Recently, models on the fate of tyre wear particles (TWPs) have estimated that 18% of TWP emissions are transported from roads to freshwater bodies and approximately 2% are led out to estuaries and then marine habitats. What then happens to the remaining 16% of TWP emissions left in the freshwater compartment is not yet clear

The presence of tyre wear particles (TWP) in the aquatic environment is considered an emerging contaminant, and one that has gained increasing interest during the past few years. Although the presence of TWPs in the environment is given greater attention these days, TWPs have probably been present since the dawn of the pneumatic car tyre production in the late 19th century. The first scientific report of tyre dust identification along a roadside was published in 1961. Different perspectives have since been applied to this field of research and almost decade by decade shifted foci from degradation patterns to heavy metal release, to impacts of scrap tyres on the aquatic environment and leaching of chemicals from tyres. More recently, research within this field has been directed towards repurposing scenarios using crumb rubber in turf fields and playground material. Finally, in the 2010s, micronised tyre rubber has become grouped with other polymer debris and hence become part of the polymer landscape usually referred to as ‘microplastics.’ TWPs are considered to represent the majority of microplastics (or polymer debris) in the environment, and the newest calculation on the wear of tyres is estimated at 0.81 kg per person per year.

Now, looking at TWPs through the lens of microplastic pollution, research and information from the microplastics field are very well applicable to TWPs in many instances. With this new perspective of TWPs, increasing awareness of possible adverse effects in the environment follows - how do TWPs distribute in the different environmental compartments (soil, air, sediment, water and biota (living organisms)) and how do TWPs behave when exposed to different abiotic factors in these environmental compartments. For example, UV-radiation or pH, temperature and salinity differences could affect TWPs, but to what degree? A recent paper on this very subject concluded that particularly temperature and mechanical stress could influence the toxicity of TWPs. The focus of tyre production and function have seemingly always been directed towards maximising the three hallmarks: grip, wear and rolling resistance, and rightfully so, but somewhere along the road we forgot to consider where tyre abrasion actually disappears to. Luckily, some scientists already thought of this and today we can begin to lay the foundation to our collected TWP knowledge, based on the available scientific literature.

From roads to water

Research shows that the minority of TWPs end up in the airborne fraction (0.1-10%) and recently TRWPs have been assessed to contribute a low risk to human health in the particulate matter (PM) PM2.5 and PM10 range. So, where to find the remaining 90.0-99.9% of tyre debris emissions? Early research on particulate distribution showed a decreasing concentration of TWPs with increasing distance from the road. From there, TWPs are expected to wash off during rainfalls, transporting them to different environmental compartments. Recently, models on the fate of TWPs have estimated that 18% of TWP emissions are transported from roads to freshwater bodies and approximately 2% are led out to estuaries and then marine habitats. What then happens to the remaining 16% of TWP emissions left in the freshwater compartment is not yet clear and more research is needed to answer this question.

Aquatic organisms living in the water column or the sediment can interact with TWPs in their natural habitats during this particle transportation through freshwater to the marine environment. Although there are no scientific references on field observations of TWP ingestion by aquatic biota yet, few recent observations of this behaviour under controlled laboratory settings have been reported. In 2009 the first observation of the water flea, Daphnia magna, ingesting TWPs was described in the scientific literature and only two years ago the first photos were published showing ingestion of TWPs in the benthic amphipod Gammarus pulex following sediment exposure. Shortly thereafter photos of TWP ingestion in the amphipod Hyalella azteca and opossum shrimps from the mysidae family followed after water-only exposures, and most recently freshwater and marine fish species have been documented ingesting TWPs under laboratory conditions.

The recent focus on particulate effects of TWPs on biota is still in its infancy and the latest development in this field investigates the possible effects of both the particulate fraction and the leachate fraction. The leachate fraction is the suite of chemicals that leach out from TWPs to the surrounding water. Previously, tyre toxicity investigations in the aquatic environment revolved solely around the leachate fraction, which has been the primary focus over the last 30 years. Among the first papers the effect of whole tyre leachate was investigated showing worn tyre leachate to exhibit greater toxicity than leachate from a pristine tyre to rainbow trout. Furthermore, decreasing toxicity was observed with increasing salinity indicating that salinity either influences the leachability of toxic constituents or that an interaction of salts and toxic chemicals is present. Exposure of shredded tyre chips to different bacteria likewise showed a correlation between decreasing toxicity and increasing salinity, concluding that tyre leachate is likely to be a greater threat to freshwater habitats than to estuarine or marine habitats.

