Microplastics in water: origin, risks, analysis, and treatment

Microplastics are polymeric particles generally smaller than 5 mm, produced directly at a small size or resulting from the fragmentation of waste, textiles, tires, paints, and packaging. They are detected in surface water, groundwater, tap water, and bottled water. Their diversity and the historical lack of harmonized methods make comparisons difficult. The European Union adopted a common measurement method in 2024, but no specific numeric parametric value has been set for drinking water as of July 2026.

Common size: Smaller than 5 mm
Major origins: Textiles, tires, and fragmentation
EU value: No numeric value
Methods: FTIR, Raman, pyrolysis-GC/MS

What are microplastics in water?

Microplastics are small solid particles made of synthetic or semi-synthetic polymers. The most common definition uses a size of less than 5 millimeters, although there is no universal lower limit applied in all studies.

They can appear as fragments, fibers, films, foams, beads, or pellets. Their composition, size, shape, density, and aging state determine their behavior in water and their ability to be removed by treatment.

Microplastics are not a single chemical substance. They encompass thousands of possible combinations of polymers, additives, colors, shapes, and dimensions. This diversity makes measuring them and evaluating their health effects highly complex.

Key takeaway: there is currently no numeric European parametric value for microplastics in drinking water. However, the European Union adopted a harmonized measurement method in 2024 to prepare for comparable monitoring among member states.

What is the difference between macroplastics, microplastics, and nanoplastics?

Category	Indicative size	Characteristics
Macroplastics	Larger than 5 mm	Visible waste: bottles, bags, packaging, fragments.
Microplastics	Smaller than 5 mm	Fragments, fibers, films, beads, and foams.
Small microplastics	Often smaller than 100 µm	Harder to detect and quantify.
Nanoplastics	Variable definition, often smaller than 1 µm	Nanometric particles, very difficult to measure in actual water.

The boundaries between categories vary by organization and analytical method. It is therefore essential to verify the size range studied before comparing two results.

Primary and secondary microplastics

Primary microplastics

These are manufactured directly as small particles. This category includes, in particular, certain industrial pellets, technical microbeads, and polymer powders.

Secondary microplastics

These result from the fragmentation of larger plastic objects due to UV radiation, heat, abrasion, waves, freezing, oxidation, and mechanical stress.

In the environment, a large proportion of microplastics are secondary. A single object can gradually fragment into smaller and smaller particles, down to the nanometric range.

What shapes are found in water?

Shape	Frequent origins	Possible behavior
Fibers	Textiles, ropes, nets, dust	Can remain suspended and pass through certain treatments.
Fragments	Degradation of packaging and objects	Irregular shape, variable density.
Films	Bags, agricultural films, packaging	Low thickness, variable buoyancy.
Beads	Industrial pellets and technical uses	Regular shape sometimes facilitating identification.
Foams	Expanded polystyrene, insulation	Often buoyant but susceptible to being coated in biofilm.

Which polymers are detected in drinking water?

Polymer	Abbreviation	Common uses
Polyethylene	PE	Films, bags, bottles, pipes.
Polypropylene	PP	Caps, containers, fibers, equipment.
Polyethylene terephthalate	PET	Bottles and textile fibers.
Polystyrene	PS	Packaging, foams, rigid objects.
Polyvinyl chloride	PVC	Pipes, coatings, cables.
Polyamide	PA	Textiles, nets, technical parts.
Polyester	PES	Textile fibers and fabrics.
Polyurethane	PU	Foams, coatings, and insulation.

The European Commission's Joint Research Centre cites polyethylene, PET, other polyesters, and polypropylene as polymers frequently observed in recent European studies on drinking water.

Where do the microplastics in water come from?

fragmentation of abandoned plastic waste;
wear of tires and road surfaces;
textile fibers released during washing and use;
paints, varnishes, and coatings;
industrial pellets lost during transport;
agricultural films and cultivation equipment;
atmospheric dust;
domestic and industrial wastewater;
urban and road runoff;
packaging and materials in contact with water.

Textile fibers and clothes washing

Synthetic textiles can release fibers during their manufacturing, wearing, washing, and drying. Fabrics made of polyester, polyamide, and acrylic are among the most studied sources.

The amount released depends on the type of fiber, the age of the garment, the wash cycle, temperature, spin speed, and the textile formulation.

Wastewater treatment plants retain a large portion of the fibers, but a fraction can remain in the effluent. Sludge also concentrates the captured particles.

