A review on microplastics separation techniques from environmental media

A critical review on the migration, transformation, sampling, analysis and environmental effects of microplastics in the environment

As emerging pollutants, microplastics have recently received considerable attention owing to detection in various organisms and environments. Mass production and widespread use of plastic products increase their potential risks to humans owing to their persistent, mobile, and toxic properties. Numerous methods have been used to identify and quantify the various forms of microplastics, however, unified standards do not exist. In this review, we systematically summarize the sources, migration, transformation, and analytical methods for microplastics in diverse ecosystems, particularly the most recent sampling and identification techniques. Additionally, the environmental effects and health hazards of microplastics on aquatic and terrestrial systems, as well as human beings are discussed. We also present management strategies for reducing microplastics in a broader social and policy context. This review aims to provide an overview of the migration, transformation, sampling, analysis, and environmental effects of microplastics, which addresses knowledge gaps in microplastic pollution and provides proposals for key research gaps.

A critical review of sampling, extraction and analysis methods for tyre and road wear particles

Tyre and road wear particles (TRWPs) have become an increasing contamination concern because of their extensive distribution in the environment. A comprehensive overview of the methods for sampling, treatment and analysis of environmental samples for TRWPs (and their benefits and limitations) is lacking. We evaluate and critically assess the sampling, treatment and analysis methods previously reported for water, air, road dust and sediment/soil samples. We suggest research frameworks for studying TRWPs in these media. Microscopy and thermal analysis techniques such as scanning electron microscopy (with energy dispersive X-ray analysis), environmental scanning electron microscopy, 2-dimensional gas chromatography mass spectrometry and liquid chromatography with tandem mass spectrometry in the case of complex samples, are optimal methods for determination of the number and mass of TRWPs. Issues for further investigation and analysis recommendations are provided.

Unveiling the toxicity of micro-nanoplastics: A systematic exploration of understanding environmental and health implications

The surge in plastic production has spurred a global crisis as plastic pollution intensifies, with microplastics and nanoplastics emerging as notable environmental threats. Due to their miniature size, these particles are ubiquitous across ecosystems and pose severe hazards as they are ingested and bioaccumulate within organisms. Although global plastic production has reached an alarming 400.3 MTs, recycling efforts remain limited, with only 18.5 MTs being recycled. Currently, out of the total plastic waste, 49.6 % is converted into energy, 27 % is recycled, and 23.5 % is recovered as material, indicating a need for better waste management practices to combat the escalating pollution levels. Research studies on micro-nanoplastics have primarily concentrated on their environmental presence and laboratory-based toxicity studies. This review critically examines the sources and detection methods for micro-nanoplastics, emphasising their toxicological effects and ecological impacts. Organisms like zebrafish and rats serve as key models for studying these particle's bioaccumulative potential, showcasing adverse effects that extend to DNA damage, oxidative stress, and cellular apoptosis. Studies reveal that micro-nanoplastics can permeate biological barriers, including the blood-brain barrier, neurological imbalance, cardiac, respiratory, and dermatological disorders. These health risks, particularly relevant for humans, underscore the urgency for broader, real-world studies beyond controlled laboratory conditions. Additionally, the review discusses innovative energy-harvesting technologies as sustainable alternatives for plastic waste utilisation, particularly valuable for energy-deficient regions. These strategies aim to simultaneously address energy demands and mitigate plastic waste. This approach aligns with global sustainability goals, providing a promising avenue for both pollution reduction and energy generation. The review calls for further research to enhance detection techniques, assess long-term environmental impacts, and explore sustainable solutions that integrate energy recovery with pollution mitigation, especially in regions most affected by both energy shortages and increased plastic waste.

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).

From bulk to bits: understanding the degradation dynamics from plastics to microplastics, geographical influences and analytical approaches

The popularity of plastics in major application sectors is creating an increasing burden of pollutants in the environment in the forms of plastics and microplastics. More than 6 billion tons of plastics now reside in the environment, which is now an available source of secondary microplastics. Research focused on the degradation of plastics/microplastics dealing with different environmental conditions and their change in properties. Despite being a serious pollutant, sufficient resources are still missing for the transformation of secondary microplastics from large plastics and how to detect the level of degradation before this transition. This article's brief review provides insight into the current scenario of plastics, disposed waste plastics, management system, and their limitations. In addition, a detailed explanation of the transition of plastics to microplastics, their mechanism, and the effect of different geographical conditions on degradation is also demonstrated. Moreover, the available analytical techniques to understand the degradation index of different polymers are also described in addition to the future perspectives for research in this area. This review could provide valuable insight into the formation of microplastics from waste plastics and their mechanisms in addition to a comprehensive knowledge of the quantification of the degradation.

A HoLDI mass spectrometry platform for airborne nanoplastic detection

There are no established protocols for nanoplastic detection within complex environmental matrices. Mass spectrometry (MS) analysis of environmental nanoplastics is impeded by methodological constraints. We present a versatile platform evolved from matrix-assisted laser desorption/ionization (MALDI) MS for airborne nano/microplastic research. The 3D-printed hollow-laser desorption/ionization (HoLDI) target enables efficient, high-throughput analysis of aerosols collected on simple substrates without pre/post-treatments. HoLDI-MS determines the chemical composition and relative quantity of real-world airborne nano/microplastics, while used with conventional portable samplers and particle analyzers. Polyethylene, polyethylene glycol, and polydimethylsiloxanes are detected in an indoor environment, with a higher amount in the micro-sized range. Polycyclic aromatic hydrocarbons present in an outdoor setting, with a higher quantity in the nano-sized range. Morphological and elemental data provide additional evidence for observed contaminants and support multidisciplinary research interests. HoLDI holds promise as a standardized analytical framework for any air or water samples, facilitating research harmonization worldwide.

Efficient and stable extraction of nano-sized plastic particles enabled by bio-inspired magnetic "robots" in water

In this research, a rationally-designed strategy was employed to address the crucial issue of removing nano-plastics (NPs) from aquatic environments, which was based on fabricating sea urchin-like structures of Fe3O4 magnetic robots (MagRobots). Through imitating the sea urchin's telescopic tube foot movement and predation mechanism, the unique structures of the MagRobots were designed to adapt to the size and surface interactions of NPs, leading to a high efficiency of NPs removal (99%), as evidenced by the superior performance of 594.3 mg/g for the removal of polystyrene (PS) nanoparticles from water, with 3300% increase over magnetic Fe3O4 without structural design. The adsorption process was further analyzed using density functional theory (DFT) models and adsorption experiments, indicating that it was driven by electrostatic interactions. MagRobots maintained an adsorption capacity of up to 328 mg/g over four cyclic experiments and demonstrated high-capacity adsorption (close to 400 mg/g) in natural water bodies. The results of the simulations were supported by experiments that verified the excellent adsorption performance, regeneration effect, and environmental stability of the MagRobots under both simulated and real-world water conditions. This ingenious structural strategy provided valuable perspectives for the development of efficient magnetic porous materials for wastewater treatment, which would have potential applications for the treatment of NPs in real aquatic ecosystems. The unique sea urchin-like structures of the MagRobots could offer an innovative approach to tackle the challenge of NPs removal.

