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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Birla Carbon Spain has been awarded a EUR 2 million grant by the Society for Regional Development of Cantabria S.A. (SODERCAN), a public entity of the Government of Cantabria, to advance an energy autonomy initiative at its Cantabria plant. The funding announcement was made in late February during a visit attended by María José Sáenz de Buruaga, President of Cantabria; Eduardo Arasti, Minister of Industry, Employment, Innovation, and Trade of Cantabria and Ángel Pedraja, CEO of SODERCAN. The grant forms part of a broader investment project by Birla Carbon Spain aimed at strengthening energy self-sufficiency at the facility.

The funding will support the installation of a 4 MW back-pressure steam turbine at the Cantabria unit, enabling it to generate electricity and steam internally for operations. When completed, the project is expected to reduce CO2 emissions annually while also decreasing reliance on water from the Miera River for cooling purposes and reducing process water discharge. Beyond these environmental benefits, the investment will help safeguard nearly 200 direct and indirect jobs associated with the facility, reinforcing the company's commitment to both sustainability and regional economic stability.

During the visit, President María José Sáenz de Buruaga was briefed on the technical and environmental aspects of the project and described it as a collective success. She recognised Birla Carbon Spain's strategic role in the regional industrial ecosystem and its position as a benchmark for innovation in Europe. The initiative represents a significant step towards sustainable manufacturing practices while demonstrating the company's dedication to long-term operational viability and environmental stewardship in Cantabria.

Dale Clark, Chief Manufacturing Officer, Americas & EMEA, Birla Carbon, said, “We were honoured to welcome the President of Cantabria, the Minister of Employment, Innovation and Trade of Cantabria and the CEO of SODERCAN to our Cantabria plant. Their support reflects the strategic importance of our operations to the region and the industries we serve with our carbon black solutions. The steam turbine will be key in helping the plant achieve energy autonomy, reducing our carbon footprint and strengthening long-term operational resilience. At Birla Carbon, we also remain continuously focused on improving energy efficiency, reducing water consumption and advancing sustainable manufacturing practices across our global operations.”

María José Sáenz de Buruaga, President of Cantabria, said, “With this contribution, not only does Birla Carbon win, but Cantabria wins too, because we are making decisive progress in the transformation of our production model and in our commitment to industrialisation.”

Flexsys, a global leader in advanced tyre additives and material-science solutions, has been honoured with the Chemical and Compounding Innovation of the Year Award at the Tire Technology International Awards for Innovation and Excellence. This recognition celebrates the company’s progress in creating a novel alternative to 6PPD for tyre manufacturing.

Driven by a significant challenge within the tyre industry, Flexsys’s dedicated research and development team, alongside respected federal and independent laboratories, pursued the creation of a next-generation replacement for 6PPD. Their investigation spanned hundreds of molecules from various chemical families, ultimately identifying several promising candidates that satisfy the stringent criteria for both tyre efficacy and environmental safety. Extensive laboratory testing, conducted both internally and by external parties, has confirmed that one of these candidates delivers robust antidegradant qualities while presenting a favourable toxicological profile. Significantly, this effective molecule is not a PPD chemical. Currently, performance trials are in progress with selected industrial collaborators, with further information regarding the specific molecule anticipated later this year.

The award itself is determined by a completely autonomous international jury composed of journalists and industry specialists. It is coordinated by Tire Technology International magazine, a publication owned by UKi Media & Events, which also organises the renowned Tire Technology Expo.

Neil Smith, Chief Technology and Sustainability Officer, said, “We are honoured to receive this industry recognition for our work, which reflects our commitment to delivering solutions that meet demanding performance requirements while advancing environmental responsibility. I’m incredibly proud of the Flexsys R&D team whose dedication and scientific rigor has allowed us to achieve this recognition. We believe collaboration across the tyre and materials ecosystem is essential to developing durable, scalable solutions for the industry and look forward to continuing this journey together.”

Matt Ross, Editor-In-Chief, Tire Technology International magazine, said, “The Tire Technology International Awards for Innovation and Excellence are recognised as the industry’s top accolades and aim to celebrate the best new technologies and innovations from all over the world. On behalf of all of the judges, we extend our congratulation to the Flexsys team on this win and their work to find a replacement for 6PPD in tyres.”