Tire wear and road traffic

Friction between tires and the road surface produces particles containing a mixture of polymers, rubber, carbon black, mineral fillers, and additives.

These particles are transported by air or runoff into storm drains, rivers, soil, and groundwater. They constitute a major source of urban microplastics.

Their complex composition distinguishes them from conventional plastic fragments and makes their analytical quantification particularly difficult.

Paints, coatings, and road markings

Marine, road, architectural, and industrial paints often contain polymers. Their abrasion and aging release particles into the air, soil, and water.

Road markings and building coatings can contribute to urban runoff, especially during heavy rain.

Atmospheric transport of microplastics

Microplastics can be resuspended by wind, traffic, industrial activities, and surface erosion. Fibers and fragments have been detected in dust, precipitation, and regions far from large cities.

Atmospheric fallout can feed into rivers, lakes, reservoirs, and open water sources. It also constitutes a pathway for exposure through inhalation.

Wastewater treatment plants and microplastics

Wastewater treatment plants can retain a significant proportion of microplastics, thanks in particular to screening, settling, biological treatment, and tertiary treatment.

A high percentage of efficiency does not mean the absence of release, as the treated volumes are considerable. Part of the particles is transferred to the sludge.

In 2019, the WHO indicated that wastewater treatments could eliminate more than 90% of microplastics, with the highest performances associated with tertiary treatments. This value must be interpreted according to the sizes measured and the processes used.

Presence in rivers, lakes, and reservoirs

Surface waters receive inputs from wastewater, runoff, atmospheric deposits, navigation, fishing, and the fragmentation of waste.

Concentration can vary significantly depending on the season, flow rate, rain events, proximity to urban areas, and sampling method.

The particles can float, remain suspended, be transported over long distances, or settle in sediments.

Microplastics in groundwater

Groundwater is generally better protected than surface water, but it is not completely isolated. Microplastics can reach it through infiltration, fissures, karst, poorly protected wells, spreading of sludge, or exchanges with watercourses.

The smallest particles, fibers, and nanoplastics are likely to be more mobile. However, data remain limited and highly dependent on contamination risks during sampling.

Microplastics in tap water

Microplastics have been reported in some tap water, but results vary by several orders of magnitude depending on the studies.

This variability is explained by differences in the size ranges searched, volumes sampled, identification techniques, and contamination controls.

The European Union's Joint Research Centre indicated in 2024 that recent European studies generally reported low levels, sometimes between zero and 0.6 particles per liter for the size ranges studied.

Bottled water and microplastics

Microplastics may be present in bottled water. They can originate from the source, the bottling process, the cap, the bottle, or handling.

The number of particles measured increases sharply as methods reach very small sizes. Therefore, results from studies using different analytical thresholds should not be directly compared.

The presence of particles in bottled water does not, in itself, indicate a measurable health risk.

Can pipes release microplastics?

Networks made of polymer materials can theoretically release particles during manufacturing, aging, abrasion, or interventions on the network.

Seals, internal linings, tanks, domestic pipes, and equipment may also contribute to the particle load. The actual significance varies according to material, age, temperature, and hydraulic conditions.

Microplastics and biofilms

Plastic surfaces can be colonized by bacteria, algae, and other microorganisms. This complex is sometimes called the "plastisphere."

Biofilms modify the density, surface charge, and transport of particles. They can also promote their sedimentation or aggregation.

In drinking water, microbiological risk must be assessed independently. The presence of a microplastic does not automatically mean that it carries a pathogen.

Chemical additives associated with plastics

Plastics may contain plasticizers, flame retardants, pigments, UV stabilizers, antioxidants, mineral fillers, and other additives.

Some additives can migrate out of the polymer. Other contaminants present in the environment can also adsorb onto the surface of particles.

The health significance of this pathway depends on the concentration, bioavailability, and total exposure. It cannot be estimated solely from the number of particles.

What are the potential health effects?

Possible effects depend on the size, shape, polymer, dose, additives, and duration of exposure.

local irritation or inflammation;
oxidative stress;
immune effects;
transport of adsorbed additives or contaminants;
potential passage of very small particles through certain biological barriers;
microbiological effects related to biofilms.

The WHO concluded in 2019 that, based on the limited information available, microplastics in drinking water did not appear to pose a health risk at the levels then observed. However, it emphasized the numerous uncertainties and the need for further research.

In 2022, the WHO expanded its assessment to exposure through food and air, once again highlighting the limitations of available data, particularly for very small particles and nanoplastics.

