TYRE DEBRIS IN AQUATIC ENVIRONMENT: THE NEW BLACK?

TYRE DEBRIS IN AQUATIC  ENVIRONMENT: THE NEW BLACK?

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

 

Louise Lynn Halle is a PhD student in Environmental Biology
at Roskilde University, Department of Natural Science and Environment, Denmark,
with funds from Danish Environmental Analysis

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

Mysid after ingestion of TWPs (Private photo)

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

1.        Thompson. Identification of vehicle tyre rubber in roadway dust. Am Ind Hyg Assoc 27, 488–495 (1966).

2.        Lassen, C., Hansen, S.F., Magnusson, K., Norén, F., Hartmann, N.I.B., Jensen, P.R., Nielsen, T.G., Brinch, A. Microplastics - Occurence, effects and sources of releases to the environment in Denmark. (Danish EPA, 2015).

3.        Boucher, J. & Friot, D. Primary microplastics in the oceans: A global evaluation of sources. (2017). doi:10.2305/IUCN.CH.2017.01.en

4.        Kole, P. J., Löhr, A. J., Belleghem, F. G. A. J. Van & Ragas, A. M. J. Wear and tear of tyres : A stealthy source of microplastics in the environment. Int. J. Environ. Res. Public Health 14, 1265 (2017).

5.        Kolomijeca, A., Parrot, J., Khan, H., Shires, K., Clarence, S, Sullivan, C., Chibwe, L., Sinton, D., Rochman, C. Increased Temperature and Turbulence Alter the Effects of Leachates from Tyre Particles on Fathead Minnow (Pimephales promelas). Environ. Sci. Technol. 54, 1750–1759 (2020).

6.        Unice, K. M., Panko, J.M.., Chu, J. & Kreider, M. L. Measurement of airborne concentrations of tyre and road wear particles in urban and rural areas of France, Japan, and the United States. Atmos. Environ. 72, 192–199 (2013).

7.        Kreider, M. L., Unice, K. M. & Panko, J. M. Human health risk assessment of Tyre and Road Wear Particles (TRWP) in air. Hum. Ecol. Risk Assess. 0, 1–19 (2019).

8.        Unice, K. M. et al. Characterizing export of land-based microplastics to the estuary - Part I: Application of integrated geospatial microplastic transport models to assess tyre and road wear particles in the Seine watershed. Sci. Total Environ. 646, 1639–1649 (2019).

9.        Unice, K. M. et al. Characterizing export of land-based microplastics to the estuary - Part II: Sensitivity analysis of an integrated geospatial microplastic transport modeling assessment of tyre and road wear particles. Sci. Total Environ. 646, 1650–1659 (2019).

10.      Wik, A. & Dave, G. Occurrence and effects of tyre wear particles in the environment - A critical review and an initial risk assessment. Environ. Pollut. 157, 1–11 (2009).

11.      Redondo-Hasselerharm, P. E., de Ruijter, V. N., Mintenig, S. M., Verschoor, A. & Koelmans, A. A. Ingestion and chronic effects of car tyre tread particles on freshwater benthic macroinvertebrates. Environ. Sci. Technol. acs.est.8b05035 (2018). doi:10.1021/acs.est.8b05035

12.      Khan, F. R., Halle, L. L. & Palmqvist, A. Acute and long-term toxicity of micronized car tyre wear particles to Hyalella azteca. Aquat. Toxicol. 213, 105216 (2019).

13.      Halle, L. L., Palmqvist, A., Kampmann, K. & Khan, F. R. Ecotoxicology of micronized tyre rubber : Past , present and future considerations. Sci. Total Environ. 135694 (2019). doi:10.1016/j.scitotenv.2019.135694

14.      LaPlaca, S. B. & van den Hurk, P. Toxicological effects of micronized tyre crumb rubber on mummichog (Fundulus heteroclitus) and fathead minnow (Pimephales promelas). Ecotoxicology (2020). doi:10.1007/s10646-020-02210-7

15.      Kellough, R. M. The effects of scrap automobile tyres in water. (1991).

16.      Day, K. E., Holtze, K. E., Metcalfe-Smith, J. L., Bishop, C. T. & Dutka, B. J. Toxicity of leachate from automobile tyres to aquatic biota. Chemosphere 27, 665–675 (1993).

17.      Abernethy, S. The acute lethality to rainbow trout of water contaminated by an automobile tyre. (1994).

18.      Hartwell, S. I., Jordahl, D. M., Dawson, C. E. O. & Ives, A. S. Toxicity of scrap tyre leachates in estuarine salinities: Are tyres acceptable for artificial reefs? Trans. Am. Fish. Soc. 127, 796–806 (1998).

