Environmental prevalence, fate, impacts, and mitigation of microplastics-a critical review on present understanding and future research scope

Microplastics in the soil-water-food nexus: Inclusive insight into global research findings

Nuisance imposed by biotic and abiotic stressors on diverse agroecosystems remains an area of focus for the scientific fraternity. However, emerging contaminants such as microplastics (MP) have imposed additional dimension (alone or in combinations with other stressors) in agroecosystems and keep escalating the challenges to achieve sustainability. MP are recognized as persistent anthropogenic contaminants, fetch global attention due to their unique chemical features that keeps themselves unresponsive to the decaying process. This review has been theorized to assess the current research trends (along with possible gap areas), widespread use of MP, enhancement of the harshness of heavy metals (HMs), complex interactions with physico-chemical constituents of arable soil, accumulation in the edible parts of field crops, dairy products, and other sources to penetrate the food web. So far, the available review articles are oriented to a certain aspect of MP and lack a totality when considered from in soil-water-food perspective. In short, a comprehensive perspective of the adverse effects of MP on human health has been assessed. Moreover, an agro-techno-socio-health prospective-oriented critical assessment of policies and remedial measures linked with MP has provided an extra edge over other similar articles in influential future courses of research.

Unveiling the Tiny Invaders: A deep dive into microplastics in shrimp - Occurrence, detection and unraveling the ripple effects

Aquaculture is a rapidly expanding food sector worldwide; it is the farming of fish, shellfish, and other marine organisms. Microplastics (MPs) are small pieces of plastic with a diameter of less than 5 mm that end up in the marine environment. MPs are fragments of large plastics that take years to degrade but can frustrate into small pieces, and some commercially available MPs are used in the production of toothpaste, cosmetics, and aircraft. MPs are emerging contaminants; they are ingested by marine species. These MPs have effects on marine species such as growth retardation and particle translocation to other parts of the body. Recently, MPs accumulation has been observed in shrimps, as well as in a wide range of other scientific reports. So, in this study, we review the presence, accumulation, and causes of MPs in shrimp. These plastics can trophic transfer to other organisms, changes in plastic count, effects on the marine environment, and impacts of MPs on human health were also discussed. It also improves our understanding of the importance of efficient plastic waste management in the ocean, as well as the impact of MPs on marine biota and human health.

Estimated exposure to microplastics through national and local brands of bottled water in Central India

Microplastics (MPs) are ubiquitous pollutants that affect various environmental matrices, including air, water, soil, food, and beverages. In India, there is limited research on microplastics in bottled drinking water, which is a significant route of MP exposure to the human body. To date, the data on the occurrence of MPs in national and local bottled water brands have not been studied and compared. Therefore, the current study focuses on the contamination of MPs in bottled water from different national and local brands procured from the market of Nagpur, India. The MPs were observed in all the analyzed samples. It was observed that the local bottled water showed higher MP contamination compared to national bottled water, with MP concentrations of 212 ± 100 MPs/L and 72 ± 36 MPs/L, respectively. The MPs were identified and characterized using microscopic and attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) analysis, revealing that the dominant MP particles were fragments (71%), followed by fibers (23%), and others (6%). Among the observed particles, 50% of particles were black colored, followed by transparent (16%), red (13%), orange (8%), green (3%), blue (5%), and yellow (5%). The predominant polymer types were polyethylene (PE) and polyethylene terephthalate (PET). Overall, the pollution load indices suggested a moderate level of contamination in bottled water samples. Furthermore, the estimated annual human exposure to MPs was calculated as 5186 ± 3751 p/kg-bw/year for children and 1482 ± 1072 p/kg-bw/year for adults, making it a significant route of human exposure to MPs.

