Microplastic Pollution in Beach Sediments along the Badagry Coastline, Lagos State

Microplastic pollution has emerged as a critical global environmental concern, with coastal sediments serving as major sinks for these persistent contaminants. This study assessed the abundance, type, and spatial distribution of microplastics in beach sediments along the Badagry coastline, Lagos State, South West Nigeria. Sediment samples were collected from six transects spanning the high tide, mid-tide, and low tide zones during two sampling campaigns in 2024. Microplastics were extracted through density separation using sodium chloride solution and identified visually under a stereomicroscope. Particles were classified by shape, colour, and size category. Fourier transform infrared spectroscopy was applied on representative samples to confirm polymer composition. A total of 1,840 microplastic particles per kilogram dry weight were recorded across all stations, with fibres (52%) and fragments (28%) as the dominant morphotypes. Polyethylene, polypropylene, and polystyrene were the most frequently identified polymers. Microplastic density was highest at the high tide line, reflecting wave-driven accumulation. Proximity to urban discharge points and storm drains correlated strongly with elevated particle counts. Seasonal comparison indicated higher abundance during the post-dry season, linked to wind-driven beach deposition. The findings highlight the urgent need for integrated waste management strategies in Lagos coastal communities and call for regulatory enforcement of single-use plastic bans to curb marine plastic input. Keywords: microplastics, beach sediments, Badagry, polymer identification, coastal pollution.