Assessment of microplastics and associated ecological risk in the longest river (Godavari) of peninsular India: A comprehensive source-to-sink analysis in water, sediment and fish

Persistent microplastics (MPs) accumulation in the aqueous environments is considered a threat to the ecosystem, potentially harming aquatic species and human health. In view of the escalating problem of MPs pollution in India, a comprehensive investigation of MPs accumulation in major riverine systems is necessary. The current study aims to estimate MPs abundance in surface water, sediment, and fish samples along the entire stretch of Godavari, the largest river in peninsular India. Average MPs concentrations in water lie in the range of 311-939 MPs/m3 and 2-144 MPs/kg d.w. for sediment. Urban regions and dam reservoirs showed elevated MPs abundance, emphasizing the impact of anthropogenic activities. The μ-Raman analysis revealed PE and PP were the abundantly occurring polymers in all matrices. Polymer and ecological risk index identify most sampling sites as extremely high-risk zones, posing a potential threat to aquatic ecosystems and human health. Plotted t-SNE (t-distributed Stochastic Neighbour Embedding) revealed similarities in MPs morphology and compositions among water, sediment and fish samples. Examined MPs in edible (flesh+skin) and inedible parts (GIT and gills) of seven different fish species showed a higher average MPs abundance in edible parts (10.7 ± 14.9 MPs/fish) than gills (7 ± 8.1 MPs/fish) and GIT (6.6 ± 5.5 MPs/fish). This suggests that removing gills and GIT from fish doesn't eliminate the consumer's risk of MPs intake. Overall, our work highlights the significant MPs pollution in the Godavari River, further providing essential data on the ecological risk of MPs to guide municipal action plans, improve waste management, target high-risk areas, and raise awareness to mitigate impacts.

Degradation of floor finishing materials owing to continuous gait: A comprehensive study on the generation and impact of microplastics

With the increasing concern regarding the effects of microplastics (MPs) on human health, it is essential to conduct research on the MPs generated in the atmosphere and on those occurring in indoor environments. One of the causes of particle generation in indoor spaces is the degradation of floor finishing materials, including human gait factor. Therefore, gait simulation experiments were conducted to verify the occurrence of MPs during the gait process. After the experiments, the concentrations of MPs were calculated, and the differences in the concentrations under various gait and floor finishing material conditions were analyzed. Moreover, the morphological analysis of MPs indicates the mechanisms of MPs generation. Additionally, a chemical bond analysis of MPs and surface analysis of floor finishing materials demonstrated the types and sources of MPs generation. Furthermore, the health risk assessment results showed that the health effect of MPs was the lowest in the case of marmoleum flooring, approximately 1.27 and 5.77 times lower than that of laminate flooring and carpet tiles, respectively. Consequently, the study demonstrated that MPs are generated owing to the surface degradation caused by gait and also provided insights into which floor finishing material is least affected by MPs.

Enhanced density separation efficiency of microplastics in presence of nonionic surfactants

Microplastics (MPs) recycling, a promising approach to tackle its pollution, faces significant challenges due to the lack of effective separation methods. Herein, the optimized density separation accompanied with nonionic surfactants was employed to purify single MPs species from mixed systems. By adjusting the flotation fluid density, the single MPs can be separated from their mixtures in equal proportions (e.x., 97 ± 2% pure polyethylene terephthalate (PET) was extracted from polystyrene (PS)/PET mixed system). Under the optimized density separation conditions, nonionic surfactants of Tween 20 (TW20) enhanced the purity of the separated MPs for all MPs mixture systems (from 69%-85% to 76%-96%). The enhanced separations can be mainly attributed to adsorption of surfactant onto the surface of MPs which would alter hydrophilic and hydrophobic properties of MPs. But anionic surfactants could reduce or promote the separated efficiencies of MPs (e.x., the purity of separated polyvinylchloride increased by 4.8% in Thermoplastic polyurethanes/polyvinylchloride group by added sodium dodecyl benzene sulfonate, and the purity of PS decreased by 8.3% in PS/PET group in presence of hexadecyl trimethyl ammonium bromide). The efficient separations have also been obtained in simulated environmental aqueous experiments where TW20 promoted the separated purity of PET from 83.4% to 91.8% in the PS/PET group, consistent with the separation effect in the laboratory environment. This paper provided a convenient and cost-effective method to separate mixed MPs to high-purity MPs, which would be improve the quality of plastic recycling.

Assessing Hydrocyclone System's Efficiency in Water-Borne Microplastics Capture Using Online Microscopy Sensors

Plastic pollution has been a global concern. Microplastics are often referred to as plastic particulates whose sizes are within the range of 1 μm to 5 mm. To cost-effectively capture these tiny microplastics from open environments, such as from the air or aquatic/marine systems, is far from trivial. Not only is some innovative capturing technology demanded, but some online monitoring solutions are often requested as well to assess the capturing effectiveness and efficiency, as well as provide some feedback information to the control system to adapt to varying operating conditions. Inspired by the de-oiling treatment of the produced water in offshore oil & gas production, this paper explores the potential to apply the hydrocyclone technology to cost-effectively handle the water-borne microplastics, and its effectiveness is demonstrated based on reliably calibrated online microscopy measurements subject to artificial polyethylene particulates added to the water stream. The experimental work is carried out using a commercial de-oiling hydrocyclone system and a set of commercial optical microscopy sensors. A statistic-based calibration method is firstly proposed for the deployed microscopy sensors to select the best calibration parameters. Afterwards these sensors are installed at the inlet and water-outlet of the hydrocyclone system via a side-stream sampling mechanism to assess this system's (microplastics) separation efficiency subject to dynamical operating conditions, which are mimicked by manipulating its underflow and overflow control valves via PI-controlled loops. The separation efficiencies are calculated based on these volume concentration measurements and compared between the case with (statistically) optimal calibration parameters and the case with a set of non-optimal parameters. The best separation efficiency of 87.76% under the optimal calibration parameters is observed under a specific operating condition. The obtained result shows a promising potential to use these separation and sensing systems to cost-effectively handle aquatic microplastics collection, though it also indicates that a further higher efficiency could be achieved by some (microplastics) dedicated cyclone design combined with a dedicated process control system, and this is one part of our ongoing research work.

Optimising microplastic polyethylene terephthalate fibre extraction from sediments: Tailoring a density-separation procedure for enhanced recovery and reliability

Despite the presence of microplastics in sediments being widely acknowledged, the absence of standardised processing methods in extracting microplastics can compromise reliable and comparable results. Density separation is a predominant method for extracting microplastics from sediments. In this study, Sodium Polytungstate (ρ = 1.6 g cm-3) was selected as the density separation agent for three key factors: i) optimal density for extracting common plastic polymers, ii) low toxicity, and iii) recycling potential of the solution. It is therefore cost-effective, and the risk of solution dispersal is minimal. The solution was tested through four separation procedures, extracting PET fibres from three artificial sediment mixtures (i.e., pure sand, pure mud, and 50 % sand and 50 % mud). The results indicate that the solution employed in this work is highly effective for extracting microplastic fibres from sediments, with recovery rates up to 99 %. However, the results highlight differences in the recovery among the four procedures and in terms of the sediment characteristics. Specifically, extracting microplastics was easier in sandy sediment samples than in mud-rich ones. The complexity of extracting microplastics from mud-rich sediments results from i) the creation of microplastic-sediment aggregates forming denser structures, that settle down trapping microplastics in sediments; ii) the development of a clay sediment cap that hinders the rise of microplastics to the surface. Reducing the risk of underestimation of microplastic content in mud-rich samples can be accomplished by applying a procedure that involves placing the samples with the Sodium Polytungstate solution on a stirring plate while progressively lowering the rotation velocity. Using this method, cohesive sediments lose their ability to trap microplastics while aggregating, consequently reducing their ability to drag microplastics to the bottom. This facilitated microplastics to reach the liquid surface, thereby enabling an efficient retrieval even in mud-rich samples.

Challenges in Raman spectroscopy of (micro)Plastics: The interfering role of colourants

Rising plastic consumption leads to widespread microplastic (MP) contamination. Raman spectroscopy is widely used for MP identification due to its ability to analyse particles as small as 1 μm. However, it faces challenges such as interference from pigments and additives. In this study, we aim to assess the accuracy of Raman micro-spectroscopy in identifying coloured plastic samples by applying various oxidative treatments to eliminate the possible interference effect caused by colourants associated with the sample. Standard and coloured microplastics were analysed using a Raman imaging microscope. Coloured plastics were treated with H2O2 30%, Sodium hypochlorite 5%, and Fenton reagent (H2O2 30% and Ferrous sulphate 0.2 M) for 24, 48, and 72 h. The Raman spectra were acquired after treatment to assess the impact of the treatment procedure on the polymer identification. Our results revealed that colourants significantly impact Raman spectra by peak broadening and/or fluorescence effects, which reduces identification accuracy and match scores Red pigments particularly obscure polymer identification. Treatments like oxidation and Fenton's reagent showed limited effectiveness. Additives in plastic samples can affect the accuracy of polymer identification by the Raman spectroscopy technique. Common treatment procedures do not improve the accuracy of identification. In order to improve the reliability of Raman analysis, essential factors such as utilizing multiple excitation lasers and appropriate CCD detectors, establishing a comprehensive reference library of colourants and additives, and employing advanced techniques like time-gated Raman spectroscopy or Surface-Enhanced Raman Spectroscopy (SERS) should be considered.

