Small microplastics (<100 μm), plasticizers and additives in seawater and sediments: Oleo-extraction, purification, quantification, and polymer characterization using Micro-FTIR

Integrated occurrence of contaminants of emerging concern, including microplastics, in urban and agricultural watersheds in the State of São Paulo, Brazil

Contaminants of emerging concern (CECs), including microplastics, have been the focus of many studies due to their environmental impact, affecting biota and human health. The diverse land uses and occupation of watersheds are important parameters driving the occurrence of these contaminants. CECs such as pesticides, drugs, hormones, and industrial-origin substances were analyzed in urban/industrial (Atibaia) and agricultural (Preto/Turvo) watersheds located in São Paulo state, Brazil. A total of 24 CECs were investigated, and, as a result, only 5 (caffeine, carbendazim, atrazine, ametrine and 2-hydroxytrazine) were responsible for 81.73 % of the statistical difference between watersheds contamination profile. The Atibaia watershed presented considerable concentrations of caffeine (ranging from 75 to 2025 ng L-1), while carbendazim (44 to 1144 ng L-1) and atrazine (3 to 266 ng L-1) presented highest levels in Preto/Turvo watershed. In all sampling points, the cumulative potential aquatic life risk assessed by the NORMAN database indicates some level of environmental concern associated to pesticides and caffeine (risk quotient >1). Microplastics had been analyzed in both watersheds, being the white/transparent fragments in size between 100 and 250 μm the most detected in this study. The estimated abundance in the Atibaia watershed ranged from 349 to 2898 items m-3 presenting some influence of pluviosity, while in Rio Preto/Turvo ranged from 169 to 6370 items m-3, being more abundant in the dam area without a clear influence of pluviosity. In both basins, polyethylene and polypropylene were the most detected polymers, probably due to the intense use of single-use plastics in urban areas. Possibly, due to the distinct physic-chemical properties of microplastics and organic CECs, no correlations were observed between their occurrence, which makes us conclude that they have different transport mechanism, behavior, and fate in the environment.

Analysis of microplastics in commercial vegetable edible oils from Italy and Spain

In this work, assessment of microplastics (MPs) in commercial vegetable edible oils from Italy and Spain, including extra-virgin olive oil, olive oil, sunflower oil, and mixed seed oil, has been conducted for the first time. The method was based on sample dilution with ethanol:n-hexane (1:3, v/v), homogenization, vacuum filtration on macroporous silicon filters with 5 μm pore diameter to collect MPs, and automatic µ-FTIR spectroscopy for MPs detection and characterization. In the analysis of oil samples, a mean MPs abundance of 1140 ± 350 MPs/L was found. Observed MPs were characterized, being most of them fragments (81.2 %), with particle sizes < 100 µm (77.5 %), and mainly composed of polyethylene (50.3 %) and polypropylene (28.7 %), among others. Statistical analysis revealed that there were not significant differences (p-value > 0.05) in the abundance of MPs between oil samples or types.

Microplastic pollution in surface sediments of Coromandel coastline, South-East Coast, India: Diversity index, carbonyl index, pollution load index, risk fraction and MPs inventory

The investigation along the Coromandel coastline of South-east India focused on assessing microplastics abundance using Simpson's diversity index (DIMP), Degradation-carbonyl index (DgCIMP), Pollution load index (PLIMP) and Ecological risk fraction (RfMP). These indices evaluated the dissemination and transportation of MPs across a 1076 km stretch divided into five zones from Chennai to Kanyakumari. During the wet season, average microplastics abundance (101 ± 36.6 items/kg dw) was lower compared to the dry season (143 ± 56.2 items/kg dw). Notably, 54% and 45% of microplastics were found in the 0.1-0.5 mm size range, with 45% and 64% being colored microplastics, and 80% and 71% being fibers during the wet and dry seasons respectively. Micro-Fourier-transform infrared spectroscopy (μFTIR) analysis showed rayon (34%) and PE (64%) dominance in ports and estuaries during both seasons. Kottaipattinam Port exhibited higher diversity indices (DIMPsh=0.56,DIMPsz=0.66,DIMPco=0.50andDIMPpo=0.65) compared to other zones, with an overall diversity index IDIMP of 0.57. Notably, among the DgCIMP values (n = 96), only 12 fell within the moderate photo-chemical oxidation range (0.16-0.35), while the majority (n = 60) surpassed 0.35 indicating higher oxidation levels, with some (n = 24) exceeding 0.50, signifying extreme oxidation. PLIMP revealed that 42% of sampling stations had very low to negligible MP contamination levels in ports and estuaries. However, ecological risk fraction RfMP values ranged from 10.2 to 13,670, with 27% of values exceeding 1500, indicating higher coastal ecological risk in 13 sampling stations.

