Microplastics, Volume 4, Issue 1 (March 2025) – 13 articles

Microplastics pose a significant environmental threat, and understanding their sources and generation mechanisms is crucial for mitigation efforts. This study investigates the effects of ultraviolet intensity, temperature, and relative humidity on the degradation of polyethylene terephthalate (PET) plastics and the subsequent formation of microplastic particles. PET samples were exposed to ultraviolet (UV) radiation under various environmental conditions using the SPHERE (Simulated Photodegradation via High Energy Radiant Exposure) accelerated weathering device at the National Institute of Standards and Technology (NIST). Attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR) and laser confocal scanning microscopy (LSCM)/atomic force microscopy (AFM) were employed to characterize the chemical and morphological changes on the weathered surfaces. This study’s findings reveal that temperature and relative humidity significantly influence the rate of photodegradation and the characteristics of the generated microplastics. Higher temperatures and increased humidity accelerated the degradation process, leading to a higher abundance of microplastic particles. However, larger particles were observed at higher temperatures due to aggregation. These results underscore the importance of considering environmental factors when assessing the fate and transport of microplastics in the environment. Developing strategies to reduce plastic pollution and mitigate the generation of microplastics is essential for protecting ecosystems and human health. Full article

This study focuses on the deposition of microplastics (MPs) on urban beaches along the central São Paulo coastline, utilizing advanced methodologies such as remote sensing, GNSS altimetric surveys, µ-Raman spectroscopy, and machine learning (ML) models. MP concentrations ranged from 6 to 35 MPs/m², with the highest densities observed near the Port of Santos, attributed to industrial and port activities. The predominant MP types identified were foams (48.7%), fragments (27.7%), and pellets (23.2%), while fibers were rare (0.4%). Beach slope and orientation were found to facilitate the concentration of MP deposition, particularly for foams and pellets. The study’s ML models showed high predictive accuracy, with Random Forest and Gradient Boosting performing exceptionally well for specific MP categories (pellet, fragment, fiber, foam, and film). Polymer characterization revealed the prevalence of polyethylene, polypropylene, and polystyrene, reflecting sources such as disposable packaging and industrial raw materials. The findings emphasize the need for improved waste management and targeted urban beach cleanups, which currently fail to address smaller MPs effectively. This research highlights the critical role of combining in situ data with predictive models to understand MP dynamics in coastal environments. It provides actionable insights for mitigation strategies and contributes to global efforts aligned with the Sustainable Development Goals, particularly SDG 14, aimed at conserving marine ecosystems and reducing pollution. Full article

Microplastics (MPs) are currently a serious environmental problem, primarily due to their persistence in the environment, low concentration, and difficulty in detection and disposal. MPs have also been detected in humans and have been shown to be harmful. Although there are methodologies for their recovery or elimination in most water treatment plants, a significant portion still bypasses these elimination systems. It is this percentage that we must try to eliminate. In addition to finding new methodologies for the treatment of MPs, it is important to find new materials adapted to this process. In this context, metal–organic frameworks (MOFs) are high-versatility compounds that can be synthesized using different techniques to obtain materials with different properties, such as porosity, morphology, conductivity, etc. These materials can adsorb MPs in different ways, such as electrostatic interaction, bond formation, etc., or they can be obtained by containing metals that catalyze reactions for the formation of highly reactive species that can oxidize the MPs. This review examines how MOF materials have gained attention for the adsorption-based recovery and removal of MPs and discusses the problems associated with these materials and possible solutions. Full article