Assessment of microplastic abundance and impact on recreational beaches along the western Algerian coastline

Microplastics (MPs) have attracted global attention due to their ubiquity and potential impact on the environment. However, MPs are poorly documented along the Algerian coast. To address this data gap, this study investigated the presence of MPs on three recreational beaches in western Algeria (Stidia, Sablettes and Mersat El Hadjaj). The mean MP abundance for the three beaches was estimated at 55.47 ± 48.01 items/m2. Characterization of MPs shape revealed that fragments (79.81 %) were dominant, followed by pellets (10.58 %), filaments (5.57 %), and foam (3.85 %). An assessment of the Microplastic Pollution Index, the Pellet Pollution Index, and the Coefficient of Microplastic Impact, revealed the presence of very low to moderate levels of MPs on the beaches. This presence was associated with minimal beach pollution and moderate overall impact. The sector analysis approach results confirm that there are two different magnitudes of MPs presence that can negatively impact on the environmental quality of the studied beaches.

Micro and nano plastics in food: A review on the strategies for identification, isolation, and mitigation through photocatalysis, and health risk assessment

Over the past few years, it has become increasingly evident that microplastic pollutant heavily contaminates water sources, posing a potential threat to both human and wildlife. These plastic pollutants do not get degraded efficiently by natural processes and the existing traditional treatment methods are incapable of fully eradicating them. In this regard, degradation of microplastic contaminants through photocatalytic methods has emerged as a powerful technique. Unfortunately, only a limited number of investigations have been reported in the field of photocatalytic degradation of microplastics. This comprehensive assessment focuses on the detailed analysis of the latest cutting edge engineered technologies aimed at efficiently separating, identifying microplastic contaminants present in food samples and degrading them through photocatalysis. Moreover, detailed information on various instrumental techniques that can be adopted to analyze the isolated micro sized plastic particles has been discussed. The assessment and degradation of these micro contaminants through photocatalytic methods is still in juvenile stage and there are lot of rooms to be explored. The need for profound contemplation on methods to degrade them through photocatalytic approaches as well as their possible health risks to humans motivated us to bring out this review.

A comprehensive review of micro- and nano-plastics in the atmosphere: Occurrence, fate, toxicity, and strategies for risk reduction

Micro- and nano-plastics (MNPs) have received considerable attention over the past 10 years due to their environmental prevalence and potential toxic effects. With the increase in global plastic production and disposal, MNP pollution has become a topic of emerging concern. In this review, we describe MNPs in the atmospheric environment, and potential toxicological effects of exposure to MNPs. Studies have reported the occurrence of MNPs in outdoor and indoor air at concentrations ranging from 0.0065 items m-3 to 1583 items m-3. Findings have identified plastic fragments, fibers, and films in sizes predominantly <1000 μm with polyamide (PA), polyester (PES), polyethylene terephthalate (PET), polypropylene (PP), rayon, polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), polyacrylonitrile (PAN), and ethyl vinyl acetate (EVA) as the major compounds. Exposure through indoor air and dust is an important pathway for humans. Airborne MNPs pose health risks to plants, animals, and humans. Atmospheric MNPs can enter organism bodies via inhalation and subsequent deposition in the lungs, which triggers inflammation and other adverse health effects. MNPs could be eliminated through source reduction, policy/regulation, environmental awareness and education, biodegradable materials, bioremediation, and efficient air-filtration systems. To achieve a sustainable society, it is crucial to implement effective strategies for reducing the usage of single-use plastics (SUPs). Further, governments play a pivotal role in addressing the pressing issue of MNPs pollution and must establish viable solutions to tackle this significant challenge.

Review: Mitigation measures to reduce tire and road wear particles

The generation of tire wear is an inevitable outcome of the friction between the road and the tire which is necessary for the safe operation of vehicles on roadways. Tire wear particles form agglomerates with road surface material. These agglomerates are called tire and road wear particles (TRWP). Due to their persistence in the environmental compartments and their potentially harmful effects, research on preventative and end-of-pipe mitigation strategies for TRWP is essential. The major goal of this study is to summarize and assess the state of the art in science and technology of mitigation measures for TRWP as the basis for further research activities. Approximately 500 literature sources were found and analyzed in terms of the efficiency, maturity, implementation, and impact of the mitigation measures. Generally, technological and management mitigation measures to reduce the generation of TRWP are beneficial since they prevent TRWP from entering the environment. Once released into environmental compartments, their mobility and dispersion would increase, making removing the particles more challenging. Technological and management mitigation measures after the release of TRWP into the environment are mainly well established in industrialized countries. Street cleaning and wastewater technologies show good removal efficiencies for TRWP and microplastics. In any case, no individual measure can solely solve the TRWP issue, but a set of combined measures could potentially be more effective. The absence of fully-developed and standardized methods for tire abrasion testing and measuring TRWP in the environment makes it impossible to reliably compare the tire abrasion behavior of different tire types, determine thresholds, and control mitigation actions. Field tests and pilot studies are highly needed to demonstrate the effectiveness of the abatement measures under real conditions.