Microplastic accumulation and ecological impacts on benthic invertebrates: Insights from a microcosm experiment

Microplastic (MP) pollution poses a global concern, especially for benthic invertebrates. This one-month study investigated the accumulation of small MP polymers (polypropylene and polyester resin, 3-500 μm, 250 μg L-1) in benthic invertebrates and on one alga species. Results revealed species-specific preferences for MP size and type, driven by ingestion, adhesion, or avoidance behaviours. Polyester resin accumulated in Mytilus galloprovincialis, Chamelea gallina, Hexaplex trunculus, and Paranemonia cinerea, while polypropylene accumulated on Ulva rigida. Over time, MP accumulation decreased in count but not size, averaging 6.2 ± 5.0 particles per individual after a month. MP were mainly found inside of the organisms, especially in the gut, gills, and gonads and externally adherent MP ranged from 11 to 35 % of the total. Biochemical energy assessments after two weeks of MP exposure indicated energy gains for water column species but energy loss for sediment-associated species, highlighting the susceptibility of infaunal benthic communities to MP contamination.

The quantification of the airborne plastic particles of 0.43-11 μm: Procedure development and application to atmospheric environment

The environmental degradation of microplastics results in ultrafine particles that may incur severe biological concerns. Despite this, the atmospheric existence of plastics of less than a few microns has barely been investigated due to the particle size limit of conventional analytical methods. This study develops a procedure to quantify and characterize plastic particles (including nanoplastics; less than 1 μm) in the air through fractional sampling, a simple pretreatment method, and pyrolysis-gas chromatography-mass spectrometry (pyr-GC/MS). We targeted 11 major polymers, namely, polyethylene, polypropylene, polystyrene, acrylonitrile-butadiene-styrene resin, styrene-butadiene rubber, polymethylmethacrylate, polycarbonate, polyvinyl chloride, polyethylene terephthalate (PET), polyamide 6, and polyamide 66 (PA66). The average spike and recovery rate of each polymer in the aerosol collected on the roof of a four-story building near a major road in Kyoto, Japan, amounted to 78-130%, with a coefficient of variation of less than 15%. By coupling pyr-GC/MS analysis with fractional sampling of particles within the size range of >11 μm, 11-7.0 μm, 7.0-4.7 μm, 4.7-3.3 μm, 3.3-2.1 μm, 2.1-1.1 μm, 1.1-0.65 μm, 0.65-0.43 μm, it was possible to quantify airborne nano- and microplastics by particle size. Polyethylene, polystyrene, PET, and PA66 were detected in the air, and the total mass concentration of tiny plastic particles (0.43-11 μm) amounted to 1.20 μg/m3. This translates into total particle numbers of 3.05 × 106 particles/m3 (assuming spheres), revealing a substantial number of particles under 1 μm. These results will contribute to future studies to understand the atmospheric behaviors of ultrafine plastic particles and their flow-on effects on the respiratory system.

Methamphetamine Shows Different Joint Toxicity for Different Types of Microplastics on Zebrafish Larvae by Mediating Oxidative Stress

The coexistence of polystyrene (PS) and polypropylene (PVC) microplastics (MPs) and methamphetamine (METH) in aquatic systems is evident. However, the joint toxicity is unclear. Here, zebrafish larvae were exposed to single PS and PVC MPs (20 mg L-1) and combined with METH (250 and 500 μg L-1) for 10 days. The results indicated that acute exposure to PS and PVC MPs induced lethal effects on zebrafish larvae (10-20%). Treatment with MPs markedly suppressed the locomotion of zebrafish, showing as the lengthy immobility (51-74%) and lower velocity (0.09-0.55 cm s-1) compared with the control (1.07 cm s-1). Meanwhile, histopathological analysis revealed pronounced depositions of MPs particles in fish's intestinal tract, triggering inflammatory responses (histological scores: 1.6-2.0). In the coexposure groups, obviously inflammatory responses were found. Furthermore, the up-regulations of the genes involved in the oxidative kinase gene and inflammation related genes implied that oxidative stress triggered by MPs on zebrafish larvae might be responsible for the mortality and locomotion retardant. The antagonistic and stimulatory effects of METH on the expression changes of genes found in PVC and PS groups implied the contrary combined toxicity of PS/PVC MPs and METH. This study for the first time estimated the different toxicity of PS and PVC MPs on fish and the joint effects with METH at high environmental levels. The results suggested PS showed stronger toxicity than PVC for fish larvae. The addition of METH stimulated the effects of PS but antagonized the effects of PVC, promoting control strategy development on MPs and METH in aquatic environments.