Pyrum Innovations AG has announced an immediate update to the nomenclature of its recycled material outputs as part of a strategic effort to reinforce its brand identity and underscore the distinctiveness of its offerings. The company’s thermolysis oil, formerly referred to as recycled oil, will now be designated TTO (ThermoTireOil). Similarly, what was previously known as recovered Carbon Black (rCB) will adopt the new name TTB (ThermoTireBlack).

This decision stems from inconsistencies observed across the broader market for recycled commodities. Materials sold under generic labels such as rCB or pyrolysis oil often vary significantly in composition, largely because they may contain residual additives or lack standardisation. In the case of rCB, for instance, the presence of inorganic elements from tyres can lead to blends that are unsuitable for certain high-performance applications. Pyrum’s output, by contrast, is produced through its patented thermolysis technology, which yields materials with a consistent and well-defined makeup. The new names are intended to reflect this precision and set them apart from less uniform alternatives.

The underlying production process remains centred on breaking down end-of-life tyres into their constituent elements. TTB has already entered series manufacturing in the tyre industry and is gaining recognition for use in products such as conveyor belts, seals, and protective coatings. TTO, meanwhile, functions as a renewable input for polymers used in clothing, automotive components and food-safe packaging.

Rollout of the new terminology begins at once and will be phased into all technical records, official certifications and customer communications. Although the labelling is new, the formulations and quality levels of the products themselves are unchanged.

Pascal Klein, CEO, Pyrum Innovations AG, said, “Our products are the result of years of development and intensive research. With the new designations TTO and TTB for our oil and our rCB, we make it clear that these are unique materials obtained from our unique thermolysis process.”

KRAIBURG TPE has earned gold medal from EcoVadis for the second consecutive year. This recognition reflects the performance of the company’s entire global operations, which collectively achieved this distinguished honour. The company posted new peak scores across all four evaluation categories, which include environmental impact, labour and human rights, ethical conduct and sustainable sourcing. Ranking in the 98th percentile, KRAIBURG TPE now stands among the top two percent of all companies rated by EcoVadis globally, reinforcing its status as a frontrunner in responsible corporate practices.

Within the plastics sector, sustainability has evolved into a fundamental driver of success. Growing public attention now extends beyond isolated topics, calling instead for businesses to offer clear and reliable sustainability reporting. Measurable indicators that track advancements and allow for objective comparisons across industry peers have thus become indispensable.

Having evaluated over 150,000 businesses, EcoVadis has cemented its role as one of the most trusted frameworks for assessing corporate sustainability. The benchmarks applied by the Paris-based organization across its categories are both rigorous and comprehensive. Given this demanding standard, KRAIBURG TPE’s 2022 achievement of a silver award in its debut year was particularly meaningful.

In 2025, the company reached a new milestone by receiving its first gold medal covering all global facilities, a testament to inter-site collaboration and the dedication of its entire workforce. This distinction was reaffirmed during the scheduled reassessment in January 2026, accompanied by even higher marks in every category. Such ongoing improvement demonstrates the company’s steadfast commitment to advancing its sustainability objectives consistently across international operations.

Oliver Zintner, CEO, KRAIBURG TPE, said, “For us, this second Gold Award is confirmation in many respects of the extraordinary achievements we have made in the field of sustainability in the past years. On the one hand, it demonstrates how strong our position is in international comparison. But above all, the award emphasises how continuously and persistently we pursue our sustainability goals in all categories. Results like that are not at all a matter of course in our competitive environment. They only become possible because our colleagues at all sites worldwide are closely working together in a partnership-based manner.”

Michael Pollmann, Sales & Marketing Director EMEA, said, “In addition to product quality, price and delivery reliability, sustainability criteria are a more and more important factor for our customers’ purchase decisions. The EcoVadis award represents the consistency and transparency with which we implement our sustainability promises. It is a relevant strategic competitive factor and is gaining in importance, particularly in view of increasing legal requirements in fields such as supply chain assessment.”