Prevalence of microplastics in animal-based traditional medicinal materials: Widespread pollution in terrestrial environments

Exposure Pathways and Toxicity of Microplastics in Terrestrial Insects

The detrimental effects of plastics on aquatic organisms, including those of macroplastics, microplastics, and nanoplastics, have been well established. However, knowledge on the interaction between plastics and terrestrial insects is limited. To develop effective strategies for mitigating the impact of plastic pollution on terrestrial ecosystems, it is necessary to understand the toxicity effects and influencing factors of plastic ingestion by insects. An overview of current knowledge regarding plastic ingestion by terrestrial insects is provided in this Review, and the factors influencing this interaction are identified. The pathways through which insects interact with plastics, which can lead to plastic accumulation and microplastic transfer to higher trophic levels, are also discussed using an overview and a conceptual model. The diverse impacts of plastic exposure on insects are discussed, and the challenges in existing studies, such as a limited focus on certain plastic types, are identified. Further research on standardized methods for sampling and analysis is crucial for reliable research, and long-term monitoring is essential to assess plastic trends and ecological impacts in terrestrial ecosystems. The mechanisms underlying these effects need to be uncovered, and their potential long-term consequences for insect populations and ecosystems require evaluation.

Exposure of U.S. adults to microplastics from commonly-consumed proteins

We investigated microplastic (MP) contamination in 16 commonly-consumed protein products (seafoods, terrestrial meats, and plant-based proteins) purchased in the United States (U.S.) with different levels of processing (unprocessed, minimally-processed, and highly-processed), brands (1 - 4 per product type, depending on availability) and store types (conventional supermarket and grocer featuring mostly natural/organic products). Mean (±stdev) MP contamination per serving among the products was 74 ± 220 particles (ranging from 2 ± 2 particles in chicken breast to 370 ± 580 in breaded shrimp). Concentrations (MPs/g tissue) differed between processing levels, with highly-processed products containing significantly more MPs than minimally-processed products (p = 0.0049). There were no significant differences among the same product from different brands or store types. Integrating these results with protein consumption data from the American public, we estimate that the mean annual exposure of adults to MPs in these proteins is 11,000 ± 29,000 particles, with a maximum estimated exposure of 3.8 million MPs/year. These findings further inform estimations of human exposure to MPs, particularly from proteins which are important dietary staples in the U.S. Subsequent research should investigate additional drivers of MPs in the human diet, including other understudied food groups sourced from both within and outside the U.S.

The digestive system of a cricket pulverizes polyethylene microplastics down to the nanoplastic scale

Microplastics (MPs; <5 mm) are a growing concern and a poorly understood threat to biota. We used a generalist insect (a cricket; Gryllodes sigillatus) to examine whether individuals would ingest and physically degrade MPs in their food. We fed crickets a range of concentrations (0, 2.5, 5, and 10% w/w) of fluorescent polyethylene MPs mixed into a standard diet and dissected the gut regions to isolate the MPs within. Comparing plastic content and fragment size within gut regions, we sought to identify whether and where crickets can fragment ingested MP particles. Given the digestive tract morphology of this species, we expected that the crickets would both ingest and egest the MPs. We also predicted that the MPs would be fragmented into smaller pieces during this digestive process. We found that G. sigillatus egested much smaller pieces than they ingested, and this fragmentation occurs early in the digestive process of this insect. We found this for both sexes as well as across the range of concentrations of MPs. The degree of plastic breakdown relative to plastic feeding time suggests that the ability to fragment MPs is intrinsic and not altered by how much time crickets have spent eating the plastics. The amount of plastics found in each region of the gut in relation to feeding time also suggests that this size and shape of PE microplastic does not cause any physical blockage in the gut. This lack of evidence for blockage is likely due to plastic breakdown. We found a ∼1000-fold reduction in plastic size occurs during passage through the digestive system, yielding particles very near nanoplastics (NPs; <1 μm), and likely smaller, that are then excreted back into the environment. These findings suggest that generalist insects can act as agents of plastic transformation in their environment if/when encountering MPs.

Assessment of polystyrene nano plastics effect on human salivary α-amylase structural alteration: Insights from an in vitro and in silico study

The study found that the enzyme activity of human salivary α-amylase (α-AHS) was competitively inhibited by nanoplastic polystyrene (PS-NPs), with a half-inhibitory concentration (IC50) of 92 μg/mL, while the maximum reaction rate (Vmax) remained unchanged at 909 μg/mL•min. An increase in the concentration of PS-NPs led to a quenching of α-AHS fluorescence with a slight red shift, indicating a static mechanism. The binding constant (Ka) and quenching constant (Kq) were calculated to be 2.92 × 1011 M-1 and 1.078 × 1019 M-1• S-1 respectively, with a hill coefficient (n) close to one and an apparent binding equilibrium constant (KA) of 1.54 × 1011 M-1. Molecular docking results suggested that the interaction between α-AHS and PS-NPs involved π-anion interactions between the active site Asp197, Asp300 residues, and van der Waals force interactions affecting the Tyr, Trp, and other residues. Fourier transform infrared (FT-IR) and circular dichroism (CD) analyses revealed conformational changes in α-AHS, including a loss of secondary structure α-helix and β-sheet. The study concludes that the interaction between α-AHS and PS-NPs leads to structural and functional changes in α-AHS, potentially impacting human health. This research provides a foundation for further toxicological analysis of MPs/NPs in the human digestive system.

