Microplastic Contamination in Commercial Fish Species from Lekki Lagoon, Lagos

Microplastic contamination of aquatic food webs has emerged as a critical food safety and ecological concern globally, with growing evidence of ingestion by commercially important fish species. This study investigates the occurrence, abundance, and characterisation of microplastics in the gastrointestinal tracts of three commercially important fish species landed at the Lekki Lagoon fish market, Lagos State, South West Nigeria. A total of 120 specimens comprising Tilapia zillii, Chrysichthys nigrodigitatus, and Ethmalosa fimbriata are purchased from artisanal fishers between January and June 2024. Fish are dissected under laboratory conditions, and gastrointestinal contents are extracted, digested with potassium hydroxide solution, and filtered for microplastic isolation. Microplastics are visually identified using stereomicroscopy and characterised by morphology (fibres, fragments, films, beads), colour, and size. Selected particles undergo polymer identification using Fourier-transform infrared spectroscopy. Abundance is expressed as the number of particles per individual and per gram of tissue. Preliminary findings are expected to show the highest microplastic loads in Tilapia zillii, a benthic species with broad feeding habits. Fibres derived from fishing gear and textile washing are anticipated to dominate the microplastic morphotype inventory. Findings raise significant implications for consumer health and food safety regulation, and the study recommends mandatory microplastic monitoring in fisheries quality control frameworks. Keywords: microplastics, fish contamination, Lekki Lagoon, food safety, Lagos fisheries