Microplastic fibres from synthetic textiles: Environmental degradation and additive chemical content

Variation of Young's modulus suggested the main active sites for four different aging plastics at an early age time

Precisely determining which bonds are more sensitive when plastic aging occurs is critical to better understand the mechanisms of toxic release and microplastics formation. However, the relationship between chemical bonds with the active aging sites changes and the aging behavior of plastics at an early age is still unclear. Herein, the mechanical behavior of four polymers with different substituents was characterized by the high-resolution AFM. Young's modulus (YM) changes suggested that the cleavage of C-Cl bonds in PVC, C-H bonds in PE and PP, and C-F bonds in PTFE are the main active aging sites for plastic aging. The aging degree of the plastics followed the order of PVC > PP > PE > PTFE. Two aging periods exhibited different YM change behavior, the free radical and cross-linking resulted in a minor increase in YM during the initiation period. Numerous free radicals formed and cross-linking reaction happened, causing a significant increase in YM during the propagation period. Raman spectroscopy verified the formation of microplastics. This research develops promising strategies to quantitatively evaluate the aging degrees using AFM and establish the relationship between chemical bonds and mechanical behavior, which would provide new method to predict plastic pollution in actual environments.

Beyond the cradle - Amidst microplastics and the ongoing peril during pregnancy and neonatal stages: A holistic review

Advancements in research concerning the occurrence of microplastics (MPs) in human blood, sputum, urine, and breast milk samples have piqued the interest of the scientific community, prompting further investigation. MPs present in the placenta, amniotic fluid, and meconium raise concerns about interference with embryonic development, leading to preeclampsia, stillbirth, preterm birth, and spontaneous abortion. The challenges posed by MPs extend beyond pregnancy, affecting the digestive, reproductive, circulatory, immune, and central nervous systems. This has spurred scientists to examine the origins of MPs in distinct environmental layers, including air, water, and soil. These risks continue after birth, as neonates are continuously exposed to MPs through everyday items such as breast milk, cow milk and infant milk powder, as well as plastic-based products like feeding bottles and breast milk storage bags. It is the need of the hour to strike a balance amidst lifestyle changes, alternative choices to traditional plastic products, raising awareness about plastic-related health risks, and fostering collaboration between the scientific community and policymakers. This review aims to provide fresh insights into potential sources of MP pollution, with a specific focus on pregnancy and neonates. It is the first compilation of its kind so far that includes critical studies on recently reported discoveries.

Microplastics in water: Occurrence, fate and removal

A global study on tap water samples has found that up to 83% of these contained microplastic fibres. These findings raise concerns about their potential health risks. Ingested microplastic particles have already been associated with harmful effects in animals, which raise concerns about similar outcomes in humans. Microplastics are ubiquitous in the environment, commonly found disposed in landfills and waste sites. Within indoor environments, the common sources are synthetic textiles, plastic bottles, and packaging. From the various point sources, they are globally distributed through air and water and can enter humans through various pathways. The finding of microplastics in fresh snow in the Antarctic highlights just how widely they are dispersed. The behaviour and health risks from microplastic particles are strongly influenced by their physicochemical properties, which is why their surfaces are important. Surface interactions are also important in pollutant transport via adsorption onto the microplastic particles. Our review covers the latest findings in microplastics research including the latest statistics in their abundance, their occurrence and fate in the environment, the methods of reducing microplastics exposure and their removal. We conclude by proposing future research directions into more effective remediation methods including new technologies and sustainable green remediation methods that need to be explored to achieve success in microplastics removal from waters at large scale.

Drought induces moderate, diverse changes in the odour of grassland species

Plants react to drought stress with numerous changes including altered emissions of volatile organic compounds (VOC) from leaves, which provide protection against oxidative tissue damage and mediate numerous biotic interactions. Despite the share of grasslands in the terrestrial biosphere, their importance as carbon sinks and their contribution to global biodiversity, little is known about the influence of drought on VOC profiles of grassland species. Using coupled gas chromatography-mass spectrometry, we analysed the odorants emitted by 22 European grassland species exposed to an eight-week-lasting drought treatment (DT; 30% water holding capacity, WHC). We focused on the odorants emitted during the light phase from whole plant shoots in their vegetative stage. Emission rates were standardised to the dry weight of each shoot. Well-watered (WW) plants (70% WHC) served as control. Drought-induced significant changes included an increase in total emission rates of plant VOC in six and a decrease in three species. Diverging effects on the number of emitted VOC (chemical richness) or on the Shannon diversity of the VOC profiles were detected in 13 species. Biosynthetic pathways-targeted analyses revealed 13 species showing drought-induced higher emission rates of VOC from one, two, three, or four major biosynthetic pathways (lipoxygenase, shikimate, mevalonate and methylerythritol phosphate pathway), while six species exhibited reduced emission rates from one or two of these pathways. Similarity trees of odorant profiles and their drought-induced changes based on a biosynthetically informed distance metric did not match species phylogeny. However, a phylogenetic signal was detected for the amount of terpenoids released by the studied species under WW and DT conditions. A comparative analysis of emission rates of single compounds released by WW and DT plants revealed significant VOC profile dissimilarities in four species only. The moderate drought-induced changes in the odorant emissions of grassland species are discussed with respect to their impact on trophic interactions across the food web. (294 words).

Enzyme_Metal-Organic Framework Composites as Novel Approach for Microplastic Degradation

Plastic pollution is one of the main worldwide environmental concerns. Our lifestyle involves persistent plastic consumption, aggravating the low efficiency of wastewater treatment plants in its removal. Nano/microplastics are accumulated in living beings, pushing to identify new water remediation strategies to avoid their harmful effects. Enzymes (e. g., Candida rugosa-CrL) are known natural plastic degraders as catalysts in depolymerization reactions. However, their practical use is limited by their stability, recyclability, and economical concerns. Here, enzyme immobilization in metal-organic frameworks (CrL_MOFs) is originally presented as a new plastic degradation approach to achieve a boosted plastic decomposition in aqueous systems while allowing the catalyst cyclability. Bis-(hydroxyethyl)terephthalate (BHET) was selected as model substrate for decontamination experiments for being the main polyethylene terephthalate (PET) degradation product. Once in contaminated water, CrL_MOFs can eliminate BHET (37 %, 24 h), following two complementary mechanisms: enzymatic degradation (CrL action) and byproducts adsorption (MOF effect). As a proof-of-concept, the capacity of a selected CrL_MOF composite to eliminate the BHET degradation products and its reusability are also investigated. The potential of these systems is envisioned in terms of improving enzyme cyclability, reducing costs along with feasible co-adsorption of plastic byproducts and other harmful contaminants, to successfully remove them in a single step.

Nontarget screening analysis of organic compounds in river sediments: a case study in the Taipu River of the Yangtze River Delta Region in China

Sediments are the vital fate of organic compounds, and the recognition of organic compounds in sediments is constructive in providing comprehensive and long-term information. In this study, a three-step nontarget screening (NTS) analysis workflow using comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOFMS) revealed the extensive existence of organic compounds in the Taipu River sediment. Organic compounds (705) were detected and divided into four structure-related groups or eight use-related classes. In the Taipu River's mainstream, a significant difference was found in the composition profiles of the identified organic compounds among various sites, demonstrating the organic compounds were more abundant in the midstream and downstream than in the upstream. Meanwhile, the hydrodynamic force was recognized as a potential factor influencing organic compounds' occurrence. Based on multiple statistical analyses, the shipping and textile printing industries were considered the significant contributors to the identified organic compounds. Considering the principles of the priority substances and the current status of the substances, two traditional pollutants and ten emerging organic compounds were recognized as the priority organic compounds for the Taipu River. Conclusively, this study established a workflow for NTS analysis of sediment samples and demonstrated the necessity of NTS analysis to evaluate the impact of terrestrial emissions of organic compounds on the aquatic environment.

