Microplastics are ubiquitous in the environment, with high concentrations being detected now also in river corridors and sediments globally. Whilst there has been increasing field evidence of microplastics accumulation in the guts and tissues of freshwater and marine aquatic species, the uptake mechanisms of microplastics into freshwater food webs, and the physical and geological controls on pathway-specific exposures to microplastics, are not well understood. This knowledge gap is hampering the assessment of exposure risks, and potential ecotoxicological and public health impacts from microplastics. This review provides a comprehensive synthesis of key research challenges in analysing the environmental fate and transport of microplastics in freshwater ecosystems, including the identification of hydrological, sedimentological and particle property controls on microplastic accumulation in aquatic ecosystems. This mechanistic analysis outlines the dominant pathways for exposure to microplastics in freshwater ecosystems and identifies potentially critical uptake mechanisms and entry pathways for microplastics and associated contaminants into aquatic food webs as well as their risk to accumulate and biomagnify. We identify seven key research challenges that, if overcome, will permit the advancement beyond current conceptual limitations and provide the mechanistic process understanding required to assess microplastic exposure, uptake, hazard, and overall risk to aquatic systems and humans, and provide key insights into the priority impact pathways in freshwater ecosystems to support environmental management decision making.
Bibliographical noteFunding Information:
This work was supported by the Birmingham Institute of Global Innovation and funded through the Leverhulme Trust research grants ( RPG-2017-377 and ECF-2019-309 ) and the EU H2020 ITN Grants HypoTrain ( H2020-MSCA-ITN-2014 - 641939 ) and HiFreq ( H2020-MSCA-RISE-2016 - 734317 ). Berta Bonnet was funded through the EU H2020 Marie Curie Individual Fellowship (NanoTOX - 706172 ) and Jen Drummond by the Royal Society International Newton Fellowship ( NIF∖R1∖180935 ).
© 2020 Elsevier Ltd
- Food web
- Water Pollutants, Chemical/analysis
- Environmental Monitoring
- Food Chain
- Fresh Water
ASJC Scopus subject areas
- Health, Toxicology and Mutagenesis