Interactive effects of polyethylene microplastics and cadmium on growth of Glycine max

The interaction of microplastics (MPs) and heavy metals (HMs) can lead to aggravation of detrimental effects in the plants, animals, and even human beings. Keeping this in view, the present study was designed to assess the combined toxic effects of polyethylene MPs (PE-MPs) and cadmium (Cd) on germination indices and seedling growth of soybean (Glycine max). Particle sizes of 13 and 6.5 μm and six treatments (control, Cd, 6.5 μm PE, 6.5 μm PE + Cd, 13 μm PE, and 13 μm PE + Cd) were set to simulate the effects of PE-MPs and Cd on the growth of soybean when used alone or in combined form. As compared to the control, 6.5 μm PE treatment showed significant effect on most of the germination indices, i.e., decrease in the germination index by 31%, 44% decrease in the vigor index, and 28% decrease in germination rate whereas mean germination time showed no significant differences. Treatment of smaller-size PE-MPs and Cd significantly inhibited both dry and fresh weights. All treatment groups resulted in significant effect on catalase, peroxidase, and superoxide dismutase activities of seedlings depicting adverse effects of interaction of PE-MPs and Cd. Our findings demonstrated the phyto-toxicity of PE-MPs and Cd in G. max, and it would lead to serious implications in human beings. Our study is important as it provides preliminary information regarding MP absorption and their accumulation in different levels of food chain. It can also form the basis for future research on single the combined effects of different types and sizes of MPs and heavy metals on the terrestrial plants.

Analyzing the impacts of cadmium alone and in co-existence with polypropylene microplastics on wheat growth

Heavy metals typically coexist with microplastics (MPs) in terrestrial ecosystems. Yet, little is known about how the co-existence of heavy metals and MPs affect crops. Therefore, this study aimed to evaluate the impact of cadmium (Cd; 40 mg/L) alone and its co-existence with polypropylene (PP)-MPs (50 and 100 µm) on seed germination, root and shoot growth, seedling dry weight (DW), and antioxidant enzyme activities of wheat. The study demonstrated that the germination rate of wheat did not vary significantly across treatment groups. Yet, the inhibitory impact on wheat seed germination was strengthened under the co-existence of Cd and PP-MPs, as the effect of a single treatment on seed germination was non-significant. The germination index and mean germination time of wheat seeds were not affected by single or combined toxicity of Cd and PP-MPs. In contrast, Cd and PP-MPs showed synergistic effects on germination energy. Wheat root and shoot length were impeded by Cd alone and in combination with PP-MPs treatments. The DW of wheat seedlings showed significant change across treatment groups until the third day, but on the seventh day, marginal differences were observed. For example, on third day, the DW of the Cd treatment group increased by 6.9% compared to CK, whereas the DW of the 100 µm PP-MPs+Cd treatment group decreased by 8.4% compared to CK. The co-occurrence of Cd and PP-MPs indicated that 50 μm PP-MPs+Cd had an antagonistic impact on wheat seedling growth, whereas 100 μm PP-MPs+Cd had a synergistic impact due to the larger size of PP-MPs. The antioxidant enzyme system of wheat seeds and seedlings increased under single Cd pollution, while the activities of superoxide dismutase, catalase, and peroxidase were decreased under combined pollution. Our study found that Cd adversely affects wheat germination and growth, while the co-existence of Cd and PP-MPs have antagonistic and synergistic effects depending on the size of the PP-MPs.

