Impacts of MicroPlastics (IMP) in the Irish Freshwater Environment

banner image for research project "Impacts of MicroPlastics in the Irish Freshwater Environment"

This project is funded under the EPA Research Programme 2014-2020

Project Summary


The central objective of this project is to explore the impacts of microplastics on Irish fresh water aquatic organisms and ecosystems. This knowledge can inform monitoring programmes and regulatory policy by identifying those microplastics that pose the biggest risks to the freshwater environment.

Microplastics are plastic particles smaller than 5mm. These particles are widespread in seas and oceans, and their harmful effects on many different marine animals are well known. In contrast, we know relatively little about microplastics in fresh water: its sources, environmental fate, and biological impacts. Several large scale projects are currently working to develop monitoring technology for these plastic particles, as well as creating models to explain its spread and build-up for the marine environment. However, microplastics can vary greatly in chemical composition, size, shape and concentration, and may have different toxic effects under fresh water conditions. Therefore, more information is needed to identify those microplastics posing the biggest risk for fresh water species and the freshwater environment.

Microplastics in the environment

Microplastics are either resulting from fragmentation of larger plastic objects, or specifically produced as small plastic microparticles for use in products such as cleaning agents, cosmetics, or textiles. It is estimated that the island of Ireland emits some 5700 kg microplastics per year. Fibres released when washing clothes could produce even more microplastics again. Microplastics end up in the fresh water environment, either via a sewage/waste treatment plant, or directly (e.g. road run-off).

Once in the environment, microplastics are extremely persistent, although we need to know more about their fate in the fresh water environment.

Uptake of microplastics

Microplastics enter the food chain when they are consumed by small marine filter feeders (e.g. mussels, krill), or grazers (e.g. snails), or taken up by plants. These in turn are eaten by larger organisms, leading to a build-up of microplastic levels. High concentrations of microplastic have been found in organisms like fish, whales, turtles and birds. Little is known about small plastic particles in the fresh water food chain. This is an important issue, since evidence is emerging that plastic particles are present in food, although neither the source nor the impact on human consumers is well studied.

Microplastic impacts

Microplastics consist of a mixture of particles with diverse characteristics (size, charge, shape, chemical composition). They can affect consumers physically (e.g. causing obstructions) or chemically (causing changes in e.g. behaviour, growth rates and feeding). Effects of microplastics on marine organisms are well documented, but there is limited knowledge of their effects on plants and/or fresh water organisms.


Regulation of production and emission of microplastics will be a key component of any strategy that aims to reduce environmental pollution by plastics. In this project we will quantify the organismal and ecological impacts of key microplastics.

This project:

  • is focused on fresh water organisms and ecological interactions,
  • uses model fresh water species commonly found in Irish waters,
  • uses standardised (OECD) impact assays that generate standardised data,
  • compares the impacts of different plastics, and plastics of different sizes,
  • uses a holistic approach whereby impacts are quantified across a range of representative species and biological endpoints,
  • analyses impacts on habitats by measuring trophic interactions, including bioaccumulation

The data generated in this project will inform policy makers, enabling development of a targeted legislative approach that focuses on those microplastics that are of most environmental concern. Furthermore, the data generated will be a stepping stone towards biomonitoring and bioremediation approaches. This project will focus on developing more in-depth knowledge, which will further define the specifics of the pathways and the impacts of microplastics on humans, species and habitats.


Information on this project will be communicated on our website:

  • “Meet” the people directly involved in the project, and our collaborators.
  • Find our Publications on this project, and on ecotoxicology in general.
  • Keep up to date with our News.
  • Find information on other scientific research relating to this topic (via scientific articles), as well as reports in media articles, scientific reports, and videos. Links to these can be found on our Resources Page.