Microplastics in marine-derived traditional Chinese medicine, potential threat to patients

Microplastics (MPs) contamination is widely found in marine organisms. Marine traditional Chinese medicines (MTCM) are derived from marine organisms, but there are no relevant reports on detecting MPs in MTCM. This study selected samples of MTCM from two representative pharmaceutical companies, Brand F and Brand Z, including mother-of-pearl, stone cassia, seaweed, pumice, oyster, kombu, calcined Concha Arcae, cuttlebone, and clam shell to detect and analyze the presence of MPs. The abundance, type, color, size, and composition of MPs were investigated. Varying degrees of MPs contamination was present in all MTCM. The abundance of MPs in different MTCM ranged from 0.07 to 9.53 items/g. Their type, color, and size are similar, mainly fiber, transparent and size <2 mm. The composition of MPs is primarily made of cotton, cellulose and rayon. This study contributes to the first record of MPs in MTCM. Our results show that microplastic pollution is common in MTCM, which may cause potential risk to patients consuming MTCM.

Unveiling Fragmentation of Plastic Particles during Biodegradation of Polystyrene and Polyethylene Foams in Mealworms: Highly Sensitive Detection and Digestive Modeling Prediction

It remains unknown whether plastic-biodegrading macroinvertebrates generate microplastics (MPs) and nanoplastics (NPs) during the biodegradation of plastics. In this study, we utilized highly sensitive particle analyzers and pyrolyzer-gas chromatography mass spectrometry (Py-GCMS) to investigate the possibility of generating MPs and NPs in frass during the biodegradation of polystyrene (PS) and low-density polyethylene (LDPE) foams by mealworms (Tenebrio molitor larvae). We also developed a digestive biofragmentation model to predict and unveil the fragmentation process of ingested plastics. The mealworms removed 77.3% of ingested PS and 71.1% of ingested PE over a 6-week test period. Biodegradation of both polymers was verified by the increase in the δ13C signature of residual plastics, changes in molecular weights, and the formation of new oxidative functional groups. MPs accumulated in the frass due to biofragmentation, with residual PS and PE exhibiting the maximum percentage by number at 2.75 and 7.27 μm, respectively. Nevertheless, NPs were not detected using a laser light scattering sizer with a detection limit of 10 nm and Py-GCMS analysis. The digestive biofragmentation model predicted that the ingested PS and PE were progressively size-reduced and rapidly biodegraded, indicating the shorter half-life the smaller plastic particles have. This study allayed concerns regarding the accumulation of NPs by plastic-degrading mealworms and provided critical insights into the factors controlling MP and NP generation during macroinvertebrate-mediated plastic biodegradation.

The effects of polyethylene microplastics on the growth, reproduction, metabolic enzymes, and metabolomics of earthworms Eisenia fetida

The existing data regarding the effects of polyethylene (PE) microplastics (MPs) smaller than 5 mm in size on earthworms are insufficient to fully comprehend their toxicity. In this study, earthworms Eisenia fetida were exposed to artificially added PE at a concentration ranging from 0.05 to 20 g/kg soil (0.005%-2%) for 60 days to determine the concentration range causing negative effects on earthworms and to uncover the potential toxic mechanisms. The individual growth, reproduction, and metabolic enzyme activities, including phase I enzymes (cytochrome P450 [CYP] 1A2, 2B6, 2C9, and 3A4), and phase II metabolic enzymes (superoxide dismutase (SOD), catalase (CAT), and glutathione sulfotransferase (GST)), and metabolomics were measured. The observed variations in responses of multiple cross-scale endpoints indicated that individual indices are less responsive to PE MPs than metabolic enzymes or metabolomics. Despite the absence of significant alterations in growth inhibition based on body weight, PE MPs at concentrations equal to or exceeding 2.5 g/kg were found to exert a toxic effect on earthworms, which was evidenced by significant changes in metabolic enzyme activities (CYP1A2, 2B6, 2C9, and 3A4, SOD, CAT, and GST) and important small molecule metabolites screened based on metabolomics, likely due to the bioaccumulation of PE. The toxicity of PE MPs to earthworms is inferred to be associated with neurotoxicity, oxidative damage, decreased detoxification capacity, energy metabolism imbalance, and impaired amino acid and purine metabolism due to bioaccumulation. The findings of this study will enhance our understanding of the molecular toxicity mechanisms of PE MPs and contribute to a more accurate assessment of the ecological risks posed by PE MPs in soil.

