Vehicular transport, particularly passenger cars, has significantly enhanced human mobility and modern living standards. Meanwhile, the global dependence on rubber-based tires—composed of both natural elastomers and synthetic polymers—has engendered persistent environmental burdens. Tire Wear Particles (TWPs), microscopic particles generated through interfacial abrasion between vehicular tires and road pavements, have become an escalating contamination concern due to their toxic effects on ecosystems and increasing abundance worldwide (Rogge et al., 1993; Kreider et al., 2010; Kole et al., 2017; Wagner et al., 2018; Tian et al., 2021; Mian et al.,2022). With annual release of over 6 million tons into the environment, TWPs as major contributors of microplastics (MPs), are being one of the hot topics in environmental researches (Evangeliou et al., 2020; Xu et al., 2020; Gehrke et al., 2023).

The occurrence of TWPs in the environment is governed by multiple factors, including vehicle driving behaviors, road surface types, tire specifications, and ambient conditions, resulting in the pollution characteristics like broad size distributions (0.1 μm to 5 mm), heterogeneous morphologies, and complex chemical compositions (Kole et al., 2017; Chen et al., 2022). Notably, TWPs possess high specific surface areas and marked hydrophobicity, enabling strong adsorption affinities for co-occurring pollutants such as vehicular exhaust particulates, heavy metals (e.g., Zn, Pb), and antibiotics (e.g., tetracycline). The synergistic interactions between TWPs and adsorbed contaminants may amplify their combined ecotoxicological impacts (Hüffer et al., 2019; Ding et al., 2021; Glaubitz et al., 2023).

Environmental monitoring data have confirmed the pervasive distribution of TWPs in global atmospheric, terrestrial, and marine compartments like air, road dusts, soil, snow, stormwater runoff, wastewater treatment systems, rivers, lakes, seas, and sediments (Baensch-Baltruschat et al., 2021; Goßmann et al., 2021; Järlskog et al., 2022; Müller et al., 2022a; Zhao et al., 2024). It is estimated that TWPs may contribute to 26–74% of total MPs loads in the environment (Xu et al., 2020; Gehrke et al., 2023). Bioavailable additives (e.g., zinc, benzothiazoles) leached from the TWPs may induce sublethal impairments in growth allometry, developmental homeostasis, and reproductive fitness in organisms (Goßmann et al., 2021; Ertel et al., 2023). TWPs can also be ingested by organisms and then transfer through food webs (Auta et al., 2017; Parker et al., 2020). Thus TWPs pose significant potential threats to global ecosystems and human health especially in a background that the vast global TWPs emissions every year (Baensch-Baltruschat et al., 2020). TWPs has been a priority emerging pollutant requiring monitoring and control in the environment (Wik and Dave, 2009; Rødland et al., 2023; Kole et al., 2017; Wagner et al., 2018; Baensch-Baltruschat et al., 2020; Gehrke et al., 2023; Mayer et al., 2024).

Although TWPs mainly originate from land, their small size and light weight make them easily transport for long distance through air circulation, precipitation, and surface/subsurface runoff, ultimately enter the marine environments ( Figure 1 ) (Evangeliou et al., 2020; Baensch-Baltruschat et al., 2021). TWPs contribute up to 15% of marine MPs pollution, meaning up to 350,000 tons of TWPs entering the ocean each year and the annual input of TWPs to the ocean is suggested to increase year by year (Meng et al., 2020; Kushwaha et al., 2024). The ocean covers about 71% of the earth’s surface, thus the ocean is a potentially significant accumulation site for TWPs and serves as the ultimate sink for TWPs.

