Systematic Review of Arsenic Contamination, Toxicity and Remediation Techniques in Malawi

Arsenic (As) is one of the toxic contaminants in food and water. Excessive and long-term exposure to As causes harmful effects on humans, like arsenicosis, which manifests in disfiguring, disabling, and fatal diseases like cancer. People are mainly exposed to As through water and food intake, with a high exposure risk in developing countries like Malawi. The high prevalence of As exposure in many countries has led to studies to evaluate the As prevalence rate of exposure, toxic effects and consequences, and remediation measures and techniques. This review discusses an overview of the prevalence studies of As in foodstuffs and water, as well as their toxic effects and remediation measures employed to deal with the problem in Malawi. Although there are many studies conducted elsewhere about the presence of As in foodstuffs and water, there was only one (1) study on the presence of As in foodstuffs (0.040 mg/kg DW; inorganic arsenic) and one (1) study on herbal preparations (<0.045, undetectable). There were ten (10) studies on water (undetectable—0.5 mg/l; 0.4–14.5 lg/L) covering groundwater (7) (shallow wells, 3; boreholes, 4; hand-dug wells, 1 and households, 1), and surface water (3) (river, 1; lake, 2). Compared to the 10 parts per billion Environmental Protection Agency (EPA) limit for As contamination in water and 0.5–2 parts per million in food, the estimated amounts ranged from safe to toxic limits in water and safe in foodstuffs. However, the number of studies was too small to determine the arsenic prevalence in food and water, and the coverage of the studies was skewed towards one region. There were no studies on toxic effects, remediation measures, and techniques. Therefore, more studies are needed in Malawi to determine the prevalence of As exposure in all media, its toxic effects and remediation measures.