Different Types Of Microplastics Research Articles

Comprehensive analysis reveals the differentiated influential mechanism of biodegradable and non-biodegradable microplastics on core microbial metabolisms and functional genes in an adsorption-biological coupling wastewater treatment system

The effects of different types of microplastics (MPs) on the wastewater treatment efficiency of an adsorption-biological coupling system were investigated. The distribution of the microbial community and metabolic pathways in the coupled system were also analyzed. Biodegradable polybutylene succinate microplastics (PBS MPs) were added to reactor A, while non-biodegradable polystyrene microplastics (PS MPs) was added to reactor B. The average chemical oxygen demand (COD) removal rates in reactor A with 0, 50, and 100 mg/L of MPs were 95.34 %, 89.13 %, and 86.08 %, respectively; the average COD removal rates in reactor B were 96.84 %, 88.43 %, and 87.02 %, respectively. The average total phosphorus (TP) removal rates in reactor A were 74.14 %, 38.94 %, and 36.45 %, respectively, while those in reactor B were 71.73 %, 39.50 %, and 33.09 %, respectively. In the two reactors, Proteobacteria had the highest relative abundance (53 %–62 %), followed by Actinobacteria. PS MPs inhibited the expression of quorum sensing genes by influencing SecA and SecY. Horizontal transfer genes illustrated that both MPs led to up-regulation of reactive oxygen species (ROS)-related functional genes. During glycolysis, the abundances of glucokinase (GLK), pyruvate kinase (PK), and phosphofructokinase (PFK) in reactor A were 0.0179 %, 0.0133 %, and 0.0387 % higher than that in reactor B, respectively. Meanwhile, in nitrogen metabolism, the abundance of key genes such as nasA (A: 40.8 % B: 37.9 %) was greater in reactor A than in reactor B.

Nascently generated microplastics in freshwater stream are colonized by bacterial communities from stream and riparian sources.

The purpose of this study was to examine bacterial colonization of different types of microplastics through time in a freshwater ecosystem. Microplastics are persistent pollutants in aquatic ecosystems. Bacteria readily colonize microplastic surfaces and may contribute to their degradation, but the taxa involved, and their degradative abilities, differ based on factors such as microplastic chemistry, plastic age, and specific ecosystem types. Four different common types of newly manufactured microplastics, high-density polyethylene, low-density polyethylene, polypropylene, and polystyrene, were incubated for 7 weeks in a freshwater stream and sampled. Sample collection was timed to examine the development of early and late bacterial biofilm communities. Microplastics were analyzed for changes to buoyancy, weight, contact angles (an indicator of surface roughness), bacterial community composition, and the number of bacterial cells. Time was the only significant contributing factor in the development of bacterial biofilm communities on microplastic disks over the 7-week study. Notably, the Comamonadaceae were abundant early in the study and decreased in abundance with time, while the Methylococcaceae demonstrated the opposite trend. Different physicochemical properties among the various types of microplastics had only a minor effect on bacterial community compositions of biofilms growing on the microplastics. Additionally, the surfaces of all microplastic disks became rougher over time in the stream. Collectively, our results show that microplastic surfaces undergo surface modification and community succession as time progresses, regardless of microplastic type, in a freshwater stream ecosystem.

Effect of different microplastics on the mobilization of soil inorganic phosphorus by exomycorrhizal fungi

<p>Microplastics (MPs) can affect the phosphorus (P) cycle in soil by changing soil properties and the function of microbial communities, but their impact on soil P availability remains unclear. To explore the effects of different types of MPs on the mobilization of soil inorganic P by exomycorrhizal fungi, Lactarius delicious (Ld) was used as the test strain, and polystyrene microspheres (PS), polypropylene (PP) and poly(lactic acid) (PLA) were used as test materials. The soil was used as the only P source for the media. The effect of different types of MPs on the mobilization of soil inorganic P by exomycorrhizal fungi was studied using liquid culture method. The results showed that exposure to MPs at low to medium concentrations (10 or 100 mg L-1) activated inorganic P in soil by stimulating the secretion of additional organic acids and hydrogen ions by ectomycorrhizal fungi, improving the available P in soil. The effect of mobilizing inorganic P was more significant in the treatment groups exposed to low and medium concentrations of biodegradable PLA. This may be related to the fact that PLA stimulated the ectomycorrhizal fungi to secrete more organic acids, and the release of a large amount of lactic acid after PLA was biodegraded. However, when the exposure concentration of MPs further increased, the growth of ectomycorrhizal fungal mycelium may be inhibited, the secretion of organic acids and hydrogen ions may be reduced, and the mobilization ability of soil inorganic P may be limited. In addition, it should be noted that high concentrations of non biodegradable MPs (PS and PP) had significant limiting effects on the mobilization of soil inorganic P by exomycorrhizal fungi. Therefore, our study results provide evidence that the presence of MPs may reduce the availability of soil P. Further research should focus on maintaining or improving P availability in plant-microbe systems in MP-polluted soil.</p>