TWPs could induce profound and unpredictable impacts on marine ecological systems because of their particular physical and chemical properties, resulting in higher environmental and health risks compared with other types of MPs (Galafassi et al., 2019; Halle et al., 2020; John et al., 2022). An increasing number of studies have demonstrated that TWPs might interfere with marine biogeochemical cycles and undermine the equilibrium of marine ecosystems (Roch et al., 2019; Cunningham et al., 2024; Wang et al., 2024c; Zhang et al., 2025b). Tires are usually compounded with a large number of chemical additives, including plasticizers and vulcanizing agents. These chemical additives contain heavy metals such as chromium and nickel, as well as a variety of organic contaminants such as PAHs and N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPD), many of which are leachable in water (Kushwaha et al., 2024; Chen et al., 2025). Moreover, TWPs could also adsorb contaminants such as antibiotics, thus inducing joint toxicity (Wen et al., 2024; Ganie et al., 2025). Studies have shown varying degrees of toxic effects of TWPs and their leachates on different kinds of marine life, including bacteria, algae, phytoplankton, zooplankton, crustaceans, and fishes (Halle et al., 2021; Yu et al., 2023; Boisseaux et al., 2024; Li et al., 2024d). Emerging evidence confirmed the pervasive presence of TWPs in marine biota, possibly cause risks to ecosystem through trophic transfer (Wang et al., 2023a). TWPs also tend to accumulate progressively with increased intake and become amplified through bioaccumulation in the food chain and ultimately detected in the human body, posing potential threats to human health (Roch et al., 2019; Chai et al., 2024). Consequently, TWPs pollution in marine ecosystems cannot be ignored.

A total of 249 relevant publications since 2018 to 2025 maily in the Web of Science, PubMed, and the China National Knowledge Infrastructure (CNKI) were selected. ‘Tire wear particles’ was used as the subject headings coupled with key words marine, sea, microplastic particle, behavior, toxicity, monitoring, control, etc. Based on literature review, global research on TWPs has predominantly focused on regions spanning from the east coast of North America to the west coast of Europe, including Arctic areas. Additionally, investigations are gradually expanding to coastal zones near South Korea, Japan, and parts of China’s Pacific coastline. This article comprehensively reviews the sources, migration of TWPs and their ecological risks in the marine environments, and explores the potential control strategies, aiming to provide support for the comprehensive understanding of the environmental behaviour of TWPs and effective control measures of TWPs pollution in marine ecosystems.

TWPs are primarily generated through the tribological interaction between tires and road surfaces, thus particles detached from tires during transportation activities are the greatest contributors to TWPs emission (Zhang et al., 2024a). At the global scale, around 3 billion new tires are produced, and 800 million are reaching end-of-life status annually (Kole et al., 2017; Mayer et al., 2024). During operational use, 10–30% of the tire tread mass undergoes progressive attrition, forming TWPs that would disperse into environmental matrices through mechanical shear and aerosolization processes (Wagner et al., 2018). The annual release of TWPs exceed 6 million tons globally, with per capita emissions ranging from 0.20 to 5.5 kg/year (mean: 0.81 kg/year) across different economic regions (Baensch-Baltruschat et al., 2020; Evangeliou et al., 2020; Kole et al., 2017).

Research revealed TWPs emissions occur across all vehicle types at varying levels, with light-duty passenger cars averaging 100 mg/vehicle·km, while heavy-duty trucks reaching up to 1,200 mg/vehicle·km (Baensch-Baltruschat et al., 2020; Lee et al., 2020). Notably, hybrid electric vehicles demonstrate 18-22% higher tire wear rates compared to conventional internal combustion engine vehicles, attributable to increased mass from battery systems and regenerative braking-induced torque variations (Liu et al., 2022a; Arole et al., 2023). While accelerating electric vehicle deployment is pivotal for decarbonizing transportation in the world, the concomitant increase in TWPs emissions presents an emerging environmental challenge. The extreme operational conditions of aircraft tires are likely to exacerbate the generation rates of TWPs by 3–5 times compared to those of highway vehicles. A case study at Frankfurt Airport (2014) quantified annual aircraft TWPs emissions at 83 metric tons (Spanheimer and Katrakova-Krüger, 2022). Coastal regions, which concentrate the world’s highest population densities, significantly contribute to transport-related TWPs emissions due to intensified vehicular traffic and increased aviation activity.

Factors encompassing tire composition (natural/synthetic rubber ratios, tread design), pavement characteristics (surface roughness, hardness), vehicular parameters (axle load, velocity profiles), and driver behavior patterns (braking intensity, acceleration frequency) would strongly affect the emissions and characteristics of TWPs (Kole et al., 2017; Zhang et al., 2023b). TWPs are typically composed of synthetic rubber, fillers (e.g., carbon black), plasticizers, and road-derived particulates ( Table 1 ), ranging in size from micrometers to millimeters (averaging 10–100 micrometers) (Kreider et al., 2010; Wagner et al., 2018; Amelia et al., 2021). Nascent TWPs typically demonstrate sub-aqueous densities (0.95-1.05 g/cm³), whereas in the environment, TWPs show elevated density ranges (1.20-1.70 g/cm³) due to their agglomerating with high-density road-derived materials (e.g., asphalt particles: 2.3-2.5 g/cm³) through thermomechanical adhesion processes (Kole et al., 2017; Baensch-Baltruschat et al., 2020; Kovochich et al., 2021). Once emitted, TWPs release into the ambient air or settle on the road surface, where their diameter and density play a critical role in determining their environmental behavior and fate (Wagner et al., 2018; Baensch-Baltruschat et al., 2021).

