Emerging Challenges from Plastics-Driven Climate Change and Microplastics

Abstract

Greenhouse gas emissions associated with plastic production and disposal span the entire plastic life cycle, establishing a direct link between plastic pollution and climate change. This review demonstrates that micro- and nanoplastics (MNPs) also function as active components of climate feedback systems by disrupting marine trophic structures, altering microbial assemblages, and diminishing the ocean’s capacity for carbon storage. Synthesized evidence further indicates that environmental degradation of polymers enhances surface reactivity, facilitating the sorption and transport of persistent contaminants, including per- and polyfluoroalkyl substances (PFAS) and antibiotic-resistant bacteria (ARB). These interactions amplify combined risks to ecosystems and public health under climate change scenarios. This review also reveals that many existing remediation strategies prioritize waste reduction or physical removal while failing to account for contaminant–plastic–climate interactions, thereby limiting their long-term effectiveness. By integrating climate-related processes, polymer transformation, and contaminant dynamics, this review identifies critical knowledge gaps and underscores the need for mitigation strategies that jointly address plastic pollution, climate feedbacks, and emerging public health threats.

1. Introduction

Plastics are being produced and used at an accelerating rate worldwide, with global production projected to reach approximately 445.25 million metric tons by 2025 [1]. The extensive use and disposal of plastic materials has raised substantial concerns about the accumulation and persistence of plastic waste in the environment across terrestrial, aquatic, and atmospheric systems. Recent studies [2] have identified a correlation between plastics and climate change, particularly highlighting how different polymer types contribute differently to greenhouse gas emissions throughout their life cycles, including production, use, degradation, and end-of-life stages.

Climate change further accelerates the fragmentation and transformation of plastic debris into micro- and nanoplastics (MNPs) through enhanced ultraviolet radiation, thermal stress, mechanical weathering, and extreme weather events. These processes increase the abundance, mobility, and environmental persistence of MNPs while altering their surface properties and reactivity. As a result, plastic pollution and climate change form a reinforcing feedback loop in which plastic production and degradation contribute to greenhouse gas emissions, while climate-driven stressors intensify microplastic generation and dispersion.

The challenges associated with mitigating MNPs—particles smaller than 5 mm and 1 µm, respectively—stem from their diverse and often diffuse sources, including nonpoint inputs such as tire wear and textile fibers. Additional challenges arise from the lack of standardized analytical methods for detecting and characterizing MNPs. Further barriers include insufficient regulatory frameworks, weak enforcement of existing policies, and limited public awareness, as reflected in limited willingness to reduce plastic consumption. Together, these limitations hinder effective risk assessment and management of MP pollution under a changing climate.

Emerging contaminants such as per- and polyfluoroalkyl substances (PFAS) and antibiotic-resistant bacteria (ARB) exhibit strong adsorption to MPs, complicating their removal through advanced treatment technologies. MPs can therefore act as vectors for contaminant transport and exposure, posing indirect risks to ecosystems and human health. Adsorption capacity depends on polymer type; for instance, antibiotics, perfluoroalkyl compounds, and triclosan adsorb particularly strongly onto polyethylene (PE) and polystyrene (PS) MPs [3]. Climate-related stressors may further modify sorption–desorption dynamics, influencing contaminant persistence and bioavailability.

This review examines the interactions between MPs, climate change, and emerging contaminants, with a particular focus on how climate-driven transformation of plastic polymers influences contaminant fate, transport, and persistence. It also proposes strategies to mitigate these challenges by integrating perspectives from environmental chemistry, climate science, toxicology, and public health, with the goal of reducing risks to public health and the environment and identifying key knowledge gaps and future research priorities. Specifically, the review focuses on the mechanistic pathways linking plastic pollution to climate feedbacks and contaminant dynamics, while critically evaluating the implications for remediation strategies and public health.

2. Microplastic Effects on Climate Change

Life cycle assessments indicate that conventional plastics are significant contributors to global greenhouse gas (GHG) emissions and are projected to account for up to 15% of the global carbon budget by 2050, considering the full life-cycle emissions from raw material extraction, polymer production, use, and end-of-life treatment [4]. Several studies [2,5] have evaluated alternatives to conventional plastics or examined emissions associated with the production of polypropylene (PP) and mixed PP–PE–Polyethylene Terephthalate (PET) products. Although sustainable substitutes—such as starch-based polymers—can reduce GHG emissions by 20–80%, depending on polymer type, production processes, end-of-life management, and life-cycle assessment boundaries, which introduce some uncertainty into these estimates, they also present drawbacks related to chemical additives, limited durability, and recycling challenges [2].