Microplastics affect arsenic bioavailability by altering gut microbiota and metabolites in a mouse model

Microplastics exposure is a new human health crisis. Although progress in understanding health effects of microplastic exposure has been made, microplastic impacts on absorption of co-exposure toxic pollutants such as arsenic (As), i.e., oral bioavailability, remain unclear. Microplastic ingestion may interfere As biotransformation, gut microbiota, and/or gut metabolites, thereby affecting As oral bioavailability. Here, mice were exposed to arsenate (6 μg As g^-1) alone and in combination with polyethylene particles of 30 and 200 μm (PE-30 and PE-200 having surface area of 2.17 × 10³ and 3.23 × 10² cm² g^-1) in diet (2, 20, and 200 μg PE g^-1) to determine the influence of microplastic co-ingestion on arsenic (As) oral bioavailability. By determining the percentage of cumulative As consumption recovered in urine of mice, As oral bioavailability increased significantly (P < 0.05) from 72.0 ± 5.41% to 89.7 ± 6.33% with PE-30 at 200 μg PE g^-1 rather than with PE-200 at 2, 20, and 200 μg PE g^-1 (58.5 ± 19.0%, 72.3 ± 6.28%, and 69.2 ± 17.8%). Both PE-30 and PE-200 exerted limited effects on pre- and post-absorption As biotransformation in intestinal content, intestine tissue, feces, and urine. They affected gut microbiota dose-dependently, with lower exposure concentrations having more pronounced effects. Consistent with the PE-30-specific As oral bioavailability increase, PE exposure significantly up-regulated gut metabolite expression, and PE-30 exerted greater effects than PE-200, suggesting that gut metabolite changes may contribute to As oral bioavailability increase. This was supported by 1.58-4.07-fold higher As solubility in the presence of up-regulated metabolites (e.g., amino acid derivatives, organic acids, and pyrimidines and purines) in the intestinal tract assessed by an in vitro assay. Our results suggested that microplastic exposure especially smaller particles may exacerbate the oral bioavailability of As, providing a new angle to understand health effects of microplastics.

Migration of microplastics from plastic packaging into foods and its potential threats on human health

Microplastics from food packaging material have risen in number and dispersion in the aquatic system, the terrestrial environment, and the atmosphere in recent decades. Microplastics are of particular concern due to their long-term durability in the environment, their great potential for releasing plastic monomers and additives/chemicals, and their vector-capacity for adsorbing or collecting other pollutants. Consumption of foods containing migrating monomers can lead to accumulation in the body and the build-up of monomers in the body can trigger cancer. The book chapter focuses the commercial plastic food packaging materials and describes their release mechanisms of microplastics from packaging into foods. To prevent the potential risk of microplastics migrated into food products, the factors influencing microplastic to the food products, e.g., high temperatures, ultraviolet and bacteria, have been discussed. Additionally, as many evidences shows that the microplastic components are toxic and carcinogenic, the potential threats and negative effects on human health have also been highlighted. Moreover, future trends is summarized to reduce the microplastic migration by enhancing public awareness as well as improving waste management.

Biomonitoring of Airborne Microplastic Deposition in Semi-Natural and Rural Sites Using the Moss Hypnum cupressiforme

We show that the native moss Hypnum cupressiforme can be used as a biomonitor of atmospheric microplastics (MPs). The moss was collected in seven semi-natural and rural sites in Campania (southern Italy) and was analyzed for the presence of MPs, according to standard protocols. Moss samples from all sites accumulated MPs, with fibers representing the largest fraction of plastic debris. Higher numbers of MPs and longer fibers were recorded in moss samples from sites closer to urbanized areas, likely as the results of a continuous flux from sources. The MP size class distribution showed that small size classes characterized sites having a lower level of MP deposition and a high altitude above sea level.

Microplastics in human food chains: Food becoming a threat to health safety

While versatile application of plastics has generated huge benefits in our life, the 'plastic end-of-life' comes with downsides of emerging concern is plastic particles within all parts of environments. Plastics are highly resistant to degradation and sustain in the environment for a prolonged period resulting in easy access of microplastics into human food chain. Microplastic exposure to humans is caused by foods of both animal and plant origin, food additives, drinks, and plastic food packaging. Living organisms can accumulate microplastics in cells and tissues which results in threats of chronic biological effects and potential health hazards for humans including body gastrointestinal disorders, immunity, respiratory problem, cancer, infertility, and alteration in chromosomes. Because of the threat of microplastics on human health, it is essential to ensure food safety as well as control plastic use with strict regulation of proper management. This study aims to enlighten future research into the core component of microplastics, their exposure to human food, prevention to human food chain, and biological reactions in human body. Finally, it is recommended to consider the presence of microplastics in different foods, as most of the existing research mainly focused on sea foods. And it is important to study the mechanism of toxicity with pathways in the human body based on the different types, shapes, and sizes of plastic particles.