Quantification and Chemical Characterization of Plastic Additives and Small Microplastics (<100 μm) in Highway Road Dust

Road dust is one of the environment's most important microplastic and plastic additive sources. Traffic vehicles and the wear of tires can release these emerging contaminants, which can be resuspended in the air and washed off by stormwater runoff. In this study, a concurrent quantification and chemical characterization of additives, plasticizers, natural and non-plastic synthetic fibers (APFs), and small microplastics (SMPs, <100 µm) in samples of highway road dust (HWRD) was performed. The sampling procedure was optimized, as well as pretreatment (extraction, purification, and filtration) and analysis via micro-FTIR. The average length of the SMPs was 88 µm, while the average width was 50 µm. The highest abundance of SMPs was detected in HWRD 7 (802 ± 39 SMPs/g). Among the polymers characterized and quantified, vinyl ester and polytetrafluoroethylene were predominant. APFs' average particle length was 80 µm and their width was 45 µm, confirming that both of these emerging pollutants are less than 100 µm in size. Their maximum concentration was in RD7, with 1044 ± 45 APFs/g. Lubricants and plasticizers are the two most abundant categories, followed by vulcanizing agents, accelerators, and pre-vulcanizing retarders derived mainly from tires. A potential relationship between APFs and SMPs in the different seasons was observed, as their concentration was lower in summer for both and higher in winter 2022. These results will be significant in investigating the load of these pollutants from highways, which is urgently necessary for more accurate inclusion in emission inventories, receptor modeling, and health protection programs by policymakers, especially in air and water pollution policies, to prevent risks to human health.

A recipe for plastic: Expert insights on plastic additives in the marine environment

The production and consumption of plastic products had been steadily increasing over the years, leading to more plastic waste entering the environment. Plastic pollution is ubiquitous and comes in many types and forms. To enhance or modify their properties, chemical additives are added to plastic items during manufacturing. The presence and leakage of these additives, from managed and mismanaged plastic waste, into the environment are of growing concern. In this study, we gauged, via an online questionnaire, expert knowledge on the use, characteristics, monitoring and risks of plastic additives to the marine environment. We analysed the survey results against actual data to identify and prioritise risks and gaps. Participants also highlighted key factors for future consideration, including gaining a deeper understanding of the use and types of plastic additives, how they leach throughout the entire lifecycle, their toxicity, and the safety of alternative options. More extensive chemical regulation and an evaluation of the essentiality of their use should also be considered.

Long-term release kinetic characteristics of microplastic from commonly used masks into water under simulated natural environments

Masks-related microplastic pollution poses a new threat to the environment and human health that has gained increasing concern. However, the long-term release kinetics of microplastic from masks in aquatic environments have yet to studied, which hampers its risk assessment. Four types of masks, namely cotton mask, fashion mask, N95 mask, and disposable surgical mask were exposed to systematically simulated natural water environments to determine the time-dependent microplastic release characteristics at 3, 6, 9, and 12 months, respectively. In addition, the structure changes of employed masks were examined by scanning electron microscopy. Moreover, Fourier transform infrared spectroscopy was applied to analyze the chemical composition and groups of released microplastic fibers. Our results showed that the simulated natural water environment could degrade four types of masks and continuously produce microplastic fibers/fragments in a time-dependent manner. The dominant size of released particles/fibers was below 20 μm across four types of face masks. The physical structure of all four masks was damaged to varying degrees concomitant with photo-oxidation reaction. Collectively, we characterized the long-term release kinetics of microplastic from four types of commonly used masks under a well-mimic real word water environment. Our findings suggest that urgent action must be taken to properly manage disposable masks and ultimately limit the health threats associated with discarded masks.

Identification and quantification of tire wear particles by employing different cross-validation techniques: FTIR-ATR Micro-FTIR, Pyr-GC/MS, and SEM