Synchronized monitoring data indicate that TWPs within various forms are primarily transported to marine environment through atmospheric dry/wet deposition and surface runoff. Fine TWPs with diameters below 10 μm (accounting for 0.1–10% of the total emissions) could remain suspended in the atmosphere for long periods of time due to their aerodynamic properties, increasing their potential for transboundary environmental impacts (Järlskog et al., 2020; Baensch-Baltruschat et al., 2021; Goßmann et al., 2023; Li et al., 2024e). The airborne concentrations of TWPs were reported in the range of 0.4-11μg/m³ (Wik and Dave, 2009). Wind-driven suspension facilitates long-range atmospheric transport of TWPs (Kole et al., 2017), with concentrations reaching 35 ng/m³ in coastal air over Norway (Goßmann et al., 2023). Evangeliou et al. (2020) suggested that direct deposition of airborne road TWPs was likely the most important source for the ocean, and about 30% of the emitted TWPs (140 kt yr⁻¹) were deposited in the world ocean through atmospheric transport. Atmospheric dispersion enables TWPs to deposit in remote marine environments far from emission sources, contributing to their global distribution.

The high mobility of water enables fluvial long-distance transport of TWPs, thus surface runoff is another key pathway for TWPs to enter marine ecosystems (Leads and Weinstein, 2019). Large TWPs with particle sizes between 10 μm and 500μm undergo transient deposition on road surfaces or adjacent soils, subsequent rainfall can transport them into urban drainage systems, thus TWPs would enter into waters via stormwater runoff (Huber et al., 2016; Baensch-Baltruschat et al., 2020). Urban street cleaning activities could accelerate TWPs entry into aquatic systems (Wik and Dave, 2009; Huber et al., 2016; Smyth et al., 2025). TWPs retained on road surfaces typically form heterogeneous aggregates with dust and road particles during runoff events. These aggregates undergo coagulation, aging, and co-transport with pollutants before entering roadside streams or wastewater treatment systems (Unice et al., 2019; Dupasquier et al., 2023; Li et al., 2023a; Li et al., 2024b; Li et al., 2024c). TWPs have reportedly reached concentrations of up to 179 mg/L in stormwater drainage (Parker-Jurd et al., 2021, 2025). It was estimated that 2.8–18.6% of micron-sized TWPs were discharged from land into freshwater bodies and rivers, and the high mobility of water enabled long-distance transport of TWPs to the ocean (Jambeck et al., 2015; Essel et al., 2015; Leads and Weinstein, 2019; Lebreton et al., 2017; Wang et al., 2024c). Siegfried et al. (2017) estimated that European rivers discharge approximately 1.2 kt of TWPs annually into the Atlantic Ocean. Continental modeling confirmed that terrestrial TWPs, particularly sub-100 μm particles, are efficiently transported via fluvial systems to marine ecosystems, with annual global fluxes estimated at 1.3-4.7 teragrams (Essel et al., 2015). Parker-Jurd et al. (2021) pioneered a flux quantification framework using benzothiazole biomarkers, identifying treated wastewater effluent, urban surface runoff, and atmospheric fallout as three dominant TWPs entry routes into marine systems. Later they quantified TWPs entering estuaries in stormwater drainage, surface waters and sediments in the marine environment, at concentrations of 0.4 mg/L, 0.00063 mg/L, and 0.96 g/kg, respectively (Parker-Jurd et al., 2025). At present, TWPs have been commonly detected in aquatic environments around the world (Wang et al., 2024b).