Review of research on migration, distribution, biological effects, and analytical methods of microfibers in the environment

Microplastics have been proven to be one of the critical environmental pollution issues. Moreover, microfibers, the most prominent form of microplastics in the environment, have likewise attracted the attention of various countries. With the increase in global population and industrialization, the production and use of fibers continue to increase yearly. As a result, a large number of microfibers are formed. If fiber products are not used or handled correctly, it will cause direct/indirect severe microfiber environmental pollution. Microfibers will be further broken into smaller fiber fragments when they enter the natural environment. Presently, researchers have conducted extensive research in the identification of microfibers, laying the foundation for further resourcefulness research. This work used bibliometric analysis to review the microfiber contamination researches systematically. First, the primary sources of microfibers and the influencing factors are analyzed. We aim to summarize the influence of the clothing fiber preparation and care processes on microfiber formation. Then, this work elaborated on the migration in/between water, atmosphere, and terrestrial environments. We also discussed the effects of microfiber on ecosystems. Finally, microfibers' current and foreseeable effective treatment, disposal, and resource utilization methods were explained. This paper will provide a structured reference for future microfiber research.

Impact of coronavirus pandemic litters on microfiber pollution-effect of personal protective equipment and disposable face masks

Coronavirus Pandemic is the current biggest challenge against humanity. Apart from the personal health issues and higher mortality by the coronavirus, recent research works have also reported the environmental impacts of the pandemic. The review aims to analyze the current status of face masks and personal protective equipment littering and subsequent environmental impact in terms of microplastic and microfiber pollution. Recent researches in this domain are collected from the leading databases with relevant keywords and critically analyzed. The review results report a multi-fold increment in the usage of personal protective equipment, particularly face masks after the pandemic. Mismanagement of these items leads them to reach the marine environment through a variety of transportation. The results show a significant amount of increment in plastic and pandemic-related littering after the pandemic. The systematic review shows that the use of synthetic fibers in disposable personal protective equipment and masks leads to release of  fibers that can add-on to microfiber pollution. The results are also true in the case of reusable masks as the repeated laundry and disinfection methods release a significantly higher amount of microfibers. Only very few studies have addressed the release of microfiber from the mask, and no studies have reported the impact of personal protective equipment. The worldwide mass adaptation and improper disposal of these materials increase the seriousness of the problem multiple folds. These findings suggest the immediate requirement of critical analysis of the pandemic-related littering and microfiber release characteristics. The research also urges the need for the implementation of an environmental management plan as a mitigation strategy around the globe.

Ecotoxicological effects of micro- and nanoplastics on terrestrial food web from plants to human beings

Micro- and nanoplastics (MNPs) are present in almost all environmental compartments. Terrestrial soils are major environmental reservoirs for MNPs, but the ecotoxicological effects of MNPs on terrestrial biota remain relatively understudied. In this review, we collated findings of previous research on the uptake and impact of MNPs in terrestrial organisms, including flora, fauna, and human beings. Terrestrial plants can take up MNPs via the roots or leaves and translocate them to other parts. MNPs have been detected in the gastrointestinal tracts or feces of many terrestrial animals, including some high trophic-level predators, indicating the incidence of direct ingestion or trophic transfer of MNPs. The presence of MNPs in food items and human feces combines to verify human intake of MNPs via the dietary pathway. Exposure to MNPs can cause diverse effects on terrestrial organisms, including alterations in growth performance, oxidative stress, metabolic disturbance, cytotoxicity, genotoxicity, and mortality. The biological internalization and impact of MNPs are influenced by the physicochemical properties of MNPs (e.g., particle size, polymer type, surface chemistry, and exposure concentrations) and the physiology of the species. MNPs can also affect the bioavailability of co-occurring intrinsic or extrinsic contaminants to terrestrial biota, but their specific role is under dispute. Finally, we underlined the current research gaps and proposed several priorities for future studies.

Female mosquito-a potential vector for transporting plastic residues to humans

With the prodigious use of plastics in the industrial sector and daily life, plastic has become one of the fastest-growing sources of pollution in the aquatic environment. Therefore, ingestion of micro/nanoplastics (MP/NPs) by aquatic organisms is inevitable. But the knowledge on the definite effect, ontogenetic transfer, and translocation of NPs remains incipient. Thus, this study examines the abundance of MPs in mosquito larvae collected from the sewage pit. Additionally, this study demonstrates the MPs-mediated biochemical alterations and effects on development of mosquito, and then ontogenetic transfer and translocation of NPs in Aedes aegypti. Totally 1241 MPs belonging to polyethylene, polycarbonate, polypropylene, polystyrene, polyvinyl chloride and nylon with sizes ranging from 0.5 μm to 80 μm in diameter were isolated from the mosquito larvae. Indeed all the four stages of mosquito larvae feed on NPs and subsequently transfer them to non-feeding pupa and then to flying adult mosquitoes, further to the offspring. However, the NPs exposure and accumulation did not affect the survival of mosquitoes, but altered the biochemical constituents, thereby delaying the development of mosquitoes. Notably the female mosquitoes that emerged from the NPs treatment group showed increased blood-feeding activity and increased starvation resistance capacity. The puzzling accumulation of NPs/residues in different organs, especially in the salivary gland signifies that female mosquitoes could potentially inject polymer residues into humans and animals. At the outset, these observations emphasize that the mosquitoes act as a vector of NPs in the aqueous environment and transport them to terrestrial animals.

