Plastic contamination in the Nigerian ecosystem: microplastic research, characterization techniques and regulatory gaps

Abstract

Microplastics (MPs) are pollutants within Nigerian ecosystems. They originate from both industrial manufacturing processes and weathering of plastic waste. This review evaluates the state of microplastic research in Nigeria, localized environmental concentrations, extraction and detection methodologies and existing regulatory frameworks. The main techniques used for MP extraction is wet peroxide oxidation, density separation followed by vacuum filtration, then Nile Red staining for visualisation; whilst detection and quantification are performed with Fourier Transform Infrared (FTIR) Spectroscopy, scanning electron microscopy (SEM) and gas chromatography with flame ionization detection (GC-FID). Other techniques which are available but not currently available in Nigeria include Raman Spectroscopy (RS) and pyrolysis gas chromatography-mass spectrometry (pyr-GC-MS). FTIR, SEM and RS are non-destructive, while pyr-GC-MS is a destructive technique. Densely populated cities like Lagos, Kano, and Ibadan experience high abundance of waste from domestic activities. Information from urban areas like the Kaduna Metropolis reveals heavy contamination across vital sites such as river networks, commercial sachet water, bottled water and dietary staples. It was observed that researchers face limitations, namely a lack of standardized protocols and access to advanced instrumentation such as Raman spectroscopy. An integrated framework connecting advanced analytical instruments with standard optimized sampling and processing protocols with enforceable waste management policies can mitigate the ecological and public health threats posed by plastic pollution in Nigeria.