The global marine input flux of TWPs exhibits significant spatial heterogeneity. Current research on TWPs predominantly focuses on waters of developed countries, such as the United States, Sweden, Germany, Japan, and Norway (Siegfried et al., 2017; Goßmann et al., 2023), where substantial TWPs in marine environments have been consistently documented ( Table 2 ). Among continents, the North America and the Europe are among the largest contributors, and China’s rapid motorization contributed significantly to TWPs emissions in Asia (Evangeliou et al., 2020; Wu et al., 2024). In contrast, data about the developing countries were not so comprehensive becasuse of the relative poor robust monitoring systems in those countries (Wang et al., 2024b). With the growing evidence base for TWPs distribution across various environmental compartments, the pathways of TWPs entering the ocean have been largely elucidated. However, current calculations of TWPs fluxes and their inputs into the ocean predominantly rely on modeling estimations and lack empirical data (Pan et al., 2023; Xu et al., 2024b; Zheng et al., 2025; Parker-Jurd et al., 2025). Future research should prioritize establishing a global monitoring network to quantify the generation, transport, and environmental distribution of TWPs. This initiative is critical for obtaining accurate mass balance data, which will enable a more scientifically grounded allocation of national responsibilities.

The migration behaviors of TWPs in marine systems, were primarily governed by both their physicochemical properties and the environmental factors of the ocean (Kole et al., 2017). The size, shape, density, surface charge, and other characteristics of TWPs affected the rate of suspension, settling, and dispersion of TWPs in the sea. Lighter and little TWPs can remain suspended in water for extended periods, dispersing via ocean currents, while denser and large particles are more prone to sedimentation on the seabed (Unice et al., 2019; Wang et al., 2024c). Most of TWPs ultimately assumbled in coastal sediments, with concentrations 2–5 orders of magnitude higher than those in pelagic regions (Unice et al., 2019; Lee et al., 2020; Roychand and Pramanik, 2020; Rauert et al., 2022a, 2022b). A hydrodynamic modeling revealed 67–89% TWPs entering the ocean from land would deposit in bays retained in estuarine transition zones, with resuspension rates inversely correlated to sediment organic carbon content (Parker-Jurd et al., 2021). Studies found that synthetic rubber-containing carbon particles predominantly derived from TWPs constituted 15-38% microplastics in coastal sediments, with the 1.6-20 μm size fraction representing >60% of total TWPs mass (Kole et al., 2017; Ziajahromi et al., 2020; Gaggini et al., 2024). Semi-enclosed coastal systems (e.g., urban estuaries in the U.S.) exhibit significant TWPs accumulation, with sediment concentrations reaching 7,515 particles/kg, exceeding those in open oceans (Klöckner et al., 2020; Zhu et al., 2021). Of particular concern is the detection of microplastics (MPs), including TWPs, in Pacific abyssal sediments (4,900-7,016 m depth), where maximum concentrations reach 111.3 ± 75.1 items/kg dw as well as the spatial distribution patterns correlated strongly with the Great Pacific Garbage Patch (GPGP) location and current systems (Deng et al., 2025). Tidal dynamics facilitated the transport of TWPs from terrestrial sources to coastal zones through periodic water level fluctuations. Accelerated sea-level rise has increased the frequency of tidal flooding in coastal cities, potentially elevating TWPs fluxes to marine ecosystems by 23-41% (Ertel et al., 2023). Global ocean circulation patterns further contribute to the wide distribution of TWPs in the ocean, with polar regions acting as potential sinks. The deposition of TWPs on Arctic ice exacerbated ice melt through radiative forcing—a mechanism analogous to black carbon impacts (Materić et al., 2022).

Environmental variations induce the transformation of TWPs in marine systems, thereby significantly altering their fate. Temperature changes, UV irradiation and microbial activity, could affect the stability and transport of TWPs (Weyrauch et al., 2023; Zhao et al., 2024). TWPs might undergo physical fragmentation processes such as weathering and water shear, chemical oxidation processes such as photo-oxidation, ozone decomposition, thermal oxidation and biodegradation in the ocean. These processes lead to decomposition, further fragmentation and physicochemical property changes of TWPs, exchanging their morphology, density, and elemental composition, thereby enhancing their mobility in aquatic systems (Chen et al., 2022; Shin et al., 2023; Wagner et al., 2022; Weyrauch et al., 2023; Li et al., 2024a). Notably, aged TWPs demonstrate enhanced adsorption and transport capacities compared to pristine particles (Wagner et al., 2022; Weyrauch et al., 2023; Li et al., 2024f). As effective adsorbents, TWPs interact with environmental contaminants through their polymer-rubber and carbon-black components (Hüffer et al., 2019). Their adsorption affinity for antibiotics resembles that of carbonaceous materials, with aging further amplifying antibiotic adsorption efficiency (Fan et al., 2021; Wen et al., 2024). Xu et al. (2024) revealed that TWPs and their leachates substantially increase the abundance and diversity of antibiotic resistance genes (ARGs) and virulence factor genes (VFGs) in coastal sediments (Xu et al., 2024a).