Recent developments in microbial degradation of polypropylene: Integrated approaches towards a sustainable environment

Fossil-fuel-based plastics have many enticing properties, but their production has resulted in significant environmental issues that require immediate attention. Despite the fact that these polymers are manmade, some bacteria can degrade and metabolise them, suggesting that biotechnologies based on the principle of plastic biodegradation could be beneficial. Among different types of plastics, polypropylene (PP), either having low or high density, is one of the most consumed plastics (18.85%). Their debasement under natural conditions is somewhat tricky. Still, their debasement under natural conditions is rather difficult slightly. However, different scientists have still made efforts by employing other microbes such as bacteria, fungi, and guts bacteria of larvae of insects to bio-deteriorate the PP plastic. Pre-irradiation techniques (ultraviolet and gamma irradiations), compatibilizers, and bio-additives (natural fibers, starch, and polylactic acid) have been found to impact percent bio-deterioration of different PP derivatives stronglythe various. The fungal and bacterial study showed that PP macro/microplastic might serve as an energy source and sole carbon during bio-degradation. Generally, gravimetric method or physical characterization techniques such as FTIR, XRD, SEM, etc., are utilized to affirm the bio-degradation of PP plastics-based materials. However, these techniques are not enough to warrant the bio-deterioration of PP. In this regard, a new technique approach that measures the amount of carbon dioxide emitted during bacterial or fungus degradation has also been discussed. In addition, further exploration is needed on novel isolates from plastisphere environments, sub-atomic strategies to describe plastic-debasing microorganisms and improve enzymatic action strategies, and omics-based innovations to speed up plastic waste bio-deterioration.

Electrochemical-Based Extraction, Separation, and Purification of Coumarin Compounds from Trifolium chinensis

In order to deal with the problems of the unstable transformation process and volatile palatability of coumarin compounds in C. chinensis, a method for the extraction, separation, and purification of coumarins in Chinese medicinal materials based on electrochemistry was prepared. First, an electrochemical distance-independent localization mechanism is used to determine node locations and routing mechanisms, and an extraction method is designed to achieve automatic and accurate real-time collection, aggregation, and transmission of ever-growing data. Environmental information for C. chinensis is collected. On the basis of this method, according to the chemical properties of coumarin and the extraction rate of coumarin as an index, the two-phase solvent extraction method and macroporous adsorption resin method were used to separate and purify it, and the best separation was determined. The purification process achieves efficient purification of coumarin. The experimental results show that the retention rate of coumarin by ethyl acetate is 34.5–56.8% higher than that of the other three extractants. When the optimal process determined in this study is adopted, the coumarin adsorption rate is greater than 98% and the recovery rate is greater than 85%. The purity of samples with 50% coumarin content can be increased to more than 97%, which verifies the correctness and advancement of the separation and purification process in this study.

Complex Bilateral Interactions Determine the Fate of Polystyrene Micro- and Nanoplastics and Soil Protists: Implications from a Soil Amoeba

Nano- and microplastics have become a serious global concern, threatening our living environments. Previous studies have shown that many organisms, including bacteria, animals, and plants, can be affected by microplastics. However, little is known about one ecologically important group of soil organisms, the protists. In this study, we investigated how polystyrene micro- and nanoplastics interacted with a soil amoeba Dictyostelium discoideum. The results showed that environmental concentrations of nano- and microplastics could negatively affect the soil amoeba's fitness and development. D. discoideum ingested both nano- and microplastics through phagocytosis but packed and excreted them during slug migration, which also promoted their biodegradation. Fourier transform infrared spectroscopy analyses revealed the formation of new oxygen-containing functional groups and the sign of possible oxidation of polystyrene. Also, nano- and microplastic exposure disrupted the nutrient and energy metabolisms of D. discoideum and affected the expression of key genes (e.g., cf45-1, dcsA, aprA, dymB, and gefB) related to morphogenesis and phagocytosis. In conclusion, our results show that nano- and microplastics have complex bilateral interactions with the soil amoeba, affecting each other's fate in the soil environment. This study provides new insights into how soil protists interact with nano- and microplastics in the soil ecosystem.