Elucidating the role of rice straw biochar in modulating Helianthus annuus L. antioxidants, secondary metabolites and soil post-harvest characteristics in different types of microplastics

The emergence of microplastics (MPs) as pollutants in agricultural soils is increasingly alarming, presenting significant threats to soil ecosystems. Given the widespread contamination of ecosystems by various types of MPs, including polystyrene (PS), polyvinyl chloride (PVC), and polyethylene (PE), it is crucial to understand their effects on agricultural productivity. The present study was conducted to investigate the effects of different types of MPs (PS, PVC, and PE) on various aspects of sunflower (Helianthus annuus L.) growth with the addition of rice straw biochar (RSB). This study aimed to examine plant growth and biomass, photosynthetic pigments and gas exchange characteristics, oxidative stress indicators, and the response of various antioxidants (enzymatic and non-enzymatic) and their specific gene expression, proline metabolism, the AsA–GSH cycle, cellular fractionation in the plants and post-harvest soil properties. The research outcomes indicated that elevated levels of different types of MPs in the soil notably reduced plant growth and biomass, photosynthetic pigments, and gas exchange attributes. Different types of MPs also induced oxidative stress, which caused an increase in various enzymatic and non-enzymatic antioxidant compounds, gene expression and sugar content; notably, a significant increase in proline metabolism, AsA–GSH cycle, and pigmentation of cellular components was also observed. Favorably, the addition of RSB significantly increased plant growth and biomass, gas exchange characteristics, enzymatic and non-enzymatic compounds, and relevant gene expression while decreasing oxidative stress. In addition, RSB amendment decreased proline metabolism and AsA-GSH cycle in H. annuus plants, thereby enhancing cellular fractionation and improving post-harvest soil properties. These results open new avenues for sustainable agriculture practices and show great potential for resolving the urgent issues caused by microplastic contamination in agricultural soils.

The comparative toxicity of biobased, modified biobased, biodegradable, and petrochemical-based microplastics on the brackish water flea Diaphanosoma celebensis

The escalating production and improper disposal of petrochemical-based plastics have led to a global pollution issue with microplastics (MPs), which pose a significant ecological threat. Biobased and biodegradable plastics are believed to mitigate plastic pollution. However, their environmental fate and toxicity remain poorly understood. This study compares the in vivo effects of different types of MPs, poly(butylene adipate-co-terephthalate) as a biodegradable plastic, polylactic acid (PLA) as a biobased plastic, β-cyclodextrin-grafted PLA as a modified biobased plastic, and low density polyethylene as the reference petrochemical-based plastic, on the key aquatic primary consumer Diaphanosoma celebensis. Exposure to MPs resulted in significant reproductive decline, with comparable effects observed irrespective of MP type or concentration. Exposure to MPs induced distinct responses in redox stress, with transcriptional profiling revealing differential gene expression patterns that indicate varied cellular responses to different types of MPs. ATP-binding cassette transporter activity assays demonstrated altered efflux activity, mainly in response to modified biobased and biodegradable MPs. Overall, this study highlights the comparable in vivo and in vitro effects of biobased, biodegradable, and petrochemical-based MPs on aquatic primary consumers, highlighting their potential ecological implications.