Liquidlike, Low-Friction Polymer Brushes for Microfibre Release Prevention from Textiles

During synthetic textile washing, rubbing between fibres or against the washing machine, exacerbated by the elevated temperature, initiates the release of millions of microplastic fibres into the environment. A general tribological strategy is reported that practically eliminates the release of microplastic fibres from laundered apparel. The two-layer fabric finishes combine low-friction, liquidlike polymer brushes with "molecular primers", that is, molecules that durably bond the low-friction layers to the surface of the polyester or nylon fabrics. It is shown that when the coefficient of friction is below a threshold of 0.25, microplastic fibre release is substantially reduced, by up to 96%. The fabric finishes can be water-wicking or water-repellent, and their comfort properties are retained after coating, indicating a tunable and practical strategy toward a sustainable textile industry and plastic-free oceans and marine foodstuffs.

First national reference of microplastic contamination of French soils

The recent emergence of studies on plastic contamination of terrestrial environments has revealed the presence of microplastics (MP) in a variety of soil types, from the most densely populated areas to the most remote ones. However, the concentrations and chemical natures of MP in soils vary between studies, and only a few ones have focused on this issue in France. The MICROSOF project aimed to establish the first national references for French soil contamination by microplastics. 33 soil samples randomly chosen on the French soil quality-monitoring network were analyzed. The study collected data on the abundance of microplastics in the [315-5000] μm range, their chemical nature and size, as well as mass abundance estimates and other relevant information. Results demonstrated that 76 % of the soil samples contained microplastics, in concentrations ranging from <6.7 to 80 MP.kg-1 (dry soil). Most samples from croplands, grasslands and vineyards and orchards were contaminated, whereas only one sample from forest contained MP, suggesting an increased risk of microplastic contamination in soils exposed to agricultural practices. The MP abundances are not statistically different from similar studies, indicating an intermediate level of contamination in French soils. Despite intervention reports and surveys, the sources remain unclear at this stage. For the first time, an overview of the state of soil contamination in France, as well as the potential risks is provided.

Exploring the hidden chemical landscape: Non-target and suspect screening analysis for investigating solid waste-associated environments

Solid waste is an inevitable consequence of urbanization. It can be safely managed in municipal landfills and processing plants for volume reduction or material reuse, including organic solid waste. However, solid waste can also be discarded in (un-)authorized dumping sites or inadvertently released into the environment. Legacy and emerging contaminants have the potential to leach from solid waste, making it a significant pathway to the environment. Non-target screening (NTS) and suspect screening analysis (SSA) have become helpful tools in environmental science for the simultaneous analysis of a wide range of chemical compounds. However, the application of these analytical approaches to environmental samples related to Raw or Processed Solid Waste (RPSW) has been largely neglected so far. This perspective review examines the potential and policy relevance of NTS and SSA applied to waste-related samples (liquid, gaseous and solid). It addresses the hurdles associated with the chemical safety of solid waste accumulation, processing, and reuse, and the need for landfill traceability, as well as effectiveness of leachate treatments. We reviewed the current applications of NTS and SSA to environmental samples of RPSW, as well as the potential adaptation of NTS and SSA techniques from related fields, such as oilfield and metabolomics, to the solid waste domain. Despite the ongoing technical challenges, this review highlights the significant potential for the implementation of NTS and SSA approaches in solid waste management and related scientific fields and provides support and guidance to the regulatory authorities.

Microplastics in Scylla Serrata: A baseline study from southwest India

Scylla serrata plays a crucial role in India's seafood exports yet there exists limited understanding on the occurrence of microplastics (MPs) in these crabs. In this baseline study, we examined the presence of microplastics in the digestive tracts of S. serrata collected from the Kota mangroves, southwestern coast of India. Our analysis revealed the presence of 264 MPs in all the samples with an average (± standard deviation) of 29.33 (±11.53) MPs/Individual. The most dominant categories were fibres (98.86 %) and fragments (1.14 %). Primarily 0.1-0.3 mm (50.90 %) and 0.3-1 mm (37.65 %) size range dominated. The predominant polymers were polypropylene (33.71 %), high-density polyethylene (31.44 %), and polyethylene terephthalate (17.80 %). Scanning electron microscopy revealed extensive weathering on the surface of the microplastics. Risk assessments indicated severe risks to S. serrata due to microplastic ingestion emphasizing the need to protect delicate ecosystems like mangroves and the biota within.

From cracks to secondary microplastics - surface characterization of polyethylene terephthalate (PET) during weathering

Secondary microplastics are a product of the fragmentation of plastic debris. Despite concerns regarding the omnipresence of microplastics in the environment, knowledge about the mechanics of their actual formation is still limited. Fragmentation is usually linked to weathering, which alters the properties of the plastic and allows fragmentation to occur. Therefore, in this study, polyethylene terephthalate (PET) samples were exposed to artificial UV light or a combination of UV light and water for a total of three months to simulate natural weathering. The samples included three forms of PET with different production histories: pellets, yarns, and films. The surface alterations to the samples during weathering were characterized using scanning electron microscopy and Raman spectroscopy. Results indicated that the three different types of PET developed markedly different surface defects and also exhibited signs of weathering within different time frames. Differences were also found between samples exposed only to UV and those exposed to UV and submerged in water. In water, the first surface changes were spotted within 30 days of initial submersion and later developed into an organized crack network. Upon the introduction of mild mechanical forces, pieces of the weathered surface started to delaminate. The fragments from films had an elongated shape with a median size of 16.1 × 2.1 × 1.8 μm, resembling a fibre. If the weathered surface of a film were to detach completely, it could create 1.4-7.9 million microplastic fragments/cm2. For pellets, this number would range between 0.4 and 2.2 million microplastics/cm2. In addition to particle formation by surface delamination, particles also emerged on the weathered surfaces of all studied samples, presenting another possible source of micro-sized particles during weathering. Overall, the results of this work show that the weathering of plastics and the formation of microplastics are heavily influenced not only by the weathering mechanism but also by the type and production history of the polymers.

Various additive release from microplastics and their toxicity in aquatic environments

Additives may be present in amounts higher than 50% within plastic objects. Additives in plastics can be gradually released from microplastics (MPs) into the aquatic environment during their aging and fragmentation because most of them do not chemically react with the polymers. Some are known to be hazardous substances, which can cause toxicity effects on organisms and pose ecological risks. In this paper, the application of functional additives in MPs and their leaching in the environment are first summarized followed by their release mechanisms including photooxidation, chemical oxidation, biochemical degradation, and physical abrasion. Important factors affecting the additive release from MPs are also reviewed. Generally, smaller particle size, light irradiation, high temperature, dissolved organic matter (DOM) existence and alkaline conditions can promote the release of chemicals from MPs. In addition, the release of additives is also influenced by the polymer's structure, electrolyte types, as well as salinity. These additives may transfer into the organisms after ingestion and disrupt various biological processes, leading to developmental malformations and toxicity in offspring. Nonetheless, challenges on the toxicity of chemicals in MPs remain hindering the risk assessment on human health from MPs in the environment. Future research is suggested to strengthen research on the leaching experiment in the actual environment, develop more techniques and analysis methods to identify leaching products, and evaluate the toxicity effects of additives from MPs based on more model organisms. The work gives a comprehensive overview of current process for MP additive release in natural waters, summarizes their toxicity effects on organisms, and provides recommendations for future research.

Photodegradation of biodegradable plastics in aquatic environments: Current understanding and challenges

Direct and indirect photolysis are important abiotic processes in aquatic environments through which plastics can be transformed physically and chemically. Transport of biodegradable plastics in water is influenced by vertical mixing and turbulent flow, which make biodegradable plastics remain susceptible to sunlight and photolysis despite their high density. In general, biodegradable plastics are composed of ester containing polymers (e.g., poly(butylene succinate), polyhydroxyalkanoate, and polylactic acid), whereas non-biodegradable plastics are composed of long chains of saturated aliphatic hydrocarbons in their backbones (e.g., polyethylene, polypropylene, and polystyrene). Based on the reviewed knowledge and discussion, we may hypothesize that 1) direct photolysis is more pronounced for non-biodegradation than for biodegradable plastics, 2) smaller plastics such as micro/nano-plastics are more prone to photodegradation and photo-transformation by direct and indirect photolysis, 3) the production rate of reactive oxygen species (ROS) on the surface of biodegradable plastics is higher than that of non-biodegradable plastics, 4) the photodegradation of biodegradable plastics may be promoted by ROS produced from biodegradable plastics themselves, and 5) the subsequent reactions of ROS are more active on biodegradable plastics than non-biodegradable plastics. Moreover, micro/nanoplastics derived from biodegradable plastics serve as more effective carriers of organic pollutants than those from non-biodegradable plastics and thus biodegradable plastics may not necessarily be more ecofriendly than non-biodegradable plastics. However, biodegradable plastics have been largely unexplored from the viewpoint of direct or indirect photolysis. Roles of reactive oxygen species originating from biodegradable plastics should be further explored for comprehensively understanding the photodegradation of biodegradable plastics.