GHG emissions are highest during the polymer production stage, and emission intensity varies considerably by polymer type; for example, emissions from polystyrene (PS; 3.0 kg CO₂-eq kg⁻¹ plastic) are substantially higher than those from polypropylene (PP; 2.0 kg CO₂-eq kg⁻¹), which are approximately equivalent to those from low-density polyethylene (LDPE; 1.95 kg CO₂-eq kg⁻¹), and higher than those from high-density polyethylene (HDPE; 1.5 kg CO₂-eq kg⁻¹). Regarding end-of-life pathways, among the four primary waste management strategies—recycling, incineration, landfilling, and gasification—incineration generates the largest amount of GHG emissions. This is followed by gasification, recycling, and, lastly, landfilling [2,6,7]. These life-cycle emissions establish plastics as both direct and indirect contributors to climate forcing.

Alternatives to conventional petrochemical plastics are increasingly being explored as strategies to mitigate life-cycle GHG emissions. A recent study [2] identified four sustainable substitutes—starch-based polymers, polylactic acid (PLA) polyesters, polyhydroxyalkanoate (PHA) polyesters, and polycaprolactone (PCL) polyesters—each offering distinct advantages and limitations. Starch-based polymers, PHA polyesters, and PCL polyesters demonstrated GHG emission reductions of up to 80%, whereas PLA polyesters achieved a more modest reduction of approximately 25%.

Starch-based polymers are appealing because of their biodegradability and low cost, but their use is limited by poor mechanical strength. PLA polyesters provide the benefit of carbon-neutral raw material sourcing; however, they require extended composting periods of two to three months and degrade more slowly in landfills than conventional plastics. Although PLA is often marketed as a sustainable alternative, its slow degradation under landfill conditions highlights a potential greenwashing risk when industrial composting is unavailable, underscoring the importance of appropriate end-of-life management. PHA polyesters can degrade completely within 20 days under composting conditions using anaerobically digested sludge, though they exhibit reduced flexibility compared with petroleum-based plastics. Similarly, PCL polyesters fully degrade within approximately six weeks under composting conditions but have limited adaptability relative to PET and other aromatic polyesters. These trade-offs influence adoption potential and, ultimately, climate mitigation effectiveness.

During environmental degradation, plastics fragment into MNPs, introducing additional climate-relevant pathways beyond those associated with bulk plastic materials. For instance, MNPs present in oceans, sea ice, and the plastisphere have been identified as measurable and increasingly recognized sources of direct GHG emissions [8]. The primary pathways include: (a) direct GHG release from degrading plastics, (b) reductions in sea ice influenced by MP accumulation and associated heat absorption, (c) GHG emissions generated by the plastisphere—microbial communities colonizing plastic surfaces, (d) disruption of the ocean’s carbon sequestration capacity, and (e) enhanced soil carbon release driven by MP-induced changes in enzyme activity [8]. Notably, per unit mass, MPs generate more GHG emissions than larger plastic fragments due to their smaller size and greater surface area, and MPs in soil can further alter microbe-mediated GHG fluxes [8].

With the continued accumulation of plastic waste and improper disposal practices—combined with the recalcitrant nature of plastics—the contribution of MPs to climate change is expected to intensify. This establishes a feedback mechanism in which plastic degradation contributes to climate forcing, while climate change simultaneously accelerates plastic fragmentation and dispersion. Conversely, climate change also exerts a strong influence on MP distribution. Several recent studies [2,9] have demonstrated that climate change alters MP transport and fate through mechanisms such as disrupted ocean currents, rising temperatures, extreme weather events, and increased MP concentrations in natural environments. During extreme weather events, environmental pollution is amplified, leading to greater contamination of food and water sources with MPs. These interactions pose risks to both environmental integrity and public health.

A recent study [10] investigated the fate of MPs under climate change and demonstrated that temperature, rainfall, drought, and wind all influence MP sinks across aquatic, glacial, and terrestrial environments. However, it remains unclear whether these climate-driven shifts will lead to MP redistribution or produce synergistic impacts on aquatic and soil organisms. The review [10] also identified several climate-related MP degradation mechanisms—including those driven by wind and ocean currents, elevated temperatures, acid rain, and increased ultraviolet (UV) radiation—resulting in degradation through oxidation, thermal stress, freezing–thawing cycles, acidification, and UV exposure.

Concerns are growing regarding the role of MPs as vectors for contaminants, particularly emerging pollutants such as PFAS, especially because this vector pathway may also contribute to climate change. Despite this, relatively few studies have examined how MP–contaminant interactions influence climate processes. These interactions warrant greater attention, as they may pose substantial risks to both environmental ecosystems and public health.

Climate Change–Microplastic Nexus

The “climate change–microplastic nexus” refers to the bidirectional interactions between climate change and MPs, whereby climate-driven processes affect the sources, transport, fate, and impacts of MPs, while MPs and their life cycle may, in turn, influence climate-related processes and feedbacks. In this review, the term is used as a conceptual framework to synthesize evidence on these two-way interactions, highlight potential feedback mechanisms, and identify key knowledge gaps at the interface of these global environmental challenges.