Effects of food quantity on the ingestion and egestion of MPs with different colors by Daphnia magna

Aquatic organism uptake and accumulate microplastics (MPs) through various pathways, with ingestion alongside food being one of the primary routes. However, the impact of food concentration on the accumulation of different types of MPs, particularly across various colors, remains largely unexplored. To address this gap, we selected Daphnia magna as a model organism to study the ingestion/egestion kinetics and the preference for different MP colors under varying concentrations of Chlorella vulgaris. Our findings revealed that as the concentration of Chlorella increased, the ingestion of MPs by D. magna initially increased and then showed a decline. During the egestion phase within clean medium without further food supply, an increase in food concentration during the ingestion phase led to a slower rate of MP discharge; while when food was present during the egestion phase, the discharge rate accelerated for all treatments, indicating the importance of food ingestion/digestion process on the MPs bioaccumulation. Furthermore, in the presence of phytoplankton, D. magna demonstrated a preference for ingesting green-colored MPs, especially at low and medium level Chlorella supply, possibly due to the enhanced food searching activities. Beyond gut passage, we also examined the attachment of MPs to the organism's body surface, finding that the number of adhered MPs increased with increasing food concentration, likely due to the intensified filtering current during food ingestion. In summary, this study demonstrated that under aquatic environment with increasing phytoplankton concentrations, the ingestion and egestion rates, color preferences, as well as surface adherence of MPs to filter feeding zooplanktons will be significantly influenced, which may further pose ecological risks. Our results offer novel insights into the unintentional accumulation of MPs by zooplankton, highlighting the complex interactions between food availability and MPs accumulation dynamics.

Microplastics in gully pot sediment in urban areas: Presence, quantities and characteristics

Stormwater is widely recognized as a pathway for transporting pollutants, including microplastics, from sources in urban environments to receiving waters. Gully pots are often where urban runoff drains into the piped network; they typically include a trap where sediments accumulate. The aim of this work was to contribute to a better understanding of the fate of microplastics as they enter into the urban drainage system, and the role of gully pots in trapping microplastics. Sediment samples collected from 29 gully pots were analysed for non-carbon-black and carbon-black (e.g. tire wear particles) microplastics larger than 40 μm using μ-FTIR and ATR-FTIR, respectively. Commonly found polymers in descending order were PP > EPDM > EVA > PS > SBR, PP was most common both by mass and by number of microplastics. The total concentration of carbon black and non-carbon black microplastics ranged from 709 to 10 600 items/100 g dry matter (DM), (median: 2960 items/100 g). Estimated mass of non-carbon black microplastics ranged from 0.19 to 490 mg/100 g, (median: 3.66 mg/100 g). In total 21 different types of microplastics were detected, the majority of these (13) were carbon black and eight non-carbon black polymer types. By number and the carbon black particles accounted for up to 68% of the microplastics (average 30%), this stress the importance of using analytical methods enabling the detection of both carbon-black and non-carbon black microplastics. Furthermore, the results indicate that gully pots can act as temporary sinks for microplastics, mainly for microplastics larger than 125 μm. The amount of microplastics found in gully pots, together with the very large number of gully pots sited in urban areas, indicates that gully pots can potentially trap large amounts of microplastics, and thus if gully pots are fitted and maintained properly they could significantly contribute to reducing the amount of microplastics reaching receiving waters.

Message in a (Plastic) Bottle

Microplastics are plastic pieces less than 5 mm in diameter and are a widespread contaminant in waterways worldwide. Microplastics can be split into four categories: beads, fragments, thin films, or fibers. In this activity, students learn about microplastics in the environment and as hazards to marine life. Students create a “MicroGlobe” that mimics real-world microplastic contamination in marine environments. Students calculate the percentages of different types of microplastics and generate pie charts of the collected data. They are challenged to think about ways they can be better stewards of the Earth and their answers in the math exercise are used to answer questions about how their “MicroGlobes” differ from real-world data in the provided Activity Packet. This activity has modifications for students with visual impairments.

Exploring Bacillus mycoides PM35 efficacy in enhancing rice (Oryza sativa L.) response to different types of microplastics through gene regulation and cellular fractionation.