19.      Hartwell, S. I., Jordahl, D. M. & Dawson, C. E. O. The effect of salinity on tyre leachate toxicity. Water. Air. Soil Pollut. 121, 119–131 (2000).

20.      Gunasekara, A. S., Donovan, J. A. & Xing, B. Ground discarded tyres remove naphthalene, toluene, and mercury from water. Chemosphere 41, 1155–1160 (2000).

21.      Edil, T. B., Park, J. K. & Kim, J. Y. Effectiveness of scrap tyre chips as sorptive drainage material. J. Environ. Eng. 130, 824–831 (2004).

22.      Lisi, R. D., Park, J. K. & Stier, J. C. Mitigating nutrient leaching with a sub-surface drainage layer of granulated tyres. Waste Manag. 24, 831–839 (2004).

23.      Aydilek, A. H., Madden, E. T. & Demirkan, M. M. Field evaluation of a leachate collection system constructed with scrap tyres. J. Geotech. Geoenvironmental Eng. 132, 990–1000 (2006).

24.      Alamo-Nole, L. A., Perales-Perez, O. & Roman, F. R. Use of recycled tyres crumb rubber to remove organic contaminants from aqueous and gaseous phases. Desalin. Water Treat. 49, 296–306 (2012).

25.      Alamo-Nole, L. A., Perales-Perez, O. & Roman-Velazquez, F. R. Sorption study of toluene and xylene in aqueous solutions by recycled tyres crumb rubber. J. Hazard. Mater. 185, 107–111 (2011).

26.      Parker-Jurd, F. N. F. Napper, I. E. Abbott, G. D. Hann, S. Wright, S. L. Thompson, R. C. Investigating the sources and pathways of synthetic fibre and vehicle tyre wear contamination into the marine environment (project code ME5435). (2019).

27.      Kumata, H., Yamada, J., Masuda, K., Takada, H., Sato, Y., Sakurai, T., Fujiwara, K. Benzothiazolamines as tyre-derived molecular markers: Sorptive behavior in street runoff and application to source apportioning. Environ. Sci. Technol. 36, 702–708 (2002).

28.      Klöckner, P., Reemtsmp, T., Eisentraut, P., Braun, U., Ruhl, A.S., Wagner, S. Tyre and road wear particles in road environment – Quantification and assessment of particle dynamics by Zn determination after density separation. Chemosphere 222, 714–721 (2019).

ANRPC Publishes Monthly NR Statistical Report For August 2026

ANRPC Publishes Monthly NR Statistical Report For August 2026

The Association of Natural Rubber Producing Countries (ANRPC) published its Monthly Natural Rubber Statistical Report for August 2026, noting firmer prices in several markets. Supply constraints, stable downstream demand and persistent geopolitical and macroeconomic uncertainty shaped the month. Renewed conflict and disruptions to major shipping routes added further pressure.

Physical prices for major grades moved in different directions. SMR-20 in Kuala Lumpur averaged USD 2.31 per kg, up 4.25 percent from July, while STR-20 in Bangkok rose 1.40 percent to USD 2.39 per kg. RSS-3 dropped 4.18 percent to USD 2.80 per kg, but RSS-4 in Kottayam gained 0.57 percent to USD 2.92 per kg. Latex-in-bulk fell 4.73 percent to USD 1.73 per kg. Brent crude averaged USD 91.08 per barrel, driven by concerns over possible restrictions on oil shipments through the Strait of Hormuz and wider Middle East instability, which raised energy supply risks and strengthened the oil market risk premium.

On trade, China's imports climbed 3.39 percent month-on-month, while India fell 10.18 percent and Malaysia dropped 8.24 percent; Viet Nam rose 5.08 percent. Exports advanced 5.63 percent in Viet Nam but declined in Thailand (-5.24 percent), Indonesia (-5.36 percent), Malaysia (-1.48 percent) and Cambodia (-1.88 percent).

Global production is projected to rise 0.6 percent to 15.039 million tons in 2026 from 14.952 million tonnes in 2025, after revisions to Thailand's 2025 output and updated 2026 estimates for Thailand, Malaysia and Indonesia. Weather, including erratic rainfall and drier Southeast Asian conditions, affected output. August 2026 production was estimated at 1.396 million tonnes, down 4.51 percent from 1.462 million tonnes a year earlier. Demand is forecast to grow 0.4 percent to 15.356 million tonnes in 2026 from 15.301 million tonnes, with the largest consumption gains expected in China, Malaysia and Cambodia. Prospects depend on vehicle sales, tyre production, shipping conditions and weather-related supply disruptions, while steady EV-linked demand supported modest growth led by China and India. The ringgit traded between RM4.02 per USD and RM4.09 per USD, and the baht between 32.68 and 33.34. The SHFE January 2027 contract averaged 18,109 CNY per tonne, up 7.78 percent month-on-month, while the SGX November 2026 contract averaged USD 2.24 per kg, up 4.32 percent.

