Microfibre effects on the freshwater amphipod Gammarus pulex

Microplastic pollution is an emerging global issue of growing concern in environmental research. A substantial area of microplastic pollution is the release of polymer microfibres associated with clothing and fabrics through wastewater. Generally, research has focussed on the sources and fate of microplastics and less research has been undertaken on the effects caused in various aquatic species. This study set out to address some of the literature gaps highlighted and investigated the effects microfibres could have on a keystone freshwater species, Gammarus pulex. Ecotoxicity tests were carried out to assess the impact of microfibres on mortality, locomotion, ingestion, feeding and growth of individuals. These tests were carried out at high and low concentrations to observe short- term effects that microfibres had on individuals. Significant mortality and reduction in locomotion was observed in the majority of Ecotoxicity tests even at low concentrations. All individuals were found to have readily ingested microfibres throughout the study which caused increased mortality and a reduction in locomotion. All microfibre types caused mortality and reduced locomotion, even natural cotton microfibres. The study highlighted the negative impacts of microfibres on aquatic species especially when considering that microplastic pollution is growing and accumulating in aquatic environments. Further research in establishing current and future microplastic concentrations is required to further standardise ecotoxicity tests and allow more accurate testing at environmentally realistic conditions.