Assessment of Microplastic Pollution in Freshwater Systems of Adamawa State

This study assesses the presence and spatial distribution of microplastic particles in the Benue River and its tributaries within Adamawa State, North East Nigeria. Freshwater microplastic pollution is a growing global environmental concern, and its characterisation in Nigerian river systems beyond the Niger Delta remains very limited, particularly in North East Nigeria where baseline data are almost entirely absent. Water samples were collected from fifteen stations along a 90-kilometre stretch of the upper Benue River and three tributary streams in Yola North, Girei, and Demsa Local Government Areas using a 100-micrometre mesh plankton net towed at the surface for fifteen minutes per station. Microplastic particles were extracted, counted, and categorised by morphological type (fibre, fragment, film, or pellet) and size class. A subsample of particles from each site was subjected to Fourier transform infrared spectroscopy for polymer type identification. Results reveal microplastic presence at all fifteen stations, with particle abundances ranging from 0.8 to 12.4 particles per cubic metre of water. Fibres are the dominant morphological type at 63 percent, consistent with textile washing as a primary source pathway. Polyethylene and polypropylene are the most frequently identified polymers. Particle counts are highest at stations immediately downstream of Yola urban areas, declining progressively away from the urban zone. Seasonal comparison is limited in this study but preliminary dry season data suggest higher concentrations during low-flow conditions. The study provides the first quantitative microplastic dataset for Adamawa State freshwater systems. Recommendations include a systematic Benue River basin microplastic monitoring programme. Keywords: microplastics, freshwater pollution, Benue River, Adamawa State, plastic contamination.