Environmental impacts of microplastic and role of plastisphere microbes in the biodegradation and upcycling of microplastic

Increasing usage of plastic has led to the deposition of plastic in the environment which later become microplastic, a pollutant of global concern. These polymeric particles affect the ecosystem bestowing toxicity and impede the biogeochemical cycles. Besides, microplastic particles have been known for their role in aggravating the effect of various other environmental pollutants including organic pollutants and heavy metals. These microplastic surfaces are often colonized by the microbial communities also known as "plastisphere microbes" forming biofilms. These microbes include cyanobacteria like Nostoc, Scytonema, etc., and diatoms like Navicula, Cyclotella, etc. Which become the primary colonizer. In addition to the autotrophic microbes, Gammaproteobacteria and Alphaproteobacteria dominate the plastisphere microbial community. These biofilm-forming microbes can efficiently degrade the microplastic in the environment by secreting various catabolic enzymes such as lipase, esterase, hydroxylase, etc. Besides, these microbes have shown great potential for the bioconversion of microplastic to polyhydroxyalkanoates (PHA), an energy efficient and sustainable alternative to the petroleum based plastics. Thus, these microbes can be used for the creation of a circular economy using waste to wealth strategy. This review provides a deeper insight into the distribution, transportation, transformation, and biodegradation of microplastic in the ecosystem. The formation of plastisphere by the biofilm-forming microbes has been described in the article. In addition, the microbial metabolic pathways and genetic regulations involved in the biodegradation have been discussed in detail. The article suggests the microbial bioremediation and upcycling of microplastic along with various other strategies for effectively mitigate the microplastic pollution.

Review of microplastics in the indoor environment: Distribution, human exposure and potential health impacts

The emergence of microplastics (MPs) pollution as a global environmental concern has attracted significant attention in the last decade. The majority of the human population spends most of their time indoors, leading to increased exposure to MPs contamination through various sources such as settled dust, air, drinking water and food. Although research on indoor MPs has intensified significantly in recent years, comprehensive reviews on this topic remain limited. Therefore, this review comprehensively analyses the occurrence, distribution, human exposure, potential health impact and mitigation strategies of MPs in the indoor air environment. Specifically, we focus on the risks associated with finer MPs that can translocate into the circulatory system and other organs, emphasizing the need for continued research to develop effective strategies to mitigate the risks associated with MPs exposure. Our findings suggest that indoor MPs impose potential risk to human health, and strategies for mitigating exposure should be further explored.

Potential risk assessment and toxicological impacts of nano/micro-plastics on human health through food products

The problem of environmental pollution with plastic is becoming more and more acute every year. Due to the low rate of decomposition of plastic, its particles get into food and harm the human body. This chapter focuses on the potential risks and toxicological effects of both nano and microplastics on human health. The main places of distribution of various toxicants along with the food chain have been established. The effects of some examples of the main sources of micro/nanoplastics on the human body are also emphasised. The processes of entry and accumulation of micro/nanoplastics are described, and the mechanism of accumulation that occurs inside the body is briefly explained. Potential toxic effects reported from studies on various organisms are highlighted as well.

Emerging plastic litter variants: A perspective on the latest global developments

Plastic litter is one of key reasons of environmental concern due to its adverse effect on ecosystem and health. Exposure of plastic litter to anthropogenic and ecological conditions results in a variety of emerging litter variants that fluctuate in composition, mechanical, and chemical properties. Considering the properties of these plastic litter variants, it is anticipated that the transportation of foreign species or microbial pathogens together with these litter variants is most likely to affect the marine ecosystem. Moreover the plastic litter may enter the plastic cycle or marine biota and can spread across the ocean. Very recently several emerging plastic litter variants such as anthropoquinas, plasticrust, pyroplastic, plastitar, and plastiglomerate have been reported along the coastal areas across the oceans. The purpose of this perspective is to comprehend these emerging plastic litter variants, integrate the latest developments and highlight their adverse effects on the coastal ecosystem. Further, it details the make-up, place of origin, and management strategies for these plastic litter variants.

