Plastic and microplastic pollution has become a threat to global ecology. Microplastics are also a cause for health concern. But what are the sources of microplastics? And how can microplastic pollution be prevented?
Table of Contents
Understanding Microplastics
Plastic is a serious threat to our environment, especially to freshwater ecosystems. Microplastics (MPs) are tiny plastic particles. “MPs” is the standard abbreviation used in scientific research and water testing reports. MPs range from 1 micron to 5 millimetres in size and can be classified into primary MPs and secondary MPs. Primary MPs are plastics that have been manufactured small. Secondary MPs result from the breakdown of larger plastic items. Rivers are significant pathways for MP pollution, causing marine litter. Much of the Irish data in this article comes from the EPA’s 2023 research report, Sources, Pathways and Environmental Fate of Microplastics.
The Dangers of Microplastic Pollution
MPs pose significant risks to wildlife and humans. Studies have found MPs in various river-dwelling creatures, including 72% of brown trout and 53% of otter spraints. MPs also move up the food chain, reaching top predators once they eat prey containing MPs. Around 80% of Ireland’s public drinking water comes from surface water, mainly rivers and lakes. As a result, MPs can often end up in our bodies too. A 2022 Dutch study detected plastic particles in the blood of 17 of 22 donors (77%). Research has linked the presence of MPs in arteries to a higher risk of heart attacks and strokes.
Sources of Microplastic Pollution
Wastewater Treatment Plants (WWTPs)
WWTPs capture a large portion of MPs. 97-99% of MPs are retained in sludge during primary treatment. However, this sludge is often spread on land, reintroducing MPs into the environment. Additionally, MPs that do escape WWTPs can end up in our rivers.
Construction Industry
The construction industry in Europe consumes 10 million tonnes of plastic each year. Plastic pipes account for over 50% of annual tonnage. Cutting these materials during construction produces and releases MPs.
Artificial Grass Pitches
Artificial grass pitches are increasingly replacing natural pitches. Over the last decade, artificial pitches have become a popular choice for community sports. The artificial grass turf comprises plastic. These pitches can contain up to 140 tonnes of plastic material. As they wear down, they release MPs into the environment.
Synthetic Textiles and Tyre Wear
Globally, synthetic textiles and vehicle tyres are the two largest sources of primary MPs. The International Union for Conservation of Nature (IUCN) estimates that synthetic textiles account for 35% and tyre wear for 28% of primary MPs released to the oceans. Washing synthetic clothing releases microfibres into wastewater, while tyres shed particles through abrasion on road surfaces. These particles reach rivers through WWTPs and road runoff.
How Microplastics Are Measured in Water
Measuring MPs in water is more complex than most routine water tests. Samples are passed through fine filters to collect particles, which are then counted, sized and identified by polymer type. The main analytical techniques are Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and pyrolysis gas chromatography mass spectrometry (py-GC/MS). FTIR and Raman identify individual particles by size and plastic type, while py-GC/MS measures the mass concentration of specific polymers. Strict contamination controls are essential, as MPs are present in laboratory air and equipment.
Until recently, there was no harmonised approach to measuring MPs in drinking water. In 2024, the European Commission adopted Delegated Decision (EU) 2024/1441, which sets out a standard methodology for measuring MPs in water intended for human consumption under the recast Drinking Water Directive (EU) 2020/2184. The method requires sampling at least 1,000 litres of water and reports results as the number of MPs per cubic metre, classified by size, shape and polymer type. The methodology was developed with a view to adding MPs to the EU drinking water watch list, which would require Member States, including Ireland, to monitor them.
Preventing Microplastic Pollution
Improving Wastewater Treatment
To reduce MP pollution, we need better water monitoring data. Such data will help to see how different treatment levels (primary, secondary, tertiary) affect MP removal. Policies should also aim to reduce microfibres entering WWTPs. This may be achieved by adding filters to washing machines, for example.
Managing Construction Sites
Construction sites should conduct waste audits to understand and reduce MP production. Building information models can minimise the need to cut plastic materials. Reducing plastic cutting will decrease MP waste.
Enhancing Artificial Pitches
Artificial pitches should have built-in drainage systems with sand to trap MPs. Installing steel boot-cleaning grids would reduce crumb transfer from the pitch. Retainer walls can also help minimise crumb and MP spread. Under EU Regulation 2023/2055, the sale of granular infill for synthetic sports surfaces will be banned from 17 October 2031.
Conclusion for Microplastic Pollution
Continuous monitoring in river catchments is essential to combat microplastic pollution. This monitoring should be part of river basin management plans in Ireland. Monitoring followed by interventions will reduce the ecological impact of MPs.
With over 30 years of experience, Southern Scientific is an INAB-accredited laboratory operating to ISO 17025, analysing over 10,000 drinking water samples each year. Our Chemical & Environmental Testing and Environmental & Testing Consultancy services support water monitoring programmes and help organisations understand and reduce their environmental impact.