Soil contamination with microplastics (MPs) is a persistent threat to crop production worldwide. With a wide range of MP types, including polystyrene (PS), polyvinyl chloride (PVC) and polyethylene (PE), contaminating our environment, it is important to understand their impact on agricultural productivity. The present study was conducted to investigate the effects of different types of MPs (PS, PVC and PE) on various aspects of plant growth. Specifically, we examined growth and biomass, photosynthetic pigments, gas exchange attributes, oxidative stress responses, antioxidant compound activity (both enzymatic and non-enzymatic), gene expression, proline metabolism, the AsA-GSH cycle and cellular fractionation and nutritional status, in different parts of rice (Oryza sativa L.) seedlings, which were also exposed to plant growth promoting rhizobacteria (PGPR), i.e. Bacillus mycoides PM35, i.e. 20 μL. The research outcomes indicated that the different types of MPs in the soil notably reduced plant growth and biomass, photosynthetic pigments and gas exchange attributes. However, MP stress also induced oxidative stress in the roots and shoots of the plants by increasing malondialdehyde (MDA), hydrogen peroxide (H2O2) and electrolyte leakage (EL) which also induced increased compounds of various enzymatic and non-enzymatic antioxidants and also the gene expression. Furthermore, a significant increase in proline metabolism, the AsA-GSH cycle, and the fractionations of cellular components was observed. Although the application of B. mycoides PM35 showed a significant increase in plant growth and biomass, gas exchange characteristics, enzymatic and non-enzymatic compounds and their gene expression and also decreased oxidative stress. In addition, the application of B. mycoides PM35 enhanced cellular fractionation and decreased the proline metabolism and AsA-GSH cycle in O. sativa plants. These results open new insights for sustainable agriculture practices and hold immense promise in addressing the pressing challenges of MP contamination in agricultural soils.

Selective visual staining of polyurethane microplastics by novel colorimetric and near-infrared (NIR) fluorescent dye: Application to environmental water and natural soil samples

Microplastics can cause environmental pollution and ecosystem destruction as well as human health problems. Among the types of microplastics, polyurethane (PU) is particularly resistant to heat and difficult to decompose, causing disposal problems, and is evaluated as one of the most hazardous polymers. We present a novel colorimetric and near-infrared (NIR) fluorescence dye, (E)-N-(2-((4-(diphenylamino)benzylidene)amino)phenyl)− 7-nitrobenzo[c][1,2,5]oxadiazol-4-amine (DPNA), designed for selective visual PU microplastic staining. The intramolecular charge transfer (ICT) properties of DPNA are demonstrated through density functional theory (DFT) calculations along with solvatochromic shift. DPNA exhibits red color and red fluorescence emission, showing promising potential as a staining dye. To achieve selective PU microplastic staining, we establish an optimized experimental procedure with the staining dye DPNA by evaluating the staining efficiency under different staining solvent compositions and staining times. DPNA can distinguish PU by both red fluorescence signal and red coloration among different types of microplastics. In addition, DPNA well stain fresh PUs with diverse sizes and at various pH range of 5–9, and the aged PUs can also be dyed as effectively as the fresh PU. Most importantly, DPNA selectively stains PU among 11 types of microplastics and 5 types of natural particles in environmental water and soil with and without any pre-treatments. The adsorption mechanism of DPNA on PU microplastic is demonstrated through field emission scanning electron microscopes (FE-SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and non-covalent interaction (NCI)-reduced density gradient (RDG) analyses, and proposed that intermolecular hydrogen bonding has a significant effect.

Microplastic contaminants detection in aquatic environment by hydrophobic cerium oxide nanoparticles

Microplastics (MPs) poses a significant threat to ecosystems and human health, demanding immediate attention. The reported research work offers an effective and low cost method towards the detection of toxic MPs. In this study, hydrophobic cerium oxide nanoparticles (CeO2 NPs) are synthesized and applied as promising electrode material for the detection of two different types of MPs, i.e. polyethylene (PE) and polypropylene (PP). Through electrochemical analyses, such as cyclic voltammetry (CV) and linear sweep voltammetry (LSV), hydrophobic CeO2 NPs modified glassy carbon electrode (GCE) based sensor demonstrated remarkable sensitivity of ∼0.0343 AmLmg−1cm−2 and detection limit of ∼0.226 mgmL−1, with promising correlation coefficient (R2) towards the detection of PE (∼27–32 μm). Furthermore, hydrophobic CeO2 NPs modified GCE exhibited promising stability and reproducibility towards PE (∼27–32 μm), suggesting the promising potential of hydrophobic CeO2 NPs as electrode materials for an electrochemical microplastics detection.

