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

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A new bio-based cut & chip resin for the most demanding applications.

NaugaShield BIO-TR 30 is SI Group’s latest advancement in bio-based performance resins designed to significantly improve cut and chip resistance in high-severity rubber applications. With approximately 75 percent bio-based content, this innovative material delivers on sustainability targets while exceeding the performance typically associated with petroleum-derived resins, making it a strong choice for applications such as OTR tyres in mining, construction and agriculture, mining conveyor belts, rubber tracks and mill linings.

Cut and chip resistance is a complex set of material behaviours, including static mechanical strength, dynamic response under deformation and ability to withstand sharp impacts and abrasive environments. In demanding applications such as mining or agriculture, materials must tolerate repeated high-strain loading and resist the initiation and propagation of tears. NaugaShield™ BIO-TR 30 was developed precisely to meet these conditions, demonstrating notably low dynamic heat buildup and excellent tear strength – characteristics closely tied to enhanced cut and chip resistance and long-term durability under cyclical loads.

To evaluate its performance, NaugaShield BIO-TR 30 was benchmarked in an Off-road Rib Tread formulation against two widely used industry references: a gum rosin/semi-aromatic C5/C9 resin combination and a styrenated DCPD resin. All materials were tested at an equal loading of 10 phr to provide a direct and unbiased comparison. Under these conditions, the bio-based resin consistently outperformed both alternatives, offering a stronger balance of reinforcing behaviour, improved tear propagation resistance and superior resistance to thermal degradation during dynamic flexing. Further improvements were achievable by reducing the amount of free extender oil in the compound, underscoring the resin’s adaptability in formulation design and its ability to unlock even greater performance when optimised.

These laboratory indicators were corroborated through extended Coesfeld Cut & Chip testing (see chart), in which compounds were subjected to up to 3,000 cycles at 200 rpm under a 200N applied force. Formulations containing NaugaShield BIO-TR 30 exhibited substantially lower mass loss and maintained tread surface integrity more effectively than the hydrocarbon and gum rosin-based-benchmarks. The performance advantage was even more pronounced in compounds adjusted for lower free oil content, confirming that the resin can be tailored to meet the durability requirements of the most challenging operating conditions.

The strong performance of NaugaShield BIO-TR 30 in OTR tread compounds can be readily transferred to other rubber goods that encounter similar wear mechanisms. Applications such as mining belts, agricultural and construction tracks or mill linings benefit from the resin’s ability to reinforce the rubber matrix, reduce crack growth under repeated impact and maintain structural cohesion under high-strain deformation. This versatility allows manufacturers to integrate a 75 percent bio-based resin that supports sustainability by reducing fossil-based content and helping end products last longer while maintaining – and often improving – operational performance across multiple product lines.

NaugaShield BIO-TR 30 is currently available in commercial quantities, enabling compounders and manufacturers to move directly from laboratory evaluation to pilot- and production-scale trials.

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Kuraray Co., Ltd. marked its 100th anniversary on 24 June 2026, with a commemorative ceremony at the Tokyo International Forum. The company live-streamed the event to its domestic and overseas locations, enabling employees worldwide to join the celebration simultaneously and strengthening the Group's collective spirit.

The speciality chemical company expressed deep appreciation to its stakeholders and predecessors for their enduring support throughout the century. Leaders also reaffirmed the organisation's determination to pursue new challenges collaboratively as it embarks on its next hundred years.

Hitoshi Kawahara, President, Kuraray Co., Ltd.

President Hitoshi Kawahara called for uniting values across diverse countries, regions, languages and cultures during this pivotal moment. He advocated for realising ‘One Kuraray’ by actively connecting people, technologies and knowledge beyond conventional organisational and business boundaries to co-create fresh value.

Kuraray originated in 1926 in Kurashiki, Okayama Prefecture, with the commercial production of synthetic rayon. Over the past century, the company built its reputation on distinctive technologies, including PVA fiber, PVOH resin, CLARINO man-made leather and EVAL EVOH resin, guided by its mission to achieve what no other company can for people and the planet. Today, Kuraray operates across 32 countries and regions. The company now views its centennial as a launching point for tackling social challenges through innovation and for unlocking new possibilities in the years ahead.

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Cabot Corporation has once again achieved the top-tier platinum designation from EcoVadis, maintaining this elite status for six consecutive years. This accomplishment secures the company’s place among the global elite, as only one percent of all businesses scrutinised by the rating agency receive this highest mark. The outcome reflects the firm's sustained emphasis on driving tangible environmental and social advancements while upholding rigorous disclosure standards across its operational network.

The assessment framework employed by EcoVadis examines more than 150,000 entities worldwide, spanning numerous sectors and geographies, with evaluations rooted in established sustainability benchmarks. Cabot registered its most significant annual performance jump this cycle, with a five-point increase in its cumulative score, driven largely by enhanced results in the ethical conduct segment. Additionally, the company retained its exceptional standing in both environmental stewardship and workforce rights, securing the maximum possible recognition in those two critical areas.

With EcoVadis consistently tightening its evaluation parameters to mirror emerging global norms, Cabot has responded by intensifying its own internal sustainability measures. The organisation has concentrated on elevating operational effectiveness and data visibility, ensuring its practices remain responsive to the increasingly stringent expectations of stakeholders and rating bodies alike.

Underpinning this trajectory is a deeply ingrained organisational culture focused on iterative refinement and long-term value creation. By persistently elevating its sustainability agenda, Cabot reinforces its reputation as a proactive industry participant, dedicated to aligning corporate performance with broader societal and environmental objectives.

Jennifer Chittick, Senior Vice President, Safety, Health and Environment (SH&E) and Government Affairs; Chief Sustainability Officer, said, “We are encouraged by this year’s EcoVadis results, which reflect meaningful progress across our sustainability programme and our largest year-over-year score increase to date. These results demonstrate how greater transparency, stronger cross-functional collaboration and disciplined execution are helping us strengthen how we operate while advancing progress toward our 2030 sustainability goals.”

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Nokian Tyres has secured a position among TIME Magazine’s World’s Most Sustainable Companies for 2026, claiming the 100th spot on a prestigious roster of 750 global enterprises. The annual compilation, produced in partnership with the research firm Statista, recognises organisations demonstrating exceptional environmental and social performance after a comprehensive evaluation of thousands of candidates worldwide.

The selection process weighed verified sustainability credentials, including active participation in the UN Global Compact and Science Based Targets initiative-approved emission reduction goals. Assessment also incorporated third-party ratings from entities like CDP and MSCI, alongside rigorous scrutiny of each company’s transparent operations, ethical governance and overall commitment to environmental stewardship and social responsibility, ultimately distinguishing Nokian Tyres for its holistic approach to corporate accountability.

Paolo Pompei, President and CEO, Nokian Tyres, said, “This is a great acknowledgment of our long-term sustainability work and motivates us to keep improving. We want to enable drivers to make more sustainable tyre choices without compromising on performance. Renewable and recycled materials and lower rolling resistance help cut tyre lifecycle emissions, while rigorously tested tyres improve grip and safety, especially in demanding weather conditions. Proactive sustainability measures also benefit our customers: responsible sourcing reduces risks, and innovative, high-performing tyres with lower environmental footprint make it possible for our customers to offer higher-value solutions to their own clients.”

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