Managing microplastics before regulation catches up
At a glance
Microplastics are fine particles generally less than 5mm in size that are present across water, soil, air and biological systems. Scientists are still working to understand how these particles move through the environment, their fate and transport behaviour, and what their impact means for human and ecological health.
Microplastics regulation is beginning to take shape, but health-based definitions and a universal testing methodology still remain major hurdles, with methods to characterise microplastics varying between different regions. Rather than waiting for a complete regulatory framework, organisations should begin establishing baseline data and building their understanding of microplastics now.
Microplastics are fine particles generally less than 5mm in size that are present across water, soil, air and biological systems. Scientists are still working to understand how these particles move through the environment, their fate and transport behaviour, and what their impact means for human and ecological health.
Why microplastics are drawing attention
The world produces more than 430 million tonnes of plastic each year. While plastic is a long-lasting material, over time, natural processes like sunlight exposure, weathering and physical abrasion gradually break plastic into smaller fragments that can now be detected throughout environmental systems. These are collectively referred to as microplastics.
Microplastics are often treated as a single type of contaminant, but in reality, they represent a highly diverse group of particles. They include particles and fibres with different characteristics and environmental behaviours. They can come from cosmetic products, synthetic textiles, tyres or the breakdown of bulk plastic items. Size, shape, polymer type and surface chemistry all influence how microplastics move through the environment and respond to potential treatment processes. These characteristics can also change over time as particles age and fragment.
Once microplastics enter the environment, the particles and chemicals associated with them can create wider risks. Many plastics contain additives that improve processability, durability and performance. As materials break down, these additives can be released or transformed into compounds with different environmental properties. Some of these additives, such as certain plasticisers, flame retardants and stabilisers, have been associated with environmental or human health concerns, adding another layer of complexity to understanding the potential impacts of microplastics.
Microplastics can also absorb other co-contaminants, such as PFAS and toxic heavy metal ions and transport them through the environment, making them part of a wider contaminant issue that requires thorough risk assessment and management.
Scientists are also studying what happens when the smallest particles enter the human body. Nanoplastics (a subset of microplastics with the size <1000nm) have been identified in human brain tissue, with studies observing higher concentrations in people with dementia. While these findings show correlation rather than causation, they have intensified interest in understanding long-term exposure and potential health impacts.
Microplastics are often treated as a single type of contaminant, but in reality, they represent a highly diverse group of particles. They include particles and fibres with different characteristics and environmental behaviours. They can come from cosmetic products, synthetic textiles, tyres or the breakdown of bulk plastic items. Size, shape, polymer type and surface chemistry all influence how microplastics move through the environment and respond to potential treatment processes. These characteristics can also change over time as particles age and fragment.
Once microplastics enter the environment, the particles and chemicals associated with them can create wider risks. Many plastics contain additives that improve processability, durability and performance. As materials break down, these additives can be released or transformed into compounds with different environmental properties. Some of these additives, such as certain plasticisers, flame retardants and stabilisers, have been associated with environmental or human health concerns, adding another layer of complexity to understanding the potential impacts of microplastics.
Microplastics can also absorb other co-contaminants, such as PFAS and toxic heavy metal ions and transport them through the environment, making them part of a wider contaminant issue that requires thorough risk assessment and management.
Scientists are also studying what happens when the smallest particles enter the human body. Nanoplastics (a subset of microplastics with the size <1000nm) have been identified in human brain tissue, with studies observing higher concentrations in people with dementia. While these findings show correlation rather than causation, they have intensified interest in understanding long-term exposure and potential health impacts.
The problem with defining and measuring microplastics
There is still no consistent definition of a microplastic. Some jurisdictions focus on particle size, while others also consider shape or fibre characteristics. But physical traits alone may not describe the particles that matter most from a health and environmental perspective because the factors that influence risk extend beyond size and shape.
Measurement adds another challenge because different analytical techniques capture different particle populations. Compared to other contaminant analysis, microplastics analysis is a labour-intensive process which generally involves size separation, removal of organic matter, density separation, filtration and spectroscopic identification.
Laboratories may report different results because they use different techniques and particle-size thresholds, meaning a reported reduction can depend as much on how a sample was analysed as what was actually present.
Current science cannot yet identify with confidence which particles present the greatest risk as it depends on particle size, shape, polymer composition, surface chemistry and the contaminants attached to the particle. Exposure can also occur through multiple pathways, including water, food, air, soil and consumer products, making them part of a contaminant class that doesn’t fit cleanly within conventional risk-assessment frameworks.
