Occurrence and behaviour of emerging organic contaminants in aquatic systems

Public and research interest in emerging organic contaminants (EOCs) has been increasing in Africa and elsewhere due to their potential health risks. The objectives of the current chapter are: (1) to highlight the various classes and origins of emerging organic contaminants in aquatic environments, (2) to discuss the fate and behaviour of EOCs in aquatic systems including removal processes, and (3) to highlight research needs and constraints in Africa. EOCs detected include surfactants, pharmaceuticals and personal care products, plasticizers and solvents, flame retardants, and endocrine disrupting compound. Hotspot sources included crop and animal health and production systems, human health and vector control, industrial processes, and human hygiene, personal care and sanitation, and wastewaters. EOCs are released via industrial solid waste, industrial wastewaters/effluents, and as post-consumer wastes. Wind and water-driven processes control the dissemination of emerging contaminants from reservoirs into aquatic systems. The removal of EOCs can be achieved via: (1) adsorption using various materials (e.g. biochars, activated carbon); (2) biological processes using pure and mixed cultures, and activated sludge processes; (3) advanced oxidation processes; and (4) a combination of biological, chemical, and physical methods, including a series of various treatment processes. However, conventional and low-cost wastewater and drinking water treatment processes commonly used in most African countries, have low capacity to remove EOCs. Advanced techniques such as membrane technology and advanced oxidation are expensive for most African countries. Future research is required to address several knowledge gaps, but severe lack of research infrastructure and funding constrain research.