Airborne microplastics: Occurrence, sources, fate, risks and mitigation

This paper serves to enhance the current knowledge base of airborne microplastics which is significantly smaller than that of microplastics in marine, freshwater and terrestrial environments. It systematically presents the prevalence, sources, fate, risks and mitigations of airborne microplastics through the review of >140 scientific papers published mainly in the last 10 years. Unlike the extant review, it places an emphasis on the indoor microplastics, the risks of airborne microplastics on animals and plants and their mitigations. The outdoor microplastics are mostly generated by the wear and tear of tires, brake pads, waste incineration and industrial activities. They have been detected in many regions worldwide at concentrations ranging from 0.3 particles/m³ to 154,000 particles/L of air even in the Pyrenees Mountains and the Arctic. As for indoor microplastics, the reported concentrations range from 1 piece/m³ to 9900 pieces/m²/day, and are frequently higher than those of the outdoor microplastics. They come from the wear and tear of walls and ceilings, synthetic textiles and furniture finishings. Airborne microplastics could be suspended and resuspended, entrapped, settle under gravity as well as interact with chemicals, microorganisms and other microplastic particles. In the outdoors, they could also interact with sunlight and be carried by the wind over long distance. Airborne microplastics could adversely affect plants, animals and humans, leading to reduced photosynthetic rate, retarded growth, oxidative stress, inflammatory responses and increased cancer risks in humans. They could be mitigated indirectly through filters attached to air-conditioning system and directly through source reduction, regulation and biodegradable substitutes.

Exploration of Single and Co-Toxic Effects of Polypropylene Micro-Plastics and Cadmium on Rice (Oryza sativa L.)

The widespread application of micro-plastics (MP) and their release in the open environment has become a matter of worldwide concern. When interacting with contaminants such as heavy metals in the soil ecosystem, MPs can result in detrimental effects on the soil environment and plant growth and development. However, information based on the interaction between MPs and heavy metals and their effects on terrestrial plants is still limited. Keeping this in mind, the present study was conducted to explore the single and combined toxicity of polypropylene (PP) MPs (13 and 6.5 μm) and cadmium (Cd) on germination indices; root and stem growth; fresh and dry weight; and anti-oxidative enzyme activities of rice (Oryza sativa L.) seedlings. Our results indicated that a single application of PP MP and Cd on rice seedlings inhibited most of the germination indicators, while their co-occurrence (PP + Cd) showed a reduction in the overall toxicity to some extent. A single application of both the contaminants significantly inhibited root length, stem length, fresh weight and the activities of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) enzymes in rice seedling, while no significant effect on dry weight was observed. The combined toxicity of both PP and Cd revealed that 13 μm PP + Cd had an antagonistic effect on the growth of rice seedlings, while 6.5 μm PP + Cd showed a synergistic effect. The present study revealed that smaller PP MP particles (6.5 µm) prominently affected plant growth more as compared to larger particles (13 µm). Our work reported the combined effect of PP MP and Cd on the germination and growth of rice for the first time. This study can provide the basis for future research on the combined effects of different types and sizes of MPs and heavy metals on the terrestrial ecosystem.

Characterization and removal of microplastics in a sewage treatment plant from urban Nagpur, India

Sewage treatment plant (STP) acts as a potential source of microplastic contamination in the environment. The presence of microplastics in the sewage treatment plant is reported over the globe in varying concentrations. Hence, the current study is intended to evaluate the presence and abundance of microplastics occurring in sewage treatment plants in India. The samples were processed through digestion and density separation, followed by microscopic and polymer identification through Fourier transform infrared spectroscopy. Also, different wastewater parameters were studied to analyze their influence. High microplastic concentrations were detected in the influent (1860 ± 265 MPs/L), which reduced by > 90%, to around 148 ± 51 MPs/L in the effluent. The concentration of microplastics in sewage sludge was 830 MPs/kg. The prominent plastic types identified include low-density polyethylene, polypropylene, polyurethane, polyvinyl chloride, and rayon. The smaller particles prevail in the effluent, releasing around 30 billion particles per day to the environment. This suggests that the current STP is efficient in removing the majority of the particles, but considerations are needed to avoid the ecological risks associated.