HS HYOSUNG To Expand Mexico Investments From 2027 Under New State Agreement

HS HYOSUNG To Expand Mexico Investments From 2027 Under New State Agreement

HS HYOSUNG has formalised a memorandum of understanding (MoU) with the State Government of San Luis Potosí, with the signing taking place at the World Trade Center Mexico City. The event formed part of the Korea-Mexico Business Forum, held alongside the Korean economic delegation's visit to Mexico.

Attending officials included Marcelo Ebrard, Mexico's Secretary of Economy, and Mario García Valdez, Secretary of Economic Development of San Luis Potosí. The two sides confirmed their shared resolve to back the company's local investment and regional growth. Separately, HS HYOSUNG's leadership met bilaterally with Secretary Ebrard to elaborate on its strategic vision and investment plans.

The agreement sets out a phased expansion of HS HYOSUNG's investments in San Luis Potosí beginning in 2027, with the goal of creating a major advanced materials production hub that bolsters supply for North American and wider global markets. The company's advanced materials span tyre cord, a flagship world-leading product, along with mobility, energy, aerospace and defence applications. Its North American operations, spanning Mexico and the United States, turn out tyre cord, airbag materials and mobility interior components for global leaders such as General Motors and Goodyear, underpinned by a highly dependable global supply chain.

Nak-yang Sung, CEO, HS HYOSUNG ADVANCED MATERIALS, said, “This investment goes beyond establishing a simple manufacturing base – it reflects our strategy to turn Mexico into a pivotal hub connecting North America with global supply networks. We are also committed to strengthening local supply chains and creating high-quality jobs to contribute directly to the region's industrial ecosystem.”

Kumho Petrochemical Group Shifts Focus To R&D and Speciality Materials

Kumho Petrochemical Group Shifts Focus To R&D and Speciality Materials

Kumho Petrochemical Group is steering its business towards research-driven, higher-value outputs as oversupply and soft demand continue to weigh on the worldwide petrochemical sector. The Seoul-based group outlined plans to boost spending on speciality chemicals, sustainable materials and novel production methods, a push intended to lift profits while building a foundation for future expansion.

Underlying the move is a deliberate evolution in the group's identity, from a bulk materials vendor to a provider of technology-backed solutions that address shifting customer requirements and stricter environmental rules. A central element of that effort involves widening the speciality lineup, exemplified by added capacity for solution styrene butadiene rubber, a synthetic rubber that enhances durability, rolling resistance and tread wear in high-performance electric vehicle tyres.

Environmental initiatives form another pillar. Facilities built by the company can trap approximately 76,000 metric tonnes of carbon dioxide each year, while separately developed technology turns recycled acrylonitrile butadiene styrene sourced from scrapped household appliances into automotive-grade interior components that satisfy performance standards and generate fewer emissions than conventional methods. The group has also joined forces with POSCO Future M and BEI on anode-free lithium-metal battery development.

Parallel technology-focused programmes are underway at affiliated units. Kumho P&B Chemicals is formulating water-based epoxy resins that curb volatile organic compound releases while incorporating more bio-based inputs to reduce carbon intensity. Kumho Mitsui Chemicals is advancing bio-based polyurethane systems and electric vehicle materials, alongside debottlenecking work to add 100,000 tonnes of annual methylene diphenyl diisocyanate capacity. Kumho Polychem, meanwhile, is targeting ethylene propylene diene monomer through low-temperature polymerisation paired with energy-efficiency improvements.

Birla Carbon Announces Asia-Wide Speciality Materials Price Hike Of Up To 15%

Birla Carbon Announces Asia-Wide Speciality Materials Price Hike Of Up To 15%

Birla Carbon has confirmed a price increase of up to 15 percent for its Speciality Materials products across Asia, scheduled to take effect on 1 October 2026. The company pointed to significant and sustained rises in feedstock costs, driven partly by ongoing geopolitical instability and disruptions in global feedstock markets, as the reason behind the adjustment.

Although Birla Carbon pursued operational efficiencies, supply chain optimisation and disciplined cost management to soften the impact, the scale and persistence of the cost escalation left a price adjustment unavoidable. The company's sales teams will engage customers directly to explain the details and help them navigate the transition.