TWPs that enter marine environment can be re-emitted into the atmosphere or transported back to terrestrial ecosystems via multiple pathways. Sea spray aerosols generated by wave-breaking processes can reintroduce suspended TWPs into the atmospheric boundary layer (Sha et al., 2024). Through ingestion and bioaccumulation in marine organisms, TWPs may transfer back to land-based ecosystems via animal and human consumption (Weinstein et al., 2022; Laubach et al., 2025; Lian et al., 2025). According to McIntyre’s TWPs exposure experiment, the cumulative rate of TWPs in Coho tissues can reach more than 35% (McIntyre et al., 2021). This finding highlights the urgency of conducting environmental risk assessments throughout the life cycle of TWPs, especially the need to quantify their global fluxes through “ocean-atmosphere-land” multi-media migration and “aquatic food chain-human” exposure pathways.

To our knowledge, data on the migration of TWPs in the marine environment were still scarce because of some technological and environmental issues, posing significant challenges in tracking their transport pathways, spatial distribution, and potential accumulation in the ocean. Limited large-scale application of tracing technologies (e.g., stable isotope labeling) hindered comprehensive quantitative analysis of TWPs migration pathways. Although Py-GC/MS coupling technology has reduced the detection limit of TWPs to 0.02 μg/g, complex marine matrices still result in 30-45% false-negative rates (Rauert et al., 2022a). Dynamic ocean currents, water movements, biological activities, and sediment deposition patterns, further complicates the detection and quantification of TWPs. These factors collectively obscure our understanding of how TWPs transport and transformation in the marine environment.

TWPs exhibit certain physical and chemical properties like conventional MPs, whereas their primary compositions differ from those of MPs as well as they contain much more toxic chemical additives (Halle et al., 2020; Wang et al., 2023b; Rizwan et al., 2024), resulting in greater potential environmental and health risks. Distinct from conventional MPs, to enhance vehicular safety parameters such as traction efficiency and mechanical durability, tires are reinforced by synthetic rubber matrices and specialized additive formulation, governing post-consumption environmental interactions, including contaminant leaching kinetics and ecotoxicological impacts (Halle et al., 2020; Guo et al., 2024). The cross-linked polymer networks and stabilized additive packages in TWPs confer superior environmental persistence (Barbara et al., 2023), leading to progressively release of complex leachates as well as posing heightened ecological risks through bioaccumulation and interference with biogeochemical cycles (Wik and Dave, 2009; Jambeck et al., 2015; Laubach et al., 2025). TWPs can also readily adsorb environmental contaminants such as heavy metals and PAHs (Cassandra et al., 2022), and such adsorption processes have been suggested to exert greater chemical impacts on water quality than the particles themselves (Vogel et al., 2024; Ganie et al., 2025).