Modeling the differential functional responses and selectivity of a marine copepod to nano/microplastics in mixture

Nano- and microplastics (NMPs) pollution is widespread in the oceans, posing potential risks to marine species. This study examined the accumulation capacity and selectivity potentials of NMPs by a marine copepod Parvocalanus crassirostris under different food mixtures by modeling the combined biokinetic and functional response. We investigated two sizes of NMPs (200 nm and 5 µm) across a concentration gradient (0 - 5000 µg/L) and varying diatom abundances (0, 104, 105 cells/mL). Fluorescence imaging and quantification revealed that P. crassirostris actively ingested NMPs at low concentration. Accumulation increased with NMPs concentration but eventually saturated due to gut capacity limits, following a Holling type II functional response (i.e., hyperbolic curve). Our novel functional response model estimated the key parameters and demonstrated that the maximum accumulation reached 5.3 % of dry weight with averaged half-saturation constants of 229 µg/L. The size of NMPs did not significantly affect the total accumulation or satiety levels. The presence of diatoms influenced the feeding selectivity and decreased the microplastic accumulation by 73 % at 105 cells/mL, while facilitating nanoplastic accumulation by 81 % at 104 cells/mL. This study enhanced our understanding of NMPs bioavailability and environmental fate in marine ecosystems.

First report of microplastics in water and sediments of the alkaline Bagno dell'Acqua Lake (Pantelleria Island, southern Italy)

Microplastics are ubiquitous in aquatic ecosystems and lakes are considered important sinks for this contaminant. In this study, we assessed for the first time the occurrence and spatial distribution of microplastics in surficial waters and sediment of a small alkaline lake located in the National Park of Pantelleria Island (Central Mediterranean Sea). The island is small, scarcely populated, not industrialized and ∼70 km far from the southern European and northern African shores. Water samples were collected in triplicates in different sectors of the lake using a 10 L metal bucket, while sediment sampling was carried out at seven stations along the lake shoreline, plus one station at 3.6 m depth. Results show a homogeneous distribution of microplastic in surface waters, dominated by fibers (∼90%), with a mean concentration of 0.13 ± 0.04 MP/L, which is lower than most of the lakes worldwide. Conversely, microplastics in sediment had a higher proportion of fragments and films (50%) and their concentrations range from 0 to 540 MP/kg. The highest abundance was recorded in the western sector, where most of touristic activities concentrate, and at the 3.6 m depth station, thus suggesting that the deeper parts of the lake may retain the majority of microplastics entering the system. This study shows that even in small lakes far from major anthropic pressures, sediment may contain microplastics in striking abundances, pointing out the need to assess rural and remote lakes, at present much understudied compared to lakes in highly populated regions.

Exploring the effects of polyethylene and polyester microplastics on biofilm formation, membrane Fouling, and microbial communities in Modified Ludzack-Ettinger-Reciprocation membrane bioreactors

Microplastics (MPs) inevitably enter wastewater treatment plants (WWTPs), yet their impacts remain poorly understood. This study investigates the effects of MPs on system performance and membrane fouling in a Modified Ludzack-Ettinger (MLE)-Reciprocation Membrane Bioreactor (rMBR), an energy-efficient alternative to conventional membrane bioreactors. Additionally, the study examines changes in microbial community induced by different types and shapes of MPs-polyethylene (PE) pellets and polyester (PES) fibers- as well as biofilm formation on MPs, using next-generation sequencing. Results revealed that transmembrane pressure (TMP) increased 2-3 times faster in the presence of PE pellets, while TMP remained stable during the PES stage, implying that MP type and shape could influence biofouling behaviors. Furthermore, enhanced nitrate removal was observed in the aerobic tank due to denitrifying biofilm formation on MPs. However, PES MPs reduced nitrate removal efficiency from 99.6 ± 0.3 % to 90.9 ± 7.9 % and decreased the relative abundance of denitrifying bacteria. Numerous taxa showed affinity to PE pellets, including some pathogens, e.g., Norcadia and Mycobacterium. Notably, an uncultured phylum Candidatus Saccharibacteria dominated in membrane biofilm and MPs, reaching up to 37 % relative abundance. This study is the first to explore how different types and shapes of MPs affect membrane bioreactor systems, particularly with respect to microbial community structure and biofilm formation. The findings offer new insights into the influence of MPs on wastewater treatment processes and highlight the significance of the uncultured phylumCandidatus Saccharibacteriain membrane fouling.

The development of an analytical procedure for the determination of microplastics in freshwater ecosystems

Microplastics raise growing concerns regarding their ubiquity and possible negative impact on human health; therefore, the need for comparable, standardized methods is urgent. Modern instrumental analytical techniques, such as IR and Raman spectroscopy, pyrolysis-gas chromatography-mass spectrometry and electron microscopy, are fundamental for the analysis of microplastics in environmental and biological objects. The quality of the samples prepared is a determining factor in the validity of the results obtained. Based on our research, currently approaches to preparing environmental samples are time-consuming and need some improvements. To overcome this problem, a new method for the preparation of freshwater samples was developed. In our research, peracetic acid and its combination with Fenton's reagent were employed for the first time to prepare natural water samples. Furthermore, we proposed the use of a heavy liquid based on sodium heteropolyoxotungstate with a density of 1.70 g cm-3, which allows the extraction of polymers with high density and is non-toxic. The new approach was compared with the most commonly used sample preparation method (peroxide oxidation (30% H2O2 + 0.05 M Fe(II) solution)) and showed higher recovery efficiency for microplastic particles in both test and freshwater samples collected from the rivers Ob (Novosibirsk, Russia) and Berd (Berdsk, Russia). The obtained results are promising; the time spent on this procedure is no more than 3 hours, which is 6 to 12 times faster than the most widely used methods. In addition, this approach makes it possible to obtain samples suitable for subsequent analysis by any analytical instrumental method.

Numerical study on the mechanism of microplastic separation from water by cyclonic air flotation

Microplastics have attracted considerable attention as emerging contaminants that threaten water bodies. The removal of microplastics from a mini-hydrocyclone, enhanced by air flotation, was studied numerically. The three-phase flow was modeled using the Eulerian-Eulerian model coupled with interphase interactions. The characteristics of the flow field and distribution of microplastics and microbubbles were discussed, and the mechanism of cyclonic air flotation separation was analyzed. It was found that injecting microbubbles accelerated the axial migration of microplastics and moved the enriched area upward toward the overflow. The coalescence rate of the bubbles near the axis was higher than their breakage rate, which led to the formation of an air core. The length and diameter of the air core increased with the inlet gas holdup. When the air core size closely matched the overflow, the constrained flow channel prevented the discharge of microplastics. The optimal air holdup must be determined to ensure the efficiency of the cyclonic air flotation process. The sizes of the microbubbles used for cyclonic air flotation should be comparable to those of the separated microplastics. The upper cone angle significantly promoted the migration of microplastics to the axis. This study was conducted to purify microplastic-containing wastewater using an environmentally friendly and energy-efficient technique and to provide a theoretical basis and practical reference for applying microplastic separation technology in water.