Microplastics, remnants of macroplastics that have broken down to fragments smaller than 5 mm, and nanoplastics, broken down even further to sizes < 1 μm, are pervasive in aquatic ecosystems. These plastic particles are consumed by microscopic organisms, leading to bioaccumulation up trophic levels. The accumulation of plastic in the organismal gut can result in various repercussions, including cellular contamination and genomic modifications such as DNA methylation. While methylation has been studied in teleost fishes, the impact of nanoplastic exposure on this process in any species remains largely unexplored. This study delves into this largely uncharted territory, investigating the accumulation of methylation due to nanoplastic exposure within the genome of cultured bluegill BF-2 cells (Lepomis macrochirus) using methylation-sensitive AFLPs. The methylation state was analyzed through capillary gel analysis and electropherograms. Differential methylation occurred between several control and experimental groups due to nanoplastic exposure; however, these differences were not dose- or time-dependent. These results could suggest that higher dosages and exposure times to nanoplastics do not result in increased methylation levels in congruence with the dosage and exposure time; rather, only the presence of nanoplastics is enough to cause DNA methylation changes. Full article

Rivers are recognized as major unilateral pathways of microplastic transport between terrestrial and marine ecosystems, yet our understanding of their dispersal patterns over space and through time as they migrate from source to sink is limited. In this study, surface water samples were collected monthly from 12 sites along an urban ephemeral river (Leon Creek) in San Antonio between June 2021 and May 2022 to characterize and evaluate the spatiotemporal distribution of microplastics. Microplastics were found in all sites throughout the monitoring timeframe. The mean abundance of microplastics varied from 3.21 to 26.8 items/L. Surface waters consistently contained microplastics during months of dysconnectivity, suggesting atmospheric deposition as a considerable contributive variable. Contrary to prior studies of perennial systems, ephemeral pools and reaches showed no correlation between MP concentration and season precipitation. Fibers were the most abundant (~87%) morphology followed by foams (7%). This study is the first to report microplastics in ephemeral streams, suggesting that different environmental variables may be responsible for microplastic dynamics in intermittent river and ephemeral stream systems and headwater tributaries of major rivers. As the global extent of IRES systems is projected to increase with continued climate change, understanding such systems’ influence on MP spatial distribution and fluvial transport regimes constitutes valuable information in assessing MP pathways and their fate as a part of the global “Plastisphere” geochemical cycle in the Anthropocene. Full article

Rubber materials enter aquatic environments by stormwater runoff via sources such as playground mulch, athletic fields, and roadway surfaces. Tire rubbers are considered plastics as they comprise a substantial portion of synthetic polymers. Rubber particles are complex and variable depending on the type, source, and age of rubber. In this study, zebrafish embryos and daphnids were exposed to nano-scale or micro-scale particles, or leachate from recycled rubber (RR), crumb rubber (CR), and cryo-milled tire tread (CMTT). Zebrafish embryos were evaluated for lethal and sub-lethal effects over a 120 h exposure, while daphnids were tested over a 48 h period. Nano-scale RR, CR, and CMTT particles elicited a hatch delay in zebrafish embryos with similar EC₅₀ values (1.3 × 10⁹–1.4 × 10⁹ particles/mL). Micro-scale particles did not elicit any significant effects in developing zebrafish. Nano-scale particles of all rubber materials significantly increased hatch delay compared to leachate, suggesting an adverse nanoparticle effect unexplained by chemical leaching alone, indicating tire particle-specific effects. Daphnia RR micro- and nanoparticle exposures resulted in mortality, with LC₅₀ values of 9.8 × 10⁵ microparticles/mL and 5.0 × 10⁸ nanoparticles/mL, respectively. Leachate exposures did not elicit significant Daphnia mortality. Sublethal micro- and nano-TP exposures significantly decreased microalgae ingestion by Daphnia after 24 h. The effects of tire-derived exposures observed pose a risk to aquatic organism survival at environmentally relevant concentrations. Full article

Biodegradable materials are emerging as a sustainable alternative to conventional petroleum-based plastics across packaging, sanitation, and agriculture sectors. These materials naturally decompose into harmless substances within a specified period, completing an eco-friendly lifecycle. However, the widespread adoption of biodegradable plastics depends on building confidence among consumers, manufacturers, and regulators regarding their effectiveness. This study employed a mixed-methods approach to investigate the key factors influencing biodegradable plastics’ sustainability, integrating theoretical frameworks with survey data collected from Malaysian plastic users aged 15 and above. Results revealed that individual characteristics, particularly environmental self-identity, significantly influence behavioural intentions toward sustainable practices, such as choosing eco-friendly packaging. The findings contribute to the theoretical understanding of biodegradable plastics adoption in developing markets while providing actionable insights for government and corporate stakeholders. This study recommends targeted awareness campaigns emphasising environmental self-identity to reduce conventional packaging use and promote biodegradable alternatives. By incorporating these identity-focused messages into marketing communications, organisations can enhance public awareness and market perception of biodegradable products. Full article

Microplastics (MP) are ubiquitous contaminants in diverse environmental matrices, including biota. Urban birds, such as pigeons (Columba livia), are particularly vulnerable to MP exposure due to their scavenging habits and proximity to human activities. This study developed and applied a methodology to assess MP presence in pigeon feces, starting with a review of existing methods for extracting MPs from organic matrices. Of all the methodologies investigated, a method was established to be tested, varying the reagent, using pigeon feces collected from the Universidad Autónoma Metropolitana, Azcapotzalco Unit (UAM-A) and 15 virgin microplastics of five different types. Of both reagents, it was found that the method with 50% H₂O₂ presented better results (degradation of almost all organic matter and recovery efficiency of 93.33%). The selected method was optimized before being applied to feces collected from three sites in Mexico City (n = 10 samples per site). MPs were extracted using a digestion process with 50% hydrogen peroxide, flotation test with CaCl₂, staining with red Nile dye and vacuum filtration and analyzed by microscopy and FTIR. Concentrations ranged from 16.4 to 27.8 MP/g dry feces, with fragments (80%) and fibers (20%) being the predominant shapes. The most common colors were black (32%) and white (22%), the polymers identified included polystyrene and polyethylene and the most common size was < 1 mm (54%). These findings suggest that pigeons ingest MP during feeding, likely due to confusion with organic matter, highlighting the risks of urban plastic pollution to avian health. The ingestion of MPs could lead to malnutrition, organ damage, and ecosystem imbalances, underscoring the need for improved waste management in urban areas. This study provides evidence of the pervasive impact of plastic pollution in non-marine environments, demonstrating the potential of urban birds as bio-indicators of local contamination. Full article

Microplastics (MPs) are plastic particles ranging from 1000 to 5000 µm in diameter, posing a growing environmental and health risk. Composting is an excellent way to add nutrient-rich humus to the soil to boost plant development, but it also pollutes agricultural soil with MPs. Previous research has shown that MPs can threaten plant development, production, and quality, hence they must be studied. This study examined how a mixture of three MP types—polyethene (PE), polystyrene (PS), and polypropene (PP)—affected greenhouse tomato plant development. MP types were spiked at 1% w/w (MPs/soil) in tomato pots, whereas non-spiked growth medium was the control. Statistical analysis was conducted using an analysis of variance (ANOVA) and Tukey’s test (95% confidence) to compare treatments and controls. Soil spiked with MPs increased chlorophyll content (SPAD), transpiration rate, photosynthetic rate, and stomata conductance by 5.16%, 16.71%, 25.81%, and 20.75%, respectively, compared to the control but decreased sub-stomata CO₂ concentration by 3.23%. However, MPs did not significantly affect tomato plant morpho-physiological features (p > 0.05). Biochemical analysis of tomato fruits showed significant (p < 0.05) reduction effects of MPs on carotenoid, total flavonoid, and sugar but increased protein, ascorbate, and peroxidase activity. However, there was no significant difference (p > 0.05) in the effects of the combined MPs on total phenolic content. These data imply that whereas MPs did not influence tomato plant physiological and morphological properties, tomato fruit biochemistry was reduced. This raise concerns that an increase in MPs in soils may reduce antioxidant content and negatively affect human health contributing to a decrease in food security. Full article

