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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The Rubber Board of India has launched a series of educational videos as part of the iSPEED (INROAD Skilling and Production Efficiency Enhancement Drive) programme, an INR 1.50-billion initiative aimed at enhancing skill development, quality improvement and infrastructure building within the natural rubber sector. This launch comes as the plantation activities under the larger Project INROAD (Indian Natural Rubber Operations for Assisted Development) in Northeast India approach completion, shifting focus towards productivity and quality enhancement through modern training and facilities.

The newly released video series targets nearly 300,000 rubber growers in the region, covering five essential processing areas: Rubber Tapping, Rain Guarding, Grading, Rubber Sheet Making and Scientific Smokehouses. To ensure broad accessibility, the modules have been produced in Assamese, Bengali, Hindi and Malayalam, enabling effective communication with diverse stakeholders across the natural rubber ecosystem.

The official release of the videos was conducted by Executive Director M Vasanthagesan, alongside Rubber Production Commissioner Dr Siju T Nair, other senior Board officials and representatives from the Indian tyre industry. Developed over the past year with technical assistance from the Rubber Board and the Rubber Research Institute of India, the educational content combines animation with real-life field demonstrations to simplify complex scientific practices for easy adoption.

Project INROAD represents a unique collaboration between the Indian tyre industry and the Rubber Board, with support from Apollo Tyres, CEAT, JK Tyre and MRF. Over the last five years, this partnership has facilitated new rubber plantations across approximately 180,000 hectares in 113 districts of Northeast India, establishing it as the country’s largest plantation development programme of its kind.

Mohan Kurian, Chairman, INROAD Project, said, "Skill development and adoption of scientific practices are essential for improving both productivity and quality in the natural rubber sector. These multilingual videos will serve as an effective training resource for growers and complement the Rubber Board's ongoing extension efforts across the country.”

Sanjiv Saxena, Convener, ATMA Supply Chain & Resources (SCR) Group, said, "The objective of the participating member companies under INROAD is to ensure that rubber growers benefit the most from a stronger natural rubber value chain. By improving productivity and quality, we aim to help farmers realise better returns while strengthening the sustainability of the entire ecosystem."

Muraligopal, who played a key role in coordinating the development of the videos, said, "These videos are the result of close collaboration with the Rubber Board, RRII and field teams across the Northeast. Their guidance and support helped us develop practical, farmer-friendly training modules based on scientific best practices."

Zeon Corporation has finalised the construction of a new bench-scale facility at its Tokuyama Plant in Shunan City, Yamaguchi Prefecture, dedicated to advancing the efficient production of butadiene from sustainable ethanol sources. The project, which broke ground in July 2025, represents a strategic move to establish a naphtha-independent raw material supply chain, thereby bolstering both corporate sustainability and the broader transition towards a carbon-neutral society. The facility is slated to commence full-scale operations in January 2027, with the ultimate goal of achieving commercial viability by 2034.

A commemorative ceremony took place at the plant site on 31 July 2026, drawing a total of 46 attendees. The gathering included official representatives from Japan’s Ministry of Economy, Trade and Industry (METI), the New Energy and Industrial Technology Development Organization (NEDO) and local governmental bodies from Yamaguchi Prefecture and Shunan City. Also present were delegates from the Yokohama Rubber Company, the construction contractor and various affiliated firms, alongside Zeon’s leadership, including Akira Honma, the Corporate Officer and Tokuyama Plant Manager.

This initiative forms one half of a dual-themed research and development programme undertaken in partnership with Yokohama Rubber, under the auspices of NEDO’s Green Innovation Fund. The collaborative effort is focused on the social implementation of technologies for synthesising both butadiene and isoprene from renewable biological materials by the 2030s. As part of this process, Zeon is set to produce a prototype polybutadiene rubber using the output from the new bench-scale facility, while Yokohama Rubber will subsequently manufacture test tyres from this material and conduct performance evaluations on test tracks.

Both companies have outlined a clear roadmap, intending to finalise the core technology for societal deployment by 2030 through the operation of a larger pilot plant, with full-scale commercialisation targeted for 2034. The bench-scale facility is a critical precursor in this phased approach, providing essential data for the scale-up process.