Effect of oxygen-containing functional groups on the micromechanical behavior of biodegradable plastics and their formation of microplastics during aging

Biodegradable plastics (BPs) are more prone to generate harmful microplastics (MPs) in a short time, which have always been ignored. Oxygenated functional group formation is considered to be a key indicator for assessing microplastic formation, while it is difficult to characterize at a very early stage. The micromechanical properties of the aging plastic during the formation of the MPs are highly influenced by the evolution of oxygen-containing functional groups, however, their relationship has rarely been revealed. Herein, we compared changes in the physicochemical properties of BPs and non-degradable plastic bags during aging in artificial seawater, soil, and air. The results showed that the oxidation of plastics in the air was the most significant, with the most prominent oxidation in BPs. The accumulation of carbonyl groups leads to a significant increase in the micromechanical properties and surface brittleness of the plastic, further exacerbating the formation of MPs. It was also verified by the FTIR, 2D-COS, AFM, and Raman spectroscopy analyses. Furthermore, the increased adhesion and roughness caused by oxygen-containing functional groups suggest that the environmental risks of BPs cannot be ignored. Our findings suggest that the testing of micromechanical properties can predicate the formation of the MPs at an early stage.

The associations between high-levels of urine benzophenone-type UV filters (BPs) and changes in serum lipid concentrations

Little is known about the potential health impacts of benzophenone-type UV filters (BPs) exposure among the general population. In our study conducted in Wuxi, China, we investigated the associations between the concentrations of eight BP-derivatives and five target lipid molecules. We collected basic information, serum, and urine samples from 120 residents aged 9 to 80 in Wuxi. We determined BPs in urine samples and lipid levels in serum samples. Generalized linear models were used to evaluate the differences in ln-transformed serum target lipids levels (μg/L) with different urine BPs quartiles compared to the lowest quartile. Benzophenone-4 (BP-4) had the highest detection rate (95.0%) and geometric mean concentration (1.96 μg/L) among all the BP-derivatives in our study population. The exposure levels of BPs were generally higher in females than in males. Participants in the 9-17 and 18-50 age groups exhibited greater levels of exposure to BPs than those in the 51-80 age group. We observed statistically significant changes in LysoPC (18:0), LysoPE (18:0), ΣLPL, and ΣTL concentrations between the highest and lowest quartiles of BP-4. Similar changes were found in LysoPE (18:0) concentration between the highest and lowest quartiles of ΣBP-3 and ΣBPs. High urine BP concentrations were associated with variations in our target serum lipids involved in neurological and metabolic disorders, and posed a potential health risk. Future studies are warranted to further validate and elucidate our findings.

Research progress on occurrence characteristics and source analysis of microfibers in the marine environment

Synthetic microfiber pollution is a growing concern in the marine environment. However, critical issues associated with microfiber origins in marine environments have not been resolved. Herein, the potential sources of marine microfibers are systematically reviewed. The obtained results indicate that surface runoffs are primary contributors that transport land-based microfibers to oceans, and the breakdown of larger fiber plastic waste due to weathering processes is also a notable secondary source of marine microfibers. Additionally, there are three main approaches for marine microplastic source apportionment, namely, anthropogenic source classification, statistical analysis, and numerical simulations based on the Lagrangian particle tracking method. These methods establish the connections between characteristics, transport pathways and sources of microplastics, which provides new insights to further conduct microfiber source apportionment. This study helps to better understand sources analysis and transport pathways of microfibers into oceans and presents a scientific basis to further control microfiber pollution in marine environments.

Characteristics and potential human health risks of microplastics identified in typical clams from South Yellow Sea Mudflat

The ingestion of clams (Meretrix) with microplastics (MP) contamination could pose potential risk to human health. The characteristics and potential risks of MP identified in wild-clam and farm-clam from South Yellow Sea Mudflat were studied comprehensively in this paper. The results indicated that MP were identified in both wild-clam (3.4-21.3 items/individual, 2.11-10.65 items/g) and farm-clam (1.3-20.8 items/individual, 0.62-8.67 items/g) among 21 sampling sites along South Yellow Sea Mudflat. The MP abundance of clams from marine estuarine or coast ports were significantly higher than those from purely marine coast mudflat, implying that environmental habitats played an important role on MP characteristics. MP abundance were significantly and positively related to shell length, shell height, shell width and soft tissue wet weight by Pearson test, suggesting the bigger the shell, there existed more MP abundance. Among MP in wild-clams and farm-clams, fragment, fiber were most abundant MP shapes, most MP's sizes were lower than 0.25 mm, the predominant colors were black, red, blue and transparent, chlorinated polyethylene (CPE) was the major polymer. Additionally, estimated dietary intake (EDI) of MP for adults via consumption of wild-clam and farm-clam were 1123.33 ± 399.97 and 795.07 ± 326.72 items/kg/year, respectively, suggesting EDI values of wild-clams were higher than those of farm-clams, and MP intake via wild-clam consumption were more than that via farm-clam consumption. The polymer risk indexes (PRI) of MP in total tissue and digestive system for wild-clam were 1297.8 ± 92.15 (hazard level: IV ~ V), 1038 ± 69.55 (IV ~ V), respectively, while PRI of MP in total tissue and digestive system for farm-clam were 979.92 ± 75.45 (III ~ IV), 735 ± 47.78 (III ~ IV), respectively, implying that PRI and hazard level of MP from wild-clam were higher than those from farm-clam, and the potential risks would decrease greatly when digestive systems of clams are removed during ingestion.

Additives of plastics: Entry into the environment and potential risks to human and ecological health

A steep rise in global plastic production and significant discharge of plastic waste are expected in the near future. Plastics pose a threat to the ecosystem and human health through the generation of particulate plastics that act as carriers for other emerging contaminants, and the release of toxic chemical additives. Since plastic additives are not covalently bound, they can freely leach into the environment. Due to their occurrence in various environmental settings, the additives exert significant ecotoxicity. However, only 25% of plastic additives have been characterized for their potential ecological concern. Despite global market statistics highlighting the substantial environmental burden caused by the unrestricted production and use of plastic additives, information on their ecotoxicity remains incomplete. By focusing on the ecological impacts of plastic additives, the present review aims to provide detailed insights into the following aspects: (i) diversity and occurrence in the environment, (ii) leaching from plastic materials, (iii) trophic transfer, (iv) human exposure, (v) risks to ecosystem and human health, and (vi) legal guidelines and mitigation strategies. These insights are of immense value in restricting the use of toxic additives, searching for eco-friendly alternatives, and establishing or revising guidelines on plastic additives by global health and environmental agencies.