Within the broader climate–plastic nexus, MP pollution represents both a consequence of climate change and a contributing factor to climate forcing. Climate-driven processes influence plastic production, degradation, transport, and accumulation, while plastics across their life cycle generate GHG emissions and alter ecosystem functions that regulate the global carbon cycle. Understanding this bidirectional relationship is essential for integrating plastic pollution into climate mitigation and adaptation strategies.

A growing body of research highlights a strong interconnection between climate change and MP pollution. Climate change serves as a major driver of MP accumulation by intensifying extreme weather events—such as droughts, hurricanes, floods, and wildfires—that enhance the mobilization, fragmentation, and redistribution of plastic debris. Additionally, climatic factors can alter the physicochemical properties of plastic particles, influencing their degradation pathways and environmental persistence.

Plastics accumulate across their life cycle through production, distribution, consumption, improper disposal, and gradual degradation into secondary microplastic and nanoplastic byproducts. Structural and chemical changes occurring during degradation directly influence GHG emission profiles. Experimental studies have shown that structural changes occurring during degradation can affect the release of GHG emissions; for example, Ford et al. (2022) [11] reported that LDPE emits higher levels of GHGs during degradation than HDPE, primarily due to its more highly branched polymer structure, lower crystallinity, and greater susceptibility to oxidative and microbial degradation. These emissions represent a climate feedback pathway whereby plastic degradation contributes directly to atmospheric GHG burdens.

The broader implications of microplastic accumulation in marine environments—such as disruption of physiological processes in marine organisms, alteration of food web dynamics, and reduced ecosystem functioning—may diminish the ocean’s capacity to act as a carbon sink, thereby potentially exacerbating climate change [12]. By impairing marine ecosystem structure and function, MPs indirectly weaken oceanic carbon sequestration, linking plastic pollution to climate regulation processes. While these effects are plausible based on current evidence, the overall impact of MPs on ocean carbon sequestration remains an emerging hypothesis that requires further experimental verification.

Despite growing evidence of these linkages, the environmental feedbacks between plastic pollution and climate change remain insufficiently understood, highlighting the need for mechanistic studies on the biogeochemical consequences of plastic accumulation in both marine and terrestrial ecosystems. Extreme weather events associated with climate change influence plastic pollution by modifying the distribution and concentration of plastic contaminants, including substances adsorbed onto plastic surfaces, via pathways such as disrupted ocean currents, elevated temperatures, and increased MP concentrations. The combined effects of climate change and MP pollution have particularly harmful impacts on ecosystems, affecting interactions among marine sediments, seawater, and resident biota [13].

Mitigation of MP pollution is most effective when terrestrial inputs are reduced, as climate-driven processes—such as flooding—can substantially elevate MP concentrations. For instance, recent studies [14,15,16,17] have shown that extreme weather events—such as typhoons, storms, and flooding—can substantially increase MP concentrations in seawater, sediments, and adjacent terrestrial environments, with the magnitude of increase varying depending on event intensity, hydrodynamic conditions, and environmental setting. The nexus between climate change and MP pollution warrants further investigation, particularly regarding ecosystem-level impacts and the development of remedial strategies, given MPs’ potential synergistic role as vectors for environmental contaminants.

In terms of future prospects, governments, in collaboration with the public and industry, should invest substantially in research and development (R&D) to address critical issues such as climate-driven increases in GHG emissions and elevated MP concentrations resulting from extreme weather events. Further studies are needed to characterize MP properties and their ecological impacts during degradation under varying climatic conditions. The potential synergistic role of MPs as vectors for contaminants also warrants closer examination, particularly regarding surface interactions and environmental factors that influence them. As plastics degrade, degradation pathways influence GHG emissions, while GHG dynamics may, in turn, affect degradation rates—yet these interdependencies remain poorly constrained. Investigating the kinetics of plastic polymer degradation alongside GHG emissions across diverse climatic scenarios is essential to understand the persistence and environmental impacts of plastics more comprehensively.

Moreover, as discussed previously, climate change affects the distribution of plastics, influencing their resuspension across environmental media. While emerging contaminants such as ARB associated with MPs are addressed in the following section, preventing and mitigating antibiotic resistance (AR) within microbial communities on plastic surfaces is critical to protecting both public health and the environment. Given that the adverse impacts of MPs are closely linked to their physicochemical properties, further research is needed to examine the relationship between MP characteristics and GHG emissions. From a circular economy perspective, comprehensive life-cycle assessments of plastics—from raw material extraction to disposal—are essential, alongside studies on pretreatment strategies for both conventional and alternative plastics. Such strategies could enable the efficient degradation of plastics, whether biodegradable or non-biodegradable, in natural environments or under controlled industrial conditions. Figure 1 shows how MPs, climate change, and their impacts are interconnected and highlights key research and mitigation priorities.