Oleo-extraction of microplastics using flotation plus sol-gel technique to confine small particles in silicon dioxide gel

Extracting microplastics from natural sources is challenging, especially microplastics with sizes smaller than 100 μm. The flotation method is the most common microplastic extraction, but it struggles with fine particles due to the difficulty in collecting floating plastic particles from the liquid during the separation process. This study proposes a new floating media, tetraethyl orthosilicate (TEOS), that could separate microplastics using its hydrophobic-oleophilic properties. Most interestingly, TEOS transformed from a liquid state to a solid state (gel) by hydrolysis and condensation reactions, thus safely capturing the separated microplastic particles after flotation and mitigating particle loss from scooping since its gel acted as a particle holder. The average recovery rates obtained were in the range of 95-100% for polyethylene terephthalate, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polytetrafluoroethylene, and aged tyre rubber. The recovery rates were slightly reduced for finer particles (sizes down to 40 μm) at 82-98%. TEOS-based extraction provided a higher recovery rate for non-polar plastics than for polar or hydrophilic plastics. The separated microplastics maintained their characteristics for polymer identification, as proven by spectroscopic and thermal analysis techniques. Therefore, TEOS-based extraction could be a new approach to microplastic extraction, especially for preventing fine particle loss.

Micro plastics mapping in the agricultural sector of Cyprus

The impact of Microplastic Pollution (MPs) on human health, the environment, economy, and society has been previously investigated. However, there is a lack of comprehensive understanding regarding specific areas that require urgent measures to address marine pollution. The accumulation of MPs in Mediterranean coastal environments is particularly noteworthy. This is attributed to the region's economic reliance on tourism and the decline of popular tourist destinations caused by the presence of coastal and marine waste. The objective of the present research was to conduct a strategic analysis and mapping of MPs from soil samples taken from rural areas of Cyprus. Within the framework of the present research, a general picture of the status of MP pollution in areas covering significant percentages in the domestic supply of fruits and vegetables was obtained. The survey indicated the presence of more than 70% of MPs in crops at a concentration of up to 1.5 %. As a result of this research, the need to highlight the importance of the rational use of plastics and proper management to mitigate pollution is a primary concern. The rational separation of materials for recycling, information, reuse of materials, processing, and an increase in the number of recycling bins in public places are considered urgent. Cooperation between the state, institutions and industry must be based on the protection of people and the environment.

All black: a microplastic extraction combined with colour-based analysis allows identification and characterisation of tire wear particles (TWP) in soils

While tire wear particles (TWP) have been estimated to represent more than 90% of the total microplastic (MP) emitted in European countries and may have environmental health effects, only few data about TWP concentrations and characteristics are available today. The lack of data stems from the fact that no standardized, cost efficient or accessible extraction and identification method is available yet. We present a method allowing the extraction of TWP from soil, performing analysis with a conventional optical microscope and a machine learning approach to identify TWP in soil based on their colour. The lowest size of TWP which could be measured reliably with an acceptable recovery using our experimental set-up was 35 µm. Further improvements would be possible given more advanced technical infrastructure (higher optical magnification and image quality). Our method showed a mean recovery of 85% in the 35-2000 µm particle size range and no blank contamination. We tested for possible interference from charcoal (as another black soil component with similar properties) in the soils and found a reduction of the interference from charcoal by 92% during extraction. We applied our method to a highway adjacent soil at 1 m, 2 m, 5 m, and 10 m and detected TWP in all samples with a tendency to higher concentrations at 1 m and 2 m from the road compared to 10 m from the road. The observed TWP concentrations were in the same order of magnitude as what was previously reported in literature in highway adjacent soils. These results demonstrate the potential of the method to provide quantitative data on the occurrence and characteristics of TWP in the environment. The method can be easily implemented in many labs, and help to address our knowledge gap regarding TWP concentrations in soils.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43591-024-00102-9.

Cost-Effective and Wireless Portable Device for Rapid and Sensitive Quantification of Micro/Nanoplastics

The accumulation of micro/nanoplastics (MNPs) in ecosystems poses tremendous environmental risks for terrestrial and aquatic organisms. Designing rapid, field-deployable, and sensitive devices for assessing the potential risks of MNPs pollution is critical. However, current techniques for MNPs detection have limited effectiveness. Here, we design a wireless portable device that allows rapid, sensitive, and on-site detection of MNPs, followed by remote data processing via machine learning algorithms for quantitative fluorescence imaging. We utilized a supramolecular labeling strategy, employing luminescent metal-phenolic networks composed of zirconium ions, tannic acid, and rhodamine B, to efficiently label various sizes of MNPs (e.g., 50 nm-10 μm). Results showed that our device can quantify MNPs as low as 330 microplastics and 3.08 × 106 nanoplastics in less than 20 min. We demonstrated the applicability of the device to real-world samples through determination of MNPs released from plastic cups after hot water and flow induction and nanoplastics in tap water. Moreover, the device is user-friendly and operative by untrained personnel to conduct data processing on the APP remotely. The analytical platform integrating quantitative imaging, customized data processing, decision tree model, and low-cost analysis ($0.015 per assay) has great potential for high-throughput screening of MNPs in agrifood and environmental systems.

Micro- and Nanoplastics Produced from Textile Finishes: A Review

The problem of increasing plastic pollution has emerged as a significant societal issue. Plastics can originate from various sources, and there is growing concern among researchers to study and investigate this new category of pollution. The plastic waste is found at the macro, micro, and nanoscale, and its study has had great significance according to the perspective of posing hazardous impacts on living organisms. Given the high demand for functional textiles, the textile industries are supporting the coating of different polymeric based finishes on the surface of textile products. The plastic debris emitted from these coated finishes are in the ranges of nanometric scale, so-called polymeric nanoplastics (PNPs). With the new terminology, polymeric nanoplastics (PNPs) released from textile finishes or coatings are being increasingly mentioned, and the term fibrous microplastics (FMPs) can be seen as outdated. This study is based on an intensive review of a very novel category of debris plastics (PNPs) mostly produced from textile finishes or coatings. In fact, FMPs and PNPs released from synthetic textiles and textiles coated with plastic-based finishes during washing activities are considered to be a major cause that contributes to the current overall load of microplastics (MPs) in the environment. A link between the concentration of NPs from textile fibers and NPs from textile polymeric-based coatings in freshwater and sediments within a particular local setting and the extent of activities of the textile industry has been demonstrated. Invested efforts have been paid to consider and concentrate on plastic pollution (nanoplastics from textile polymeric coatings). We also summarize existing methodologies to elucidate the identification and proactive quantification of nanoplastics shed from the textile polymeric coatings. To this end, more than 40 studies have been done to identify the physical, chemical, and mechanical parameters and to characterize nanoplastics.

Microplastics in aquatic systems: An in-depth review of current and potential water treatment processes

Plastic products, despite their undeniable utility in modern life, pose significant environmental challenges, particularly when it comes to recycling. A crucial concern is the pervasive introduction of microplastics (MPs) into aquatic ecosystems, with deleterious effects on marine organisms. This review presents a detailed examination of the methodologies developed for MPs removal in water treatment systems. Initially, investigating the most common types of MPs in wastewater, subsequently presenting methodologies for their precise identification and quantification in aquatic environments. Instruments such as scanning electron microscopy, dynamic light scattering, Fourier transform infrared spectroscopy, Raman spectroscopy, surface-enhanced Raman spectroscopy, and Raman tweezers stand out as powerful tools for studying MPs. The discussion then transitions to the exploration of both existing and emergent techniques for MPs removal in wastewater treatment plants and drinking water treatment plants. This includes a description of the core mechanisms that drive these techniques, with an emphasis on the latest research developments in MPs degradation. Present MPs removal methodologies, ranging from physical separation to chemical and biological adsorption and degradation, offer varied advantages and constraints. Addressing the MPs contamination problem in its entirety remains a significant challenge. In conclusion, the review offers a succinct overview of each technique and forwards recommendations for future research, highlighting the pressing nature of this environmental dilemma.

