Microplastic pollution in aquatic ecosystems: A comprehensive review of impacts on aquatic animals

Microplastics (MPs) pollution has emerged as a significant global issue, posing potential threats to diverse ecosystems and wildlife species. Scientists have been documenting the presence of plastics in aquatic environments since the 1950s. Annually, approximately 8 million tonnes of plastic waste make its way into the oceans, a consequence of the rapid increase in plastic production. This plastic debris originates from various sources, including packaging materials, utensils, cosmetics, and plastic used in fishing nets, as well as lost nets, cages, and waste from fishing vessels. The fragmentation of this debris, whether through physical processes or biological means (including the action of plastic-degrading bacteria), leads to the creation of smaller particles known as ‘microplastics’ (less than 5 mm), which include even tinier particles termed plastics (less than 150 µm). These ubiquitous particles can be ingested, either directly or indirectly, by aquatic organisms, thus entering complex food webs. When contaminated fish are consumed by humans, there is a trophic transfer of MPs, potentially resulting in adverse health effects. The issue of marine MPs debris exemplifies the challenge of balancing the convenience of plastic use in everyday life with the ecological damage caused by improper disposal. Marine wildlife – including sharks, rays, turtles, whales, fish, shrimp, and seabirds – is affected by MPs. While chronic exposure is rarely fatal, it can harm individual animals by impairing feeding and draining energy reserves, which in turn can affect reproduction and growth. This review explores the impact of MPs (bibliometrically and comprehensively) on aquatic wildlife.