Microplastic pollution: exploring trophic transfer pathways and ecological impacts

In the last century, human activities were the primary cause of air, water, and soil contamination. However, in the twenty-first century, while pollutants like sulfur oxides (SOx) and nitrogen oxides (NOx) remain significant, microplastics (MPs) have emerged as a new global environmental concern. Microplastics are plastic fragments that are less than 5 mm in diameter. Their widespread distribution in aquatic and terrestrial ecosystems has adverse impacts on various ecological systems. The presence of MPs has been well documented in diverse matrices, such as table salt, drinking water, indoor and outdoor air, beer, cold drinks, aquatic organisms, plants, and earthworms. The potential adverse effects of MPs consumption have been reported in various organisms, including earthworms and aquatic fishes; however, their potential effects on human health through respiratory, dietary, and other exposures are still being elucidated. This review provides a comprehensive overview of the current knowledge on potential sources, quantities present in water, table salt, air, and possible routes in the human body through different trophic levels. Furthermore, this paper reviews insights into the movement and accumulation of MPs at different trophic levels (i.e., aquatic, and terrestrial organisms) and their impacts on the cycling of soil carbon and nutrients (nitrogen and phosphorus). Additionally, this review paper addresses the current trends in MPs research and proposes strategic management techniques to mitigate MPs pollution.