Commonly, TWPs leachates contain measurable concentrations of toxic chemical additives such as heavy metals (Zn, Pb, Cd) and organic pollutants including polycyclic aromatic hydrocarbons and benzothiazole derivatives ( Table 3 ). Wu et al. (2024) systematically investigated the chemical components of TWPs through controlled abrasion experiments using a standardized tire profile simulator, quantifying 18 elements and 20 PAHs from 17 commercially dominant tire models in China. In an environmental leaching study, about 60% of 203 organic compounds identified in TWPs were observed within aqueous-phase mobilization potential (Müller et al., 2022). These chemical additives dissolved in the leachates accounted for 72-89% of observed toxicity, surpassing physical toxicity from particle presence (Rødland et al., 2023). For example, TWPs leachates exhibited higher toxicity (EC₅₀=0.04-8.60 mg/L) than intact particles on Chlorella vulgaris and biphenylamine derivatives were observed much more toxic (Jiang et al., 2024). An acute exposure study demonstrated 3.2-fold higher toxicity of TWPs leachates compared to particulate matter itself, attributable to enhanced bioavailability of dissolved contaminants (Caballero-Carretero et al., 2024). 6PPD (N-(1,3-dimethylbutyl)-N′-phenyl-pphenylenediamine), an antioxidant ubiquitously employed in tire formulations was observed undergoing rapid quinoid transformation to 6PPD-quinone (6PPD-Q), a compound demonstrating acute aquatic toxicity at ng/L concentrations (LC₅₀=0.62 μg/L for Oncorhynchus mykiss) (Ihenetu et al., 2024; Jiang et al., 2024; Calle et al., 2025). Tian et al. (2020) found that 6PPD-Q induced 100% mortality in coho salmon (Oncorhynchus kisutch) at environmental concentrations. Multi-continental surveys detected 6PPD-Q in nearly 90% of urban stormwater samples, with concentrations exceeding ecotoxicological thresholds by 2–3 orders of magnitude (Tian et al., 2021; Yao et al., 2024).

A growing body of research confirms that TWPs exert toxic effects on various marine organisms through multiple pathways, posing a potential threat to marine ecosystems (Siddiqui et al., 2022; Bournaka et al., 2023; Wang et al., 2024c; Yang et al., 2025b). TWPs could change the microbial community composition and function like MPs (Peng et al., 2024; Zhang et al., 2025b). Ding et al. (2022) revealed that environmentally relevant concentrations of TWPs (1% weight/dry weight) could significantly change the microbial community structure, decrease community diversity, and inhibit nutrient cycling processes, including carbon fixation and degradation, nitrification, denitrification, and sulfur cycling in coastal sediments. Liu et al. (2022b) found that exposure to TWPs (150g/kg) could lead to a shift in bacteria community and affect nitrogen metabolism in marine sediments. The effects of TWPs on aquatic organisms showed a significant dose-dependent effects. At low concentrations (0.6 and 3 mg/L), TWPs stimulated the growth of microalgae Phaeodactylum tricornutum, whereas higher concentrations (15 and 75 mg/L) significantly inhibited growth, reduced chlorophyll-a content, and induced oxidative damage in algal cells (Lv et al., 2024). Page et al. (2022) revealed a significant negative impact of TWPs leachates on the growth rates of three marine phytoplankton species. The 72-h median effect concentration (EC50) values were determined to be 0.23 g/L for the cryptophyte Rhodomonas salina, 0.64 g/L for the diatom Thalassiosira weissflogii, and 0.73 g/L for the dinoflagellate Heterocapsa steinii. Notably, leachate concentrations equivalent to or exceeding 90% of 1 g/L TWP resulted in 100% mortality for all three species within 72 h. Since primary production plays a key role in the marine food web, the growth inhibition and ethality of primary producers such as phytoplankton and macroalgae by TWPs might disrupt the primary production network and the stability of aquatic food webs in the ocean (Wang et al., 2024c). Studies showed that TWPs and their leachates also exhibited toxic effects on higher marine trophic levels such as zooplankton, mollusca and fish ( Table 4 ), posing a profound impact on the structure and function of the entire aquatic ecosystem. For example, exposure of Tigriopus japonicus to 0.17 g/L TWPs leachate for 48 hours caused severe oxidative stress, and activities of superoxide dismutase (SOD), glutathione (GSH) and glutathione-S-transferase (GST) decreased to 44.5%, 7.08% and 15.6%, respectively (Yang et al., 2025b); the water filtration rate and respiration rate of juvenile oyster (Crassostrea gigas) decreased by 52% and 16% within 40.5 hours at 1 μg/mL TWPs leachates (Tallec et al., 2022); 500 mg/L of TWPs significantly prolonged the burial time of Eriocheir sinensis, affecting the antioxidant defense system and energy metabolism (Ni et al., 2023, 2024); 6PPD led to developmental abnormalities in zebrafish (Danio rerio) embryos (Cunningham et al., 2022) and reproductive impairment in Daphnia magna (Boisseaux et al., 2024; Cunningham et al., 2024).