Unlike recent reviews that frame MPs and climate change primarily as co-occurring stressors, this review synthesizes emerging evidence within a mechanistic, cross-system framework that emphasizes causal pathways and reinforcing feedbacks. Climate-driven factors—including rising temperatures, enhanced ultraviolet radiation, and intensifying extreme weather—accelerate polymer fragmentation and oxidative degradation, directly increasing GHG emissions from MPs, particularly at smaller size fractions. In parallel, MPs disrupt biogeochemical carbon cycling by altering soil microbial activity and impairing marine primary productivity and the efficiency of the biological carbon pump, thereby reducing ecosystem carbon sequestration. Climate change further amplifies these impacts by redistributing MPs across environmental compartments, prolonging their exposure to degradation drivers and reinforcing plastic–climate feedbacks. This mechanistic synthesis moves beyond correlation and clarifies how MPs can actively contribute to climate forcing.

Overall, the interactions between climate change and microplastic pollution exemplify the broader climate–plastic nexus, in which plastics both shape and are shaped by climatic processes. Addressing this nexus requires integrated research that bridges polymer science, biogeochemistry, ecology, and climate science, alongside coordinated policy approaches that align plastic mitigation with climate goals.

3. Transformation of Plastic Polymers on Emerging Contaminants

Plastic polymers degrade under various climatic factors. However, it remains unclear whether the transformation of these polymers influences emerging contaminants adsorbed onto MPs, particularly through climate-driven changes in sorption, desorption, and transformation processes, as MPs function as vectors for contaminant transport. Climatic factors such as temperature fluctuations, UV exposure, drought, and precipitation events influence the formation of reactive oxygen species (ROS) and free radicals, which in turn drive polymer degradation and modify MP physicochemical properties, ultimately affecting the adsorption and behavior of co-occurring contaminants. One such emerging contaminant is PFAS, which poses challenges for treating wastewater and waste streams due to its recalcitrant nature. While landfill leachate contains a broad range of contaminants, emerging pollutants—including PFAS, pharmaceuticals and personal care products (PPCPs), and MPs—have received increasing attention regarding their quantification, remediation strategies, occurrence, frequency, and the role of climatic stressors in shaping their composition, degradation pathways, and treatment efficiency.

The coexistence of MPs with other contaminants has been shown—primarily based on experimental and observational studies—to affect multiple human organs, including the brain, heart, liver, thyroid, and lungs [18]. As MPs undergo climate-driven transformation, their altered surface chemistry, morphology, and aging characteristics influence contaminant adsorption, mobility, and interactions with co-occurring pollutants, thereby impacting both ecological and human-health outcomes. Such interactions are governed by dynamic sorption–desorption equilibria that are sensitive to environmental stressors such as temperature fluctuations, UV radiation, and redox conditions. Addressing these challenges requires innovative approaches and solutions supported by multidisciplinary research and expertise.

Given that MPs transport other contaminants through their physicochemical properties—such as hydrophobicity—degradation processes, including weathering and adsorption, can influence the transformation of adsorbed contaminants. Climate-driven aging processes modify MP surface chemistry, porosity, and functional groups, thereby altering contaminant binding strength and release behavior. A recent study [3] examined degradation mechanisms and factors affecting contaminant adsorption on MPs. Among commonly studied plastic polymers, PE and PS exhibited high adsorption capacities for antibiotics, perfluoroalkyl compounds, and triclosan [3]. In the presence of multiple contaminants, interaction effects—whether incremental (cumulative increases in effect), additive (combined effects equal to the sum of individual effects), synergistic (combined effects exceeding the sum of individual effects), or antagonistic (one contaminant reducing the effect of another)—can occur. These effects are influenced by factors such as the physicochemical properties of the plastic polymers, including particle size, surface roughness, morphology, and functional groups, as well as climate-related stressors that modify these properties over time [3,19].

Several factors influence the sorption of contaminants onto MPs, as noted in a recent study [3]. These include weathering processes—affected by crystallinity, particle size, age, shape, and color—as well as the physicochemical properties of the polymer (e.g., polarity, pKa) and environmental conditions such as pH, salinity, temperature, dissolved organic matter, and UV exposure. Temperature elevation and increased UV radiation associated with climate change can enhance polymer oxidation, increasing surface polarity and, in some cases, sorption capacity. Among common plastic polymers, polyamide (PA) shows the highest sorption of polar contaminants, including antibiotics and Bisphenol A, compared with PS, polyvinyl chloride (PVC), and PP [3]. As plastics undergo natural aging, their sorption capacity and associated toxicity are expected to change over time. The aging of MPs, driven by climatic factors, modifies their physicochemical properties and alters contaminant sorption behavior, which can either enhance or reduce pollutant retention depending on the environmental context. The lack of standardized analytical methods and sampling protocols for MPs further complicates the assessment of co-existence and the resulting interaction effects in soil, water, and living organisms.