Tire wear particles (TWPs) are one of the environment's most important emission sources of microplastics. In this work, chemical identification of these particles was carried out in highway stormwater runoff through cross-validation techniques for the first time. Optimization of a pre-treatment method (i.e., extraction and purification) was provided to extract TWPs, avoiding their degradation and denaturation, to prevent getting low recognizable identification and consequently underestimates in the quantification. Specific markers were used for TWPs identification comparing real stormwater samples and reference materials via FTIR-ATR, Micro-FTIR, and Pyrolysis-gas-chromatography-mass spectrometry (Pyr-GC/MS). Quantification of TWPs was carried out via Micro-FTIR (microscopic counting); the abundance ranged from 220,371 ± 651 TWPs/L to 358,915 ± 831 TWPs/L, while the higher mass was 39,6 ± 9 mg TWPs/L and the lowest 31,0 ± 8 mg TWPs/L. Most of the TWPs analyzed were less than 100 μm in size. The sizes were also confirmed using a scanning electron microscope (SEM), including the presence of potential nano TWPs in the samples. Elemental analysis via SEM supported that a complex mixture of heterogeneous composition characterizes these particles by agglomerating organic and inorganic particles that could derive from brake and road wear, road pavement, road dust, asphalts, and construction road work. Due to the analytical lack of knowledge about TWPs chemical identification and quantification in scientific literature, this study significantly contributes to providing a novel pre-treatment and analytical methodology for these emerging contaminants in highway stormwater runoff. The results of this study highlight the uttermost necessity to employ cross-validation techniques, i.e., FTIR-ATR, Micro-FTIR, Pyr-GC/MS, and SEM for the TWPs identification and quantification in the real environmental samples.

Study on the Extraction Method of Microplastic System in Textile Wastewater

Microplastic pollution has become a global environmental problem. Textile microplastics are an important component of microplastic pollution, but little is known about their contamination in the industrial environment. The lack of standardized methods for detecting and quantifying textile microplastics is a major obstacle to determining the risks they pose to the natural environment. This study systematically examines the pretreatment options for the extraction of microplastics from printing and dyeing wastewater. The effectiveness of potassium hydroxide, nitric acid–hydrogen peroxide mixed solution, hydrogen peroxide, and Fenton’s reagent for the removal of organic matter from textile wastewater is compared. Three textile microplastics, polyethylene terephthalate, polyamide, and polyurethane, are studied. The effects of the digestion treatment on the physicochemical properties of textile microplastics are characterized. The separation efficiency of sodium chloride, zinc chloride, sodium bromide, sodium iodide, and sodium chloride-sodium iodide mixed solution on the textile microplastics is tested. The results showed that Fenton’s reagent achieved a 78% removal rate of organic matter from printing and dyeing wastewater. Meanwhile, it has less of an effect on the physicochemical properties of textile microplastics after digestion and is the best reagent for digestion. The zinc chloride solution achieved a 90% recovery for separating textile microplastics with good reproducibility. It does not affect the subsequent characterization analysis after separation and is the best solution for density separation.

Quantification and identification of airborne small microplastics (<100 μm) and other microlitter components in atmospheric aerosol via a novel elutriation and oleo-extraction method

The atmosphere is a significant pathway for distributing plastic particles and other micro-litter particles from their sources to other environmental compartments. There is a big gap regarding the standardized method for the quantification and identification of airborne microplastics (MPs), especially those in the range of 5-100 μm (small microplastics, SMPs) and airborne micro-litter components (MLCs), i.e., plastic additives, natural fibers and non-plastics synthetic fibers. This study aimed to develop and optimize a pre-treatment method (i.e., elutriation, oleoextraction, and purification) to extract SMPs and MLCs simultaneously from urban aerosol samples. The quantification and simultaneous chemical characterization were performed via Micro-FTIR. The method developed was then applied to two samples from different seasons, i.e., summer and late fall - winter. Micro-litter particles followed the Poisson distribution, and the fiducial limit (confidence interval) was calculated accordingly. Non-parametric statistical tests were performed to evaluate significant differences among the samples. The most abundant plastic polymers were polyethylene (HDPE) and polytetrafluoroethylene (PTFE). Among MLCs, flame retardants, UV filters, stabilizers, and rayon were identified. The results of this study will contribute significantly to establishing standardized and accredited methods to quantify and identify airborne SMPs and MLCs.

Quantification and characterization of additives, plasticizers, and small microplastics (5-100 μm) in highway stormwater runoff

Highway stormwater (HSW) runoff is a significant pathway for transferring microplastics from land-based sources to the other surrounding environmental compartments. Small microplastics (SMPs, 5-100 μm), additives, plasticizers, natural, and nonplastic synthetic fibers, together with other components of micro-litter (APFs), were assessed in HSW samples via Micro-FTIR; oleo-extraction and purification procedures previously developed were optimized to accomplish this goal. The distribution of SMPs and APFs observed in distinct HSW runoff varied significantly since rainfall events may play a crucial role in the concentration and distribution of these pollutants. The SMPs' abundance varied from 11932 ± 151 to 18966 ± 191 SMPs/L. The dominating polymers were vinyl ester (VE), polyamide 6 (PA6), fluorocarbon, and polyester (PES). The APFs' concentrations ranged from 12825 ± 157 to 96425 ± 430 APFs/L. Most APFs originated from vehicle and tire wear (e.g., Dioctyl adipate or 5-Methyl-1H-benzotriazole). Other sources of these pollutants might be pipes, highway signs, packaging from garbage debris, road marking paints, atmospheric deposition, and other inputs. Assessing SMPs in HSW runoff can help evaluating the potential threat they may represent to receiving water bodies and air compartments. Besides, APFs in HSW runoff may be efficient proxies of macro- and microplastic pollution.