Releases of microplastics and chemicals from nonwoven polyester fabric-based polyurethane synthetic leather by photoaging

The nonwoven PET fabrics are chemically, mechanically and thermally treated fiber aggregate without weaving, knitting or braiding, which could be used as a base to make polyurethane (PU) synthetic leather through a series of processing. Our research systematically compared the photoaging behaviors of pure non-woven PET base fabric (NPET-P) and PU synthetic leather (nonwoven PET-base fabrics with PU coating, NPET-U), and their possibilities for microplastic fibers (MPFs) generation and chemical transformation in water. NPET-U was photoaged to a higher oxidation degree with higher O/C ratios and more distinct changes in chemical structures. The amount of MPFs released from NPET-U (1.98 × 107 g/fibers) was significantly lower than that from NPET-P (4.76 × 107 g/fibers) after 360 h light irradiation (p value <0.05) with a slower degradation rate and delayed MPFs release. The lengths and diameters of released MPFs from NPET-U varied within a smaller range than that from NPET-P exposed to UV light irradiation. Natural sunlight aging of fabrics for 365 days was found to be equivalent to approximately 85.3-127.2 h UV aging in the laboratory, which indicated the lab accelerated experiments was extraordinarily intense to simulate natural sunlight aging. Furthermore, abundant calcium and sulfur-contained chemicals were detected in original fabrics and the leachate of 360 h light-aged fabrics using the inductively coupled plasma optical emission spectrometer (ICP-OES). The organic components of the leachate were separated according to their molecular weight with the changes of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and the UV response over aging time. UV stimulation aggravated the role of plastic polymers as disinfection by-product (DBP) precursors. Nevertheless, although NPET-U could produce more nitrogen-contained chemicals, it had similar formation potentials of nitrogen-containing DBPs as NPET-P. The discussion lucubrated the potential risks of the production of MPFs and chemical release in the leachate with regard to combined plastic pollution.

The molecular level degradation state of drift plastics in the Sea of Japan coastline

Polyethylene (PE) and polyethylene terephthalate (PET) are among the most abundant plastics polluting the oceans. However, their environmental fate depends on how they have been weathered. Due to its unique geography, the Sea of Japan is a pollution hotspot where plastics accumulate. In this study, the structures of plastics, having drifted into the Sea of Japan coastline environment, were analyzed with a particular focus on examining polymer crystallization and carbonyl formation; two factors which influence microplastic formation and the adsorption of contaminants onto plastic surfaces. PE in the coastal environment did not show evidence of crystallization, although carbonyl formation did increase. By contrast, PET bottles were shown to not be uniform in structure, with unaged bottles being less crystalline in the neck component compared to the body. Because of this difference, in environmental PET bottles, it was the bottle neck that showed increases in crystallization and carbonyl group formation.

(Micro)Plastics Are Toxic Pollutants

Plastics, including microplastics, have generally been regarded as harmful to organisms because of their physical characteristics. There has recently been a call to understand and regard them as persistent, bioaccumulative, and toxic. This review elaborates on the reasons that microplastics in particular should be considered as "toxic pollutants". This view is supported by research demonstrating that they contain toxic chemicals within their structure and also adsorb additional chemicals, including polychlorinated biphenyls (PCBs), pesticides, metals, and polycyclic aromatic hydrocarbons (PAHs), from the environment. Furthermore, these chemicals can be released into tissues of animals that consume microplastics and can be responsible for the harmful effects observed on biological processes such as development, physiology, gene expression, and behavior. Leachates, weathering, and biofilm play important roles in the interactions between microplastics and biota. Global policy efforts by the United Nations Environmental Assembly via the international legally binding treaty to address global plastic pollution should consider the designation of harmful plastics (e.g., microplastics) with associated hazardous chemicals as toxic pollutants.

Exposure sources and pathways of micro- and nanoplastics in the environment, with emphasis on potential effects in humans: A systematic review

Microplastics (MPs) are emerging pollutants that are ubiquitous in the environment, and may be a potential threat to human health. This review describes the MP exposure sources and pathways through drinking water, food intake, and air inhalation. The unregulated discharge of MPs in water sources and the absence of required MP filter technology in water treatment plants are important routes of MP exposure through drinking water. The presence of MPs in food may lead to the accumulation of MPs in the body. Exposure to MPs can occur through airborne fallout and dust inhalation in both indoor and outdoor environments. This review summarizes the MP exposure sources and possible pathways in the human body, and illustrates that the intake of drinking water, food consumption, and air inhalation should be assessed in during routine activities. Integr Environ Assess Manag 2023;19:1422-1432. © 2023 SETAC.

Toxicity of polyvinyl chloride microplastics on Brassica rapa

Microplastics (MPs) can pose high risk to living organisms due to their very small sizes. This study selected polyvinyl chloride MPs (PVC-MPs) which experienced up to 1000 h UV light radiation to investigate the influence of PVC-MPs on Brassica rapa growth. The outcomes showed the presence of PVC-MPs inhibited the plants' growth. The stem length, root length, fresh weight and dry weight of plants exposed to PVC-MPs after 30 days reduced by 45.9%, 35.2%, 26.1% and 5.2%, respectively. The chlorophyll, soluble sugar, malondialdehyde (MDA) and catalase (CAT) concentrations for plants exposed to PVC-MPs after 30 days increased by 25.9%, 135.7%, 88.7% and 47.1% respectively. It was also observed that PVC-MPs blocked the plants' leaf stomata and even entered plants' bodies. This might lead to PVC-MPs movement within the plants and influence plants' growth. The transcriptomic analysis results indicated that exposure to PVC-MPs up-regulated metabolic pathway of plant hormone signal transduction of the plants and down-regulated pathway network of ribosome. However, the research outcomes also showed that the PVC-MPs' locations in soil (located at the upper layers or at lower layers) and the UV light radiation time did not exert significantly different influences on inhibiting plants' growth. This can be attributed to PVC-MPs' small sizes and not much decomposition under light radiation. These imply that longer light radiation time and different particle sizes should be included into future research in order to further explore photodegraded MPs' toxicity effects on plants.

Impact of treatment chemicals on the morphology and molecular structure of microfibers and microplastic films in wastewater

This study investigated the impact of commonly used treatment chemicals on the morphology and molecular structure of microfibers (MFs) and microplastic films (MPFs) to determine whether significant changes could occur during wastewater treatment. MFs and MPFs were exposed to sodium hypochlorite (NaOCl), hydrogen peroxide (H2O2), calcium hydroxide (Ca(OH)2, pH 11), sodium hydroxide (NaOH, pH11), and hydrochloric acid (HCl, pH 3) at typical doses and exposure times used at wastewater treatment plants. Scanning electron microscopy (SEM) analysis and attenuated total reflectance-Fourier-transform infrared (ATR-FTIR) were used to examine any morphological or chemical changes after the treatment. Morphological changes were observed in the form of cracks, and increased roughness was revealed in the SEM and 3-D surface images. The results showed that MFs were more resistant to surface degradation than MPFs. Moreover, intensity peaks of ATR-FTIR revealed some partial dislodgement of the bonds in both MFs and MPFs after chemical treatment, but the overall polymer structure remained intact. The changes that occur on the surface of MFs and MPFs during chemical treatment can impact their fate, removal, and transportation behavior both at the treatment plant and after discharge to the environment.

Approach to an answer to "How dangerous microplastics are to the human body": A systematic review of the quantification of MPs and simultaneously exposed chemicals

This review aims to facilitate future research on microplastics (MPs) in the environment using systematic and analytical protocols, ultimately contributing to assessment of the risk to human health due to continuous daily exposure to MPs. Despite extensive studies on MP abundance in environment, identification, and treatment, their negative effects on human health remain unknown due to the lack of proof from clinical studies and limited technology on the MP identification. To assess the risk of MPs to human health, the first step is to estimate MP intake via ingestion, inhalation, and dermal contact under standardized exposure conditions in daily life. Furthermore, rather than focusing on the sole MPs, migrating chemicals from plastic products should be quantified and their health risk be assessed concurrently with MP release. The critical factors influencing MP release and simultaneously exposed chemicals (SECs) must be investigated using a standardized identification method. This review summarises release sources, factors, and possible routes of MPs from the environment to the human body, and the quantification methods used in risk assessment. We also discussed the issues encountered in MP release and SEC migration. Consequently, this review provides directions for future MP studies that can answer questions about MP toxicity to human health.

