INSIGHT by Anna MacDonald, PhD researcher at the University of Strathclyde, Scotland

A recent study from researchers at the University of Strathclyde, Glasgow, provides new evidence that recycling facilities could be a point source for further microplastic pollution into our environment. This highlights the lack of understanding of the impact of our recycling, and the need for more research and regulation into waste management processes.


One recycling facility potentially discharging 59-1184 tonnes of microplastics per year


The paper published by Erina Brown and colleagues, states that there is a potential microplastic (MP) discharge of 59-1184 tonnes per year, even with remediation measures in place. The study published in the Journal of Hazardous Materials in May 2023,  investigated the raw waste water from a recycling facility to examine the potential of further plastic contamination from recycling processes. The wash water was also examined after the installation of a filtration remediation system. Although filtration had a high removal efficiencies for particles above 40µm in size, particles below 10µm were not removed by the filtration and subsequently discharged. This missing fraction accounted for up to approx. 5% of the plastic entering the recycling facility. This rises up to 13% if there is no filtration in place. This pilot study demonstrates the need for more investigation into the discharges from recycling processes.


Microplastics were found in all samples and can be seen here with the use of a microscope. The bottom image shows plastic particles in fluorescent green, with the aid of  Nile Red dye, the method used to identify the microplastics in the study.


Microplastic leakage accounts for approximately 5% of the total plastic entering the facility with remediation filtration measures in place. This jumps to 13% if no filtration system exists.


When compared to local wastewater treatment plant (WWTP) numbers, the reported results were several magnitudes higher even with the filtration system in place. Given the high number of MPs emitted from this point source, MP monitoring should be included as a standardised measure of water quality. To date, there are no regulations in place for recycling facilities or consistent environmental monitoring for microplastics in the environment. This includes wash water, the media studied in this paper. There is already a demand for tighter regulation on microplastics and this will only grow as the world learns more about this pollutant. Therefore, there is a need for more research into MP contamination from recycling plants, not only from wash water, but atmospheric emissions also. In conjunction with this, filtration measures need to be commonplace as a precautionary measure before the true extent of MP leakage to environment is examined and quantified regionally and globally. Although this filtration remediation may be effective in removing particles >40µm, investment is needed into improving filtration and remediation systems for particles below this threshold, and a system designed to manage this filtered MP waste. As particles move into the <10µm size fraction, they become especially relevant for public health, as they are more easily ingested and absorbed into the body. This size is also pertinent for environmental risk as it is easily ingested by organisms exposed to the pollutant and can be easily transported up to thousands of kilometres away due to its small size; meaning the damage to ecosystem health can be immediate and also be felt in more distal destinations. The quantity of microplastics also increase as the size decreases, meaning that size is important in terms of accurately reporting concentrations and assessing impact.


Filtration can effectively remove particles above 40µm in size, but is less effective at removing smaller particles. This was especially true for particles below 10µm which are most hazardous for public health and environmental transport.


Currently the environmental regulations on microplastics in general are limited, with the main focus being ‘microbeads’ from cosmetic products which were banned in the UK in 2018, and restricted by the European Chemicals Agency (ECHA) in 2019. Several countries, such as France, have also made commitments to reduce microfibre pollution from clothing and clothes washing coming into force in 2025. The European Commission is in the process of drafting legislation, to introduce measures to cut the volume of MPs released into the environment by 2030. However, some countries feel that this is not enough. In April this year, five countries (Germany, the Netherlands, France, Denmark, Luxembourg and Norway) signed a joint paper to call for European measures that go beyond voluntary actions. This paper also calls for uniform systems to monitor MP in air, water, and soil. This action is reflected within the microplastics discipline itself, which given its novelty, does not have a systematic approach the measurement of the pollutant. This challenge will become more important as the world learns more about the extent of microplastic contamination and the associated risks.


Recycling should not be the first priority for an effective circular economy. Alternatively, investment in reducing waste, prolonging product lifetime and refurbishment should be the focus. Investment is also needed to ensure recycling does not add to our growing environmental waste problem.


This issue also highlights that recycling, although a crucial part of a functioning circular economy, has its own related hazards, and both regulation and technology are needed to ensure it does not add to an already growing waste management problem. As is consistent with the principals of the circular economy, recycling is not to be the first line of defence when it comes to environmental protection. In an effective circular economy, reducing waste first should be the focus. Following this, investment in prolonging the lifetime of products, redistribution of resources and refurbishment should be a priority, alongside improving recycling and remediation technologies. Given that approximately 45% of waste in the UK is classified as recycled, ensuring that these processes are providing more benefit than cost, is a priority.


>>click to zoom in


Going forward the following recommendations are made:

More research into MP leakage from recycling and waste management facilities

Integration of MP monitoring into water quality regulations

Lower acceptable and expected detectable range of microplastics to be in the sub-20µm range – the lower the better

Shifting the waste management focus to the circular economy – reuse, redistribution and remanufacturing first

More investment into technologies to improve filtration and remediation, and environmental monitoring


| authors

Erina Brown, the lead author of the paper, carried out this research at the University of Strathclyde, Glasgow. She is currently working at Atkins and is applying her interest and experience in microplastic pollution in water to the bioresources and wastewater sector. She is soon starting PhD research with the University of Birmingham in microplastic pollution in groundwater whilst continuing her work in the wastewater sector and involvement in the sector beginning to adapt to managing emerging contaminants.

Anna MacDonald is a PhD researcher at the University of Strathclyde, Scotland. Her research is focused on atmospheric microplastics, specifically the methods used to measure their presence in our atmosphere. She is also interested in the global burden of this emerging pollutant and has undertaken various field campaigns to investigate the varying levels of contamination in different climates. Her research has also investigated the role of behaviour change in plastic use and pro-environmental behaviour.

Dr. Deonie Allen is an MSCA Global research fellow working with the University of Birmingham (UK) and the University of Canterbury (NZ). Her research has focused on environmental pollution and pollution transport in urban and remote locations, specifically man-made pollutants, and how they influence environmental health, ecosystem function, sustainable and circular economy actions. Her current research focus is on microplastic pollution and its cyclic transport; in the air, water and soil/sediment. Deonie is a member of the GESAMP (UN Group of Experts on the Scientific Aspects of Marine Environmental Protection) working group 38 and an affiliated researcher with the University of Strathclyde and Dalhousie, supporting an international range of microplastic projects.


All opinions expressed are those of the author and/or quoted sources. is an independent and neutral platform dedicated to generating debate around ESG investing topics.