Evidence Reviews on Analysis, Prevalence & Impact of Microplastics in Freshwater and Estuarine Environments Evidence Review 3 What is/are the impact(s) of microplastics on freshwater and estuarine biota?

Abstract

This Rapid Evidence Assessment used the systematic review procedure to assess the current evidence available on the impact of microplastics on freshwater and estuarine biota. It is important to understand what consequences microplastics may cause in the environment. Furthermore, we need to understand which types of microplastics cause impacts and at what concentrations. A review was conducted of the primary literature, including grey literature, which reported evidence of the impact of microplastics on freshwater and estuarine biota. A particular focus were those publications which reported evidence on the extent to which microplastics influence the behaviour, feeding, growth, reproduction and survival of freshwater and estuarine biota, and any thresholds at which impacts occurred. Publications released prior to April 2019 were included in this review. Evidence was acquired according to a predefined set of questions, compiled into a database containing full details of the source and its relevance to the project questions, and the evidence analysed, taking into account reporting biases in the literature, to produce a digestible summary of the evidence base available to answer the main project question and sub-questions, namely, What is/are the impact(s) of microplastics on freshwater and estuarine biota? a) To what extent do microplastics influence the feeding, growth, reproduction and survival of freshwater and estuarine biota? Do we know trigger levels or threshold values for microplastic impacts on biota? b) Are any differences between different taxonomic groups observed? c) Are results from laboratory studies relevant to microplastics at environmentally relevant field concentrations? d) Are any adverse impacts attributable to the particles or to adsorbed chemicals/microbes on the particles? e) Is there evidence to suggest impacts on populations of aquatic organisms?