The exploitation of bio-electrochemical system and microplastics removal: Possibilities and perspectives

Microplastic (MP) pollution has caused severe concern due to its harmful effect on human beings and ecosystems. Existing MP removal methods face many obstacles, such as high cost, high energy consumption, low efficiency, release of toxic chemicals, etc. Thus, it is crucial to find appropriate and sustainable methods to replace common MP removal approaches. Bio-electrochemical system (BES) is a sustainable clean energy technology that has been successfully applied to wastewater treatment, seawater desalination, metal removal, energy production, biosensors, etc. However, research reports on BES technology to eliminate MP pollution are limited. This paper reviews the mechanism, hazards, and common treatment methods of MP removal and discusses the application of BES systems to improve MP removal efficiency and sustainability. Firstly, the characteristics and limitations of common MP removal techniques are systematically summarized. Then, the potential application of BES technology in MP removal is explored. Furthermore, the feasibility and stability of the potential BES MP removal application are critically evalauted while recommendations for further research are proposed.

Challenges and Recent Analytical Advances in Micro/Nanoplastic Detection

Despite growing ecological concerns, studies on microplastics and nanoplastics are still in their initial stages owing to technical hurdles in analytical techniques, especially for nanoplastics. We provide an overview of the general attributes of micro/nanoplastics in natural environments and analytical techniques commonly used for their analysis. After demonstrating the analytical challenges associated with the identification of nanoplastics due to their distinctive characteristics, we discuss recent technological advancements for detecting nanoplastics.

Influence of microplastics and environmentally persistent free radicals on the ability of biochar components to promote degradation of antibiotics by activated peroxymonosulfate

Microplastics (MPs) in sludge can affect the ability of biochar-activated peroxymonosulfate (PMS) to degrade antibiotics. In this work, biochar was prepared by mixing sludge and polystyrene (PS) through hydrothermal carbonization (HTC) and high-temperature pyrolysis processes. The resulting biochar was used to activate PMS to degrade ofloxacin (OFX), levofloxacin (LEV), and pefloxacin (PFX). The addition of PS significantly enhanced the ability of biochar/PMS to degrade antibiotics and the levels of environmentally persistent free radicals (EPFRs, 4.59 × 1020 spin/g) due to the decomposition of PS. The addition of PS resulted in a slight decrease in the specific surface area of biochar (2-3 m2/g on average), but a significant increase in the concentration of EPFRs increased the removal efficiency. The activation of PMS by biochar is dominated by free radicals, accounting for about 70%, in which SO4•- and •OH contribute the most and O2•- the least. However, 1O2 contributes 15-20% to the degradation of antibiotics in non-free radical processes. Overall, the process of biochar/PMS degradation of antibiotics is mainly dominated by free radicals, and the effect of non-free radicals is not obvious. Both hydrochar and pyrocarbon samples showed good hydrophilicity, and this property should improve the ability of active sites on biochar to degrade antibiotics. In the HTC process, PS can decompose during hydrochar preparation, with a maximum reduction value of 40.09%. The three-dimension excitation emission matrix fluorescence spectroscopy (3D-EEM) and total organic carbon (TOC) results show that the protein content in sludge plays a major role in reducing PS, with little effect of polysaccharide and SiO2. There are six to seven degradation intermediates of quinolone antibiotics, which are eventually degraded into CO2, H2O, and inorganic substances. The regeneration experiment showed good reusability of hydrochar and pyrocarbon, further demonstrating the suitability of biochar for the degradation of antibiotics.

Colloidal Engineering of Microplastic Capture with Biodegradable Soft Dendritic "Microcleaners"

The introduction of colloidal principles that enable efficient microplastic collection from aquatic environments is a goal of great environmental importance. Here, we present a novel method of microplastic (MP) collection using biodegradable hydrogel soft dendritic colloids (hSDCs). These dendritic colloids have abundant nanofibrils and a large surface area, which provide an abundance of interfacial interactions and excellent networking capabilities, allowing for the capture of plastic particles and other contaminants. Here, we show how the polymer composition and morphology of the hSDCs can impact the capture of microplastics modeled by latex microbeads. Additionally, we use colloidal DLVO theory to interpret the capture efficiencies of microbeads of different sizes and surface functional groups. The results demonstrate the microplastic remediation efficiency of hydrogel dendricolloids and highlight the primary factors involved in the microbead interactions and adsorption. On a practical level, the results show that the development of environmentally benign microcleaners based on naturally sourced materials could present a sustainable solution for microplastic cleanup.

Recent advances in the application of magnetic materials for the management of perfluoroalkyl substances in aqueous phases

Perfluoroalkyl substances (PFASs) are a class of artificially synthesised organic compounds extensively used in both industrial and consumer products owing to their unique characteristics. However, their persistence in the environment and potential risk to health have raised serious global concerns. Therefore, developing effective techniques to identify, eliminate, and degrade these pollutants in water are crucial. Owing to their high surface area, magnetic responsiveness, redox sensitivity, and ease of separation, magnetic materials have been considered for the treatment of PFASs from water in recent years. This review provides a comprehensive overview of the recent use of magnetic materials for the detection, removal, and degradation of PFASs in aqueous solutions. First, the use of magnetic materials for sensitive and precise detection of PFASs is addressed. Second, the adsorption of PFASs using magnetic materials is discussed. Several magnetic materials, including iron oxides, ferrites, and magnetic carbon composites, have been explored as efficient adsorbents for PFASs removal from water. Surface modification, functionalization, and composite fabrication have been employed to improve the adsorption effectiveness and selectivity of magnetic materials for PFASs. The final section of this review focuses on the advanced oxidation for PFASs using magnetic materials. This review suggests that magnetic materials have demonstrated considerable potential for use in various environmental remediation applications, as well as in the treatment of PFASs-contaminated water.

Understanding microplastic pollution: Tracing the footprints and eco-friendly solutions

Microplastics (MPs) pollution has emerged as a critical environmental issue with far-reaching consequences for ecosystems and human health. These are plastic particles measuring <5 mm and are categorized as primary and secondary based on their origin. Primary MPs are used in various products like cosmetics, scrubs, body wash, and toothpaste, while secondary MPs are generated through the degradation of plastic products. These have been detected in seas, rivers, snow, indoor air, and seafood, posing potential risks to human health through the food chain. Detecting and quantifying MPs are essential to understand their distribution and abundance in the environment. Various microscopic (fluorescence microscopy, scanning electron microscopy) and spectroscopy techniques (FTIR, Raman spectroscopy, X-ray photoelectron spectroscopy) have been reported to analyse MPs. Despite the challenges in scalable removal methods, biological systems have emerged as promising options for eco-friendly MPs remediation. Algae, bacteria, and fungi have shown the potential to adsorb and degrade MPs in wastewater treatment plants (WWTPs) offering hope for mitigating this global crisis. This review examines the sources, impacts, detection, and biological removal of MPs, highlighting future directions in this crucial field of environmental conservation. By fostering global collaboration and innovative research a path towards a cleaner and healthier planet for future generations can be promised.

Microplastic separation and enrichment in microchannels under derivative electric field gradient by bipolar electrode reactions

The decomposed plastic products in the natural environment evolve into tiny plastic particles with characteristics such as small size, lightweight, and difficulty in removal, resulting in a significant pollution issue in aquatic environments. Significant progress has been made in microplastic separation technology benefiting from microfluidic chips in recent years. Based on the mechanisms of microfluidic control technology, this study investigates the enrichment and separation mechanisms of polystyrene particles in an unbuffered solution. The Faraday reaction caused by the bipolar electrodes changes the electric field gradient and improves the separation efficiency. We also propose  an evaluation scheme to measure the separation efficiency. Finite element simulations are conducted to parametrically analyze the influence of applied voltages, channel geometry, and size of electrodes on plastic particle separation. The numerical cases indicate that the electrode-installed microfluidic channels separate microplastic particles effectively and precisely. The electrodes play an important role in local electric field distribution and trigger violent chemical reactions. By optimizing the microchannel structure, applied voltages, and separation channel angle, an optimal solution for separating microplastic particles can be found. This study could supply some references to control microplastic pollution in the future.

