A comprehensive investigation of microplastic pollution prevalence and effects: A meta-analysis of global sediment and animal exposure research

Abstract

This meta-analysis examines the occurrence and impacts of microplastic pollution in aquatic ecosystems, emphasising sediment extraction techniques and their influence on benthic and pelagic organisms. Four unique measures for measuring microplastic content were discovered in 196 research, with microplastics per kilogram of sediment (MP/kg) being the most prevalent and trustworthy unit for trend analysis. The analysis indicates a biased distribution of microplastic concentrations, with certain studies documenting levels reaching 40,000 MP/kg, especially in coastal and deep-sea ecosystems, whereas freshwater systems are inadequately represented despite their considerable role in marine pollution. Research on benthic species indicated that elevated concentrations often led to detrimental consequences, including stunted development, cellular damage, and death; however, some species, such as the lugworm (Arenicola marina), demonstrated resistance. The Norway lobster (Nephrops norvegicus) exhibited sensitivity to ecologically relevant microplastic concentrations, highlighting possible economic repercussions for fisheries. Conversely, pelagic species, such as water fleas (Daphnia magna) and fish, had detrimental consequences, including decreased feeding and reproductive success at increased microplastic concentrations, although the effects differed by species. The results underscore a substantial knowledge deficit in freshwater species research and the need for studies that accurately represent actual environmental circumstances. The study concludes with recommendations for future research, highlighting the necessity of employing uniform units of measurement (MP/L for water, MP/kg for sediment), integrating ecologically pertinent microplastic concentrations, and accounting for the physical and chemical characteristics of microplastics in exposure experiments. The results emphasise the need for regulated, hypothesis-driven research to guide ecological risk evaluations and management approaches in a world increasingly impacted by plastic pollution.