Micro- and nanoplastic contamination in livestock production: Entry pathways, potential effects and analytical challenges

The abundant and widespread presence of particulate plastics in the environment is considered an area of increasing environmental, animal and human health concern. Despite the abundance and the potential to cause deleterious biological effects, studies related to the impact of micro and nanoplastics (MNPs) on livestock animals are limited. This review evaluates the sources and entry pathways of particulate plastics in all the types of livestock production systems. The potential health effects of MNPs on mouse models, ruminant animals and a few other livestock animals are discussed. Since evaluation of MNPs in almost all types of matrices in hindered by analytical challenges, this review also evaluates the commonly used methods, emerging techniques, and quality control/quality assurance (QC/QA) procedures. Plastic mulching, fragmentation of plastic wastes and stream water runoff have been identified as major routes of MNPs entry in grazing-based and mixed livestock production systems. Notwithstanding the controlled indoor environment and relatively efficient waste management, MNPs have been detected in industrial livestock systems. The bioaccumulation and biomagnification of chemical toxicants can exacerbate the adverse effects of MNPs on higher trophic level species. Although there are several methods for the analysis of MNPs, dearth of standardized methods, certified reference materials, MPs standards, and global database libraries are major impediments. The adverse effects of MNPs on the internal organs of different livestock animals have to be studied using large sample sizes and without raising ethical concerns. Importantly, investigations on the accurate quantification of MNPs and its adverse effects in various livestock animals using rapid, cost-effective and robust analytical methods are required.

A baseline study of meso and microplastic predominance in pristine beach sediment of the Indian tropical island ecosystem

The global presence and prevalence of microplastic have moved microplastic from an emerging pollutant to a persistent contaminant. Microplastic prevails in almost all spheres of the environment viz. terrestrial, marine and atmosphere the globe abundantly. The prevalence and toxic effects on marine organisms have been studied around the world but the studies are limited to the coastal regime of the Andaman and Nicobar Islands (ANI). This study aims to record microplastic prevalence on the tourist beaches of Port Blair, ANI. Three coastal stations namely Cove beach, Quarry beach and Wandoor beach were examined in detail in this regard. Microplastics in the form of lines, fragments, pellets, foams and fibres were found at the sampled sites. Wandoor beach recorded the highest microplastic particles ranging from 105-475 particles kg^-1 of sediment with the mean value of 249.82 ± 105.78 particles kg^-1. Quarry beach near the municipal waste dumpsite showed the lowest of 72.5-222.5 particles kg^-1 with a mean value of 135.625 ± 62.83 particles kg^-1. The polymeric forms found were High-density polyethylene (HDPE), polystyrene (PS), polypropylene (PP) and polyethylene terephthalate (PET). This study revealed microplastic input from municipal dump waste near the beach. Fourier Transform Infrared spectroscopy (FTIR) revealed the presence of a new type of polymer namely plasta zinc in the beach sediment, which possibly could be a nanoplastic. Its presence reveals the biological enzymatic degradation of microplastic occurring in the marine environment. Further investigations are required to determine the factors influencing the prevalence of microplastic, its toxic effects on marine habitat and microplastic degradation mechanisms in the marine habitat.

Waste Management in Qatar: A Systematic Literature Review and Recommendations for System Strengthening

Billions of tons of waste are generated annually, with the amount of waste rapidly increasing and its management expected to worsen. Qatar is a small and wealthy country in the Arabian Peninsula that is undergoing enormous economic and urban development. This study presents the results of a systematic literature review on waste management in Qatar and offers recommendations for system strengthening based on an analysis of the available evidence. The PRISMA guidelines were followed to review literature from the ProQuest and SCOPUS platforms, from which 82 unique publications were analyzed according to ten themes. The results draw upon diverse disciplinary and research focus areas related to waste management, ranging from the generation of value-added products from wastes to the role of religion in waste management awareness. The main recommendations emerging from the available evidence include the need for a holistic approach to address increasing waste generation, which must include diverse stakeholders such as government entities, researchers, and broad community representation for decision making as well as raising awareness for behavior change. Additionally, the main waste types, including construction, food, plastic, and electronic wastes, require specific attention since the cause of generation and type of management varies accordingly. The rise of interest in improving waste management, in particular to work toward meeting the targets of the Qatar National Vision and the National Development Strategy should bring about positive outcomes for strengthening waste management systems.