Microplastics and associated chemicals in drinking water: A review of their occurrence and human health implications

Microplastics (MPs) have entered drinking water (DW) via various pathways, raising concerns about their potential health impacts. This study provides a comprehensive review of MP-associated chemicals, such as oligomers, plasticizers, stabilizers, and ultraviolet (UV) filters that can be leached out during DW treatment and distribution. The leaching of these chemicals is influenced by various environmental and operating factors, with three major ones identified: MP concentration and polymer type, pH, and contact time. The leaching process is substantially enhanced during the disinfection step of DW treatment, due to ultraviolet light and/or disinfectant-triggered reactions. The study also reviewed human exposure to MPs and associated chemicals in DW, as well as their health impacts on the human nervous, digestive, reproductive, and hepatic systems, especially the neuroendocrine toxicity of endocrine-disrupting chemicals. An overview of MPs in DW, including tap water and bottled water, was also presented to enable a background understanding of MPs-associated chemicals. In short, certain chemicals leached from MPs in DW can have significant implications for human health and demand further research on their long-term health impacts, mitigation strategies, and interactions with other pollutants such as disinfection byproducts (DBPs) and per- and polyfluoroalkyl substances (PFASs). This study is anticipated to facilitate the research and management of MPs in DW and beverages.

Evaluating the performance of electrocoagulation system in the removal of polystyrene microplastics from water

Emerging pollutants, particularly microplastics, present a significant threat to both the environment and human health. Traditional treatment methods lack targeted strategies for their removal. This study thoroughly investigated the efficacy of electrocoagulation as a method for efficiently extracting microplastics from water. Various critical operational parameters, including electrode combinations, pH levels, electrolyte concentrations, electrode geometries, configurations, current intensities, and reaction times, were systematically examined. The study systematically examined the impact of different combinations of aluminium (Al) and stainless steel (SS) electrodes, including Al-Al, SS-SS, Al-SS, and SS-Al. Among these combinations, it was found that the Al-Al pairing exhibited outstanding efficiency in microplastic removal, while simultaneously minimizing energy consumption. Initial pH emerged as a critical parameter, with a neutral pH of 7 demonstrating the highest removal efficiency. In the pursuit of optimizing parameters like electrolyte concentrations, electrode geometry, and configuration, it's noteworthy that consistently achieving removal efficiencies exceeding 90% has been a significant achievement. However, to ascertain economic efficiency, additional factors such as energy consumption, electrode usage, and post-treatment conductivity must be taken into account. To tackle the complexity posed by various parameters and criteria, using multi-criteria decision-making tools like TOPSIS is essential, as it has a track record of effectiveness in practical applications. The electrolyte concentration of 0.5 g L-1 is identified as optimal by TOPSIS analysis Additionally, the TOPSIS highlighted the superiority of cylindrical hollow wire mesh electrodes and established the monopolar parallel configuration as the most effective electrode connection method. The investigation carefully evaluated the effect of reaction time, determining that a 50-min window provides optimal microplastic removal efficiency. This refined system exhibited remarkable proficiency in eliminating microplastics of varying size ranges (0-75 μm, 75-150 μm, and 150-300 μm), achieving removal efficiencies of 90.67%, 93.6%, and 94.6%, respectively, at input concentration of 0.2 g L-1. The present study offers a comprehensive framework for optimizing electrocoagulation parameters, presenting a practical and highly effective strategy to address the critical issue of microplastic contamination in aquatic environments.

Emerging isolation and degradation technology of microplastics and nanoplastics in the environment

Microplastics (MPs, less than 5 mm in size) are widely distributed in surroundings in various forms and ways, and threaten ecosystems security and human health. Its environmental behavior as pollutants carrier and the after-effects exposed to MPs has been extensively exploited; whereas, current knowledge on technologies for the separation and degradation of MPs is relatively limited. It is essential to isolate MPs from surroundings and/or degrade to safe levels. This in-depth review details the origin and distribution of MPs. Provides a comprehensive summary of currently available MPs separation and degradation technologies, and discusses the mechanisms, challenges, and application prospects of these technologies. Comparison of the contribution of various separation methods to the separation of NPs and MPs. Furthermore, the latest research trends and direction in bio-degradation technology are outlooked.

Conversion of PET Bottle Waste into a Terephthalic Acid-Based Metal-Organic Framework for Removing Plastic Nanoparticles from Water

Micro- and nanoparticles of plastic waste are considered emerging pollutants with significant environmental and health impacts at high concentrations or prolonged exposure time. Here we report the synthesis and characterization of a known metal-organic framework (MOF) using terephthalic acid (TPA) recovered from the hydrolysis of polyethylene terephthalate (PET) bottle waste. This approach adds value to the existing large amounts of bottle waste in the environment. Fully characterized zinc-TPA MOF (MOF-5) was used for the extraction and removal of engineered polyvinyl chloride (PVC) and polymethylmethacrylate (PMMA) nanoparticles from water with a high efficiency of 97% and 95%, respectively. Kinetic and isotherm models for the adsorption of polymer nanoparticles (PNPs) on the MOF surface were investigated to understand the mechanism. The Qmax for PVC and PMMA NPs were recorded as 56.65 mg/g and 33.32 mg/g, respectively. MOF-5 was characterized before and after adsorption of PNPs on the surface of MOF-5 using a range of techniques. After adsorption, the MOF-5 was successfully regenerated and reused for the adsorption and removal of PNPs, showing consistent results for five adsorption cycles with a removal rate of 83-85%. MOF-5 was characterized before and after adsorption of PNPs on the surface using a range of techniques. The MOF-5 with PNPs on the surface was successfully regenerated and reused for the adsorption and removal of polymer nanoparticles, showing consistent results for five extraction cycles. As a proof of concept, MOF-5 was also used to remove plastic particles from commercially available body scrub gel solutions. Such methods and materials are needed to mitigate the health hazards caused by emerging micro- and nanoplastic pollutants in the environment.

Recent advances on the methods developed for the identification and detection of emerging contaminant microplastics: a review

The widespread use of plastics, popular for their versatility and cost-efficiency in mass production, has led to their essential role in modern society. Their remarkable attributes, such as flexibility, mechanical strength, lightweight, and affordability, have further strengthened their importance. However, the emergence of microplastics (MPs), minute plastic particles, has raised environmental concerns. Over the last decade, numerous studies have uncovered MPs of varying sizes in diverse environments. They primarily originate from textile fibres and cosmetic products, with large plastic items undergoing degradation and contributing as secondary sources. The bioaccumulation of MPs, with potential ingestion by humans through the food chain, underscores their significance as environmental contaminants. Therefore, continuous monitoring of environmental and food samples is imperative. A range of spectroscopic techniques, including vibrational spectroscopy, Raman spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, hyperspectral imaging, and nuclear magnetic resonance (NMR) spectroscopy, facilitates the detection of MPs. This review offers a comprehensive overview of the analytical methods employed for sample collection, characterization, and analysis of MPs. It also emphasizes the crucial criteria for selecting practical and standardized techniques for the detection of MPs. Despite advancements, challenges persist in this field, and this review suggests potential strategies to address these limitations. The development of effective protocols for the accurate identification and quantification of MPs in real-world samples is of paramount importance. This review further highlights the accumulation of microplastics in various edible species, such as crabs, pelagic fish, finfish, shellfish, American oysters, and mussels, shedding light on the extreme implications of MPs on our food chain.