Nanoplastics add another layer of complexity because they are smaller and may behave differently from larger particles. Existing commercial monitoring methods often focus on larger particle ranges even as scientific interest is shifting toward particles measured at the nanoscale.
Measurement adds another challenge because different analytical techniques capture different particle populations. Compared to other contaminant analysis, microplastics analysis is a labour-intensive process which generally involves size separation, removal of organic matter, density separation, filtration and spectroscopic identification.
Laboratories may report different results because they use different techniques and particle-size thresholds, meaning a reported reduction can depend as much on how a sample was analysed as what was actually present.
Current science cannot yet identify with confidence which particles present the greatest risk as it depends on particle size, shape, polymer composition, surface chemistry and the contaminants attached to the particle. Exposure can also occur through multiple pathways, including water, food, air, soil and consumer products, making them part of a contaminant class that doesn’t fit cleanly within conventional risk-assessment frameworks.
Nanoplastics add another layer of complexity because they are smaller and may behave differently from larger particles. Existing commercial monitoring methods often focus on larger particle ranges even as scientific interest is shifting toward particles measured at the nanoscale.
Regulation is taking shape, but slowly
Regulation is beginning to catch up, but progress varies considerably between jurisdictions. In 2024, the European Union adopted a formal drinking-water measurement methodology and introduced wastewater monitoring requirements through its revised Urban Wastewater Treatment Directive.
In the United States, California has been testing drinking water supplies since 2023, while on the federal level, microplastics appeared in the draft of the sixth Contaminant Candidate List (CCL6). It was ultimately excluded from the proposed UCMR 6 because a validated drinking-water monitoring method was unavailable.
Scientific understanding of microplastics is advancing quickly, but regulation still lags in many jurisdictions. As a result, many organisations are caught between growing awareness and limited certainty.
In the United States, California has been testing drinking water supplies since 2023, while on the federal level, microplastics appeared in the draft of the sixth Contaminant Candidate List (CCL6). It was ultimately excluded from the proposed UCMR 6 because a validated drinking-water monitoring method was unavailable.
Scientific understanding of microplastics is advancing quickly, but regulation still lags in many jurisdictions. As a result, many organisations are caught between growing awareness and limited certainty.
The challenge doesn't end at treatment
As we’ve seen with per and polyfluoroalkyl substances (PFAS), regulatory and public expectations can evolve rapidly despite scientific uncertainty. Microplastics may be on a similar trajectory.
When considering treatment technologies, high removal rates reported can create a false sense of confidence. Treatment may remove particles from the water stream without resolving the wider problem, instead concentrating them in sludge and biosolids. Differences in sample preparation and analysis can also make studies appear contradictory when they’re measuring different particle populations.
The most important thing to understand is where microplastics end up once they leave the water stream. This overlaps with the work many organisations are doing around biosolids and emerging contaminants like PFAS, where reliable testing is equally important. The broader lesson is that sound decisions depend on understanding what a test is actually measuring.
When considering treatment technologies, high removal rates reported can create a false sense of confidence. Treatment may remove particles from the water stream without resolving the wider problem, instead concentrating them in sludge and biosolids. Differences in sample preparation and analysis can also make studies appear contradictory when they’re measuring different particle populations.
The most important thing to understand is where microplastics end up once they leave the water stream. This overlaps with the work many organisations are doing around biosolids and emerging contaminants like PFAS, where reliable testing is equally important. The broader lesson is that sound decisions depend on understanding what a test is actually measuring.
Key takeaways
The science is still evolving, but there are three practical considerations organisations dealing with microplastics should know:
- Health-based definition and consistent testing methods remain a key challenge. Microplastics complicate many of the assumptions that underpin traditional contaminant management and our current understanding of microplastics cannot even agree which particles present the greatest risk.
- Existing treatment doesn’t always eliminate the problem. For example, wastewater treatment can remove microplastics from the water phase, but it may just deposit them into sludge and biosolids. Approaches that focus on long-term management are still needed.
- Monitoring results can be difficult to compare. Different methods target different particle sizes and laboratories may use different analytical approaches, making it difficult to draw direct comparisons between datasets.
Asset owners shouldn’t wait for regulatory certainty before building their understanding of microplastics. A practical starting point is to establish the baseline information by identifying where microplastics enter operations and where they go after leaving the water stream. For many operators, that means looking beyond treatment performance to biosolids management and existing contaminant monitoring programs.
The regulatory landscape is very dynamic, but expectations are moving in one direction. Organisations that understand how microplastics move through their systems will be better placed to respond as regulation catches up.
Watch our Accredited Technical Masterclass on-demand for a deeper exploration of the science, challenges and implications of microplastics.