Size/shape-dependent migration of microplastics in agricultural soil under simulative and natural rainfall

Agricultural soil is a sink of microplastics (MPs) in the environment. MPs in topsoil can be transferred deeply or into surrounding water by rainfall. However, little is known about rainfall-induced migration pattern of different MPs in agricultural soil. In this study, soil leaching experiments of 21 d were performed on Nile red-stained size-different polyethylene terephthalate (PET) particles, and shape-different polyethylene (PE) MPs under simulated or natural rainfall. Results showed that simulated rainfall of 5-25 mm/d caused intensity-dependent migration of MPs in horizontal and vertical directions. Maximum migration depth of MP particles arrived up to 4-7 cm. Rise of soil slopes could significantly increase horizontal mobility of MPs. Comparatively, natural rainfall of similar intensity caused relatively high mobility of MPs. Moreover, under both simulative and natural rainfall, mobility of MPs presented size/shape-different characteristics. Comparatively, small-size MPs (especially <1 mm) showed relatively high mobility in horizontal or vertical direction, and had high-frequency presence in runoff water. Of four MPs' shapes, fiber and film had relatively high mobility in comparison to particles. These results indicate that rainfall can cause size/shape-dependent migration of MPs in agricultural soil. It suggests size/shape-different environment fate of MPs, and provides a reference for MP control.

Microplastics and Their Impact on Reproduction—Can we Learn From the C. elegans Model?

Biologically active environmental pollutants have significant impact on ecosystems, wildlife, and human health. Microplastic (MP) and nanoplastic (NP) particles are pollutants that are present in the terrestrial and aquatic ecosystems at virtually every level of the food chain. Moreover, recently, airborne microplastic particles have been shown to reach and potentially damage respiratory systems. Microplastics and nanoplastics have been shown to cause increased oxidative stress, inflammation, altered metabolism leading to cellular damage, which ultimately affects tissue and organismal homeostasis in numerous animal species and human cells. However, the full impact of these plastic particles on living organisms is not completely understood. The ability of MPs/NPs to carry contaminants, toxic chemicals, pesticides, and bioactive compounds, such as endocrine disrupting chemicals, present an additional risk to animal and human health. This review will discusses the current knowledge on pathways by which microplastic and nanoplastic particles impact reproduction and reproductive behaviors from the level of the whole organism down to plastics-induced cellular defects, while also identifying gaps in current knowledge regarding mechanisms of action. Furthermore, we suggest that the nematode Caenorhabditis elegans provides an advantageous high-throughput model system for determining the effect of plastic particles on animal reproduction, using reproductive behavioral end points and cellular readouts.

Air conditioner filters become sinks and sources of indoor microplastics fibers

Indoor airborne microplastics fibers (MPFs) are emerging contaminants of growing concern. Nowadays, air conditioners (ACs) are widely used in indoor environments. However, little is known about their impact on the distribution of indoor MPFs. In this study, we first disclosed the prevalence of MPF contamination in filters for indoor split ACs used in living rooms, dormitories, and offices. The average density of microfibers was 1.47-21.4 × 10² items/cm², and a total 27.7-35.0% of fibers were MPFs. Of these fibers, the majority were polyester (45.3%), rayon (27.8%), and cellophane (20.1%). We further tracked the long-term accumulation of MPFs on AC filters in three types of rooms, and demonstrated that dormitories showed relatively heavy accumulation especially after running for 35-42 days. Furthermore, we found that simulative AC filters which had been lined with PET MPFs could effectively release those MPFs into indoor air, propelling them away from the ACs at varying distances. Statistical analysis showed that the estimated daily intake of MPFs (5-5000 μm length) from AC filters would increase gradually with their usage, with the intake volume reaching up to 11.2 ± 2.2-44.0 ± 8.9 items/kg-BW/day by the 70th day, although this number varied among people of different ages. Altogether, these findings suggest that AC filters can act as both a sink and a source of microplastics fibers. Therefore, AC filters should be evaluated not only for their substantial impact on the distribution of indoor airborne MPFs, but also for their role in the prevalence of the related health risks.

Microplastics and Nanoplastics: Emerging Contaminants in Food

As current concerns about food safety issues around the world are still relatively serious, more and more food safety issues have become the focus of people's attention. What's more serious is that environmental pollution and changes in human lifestyles have also led to the emergence of contaminants in food, microplastics (MPs) and nanoplastics (NPs) being typical representatives. MPs and NPs (M/NPs) in food are gradually becoming recognized by regulatory authorities and the public. Most published reviews on M/NPs have been focused on the environmental ecosystems. In those papers, it is only sporadically mentioned that M/NPs can also appear in food. As far as we know, there has not been a systematic review of the pollution and existing status of M/NPs in food. This Review focuses on the harmfulness of M/NPs, the ways in which M/NPs contaminate food, the residual amount of M/NPs in food, and the current analysis and detection methods for M/NPs in food. Current analysis and detection methods have problems such as being time-consuming, involving cumbersome operation, and giving poor accuracy. In the future, it will be necessary to increase the research on methods for efficient and sensitive separation and detection of M/NPs in food. Finally, it is hoped that this Review will arouse more people's awareness of and attention to the seriousness of M/NPs in food.