Efficiency and costs of household filters for the retention of fibrous microplastics from the laundry process in Germany

Synthetic fiber fragments from household washing are one of many types of microplastics that enter the environment. The potential and costs of fiber retention, using filters, were modeled for Germany. The high costs indicate that synergistic measures for the simultaneous retention of different types of microplastics from other sectors, such as road traffic, should not be overlooked in terms of cost-effectiveness. Around 500 tons of microplastics enter the wastewater from washing machines every year, of which, around 91 % is removed by conventional wastewater treatment. The separation costs amount to approximately EUR 2.2 million per ton. The widespread use of filters already available on the market in households could increase the proportion removed to 96 %. The costs for the additional separation amount to approximately 114 million EUR per ton. The use of filters would increase the costs for household washing by approximately 37 %.A comparison with the separation of tire wear reveals synergy potential. Around 20,000 tonnes of microplastics from tire wear are subjected to conventional wastewater treatment in the same way as the fibrous microplastics from the washing process. One starting point, for example, is that both types of microplastics can bypass the wastewater treatment plants and enter the environment as so-called overflow if the wastewater network is overloaded. The potential to reduce the input of microplastics, by reducing the release through overflows, far exceeds the savings potential of individual measures such as the installation of filters in households.

Identification of Microplastics Using µ-Raman Spectroscopy in Surface and Groundwater Bodies of SE Attica, Greece

Sixteen surface (5) and groundwater (11) samples were collected from the south-eastern part of Attica, Greece, and analysed for physico-chemical parameters and microplastics (MPs) by optical microscopy and Raman microspectroscopy (RS). A total of 3399 particles were optically identified in all sixteen samples, ranging from only 16 particles/L in a sample from a deeper borehole to 513 particles/L in a sample from a shallow water well. They were then visually classified into eight categories based on their color, texture, size, reflectivity, shape, and general morphological properties. Raman microspectroscopy was performed on the particles on the filters and revealed four different types of MPs, namely polyethylene (PE, 35%), polypropylene (PP, 30%), polystyrene (PS, 10%), and polyethylene terephthalate (PET, 25%). The samples from the shallow phreatic aquifer contained more MPs than the samples from the deeper borehole, which contained fewer MPs and categories. This is to be expected, since the phreatic aquifer (a) is generally more contaminated, as it is close to human activities that generate MPs and its infiltration depth is only a few metres, which means that many microplastics can infiltrate at such shallow depths, and (b) it is exposed to the atmosphere, so they can also be suspended in the air. On the other hand, it is interesting to note that MPs, especially PET and PE, were detected in the borehole sample, suggesting that MPs can migrate to greater depths through water infiltration. Chemical analyses of the groundwater samples revealed high values of E.C., Ca2+, Mg2+, Cl−, and Na+, which indicate that seawater intrusion is taking place in the coastal aquifer system of the Erasinos basin. The increased concentrations of NO3− and PO43− also indicate the impact of agricultural activities.

Biodegradable microplastics: Uptake by and effects on the rockpool shrimp Palaemon elegans (Crustacea: Decapoda)

Ingestion of microplastics can lead to deleterious consequences for organisms, as documented by numerous laboratory studies. The current knowledge is based on a multitude of effect studies, conducted with conventional fossil-based and non-degradable plastics. However, there is a lack of information about the acceptance and the effects of novel bio-based and biodegradable plastics. Biodegradable plastics are considered an alternative to conventional plastics and are showing rapidly growing production rates. Biodegradable plastics can disperse into the environment in the same way as conventional plastics do, becoming available to marine organisms. This study aims to provide new insights into the uptake and effects of biodegradable microplastics on marine invertebrates. Rockpool shrimp, Palaemon elegans, were fed with algal flakes coated with polylactic acid (PLA), polyhydroxybutyrate-co-valerate (PHBV) and conventional low-density polyethylene (LDPE) microparticles. Live observations showed that all of the different types of microplastics were ingested. After dissection of the shrimp, less LDPE particles were found in the stomachs than PLA and PHBV particles. This indicates a longer retention time of biodegradable microplastics compared to conventional microplastics. Presumably, less LDPE particles were ingested or evacuated from the stomach, probably by regurgitation. The ingestion of microparticles of all types of plastics induced enzymatic activity of short-chain carboxylesterases in the midgut glands of the shrimp. However, only PLA induced enzymatic activity of medium-chain carboxylesterases. Palaemon elegans showed no oxidative stress response after ingestion of microparticles, irrespective of polymer type. From our results we conclude that biodegradable plastics might have different effects than conventional plastics. The longer retention times of biodegradable plastics might enhance exposure to leaching additives and other harmful substances. Our study provides new insights into how biodegradable plastics might affect aquatic fauna and indicate that the use of biodegradable plastics needs to be reconsidered to some extent.

