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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The Rubber Board of India has announced a temporary engagement for a young professional within its Market Promotion Division, located at the RRII campus in Puthuppally, Kottayam. The selected individual will assist with division activities and promote ‘mRube’, the electronic trading platform for natural rubber.

Candidates must hold an MBA in Marketing or Agri Business Management with computer knowledge, while skills in digital marketing, sales or market research and proficiency in English and Hindi are preferred. Applicants aged up to 30 years as of 1 May 2026, will be considered for the one-year role, which offers a consolidated monthly pay of INR 25,000.

Interested individuals should send their applications to the Deputy Director (Marketing) at the Central Laboratory Building, RRII, Rubber Board PO, Kottayam – 686009 by 19 May 2026. Shortlisted names will appear on the Rubber Board’s website with interview details, as no separate communication will be sent.

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Bekaert has officially finalised its acquisition of Bridgestone’s tyre reinforcement operations in China and Thailand, after securing all necessary regulatory approvals and meeting standard closing conditions. The deal, now fully completed, marks a significant step in the Belgian company’s expansion strategy.

The transaction brings under Bekaert’s control two production facilities: Bridgestone (Shenyang) Steel Cord Co., Ltd. in China and Bridgestone Metalfa (Thailand) Co., Ltd. in Thailand. These plants specialise in manufacturing high-quality tyre cord products exclusively for Bridgestone tyres, and they will continue to supply Bridgestone under the new ownership, further deepening the longstanding partnership between the two firms.

Financially, the acquisition is expected to add roughly EUR 80 million to Bekaert’s annual consolidated sales. The EUR 60 million cash consideration for the deal was funded from the company’s available cash reserves.

Curd Vandekerckhove, CEO Rubber Reinforcement, said, “With the completion of this acquisition within our Rubber Reinforcement division, we are pleased to officially welcome the plant teams in China and Thailand to Bekaert. Our immediate focus is on a smooth transition and operational continuity while continuing to serve Bridgestone as a key strategic partner. The completion of the acquisition further strengthens the position of Bekaert in the tyre cord market, expands the global manufacturing footprint and deepens our longstanding partnership with Bridgestone. A long-term supply agreement ensures continued delivery of high-quality tyre reinforcement within a trusted supplier model.”

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The Association of Natural Rubber Producing Countries (ANRPC) has released its Monthly NR Statistical Report for March 2026, revealing a market that turned external pressures into clear price gains. While February had hinted at shifting dynamics, March provided proof of the industry’s core strength, with prices rising across all major grades and trading hubs despite an unusually challenging global environment. A 3.4 percent drop in monthly output and a dramatic 42.51 percent spike in Brent crude prices allowed natural rubber to advance rather than retreat.

Benchmark grades recorded widespread increases. In Kuala Lumpur, SMR-20 reached an average of USD 2.04 per kilogramme, while Bangkok saw STR-20 climb to USD 2.20 and RSS-3 jump to USD 2.56 per kilogramme. Kottayam’s RSS-4 averaged USD 2.35, and centrifuged latex in Kuala Lumpur rose sharply to USD 1.72 per kilogramme. Futures markets echoed the trend, with Shanghai’s May contract averaging CNY 16,662 per tonne and Singapore’s June contract closing at USD 1.95 per kilogramme.

The supply situation tightened considerably. Global March production is forecast at 786,000 tonnes, with Thailand’s output falling to 164,000 tonnes as southern growing regions endured temperatures of 42 to 43 degrees Celsius and rainfall up to 69 percent below normal levels. These punishing conditions sent a clear message that the market can absorb demand without chaotic price swings, a sign of a maturing commodity sector.

Demand told a similarly positive story. China’s natural rubber consumption surged from 446,000 tonnes in February to 610,000 tonnes in March, supported by a manufacturing PMI of 50.4, a 74.4 percent monthly rise in vehicle output, and a 130 percent annual leap in new energy vehicle exports. Chinese imports jumped 39.03 percent month-on-month to 629,800 tonnes, while Vietnam, Malaysia and Thailand boosted exports by 47.34 percent, 13.73 percent and 8.3 percent, respectively.