Toxicity pattern

Further testing of TWPs and leachate on a freshwater species recently showed a dissimilar toxicity pattern when comparing acute toxicity responses of TWPs or leachate. Here, the amphipod H. azteca was exposed to either TWPs in freshwater or the leachate fraction alone, i.e. with no particulates present. This showed that leachate was more toxic in lower concentrations, presumably because dissolved chemicals are more bioavailable. Although, at higher concentrations, the particle fraction of TWPs became more toxic. This phenomenon very well describes the complexity and discrepancies when working with TWPs in the aquatic environment. It is not just a question of determining toxicity of a single chemical under controlled settings, but rather investigating a mixture of many chemicals in changing ambient environments. This complex matrix of polymer and chemicals can be more or less bound to the particle, which in itself might have adverse effects. However, the particle could also function as a vessel, containing chemicals and making them more or less bioavailable depending on the surrounding environment. Discovering exactly which chemicals leach out under different exposure scenarios, and most importantly, what of that is actually bioavailable to aquatic living species is the more interesting question to answer.

Due to the amorphous nature of rubber, end-of-life tyres (ELTs) have been used as leachate collection material and been used to collect polycyclic aromatic hydrocarbons (PAHs) and metals from contaminated waters. This discrepancy between the different TWP uses that in some cases could deem toxic and have adverse effects but at the same time might serve to mitigate other environmental issues is a great conflict of contradictory traits. Now, we need to unravel exactly when these contradictory traits are possibly affecting aquatic environments negatively and when these traits might be used for our advantage.

So how do scientists quantify TWPs and chemical constituents or ‘biomarkers’ from TWP leachate in water? The quick answer is that no tried and tested procedure is more right than any other now, we simply do not have conformity or guidelines on how to do this. Especially when looking to find particulates from tyre debris, as this is not usually detected when investigating for other polymer debris e.g. microplastics. Therefore, it is expected that the total amount of microplastics has been underestimated due to the lack of data from TWPs, which make up a large part of the estimated microplastic load worldwide and have not been reported on a regular basis. A multitude of methods have been used to estimate TWP emissions by measuring the concentration of chemicals in samples, with more or less success over the years. The biomarkers that have been used to determine TWP concentration most successfully include quantification of benzothiazoles and zinc. Both chemicals are used as part of the vulcanisation process and are also ubiquitous in nature. They are used for manufacturing of other materials, but specific versions can be attributed mainly to tyre manufacturing and are thus the most reliable compounds to measure.

How this emerging field of tyre ecotoxicology will progress ultimately depends on cooperation between different stakeholders having a common goal to pursue. The one thing that we can probably all agree on, is the need for tyres and other rubber products in our society. How we then fill that need, and what future decisions we make to maximise our understanding of the possible negative implications of TWPs in the aquatic environment is of paramount importance. Our job now is to continue our research within this field and ultimately prevent excess and unnecessary pollution of the water bodies that we all depend on, in a manner that stays true to both the environment and our need for safe and reliable tyres. 

*The author is a PhD student in Environmental Biology at Roskilde University, Department of Natural Science and Environment, Denmark, with funds from Danish Environmental Analysis

References

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Europe’s tyre industry stands at a crossroads as mounting regulatory pressure, resource constraints and circular economy targets reshape the end-of-life tyre landscape. Despite Germany achieving one of the world’s highest recycling rates, an estimated 100,000 tonnes of used tyres continue to leave the country annually, undermining domestic recovery efforts. In conversation with Tyre Trends, AZuR Network Coordinator Anna-Maria Guth outlines the policy reforms, recycling technologies, retreading opportunities and cross-border collaboration needed to keep valuable raw materials in circulation and build a fully circular European tyre ecosystem.

What gaps in the traditional tyre value chain led to the establishment of the AZuR network?

In Germany, we have a very high recycling rate for end-of-life tyres. However, following a merger of certified tyre disposal companies that collect and sort tyres, it became clear that we needed to bring all stakeholders together to really make progress. The excellent response to the AZuR network shows that this is the right approach.

The European tyre industry is under increasing pressure regarding emissions, waste management and the circular economy. What policy measures are still needed to accelerate the widespread adoption of tyre recycling?

Couple of policy implementations must be achieved in order to reach this goal. The first is a strict ban on the export of ELTs and rigorous enforcement of this regulation. Secondly, clear, predictable and statutory regulations regarding the use of ELT granulate. Lastly, consistent implementation of circular economy strategies.

What role can recovered carbon black (rCB) play in reducing Europe’s dependence on primary fossil raw materials?

The pyrolysis companies in the AZuR network are making great strides in improving the quality of rCB. We are optimistic that in the foreseeable future, we will be able to produce a grade that allows the material to be incorporated into new tyres in larger quantities. That would be a major breakthrough and would create real added value as it would keep the raw materials within the circular economy.