Are microplastics absorbed by the body?

The majority of large ingested particles are expected to pass through the digestive system without being absorbed. The WHO indicated in 2019 that particles larger than 150 µm were unlikely to be absorbed.

Absorption could be more significant as size decreases, particularly in the nanometric range. However, human data remain insufficient to precisely quantify this passage and its consequences.

Detecting particles in biological tissue does not automatically prove a clinical effect. It requires rigorous validation of methods and contamination controls.

Why do nanoplastics raise more uncertainties?

Nanoplastics are small enough to interact differently with cells and biological barriers. Their specific surface area is high and their properties may differ from those of the original material.

They are extremely difficult to sample, identify, and quantify in environmental matrices. Routine methods do not yet allow for comprehensive and harmonized monitoring.

A result concerning particles larger than 20 µm does not imply the absence of smaller particles or nanoplastics.

How can the risk be contextualized in drinking water?

The WHO recommends maintaining priority on well-established microbiological and chemical risks, such as pathogens, arsenic, lead, or nitrates.

Processes that improve water clarification, filtration, and disinfection often also contribute to reducing microplastics. Therefore, a plastic pollution prevention policy offers broader environmental and health benefits.

What is the European regulation?

Directive (EU) 2020/2184 provides for the possibility of including microplastics in a watch list for water intended for human consumption.

On March 11, 2024, the European Commission adopted a delegated decision establishing a harmonized method for measuring microplastics in drinking water.

This method aims to produce comparable data before the potential definition of management or monitoring values. As of July 2026, there is no European numerical parametric value for microplastics in drinking water.

How does the 2024 European method work?

The European method is based on sampling large volumes of water and collecting particles in two size classes.

Element	General requirement
Sampling volume	At least 1,000 liters in the method developed by the JRC.
Filters	100 µm and 20 µm filters.
Size ranges	20–100 µm and greater than or equal to 100 µm.
Identification	Infrared microscopy or Raman microscopy.
Reported information	Polymer, size, shape, and number of particles.

This method does not necessarily cover particles smaller than 20 µm or nanoplastics.

What is the situation in the United States?

In April 2026, the Environmental Protection Agency proposed for the first time including microplastics as a priority group in the draft sixth Contaminant Candidate List, or CCL 6.

Inclusion on this list does not constitute a federal standard. It allows for prioritizing research, monitoring, and potential future regulatory decisions.

As of July 2026, the United States does not have a specific federal maximum concentration for microplastics in drinking water.

What is the WHO position?

The WHO does not currently set a numerical guideline value for microplastics in drinking water.

It recommends strengthening research, improving analytical methods, reducing plastic pollution, and continuing the optimization of water and wastewater treatment.

The WHO emphasizes that known microbiological risks must remain a priority while improving knowledge on micro- and nanoplastics.

Why is microplastic analysis complex?

historical lack of a uniform definition;
very different size ranges between studies;
multiple shapes and polymers;
high risk of contamination from air and clothing;
difficulty distinguishing certain natural or semi-synthetic fibers;
variable detection limits;
poor comparability between methods;
measuring nanoplastics is still very difficult.

How to avoid contaminating a sample?

use containers and devices validated by the laboratory;
avoid unprotected synthetic clothing;
limit sample exposure to air;
perform field and laboratory blanks;
thoroughly clean all equipment;
use filtered water for analytical rinses;
document materials present during sampling;
work in a controlled environment when necessary.

Visual microscopy: advantages and limitations

Microscopy allows for counting and classifying particles according to their shape and color. It is fast for large particles, but does not prove that a particle is actually made of plastic.

Spectroscopic confirmation is recommended. The risk of error increases sharply for small particles and transparent fibers.

Infrared spectroscopy and micro-FTIR

Infrared spectroscopy identifies a polymer based on its molecular spectrum. In FTIR microscopy, analysis can be automated across a filter surface.

This technique is commonly used for particles of a few tens of micrometers and larger. Its resolution depends on the system, substrate, and condition of the particle.

Raman microscopy

Raman microscopy allows the identification of particles smaller than those generally accessible via FTIR. It also provides chemical information about the polymer.

Pigments, fluorescence, particles burned by the laser, and analysis time can limit the method.

Pyrolysis-GC/MS and mass methods

Pyrolysis coupled with gas chromatography and mass spectrometry decomposes polymers and identifies their characteristic products.

It measures a mass of polymer but generally does not provide the number, size, or shape of particles.

Therefore, mass results and particle number results are not directly interchangeable.

How to interpret a result?

Information to check	Why is it essential?
Unit	Particles/L, particles/m³, µg/L, or mg/L are not equivalent.
Minimum size	The lower the threshold, the more the measured number increases.
Polymers included	Some protocols exclude paints, rubbers, or semi-synthetic fibers.
Shapes counted	Fibers, fragments, films, and foams may be reported separately.
Volume sampled	A large volume improves representativeness when concentrations are low.
Analytical blanks	They allow for the correction of background contamination.
Identification method	Microscopy alone is less specific than FTIR or Raman.

Coagulation, flocculation, and sedimentation

Coagulation destabilizes particles and promotes their grouping into flocs. Sedimentation or flotation then allows for the removal of some microplastics.

Performance is generally better for larger, denser particles or those easily incorporated into flocs. Small fibers and low-density particles are more difficult to remove.

Sand filtration and granular filtration

Rapid or slow sand filters can retain a portion of microplastics after coagulation or clarification.

Efficiency depends on particle size, filtration speed, media, clogging, and the presence of a biofilm.

Microfiltration, ultrafiltration, and membranes

Microfiltration

It can retain particles larger than the effective pore size. Very small particles and nanoplastics may pass through depending on the membrane.

Ultrafiltration

It offers a finer barrier and can retain a significant portion of microplastics and certain small fragments.

Nanofiltration and reverse osmosis

These membranes have high potential for very small particles. Integrity, seal, pressure, and maintenance are decisive factors.

Concentrate management

Membrane processes move particles into wash water or concentrate, which must be managed properly.

Activated carbon and microplastics

Activated carbon is designed primarily to adsorb dissolved organic contaminants. It can contribute to the physical retention of certain particles when used in block or granular bed form, but this function should not be extrapolated to all sizes.

Performance depends on porosity, filter structure, flow rate, the presence of a final barrier, and the test protocol.

Ceramic filtration and microporous barriers

A microporous ceramic can retain particles larger than its effective pores. It can therefore constitute a barrier against a portion of microplastics.

It does not allow for a conclusion of reduction for all particles, particularly those smaller than the filtration threshold, nanoplastics, or deformable fragments.

A performance claim must specify the size tested and the total volume treated.

Does boiling eliminate microplastics?

Boiling alone does not destroy polymers. It may modify the aggregation of certain particles in the presence of minerals, but it is not a universal or validated treatment method.

If water evaporates, non-eliminated particles remain in the remaining volume. Controlled filtration would be necessary to remove any aggregates that may have formed.

Comparison of treatment technologies

Technology	General potential	Limitations
Coagulation–flocculation	Good for certain particles	Depends on size, shape, and dosage.
Decantation / flotation	Variable	Low efficiency on light or very small particles.
Sand filtration	Moderate to high	Depends on pretreatment and media.
Microfiltration	High for particles larger than pores	Does not necessarily cover the smallest sizes.
Ultrafiltration	High	Membrane integrity and clogging.
Nanofiltration	Very high for many sizes	Pressure, rejection, and maintenance.
Reverse osmosis	Very high	Concentrate management and membrane monitoring.
Carbon block	Variable	Depends on structure and particle size.
Microporous ceramic	Variable based on threshold	Proves nothing for particles below the threshold.
Boiling	Not reliable	Does not destroy polymers.
UV	Ineffective as filtration	Disinfection without physical removal.

How to evaluate a filter against microplastics?

A general claim of microplastic reduction should be examined with caution. The result depends primarily on the minimum size tested.

Item to verify	Importance
Size range	A test at 5 µm proves nothing for 1 µm particles.
Particle type	Standardized beads, fragments, and fibers behave differently.
Polymer used	Density and surface influence retention.
Inlet concentration	The test must be measurable and representative.
Outlet concentration	Allows for calculating the actual reduction.
Total volume treated	Performance may evolve with clogging or wear.
Flow rate	Influences retention and contact time.
Analytical method	FTIR, Raman, or other methods must be specified.
End-of-life result	Initial performance is not enough.

The performance of a filtration system must be evaluated based on specific tests conducted by its manufacturer. In the absence of published results regarding this contaminant, no numerical reduction can be claimed.

Consult Monderma certifications and analyses

Filter maintenance and risk of release

A poorly maintained filter can lose flow, become clogged, or release particles from its own materials.

respect the indicated usage period;
rinse cartridges according to instructions;
avoid flow rates higher than those tested;
replace damaged elements;
clean housings and pipes;
perform analyses when the issue justifies it;
use only compatible parts suitable for food contact.