The oil market further strengthened natural rubber’s competitive edge. With Brent crude averaging over USD 101 per barrel and peaking at USD 126.69 on 31 March, synthetic rubber became significantly less cost-effective, giving tyre makers a strong incentive to favour natural rubber. Policy moves also bolstered confidence, including Malaysia’s replanting aid increase to RM 20,000 per hectare and a new Indonesian research partnership on high-yield rubber tree genetics.

Looking ahead to the second quarter, the market enters the seasonal low-yield period with firming demand. New energy vehicle growth across Asia, an elevated oil floor, replanting investments and tightening supply all point to constructive pricing. Risks like trade disputes, weather extremes and geopolitical tensions remain, but March data shows an industry turning uncertainty into opportunity.

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Sailun Group, a prominent player in the global tyre industry, has taken a leading role in advancing sustainable natural rubber practices. As a core raw material for tyre manufacturing, natural rubber requires ecological protection and a stable supply, both essential for the sector’s high-quality development. In 2025, the company, as a member of the Global Platform for Sustainable Natural Rubber (GPSNR), initiated a project focused on sustainable livelihoods and ecological education for smallholders in eastern Thailand under the GPSNR Shared Investment Mechanism.

This initiative unites strategic partners across the natural rubber value chain, including the Rubber Authority of Thailand’s Rayong office and Save the Children Thailand. Through multi-stakeholder collaboration, the project aims to foster a more sustainable natural rubber ecosystem. Recently, Sailun Group invited GPSNR Chief Executive Officer Stefano Savi and his delegation to Thailand for a field visit to review the project’s interim achievements, reflecting the company’s ‘eco+’ sustainability strategy and its active role in global governance for sustainable natural rubber.

Eastern Thailand’s natural rubber industry supports millions of smallholder households, and the project directly addresses the needs of 500 such farmers. Targeted training programmes have been delivered on environmentally responsible tapping techniques and regulatory compliance, including guidance on the European Union Deforestation Regulation. An innovative consultation network comprising one central hub, eight fixed stations and five mobile units now provides ongoing support on policy interpretation and practical problem-solving.

A structured and replicable knowledge system has been developed, including training materials on low-impact tapping and compliance. Special emphasis is placed on encouraging women and young people to participate, promoting intergenerational knowledge transfer. During the visit, the delegation held technical discussions with Rayong officials on sustainable tapping and rubber tree management, inspected standardised production lines and logistics facilities and reviewed the consultation stations, praising the integrated technology, services and compliance support model.

To address challenges such as improper tapping and soil degradation, five GPSNR demonstration plots have been established. Smallholders receive free organic soil improvement packages and professional tapping tools, alongside systematic training on sustainable soil management. The delegation observed pH monitoring systems and noted improvements including reduced soil acidity and better growing conditions. Direct engagement with farmers provided insights into practical challenges, and the delegation commended the project’s pragmatic approach to strengthening ecological cultivation and long-term productivity.

Beyond livelihood improvements, the project prioritises education through infrastructure upgrades at three schools attended by rubber farmers’ children. In partnership with Save the Children Thailand, ecological education corners with tailored curricula and drawing competitions have been set up. A scholarship programme supports disadvantaged students. The delegation visited Rayong Guanghua School and Banraijandee School, reviewing improvements and awarding scholarships, while discussions explored future collaboration on integrating sustainable natural rubber development with children’s ecological education.

Since implementation began, notable interim results have been achieved across multiple rubber‑producing communities. Smallholders’ sustainable production capabilities have significantly improved, while more children engage with nature and understand the natural rubber industry. This dual‑impact model of economic empowerment and environmental stewardship guides future efforts. Sailun Group will continue leveraging its industry leadership and the GPSNR platform to deepen collaboration with partners, research institutions and non‑profits, contributing to biodiversity conservation, supply chain resilience and high‑quality sustainable development across the global tyre and natural rubber industries.

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