In a recent study, Zhu et al. (2025) [20] examined the fate of MPs in soil–water systems in relation to ecological and human-health risks, with particular attention to the mechanisms driving MP degradation. Climatic factors alter the formation and activity of ROS. These reactive species not only accelerate polymer degradation but may also promote the transformation or release of sorbed contaminants. However, knowledge of the underlying mechanisms, reaction kinetics, and transformation pathways of MPs—especially their effects on the behavior of co-existing contaminants—remains limited.

Climatic factors such as drought, extreme precipitation, and elevated temperatures modify dissolved oxygen levels, pollutant leaching, soil microbial activity, soil organic matter, and clay mineral interactions. These changes can lead to either increased or decreased free radical production, thereby accelerating or slowing MP degradation [20]. Such climate-driven variability also affects contaminant desorption rates, byproduct formation, and subsequent bioavailability. These variations sequentially affect polymer transformation and, consequently, contaminant adsorption and mobility. In addition, climatic conditions including strong winds, heat waves, and precipitation events affect the transport and spatial distribution of MPs across environmental media [12,20].

Key challenges that remain include understanding the long-term persistence of free radicals, determining the fate of MP degradation byproducts, characterizing MP migration within environmental systems, assessing the influence of climatic factors on MP removal processes, developing strategies to mitigate MP-related risks, and evaluating MP toxicity under changing climate conditions [20]. With respect to AR, MPs primarily function as secondary vectors that facilitate microbial attachment, biofilm development, and horizontal gene transfer, whereas the dominant drivers of resistance remain antibiotic inputs to the environment. Recent research on microplastic-associated AR [19,21] indicates that MPs serve as hotspots that facilitate AR development, posing an increasing threat to public health.

AR is largely driven by interactions between MPs and environmental conditions, particularly climate change and co-existing contaminants. Climate-induced stress can intensify these interactions by enhancing contaminant availability and microbial activity on MP surfaces. Critical drivers include the large surface area of MPs, which promotes biofilm formation—a process intensified by extreme climate-related events. Additionally, contaminants such as heavy metals and organic pollutants (e.g., pesticides, non-antibiotic pharmaceuticals) further promote AR through mechanisms such as co-resistance, cross-resistance, and horizontal gene transfer [21].

As antibiotic-resistant bacteria (ARB), pathogens, and contaminants enter the water column, MPs interact with them and facilitate biofilm formation, contributing to the development of the plastisphere. At the cellular level, three key processes occur: bacterial colonization of MP surfaces, shifts in microbial community composition, and the transport of pathogenic bacteria. Resistance mechanisms emerge through the enrichment of antibiotic-resistant genes (ARGs) and the proliferation of resistant strains [21]. Climate-related stressors may further enhance these processes by altering microbial metabolism and selection pressures. Together, these processes heighten ecological risks through complex environmental interactions and increase the persistence and resilience of bacterial communities [21].

Among the various contributors to pollution, environmental sources of MP contamination include high-risk pollutants—such as organic contaminants, antibiotics, heavy metals, and pesticides—as well as bacterial communities, including ARB carriers (e.g., E. coli, Pseudomonas, Actinobacteria) and pathogenic species (e.g., Vibrio spp., Salmonella) [21]. MPs exposed to these pollutants and microbial communities are subsequently released into environmental media such as aquatic systems (freshwater, marine environments, sediments) and agricultural settings (surface soils, farming areas). Their presence in these pathways poses public health risks through exposure routes including inhalation, dermal contact, and ingestion of contaminated food.

Several studies have demonstrated that climate change and plastic pollution are interconnected, jointly contributing to the emergence of new contaminants—particularly the evolution of AR associated with MPs. However, limited research has explored the mechanistic links between climate-driven MP transformation, contaminant persistence, and ecological impacts, as well as their effects on ecosystems and soil microbial communities. Addressing this knowledge gap is essential for developing effective mitigation strategies within the climate change–microplastic nexus.

4. Remedial Strategies for Plastics in Tackling Public Health Challenges

Recent studies highlight a range of remedial approaches for managing plastic waste, including its conversion into activated carbon, green energy, wood–plastic composite materials, and construction bricks [22,23,24,25]. This section outlines the role of plastic-waste valorization within a circular economy framework as part of broader mitigation strategies and discusses the associated challenges and environmental trade-offs in reducing risks to public health and the environment.