Emerging evidence confirmed the pervasive presence of TWPs in marine biota, possibly cause ecological risks through trophic transfer (Wang et al., 2023a). Numerous aquatic species have been documented to ingest TWPs, and the accumulation of those absorbed pollutants in marine organisms may exacerbate their adverse effects on marine ecosystems, potentially compromising food web stability and ecosystem health (Halle et al., 2021; Boisseaux et al., 2024; Philibert et al., 2024). 6PPD and 6PPD-Q, have been detected in various fish species including bighead carp (Hypophthalmichthys nobilis), sea bream (Sparidae), and mackerel (Scomberomorus spp.) (Ji et al., 2022). Foscari et al. (2025) revealed significant bioaccumulation of tire additives in blue mussels (Mytilus edulis), and all quantifiable 21 tire-related chemicals were found at significantly higher concentrations in mussel’s tissue than in tested water, with N,N′-diphenyl-1,4-phenylenediamine(DPPD), N,N′-di-(p-tolyl)-p- phenylenediamine(DTPD) and 4-Hydroxydiphenyl amine(4-HDPA) concentrations more than 50 times higher than water levels. Suspect and non-target screening found 37 additional transformation products of tire additives, many of which did not decrease in concentration during depuration. Chai et al. (2024) demonstrated that the ecotoxicity of TWPs leachate can be transferred and amplified across multi-generations and different trophic levels through food chain (microalgae-zooplankton-fish). The study showed that the growth of microalgae (Chlorella pyrenoidosa) was significantly inhibited at TWPs leachate concentration ≥1500 mg/L. For rotifers (Brachionus calyciflorus) fed with TWPs-contaminated microalgae, the 500 mg/L group showed reduced reproductive capacity starting from the 3rd generation and the 1000 mg/L group went extinct after the 5th generation.When carp larvae consumed contaminated rotifers from the group higher than 250 mg/L, their mortality increased, and body length/weight decreased by over 30%. Yu et al. (2023) have specifically addressed the ecological risks and potential human health implications via dietary exposure. Primary producers in marine environment, phytoplankton may initiate trophic transfer through uptake of TWPs from aquatic matrices. Filter-feeding organisms subsequently ingest these particles through consumption of suspended particulate matter. The bioaccumulation process continues through higher trophic levels, ultimately affecting marine mammals. As apex consumers, humans may be exposed to TWPs through consumption of contaminated seafood (Roch et al., 2019). Due to their bioaccumulation potential and persistent release of toxic additives, TWPs represent a significant ecological threat in marine environments that demands urgent scientific attention (Youn et al., 2021).

Current information indicated TWPs could cause the abnormality and death of marine life at certain concentrations in the lab, but there are still great challenges in comprehensively assessing TWPs ecological risks. Most of exposure experiments conducted were predominantly limited to short-term studies, which failed to reflect the long-term ecological effects of TWPs. Moreover, the tested concentrations often significantly exceed those found in real-world environments. Whether death occur in the real marine environment has not been investigated, thus long-term in-field studies are called for further investigation.

Given the substantial global production and disposal volumes of tires, TWPs represent an emerging contaminant that has significant impacts on the marine environment. Studies have shown that the introduction of TWPs into the ocean may change the composition of organic matter in the marine system, which in turn will interfere with the stability and function of the marine ecosystem. This alteration in the composition of marine organic matter may lead to the accumulation of harmful substances in marine organisms, ultimately affecting human health through the food chain, and there is also a potential risk of direct or indirect harm to human health from the chemicals that TWPs themselves may carry. A comprehensive understanding of TWPs sources, transport mechanisms, and ecological impacts is essential for knowing their marine environmental behavior assessing associated ecological risks, and developing targeted control measures. The complex characteristics of TWPs like heterogeneous chemical composition, morphological diversity, polydisperse size distribution, and variable density characteristics, created substantial challenges for environmental monitoring, risk quantification, and pollution management of TWPs. Current environmental behavior and exposure studies predominantly utilize laboratory-synthesized or commercially procured TWPs, which may not accurately represent natural environmental conditions. Consequently, investigating TWPs environmental impacts requires integrated approaches that account for multiple interacting factors to better predict their environmental fate and effects. Presently, insufficient data exists regarding intrinsic TWPs properties and environmental parameters to comprehensively evaluate alterations in marine ecosystem induced by TWPs. This knowledge gap underscores the need for more rigorous assessment of TWPs impacts on environmental health.

Based on current research progress of TWPs in the marine environment, the following future research priorities are recommended to address critical knowledge gaps and emerging challenges: