Effects of microplastics on the terrestrial environment: A critical review

Ecotoxicological impacts of polyethylene, polystyrene and polyamide on the land snail Cantareus aspersus in a life cycle experiment

Small plastic fragments (<5 mm, i.e., microplastics, MPs) accumulate in ecosystems, resulting in increasing concerns about their toxic effects in the terrestrial environment. While studies on MPs in the soil environment are expanding, gaps in knowledge still exist regarding their effects on soil (macro)organisms. Our study aimed to measure the response of Cantareus aspersus snails to long-term exposure to 0.1, 1 and 10 % w/w polyethylene (PE), polyamide (PA) or polystyrene (PS) particles in food. Overall, a concentration-dependent decrease in snail growth was observed, as was a general trend toward earlier maturity at low and middle MP concentrations. Mild (for PS) to severe (for PE and PA) effects on reproduction were detected but without a concentration-dependent trend. The fecundity was affected mainly by PE at 1 % (-32.9 %) and by PA at 1 % (-52.59 %), and their fertility was reduced by 43.9 % and 61.3 %, respectively. This decrease was related to increased survival, suggesting trade-offs in snail energy allocation and/or endocrine regulation. This study revealed that an environmentally relevant life-cycle assessment of toxic effects allows the detection of subtle effects regarding individual responses. These effects allowed us to demonstrate differential impacts on animal health status according to the polymer used and the exposure concentration.

Omaveloxolone Prevents Polystyrene Microplastic-Induced Ovarian Granulosa Cell Apoptosis via the Keap1/Nrf2/HO-1 Pathway in Rats

Microplastics (MPs) are persistent environmental pollutants that enter the circulatory system and subsequently reduce sperm quantity and quality. However, the influence of polystyrene MPs (PS-MPs) on the ovary and relevant mechanisms remain elusive. Herein, we aimed to examine the impact of PS-MPs on oxidative disorders in ovarian tissues and elucidate the underlying mechanisms. Healthy female rats were treated with different concentrations of 0.5 µm PS-MPs (diluted in deionized H2O) for 90 days. Upon examination of hematoxylin-eosin-stained ovarian tissue sections, the number of growing follicles was reduced in PS-MP-treated rats when compared with that in control rats. Enzyme-linked immunosorbent assays revealed that PS-MP exposure markedly reduced anti-Müllerian hormone (AMH) levels. Treatment with PS-MPs downregulated superoxide dismutase, glutathione, and catalase activities in ovarian tissues while upregulating malondialdehyde levels. Furthermore, exposure to PS-MP blocked the Keap1/Nrf2/HO-1 signal transduction pathway. PS-MPs also triggered apoptosis in the ovarian tissue, as evidenced by increased TUNEL staining and expression levels of cleaved caspase-9, Bax, and Bcl-2. To reactivate the Keap1/Nrf2/HO-1 pathway, rats were co-administered PS-MPs and omaveloxolone (Oma), an Nrf2 activator, for 1 week. We found that Oma could counteract the PS-MP-mediated effects on oxidative disorder, apoptosis, AMH production, and follicle number in rat ovarian tissues. To develop an in vitro model, granulosa cells (GCs) were treated with 10 μM H2O2 for 12 h to induce oxidative stress. H2O2-stimulated GCs exhibited attenuated cell growth and upregulated apoptosis and oxidative stress. Oma administration could ameliorate the H2O2-induced effects in terms of regulating cell viability, apoptosis, and oxidative stress in GCs. In summary, PS-MPs could induce apoptosis and oxidative stress via the Keap1/Nrf2/HO-1 signaling pathway in both rats and GCs.

Eco-friendly lily bulb-derived polysaccharide aerogel for efficient microplastics and nanoplastics removal

Microplastics that eventually convert into nanoplastics are emerging global pollutants and the development of efficient adsorbents for their removal is urgently needed. For sustainability and eco-friendliness, in the current study, a polysaccharide aerogel (LPA) was prepared with lily bulbs as the raw material by following water bath extraction, purification and freeze-drying processes. The prepared porous LPA was then applied as a packing material in a mini adsorption column for removing polystyrene (PS) microplastics and nanoplastics. Results revealed that LPA was over 90 kDa in size and consisted mainly of glucomannan and the removal efficiencies for microplastics and nanoplastics were 93.68 % and 96.98 %, respectively, mainly due to hydrogen bonding interactions and porous structure. The adsorption column was robust and maintained a remarkable removal efficiency (over 90 %) for 3 months. In addition, the effects of other extraction methods and pre-freezing conditions before the freeze-drying process were studied. Compared with water bath extraction, ultrasonic-assisted extraction and microwave-assisted extraction transformed the LPA structure, resulting in reduced adsorption ability, while the pre-freezing temperature could be used to adjust the specific surface area. Meanwhile, the effects of temperature and pH of adsorbates were also investigated. The LPA was heat sensitive and not stable under strongly acidic (pH 4) or strongly alkaline (pH 10) conditions, resulting in a sharp decline in removal efficiency. The adsorption behaviour of LPA was further described via adsorption kinetic models, showing that the microplastics and nanoplastics adsorptions could be fitted by pseudo-second-order and pseudo-first-order models, respectively. Moreover, the adsorption performance of LPA was compared with some other aerogels and had a better result. This research provides a promising, sustainable alternative for microplastic and nanoplastic removal that has potential for pollutant adsorption and sample purification as well as a low preparation cost.

Acetochlor promotes the aging of mulch-derived microplastics in soil by altering the plastisphere microbial community

Although many studies have already highlighted the effects of mulch-derived microplastics (MDMPs) on adsorbing and spreading organic pollutants, the ecological risks of MDMPs co-contaminated with herbicide and the interaction between them have not been clarified. In this study, the interactions between MDMPs from virgin and aged low-density polyethylene (LDPE) films and the herbicide acetochlor in soil were investigated by microcosmic experiments. Results showed that acetochlor in soil was significantly enriched on the surface of MDMPs, with higher concentration on aged-MDMPs compared to virgin-MDMPs. Acetochlor significantly accelerated the fragmentation of aged-MDMPs, leading to more oxygenated functional groups and promoting biofilm development. Acetochlor also notably altered plastisphere microbial community, with Pseudomonas dominating for an extended period in acetochlor-treated samples. This suggests that Pseudomonas may facilitate the aging of MDMPs, likely due to its dual ability to degrade both acetochlor and polyethylene. Additionally, acetochlor initially increased microbial diversity and interaction complexity in the plastisphere, but decreased them in later phase, resulting in a more specialized community. These findings reported here broaden our understanding of interactions between MDMPs and herbicide in soil and offer insights for improved farmland management practices.

Assessment of suspended atmospheric microplastics in Tianjin Binhai New Area: characterization, human health risks, and correlation with weather conditions and Air Quality Index

Suspended atmospheric microplastics (SAMPs), as a critical component of environmental microplastic pollution, have garnered substantial scientific interest. The characterization of SAMPs in urban environments, as well as the potential risks on health, continues to be a topic of significant research interest. This study provides a comprehensive report on the presence of SAMPs in the Binhai New Area of Tianjin, China, based on samples collected during the autumn and winter of 2023-2024 using a medium-flow total suspended particulate (TSP) sampler at a monitoring station. Microplastics were detected in all samples, with concentrations ranging from 0.2 to 1.8 items/m3 in autumn and from 0.1 to 1.1 items/m3 in winter, and a total mean of 0.6 ± 0.4 items/m3. Particle sizes spanned 12.28-3248.58 µm, with fibrous shapes dominating the morphological composition. Observed colors included black, blue, yellow, transparent, red, and green, with black microplastics being the most prevalent. These SAMPs were composed of polyethylene terephthalate, polyethylene, rayon, polypropylene, and ethylene-ethyl acrylate copolymer. A risk assessment indicated that residents of Binhai New Area, Tianjin City, face a measurable health risk from microplastic exposure. Significant correlations were identified between SAMPs and dew point temperature as well as relative humidity in the autumn. In the winter, significant correlations were observed between the abundance of SAMPs and ground barometric pressure and wind velocity. Weak negative correlations were observed between SAMP abundances and the Air Quality Index (AQI) in both seasons Future research will utilize more advanced technologies and establish a global monitoring network to further explore the sources, distribution, and impacts of atmospheric microplastics.

Microplastic pollution in the glaciers, lakes, and rivers of the Hindu Kush Himalayas: Knowledge gaps and future perspectives

The Hindu Kush Himalayas (HKH), often referred to as the Third Pole and the Water Tower of Asia, represents a vital geo-ecological asset, providing essential services to millions of people. However, this once-pristine environment is increasingly threatened by the influx of microplastics. This study provides a comprehensive overview of the current state of microplastic pollution in the HKH region, identifies key research gaps, and highlights areas for future research. A review of existing literature reveals the lack of standardized protocols for microplastics analysis, which hinders cross-study comparisons. The reported microplastic abundances vary widely across environmental matrices including 0.14-31,200 MPs m-3 in river water, 0.072-26,000 MPs kg-1 in river sediments, 180-5500 MPs kg-1 in lake sediments, 55-2380 MPs kg-1 in lake shoreline sediments, 30-871.34 MPs L-1 in glaciers, and 2.23-130 MPs L-1 in lake surface water. Polymer characterization using spectroscopic techniques has identified 54 polymer types across different environmental matrices in the HKH region with polypropylene (PP) being the most dominant, followed by polyethylene (PE), and polystyrene (PS). The sources of microplastics in the HKH region include both local activities and long-range atmospheric transport. Although research on microplastics in the region has gained momentum in recent years, significant knowledge gaps remain regarding their fate, degradation mechanisms, and environmental impacts. Further studies are essential to investigate the role of microplastics as light-absorbing impurities that may accelerate glacier melting, as well as their implications for biodiversity and human health in the region.

Assessment of microplastic contamination in compost leachate: insights from a municipal compost plant in Isfahan, Iran

The increasing production of waste has become one of the major environmental challenges of our time, particularly in waste management. While the composting process can transform municipal waste into a valuable product, the presence of plastics and microplastics (MPs) (< 5 mm) in the waste and their integration into the final compost and leachate pose significant environmental concerns. This is the first study to analyze the abundance of MP in the compost leachate from one of the Isfahan compost plant (S1), located in one of Iran's major cities with high population density, during the summer season. MPs were counted using a stereomicroscope, and fourier transform infrared spectroscopy (FTIR) was utilized to identify polymer types. The results revealed an average abundance of MPs in the S1 leachate during the summer of 992.66 ± 100.85 items/L. Over 62% of the MPs identified in this study fell within the 1000-5000 μm size range, with a concentration of 610.28 ± 59.26 items/L. Polystyrene and polyamide emerged as the most frequently identified polymers (18.46% and 16.8%), and fragments were the most commonly observed shape among the MPs. This study underscores that compost leachate contains high concentrations of MPs that can disseminate into various environmental compartments such as groundwater, surface water, soil, and even air. Consequently, compost leachate should be recognized as a significant source of MPs entering the environment.

Low-dose exposure to microplastics retards meiotic maturation via HDAC3 insufficiency

Microplastics (MPs) are considered one of the main causes of male and female infertility. However, the reproductive toxicity and its related mechanisms are currently understood primarily through animal models with acute exposure to MPs. In this study, we demonstrate that low-dose exposure to polystyrene microplastics (PSMPs) leads to severely abnormal reproduction in females, manifested by oocyte meiotic maturation defect. Mechanistically, PSMPs exposure induce the overactivation of cell metabolism pathways, insufficient HDACs, and H4K16 hyperacetylation in oocytes both in vivo and in vitro. When an HDAC3 inhibitor is added, the oocyte maturation defect, overactivation of cell metabolism pathways, and H4K16 hyperacetylation are recapitulated. Conversely, the overexpression of HDAC3 can rescue the defects in meiotic maturation induced by PSMPs. Our observations suggest a direct link between the maturation defects caused by PSMPs and HDAC3 insufficiency. Thus, we propose potential treatments to address the meiotic maturation defect of oocytes in women highly exposed to MPs by activating or supplying HDAC3.

Aerosol mass concentrations and dry/wet deposition of atmospheric microplastics at a remote coastal location in New Zealand

This study quantified airborne microplastic concentrations by mass and number counts using both active and passive sampling at a remote coastal location in Southern New Zealand. Seven polymers were quantified using pyrolysis gas chromatography mass spectrometry (Pyr-GC/MS) in atmospheric samples, finding that plastics comprised at least 0.14 % of total suspended particulate mass at the remote coastal site. Air parcel back trajectories suggest that airborne microplastics at the site, observed at an average concentration of 65 ± 6 ng m-3, have origins from the Southern Ocean. Additionally, the results demonstrate that reporting atmospheric deposition of microplastics by number counts may underestimate the true amount of plastics present in samples, as size limitations associated with microscopic imaging do not allow for quantification of the most abundant sizes and types of environmental microplastics. With current uncertainties related to aerosol formation in the Southern Ocean and the associated impacts on climate forcing, further research is urgently needed on the production of airborne microplastics originating from the Southern Ocean, a possible microplastic reservoir.

Tiny pollutants, big consequences: investigating the influence of nano- and microplastics on soil properties and plant health with mitigation strategies

The impact of nanoplastics (NPs) and microplastics (MPs) on ecosystems and human health has recently emerged as a significant challenge within the United Nations Agenda 2030, drawing global attention. This paper provides a critical analysis of the influence of plastic particles on plants and soils, with the majority of data collected from recent studies, primarily over the past five years. The absorption and translocation mechanisms of NPs/MPs in plants are first described, followed by an explanation of their effects-especially particles like PE, PS, PVC, PLA, and PES, as well as those contaminated with heavy metals-on plant growth, physiology, germination, oxidative stress, and nutrient uptake. The study also links the characteristics of plastics (size, shape, concentration, type, degradability) to changes in the physical, chemical, and microbial properties of soils. Various mitigation strategies, including physical, chemical, and biological processes, are explored to understand how they address these changes. However, further research, including both laboratory and field investigations, is urgently needed to address knowledge gaps, particularly regarding the long-term effects of MPs, their underlying mechanisms, ecotoxicological impacts, and the complex interactions between MPs and soil properties. This research is crucial for advancing sustainability from various perspectives and should contribute significantly toward achieving sustainable development goals (SDGs).

Effects of polyamide microplastics with different particle sizes on the development of silkworm Bombyx mori (Lepidoptera: Bombycidae) and its progeny: A study based on the age-stage, two-sex life table

Influenced by human activities, microplastics (MPs) are widely distributed in terrestrial ecosystems. However, their ecotoxicity remains unclear. Therefore, we assessed the ecotoxicity of polyamide microplastics (PA-MPs) by investigating their toxic effects on the model insect, the silkworms Bombyx mori (Lepidoptera: Bombycidae). In this study, fifth-instar silkworm larvae were fed mulberry leaves treated with PA-MPs for 120 hours, but no changes in mortality rates were observed. However, the body weight, pupal weight, cocoon weight, egg laying amount, and cocoon shell weight in F0 generation silkworms were significantly reduced. This indicates that PA-MPs have sublethal effects on silkworms. To further investigate the effects of PA-MPs on the offspring of silkworms, we applied the age-stage, two-sex life table analysis. We found that in the PA-MPs treatment group, the duration of the larval and pupal stages of F1 generation silkworms was significantly prolonged, while the lifespan of the adults and total longevity were shortened. Meanwhile, the life history parameters (sxj, exj, lx, fxj, lxmx, and vxj values) and population parameters (R0, λ, r, and T) of F1 generation silkworms in the PA-MPs treatment group were also lower than control. This indicates that PA-MPs have transgenerational effects, affecting the growth, development, and reproduction of F1 generation silkworms. Our research findings demonstrate the sublethal and transgenerational effects of PA-MPs on silkworms, providing evidence for their ecotoxicity.

Potential impacts of microplastic pollution on soil-water-plant dynamics

This study was designed to assess the potential impact of microplastic (MP) pollution on soil hydrology, specifically in retaining and releasing moisture. Herein, High-Density Polyethylene (HDPE) MP of different sizes (i.e., 0.5-1, 1-3, and 3-5 mm) and shapes (i.e., fiber, film, and fragment) were evaluated for their effects on water retention curve (WRC) of sandy loam soil, chosen for its agricultural relevance and widespread environmental presence of HDPE. Nine contamination scenarios were simulated with a low MP pollution rate, 0.01% w/w. Van Genuchten models were used to assess plant available water (PAW), wilting point (WP), and water holding capacity (WHC). Results showed that studied MP could significantly affect WRC and PAW mainly by changing WHC rather than WP and that this effect varied with MP shape and size. According to the results, fragment MP had the greatest impact on soil WHC by increasing 36.3%, followed by fibers and films by 19.8% and 15.7%. MP particles significantly increased WHC, while WP remained relatively unchanged. An observed trend indicated that the impact on WHC increased with the size of the MP particles. These findings emphasize the need to manage soil MP pollution to protect plant growth, agriculture, and water dynamics.

Biochar-mediated remediation of low-density polyethylene microplastic-polluted soil-plant systems: Role of phosphorus and protist community responses

While the prevalent utilization of plastic products has enabled social advancement, the concomitant microplastics (MPs) pollution presents a serious threat to environmental security and public health. Protists, as regulators of soil microorganisms, are also capable of responding most rapidly to changes in the soil environment. The amelioration mechanisms of biochar in the soil-plant systems polluted by low-density polyethylene microplastics (LDPE-MPs) and the response of protist communities in the soil-plant systems polluted by MPs remain unclear. In this field experiment, the same concentration of biochar (2 %) was applied to remediate different concentrations (1 % and 10 %) of LDPE-MPs pollution in cherry radish soil. The main results indicate that, when compared with the treatment of applying biochar to address high-level LDPE-MPs polluted soil (BP2), the remediation of low-level LDPE-MPs polluted soil by biochar (BP1) led to a 62.02 % reduction in soil available phosphorus. Meanwhile, the abundance of phoD and the activity of alkaline phosphatase increased by 127.75 % and 22.57 % respectively. Moreover, in contrast to BP2, the root biomass and phosphorus content of cherry radish in BP1 increased by 52.80 % and 42.86 % respectively. For protist communities, their structure, niche width, and assembly were altered. The interaction between biochar and LDPE-MPs influenced phosphorus cycling, and protists were closely associated with these processes. Therefore, soil phosphorus cycling indicators and protist community may be important indicators for biochar amelioration on soil MPs pollution. The study highlights the importance of considering these factors for better farmland management in the context of MPs pollution, which is significant for sustainable agriculture and environmental protection.

Screening method for differentiation of plastic and non-plastic microparticles contaminating store-bought rice

This article presents a simple and low-cost screening method based on optical microscopy and FT-IR spectroscopy for assessing microparticles found in rice. Five brands of rice packed in paper and foil bags from both the European Union (EU) and non-EU region were tested. Microparticles of various shapes have been found in the rice regardless of the packaging type and origin of the rice. The content of microparticles varies depending on the sample, from 2 to even 12 items per 1 g of rice. Overall, the abundance of microparticles is higher in the case of rice packed in foil bags. Not all identified microparticles are microplastics, but those that are microplastics cannot be directly linked to the composition of the rice package. For a cursory analysis aimed at distinguishing the infrared spectra of non-plastic microparticles (i.e. rice, paper or cellulose) from microplastics, it is sufficient only to analyse the absorption bands above 2800 cm-1.

An economical fluorescent method for microplastic detection in soil samples

Microplastics from urban and industrial waste are threatening ecosystems worldwide. Quantification methods for soil samples have been proposed but typically require complex and expensive laboratory procedures, which are not accessible to the public. Therefore, we developed a simplified Nile Red fluorescent dye method with low-budget materials that can be readily used as a stand-alone demonstration or implemented in environmental education modules. The method was validated on commercial coarse-grain sand spiked with microplastics (1-5 mm). Following incubation with Nile Red dye, the analytes were visually inspected using blue light and orange filter glasses and counted by two independent blinded assessors. Detection of particles was close to 100 percent. Four different types of environmental analytes were subsequently tested with this method: urban lake shore sediment, agricultural soil, gardening soil, and soil from a state park. Urban lake shore and garden soil samples showed the highest density of microplastic particles. Large numbers of smaller particles (<1 mm) were also identified and counted in these analytes, with very good reproducibility by the same assessor and replication of the rank order of analytes between two assessors. Visualizing microplastic pollution with this low-cost, scalable method can reach broad sections of educational settings and the broader public and thus raise awareness of the problem of microplastic pollution.

Inhalation of nanoplastics in the mouse model: Tissue bio-distribution and effects on the olfactory system

The impact of plastic fragments on human health is currently under investigation, with nanoplastics (NPs) being particularly concerning due to their small size. This allows them to be inhaled, pass through blood barriers, and reach various organs. In this study, we evaluated the effects of airborne NPs on the mouse olfactory system, which is a primary target of NPs inhalation. Adult mice were exposed to an aerosol solution containing synthetic polystyrene nanoplastics (PS-NPs) labelled with a red fluorophore for 5 h a day over 7 days. Biodistribution analysis revealed that PS-NPs accumulated in tissues, such as brain, lung, adipose tissue, and testicles, but were cleared after one month. This study is the first to investigate the effects of inhaled PS-NPs on the olfactory bulb (OB) and subventricular neurogenesis in adult mice. We observed long-term impairments in olfactory discrimination, decreased neuronal functionality, and pro-inflammatory activation in microglia in OB following PS-NPs exposure. Surprisingly, we noted a compensatory increase in olfactory neurogenesis, although insufficient to counteract the olfaction impairment induced by the PS-NPs. These results provide novel insights into the potential neurotoxic effects of inhaled PS-NPs and emphasize the importance of assessing occupational and environmental exposure to these pollutants.

Microplastic exposure is associated with epigenomic effects in the model organism Pimephales promelas (fathead minnow)

Microplastics have evolutionary and ecological impacts across species, affecting organisms' development, reproduction, and behavior along with contributing to genotoxicity and stress. As plastic pollution is increasing and ubiquitous, gaining a better understanding of organismal responses to microplastics is necessary. Epigenetic processes such as DNA methylation are heritable forms of molecular regulation influenced by environmental conditions. Therefore, determining such epigenetic responses to microplastics will reveal potential chronic consequences of this environmental pollutant. We performed an experiment across two generations of fathead minnows (Pimephales promelas) to elucidate the transgenerational epigenetic effects of microplastic exposure. We exposed the first generation of fish to four different treatments of microplastics: two concentrations of each of pre-consumer polyethylene (PE) and PE collected from Lake Ontario. We then raised the first filial generation with no microplastic exposure. We used enzymatic methylation sequencing on adult liver tissue and homogenized larvae to evaluate DNA methylation differences among treatments, sexes, and generations. Our findings show the origin of the plastic had a larger effect in female minnows whereas the effect of concentration was stronger in the males. We also observed transgenerational effects, highlighting a mechanism in which parents can pass on the effects of microplastic exposure to their offspring. Many of the genes found within differentially methylated regions in our analyses are known to interact with estrogenic chemicals associated with plastic and are related to metabolism. This study highlights the persistent and potentially serious impacts of microplastic pollution on gene regulation in freshwater systems.

Exposure to Nanoplastics During Pregnancy Induces Brown Adipose Tissue Whitening in Male Offspring

BACKGROUND

Polystyrene nanoplastics (PSNPs) have been recognized as emerging environmental pollutants with potential health impacts, particularly on metabolic disorders. However, the mechanism by which gestational exposure to PSNPs induces obesity in offspring remains unclear. This study, focused on the whitening of brown adipose tissue (BAT), aims to elucidate the fundamental mechanisms by which prenatal exposure to PSNPs promotes obesity development in mouse offspring.

METHODS AND RESULTS

Pregnant dams were subjected to various doses of PSNPs (0 µg/µL, 0.5 µg/µL, and 1 µg/µL), and their offspring were analyzed for alterations in body weight, adipose tissue morphology, thermogenesis, adipogenesis, and lipophagy. The findings revealed a notable reduction in birth weight and an increase in white adipocyte size in adult offspring mice. Notably, adult male mice exhibited BAT whitening, correlated with a negative dose-dependent downregulation of UCP1 expression, indicating thermogenesis dysfunction. Further investigation revealed augmented lipogenesis evidenced by the upregulation of FASN, SREBP-1c, CD36, and DGAT2 expression, coupled with the inhibition of lipophagy, indicated by elevated levels of mTOR, AKT, and p62 proteins and reduced levels of LC3II/LCI and Lamp2 proteins in male offspring.

CONCLUSIONS

These findings indicate that gestational PSNP exposure plays a role in the development of obesity in offspring through the whitening of brown adipose tissue, which is triggered by lipogenesis and lipophagy inhibition, providing a novel insight into the metabolic risks associated with gestational PSNPs exposure.

Impact of high-density polyethylene (HDPE) microparticles on soil physical-chemical properties, CO2 emissions, and microbial community in a two-year field trial

Contamination by microplastics (MPs) is a serious problem affecting both aquatic and terrestrial ecosystems, but despite the large number of papers published in recent years, the impact of microplastics (MPs) on soil is still debated. This work aims to evaluate the effects of different amounts (0, 1, 2 % v/v) of high-density polyethylene (HDPE) microparticles (1-0.25 mm in size) on soil properties over time. Specifically, in a field plot experiment lasting about 2 years, treated and control soils were periodically sampled and analysed for their physical (aggregate stability and distribution), chemical (total N, soluble C and N, available P), and soil biochemical (basal respiration, microbial biomass C, enzyme activities, and fatty acid methyl ester - EL-FAME) properties. In addition, CO2 fluxes from soil to atmosphere were measured throughout the experiment. The physical and chemical parameters of the treated soils did not differ significantly from the control soil, whereas specific changes occurred in the biochemical characteristics during the experiment, particularly in the soil treated with the higher dose of MPs. In the early period (21 to 46 days after the treatment), some changes in the microbial community structure were observed for the soil treated with 2 % MPs, suggesting the occurrence of stress conditions for the microbial biomass, likely due to nutrient limitation. After 166 g from the start of the experiment, the 2 % MPs-treated soil showed, other than a lower CO2 flux than the control soil, a reduction of basal respiration together with an increase in actinomycetes and total fungi (both saprophytes and AMF). There was also an increase in C-related enzyme activities one year after treatment with MPs. These latter results suggest that the soil microbial community may be adapting to the new conditions and available energy substrates, which may also indicate the onset of HDPE degradation processes.

The fate of biodegradable polylactic acid microplastics in maize: impacts on cellular ion fluxes and plant growth

The widespread application of biodegradable microplastics (MPs) in recent years has resulted in a significant increase in their accumulation in the environment, posing potential threats to ecosystems. Thus, it is imperative to evaluate the distribution and transformation of biodegradable MPs in crops due to the utilization of wastewater containing MPs for irrigation and plastic films, which have led to a rising concentration of biodegradable MPs in agricultural soils. The present study analyzed the uptake and transformation of polylactic acid (PLA) MPs in maize. Seed germination and hydroponic experiments were conducted over a period of 5 to 20 days, during which the plants were exposed to PLA MPs at concentrations of 0, 1, 10, and 100 mg L-1. Low concentrations of PLA MPs (1 mg L-1 and 10 mg L-1) significantly enhanced maize seed germination rate by 52.6%, increased plant shoot height by 16.6% and 16.9%, respectively, as well as elevated aboveground biomass dry weight by 133.7% and 53.3%, respectively. Importantly, depolymerization of PLA MPs was observed in the nutrient solution, resulting in the formation of small-sized PLA MPs (< 2 μm). Interestingly, further transformation occurred within the xylem sap and apoplast fluid (after 12 h) with a transformation rate reaching 13.1% and 27.2%, respectively. The enhanced plant growth could be attributed to the increase in dissolved organic carbon resulting from the depolymerization of PLA MPs. Additionally, the transformation of PLA MPs mediated pH and increase in K+ flux (57.2%, 72 h), leading to acidification of the cell wall and subsequent cell expansion. Our findings provide evidence regarding the fate of PLA MPs in plants and their interactions with plants, thereby enhancing our understanding of the potential impacts associated with biodegradable plastics.

Toxicological complexity of microplastics in terrestrial ecosystems

Microplastics (MPs), defined as plastic debris, smaller than <5 mm, are viewed as persistent contaminants that significantly modify terrestrial ecosystems and biodiversity by altering soil microbiota, structure, and functions. This paper summarizes MPs' interactions with various pollutants, including heavy metals and pesticides, also addressing socio-economic impacts, such as reduced agricultural yields and threats to regional fisheries. The study emphasizes the need for an on the basis of waste management model to mitigate these effects, advocating for collaborative efforts among stakeholders. Also, interdisciplinary studies incorporating material sciences, ecology, and environmental policy are essential to confront the challenges of MPs to ecological services. Additionally, the review highlights how MPs can serve as vectors for toxins to damage soil health and species survival. The overview underscores a complex interplay between environmental and socio-economic systems, addressing the urgency of harnessing MPs pollution and protecting ecosystem integrity and sustainability.

What Gastroenterologists Should Know About Microplastics and Nanoplastics

Global production and widespread use of plastics are increasing dramatically. With current limited recycling and recovery options, microplastics and nanoplastics (MNPs) persist in the natural environment. Due to their ubiquity, human exposure to MNPs is inevitable. In addition to their inherent toxic effects, MNPs can adsorb harmful contaminants and act as vectors for microorganisms, compounding toxicological effects. After entering the body, bioaccumulation occurs in several tissues and organs, including the liver and the gastrointestinal (GI) tract. Proposed clinical effects of MNP absorption include endocrine disruption, alteration of the GI microbiome, and promotion of chronic inflammatory conditions. MNPs can also influence energy metabolism, activate inflammatory pathways, and increase oxidative stress leading to apoptosis. The GI tract is a major site of bioaccumulation for the MNPs in animals and humans. In this editorial, the current understanding of how MNPs are processed is discussed. Discussion on MNP effects on internal microflora, and their proposed role in developing inflammatory bowel diseases, MNP toxicokinetics, and their significance in health and disease are also reviewed. There is a need to understand the impact of MNP exposure on gut health and gut microbiota and identify current research gaps.

Microplastics in seawater and fish acquired from the corresponding fishing zones of the Baltic Sea

Microplastics in seawater and fish from the Baltic Sea were analyzed. The significant contribution of the study is due to extensive collection of fish and surface water samples from corresponding fishing zones. Microplastics were detected in 100 % of seawater and 61 % of fish samples. The abundances of microplastics were 19,984 ± 8858 items/m3 (seawater) and 3.3 items/fish in the fish organs. The average dimension was 1.08 ± 1.19 mm (seawater), and 0.77 ± 0.84 mm (fish). In 106 out of 178 specimens (61 %), MPs were found in the gills (46 %), digestive tract (38 %), or liver (16 %). Fiber was the most dominant shape found in seawater (91.7 %) and fish (68.3 %), while the dominant color of items was blue. Items were mostly composed of polyethylene (21 %), polypropylene (20 %), cellophane (16 %), polyamide (9 %), and polyacrylate (8 %).

Interaction and bacterial effects of microplastics pollution on heavy metals in hyporheic sediments of different land-use types in the Beiluo River Basin

Microplastics (MPs) pollution is ubiquitous, causing serious ecological damage by threatening the growth and health of living organisms. This study investigated the vertical and horizontal distribution of MPs, MPs-heavy metals (MPs-HMs) accumulation, contamination assessment and microbial biodiversity in hyporheic sediments of different land-use types. MPs abundance in shallow sediments (0-30 cm) was significantly higher than that in deep sediments (30-60 cm), with fewer large MPs in the deep sediments. Blue, fiber, and <500 μm were the dominant MPs types, and polystyrene, polylactic acid, and polyvinyl chloride were the dominant polymers in the Beiluo River Basin. The average concentrations of HMs detected in MPs were all much higher than the same metals in the sediments. The pollution loading index of MPs was higher in areas with a greater proportion of anthropogenic land use, and MP-HM were present to varying degrees in the vertical distribution (PN > 1). Critically, bacterial diversity of anthropogenic land use was smaller than that of natural land use. High MP-HM concentrations reduced the abundance of cyanobacteria, nitrospirota, acidobacteriota, and planctomycetota, whereas desulfobacterota, chloroflexi, myxococcota, actinobacteriota, and proteobacteria have developed tolerance to MP-HM. Overall, our findings contribute to the understanding of the relationship between different land-use types and the spatial distribution of MPs and MP-HM, which is critical to manage and mitigate the hyporheic zone pollution.

Dissemination of antibiotic-resistant bacteria associated with microplastics collected from Monastir and Mahdia coasts (Tunisia)

The exponential use of plastics and their recalcitrant nature leads to their significant accumulation in the environment. The occurrence of plastic wastes is considered as a serious environmental problem. Additionally, plastic wastes can break down into smaller pieces called microplastics (MPs), leading to further interactions with the environment and living organisms. In this study, sixty-six strains were isolated from microplastic particles collected on different coastal areas of Monastir and Mahdia (Tunisia). The different bacterial isolates were identified according to some biochemical tests such as catalase, oxidase, and were subjected to molecular characterization. Amplification of the internal transcribed spacer (ITS) revealed the presence of 31 ITS haplotypes. The partial sequencing of the 16S ribosomal DNA of representative strains was analyzed. The majority of bacterial isolates (84.31 %) belonged to Gamma-proteobacteria (84.78 %), while the remaining isolates were affiliated to Firmicutes (15.21 %). The microplastic-associated bacterial isolates belonged to 10 genera, namely Acinetobacter, Pseudomonas, Bacillus, Staphylococcus, Shewanella, Aeromonas, Vibrio, Stutzerimonas, Exiguobacterium, Enterobacter. Among the well-represented Acinetobacter genus, the most common species identified was Acinetobacter johnsonii. Susceptibility patterns of these strains were studied against 21 antibiotics commonly used in Tunisia. A high level of antibiotic resistance was observed for Penicillin G (97.82 %) and Temocillin (86.95 %). S26 strain presented the highest multidrug resistance with a multiple antibiotic resistance (MAR) index of 0.71.

Influence of soil characteristics and agricultural practices on microplastic concentrations in sandy soils and their association with heavy metal contamination

Microplastics (MPs) seriously threaten soil quality and crop health, particularly in agricultural systems using plastic mulch and sewage sludge, with their abundance being strongly influenced by soil properties such as texture, structure, and chemical content. Considering this, the present study assessed MP contamination in arid agricultural soils, focusing on their abundance, morphology, composition, and association with heavy metals to evaluate environmental risks. Soil samples were collected from ten plastic-mulched fields and a control site across a 50 sq. km area. MPs were isolated using density separation and hydrogen peroxide digestion, with morphology categorized through microscopy and polymer composition analysed via FTIR. ICP-OES was used for elemental analysis. Statistical methods, including ANOVA, Pearson's correlation, scatter plots, and PCA, were applied to examine the influence of soil quality on MP levels. Results showed significantly higher MP concentrations in mulched fields (1412 ± 529 particles) compared to the control (72 ± 41 particles), with MPs primarily consisting of fibres, films, fragments, and microbeads. Positive correlations were observed between MPs and soil properties such as clay content, moisture, and organic matter content. FTIR analysis identified eight polymer types, while heavy metals, mainly Fe and Ni, were found to accumulate within MPs. MP counts were positively correlated with mulching duration (r2 = 0.46 to 0.94), indicating increased contamination over time. These findings emphasize the role of soil properties on MP retention and potential risks posed to soil health and environmental sustainability, stressing the need for strategies to mitigate MP contamination in agriculture.

Microplastics originated from Plasmix-based materials caused biochemical and behavioral adverse effects on Daphnia magna

The implementation of advanced recycling techniques represents a key strategy for mitigating the mismanagement and the environmental impact of plastic waste. A limited array of plastic polymers can be efficiently recycled, while a notable portion of plastic waste remains unrecyclable. In Italy, this residual, heterogeneous fraction is referred to as Plasmix. Because of its complexity and non-homogeneous composition, Plasmix is primarily directed towards low-value applications. However, recent developments in laboratory-scale mechanical recycling have enabled the creation of new plastic materials from Plasmix. Prior to their application, these materials must undergo rigorous eco-safety evaluation. The present study aims to assess the potential toxicity of microplastics (MPs) from Plasmix-based materials on the freshwater crustacean Daphnia magna. Specifically, this study investigated sub-individual and individual effects induced by a 21-day exposure to different concentrations of MPs generated from the grinding of naïve and Additivated Plasmix-based materials (hereafter referred to as Px-MPs and APx-MPs, respectively). Sub-individual endpoints focused on changes in oxidative status, including the modulation of antioxidant and detoxifying enzyme activities, as well as oxidative damage, such as lipid peroxidation. Individual level endpoints included alterations in survival and reproduction. Microscopy analyses confirmed the ingestion of both Px-MPs and APx-MPs by D. magna individuals. An oxidative stress condition raised in organisms exposed to Px-MPs, whereas no effect was observed in individuals exposed to APx-MPs. Although survival was not affected, a significant impairment in reproductive output was detected at the end of exposure to all the concentrations of both MP types. These findings suggest that even low concentrations of Px-MPs and APx-MPs could negatively affect the health status of D. magna, underscoring the need for further research to complete the risk assessment of Plasmix-based materials prior to their use in consumer products.

Synergistic effects of microplastics and sulfonamide on greenhouse gas emissions in agricultural ditch sediments: Insights into microbial interactions

Recently, concerns have been raised regarding concurrent pollution by microplastics and antibiotics in agricultural aquatic ecosystems. However, knowledge gaps remain regarding their combined effects on greenhouse gas (GHG) emissions and bacterial community assembly mechanisms. To address this, a microcosm experiment was performed to investigate the GHG (CH4, CO2, and N2O) emission characteristics and bacterial community assembly mechanisms in agricultural ditch sediments under co-exposure to different microplastics (polythene (PE), polylactic acid (PLA)), and sulfanilamide (SA). The global warming potential (GWP) of the different treatments was ranked as follows: SA+PLA (162.96 mg/m2/h) > PLA (123.49 mg/m2/h) > SA (121.75 mg/m2/h) > SA+PE (102.33 mg/m2/h) > CK (without microplastics or antibiotics, 84.67 mg/m2/h) > PE (78.29 mg/m2/h). Additionally, a phylogenetic bin-based null model and molecular ecological network analysis indicated that SA-induced selective pressures reduced compositional turnover, whereas microplastics enhanced drift effects and decreased network robustness. The co-contamination of SA with different microplastics exhibited the opposite effect on the network and assembly process, suggesting that disturbance-mediated species dominance alters the colonization of rare species. Collectively, these findings provide valuable evidence that the synergistic effects of biodegradable microplastic and SA can promote GHG emissions and influence the mechanisms underlying community assembly processes.

Microplastics and orthodontic aligners: The concerns arising from the modernization of practice through polymers and plastics

Plastic aligners have transformed orthodontics, offering a discreet, comfortable, and aesthetically pleasing alternative to traditional fixed appliances. While they have advantages over fixed appliances, they come with environmental and health concerns due to the use of nonbiodegradable plastics, such as the leaching of Bisphenol-A (BPA) and microplastics that can impact human health directly through ingestion. Studies have shown that plastic aligners release microplastics during use, raising concerns about their potential health effects and environmental pollution. The potential health effects of ingested microplastics extend beyond gut microbiota disruption to impact various systems in the body. Research suggests that microplastic exposure can lead to respiratory complications, cardiovascular risks, and implications for brain health and cognitive function. The mechanisms of microplastic uptake into the body through inhalation, ingestion, and skin contact are essential for understanding how these particles interact with human tissues and organs. By prioritizing patient safety, responsible practices, and advancing scientific knowledge the orthodontic community can work towards mitigating the potential health impacts associated with microplastic exposure from aligners.

Response of soil biochemical properties and ecosystem function to microplastics pollution

Microplastics (MPs)-induced changes in soil nutrient cycling and microbial activity may pose a potential risk to soil ecosystem. Although some studies have explored these topics, there is still a large space for exploration and a relative lack of research on the mechanism by which soil health and its functions are affected by these changes. Thus, this study investigated the effects of polyethylene (PE) MPs with two particle sizes (13 μm and 130 μm) at five concentrations (0%, 1%, 3%, 6% and 10%, w/w) on soil biochemical properties and ecosystem function. The findings revealed that the exposure to 13 μm MPs significantly reduced soil respiration (Res) rate, β-glucosidase (Glu) and catalase (CAT) activity, which accompanied with enhanced urease activity and decreased soil pH, available phosphorus (AP), dissolved reactive phosphorus (DRP), dissolved organic carbon (DOC) and available potassium (AK) content in most cases. However, 130 μm MPs exerted negligible influence on the DOC and DRP content, Glu and CAT activity. High concentrations of 130 μm MPs significantly reduced soil pH, total dissolved nitrogen (TDN), AP and AK content, but significantly increased soil Res rate. Overall, soil ecosystem function was significantly reduced by the addition of MPs. The Res rate, soil AP and DRP content and Glu activity were the most important predictors of soil ecosystem function. We found that the risk posed by MPs to soil ecosystem function was dose-dependent and size-dependent. These findings underscore that MPs can alter soil functions related to soil nutrient cycling and provide further insights into MPs behavior in agroecosystems.

Understanding public health risk from unsafe dry fish consumption in Bangladesh

Dried fish holds a significant place in the Bangladeshi diet particularly for people living in coastal regions. However, there is a growing concern regarding its adverse effects on human health, as it contains high levels of illegal preservatives, heavy metals, and other harmful substances. In this study, we aimed to explore the current knowledge, attitudes, and practices regarding health hazards due to unsafe dried fish consumption among people across the country. We conducted a cross-sectional study among consumers to assess their knowledge, attitudes, and practices about the health risks associated with consuming hazardous dried fish. We interviewed a total of 415 participants, of whom 52.8% were male; the majority were students (55.9%), aged between 18 and 30 years (63.9%), and living in urban areas (81.7%). Most of the participants (60.7%) had less accurate knowledge of the health hazards of unsafe dry fish, 92.8% had more positive attitudes to buying safe dry fish, and 26.8% used unsafe dry fish more frequently. Many respondents were unaware of the presence of harmful substances in dried fish, such as illegal pesticides (66.5%), microplastics (77.6%), and heavy metals (67.4%). A significant number of participants (13%) reported that they had a history of cancer in any of their family members. Many individuals (57.4%) were not familiar with the proper storage and preparation methods of dry fish. The majority of participants (81.4%) strongly prefer packed dried fish. Most of the respondents (67.7%) agreed to participate in awareness programs. Female consumers were more likely to have more accurate knowledge (AOR = 1.53; 95% CI = 1.03-2.29, p = 0.0.37) than males, and participants whose present residence were in rural were more likely to have accurate knowledge (AOR = 2.64; 95% CI = 1.30-5.36, p = 0.007) than those whose present residence were in urban or semi-urban areas. A targeted education campaign focused on improving awareness of the risks associated with eating unsafe dry fish is needed, particularly in coastal areas.

Exposure to polystyrene nanoplastics causes immune damage, oxidative stress and intestinal flora disruption in salamander (Andrias davidianus) larvae

The toxic effects of nanoparticles have been increasingly investigated, but there has been limited research on amphibians, especially those of conservation value. This study examined the effects of different concentrations (0, 0.04, 0.2, 1, 5 mg/L) of polystyrene nanoplastics (PS-NPs, 80 nm) on the short-term exposure (7 d) of Andrias davidianus. Results demonstrated the concentration-dependent enrichment of PS-NPs in the intestine. Histological lesions displayed increased hepatic macrophages with cellular rupture, broken intestinal villi, decreased cuprocytes and crypt depression. Antioxidant- and inflammation-related enzyme activities were analysed, and it was found that hepatic and intestinal MDA content and CAT activity were highest in the N-1 group and SOD activity was highest in the N-0.2 group (p < 0.05). AKP activity continued to decline, and iNOS activity was highest in the N-0.2 group (p < 0.05). il-10, tgf-β, bcl-w and txnl1 were significantly downregulated in the N-0.2 group, while il-6 and il-8 were markedly upregulated in the N-0.2 group (p < 0.05). Exposing to PS-NPs decreased probiotic bacteria (Cetobacterium, Akkermansia) and increased pathogenic bacteria (Lachnoclostridium). Our results suggest that NPs exposure can have deleterious effects on salamanders, which predicts that NPs contamination may lead to continued amphibian declines. Therefore, we strongly recommend that attention be paid to amphibians, especially endangered species, in the field of NPs.

Changes in global methylation patterns of Mytilus galloprovincialis exposed to microplastics

Microplastics (MPs) disturb the normal activity of aquatic organisms at different levels, causing physiological stress and altering feeding, growth, and reproduction. Alterations of epigenetic patterns due to exposure to MPs have scarcely been studied in invertebrates. In this study, Mytilus galloprovincialis mussels (N = 61) were intermittently exposed to different concentrations of pure polystyrene microbeads for three weeks. The concentrations used in this research were similar to those currently found in certain polluted environments (E1), as well as higher doses to which mussels could be further exposed (E2 and E3). After exposure period, the global methylation patterns were investigated using Amplified Fragment Length Polymorphism (AFLPs). Significantly lower methylation was found in exposed groups compared to the control group. The level of hypomethylation increased with the concentration of microbeads. Similar results were found from field samples inhabiting two sites differentially MPs-polluted. The implications of this discovery were analysed and discussed, noting the already known effects of MPs on metabolism and cell division. Further studies on this and other sentinel organisms are recommended to understand the response of the aquatic species to the currently increasing MPs pollution.

Microplastics in ecosystems: Critical review of occurrence, distribution, toxicity, fate, transport, and advances in experimental and computational studies in surface and subsurface water

Microplastics (MPs), particles under 5 mm, pervade water, soil, sediment, and air due to increased plastic production and improper disposal, posing global environmental and health risks. Examining their distribution, quantities, fate, and transport is crucial for effective management. Several studies have explored MPs' sources, distribution, transport, and biological impacts, primarily focusing on the marine environment. However, there is a need for a comprehensive review of all environmental systems together for enhanced pollution control. This review critically examines the occurrence, distribution, fate, and transport of MPs in the following environments: freshwater, marine, and terrestrial ecosystems. The concentration of MPs is highly variable in the environment, ranging from negligible to significant amounts (0.003-519.223 items/liter in water and 0-18,000 items/kg dry weight sediment, respectively). Predominantly, these MPs manifest as fibers and fragments, with primary polymer types including polypropylene, polystyrene, polyethylene, and polyethylene terephthalate. A complex interplay of natural and anthropogenic actions, including wastewater treatment plant discharges, precipitation, stormwater runoff, inadequate plastic waste management, and biosolid applications, influences MPs' presence and distribution. Our critical synthesis of existing literature underscores the significance of factors such as wind, water flow rates, settling velocities, wave characteristics, plastic morphology, density, and size in determining MPs' transport dynamics in surface and subsurface waters. Furthermore, this review identifies research gaps, both in experimental and simulation, and outlines pivotal avenues for future exploration in the realm of MPs.

Biotechnology in Food Packaging Using Bacterial Cellulose

Food packaging, which is typically made of paper/cardboard, glass, metal, and plastic, is essential for protecting and preserving food. However, the impact of conventional food packaging and especially the predominant use of plastics, due to their versatility and low cost, bring serious environmental and health problems such as pollution by micro and nanoplastics. In response to these challenges, biotechnology emerges as a new way for improving packaging by providing biopolymers as sustainable alternatives. In this context, bacterial cellulose (BC), a biodegradable and biocompatible material produced by bacteria, stands out for its mechanical resistance, food preservation capacity, and rapid degradation and is a promising solution for replacing plastics. However, despite its advantages, large-scale application still encounters technical and economic challenges. These include high costs compared to when conventional materials are used, difficulties in standardizing membrane production through microbial methods, and challenges in optimizing cultivation and production processes, so further studies are necessary to ensure food safety and industrial viability. Thus, this review provides an overview of the impacts of conventional packaging. It discusses the development of biodegradable packaging, highlighting BC as a promising biopolymer. Additionally, it explores biotechnological techniques for the development of innovative packaging through structural modifications of BC, as well as ways to optimize its production process. The study also emphasizes the importance of these solutions in promoting a circular economy within the food industry and reducing its environmental impact.

Microplastic accumulation in a lizard species: Observations from the terrestrial environments

Microplastics are a global environmental problem, polluting both aquatic and terrestrial environments. Terrestrial lizards are suitable model organisms to study human-induced pollution in these areas, as they can live in urbanized areas where microplastics are most abundant. Therefore, we analyzed the prevalence of microplastics (MPs) in a common Lacertid lizard, the snake-eyed lizard, Ophisops elegans. We detected MPs in the gastrointestinal tract (GIT) of 33 of 152 specimens from 18 populations. The detected MPs had six distinct polymer compositions, namely Polyethylene terephthalate, Polyacrylonitrile, Polypropylene, Polyethylene, Poly methyl methacrylate and Polyamide. The majority of these MPs were fiber-type and the dominant color was navy blue. The lengths of MPs varied from 37 to 563 μm, with an average length of 175 μm. MPs were detected in the GITs of 43% of juveniles (n = 7), 30% of males (n = 105), and 18% of females (n = 40), with a mean of 0.27 per specimen. Furthermore, we found that microplastic densities varied with habitat distance from human settlements, supporting the theory that high levels of microplastic contamination are associated with extensive anthropogenic activity.

Mapping Microplastic Movement: A Phase Diagram to Predict Nonbuoyant Microplastic Modes of Transport at the Particle Scale

Microplastics pose numerous threats to aquatic environments, yet understanding their transport mechanisms remains limited. Drawing from natural sediment research provides valuable insights to address this knowledge gap. One key dimensionless number used to describe sediment transport is the transport stage, referring to the ratio between the flow shear velocity and the particle settling velocity. However, variations in physical properties, such as shape and density, raise concerns about the applicability of existing sediment transport theories to microplastics. To address this challenge, we employed a physical modeling approach, examining 24 different nonbuoyant microplastic particles in a turbulent open channel flow. Utilizing 3D particle tracking, a total of 720 trajectories were recorded and analyzed. Microplastic particles exhibited transport modes akin to natural sediments, including rolling/sliding, saltation, and suspension. The transport stage strongly correlated with these modes, as well as with the mean forward velocity and mean position in the water column. Notably, particle shape emerged as a critical factor influencing transport dynamics. Due to their lower settling velocity, fibers tended to stay closer to the water surface with lower forward velocities compared to spheres. Based on the laboratory results, a new phase diagram for microplastics is introduced analogous to an existing diagram for sediments.

Using machine learning to reveal drivers of soil microplastics and assess their stock: A national-scale study

The issue of microplastic (MP) contamination in soil is a significant concern. However, due to limited large-scale studies and stock assessments, our understanding of the drivers of their distribution and fate remains incomplete. To address this, we conducted a comprehensive study in China, collected MP data from 621 sites, and utilized machine learning techniques for analysis. Our findings revealed 9 key factors influencing the distribution of soil MPs, highlighting their nonlinear influence processes. Among these factors, atmospheric deposition emerged as the most dominant driver, while wind and precipitation could lead to the transformation of soil from a sink to a source of MPs. MP concentrations in Chinese soils vary from 1.4 to 4333.1 particles/kg, with human activities significantly affecting their distribution, resulting in higher concentrations in the east and lower concentrations in the west. The estimated MP stock in Chinese soils is 1.92 × 1018 particles, equivalent to a mass of 2.11-8.64 million tonnes. This stock alone surpasses that found in global oceans, making global soil the largest reservoir of MPs. Overall, this study enhances our understanding of the environmental behavior of MPs and provides valuable data and theoretical support for the prevention, control, and management of this contamination.

Microplastics in the atmospheric of the eastern coast of China: different function areas reflecting various sources and transport

Suspended atmospheric microplastics (SAMPs) display varying occurrence characteristics on different underlying surfaces in urban areas. This study investigated the occurrence characteristics, source apportionment, and transportation patterns of SAMPs in two typical underlying surfaces: the downtown area (Site T) and the industrial area (Site C) of a coastal city in China. In the spring of 2023, a total of 32 types comprising 1325 SAMPs were detected. The average MP abundances were found to be 3.74 ± 2.86 n/m3 in Site T and 2.67 ± 1.68 n/m3 in Site C. In Site T, SAMPs attributed to living source constituted 78.05%, while industry was the main source in Site C with a proportion reaching 42.89%, consistent with the functional zoning of the underlying surface. Furthermore, HYSPLIT analysis revealed that there was no significant difference between these two sites in long-distance horizontal transport affected by external airflow regardless of altitude; conversely, PCA indicated a notable correlation between vertical velocity and both abundance and species diversity. According to the hourly average wind speeds, the maximum transmission distance was computed as 350 km for updraft and the minimum transmission distances was as low as 32 m for downdraft. Subsequently, the coincidence between the source proportion of SAMPs on random day and meteorological parameters confirmed the synergistic impact on SAMPs transport influenced by functional zoning, geographic environment, and vertical velocity.

Alleviating effects of microplastics together with tetracycline hydrochloride on the physiological stress of Closterium sp

Microplastics have significant influence on both freshwater cyanobacteria and marine microalgae, especially under co-exposure with other pollutants such as heavy metals, antibiotics, and pharmaceuticals. In the present study, combined effects of microplastics (polyethylene terephthalate (PET) or polybutylene terephthalate (PBT)) and tetracycline hydrochloride (TCH) on the microalgae Closterium sp. were studied to evaluate their acute toxicity, and the cell density, total chlorophyll concentration, photosynthetic activity, antioxidant system, and subcellular structure of Closterium sp. under different treatments were used to explain the physiological stress mechanism of the combined effects. The results indicate that both the single and combined treatments have inhibition effects on the cell growth and photosynthetic activity, with inhibition efficiencies (in terms of cell density) of 5.0%, 9.2%, 66.7%, 55.1%, and 59.8% for PET (100 mg L-1), PBT (100 mg L-1), TCH (10 mg L-1), PET/TCH (PET 100 mg L-1 and TCH 10 mg L-1), and PBT/TCH (PBT 100 mg L-1 and TCH 10 mg L-1), respectively, and relative electron-transport rates (rETRs) of 7.3%, 12.7%, 66.8%, 54.0%, and 59.9%, respectively, for each treatment compared with the control on the 7th day. Moreover, both PET and PBT have positive effects in alleviating TCH toxicity toward Closterium sp., and at the same time, the malondialdehyde level (MDA), superoxide dismutase (SOD) activity, and catalase (CAT) activity induced by the combined treatments were much higher than those from the single microplastic treatments but lower than those from TCH treatment after 7 days. It was demonstrated that TCH causes a much more serious oxidative stress than PET/TCH and PBT/TCH, and the lower oxidative stress of the PET/TCH and PBT/TCH groups could be attributed to the adsorption of TCH to PET or PBT. This work improves the understanding of the combined toxicity effects of microplastics and TCH on Closterium sp.

Mitigating the detrimental impacts of low- and high-density polyethylene microplastics using a novel microbial consortium on a soil-plant system: Insights and interactions

The accumulation of polyethylene microplastics (PE-MPs) in soil has raised considerable concerns; however, the effects of their persistence and mitigation on agroecosystems have not been explored. This study aimed to assess the detrimental effects of PE-MPs on a soil-plant system and evaluate their mitigation using a novel microbial consortium (MC). We incorporated low-density polyethylene (LDPE) and high-density polyethylene (HDPE) at two different concentrations, along with a control (0 %, 1 %, and 2 % w/w) into the sandy loam soil for a duration of 135 days. The samples were also treated with a novel MC and incubated for 135 days. The MC comprised three bacterial strains (Ralstonia pickettii (MW290933) strain SHAn2, Pseudomonas putida strain ShA, and Lysinibacillus xylanilyticus XDB9 (T) strain S7-10F), and a fungal strain (Aspergillus niger strain F1-16S). Sunflowers were subsequently cultivated, and physiological growth parameters were measured. The results showed that adding 2 % LDPE significantly decreased soil pH by 1.06 units compared to the control. Moreover, adding 2 % HDPE resulted in a more significant decrease in soil electrical conductivity (EC) relative to LDPE and the control. A dose-dependent increase in dissolved organic carbon (DOC) was observed, with the highest DOC found in 2 % LDPE. The addition of higher dosages of LDPE reduced soil bulk density (BD) more than HDPE. The addition of 2 % HDPE increased the water drop penetration time (WDPT) but decreased the mean weight diameter of soil aggregates (MWD) and water-stable aggregates (WSA) compared to LDPE. The results also revealed that higher levels of LDPE enhanced soil basal respiration (BR) and microbial carbon biomass (MBC). The interaction of MC and higher MP percentages considerably reduced soil pH, EC, BD, and WDPT but significantly increased soil DOC, MWD, WSA, BR, and MBC. Regarding plant growth, incorporating 2 % PE-MPs significantly reduced physiological responses of sunflower: chlorophyll content (Chl; -15.2 %), Fv/Fm ratio (-25.3 %), shoot dry weight (ShD; -31.3 %), root dry weight (RD; -40 %), leaf area (LA; -38.4 %), and stem diameter (StemD; -25 %) compared to the control; however, the addition of novel MC considerably reduced and ameliorated the harmful effects of 2 % PE-MPs on the investigated plant growth responses.

Water-dependent effects of biodegradable microplastics on arsenic fractionation in soil: Insights from enzyme degradation and synchrotron-based X-ray analysis

The abundance of biodegradable microplastics (BMPs) is increasing in soil due to the widespread use of biodegradable plastics. However, the influence of BMPs on soil metal biogeochemistry, especially arsenic (As), under different water regimes is still unclear. In this study, we investigated the effects of two types of BMPs (PLA-MPs and PBAT-MPs) on As fractionation in two types of soils (black soil and fluvo-aquic soil) under three water regimes including drying (Dry), flooding (FL), and alternate wetting and drying (AWD). The results show that BMPs had limited indirect effects on As fractionation by altering soil properties, but had direct effects by adsorbing and releasing As during their degradation. Enzyme degradation experiments show that the degradation of PLA-MPs led to an increased desorption of 4.76 % for As(III) and 15.74 % for As(V). Synchrotron-based X-ray fluorescence (μ-XRF) combined with micro-X-ray absorption near edge structure (μ-XANES) analysis show that under Dry and AWD conditions, As on the BMPs primarily bind with Fe hydrated oxides in the form of As(V). Conversely, 71.57 % of As on PBAT-MP under FL conditions is in the form of As(III) and is primarily directly adsorbed onto its surface. This study highlights the role of BMPs in soil metal biogeochemistry.

PM10-bound microplastics and trace metals: A public health insight from the Korean subway and indoor environments

Inhalable airborne microplastics (MPs) presented in indoor and outdoor environments, can deeply penetrate the lungs, potentially triggering inflammation and respiratory illnesses. The present study aims to evaluate human health risks from respirable particulate matter (PM)-bound trace metals and MPs in indoor (SW- subway and IRH- indoor residential houses) and outdoor (OD) environments. This research provides an initial approach to human respiratory tract (HRT) mass depositions of PM10-bound total MPs and nine specific MP types to predict potential human health threats from inhalation exposure. Results indicate that PM-bound trace metals and MPs were around 4 times higher in SW microenvironments compared to OD locations. In IRH, cancer risk (CR) levels were estimated 9 and 4 times higher for PM10 and PM2.5, respectively. Additionally, MP particle depositions per gram of lung cell weight were highest in IRH (23.77), followed by OD and SW. Whereas, lifetime alveoli depositions of MPs were estimated at 13.73 MP/g, which exceeds previously reported respiratory disease fatality cases by 10 to 5 times. Prolonged exposure duration at IRH emerged as a key factor contributing to increased CR and MP lung deposition levels. This research highlights severe lung risks from inhaling PM-bound MPs and metals, offering valuable health insights.

Effects of biodegradable microplastics coexistence with biochars produced at low and high temperatures on bacterial community structure and phenanthrene degradation in soil

The increasing use of biodegradable plastics may result in more serious pollution of microplastics which often coexist with biochar in soil, this will affect how organic pollutants move and transform in the soil. This work investigated the effect of biodegradable polybutylene adipate-co-terephthalate (PBAT) coexistence with biochars produced at temperatures of 400 and 700 °C (W4 and W7) on soil bacterial communities and phenanthrene degradation. The results showed that coexistence of PBAT and biochar paticles greatly boosted the relative abundance of Nocardioides while decreased the relative abundance of Sphingomonas as compared to soils with a single addition of PBAT or biochar. Changes in soil Eh values were the most influential factor in bacterial communities (more than 40% contribution). The degradation ratio of phenanthrene when PBAT coexisted with W7 (39.6 ± 3.6%) was not significantly different from the treatment with a single W7 addition (35.0 ± 2.3%, P＞0.05), and was related to phenanthrene degradation in the adsorbed state of W7 in soil. In contrast, the degradation ratio of phenanthrene in PBAT coexisting with W4 (35.1 ± 3.5%) was intermediate between that of single PBAT (49.8 ± 0.9%) and W4 (13.7 ± 5.8%) treatments. This was primarily due to changes in the experiment's initial bioavailable phenanthrene content. Furthermore, after the introduction of earthworms, phenanthrene degradation ratio in coexistence treatments were very similar to that described above in the absence of earthworms. Except for two treatments that contain W7, phenanthrene degradation ratio in the other treatments was increased by the presence of earthworms (up to 23%), which is related to the enhanced relative abundance of polycyclic aromatic hydrocarbon-degraders. Our findings indicated that PBAT coexistence with high-temperature or low-temperature biochar had a completely different impact on bacterial communities and phenanthrene degradation in soil.

Microplastic contamination of bryophytes: A review on mechanisms and impacts

This systematic review investigates the interactions of microplastics (MPs) and nanoplastics (NPs) with bryophytes, incorporating findings from 11 articles identified through a comprehensive database search using a combination of keywords. The review explores mechanisms such as adsorption and internalization by which MPs and NPs are present in bryophytes and examines the ecological ramifications, including changes in bryophyte community structure and impacts on ecosystem functions such as nutrient cycling, soil formation, habitat provision, water balance, and erosion control. Despite providing valuable insights, this review highlights several critical knowledge gaps that warrant further investigation. Future research should address the following areas: the long-term effects of MPs and NPs on bryophyte health and survival, the mechanisms of MP and NP uptake and translocation within bryophytes, and the broader ecological consequences of plastic pollution on bryophyte-dominated ecosystems. Additionally, studies should explore the effectiveness of various mitigation and management strategies, including advanced waste management techniques and innovative technologies, in reducing plastic pollution and protecting these vital ecosystems.

Impacts of Environmental Concentrations of Nanoplastics on Zebrafish Neurobehavior and Reproductive Toxicity

Nanoplastics, as emerging environmental pollutants, can transport contaminants across marine environments, polluting pristine ecosystems and being ingested by marine organisms. This transfer poses a severe threat to global aquatic ecosystems and potentially impacts human health through the food chain. Neurobehavioral and reproductive toxicity are critical areas of concern because they directly affect the survival, health, and population dynamics of aquatic species, which can have cascading effects on the entire ecosystem. Using zebrafish as a model organism, we investigated the toxic effects of environmental concentrations of polystyrene nanoplastics (PS-NPs). Behavioral assessments, including the novel tank test and open field test, demonstrated significant neurobehavioral changes, indicating increased anxiety and depressive behaviors. A pathological analysis of brain and gonadal tissues, along with evaluations of neurobehavioral and reproductive toxicity biomarkers, revealed that exposure to PS-NPs leads to brain tissue lesions, inflammatory responses, oxidative stress activation, hormone level disruptions, and gonadal damage. Real-time quantitative PCR studies of reproductive gene expression further showed that PS-NPs disrupt the endocrine regulation pathways of the brain-pituitary-gonadal (BPG) axis, causing reproductive toxicity with sex-specific differences. These findings provide crucial insights into the impacts of nanoplastics on aquatic organisms and their ecological risks, offering theoretical support for future environmental protection and pollutant management efforts.

Effect of microplastics used in agronomic practices on agricultural soil properties and plant functions: Potential contribution to the circular economy of rural areas

The extensive use of plastic materials and their improper disposal results in high amounts of plastic waste in the environment. Aging of plastics leads to their breakdown into smaller particles, such as microplastics (MPs) and nanoplastics. This research investigates plastics used in agricultural practices as they contribute to MP pollution in agricultural soils. The distribution and characteristics of MPs in agricultural soils were evaluated. In addition, the effect of MPs on soil properties, the relationship between MPs and metals in soil, the effect of MPs on the fate of pesticides in agricultural soils and the influence of MPs on plant growth were analysed, discussing legume, cereal and vegetable crops. Finally, a brief description of the main methods of chemical analysis and identification of MPs is presented. This study will contribute to a better understanding of MPs in agricultural soils and their effect on the soil-plant system. The changes induced by MPs in soil parameters can lead to potential benefits as it is possible to increase the availability of micronutrients and reduce plant uptake of toxic elements. Furthermore, although plastic pollution remains an emerging threat to soil ecosystems, their presence may result in benefits to agricultural soils, highlighting the principles of the circular economy.

The dynamic relationship between skin microbiomes and personal care products: A comprehensive review

Healthy skin reflects a healthy microbiome and vice versa. The contemporary society, marked by a sharp increase in skin irritation cases, has compelled researchers, dermatologists, and the cosmetics industry to investigate the correlation between skin microbiomes and the use of skincare products. Different cosmetics can change skin's normal flora to a varying degree -some changes can be detrimental, there are also instances where these alterations aid in restoring the skin microbiome. Previous studies using artificial skin models, metagenomic analysis, and culture-based approaches have suggested that skincare products play an important role in skin microbial alteration. This article assessed current knowledge on microbial shifts from daily use of various personal and skincare products. We have also introduced a readily applicable framework, synthesized from various observations, which can be employed to identify the normal skin microbiome and evaluate the impact of personal care and skincare products on it. We also discussed how lifestyle choice remake skin microbial makeup. Future studies are warranted to examine the effect of personal and skincare product usage on skin microbiome across various age groups, genders, and body sites with a multi-study approach.

The competition of heavy metals between hyporheic sediments and microplastics of driving factors in the Beiluo River Basin

Both sediments and microplastics (MPs) are medias of heavy metals (HMs) in river ecosystems. This study investigated HMs (Mn, Cr, V, As, Cu, Co, Cd, Pb, and Ni) concentration and driving factors for competitive enrichment between hyporheic sediments versus MPs. The medias basic characteristics indicated that the sediments were mostly sand and rich in Fe2O3; three polymer types were identified, with blue, fragment, less than 500 µm being the main types of MPs. The results have shown that the average content of extracted HMs in MPs was much higher than that of the same metals accumulated in sediments. HMs in sediments and MPs reached heavily polluted at some points, among which As and Cd were ecological risks. Electrostatic adsorption and surface complexation, and biofilm-mediated and organic matter complexation were the interaction mechanism of HMs with sediments and MPs. Further, the driving factors affecting the distribution of HMs in the two carriers were analyzed by multivariate statistical analysis. The results demonstrated that carrier characteristics, hydrochemical factors, and the inherent metal load of MPs were the main causes of the high HMs content. These findings improved our understanding of HMs fate and environmental risks across multiple medias.

Airborne transboundary microplastics-A Swirl around the globe

Microplastics are persistent pollutants discovered and extensively researched in marine, freshwater, and terrestrial ecosystems but have yet to receive attention in an atmospheric context. Although recent reports stated the presence of microplastics in the air, their global existence and distribution are not critically discussed to date. This review aimed to investigate the current status of research on atmospheric microplastics through bibliometric analysis and by comparing and summarising published research on global distribution. The review also provides a summary of methods that have been used to collect samples, identify microplastics, quantify their occurrence, and determine their transport mechanisms. The bibliometric analysis revealed that atmospheric microplastic studies predominantly originated in China. Clothing, vehicle, and tire materials were the major primary sources while house furniture, construction materials, landfills, urban dust, plastic recycling processes, and agricultural sludge were precursor secondary sources. Polyethylene, polypropylene, and polyethylene terephthalate microfibres have most frequently found in indoor and outdoor atmospheres. Level of urbanization and temporal or spatial distributions governs the fate of airborne microplastics, however, the knowledge gap in the retention and circulation of microplastics through the atmosphere is still large. Many challenges and limitations were identified in the methods used, presentation of data, aerodynamic processes facilitating atmospheric transport, and scarcity of research in spatially and temporally diverse contexts. The review concluded that there was a greater need for globalization of research, methods and data standardization, and emphasizes the potential for future research with atmospheric transportation modelling and thermochemical analysis.