Impact of accelerated weathering on the leaching kinetics of stabiliser additives from microplastics

The release of additives from microplastics is known to harm organisms. In the environment, microplastics are exposed to weathering processes which are suspected to influence additive leaching kinetics, the extent and mechanism of which remain poorly understood. We examined the impact of weathering on stabiliser additive leaching kinetics using environmentally relevant accelerated weathering and leaching procedures. Nine binary polymer-additive formulations were specifically prepared, weathered, analysed, and evaluated for their leaching characteristics. Cumulative additive release (Ce) varied widely between formulations, ranging from 0.009 to 1162 µg/g. Values of Ce generally increased by polymer type in the order polyethylene terephthalate < polyamide 6 < polyethylene. The change in leaching kinetics after accelerated weathering was incongruous across the nine formulations, with a significant change in Ce only observed for three out of nine formulations. Physicochemical characterisation of the microplastics demonstrated that additive blooming was the primary mechanism influencing the leaching response to weathering. These findings highlight the dependency of additive fate on the polymer type, additive chemistry, and the extent of weathering exposure. This has significant implications for risk assessment and mitigation, where the general assumption that polymer weathering increases additive leaching may be too simplistic.

From oceans to dinner plates: The impact of microplastics on human health

Microplastics, measuring less than 5 mm in diameter, are now found in various environmental media, including soil, water, and air, and have infiltrated the food chain, ultimately becoming a part of the human diet. This study offers a comprehensive examination of the intricate nexus between microplastics and human health, thereby contributing to the existing knowledge on the subject. Sources of microplastics, including microfibers from textiles, personal care products, and wastewater treatment plants, among others, were assessed. The study meticulously examined the diverse routes of microplastic exposure-ingestion, inhalation, and dermal contact-offering insights into the associated health risks. Notably, ingestion of microplastics has been linked to gastrointestinal disturbances, endocrine disruption, and the potential transmission of pathogenic bacteria. Inhalation of airborne microplastics emerges as a critical concern, with possible implications for respiratory and cardiovascular health. Dermal contact, although less explored, raises the prospect of skin irritation and allergic reactions. The impacts of COVID-19 on microplastic pollution were also highlighted. Throughout the manuscript, the need for a deeper mechanistic understanding of microplastic interactions with human systems is emphasized, underscoring the urgency for further research and public awareness.

Will the aging products of soil-reinforcement fibers stress plant growth and soil health?

Soil-reinforcement fibers are widely used for soil remediation and erosion prevention in ecologically vulnerable regions with sparse vegetation coverage and are incorporated into the soil for prolonged periods. However, the potential risks posed by aging fiber materials to soil health and plant growth have been largely neglected. This study explored the effects of aging solutions for polyethylene terephthalate (PET), coir, and carbon fibers on the physiological characteristics and vegetation coverage of ryegrass, as well as soil properties. Results indicated that PET and carbon fibers decreased ryegrass density and inhibited chlorophyll synthesis. All three fiber aging solutions aggravated leaf peroxidation, as represented by a sharp increase in the malondialdehyde (MDA) content. Leaf peroxidase activities improved, whereas the ascorbate peroxidase (APX) and superoxide dismutase (SOD) activities under the carbon fiber treatment were significantly lower than those under the PET and coir fiber treatments. The three fiber aging solutions significantly reduced soil H2O2 activity, improved soil leucine aminopeptidase (LAP) activity. Besides, coir fiber aging solution improved soil hemicellulose (CB) activity significantly. Aging solutions of PET and coir fibers increased the number of soil bacterial colonies, while the carbon fiber aging solution increased the number of soil actinomyces colonies. Overall, our findings demonstrate that fiber aging solutions decrease plant density, cause leaf damage, and alter soil characteristics in the short term. However, these solutions have minimal impact on soil health. The coir fiber aging solution has minimal effects on plant growth and soil properties, and is still a viable alternative to traditional non-degradable soil-reinforcing fibers.

Patterns and variability in the microplastic contamination along the southwest coast of India with emphasis on submarine groundwater discharge sites

Beach sediments of the southwest coast of India were analysed to estimate the microplastic contamination with emphasis on the submarine groundwater discharge (SGD) zones. Both SGD and non-SGD sites were assessed for abundance, morphotype and polymer type of microplastics. Microplastic load was 230.429 ± 62.87 particles per 100 g. Fibre, mainly blue, was the abundant morphotype, followed by fragment, foam and film. The polymer types were POLYETHYLENE (PE) (30.77 %), POLYPROPYLENE (PP) (26.92 %), POLYAMIDE (PA) (19.23 %), POLYSTYRENE (PS) (11.54 %), ETHYLENE VINYL ACETATE (EVA) (7.692 %) and POLYVINYL CHLORIDE (PVC) (3.846 %). The SGD zones exhibited higher microplastic contamination with statistically significant variations from non SGD sites. The study accounts the levels of microplastic contamination along the southwest coast of India, a major fishery zone. The higher abundance of microplastic in the SGD zones indicates the significance of subterranean groundwater through flow as a pathway of anthropogenic contaminants towards marine ecosystems.

A review of microplastic removal from water and wastewater by membrane technologies

Microplastics (MPs) cannot be completely removed from water/wastewater in conventional wastewater treatment plants (WWTPs) and drinking water treatment plants (DWTPs). According to the literature analysis, membrane technologies, one of the advanced treatment technologies, are the most effective and promising technologies for MP removal from water and wastewater. In this paper, firstly, the properties of MPs commonly present in WWTPs/DWTPs and the MP removal efficiency of WWTPs/DWTPs are briefly reviewed. In addition, research studies on MP removal from water/wastewater by microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO), and membrane bioreactors (MBRs) are reviewed. In the next section, membrane filtration is compared with other methods used for MP removal from water/wastewater, and the advantages/disadvantages of the removal methods are discussed. Moreover, the problem of membrane fouling with MPs during filtration and the potential for MP release from polymeric membrane structure to water/wastewater are discussed. Finally, based on the studies in the literature, the current status and research deficiencies of MP removal by membrane technologies are identified, and recommendations are made for further studies.

Risk assessment of microplastic pollution in an industrial region of Bangladesh

Despite the high potential for microplastics (MPs) pollution in Bangladesh, the presence of MPs in the industrial region has largely been unexplored in Bangladesh. So, this study was conducted to determine whether MP pollution is prevalent in the industrial soil of Bangladesh and the extent of its toxicity. To examine MPs, a total of 12 soil samples were collected from the industrial region of Narayanganj, and a stereoscopic microscope was used to visually identify the MPs. Prior to that the technique of density separation and sieving was applied to extract MPs from those 12 soil samples. Among the twelve investigated samples, a total of 151 MPs (Mean: 12.6 ± 7.9 particles kg^-1) were identified, which were mostly white and ranged in size from 0.5 to 1 mm. Different types of MPs according to their shapes such as fibers (60.3%), fragments (19.2%), films (10.6%), and foam (9.9%) have been detected. 7 MPs (Mean: 0.58 ± 0.79) have been found in 3 urban farmland sites, 15 MPs (Mean: 1.87 ± 1.81) in two near metropolitan areas, and 129 MPs (Mean: 4.6 ± 4.39) in 7 industrial locations. Five polymers were identified by μ-FTIR, among which Polyamide predominated, followed by Polypropylene. According to risk assessments, the region falls under hazard categories II and III, suggesting a moderate to high risk. This paper gives thorough information on the toxicity of MP in an industrial location; therefore, it may be useful in the development of effective methods to address environmental issues.

Developing and testing a workflow to identify microplastics using near infrared hyperspectral imaging

The analysis of microplastics (MP) is time-consuming which limits our capacity to monitor and mitigate plastic pollution. Here, near infrared (1000-2500 nm) hyperspectral imaging (NIR-HSI) offers an advantage over other spectroscopic techniques because it can rapidly image large areas relative to other systems. While NIR-HSI can successfully detect MP, accuracy and limitations of the method have not been fully explored. In addition, lack of open databases and analysis pipelines increases the barrier to use. In this work, we developed a spectral database containing preproduction pellets, consumer products and marine plastic debris, imaged using a Hyspex SWIR-320me imager. A SIMCA model identified four polymer types: polypropylene, polyethylene, polyethylene terephthalate and polystyrene (PP, PE, PET, PS) to identify MP in hyperspectral images. We determined the accuracy of size estimates for PS MP > 1000 μm using fluorescence microscopy and tested the impact of photooxidation on detection of plastics by NIR-HSI (PE, PP, PS, PET) and subsequent prediction by the SIMCA model. The model performed well across all polymers as shown by high specificity, sensitivity, and accuracy for internal cross validation (>88%), and sensitivity >80% for external validation. PS MP < 500 μm Feret diameter were not consistently detected by NIR-HSI when compared with fluorescence microscopy. However, estimates for Feret diameter were consistent for PS MP > 1000 μm. Analysis by NIR-HSI showed no spectral changes and SIMCA showed no decreased precision with increased photooxidation across polymer types. Recall varied across polymer type and photooxidation stage with no clear trends. This study shows that NIR-HSI is a rapid method which can accurately identify MP of the four most relevant polymer types, precluding the need to analyze particles one at a time. NIR-HSI can be a key technology for environmental monitoring of plastic debris where rapid analysis of multiple samples is required.

