Potential of natural coagulants for bioremediation of persistent organic pollutants in wastewater in sub-Saharan Africa: A review

Abstract

Sub-Saharan Africa (SSA) is a significant user of pesticides, relying on agriculture for economic development. Pesticides and agrochemicals contribute to the presence of Persistent Organic Pollutants (POPs) in the environment. This review addresses knowledge gaps in monitoring and quantification of POPs, the application of natural coagulants for bioremediation, and associated environmental and health risks in SSA. Findings reveal inconsistencies in monitoring methods and analytes, hindering the identification of temporal trends. Legacy POPs show decreasing concentrations in soil/sediment and aquatic organisms, while some POPs increase in water, fish, fruits, and vegetables. Some river systems exceed acceptable ranges for PCBs according to USEPA standards. PFASs, particularly PFOA and PFOS, are prevalent. Natural coagulants, like Moringa oleifera and chitosan, are gaining popularity for water treatment due to their environmental sustainability and effectiveness in POP remediation. Trivalent cations in natural coagulants show promise for POP bioremediation. However, challenges remain in scaling up natural coagulant applications for commercial water treatment. This review highlights the need for standardized monitoring procedures and emphasizes the potential of natural coagulants in POP remediation efforts.