Methods for separating microplastics from complex solid matrices: Comparative analysis

Microplastics (MPs) are widely found in complex solid matrices such as soil, sediments and sludge. The separation procedure is crucial for effective analysis of MPs, but existing methods varied among studies. Here, we systematically summarize and compare separation methods including density, oil, electrostatic, magnetic, and solvent extraction separation. Density separation is the most commonly used approach, but time-consuming and discharging hazardous materials dependent on extraction solutions. In contrast, oil, electrostatic, magnetic separation and solvent extraction separation are emerging approaches with advantages of low-cost, quick, or environmentally-friendly, but with high request of instruments. Despite variation among these approaches, the separation efficiency is closely related to characteristics of MPs including polymer types, sizes and shapes. The treatment of digestion and fluorescence staining can facilitate the detection of MPs. This analysis suggests that further optimization and improvement of existing approaches can facilitate the development of new separation technology for assaying MPs in complex environmental matrices.

An innovative evaluation method based on polymer mass detection to evaluate the contribution of microfibers from laundry process to municipal wastewater

Clothes washing releases numerous microfibers, including microplastic fibers (MPFs). Although MPFs in laundry wastewater are an important source of microplastics (MPs) in wastewater treatment plants (WWTPs), credible quantitative assessments of their contributions remain limited. Polyester fiber is the most important textile fiber. Its component, polyethylene terephthalate (PET) polymer, can be quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The release of MPFs from polyester clothes through washing was quantified via simulation experiments, and the MPFs in two WWTPs were measured by microscopic counting and LC-MS/MS. Direct comparison of the abundances of PET MPFs in laundry wastewater and WWTP influents led to an undervalued contribution rate of 9%-11% of the PET MPFs in laundry wastewater to those in WWTP influents. However, comparison of the mass of PET MPFs in laundry wastewater and WWTPs influents revealed that the PET MPFs from laundry contributed approximately 50% of those in the WWTPs. The latter was confirmed by comparing the number of polyester fibers released during clothes washing to the calculated number of "model MPFs" in WWTPs according to the PET mass concentration. Based on the PET concentration, the annual discharge of PET MPs from WWTPs to the water environment could also be estimated.

Biodegradation of polypropylene by yellow mealworms (Tenebrio molitor) and superworms (Zophobas atratus) via gut-microbe-dependent depolymerization

Polypropylene (PP), a fossil-based polyolefin plastics widely used worldwide, is non-hydrolyzable and resistant to biodegradation as a major source of plastic pollutants in environment. This study focused on feasibility of PP biodegradation in the larvae of two species of darkling beetles (Coleoptera: Tenebrionidae) i.e., yellow mealworms (Tenebrio molitor) and superworms (Zophobas atratus) using PP foam with number-, weight-, and size-average molecular weights (M_n, M_w, and M_z) of 109.8, 356.2, and 765.0 kDa, respectively. The tests were conducted in duplicates with respective larvae (300 T. molitor and 200 Z. atratus each incubator) at 25 °C and 65% humidity for over a 35-day period. The larvae of T. molitor and Z. atratus fed with PP foam as sole diet consumed PP at 1.0 ± 0.4 and 3.1 ± 0.4 mg 100 larvae^-1 days^-1, respectively; when fed the PP foam plus wheat bran, the consumption rates were enhanced by 68.11% and 39.70%, respectively. Gel permeation chromatography analyses of the frass of T. molitor and Z. atratus larvae fed PP only indicated that M_w was decreased by 20.4 ± 0.8% and 9.0 ± 0.4%; M_n was increased by 12.1 ± 0.4% and 61.5 ± 2.5%; M_z was decreased by 33.8 ± 1.5% and 32.0 ± 1.1%, indicating limited extent depolymerization. Oxidation and biodegradation of PP was confirmed through analysis of the residual PP in frass. Depression of gut microbes with the antibiotic gentamicin inhibited PP depolymerization in both T. molitor and Z. atratus larvae. High throughput 16S rRNA sequencing revealed that Citrobacter sp. and Enterobacter sp. were associated with PP diets in the gut microbiome of Z. atratus larvae while Kluyvera was predominant in the T. molitor larvae. The results indicated that PP can be biodegraded in both T. molitor and Z. atratus larvae via gut microbe-dependent depolymerization with diversified microbiomes.

Environmental fate, ecotoxicity biomarkers, and potential health effects of micro- and nano-scale plastic contamination

In recent decades, the quantity of plastic waste products has increased tremendously. As plastic wastes are released into the environment, they exert harmful effects on biota and human health. In this work, a comprehensive review is offered to describe the physical and chemical characteristics of microplastics and nanoplastics in relation to their fate, microbial ecology, transport, and ecotoxic behavior. Present discussion is expanded further to cover the biochemical, physiological, and molecular mechanisms controlling the environmental fate, ecotoxicity, and human health hazards of micro- and nanoplastics. The risks of their exposure to microbes, plants, animals, and human health are also reviewed with special emphasis. Finally, a direction for future interdisciplinary research in materials and polymer science is also discussed to help control the pollution caused by micro- and nanoplastics.