How does AZuR distinguish between mechanical recycling, devulcanisation and pyrolysis in terms of sustainability and scalability?

Within the network, we adhere to the European waste hierarchy viz-a-viz prevention, reuse, recycle including mechanical and chemical and, finally, thermal recycling.

We are open to all technologies when it comes to processes. However, it is clear that in the interests of the circular economy, we want to minimise thermal recovery. And this also applies to pyrolysis oil provided it is not used for the production of new products but as a secondary fuel.

How close is the tyre industry to establishing tyres made with recycled materials without compromising on performance?

Some manufacturers are already field-testing tyres containing over 70 percent recycled and bio-based raw materials. The industry is very active in this area. However, we would like to see a more nuanced approach to recycled materials and bio-based materials.

Bio-based materials cannot be the solution in the medium term and the EUDR is already restricting the use of bio-based materials in Europe. Our focus must be more on recycled materials and their qualities so that raw materials can be kept in the cycle.

More than 500,000 tonnes of end-of-life tyres are generated in Germany every year. What are currently the biggest bottlenecks in the infrastructure for collection, sorting and processing?

At present, the SME sector in Germany is structured in such a way that all tyres generated can be collected, sorted and processed. Our biggest challenge is that the material is currently being exported rather than ending up with responsible companies in the circular economy. We estimate that around 100,000 tonnes are exported annually without proper regulation.

How will the network influence future EU regulations on the circular economy?

We are delighted to be engaging in growing dialogue with EU bodies, which enables us to raise the profile of the circular economy, which is dominated by small and medium-sized enterprises. Our aim is to set the right course at European level as quickly as possible so that companies can work successfully with the materials and keep as many raw materials as possible in the cycle.

Which groundbreaking technologies or business models are currently attracting the most attention?

There are quite a few, and to name just a few, we have companies in the network working on AI-driven solutions for tyre sorting as well as start-ups producing devulcanised materials for the new tyre industry or AI-assisted machines for the professional regrooving of truck tyres.

How important is cross-border cooperation in establishing a sustainable circular economy for tyres across Europe, rather than in isolated national markets?

AZuR started as a German network, but we can now safely say that we have become a European network. We have partners from Italy, the Netherlands, Austria, Ukraine, Estonia and Poland. All these countries face similar challenges as the relevant legislation is often decided at European level and we can achieve very little at national level. We can only take the big steps together in Europe.

How difficult is it to reconcile economic interests within such a diverse ecosystem?

All AZuR partners are united by a shared vision of 100 percent recycling of end-of-life tyres generated in Europe. We know that this is economically viable. However, we also know that we can only tackle the hurdles that are currently preventing us from reaching our goal by working together.

Our target of 100 percent recycling of end-of-life tyres is very realistic and, in our view, can be achieved in the short term with the right measures.

How do you respond to the market’s ongoing concerns regarding the safety, quality and performance of retreaded tyres?

The retreaders currently operating in Germany are industrial retreaders whose quality standards are in no way inferior to those of new tyre manufacturers. Real-world use shows that there are no quality limitations with retreaded tyres. When retreaded, the casings from premium manufacturers offer a quality comparable to that of the original new tyre.

Incidentally, the safety of the technology is demonstrated by retreaders of aircraft tyres as such tyres are retreaded 12 to 14 times and are highly relevant to safety. And retreading is the ideal solution for recycling as it allows the tyre to be used a second and third time as a tyre.

Why has retreading uptake in the passenger car sector remained relatively limited compared to that in the commercial vehicle sector?

One of the major challenges facing retreading in the passenger car sector is the vast variety of sizes, which makes retreading economically unviable. We are constantly seeking dialogue with vehicle manufacturers on this issue.

Furthermore, passenger car tyres are often in use for longer because they are driven less frequently, meaning fewer casings are available for retreading. However, we believe in passenger car tyre retreading, particularly given the growing share of electric vehicles, and are delighted that a retreader in Germany will be relaunching operations in this segment this year.

How important will AI, predictive analytics and sensor-based tyre management become over the next decade?

Smart tyre management is both an economic factor for haulage companies and an environmental one. We know that how a tyre is used has a significant impact on its service life. And at the top of the waste hierarchy is waste prevention. Here, both the new tyre industry and users are called upon to make optimal use of tyres so that they can remain in service for as long as possible.

What would success look like for AZuR in the next five years?

We would have reason to celebrate if we were to achieve the following key objectives in the coming years. The objectives include 40 percent market share for retreaded lorry tyres in Europe, 10 percent market share for retreaded passenger car tyres in Europe, 100 percent recycling of end-of-life tyres in Europe and clear legal regulations governing the use of recycled ELTs.   