How to reduce microplastic discharges?

reduce the use of disposable plastics;
prevent industrial pellet losses;
improve collection and recycling;
limit tire abrasion and optimize mobility;
equip rainwater networks with retention systems;
improve tertiary wastewater treatment;
reduce textile fiber losses;
control paints and coatings;
protect water catchments from waste and runoff.

What can an individual do?

avoid heating food in plastics not intended for this purpose;
replace heavily worn or scratched containers;
wash synthetic textiles with appropriate cycles;
reduce disposable products;
properly maintain household filters;
do not interpret a simple sediment filter as protection against all sizes;
prioritize professional analyses when local exposure is suspected.

Frequently asked questions about microplastics in water

What size defines a microplastic?

The most common definition uses a size of less than 5 mm.

What is a nanoplastic?

A plastic particle of nanometric size, often defined as less than 1 µm, depending on the organizations.

Are microplastics visible?

The largest ones can be, but the majority of studied particles require a microscope.

Where do fibers in water come from?

Mainly from textiles, dust, ropes, and effluents.

Do tires produce microplastics?

Yes, their abrasion releases complex polymeric particles.

Does tap water contain microplastics?

Studies have detected them, but levels vary according to methods and networks.

Does bottled water contain them?

Particles have been measured in some bottled waters.

Can two studies be compared directly?

Only if the sizes, units, methods, and contamination controls are comparable.

Is there a numerical European standard?

No, not as of July 2026.

Does the European Union monitor microplastics?

It adopted a harmonized measurement method in 2024 for monitoring purposes.

What size does the European method cover?

It notably uses size classes of 20 to 100 µm and 100 µm and above.

Does the WHO set a guideline value?

No.

Are microplastics dangerous?

Knowledge remains insufficient to precisely quantify the risk at the levels observed in drinking water.

Are large particles absorbed?

They are generally unlikely to be absorbed by the intestine.

Are nanoplastics more concerning?

They could more easily cross certain biological barriers, but data is still limited.

Do microplastics carry bacteria?

They can carry biofilms, without this automatically meaning a pathogenic risk.

Do microplastics carry chemicals?

They can contain additives and adsorb certain contaminants.

Does a wastewater treatment plant remove them?

It can retain a large portion, especially with tertiary treatment.

Does a drinking water plant remove them?

Treatments combining coagulation, decantation, and filtration can remove a large portion.

Is a sediment filter enough?

It only retains particles larger than its actual threshold.

Does a ceramic filter remove them?

It can retain particles larger than its pores, but not all sizes.

Does activated carbon remove them?

Physical retention is variable and must be demonstrated by a specific test.

Does reverse osmosis remove them?

It has high potential when the membrane is intact and correctly used.

Does boiling destroy them?

No.

Do UVs destroy them?

Domestic UV disinfection is not a removal treatment.

How are microplastics measured?

By microscopy coupled with FTIR or Raman, or by mass methods such as pyrolysis-GC/MS.

Why must a large amount of water be sampled?

Because concentrations can be low and heterogeneous.

What does particles per liter mean?

The number of particles counted in a liter according to a defined size range.

How to choose a filter?

Check the tested size, volume treated, analytical method, and end-of-life results.

Can microplastics be totally eliminated?

No process allows for claiming the absolute absence of all sizes, particularly nanoplastics.

Scientific and administrative sources

World Health Organization – Microplastics in drinking-water
Consult the 2019 WHO report
World Health Organization – Dietary and inhalation exposure
Consult the 2022 WHO report
World Health Organization – Plastics and Health Initiative
View WHO initiative
European Union – Directive (EU) 2020/2184
View Drinking Water Directive
European Commission – Delegated decision on microplastics measurement
View 2024 European method
Joint Research Centre – Harmonized European method
View JRC presentation
European Commission – Microplastics and the environment
View European actions
US EPA – Draft Fifth Contaminant Candidate List
View April 2026 EPA announcement
Monderma – Certifications and laboratory analyses
View Monderma certifications and analyses

Contaminants and associated parameters

PFAS Pesticides Lead Cadmium Chromium Nitrates Turbidity Bacteria

Scientific disclaimer: analytical methods and health-related knowledge regarding micro- and nanoplastics are evolving rapidly. Results are only comparable when size ranges, units, polymers, and protocols are identical. This sheet does not replace laboratory analysis or the advice of health authorities.