The broader project encompasses two selected NEDO themes, both subsidised through the Green Innovation Fund. The first involves the highly efficient synthesis of butadiene from ethanol, with technical cooperation from the National Institute of Advanced Industrial Science and Technology. The second focuses on biotechnological pathways to directly produce butadiene and isoprene from plant-based materials, involving partnerships with the Institute of Science Tokyo and RIKEN. Both tracks aim to supplement synthetic rubber feedstocks and support closed-loop recycling, aligning with Japan’s 2050 net-zero emissions goal by fostering long-term industrial innovation.

The Association of Natural Rubber Producing Countries (ANRPC) has released its Monthly Natural Rubber Statistical Report for June 2026, a month defined by price resilience amid conflicting market forces. The provisional reopening of the Strait of Hormuz triggered a sharp 20.29 percent drop in Brent crude oil prices to USD 85.40 per barrel. However, this bearish signal was counterbalanced by persistent supply constraints from El Niño-related weather disruptions across major producing regions.

Physical rubber prices posted broad-based gains across most grades. SMR-20 rose 1.39 percent to USD 2.32 per kilogramme, while STR-20 gained 2.61 percent to USD 2.55 per kilogramme. RSS-3 and RSS-4 advanced 4.98 percent and 5.88 percent to USD 3.09 and USD 2.84 per kilogramme, respectively, though latex eased 1.44 percent to USD 1.94 per kilogramme. On the trade front, China's imports surged 7.14 percent month-on-month, while India and Viet Nam declined. Export growth was recorded for Cambodia, Viet Nam and Indonesia, though Thai shipments contracted.

Global production for 2026 is projected at 15.310 million tonnes, up 2.3 percent from 2025, driven by gains in Thailand, China, India and Malaysia. However, June output fell 3.7 percent year-on-year to 1.207 million tonnes due to seasonal wintering and El Niño-related weather disruptions. Malaysia, Indonesia and Cambodia have introduced new incentive and governance measures to strengthen their sectors. Global consumption is forecast to grow 0.7 percent to 15.411 million tonnes in 2026, with June consumption rising 3.3 percent to 1.300 million tonnes, led by China and India amid steady tyre and EV-related demand.

Currency markets saw the Malaysian ringgit trade between RM3.96 and RM4.08 against the US dollar, while the Thai baht ranged from 32.56 to 33.24. In futures trading, the SHFE September 2026 contract averaged 17,580.68 CNY per tonne, down 0.45 percent month-on-month, while the SGX September contract averaged USD 2.24 per kilogramme, up 1.75 percent, with both reflecting tightening supply and firm downstream demand.

Pyrum Innovations AG has finalised long-term supply and offtake agreements with Pirelli, reinforcing the tyre manufacturer’s European Tyre-to-Tyre initiative. The deal secures Pirelli’s purchase of Pyrum’s ThermoTireBlack (TTB) for use in its European production facilities, while Pirelli will provide Pyrum with end-of-life tyres from designated German sources.

These contracts simultaneously bolster Pyrum’s feedstock security and guarantee an industrial outlet for its recycled materials, covering both raw material procurement and product commercialisation. Through its proprietary thermolysis process, Pyrum transforms scrap tyres into ThermoTireBlack, which can substitute fossil-based carbon black, and ThermoTireOil (TTO), destined for chemical industry use. The partnership offers further validation of Pyrum’s technology within a certified European value chain involving tyre, chemical and synthetic-rubber leaders.

Pyrum also supports the broader Tyre-to-Tyre project, initiated by Pirelli with BASF and Synthos, which reintroduces secondary materials from used tyres and production waste into new tyre manufacturing via an ISCC PLUS-certified, traceable system.

Pascal Klein, CEO, Pyrum Innovations AG, said, “Signing these long-term agreements with Pirelli is an important commercial and strategic milestone for Pyrum. The coöperation secures both the supply of end-of-life tyres and an industrial outlet for our TTB. It confirms that our technology and products meet the requirements of one of the world’s leading tyre manufacturers and can contribute to the establishment of scalable circular value chains in Europe.”