Dermal exposure to bisphenols in pregnant women's and baby clothes: Risk characterization

Textile manufacturing consists of a multiple-step process in which a wide range of chemicals is used, some of them remaining in the final product. Bisphenols (BPs) are non-intentionally added compounds in textiles, whose prolonged skin contact may mean a significant source of daily human exposure, especially in vulnerable groups of the population. The present study aimed to determine the levels of bisphenol A (BPA) and some BP analogs (BPB, BPF, and BPS) in 120 new clothes commercialized in Spain for pregnant women, newborns, and toddlers. In addition, exposure assessment and risk characterization were also carried out. Traces of BPA were found in all the samples, with a median concentration of 7.43 ng/g. The highest values were detected in textile samples made of polyester. Regarding natural fibers, higher concentrations of BPs were observed in garments made of conventional cotton than in those made of organic cotton, with a significant difference for BPS (1.24 vs. 0.76 ng/g, p < 0.05). Although toddlers have a larger skin-area-to-body-weight ratio, pregnant women showed higher exposure to BPs than children. Anyhow, the non-carcinogenic risks associated with BPA exposure were below the unity, even under the upper-bound scenario. However, risks could be underestimated because other exposure routes were not considered in this study. The use of BPA has been restricted in some food-related products; therefore, BPA should also be regulated in the textile industry.

Microplastic contamination in edible clams from popular recreational clam-digging sites in Hong Kong and implications for human health

The ubiquitous presence of microplastics in edible bivalves and the human health risks associated with bivalve consumption have raised public concerns. Farmed and market-sold bivalves have received the most attention, while wild bivalves have received much less scrutiny. In the present study, 249 individuals were examined across six wild clam species from two popular recreational clam-digging sites in Hong Kong. Of the clams, 56.6 % contained microplastics, with an average abundance of 1.04 items/g (wet weight) and 0.98 items/individual. This resulted in an estimated annual dietary exposure of 14,307 items per Hong Kong resident. Moreover, the potential microplastic risks for humans associated with wild clam consumption were assessed using the polymer hazard index, and the results indicated a medium degree of risk, indicating that exposure to microplastics through wild clam consumption is inevitable and poses a potential health threat to humans. Further research is needed to facilitate a better understanding of the widespread occurrence of microplastics in wild bivalves, and further refinements of the risk assessment framework can hopefully allow a more accurate and holistic health risk assessment for microplastics.

Recent analytical techniques, and potential eco-toxicological impacts of textile fibrous microplastics (FMPs) and associated contaminates: A review

Despite of our growing understanding of microplastic's implications, research on the effects of fibrous microplastic (FMPs) on the environment is still in its infancy. Some scientists have hypothesized the possibility of natural textile fibres, which may act as one of the emerging environmental pollutants prevalent among microplastic pollutants in the environment. Therefore, this review aims to critically evaluate the toxic effects of emerging FMPs, the presence, and sources of FMPs in the environment, identification and analytical techniques, and the potential impact or toxicity of the FMPs on the environment and human health. About175 publications (2011-2023) based on FMPs were identified and critically reviewed for transportation, analysis and ecotoxicological behaviours of FMPs in the environment. Textile industries, wastewater treatment plants, and household washing of clothes are significant sources of FMPs. In addition, various characterization techniques (e.g., FTIR, SEM, RAMAN, TGA, microscope, and X-Ray Fluorescence Spectroscopy) commonly used for the identification and analysis of FMPs are also discussed, which justifies the novelty aspects of this review. FMPs are pollutants of emerging concern due to their prevalence and persistence in the environment. FMPs are also found in the food chain, which is an alarming situation for living organisms, including effects on the nervous system, digestive system, circulatory system, and genetic alteration. This review will provide readers with a comparison of different analytical techniques, which will be helpful for researchers to select the appropriate analytical techniques for their study and enhance their knowledge about the harmful effects of FMPs.

On the horns of a dilemma: Evaluation of synthetic and natural textile microfibre effects on the physiology of the pacific oyster Crassostrea gigas

Fast fashion and our daily use of fibrous materials cause a massive release of microfibres (MF) into the oceans. Although MF pollution is commonly linked to plastics, the vast majority of collected MF are made from natural materials (e.g. cellulose). We investigated the effects of 96-h exposure to natural (wool, cotton, organic cotton) and synthetic (acrylic, nylon, polyester) textile MF and their associated chemical additives on the capacity of Pacific oysters Crassostrea gigas to ingest MF and the effects of MF and their leachates on key molecular and cellular endpoints. Digestive and glycolytic enzyme activities and immune and detoxification responses were determined at cellular (haemocyte viability, ROS production, ABC pump activity) and molecular (Ikb1, Ikb2, caspase 1 and EcSOD expression) levels, considering environmentally relevant (10 MF L^-1) and worst-case scenarios (10 000 MF L^-1). Ingestion of natural MF perturbed oyster digestive and immune functions, but synthetic MF had few effects, supposedly related with fibers weaving rather than the material itself. No concentration effects were found, suggesting that an environmental dose of MF is sufficient to trigger these responses. Leachate exposure had minimal effects on oyster physiology. These results suggest that the manufacture of the fibres and their characteristics could be the major factors of MF toxicity and stress the need to consider both natural and synthetic particles and their leachates to thoroughly evaluate the impact of anthropogenic debris. Environmental Implication. Microfibres (MF) are omnipresent in the world oceans with around 2 million tons released every year, resulting in their ingestion by a wide array of marine organisms. In the ocean, a domination of natural MF- representing more than 80% of collected fibres-over synthetic ones was observed. Despite MF pervasiveness, research on their impact on marine organisms, is still in its infancy. The current study aims to investigate the effects of environmental concentrations of both synthetic and natural textile MF and their associated leachates on a model filter feeder.

Microplastic pollution on hiking and running trails in Australian protected environments

Microplastics (MPs) are ubiquitous worldwide, present even in remote areas of the natural environment. Hiking and trail running are a source of MPs on recreational trails in protected environments, which are characterised by high biodiversity and natural, ecological or cultural significance. Our understanding of the risks of microplastic pollution is impeded however by a lack of information on MPs present in the soil environment in such areas. This study characterised the quantity and physicochemical characteristics of MPs in two conservation areas in south-eastern Australia: 1) the adjacent Duval Nature Reserve and Dumaresq Dam Reserve, and 2) the Washpool and Gibraltar Range National Parks. We measured atmospheric deposition over a six-month period in the Reserves, and baseline amounts of MPs on recreational trails in the Reserves and National Parks. Atmospheric deposition averaged 17.4 MPs m^-2 day^-1 and was dominated by fibres, comprising 84 % of MPs. Microplastics detected on trail surfaces ranged from 162.5 ± 41.6 MPs/linear metre to 168.7 ± 18.5 MPs/linear metre and exhibited a very wide range of physical and chemical characteristics. The majority of MPs on the trail surfaces comprised polyurethane, polyethylene terephthalate and polystyrene, and 47-71 % were fibres. Microplastics were attributed to clothing, footwear, litter, and diffuse sources. Minimising and preventing MP pollution, however, is complex given there are multiple direct and diffuse sources, and several factors influencing increased MP deposition and retention in the environment.