Plastic waste presents an increasingly serious problem due to the toxicity of microplastic particles, their capacity to adsorb harmful contaminants, and the lack of effective disposal methods to prevent long-term environmental and human health impacts, as documented in several health-focused reviews highlighting inflammation, oxidative stress, and organ-specific effects associated with microplastic exposure [9,26,27]. In response, efforts are underway to convert plastic waste into value-added materials that can be used for wastewater remediation. Because most plastic waste ultimately accumulates in landfills—and considering both the limited availability of landfill space and the high costs of disposal—circular-economy approaches that prioritize resource recovery, reuse, and conversion are being advocated to reduce waste burdens and facilitate the treatment of contaminants associated with discarded plastics.

One promising approach involves producing activated carbon from plastic waste. Activated carbons generated from plastic-waste-derived chars have shown surface areas ranging from 0.2 to 2152 m²/g, with variability arising from differences in plastic feedstock, activation method (physical or chemical), and process conditions such as temperature and activation time. These materials exhibit strong performance in removing emerging contaminants of concern, although their capacity for heavy metal removal is generally lower [22]. From a conceptual standpoint, this approach closes material loops by transforming waste plastics into functional sorbents. Additional research is needed to address limitations such as potential leaching, limited reusability, and production costs. Carbon-based materials produced from plastic-waste feedstocks have broad applications, including water treatment, sensors, solar cells, energy storage, electrochemical devices, and membrane separation technologies [22].

The efficiency of contaminant removal by activated carbon derived from plastic waste depends on environmental conditions and the extraction methods employed. Factors such as initial pH, contaminant concentration, temperature, and contact time should be carefully evaluated to optimize performance. From a circular economy perspective, converting plastic waste into activated carbon is a recommended strategy. because it reduces landfill disposal while generating high-value remediation materials. In a recent study, plastic waste was also explored as a feedstock for green energy production [23]. This approach offers an environmentally sustainable solution, simultaneously reducing the burden of plastic pollution and contributing to climate mitigation efforts. Plastic waste-derived carbon materials (PWCMs) demonstrate high specific surface area, structural stability, and versatile surface chemistry, making them suitable for a range of applications [23].

The study demonstrated that PWCMs are effective in removing emerging contaminants, including antibiotics, polycyclic aromatic hydrocarbons (PAHs), endocrine-disrupting chemicals, heavy metals, and anions. Beyond wastewater treatment, PWCMs also show potential for CO₂ adsorption, contributing to global warming mitigation and sustainability. The CO₂ capture process involves pyrolysis and carbonization, which activate the materials for carbon-based applications. Overall, PWCMs offer a low-cost, potentially lower-carbon, and high-performance alternative to coal, supporting sustainable green energy initiatives [23]. Nevertheless, pyrolysis-based conversion processes may generate secondary emissions and residues that require careful environmental management.

Additionally, upcycling plastic waste still requires further investigation, particularly in evaluating its applications, optimizing processes, and assessing limitations with an emphasis on cost-effective and environmentally sustainable approaches. The negative impacts of plastic waste worsen over time due to the accumulation of MPs, the lack of standardized methods for their analysis and quantification, and the inadequacy of traditional treatment methods, such as incineration and landfilling, to address associated contaminants. Improper or poorly controlled conversion processes may also exacerbate environmental harm by releasing toxic pollutants and additives from degrading plastics, disrupting ecosystems, and posing risks to public health. Importantly, these valorization strategies may also introduce secondary risks, including energy consumption, GHG emissions, and potential release of residual pollutants during processing. A critical assessment of these trade-offs is necessary to ensure that the environmental benefits of plastic upcycling outweigh associated impacts.

An alternative approach involves using plastic waste to produce wood–plastic composite products for construction, with higher proportions of recycled plastic [24]. However, incorporating plastic waste into construction bricks has been linked to occupational health and environmental risks, underscoring the importance of regulatory compliance with workplace safety standards and environmental protection measures [25]. Few studies have thoroughly assessed the human and environmental hazards associated with brick production from plastic waste. The manufacturing process—including collection, sorting, washing, drying, shredding, melting or extrusion, cooling, and molding—can release air pollutants such as heavy metals, organic compounds, particulate matter, and volatile contaminants, posing risks to workers [25]. These risks highlight the need for life-cycle-based risk assessment when promoting plastic-derived construction materials.

Microplastics are widely present not only in water but also in soils and sediments. However, the relative importance of MPs compared to other environmental media, such as water and sediment, should be considered. While microplastics can serve as vectors for contaminants, their contribution to overall environmental and human exposure may vary depending on concentrations, particle size, and co-occurring contaminants. Therefore, assessing pollutant release across different media and life-cycle stages provides a more comprehensive evaluation of public health risks.

Small-scale recycling plants that produce bricks from plastic waste appear to be both economical and effective, particularly in communities or countries with limited disposal infrastructure. However, few studies have evaluated potential occupational hazards, environmental impacts, and pollutant accumulation across the plastic life cycle, especially during the manufacture of products from recyclable and non-recyclable waste. Future research should focus on process optimization to minimize pollutant release and on characterizing the types and concentrations of pollutants and GHG emissions generated during plastic product manufacturing to ensure that circular solutions do not introduce new environmental burdens.