Enhanced long-term stability of stained microplastics with carbon nitride fluorescent polymer for tracking

Fluorescent labeling and imaging is a useful tool to track the temporal and spatial distribution of microplastics (MPs) with size and shape features. However, the limited fluorescently labeled MPs spheres, photo-bleaching and leaching of organic small molecular dyes hamper the tracking of MPs in the environment. In this work, phenyl-modified carbon nitride (PMCN) fluorescent polymer was prepared and applied for the staining of eight different types of MPs. The interface interaction mechanism between PMCN fluorescent polymer and MPs was investigated by the desorption experiments. The long-time photo-stability of the stained MPs against ultraviolet (UV) light irradiation, freeze-thaw cycles, various environmental factors and real environmental water samples was evaluated. The MPs stained with PMCN fluorescent polymer showed more robust stability than the common dye (Nile red) against the damage when exposure to UV light for 72 h, treatment with freeze-thaw cycles for 60 days, exposure to strong acid, strong alkali, high salinity, freshwater (river and lake) or seawater for 60 days. Results indicate PMCN fluorescent polymer is promising as a convenient, efficient and universal fluorescent tracer for visually tracking the migration and distribution of MPs in environmental water system.

Microplastics Biodegradation by Aspergillus flavus and Aspergillus versicolor

Microplastics (MPs) have indeed raised significant concerns due to their widespread presence and potential adverse effects on both the environment and human health. This study aims to illuminate crucial aspects of MPs, including their origins, migration behavior, and the potential for bioremediation as an effective strategy for their removal. Microplastics can originate from various sources, such as the fragmentation of larger plastics, the presence of microbeads in personal care products, the shedding of fibers from textiles, industrial pellets, and products containing microplastics. These diverse sources contribute to the omnipresence of microplastics in both terrestrial and aquatic ecosystems. This study focuses on observing the biological degradation process of two fungi, Aspergillus flavus, and Aspergillus versicolor when exposed to three different types of microplastics: Polypropylene (PP), Polyethylene (PE), and Polystyrene (PS). After conducting experiments, removal efficiencies of A. flavus and A. versicolor were calculated. Based on the data collected during the 10th week of using these fungi, it was observed that A. flavus exhibited removal efficiencies of 18.3% for PE, 6.8% for PP, and 1.9% for PS. On the other hand, A. versicolor yielded removal efficiencies of 6.7% for PE, 5.1% for PP, and 3.3% for PS. It was determined that A. flavus and A. versicolor exhibited the highest biodegradation efficiency when targeting microplastic PE, while their effectiveness was relatively lower when dealing with microplastic PS.

Effects of degradable and non-degradable microplastics and oxytetracycline co-exposure on soil N2O and CO2 emissions

Microplastics and antibiotics are emerging contaminants that can elicit considerable adverse effects on carbon and nitrogen cycles and greenhouse gas emissions. The effect of the combined occurrence of antibiotics and different types of microplastics on soil ecosystem is poorly understood. We investigated the effects of oxytetracycline (OTC), polylactic acid (PLA) microplastics, and polyethylene (PE) microplastics alone and in combination on plant root growth traits, soil extracellular enzymatic activity, and nitrous oxide (N2O) and carbon dioxide (CO2) emissions from the soil. Plant root growth traits including root area, root surface area, root volume and root branches were negatively affected by all treatments; soil extracellular enzymatic activity was also negatively affected by all treatments expect for the cellobiohydrolase. The results showed that CO2 emission increased in all treatments, with a maximum increase of 505 % in the PLA treatment; however, N2O emissions increased in the OTC treatment by 44 % but decreased in all other treatments as compared to the control. Furthermore, partial least squares path modeling analysis suggested that soil extracellular enzymes significantly influenced soil N2O and CO2 emissions (P < 0.05) and had a strong correlation with root growth traits (P < 0.05). We thus concluded that changes in soil extracellular enzymatic activities and plant root growth traits, which were affected by different microplastic and antibiotic treatments, influenced soil CO2 and N2O gas emissions.

