Assessment of Microplastic Contamination in Surface Water Bodies and Its Public Health Implications in Ibadan, Oyo State

Microplastic contamination of freshwater systems is an emerging environmental and public health concern, yet the extent of contamination in Nigerian water bodies has rarely been empirically characterized. This study assessed microplastic contamination in three major surface water bodies in Ibadan, Oyo State, South West Nigeria, and evaluated potential public health pathways of human exposure. Water samples were collected from forty-eight sites across the Ona River, Kudeti River, and Ogbere River using standardized stainless steel sieves. Microplastic particles were characterized by size, shape, color, and polymer composition using stereomicroscopy and Fourier Transform Infrared Spectroscopy. Dietary exposure assessment was conducted by sampling freshwater fish, snails, and drinking water from wells adjacent to the sampled rivers. Results showed that mean microplastic concentration across all sampled water bodies was 182 particles per litre, with the highest densities recorded in sites receiving urban runoff and solid waste leachate. Polyethylene terephthalate, polypropylene, and polystyrene were the dominant polymer types identified. Fish muscle tissue samples contained microplastic particles in sixty-three percent of specimens. Drinking water from wells within 100 metres of the river banks showed detectable microplastic levels. The study represents one of the first empirical characterizations of freshwater microplastic contamination in Southwest Nigeria and establishes baseline data for future monitoring. Recommendations include targeted reduction of plastic waste inputs to water bodies and establishment of a national freshwater microplastic monitoring framework. Keywords: microplastics, freshwater contamination, Ibadan, public health, polymer characterization.