Biodegradation and disintegration of expanded polystyrene by land snails Achatina fulica

Despite increasing evidence of widespread plastic pollution in soil, it remains largely unknown about the fate of plastic influenced by soil animals. In this study, ingestion and biodegradation capability of expanded polystyrene (PS) foam was investigated in a globally distributed soil invertebrate, Achatina fulica. After 4-week exposure, 18.5 ± 2.9 mg polystyrene was ingested per snail, and egested microplastics (1.343 ± 0.625 mm) in feces with significant mass loss of mean 30.7%. Gel permeation chromatography analysis indicated a significant increase in weight-average molecular weight (M_w) and number-average molecular weight (M_n) of feces-residual PS, indicating limited extent depolymerization. Fourier transform infrared spectroscopy and proton nuclear magnetic resonance confirmed the formation of functional groups of oxidized intermediates. Suppression of gut microbes with oxytetracycline did not affect the depolymerization, indicating the independence of gut microbes. High-throughput sequencing analysis revealed significant shifts in the gut microbiome after ingestion of PS, with an increase of family Enterobacteriaceae, Sphingobacteriaceae, and Aeromonadaceae, suggesting that gut microorganisms were associated with PS biodegradation. These findings suggest that plastic litter can be disintegrated into microplastics and partially biodegraded by A. fulica, which highlights the significance of soil animals for the fate of plastic and its biodegradation in soil environments.

Evidence of small microplastics (<100 μm) ingestion by Pacific oysters (Crassostrea gigas): A novel method of extraction, purification, and analysis using Micro-FTIR

Microplastics (MPs) are present in fresh, brackish, or marine waters. Micro- and macroinvertebrates can mistake MPs or small microplastics (SMPs, <100 μm) to be food particles and easily ingest them according to the size of their mouthparts. SMPs may then block the passage of food through the intestinal tract (i.e. hepatopancreas), accumulate within the organism, and enter the food web. Pacific oysters (Crassostrea gigas) are allochthonous filter-feeding bivalve mollusks, which have been introduced in coastal seas around the world in both natural banks and farms. Considering their economic and ecological value, these bivalves have been chosen as a model to study the ingestion of SMPs. A novel method for the extraction and purification of SMPs in bivalves was developed. Quantification and simultaneous polymer identification of SMPs using Micro-FTIR (Fourier Transform Infrared Spectroscopy) were performed, with a limit of detection for the particle size of 5 μm.

Microplastics in Food: A Review on Analytical Methods and Challenges

Human exposure to microplastics contained in food has become a significant concern owing to the increasing accumulation of microplastics in the environment. In this paper, we summarize the presence of microplastics in food and the analytical methods used for isolation and identification of microplastics. Although a large number of studies on seafood such as fish and shellfish exist, estimating the overall human exposure to microplastics via food consumption is difficult owing to the lack of studies on other food items. Analytical methods still need to be optimized for appropriate recovery of microplastics in various food matrices, rendering a quantitative comparison of different studies challenging. In addition, microplastics could be added or removed from ingredients during processing or cooking. Thus, research on processed food is crucial to estimate the contribution of food to overall human microplastic consumption and to mitigate this exposure in the future.

Microplastics and nanoplastics in global food webs: A bibliometric analysis (2009-2019)

This paper presents the research landscape on microplastics and nanoplastics (M/NPs) in global food webs based on a bibliometric analysis of 330 publications published in 2009-2019 extracted from Web of Science. The publications increased tremendously since 2013. Marine Pollution Bulletin is one of the top productive journals for this topic. The publication landscape related to M/NPs in global food webs, as interdisciplinary research, is highly dependent on the funding availability. The high productivities of England, China, USA and European countries are attributed to the funding from the agencies at regional or national levels. Keyword analysis reveals the shift of research hotspots from investigations on M/NPs absorbed by various organisms in the ecosystems to studies on the trophic transfer of M/NPs and sorbed contaminants in the food webs and their associated adverse impacts. Funding agencies play important roles in leading the future development of this topic.

Synthesis of arylidene hydrazinylpyrido[2,3-d]pyrimidin-4-ones as potent anti-microbial agents

Combination of arylidene hydrazinyl moiety with pyrido[2,3-d]pyrimidin-4-one skeleton in compounds 7‒26 results in the output of unprecedented anti-microbial agents. Arylidene hydrazinyl based on Pyrido[2,3-d]pyrimidin-4-one analoges 7‒26 prepared by the treatment of [2,3-d]pyrimidin-4-ones 6a,b with various aromatic aldehydes. The antimicrobial action for recently synthesized compounds was considered towards gram positive bacterial species (Staphylococcus aurous ATCC- 47077; Bacillus cereus ATCC-12228), gram negative bacterial species (Escherichia coli ATCC-25922; Salmonella typhi ATCC-15566) and Candida albicans ATCC-10231 as fungal strains. The antimicrobial action expanded by expanding the electron donating group in position 2 and 5 for Pyrido[2,3-d]pyrimidin-4-one core. Derivatives 13, 14, 15, 16 and 12; individually appeared hopeful anti-microbial action towards all strains utilized with inhibition zone higher than that of standard reference drug with lowest MIC.