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Epsilon Carbon has significantly expanded its manufacturing footprint with the formal activation of a new 300,000-tonne-per-annum speciality carbon plant in Vijayanagar, Karnataka. This latest addition brings the company’s aggregate production capacity in this segment to 600,000 tonnes annually, a development that elevates the firm to a leading position among domestic producers and reinforces India’s broader influence in the international speciality carbon market.

The new installation operates on a fully digitised manufacturing architecture, incorporating real-time process monitoring, automated quality controls and interconnected production systems. Such technological integration is intended to minimise operational variability, maximise throughput and provide overseas buyers with a stable and predictable supply base across multiple product categories.

Output from the Vijayanagar complex will encompass a wide array of coal-tar derivatives, including binder and impregnated pitches, refined naphthalene, anthracene and creosote oils and wash oil. These intermediates find application across a spectrum of heavy and light industries, ranging from primary aluminium and graphite electrode production to tyre compounding, pigment formulation, pharmaceutical synthesis and speciality construction materials.

Looking ahead, the company has outlined a trajectory towards further capacity enhancement, with a proposed integrated facility in Jharsuguda, Odisha, expected to push total speciality carbon output to one million tonnes per annum by the end of the decade. Meanwhile, the Karnataka plant has been configured with closed-loop water management, recycling all treated effluent internally, and derives its entire power requirement from a 17‑megawatt captive unit running on recycled process off-gases. Certifications such as Responsible Care, EcoVadis Silver and SA8000 attest to the company’s adherence to stringent safety, environmental and labour standards.

Gaurav Mathur, Chief Executive Officer, Epsilon Carbon, said, "This expansion reflects India's growing capability to become a global supplier of speciality carbon materials. With 600,000 TPA of Speciality Carbon capacity, we are strengthening supply chain resilience for both domestic industries and international customers, particularly the global aluminium sector. As the world looks to diversify supply chains, Epsilon Carbon is proud to contribute to India's emergence as a reliable, sustainable and globally competitive manufacturing hub."

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HS HYOSUNG ADVANCED MATERIALS participated in the China Composite Expo 2026 (CCE 2026), held at the National Exhibition and Convention Center in Shanghai from 1 to 3 September. This annual event stands as Asia’s largest specialised exhibition for composite materials, drawing a significant global audience.

The company has been a consistent participant in CCE since 2013, leveraging the expo to progressively reinforce its foothold in the Asian market. At this year’s showcase, the strategic focus was on its portfolio of high-performance carbon fibre products, which are increasingly recognised as essential materials for advanced sectors including energy, mobility and aerospace due to their superior tensile strength and modulus.

Central to the presentation were actual samples of TANSOME, the company’s proprietary carbon fibre brand developed through in-house technologies. The exhibit featured a diverse range of applications, from mobility components like automotive wheels, hoods and brake discs to sporting goods such as hockey sticks and pickleball rackets, as well as high-pressure vessels for hydrogen and oxygen, drones and wire cores.

In parallel, HS HYOSUNG ADVANCED MATERIALS emphasised its robust manufacturing capabilities and stable supply chain, supported by production bases in Korea, China and Vietnam. This strategy reinforces its standing as a leading global carbon fibre manufacturer. Notably, the company achieved a milestone in 2011 as the first in Korea to independently develop TANSOME, a material 4 times lighter and 10 times stronger than steel. This was followed by the 2022 launch of H3065, a T-1000-grade fibre with strength exceeding steel by over 14 times, designed for demanding aerospace applications.

Jin Dal Lim, CEO, HS HYOSUNG ADVANCED MATERIALS, said, “This exhibition is an important opportunity to further strengthen strategic partnerships with global customers and demonstrate the outstanding technological capabilities of HS HYOSUNG’s carbon fibre. We will continue to build deeper trust in the global market based on world-class product quality and stable supply capabilities.”

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Bekaert has taken a decisive step towards reshaping its operational footprint in Sardinia by securing a preliminary deal with Nuova Icom, a local engineering entity. The arrangement paves the way for the handover of the Macchiareddu premises and guarantees job continuity for the existing staff stationed there, subject to the final stipulations of the contract.

The decision stems from long-term turbulence in the tyre sector, which has steadily undermined the commercial viability of the plant's primary output. With tyre cord manufacturing struggling to remain profitable amidst evolving industry dynamics, the company concluded that a fundamental operational shift was unavoidable.

This initiative follows an extensive search for sustainable alternatives, emphasising regional employment preservation. Bekaert remains attuned to the social ramifications of the transition and pledges to engage transparently with all affected parties. The prospective ownership change is scheduled for completion by October 2026, pending regulatory clearances and the finalisation of employee consultations.

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