surface water in Botswana, 96 µg/L from Eastern Zimbabwe, and 119 µg/L in surface water from South Africa. Studies reported low levels of As in rivers from Mozambique compared to rivers in South Africa. However, studies have reported that only 13% of the groundwater in South Mozambique was suitable for drinking purposes. High As levels in surface water were generally linked to mining activities, agricultural activities through herbicides and pesticides, disposal, and incineration of municipal and industrial waste. Whereas high concentrations of As in groundwater are generally related to local geology, mineralization, and geothermal water. Furthermore, in Southern Africa, soil and groundwater contamination could be a result of the legacy effects of the application of inorganic arsenic-based compounds used for cattle dipping. It can be summarized that anthropogenic and geogenic sources are the major causes of elevated As levels, particularly in soils and water within the Southern Africa region. More efforts should be directed towards the removal of the metal from both surface and groundwater systems to curb the effects of arsenic toxicity.