Comprehensive Understanding of Self-Propelled Janus Pt/Fe2O3 Micromotor Dynamics: Impact of Size, Morphology, and Surface Structure

The increasing use of plastics has led to the accumulation of plastic waste in the oceans, resulting in significant global environmental challenges associated with microplastic pollution. Micromotors, capable of capturing and removing microplastics from aquatic systems, have emerged as a promising solution to addressing this problem. This research aims to analyze the factors affecting the speed of micromotors, including size, morphology, and surface structure, while elucidating the underlying mechanisms governing micromotor propulsion to develop efficient and ecofriendly micromotors. In this study, we systematically manipulate various parameters by modifying the synthesis method of hematite-based micromotors, subsequently comparing their propulsion speeds and uncovering the precise role of these parameters in determining the micromotor performance. Furthermore, we shed light on the intricate interplay between drag force and propulsive force, demonstrating how these forces vary under different H2O2 conditions. These findings provide valuable insights into the design of efficient micromotors tailored for dynamic aquatic environments.

Control strategies for microplastic pollution in groundwater

Groundwater is the primary source of water that occurs below the earth's surface. However, the advancement in technology and the increasing population, which lead to the discharge of contaminants such as microplastics (MPs), have an adverse impact on the quality of groundwater. MPs are ubiquitous pollutants that are widely found throughout the world. The maximum abundance of MPs is 4 items/L and 15.2 items/L in groundwater at the specific location of China and USA. Various factors can affect the migration of MPs from soil to groundwater. The occurrence of MPs in water causes serious health issues. Therefore, taking appropriate strategies to control MP contamination in groundwater is urgent and important. This review summarizes the current literature on the migration process of MPs from soil to groundwater along with possible methods for the remediation of MP-polluted groundwater. The main objective of the review is to summarize the technical parameters, process, mechanism, and characteristics of various remediation methods and to analyze strategies for controlling MP pollution in groundwater, providing a reference for future research. Possible control strategies for MP pollution in groundwater include two aspects: i) prevention of MPs from entering groundwater; ii) remediation of polluted groundwater with MPs (ectopic remediation and in-situ remediation). Formulating legislative measures, strengthening public awareness and producing more environment-friendly alternatives can be helpful to reduce the production of MPs from the source. Manage plastic waste reasonably is also a good strategy and the most important part of the management is recycling. The shortcomings of the current study and the direction of future research are also highlighted in the review.

Characterization and removal efficiencies of microplastics discharged from sewage treatment plants in Southeast Spain

Microplastics (MPs) are ubiquitous pollutants that can effectively harm different ecosystems. The information on the relative contribution of wastewater treatment plants (WWTPs) to the surrounding environment is important, in order to understand ecological health risks and implement measures to reduce their presence. This focus article presents a quantitative assessment on the relative concentration and types of MPs delivered from four WWTPs located at the Southeast of Spain. Samples from WWTPs were collected throughout a four-year period, comprising more than 1,200 L of analyzed wastewater and 3,215 microparticles isolated. Density extraction with 1.08 g/mL NaCl salt solution was systematically used as the main separation method, in a simple and reliable manner, and repeat extraction cycles did not play any significant impact on the study outcomes. The four WWTPs had removal efficiencies between 64.3% and 89.2% after primary, secondary, and tertiary treatment phases, without diurnal or daily variations. Advanced treatment methods displayed a lower removal rate for fibers than for particulate MPs. The abundance of MPs was always higher and with a lower mean size in wastewater samples collected in Autumn than for the rest of seasons. MPs dumped from WWTPs in large quantities into the environment are meant to be regarded as an important point source for aquatic and terrestrial environments.

Microplastics removal from aqueous environment by metal organic frameworks

This paper provides an overview of recent research performed on the applications of metal-organic frameworks (MOFs) for microplastics (MPs) removal from aqueous environments. MPs pollution has become a major environmental concern due to its negative impacts on aquatic ecosystems and human health. Therefore, developing effective and sustainable methods for removing them from aqueous environments is crucial. In recent years, MOFs have emerged as a promising solution for this purpose due to their unique properties such as high surface area, renewability, chemical stability, and versatility. Moreover, their specific properties such as their pore size and chemical composition can be tailored to enhance their efficiency in removing MPs. It has been shown that MOFs can effectively adsorb MPs from aqueous media in the range of 70-99.9%. Besides some high price concerns, the main drawback of using MOFs is their powder form which can pose challenges due to their instability. This can be addressed by supporting MOFs on other substrates such as aerogels or foams. Meanwhile, there is a need for more research to investigate the long-term stability of MOFs in aqueous environments and developing efficient regeneration methods for their repeated use.

An accessible method to standardize polyethylene microsphere (<100 μm) concentrations for zooplankton ingestion experiments

The ubiquity of microplastics has caused alarm as to the impact of these materials on aquatic life, leading to experimental studies to understand these effects. In zooplankton bioassays, microspheres (Ms) are often used as a proxy to represent aquatic microplastic contamination due to their homogeneity and small sizes (<100 μm). The present study proposes an accessible protocol that does not require highly specialized equipment for the creation of Ms stock solutions and environmentally realistic experimental concentrations and describes some common issues. Adult females of the calanoid copepod Centropages furcatus underwent treatments of two Ms sizes at experimental concentrations of 10 Ms/mL. They consumed on average 0.9 ± 2.6 Ms/mL of 45-53 μm Ms, and 2.4 ± 1.1 Ms/mL of 38-45 μm Ms. The results are not directly comparable with other studies due to the wide variety of methods used but successfully demonstrate the reproducibility of the proposed protocol.

Microplastic pollution in coastal areas of Colombia: Review

Microplastics are distributed in the environment and are considered emerging pollutants because they are not regulated by legislation. This article aims to know the current state of knowledge regarding microplastic pollution in coastal areas of Colombia. Therefore, a detailed search was carried out in databases such as Scopus, Google Scholar, and university repositories collecting scientific and academic information published between 2000 and March 2022. As a result of the review, the presence of microplastics in coastal areas of Colombia was identified, particularly in the water, sediments, and fish, thus evidencing the contamination in coastal ecosystems, where the Caribbean coast is the area with the highest amount of microplastics in sediments, especially Cartagena (249-1387 particles/m2) and Santa Marta (144-791 particles/m2). It was also found that of 302 species of fish, 7% contained microplastics in the Ciénaga Grande of Santa Marta. In the studies, on the other hand, it was observed that there is no standardized methodology; each researcher chooses a different approach according to the scientific literature. The studies showed that the most abundant microplastics were secondary microplastics, of which polypropylene and polyethylene are predominant due to their different applications in society. This review will serve as a baseline for future research on microplastics in coastal areas of Colombia and will identify the challenges and realities of the country in the face of these emerging pollutants.

Microplastics: a review of their impacts on different life forms and their removal methods

The pollution of microplastics (MPs) is a worldwide major concern, as they have become a major part of our food chain. MPs enter our ecosystem via different pathways, including anthropogenic activities and improper disposal of plastics. The aim of this article is to review the current scientific literature related to MPs and how they affect different life forms on earth. Briefly, MPs induced negative effects on humans are primarily linked with the oxidative stress and disruption in immunity. MPs not only affect the soil chemical and physical properties such as reduction in soil health and productivity but also impose harmful effects on soil microorganisms. Moreover, MP-induced plant growth reduction results from three complementary mechanisms: (i) reduction in root and shoot growth, (ii) reduction in photosynthesis accompanied by higher reactive oxygen species (ROS) production, and (iii) reduction in nutrient uptake via altered root growth. Given the negative effects of MPs on different life forms, it is important to remove or remediate them. We have discussed different MP removal methods including coagulation, membrane filtration technology, biochar, and biological degradation of MPs in soil and wastewater effluents. The use of ozone as ultrafiltration technique has also been shown as the most promising technique for MP removal. Finally, some future research recommendations are also put forward at the end to further enhance our understanding of the MPs induced negative effects on different life forms. The flowchart shows the interaction of MPs from water contaminated with MPs with different parts of the ecosystem and final interaction with human health.