Solving a microplastic dilemma? Evaluating additive release with a dynamic leaching method for microplastic assessment (DyLeMMA)

Microplastics and plastic additives are contaminants of emerging environmental concern. Static leaching methods are commonly applied to assess the rate and extent of additive release from microplastics. However, this approach may not be representative of environmental conditions where near infinite dilution or percolation commonly occur. We evaluated three different approaches for assessing additive leaching under environmentally relevant sink conditions, culminating in the refinement and validation of DyLeMMA (Dynamic Leaching Method for Microplastic Assessment). Analysis was performed using a high-resolution liquid chromatography-mass spectrometry method enabling targeted quantification of additives and screening for non-intentionally added substances. Using four different plastics, sink conditions were maintained over the duration of the test, thereby avoiding solubility limited release and ensuring environmental relevance. Background contamination from ubiquitous additive chemicals was minimised, thereby providing good sensitivity and specificity. Resulting data, in the form of additive release curves, should prove suitable for fitting to release models and derivation of parameters describing additive leaching from microplastics.Key attributes of DyLeMMA:•Environmentally relevant dynamic leaching method for microplastics, demonstrated to maintain sink conditions over the test duration,•Simple, fast, and cost-effective approach without complication of using a solid phase sink,•Provide data suitable for understanding microplastic leaching kinetics and mechanisms.

In situ biomonitoring using caged lumpfish (Cyclopterus lumpus) eggs reveal plastic and rubber associated chemicals in a harbour area in Central Norway

Plastics- and rubber-derived chemicals are given increasing focus due to their migration into the environment and potential for causing detrimental effects. The current study demonstrates the use of a novel biomonitoring platform using caged fertilized eggs of lumpfish (Cyclopterus lumpus) in combination with gas chromatography tandem mass spectrometry analysis of a selection of target chemicals extracted from the lumpfish eggs after deployment. A monitoring campaign in the Trondheim harbor and off the coast of Trøndelag in Norway was executed using the described system. Here we found accumulation of UV stabilizers (benzophenone and benzothiazoles), plasticizers (n-butylbenzenesulfonamide), reagents, and polymer synthesis precursors (bisphenol A, acetophenone, phthalide, and phthalimide) in deployed eggs. Several of the compounds were detected in concentrations above previously quantified legacy contaminants in the same study areas.

Effects of UV radiation on natural and synthetic materials

The deleterious effects of solar ultraviolet (UV) radiation on construction materials, especially wood and plastics, and the consequent impacts on their useful lifetimes, are well documented in scientific literature. Any future increase in solar UV radiation and ambient temperature due to climate change will therefore shorten service lifetimes of materials, which will require higher levels of stabilisation or other interventions to maintain their lifetimes at the present levels. The implementation of the Montreal Protocol and its amendments on substances that deplete the ozone layer, controls the solar UV-B radiation received on Earth. This current quadrennial assessment provides a comprehensive update on the deleterious effects of solar UV radiation on the durability of natural and synthetic materials, as well as recent innovations in better stabilising of materials against solar UV radiation-induced damage. Pertinent emerging technologies for wood and plastics used in construction, composite materials used in construction, textile fibres, comfort fabric, and photovoltaic materials, are addressed in detail. Also addressed are the trends in technology designed to increase sustainability via replacing toxic, unsustainable, legacy additives with 'greener' benign substitutes that may indirectly affect the UV stability of the redesigned materials. An emerging class of efficient photostabilisers are the nanoscale particles that include oxide fillers and nanocarbons used in high-performance composites, which provide good UV stability to materials. They also allow the design of UV-shielding fabric materials with impressive UV protection factors. An emerging environmental issue related to the photodegradation of plastics is the generation of ubiquitous micro-scale particles from plastic litter exposed to solar UV radiation.

Exploring the presence and distribution of microplastics in subterranean estuaries from southwest India

Rivers, surface runoff, and the wind all transport microplastics (MPs) to the ocean. There is a knowledge gap concerning the distribution of microplastics in transitional subterranean estuaries. Here, we report the presence of microplastics in the pore water, groundwater, and sea water from four locations in southwest India. Pore water, groundwater, and seawater had mean MP abundances (± standard deviations) of 0.75 (±0.66), 0.15 (±0.1), and 0.11 (±0.07) MPs/l, respectively. Fibres were the dominant category of MPs found. Fourier-transformed infrared spectroscopy revealed the presence of polymers like polyester, low-density polyethylene, and polystyrene. Possible sources of microplastic are fishing activities, tourism, and coastal residents. The microplastics-derived risk assessment scores indicate severe risk to the ecosystems. Fibrous microplastics in pore water indicate that these linear particles can migrate vertically through sandy sediments, reaching subterranean estuaries. We believe submarine groundwater discharge can act as a possible pathway for microplastics to enter the oceans.

Fibrous microplastics released from textiles: Occurrence, fate, and remediation strategies

Microplastics (MP), i.e., particles measuring less than 5 mm in size, are considered emerging pollutants. The ubiquity of MP is causing great concern among environmental and public health agencies. Anthropogenic activities are responsible for the extensive dispersal of MP in nature. Adverse effects on living organisms, interactions with other contaminants occurring in the environment, and the lack of effective degradation/removal techniques are significant issues related to MP. Most MP found in nature are fibrous (FMP). FMP originate from textile products, mainly synthetic fibers (e.g., polyester). Synthetic fibers are intensively used to produce countless goods due to beneficial characteristics such as high mechanical resistance and economic feasibility. FMP are ubiquitous on the planet and impart lasting adverse effects on biodiversity. Data on the consequences of long-term exposure to these pollutants are scarce in the literature. In addition, few studies address the main types of synthetic microfibers released from textiles, their occurrence, adverse effects on organisms, and remediation strategies. This review discusses the relevant topics about FMP and alerts the dangers to the planet. Furthermore, future perspectives and technological highlights for the FMP mitigation/degradation are presented.

Sustainable Innovation: Turning Waste into Soil Additives

In recent years, a dynamic increase in environmental pollution with textile waste has been observed. Natural textile waste has great potential for environmental applications. This work identifies potential ways of sustainably managing natural textile waste, which is problematic waste from sheep farming or the cultivation of fibrous plants. On the basis of textile waste, an innovative technology was developed to support water saving and plant vegetation- biodegradable water-absorbing geocomposites (BioWAGs). The major objective of this study was to determine BioWAG effectiveness under field conditions. The paper analyses the effect of BioWAGs on the increments in fresh and dry matter, the development of the root system, and the relative water content (RWC) of selected grass species. The conducted research confirmed the high efficiency of the developed technology. The BioWAGs increased the fresh mass of grass shoots by 230-420% and the root system by 130-200% compared with the control group. The study proved that BioWAGs are a highly effective technology that supports plant vegetation and saves water. Thanks to the reuse of waste materials, the developed technology is compatible with the assumptions of the circular economy and the goals of sustainable development.

Characterization of fiber fragments released from polyester textiles during UV weathering

Synthetic textiles are considered a prime source of microplastics fibers which are a prevalent shape of microplastic pollution. Whilst the release mechanisms and formation of such microplastic fibers have been so far mainly studied in connection with laundry washing, there are some studies emerging that describe also other release pathways for microplastic fibers such as abrasion during wearing. The aim of this study was to consider weathering as another process contributing to the formation of microplastic fibers and their presence in the environment. Four types of polyester fabrics were selected and exposed to artificial weathering by UV-light for two months. The fabrics were extracted every 15 days to quantify and characterize the formed microplastics. Microplastic fibers with the diameter matching the size of the fibers in the textiles were observed. However, additional microplastic fibers of different shapes were also formed. These included partially broken fibers, thin fibers with a diameter below the size of the fiber in the fabrics, fibers flattened into a ribbon, and non-fibrous microplastics. The released microplastics evinced physical alterations on their surface in the form of pits and cracks. The released microplastics exhibited a steep increase in number with progressing weathering; from hundreds of fibers per gram of textile from unaged fabrics, to hundred thousands fibers (150,000-450,000 MPF/g) after 2 months of weathering. Additional 10,000-52,000 unfibrous microplastics/g were released from the weathered fabrics. While plain fabrics showed higher releases than interlock and fleece, further research is needed to evaluate the importance of the textile architecture on the weathering process in comparison with the production history of the fabrics. Based on a comparison with washing studies with the same textiles, we can estimate that the potential of weathered fabrics to be a source of microplastic fibers can be 20-40 times larger than washing only.

