Plastic pollution in the environment in Nigeria: A rapid systematic review of the sources, distribution, research gaps and policy needs

Plastic are emerging pollutants requiring urgent intervention for its management. In African countries like Nigeria, the evidence to inform plastic pollution management is scanty. This rapid review aimed to systematically evaluate evidence on the distribution, sources, biological effects, research gaps and policy needs of plastic pollution in various environmental matrices in Nigeria. Peer-reviewed journal articles on nano-, micro-, meso- and macroplastics contamination of water, sediment, air, soil and biota were accessed from PubMed, Google Scholar and Science Direct. They were screened, comprehensively revised and critically appraised for inclusion, data extraction and evidence synthesis. A total of 358,974 articles were accessed from any publication date up till May 30, 2021. Only 34 articles met the inclusion criteria and critical appraisal. Only 26 of the included studies reported the distribution, levels and/or effects of microplastics (MPs) (n = 12), macroplastics (n = 12) or both (n = 2) in water, sediment, biota, food and/or land. Only 15 of the 36 states and the Federal Capital Territory had any data on micro- and/or macroplastics. Macroplastics from land-based sources were mainly reported from educational institutions, residential areas and markets. Plastic sources reported were tire wear, cigarette butts, fishing ropes and gears, plastic bags, water sachets and e-wastes. Biological effects (oxidative stress, neurotoxicity, reduced plant root biomass) of virgin MPs were reported in crab, African catfish and lime tree only in laboratory experiments. Microplastic data in biota were limited to selected fish species, aquatic insects and gastropods. Only one (1) study on plastics in waterbodies in Northern Nigeria (Kogi State) was found. Research gaps on plastic distribution in terrestrial biota, other aquatic biota, soil, air, ground and potable water sources as well as biological effects were identified. Policy needs for plastic pollution management identified include stakeholder education, polymer replacement, recycling, tax and incentives to support the sustainability of life below water and on land (UN SDGs 14 and 15).