Microplastics pollution in sediments of Moroccan urban beaches: The Taghazout coast as a case study

This work describes the spatiotemporal analysis of microplastics (MPs) pollution in sediments collected on a high urbanized beach located in Taghazout coast, central Atlantic part of Morocco. The study area is mainly composed of moderately well-sorted fine sands with an average density of MPs that ranged between 915 MPs/kg in 2018 and 1448 MPs/kg in 2019. The most polluted sites were in the south part of Taghazout coast, close to facilities of where beachgoers are often found. Microplastic Pollution Index (MPPI), Microplastic Impact Coefficient (CMPI), Agglomerative Hierarchical Clustering (AHC), and Multidimensional Scaling (MDS) revealed spatiotemporal variation of MPs pollution. Thus, the principal component analysis (PCA) showed a low correlation between the sediment characteristics (i.e., grain size, sorting, skewness) and MPs densities. Overall, the outputs of this baseline recommend implementing plastic management strategies to eliminate or at least minimize the collateral effects generated by MPs pollution in sediments of urbanized beaches.

Sources and fate of atmospheric microplastics revealed from inverse and dispersion modelling: From global emissions to deposition

We combine observations from Western USA and inverse modelling to constrain global atmospheric emissions of microplastics (MPs) and microfibers (MFs). The latter are used further to model their global atmospheric dynamics. Global annual MP emissions were calculated as 9.6 ± 3.6 Tg and MF emissions as 6.5 ± 2.9 Tg. Global average monthly MP concentrations were 47 ng m^-3 and 33 ng m^-3 for MFs, at maximum. The largest deposition of agricultural MPs occurred close to the world's largest agricultural regions. Road MPs mostly deposited in the East Coast of USA, Central Europe, and Southeastern Asia; MPs resuspended with mineral dust near Sahara and Middle East. Only 1.8% of the emitted mass of oceanic MPs was transferred to land, and 1.4% of land MPs to ocean; the rest were deposited in the same environment. Previous studies reported that 0.74-1.9 Tg y^-1 of land-based atmospheric MPs/MFs (< 5 mm) are transported to the ocean, while riverine transport is between 3.3 and 14 Tg y^-1. We calculate that 0.418 ± 0.201 Tg y^-1 MPs/MFs (size up to 250 and 2500 µm) were transported from the land to ocean (large particles were ignored). Model validation against observations showed that particle removal must be urgently updated in global models.

The Intestinal Barrier—Shielding the Body from Nano- and Microparticles in Our Diet

Nano- and microparticles are an implicit part of the human diet. They are unknowingly ingested with our food that contains them as additives or pollutants. However, their impact on human health is not yet understood and controversially discussed. The intestinal epithelial barrier shields our body against exogenous influences, such as commensal bacteria, pathogens, and body-foreign particles and, therefore, protects our body integrity. Breakdown of the intestinal epithelial barrier and aberrant immune responses are key events in the pathogenesis of inflammatory bowel disease (IBD). Epithelial lesions might enable systemic translocation of nano- and microparticles into the system, eventually triggering an excessive immune response. Thus, IBD patients could be particularly vulnerable to adverse health effects caused by the ingestion of synthetic particles with food. The food-additive titanium dioxide (TiO2) serves as a coloring agent in food products and is omnipresent in the Western diet. TiO2 nanoparticles exacerbate intestinal inflammation by activation of innate and adaptive immune response. Because of serious safety concerns, the use of TiO2 as a food additive was recently banned from food production within the European Union. Due to environmental pollution, plastic has entered the human food chain, and plastic microparticles have been evidenced in the drinking water and comestible goods. The impact of plastic ingestion and its resulting consequences on human health is currently the subject of intense research. Focusing on TiO2 and plastic particles in the human diet and their impact on epithelial integrity, gut homeostasis, and intestinal inflammation, this review is addressing contemporary hot topics which are currently attracting a lot of public attention.

Microplastics pollution along the central Atlantic coastline of Morocco

This baseline study describes the microplastic (MPs) problem on seven beaches located on Agadir, central Atlantic coast of Morocco. Microplastics abundances (densities) ranged from 7680 MPs/kg to 34,200 MPs/kg above other world beaches. The following shapes were found: fibers, fragments, films, and pellets. Fibers were the dominant typology with a 73%. Polyethylene (PE) was the predominant polymer in all beaches with an average percentage of 59%, followed by Polypropylene (PP - 18%), Polystyrene (PS - 9%), Polyvinyl chloride (PVC - 8%), and Ethylene-vinyl acetate (EVA - 6%). Microplastics abundances presented in this work suggest continuous inputs of plastics of all sizes and types. Also, all observed shapes highlight a combination of sources (primary and secondary). Central Atlantic Moroccan beaches are currently affected by extreme values of MPs that demand urgent interventions to restore environmental quality.

