Water and sediment microplastic dynamics in African inland freshwater systems: a review

Owing to its exceptional properties and versatility, plastic is one of the most widely manufactured and utilised materials globally. Its extensive use, coupled with inadequate plastic waste management, has harmed ecosystems and poses significant risks to human health. When plastic degrades in the environment, it breaks down into microplastics. These tiny particles are a growing global issue due to their widespread presence in aquatic environments. This review summarises existing information on microplastic contamination in water and sediment samples from African freshwater systems based on 41 published studies from eight countries. The data reveal extensive microplastic contamination in rivers, lakes, and reservoirs across the African continent, with polyethylene, polypropylene, and polystyrene being the most common polymers. Microplastics were more commonly detected in sediments than in water. Most microplastics were found during the rainy season, underscoring the need to intensify plastic waste recycling efforts prior to the onset of the rainy season. Fibres and fragments were the most frequently identified types of microplastics, with their distribution strongly influenced by seasonal variations, human activities, and proximity to urban centres. As microplastic contamination increases, more research is needed to better understand how its potential impacts on inland waters can be mitigated.