Exploring the origin and fate of surface and sub-surface marine microplastics in the Canary Islands region

The presence of different types of microplastics (MPs) in the Atlantic Ocean has been well-documented, with data collected from the Canary Islands indicating high concentrations of MPs at four different beaches (hot spots). However, critical gaps persist regarding the abundance of MPs in diverse open ocean regions, at varying depths, and their transport behavior and origin. This study aims to evaluate, for the first time, the large-scale (&amp;gt;100 km) and mesoscale (10-100 km) ocean dynamic processes and the resulting transport of MPs in the region. On the one hand, this study investigates the surface velocity of currents between 27-32°N latitude range, establishing correlation with the accumulation of MPs on diverse beaches across several islands of the archipelago. This analysis goes beyond studying the predominant current by integrating data at a smaller geographical scale over a two-year period. Concurrently, previous and ongoing research suggests the presence of small MPs (SMPs,&amp;lt;1 mm) at high concentration at a depth of 1100 meters in this region. By integrating these vertical profiles of MPs with a deep understanding of the physical processes of the Canary region accumulated over decades of research, our study introduces an innovative model that outlines how SMPs are sink and transported in open oceans by water mases. This comprehensive approach not only enhances our understanding of the complex dynamics influencing the distribution of MPs but also provides crucial insights to address the widespread problem of MP pollution in the Atlantic.

Polylactic acid microplastics have stronger positive effects on the qualitative traits of rice (Oryza sativa L.) than polyethylene microplastics: Evidence from a simulated field experiment

Soil pollution by microplastics (MPs) from different types of agricultural films has received substantial attention due to its potential effects on crop quality. To date, the effects of different types of MPs on rice grain quality and their underlying molecular mechanisms have not been clarified. In this study, we examined the effects of polyethylene MPs (PE-MPs) and biodegradable polylactic acid MPs (PLA-MPs) on rice grain quality at the environmental level (0.5 %) and evaluated the molecular mechanism through transcriptome analysis. PE- and PLA-MPs increased the number of rice grains per plant by 19.83 % and 24.66 %, respectively, and decreased the rice empty-shell rate by 55.89 % and 26.53 %, respectively. However, PLA-MPs increased the 1000-seed weight by 11.37 %, whereas PE-MPs had no obvious impact in this respect. Furthermore, MP exposure, especially that of PE-MPs, affected the content of mineral elements, fatty acids, and amino acids of rice grains by disturbing the expression of genes related to these functions and metabolism. Our findings provide insights into the response of rice grains to the stress caused by different MPs.

Effects of microplastics on N2O production and reduction potential in crop soils of northern China

Microplastics (MPs) pollution are found to be increasing in vegetable soils and potentially affecting N2O production and their associated pathways; however, its specific effects remain unclear. Here, we selected two common MPs, PE and PP at four different concentration levels of 0, 0.5, 1.5 and 3%, and conducted several incubation experiments aiming to explore soil bacterial and fungal N2O production. Results showed that the bacteria were the main contributors for the production of N2O, regardless of the absence or presence of MPs; and its contribution was decreased with increasing concentrations of PE and PP. The nosZ clade I and II genes were positively correlated with N2O reduction rates, indicating a combined regulation on soil N2O reduction. PE significantly inhibited the bacterial nitrification and denitrification, but did not affect the total N2O production rates; while PP significantly reduced both the bacterial and fungal N2O production rates. The resistance of fungal N2O production to MPs pollution was stronger than that of the bacterial N2O production. It highlights that the MPs pollution could reduce the potential of N2O production and reduction, and thus disturb soil nitrogen cycling system; while the inhibition on N2O production via bacteria and fungi varies with different types of MPs. This study is conducive to an improved and more comprehensive understanding of the ecological impacts of MPs within the agroecosystem.