Micro-nano plastics (MNPs) are emerging environmental and food contaminants that are raising serious health concerns. Due to the polycontamination of the food web with environmental pollutants (EPs), and now MNPs, the co-ingestion of EPs and MNPs is likely to occur, and the potential synergistic effects of such co-ingestions are completely unstudied. In this study, we therefore sought to determine the effects of the two model EPs, arsenic and boscalid, on the uptake and toxicity of two model MNPs, 25 and 1000 nm polystyrene (PS-25 and PS-1000), and vice versa, employing a triculture small intestinal epithelium model combined with simulated digestion. In 24 h triculture exposures, neither MNPs, EPs, nor MNPs + EPs caused significant toxicity. The presence of PS-25 significantly increased arsenic uptake (from 0.0 to 5.8%, p < 0.001) and translocation (from 5.2 to 9.8%, p < 0.05) but had no effect on boscalid uptake or translocation, whereas PS-1000 had no effect on the uptake or translocation of either EP. The uptake of both PS MNPs was also increased by EPs, rising from 10.6 to 19.5% (p < 0.01) for PS-25 and from 4.8 to 8.5% (p < 0.01) for PS-1000. These findings highlight the need for further studies to assess MNP-EP interactions and possible synergistic adverse health impacts. Full article

Technical retrofit Sustainable Drainage Systems (SuDSs) are a suitable option in the numerous mitigation measures to reduce the amount of tyre wear entering the environment. In the study presented here, such a filter system was tested under extreme conditions at the ADAC Driving Safety Centre Berlin-Brandenburg. Despite a technical separation limit of 125 or 250 µm of the filter systems, particles > 6 µm were measured in the retained masses. In addition, the marker SBR was used to determine the residues of tyre wear in the filter system using the TED-GC-MS analysis method. The highest concentrations were found in the 20–63 µm fraction. The results indicate that tyre wear particles become smaller due to high forces generated by braking and cornering. Test stand investigations indicate a retention efficiency of the filter system of 2/3 of the tyre wear. Furthermore, the results show that the parameter ‘Total Suspended Solids < 63 µm’ (TSS₆₃) is a relevant evaluation parameter for the road runoff. Full article

This study addresses the pressing need for standardized methodologies to quantify microplastics (MPs) within the fine fraction of municipal solid waste (MSW), often overlooked despite its potential environmental impact. Five extraction protocols were evaluated to identify the most effective method for isolating MPs in fine waste. These were specifically applied to samples from the Universidad Autónoma Metropolitana and one transfer station in Mexico City. A potassium hydroxide digestion protocol with subsequent flotation and centrifugation steps achieved optimal results, ensuring complete organic matter degradation and high microplastic recovery. Subsequent analyses revealed notable concentrations of MPs, primarily fragments and fibers, with higher abundance at the university site. Statistical tests confirmed significant differences between the sample sites. These findings highlight the vulnerability of MSW fine fractions to microplastic contamination and underline the importance of targeted waste management strategies. This research contributes to understanding microplastic behavior in waste management systems and emphasizes the need for mitigation efforts to prevent environmental contamination. Full article

Nanoplastics (NPs) and microplastics (MPs) are an emerging threat to global health. They negatively impact ecosystems and many physiological processes, causing alterations in xenobiotic metabolism, nutrient uptake, energy metabolism, or cytotoxicity. In humans, we are beginning to analyze these plastics for the mechanisms by which they enter the organism, accumulate, and diffuse as well as for their pathogenic potential. NP accumulation has been demonstrated in human tissues, such as blood or placenta, while in others it remains largely unstudied. In this work, we detected NP accumulation in bronchoalveolar lavage fluids (BALFs), cerebrospinal fluids (CSFs), lymph nodes (LNs), urine, pleural fluids (PFs), ascitic fluids (AFs), and peripheral blood (PB) by combining fluorescence and nanocytometry techniques. NP analysis was compared with two strains of mice, and the results support that inhalation is the main route of NP accumulation. Full article