Notably, MNPs have also been detected in food products. Wang et al. (2023) [28] investigated MNPs in food systems, examining their formation, composition, and impacts on food production, processing, and consumption. While MNP detection is well established, information on their distribution, toxicity in combination with environmental contaminants, and remedial approaches remains limited. MNPs can accumulate in the human body through ingestion, dermal contact, or inhalation, resulting in combined toxicity from associated contaminants, including antibiotics, PAHs, pesticides, herbicides, pathogenic bacteria, and heavy metals. Such combined toxicity may arise from additive, synergistic, antagonistic, or potentiating effects [28].

Various remedial approaches have been proposed for MNPs, including filtration (direct and multistage), physico-chemical precipitation, adsorption, and degradation methods such as photocatalysis and biodegradation. However, challenges remain, including the need for efficient and cost-effective remediation techniques, rapid and reliable field detection methods, toxicity assessment of co-existing contaminants under climatic influences, development of biodegradable plastics as alternatives to conventional plastics, removal strategies for both non-biodegradable and biodegradable plastics, and the advancement of enzymes or microbes capable of degrading plastics.

Table 1. Remedial Strategies for Plastic Waste and Public Health Implications.

Strategy	Description/Key Findings	Benefits	Challenges/Public Health Implications	References
Plastic waste valorization (general)	Plastic waste converted into activated carbon, green energy, wood–plastic composites, and bricks.	Reduces landfill burden; supports circular economy; produces value-added materials.	Microplastic toxicity; contaminant adsorption; inadequate disposal methods.	[22,23,24,25]
Activated carbon from plastic waste	Activated carbons show surface areas of 0.2–2152 m2/g; effective for emerging contaminants.	High removal efficiency; broad applicability in water treatment, sensors, energy storage.	Low heavy-metal adsorption; possible leaching; limited reusability; cost barriers. In addition to cost constraints, the large-scale deployment of activated carbon derived from plastic waste is challenged by scalability issues, including feedstock heterogeneity, high energy demands during activation, process integration with existing industrial infrastructure, and the need to ensure consistent material performance at commercial production levels.	[22]
PWCMs for green energy PWCMs for CO2 capture	Plastic waste used as feedstock for high-surface-area carbon materials. Carbonization/pyrolysis produces materials effective for CO2 adsorption.	Eco-friendly; supports energy storage and electrochemical applications. Low-cost, sustainable alternative to coal; climate mitigation support.	Process optimization and environmental impact evaluation needed. Requires performance validation in real environmental settings.	[23]
Wood–plastic composites	Recycled plastics incorporated into composite construction materials.	Reduces waste; durable building applications.	Limited research on emissions, safety, life-cycle hazards.	[24]
Plastic waste bricks	Bricks manufactured by shredding, melting, extrusion, and molding plastic waste.	Cost-effective for small communities; supports areas lacking waste infrastructure.	Releases pollutants (heavy metals, VOCs, PM); occupational health risks.	[25]
MNP remediation methods	Filtration, precipitation, adsorption, photocatalysis, biodegradation.	Multiple promising removal pathways.	Need cost-effective techniques, rapid detection, toxicity assessments, improved biodegradation.	[28]

summarizes the remedial strategies for plastic waste, along with their benefits and the associated challenges for public health.

Despite the promise of plastic-waste valorization and remediation strategies, substantial uncertainty and variability persist across reported findings. Removal efficiencies for contaminants using plastic-waste-derived activated carbon and related materials vary widely depending on feedstock composition, production conditions, activation methods, and environmental parameters, complicating cross-study comparisons. Moreover, many studies are conducted under controlled laboratory conditions, and reported performance may not translate directly to field-scale or long-term applications. Conflicting evidence also exists regarding the environmental trade-offs of upcycling approaches, particularly when energy-intensive processes, potential contaminant leaching, or secondary emissions during production are considered.

For construction and composite applications, data on occupational exposure, life-cycle emissions, and microplastic release during manufacturing and use remain limited. Similarly, although the occurrence of micro- and nanoplastics in food systems is increasingly documented, toxicological outcomes—especially under combined exposure to co-contaminants and varying climatic conditions—are still poorly constrained. Collectively, these uncertainties underscore the need for standardized methodologies, long-term field studies, and comprehensive life-cycle assessments to robustly evaluate the net benefits and risks of proposed remedial strategies.

