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.