Insights into sorption and molecular transport of atrazine, testosterone, and progesterone onto polyamide microplastics in different aquatic matrices

Microplastics can act as vectors of a wide class of contaminants in aquatic environments. The sorption behavior of two hormones known to cause adverse effects in biota even in low concentrations (testosterone-TTR and progesterone-PGT), and a pesticide with a high environmental persistence known as endocrine disruptor chemical (atrazine-ATZ) onto polyamide (PA) microplastics is investigated under different aquatic matrices using kinetic and isotherm experiments. The sorption equilibrium is achieved in 48 h, and the experimental results are better fitted by pseudo-2nd-order model. Langmuir isotherm better describes the sorption of the contaminants onto PA microplastics. PGT presents the highest sorption efficiency at around 90%, followed by TTR at 70% and ATZ at approximately 20%. Moreover, ATZ is the contaminant with the highest desorption efficiency (∼65%), indicating its preference for staying solubilized in water. Combining classical molecular dynamics and density functional theory calculations, the sorption energies were calculated as 12-15 kcal mol^-1, 13-16 kcal mol^-1, and 19-22 kcal mol^-1 for PGT, TTR, and ATZ, respectively, showing that PGT needs less energy to be transferred from the solvent network to the PA surface, in agreement with experimental results. The sorption mechanism is driven by hydrogen bonds onto PA outer surface, while the electrostatic interactions dominate the PA inner surface sorption. Moreover, the sorption efficiency is statistically different between the investigated matrices, indicating that physicochemical characteristics of water systems could influence the interactions between PA-contaminant. In seawater, the phenomena of salting-out/in and competitive sorption with saline ions are observed for three contaminants. The PA-contaminant complexes are more polar and soluble than the dissociated ones, which increases the contaminant's co-transport by PA in water.

Microplastics in mussels from the Boka Kotorska Bay (Adriatic Sea) and impact on human health

This study evaluated the microplastic abundance, shape, color, size and chemical composition of microplastic in mussels and estimated human exposure to microplastic through consumption of mussels collected from Boka Kotorska Bay (Adriatic coast of Montenegro). Microplastic was found in 53.3% of the studied mussels, with an average microplastic abundance of 2.53 ± 1.1 items/individual. Most of the ingested microplastic were fibers (63.7%), which were blue in color. FT-IR revealed that 98% of the examined particles were plastic, with seven polymers identified, of which polyethylene, polypropylene, and polyethylene terephthalate were the most abumdant polymers in mussels. Three of the polymers detected in mussels (polyamide, polyvinyl chloride and polystyrene) are classified as hazardous by the European Chemical Agency with warning or danger signals. With one serving of mussels, consumers would ingest 22.7 microplastic particles, while the annual dietary intake of microplastic via consumption of mussels was estimated at 99 MP/year.

Formation of Nano- and Microplastics and Dissolved Chemicals During Photodegradation of Polyester Base Fabrics with Polyurethane Coating

Polyurethane (PU) synthetic leathers possess an intricate plastic composition, including polyester (PET) base fabrics and upper PU resin, but the release of fragments from the complexes is unclear. Therefore, we investigated the photodegradation trends of PET base fabrics with PU coating (PET-U) as a representative of composite plastics. Attention was paid to the comparison of the photoaging process of PET-U with that of pure PET base fabric (PET-P). To reveal the potential for chain scission, physical and chemical changes (e.g., surface morphology, molecular weight, and crystallinity) of the two fabrics were explored. The generation of microplastic fibers (MPFs) and microplastic particles (MPPs) was distinguished. Compared with PET-P, PET-U showed a similar but delayed trend in various characteristics and debris release rate as the photoaging time prolonged. Even so, after 360 h of illumination, the generated number of MPs (including MPFs and MPPs) rose considerably to 9.32 × 10⁷ MPs/g, and the amount of released nanoplastics (NPs) increased to 2.70 × 10¹¹ NPs/g from PET-U. The suppression of MP formation from PET-U was potentially directed by the physical shielding of the upper PU layer and the dropped MPs, which resisted the photochemical radical effect. The components of dissolved organic matter derived from plastics (P-DOM) were separated by molecular weight using a size-exclusion chromatography-diode array detector-organic carbon detector/organic nitrogen detector (SEC-DAD-OCD/OND), and the results showed that a larger amount of carbon- and nitrogen-containing chemical substances were generated in PET-U, accompanied by more aromatic and fluorescent compounds. The results provided theoretical bases and insights for future research on the risks of plastic debris from PU synthetic leathers on aquatic organisms and indicated feasible directions for exploring combined pollution studies of plastics.

Spectroscopic Tracking of the Characteristics of Microplastic-Derived Dissolved Organic Matter

Microplastic-derived dissolved organic matter (MP-DOM) has received increasing attention in recent years. In this study, the fluorescence excitation-emission matrix (EEM) combined with parallel factor analysis (PARAFAC) was used to track the leaching behavior of polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), polyethylene terephthalate (PET), and polystyrene (PS) MP-DOM. After seven days of leaching, PVC reached a leaching concentration of 7.59 mg/L, and the other four microplastics reached approximately 4.5~4.7 mg/L. The leaching activity of PVC was considerably more active in an alkaline environment and under UV irradiation. All the fluorescence signals of MP-DOM components were located in the protein/phenol-like fluorescence region. The fact that C1 and C2 were found in every microplastic revealed that these substances took up quite a large proportion of MP-DOM. Protein/phenolic substances in MP-DOM showed different binding ability with different heavy metals, which can be realized from the log K values calculated for Cr3+ (3.99–5.51), Cu2+ (3.06–4.83), Cd2+ (3.76–4.41), and Fe3+ (3.11–5.03). This work introduced more MP-DOM samples, and offered spectroscopic insight into the characteristics and environmental fate of MP-DOM at a molecular level. Furthermore, this study displayed the potential applicability of using the integrated methods to track the MP-DOM formation process and environmental behavior in natural aquatic systems.

Impact of coastal wastewater treatment plants on microplastic pollution in surface seawater and ecological risk assessment

This study aims to understand the influence of wastewater treatment plant discharge on the microplastic status in the surface seawater of Istanbul. For this purpose, for the first time, the distribution, composition, and ecological risk of microplastics at nine sampling stations on the southern coast of Istanbul, Marmara, were investigated at monthly intervals over a one-year period. The results showed that the microplastic abundance ranged from 0 to over 1000 particles per liter. Fibers were the dominant form at all stations. Microplastics 249-100 μm were the dominant size, and transparency was the color most found at all stations. Polyethylene and ethylene-vinyl acetate were the major types of microplastics, accounting for 50% overall. The pollution load index revealed that over 70% of sampling stations were at hazard level I. However, the hazardous index was categorized as level III with a value of 662.3 due to the presence of the most hazardous polymer named polyurethane. Further investigations into the risk assessment of MP can reveal crucial knowledge for understanding the microplastic cycle.

Atmospheric microfibers dominated by natural and regenerated cellulosic fibers: Explanations from the textile engineering perspective

A large number of synthetic fibers found in the environment have aroused public conern about microfiber pollution. However, more studies have found that the number of natural fibers and regenerated cellulose fibers in the environment is much higher than that of synthetic fibers. If humans are exposed to excessive amounts of these two types of fibers for a long time, they may also suffer physiological injury. However, this is often ignored by previous research on microfiber pollution. Recently, some publications attributed the dominating amounts of natural fiber and regenerated cellulosic fibers in the environment to the past yield advantage and low durability compared to synthetic fibers. This correspondence supports that view and further discusses the main reasons for the domination of natural and regenerated cellulosic fibers: their physicochemical properties, material sources, manufacturing processes (staple yarn and filament) and applications. This correspondence aims to arouse attention to the potential impact of natural fibers and regenerated cellulose fibers.