Phytotoxic Effects of Polyethylene Microplastics on the Growth of Food Crops Soybean (Glycine max) and Mung Bean (Vigna radiata)

Accumulation of micro-plastics (MPs) in the environment has resulted in various ecological and health concerns. Nowadays, however, studies are mainly focused on toxicity of MPs on aquatic organisms, but only a few studies assess the toxic effects of micro-plastics on terrestrial plants, especially edible agricultural crops. The present study was aimed to investigate the adverse effects of polyethylene (PE) microplastics on the germination of two common food crops of China, i.e., soybean (Glycine max) and mung bean (Vigna radiata). Both the crops were treated with polyethylene microplastics (PE-MPs) of two sizes (6.5 μm and 13 μm) with six different concentrations (0, 10, 50, 100, 200, and 500 mg/L). Parameters studied were (i) seed vigor (e.g., germination energy, germination index, vigor index, mean germination speed, germination rate); (ii) morphology (e.g., root length, shoot length) and (iii) dry weight. It was found that the phyto-toxicity of PE-MPs to soybean (Glycine max) was greater than that of mung bean (Vigna radiata). On the 3rd day, the dry weight of soybean was inhibited at different concentrations as compared to the control and the inhibition showed decline with the increase in the concentration of PE-MPs. After the 7th day, the root length of soybean was inhibited by PE-MPs of 13 μm size, and the inhibition degree was positively correlated with the concentration, whereas the root length of mung bean was increased, and the promotion degree was positively correlated with the concentration. Present study indicated the necessity to explore the hazardous effects of different sizes of PE-MPs on the growth and germination process of agricultural crops. Additionally, our results can provide theoretical basis and data support for further investigation on the toxicity of PE-MPs to soybean and mung bean.

Microplastics in the Environment: Intake through the Food Web, Human Exposure and Toxicological Effects

Recently, studies on microplastics (MPs) have increased rapidly due to the growing awareness of the potential health risks related to their occurrence. The first part of this review is devoted to MP occurrence, distribution, and quantification. MPs can be transferred from the environment to humans mainly through inhalation, secondly from ingestion, and, to a lesser extent, through dermal contact. As regards food web contamination, we discuss the microplastic presence not only in the most investigated sources, such as seafood, drinking water, and salts, but also in other foods such as honey, sugar, milk, fruit, and meat (chickens, cows, and pigs). All literature data suggest not-negligible human exposure to MPs through the above-mentioned routes. Consequently, several research efforts have been devoted to assessing potential human health risks. Initially, toxicological studies were conducted with aquatic organisms and then with experimental mammal animal models and human cell cultures. In the latter case, toxicological effects were observed at high concentrations of MPs (polystyrene is the most common MP benchmark) for a short time. Further studies must be performed to assess the real consequences of MP contamination at low concentrations and prolonged exposure.

Ocean plastics: environmental implications and potential routes for mitigation - a perspective

This review provides a current summary of the major sources and distribution of ocean plastic contamination, their potential environmental effects, and prospects towards the mitigation of plastic pollution. A characterization between micro and macro plastics has been established, along with a comprehensive discussion of the most common plastic waste sources that end up in aquatic environments within these categories. Distribution of these sources stems mainly from improper waste management, road runoff, and wastewater pathways, along with potential routes of prevention. The environmental impact of ocean plastics is not yet fully understood, and as such, current research on the potential adverse health effects and impact on marine habitats has been discussed. With increasing environmental damage and economic losses estimated at $US 1.5 trillion, the challenge of ocean plastics needs to be at the forefront of political and societal discussions. Efforts to increase the feasibility of collected ocean plastics through value-added commercial products and development of an international supply chain has been explored. An integrative, global approach towards addressing the growing ocean plastic problem has been presented.