Microplastics in food - a critical approach to definition, sample preparation, and characterisation

The ubiquity of microplastics (MPs) is a more and more frequently brought up topic. The fact that such particles are present in food raises particular concern. Information regarding the described contamination is incoherent and difficult to interpret. Problems appear already at the level of the definition of MPs. This paper will discuss ways of explaining the concept of MPs and methods used for its analysis. Isolation of characterised particles is usually performed using filtration, etching and/or density separation. Spectroscopic techniques are commonly applied for analysis, whereas visual evaluation of the particles is possible thanks to microscopic analysis. Basic information about the sample can be obtained by the combination of Fourier Transform Infrared spectroscopy or Raman spectroscopy and microscopy or using the thermal method combined with spectroscopy or chromatography. The unification of the research methodology will allow a credible assessment of the influence of this pollution coming from food on health.

A Complete Guide to Extraction Methods of Microplastics from Complex Environmental Matrices

Sustainable development is a big global challenge for the 21st century. In recent years, a class of emerging contaminants known as microplastics (MPs) has been identified as a significant pollutant with the potential to harm ecosystems. These small plastic particles have been found in every compartment of the planet, with aquatic habitats serving as the ultimate sink. The challenge to extract MPs from different environmental matrices is a tangible and imperative issue. One of the primary specialties of research in environmental chemistry is the development of simple, rapid, low-cost, sensitive, and selective analytical methods for the extraction and identification of MPs in the environment. The present review describes the developments in MP extraction methods from complex environmental matrices. All existing methodologies (new, old, and proof-of-concept) are discussed and evaluated for their potential usefulness to extract MPs from various biotic and abiotic matrices for the sake of progress and innovation. This study concludes by addressing the current challenges and outlining future research objectives aimed at combating MP pollution. Additionally, a set of recommendations is provided to assist researchers in selecting appropriate analytical techniques for obtaining accurate results. To facilitate this process, a proposed roadmap for MP extraction is presented, considering the specific environmental compartments under investigation. By following this roadmap, researchers can enhance their understanding of MP pollution and contribute to effective mitigation strategies.

The potential risks posed by micro-nanoplastics to the safety of disinfected drinking water

Micro-nanoplastics (M-NPs) have become an emerging critical issue in the environment because they migrate easily, can bioaccumulate with toxic effects, and are difficult to degrade. Unfortunately, the current technologies for removing or degrading M-NPs in drinking water are insufficient to eliminate them completely, and residual M-NPs in drinking water may pose a threat to human health by impairing human immunity and metabolism. In addition to their intrinsic toxic effects, M-NPs may be even more harmful after drinking water disinfection than before disinfection. Herein, this paper comprehensively summarizes the negative impacts of several commonly used disinfection processes (ozone, chlorine, and UV) on M-NPs. Moreover, the potential leaching of dissolved organics from M-NPs and the production of disinfection byproducts during the disinfection process are discussed in detail. Moreover, due to the diversity and complexity of M-NPs, their adverse effects may exceed those of conventional organics (e.g., antibiotics, pharmaceuticals, and algae) after the disinfection process. Finally, we propose enhanced conventional drinking water treatment processes (e.g., enhanced coagulation, air flotation, advanced adsorbents, and membrane technologies), detection of residual M-NPs, and biotoxicological assessment as promising and ecofriendly candidates to efficiently remove M-NPs and avoid the release of secondary hazards.

Surface change of microplastics in aquatic environment and the removal by froth flotation assisted with cationic and anionic surfactants

Microplastics (MPs) are increasingly released into the environment due to the widespread usage and improper management of plastics. Considerable research efforts have been devoted to the remediation of MPs. Froth flotation has been demonstrated as an effective method to remove MPs in water and sediment. However, there is a lack of knowledge on the regulation of the hydrophobicity/hydrophilicity of MPs surfaces. We found that exposure to the natural environment resulted in the increased hydrophilicity of MPs. The flotation efficiencies of polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), and polyethylene glycol terephthalate (PET) MPs decreased to zero after six months of natural incubation in rivers. According to various characterizations, the hydrophilization mechanism is mainly correlated with surface oxidation and the deposition of clay minerals. Inspired by surface wettability conversion, we applied surfactants (collectors) to enhance MPs hydrophobicity and flotation efficiency. Anionic sodium oleate (NaOL) and cationic dodecyl trimethyl ammonium chloride (DTAC) were used to regulate surface hydrophobicity. The effects of collector concentration, pH, conditioning time, and metal ions on MPs flotation were thoroughly elucidated. Characterizations and adsorption experiments were performed to describe the heterogeneous adsorption of surfactants on MPs surfaces. The interaction between surfactants and MPs was explained through density functional theory (DFT) simulations. The dispersion energy between hydrophobic hydrocarbon chains attracts collectors on the MPs surface, and the collector molecules wrap and laminate to MPs surfaces. Flotation using NaOL exhibited a higher removal efficiency, and NaOL was environmentally friendly. Subsequently, we investigated the activation of Ca²⁺, Fe³⁺, and Al³⁺ to further improve the collecting efficiency of NaOL. Under the optimized conditions, MPs in natural rivers could be removed by froth flotation. This study shows the great promise of froth flotation for the application of MPs removal.

Unaccounted Microplastics in the Outlet of Wastewater Treatment Plants—Challenges and Opportunities

Since the 1950s, plastic production has skyrocketed. Various environmental and human activities are leading to the formation and accumulation of microplastics (MPs) in aquatic and terrestrial ecosystems, causing detrimental effects on water, soil, plants, and living creatures. Wastewater treatment plants (WWTPs) are one of the primary MP management centers meant to check their entry into the natural systems. However, there are considerable limitations in effectively capturing, detecting, and characterizing these MPs in the inlet and outlet of WWTPs leading to “unaccounted MPs” that are eventually discharged into our ecosystems. In order to assess the holistic picture of the MPs’ distribution in the ecosystems, prevent the release of these omitted MPs into the environment, and formulate regulatory policies, it is vital to develop protocols that can be standardized across the globe to accurately detect and account for MPs in different sample types. This review will cover the details of current WWTP adoption procedures for MP management. Specifically, the following aspects are discussed: (i) several processes involved in the workflow of estimating MPs in the outlet of WWTPs; (ii) key limitations or challenges in each process that would increase the uncertainty in accurately estimating MPs; (iii) favorable recommendations that would lead to the standardization of protocols in the workflow and facilitate more accurate analysis of MPs; (iv) research opportunities to tackle the problem of ‘missing MPs’; and (v) future research directions for the efficient management of MPs. Considering the burgeoning research interest in the area of MPs, this work would help early scientists in understanding the current status in the field of MP analysis in the outlet of WWTPs.

Microplastics occurrence, detection and removal with emphasis on insect larvae gut microbiota

Microplastics have been identified in all living forms including human beings, the present need is to restrain its spread and devise measures to remediate microplastics from polluted ecosystems. In this regard, the present review emphasizes on the occurrence, sources detection and toxic effects of microplastics in various ecosystems. The removal of microplastics is prevalent by various physico-chemical and biological methods, although the removal efficiency by biological methods is low. It has been noted that the degradation of plastics by insect gut larvae is a well-known aspect, however, the underlying mechanism has not been completely identified. Studies conducted have shown the magnificent contribution of gut microbiota, which have been isolated and exploited for microplastic remediation. This review also focuses on this avenue, as it highlights the contribution of insect gut microbiota in microplastic degradation along with challenges faced and future prospects in this area.

Easy and accessible way to calibrate a fluorescence microscope and to create a microplastic identification key

We present here a technique for setting up detection limits on any fluorescent microscope in conjunction with the fluorophore Nile Red for microplastic identification. Our method also describes a rigorous morphology-specific identification key for microplastics to reduce subjectivity between researchers. The detection limits were established for nine common polymer types and five natural substrates which could result in false-positive signals when using Nile Red for microplastic identification. This method was then applied to real freshwater samples and identified particles were validated with micro-FTIR or Raman spectroscopy. This approach may reduce subjectivity in microplastic identification and counting and enhances transparency, repeatability and harmonization within microplastic research community.•Instructions for calibration of detection limits for microplastics on fluorescence microscope systems described•Microplastic identification key developed and tested to reduce false positive detection•Lower subjectivity for microplastic identification obtained using the detection limits & identification key.