Remedial Strategies for Addressing MPs in Waterways

Climate change–driven storms have contributed to MP pollution, particularly in urban stormwater systems, where MPs are increasingly detected—most notably from tire wear particles [29]. Friction between tires and pavement generates these particles, which accumulate on road surfaces and are subsequently washed into stormwater systems during rainfall events, degrading water quality and impacting aquatic ecosystems. Wolfand et al. (2023) [29] reported that a substantial portion of MP pollution originates from urban stormwater. However, many existing stormwater management systems lack the infrastructure to effectively capture and filter MPs before they are discharged into rivers and lakes. This deficiency poses risks to both environmental and human health, as MPs can persist in the environment, bioaccumulate through aquatic food webs, and potentially contaminate drinking water sources [30].

To mitigate MP pollution in urban stormwater, three filtration systems—bioretention cells, sand filtration, and constructed wetland filtration—have been evaluated based on cost, environmental impact, maintenance requirements, removal efficiency, social acceptability, and land use [31]. These systems are essential for preventing MPs and other pollutants from entering larger water bodies, including rivers and oceans, thereby promoting cleaner and healthier aquatic ecosystems.

Bioretention cells are shallow depressions filled with media such as sand, compost, soil, or proprietary mixtures, typically covered with vegetation or mulch [32]. Runoff water infiltrates the surface, is filtered through the media, and the treated water is conveyed to a stormwater drainage system. Sand filtration, a widely applied method, directs water through a sand layer that traps pollutants. Recent studies have shown that MP removal rates of up to 99% can be achieved using a horizontal flow design, in which water flows laterally across the sand bed rather than vertically, allowing MPs to be retained within the sand and removed during maintenance [33].

Constructed wetlands (CWs) are engineered systems designed to mimic the functions of natural wetlands, removing substantial amounts of pollutants from water primarily through plant uptake and contaminant retention. Among the three stormwater filtration systems, CWs offer several advantages, including high efficiency (>95%) in MP removal and support for biodiversity [31]. In comparison, sand filters can be costly and require frequent maintenance, while bioretention cells demand more land and may encounter long-term soil issues. Consequently, CWs provide an effective balance between performance and practicality. These systems represent a sustainable and eco-friendly approach, employing layers of soil, sand, and vegetation to naturally filter stormwater.

Additional features, such as trash-capture devices and sponge-based technologies, can further enhance the ability of CWs to remove smaller plastic particles [31]. Regular dredging prevents the accumulation of sediments, MPs, and other pollutants, while ongoing plant monitoring and replacement ensure that trapped plastics are not re-released into the environment.

Beyond improving water quality, CWs contribute to urban resilience by mitigating flooding, reducing pollution, creating green spaces, and enhancing residents’ quality of life. They also offer educational opportunities that emphasize the importance of environmental protection. The development and integration of such filtration systems into urban drainage infrastructure are therefore critical for safeguarding water quality and promoting healthier ecosystems in the face of increasing global plastic production and pollution.

Despite the notable advantages of CWs over other filtration systems, several challenges remain. These include the absence of standardized methods for detecting and analyzing MPs, limited understanding of system lifespan and maintenance needs (e.g., dredging, plant and sponge replacement), uncertainties regarding risk mitigation and plastic recycling, questions about the long-term efficacy of CW treatment, and potential adverse effects on humans, animals, and the environment.

5. Conclusions

This review highlights several key scientific insights regarding the interconnected roles of MPs, climate change, and environmental and public health risks. First, MPs and climate change are not independent stressors but interact bidirectionally: climatic factors such as temperature, UV radiation, and extreme weather events influence MP degradation, transport, and toxicity, while plastic production, degradation, and management contribute to GHG emissions. Second, as plastics weather and transform, they act as dynamic carriers of co-existing contaminants, including emerging contaminants of concern, whose sorption, release, and toxicity are strongly modulated by environmental and climatic conditions. These interactions underscore the need to treat MPs as active components of complex socio-environmental systems rather than inert pollutants.

Despite growing attention to plastic pollution, significant research gaps remain. In particular, there is limited understanding of the long-term environmental behavior and health impacts of transformed plastics and plastic-derived byproducts, especially those generated through recycling, upcycling, or alternative material pathways. The potential release of toxic additives, degradation products, or newly formed contaminants during plastic conversion and reuse processes remains underexplored. Moreover, current studies often assess MPs or associated contaminants in isolation, insufficiently capturing mixture effects, chronic exposures, and climate-driven variability.

Priority future research should therefore focus on integrated, life-cycle–based assessments that link plastic production, use, transformation, and end-of-life management under changing climatic conditions. Key directions include (i) systematic evaluation of the toxicity and environmental fate of plastic alternatives and value-added conversion products; (ii) identification of processing and manufacturing parameters that minimize pollutant release and secondary risks; and (iii) development of standardized methods to assess combined effects of MPs, co-contaminants, and climate stressors. Addressing these priorities will be essential for informing circular economy strategies that are not only resource-efficient but also environmentally safe and resilient to future climate change.

Figure 2 summarizes the reviews presented in Section 2, Section 3 and Section 4 and highlights future research directions.