Effect of dibutyl phthalate on microalgal growth kinetics, nutrients removal, and stress enzyme activities

The dibutyl phthalate (DPB) is an emerging plasticizer contaminant that disrupts the biological processes of primary producers, especially phytoplankton. In this study, two microalgal species (Chlorella sp. GEEL-08 and Tetradesmus dimorphus GEEL-04) were exposed to various concentrations of DBP extending from 0 to 100 mg/L. The growth kinetics, N-nitrate, and P-phosphate removal efficiency were assessed. The response enzymes such as malonaldehyde (MDA) and superoxide dismutase (SOD) were also investigated. The results revealed that the Chlorella sp. GEEL-08 at 10 mg/L concentration of DBP exhibited higher growth (0.88 OD680nm) compared to T. dimorphus GEEL-04 (0.80 OD680nm). More than 94% of N and P were removed from culture media by both microalgal species. The DBP (>50 mg/L) significantly exacerbates the growth of both microalgae species and the growth inhibition ratio was in the range of 3.6%-25.9%. The SOD activity and MDA were higher in T. dimorphus culture media than in the culture media of Chlorella sp. The results reflect the hazard and the risk of plasticizers on primary producers in the ecosystem.

Occurrence and Characterization of Small Microplastics (<100 μm), Additives, and Plasticizers in Larvae of Simuliidae

This study is the first to investigate the ingestion of microplastics (MPs), plasticizers, additives, and particles of micro-litter < 100 μm by larvae of Simuliidae (Diptera) in rivers. Blackflies belong to a small cosmopolitan insect family whose larvae are present alongside river courses, often with a torrential regime, up to their mouths. Specimens of two species of blackfly larvae, Simulium equinum and Simulium ornatum, were collected in two rivers in Central Italy, the Mignone and the Treja. Small microplastics (SMPs, <100 μm), plasticizers, additives, and other micro-litter components, e.g., natural and non-plastic synthetic fibers (APFs) ingested by blackfly larvae were, for the first time, quantified and concurrently identified via MicroFTIR. The pretreatment allowed for simultaneous extraction of the ingested SMPs and APFs. Strong acids or strong oxidizing reagents and the application of temperatures well above the glass transition temperature of polyamide 6 and 6.6 (55−60 °C) were not employed to avoid further denaturation/degradation of polymers and underestimating the quantification. Reagent and procedural blanks did not show any SMPs or APFs. The method’s yield was >90%. Differences in the abundances of the SMPs and APFs ingested by the two species under exam were statistically significant. Additives and plasticizers can be specific to a particular polymer; thus, these compounds can be proxies for the presence of plastic polymers in the environment.

Environmental health impacts of microplastics exposure on structural organization levels in the human body

The ubiquitous prevalence of microplastics pollution has raised concerns about microplastics' potential risks and impacts on the global environment. However, the potential human health risks and impacts of microplastics remain largely unexplored. By providing an overview regarding the interaction of microplastics and human health, this review extends current knowledge on the potential impacts of microplastics pollution on humans from an environmental health perspective. The paper firstly presents the characteristics of microplastics as well as the status of global microplastics pollution. As for human health, the potential hazards of microplastics are reflected by toxic chemical components, vectors of contaminants, and physical damage. Extensive microplastic pollution on ecosystems due to human activities leads to inevitable human exposure, which may occur by dietary, inhalation and/or skin contact. Accordingly, microplastics exposure is closely associated with human health. This study explores the potential interactions of microplastics with the biological organization at various levels, including chemical, cellular, tissue, organ, and system levels. The review concludes by highlighting five urgent perspectives and implications for future research on microplastics: 1) Developing a standard terminology and research methods; 2) Reinforcing microplastics pollution governance; 3) Exploring innovative strategies and technologies; 4) Engaging the public and change behaviour; and 5) Adopting a transdisciplinary approach.

Recent Advances in Spectroscopic Techniques for the Analysis of Microplastics in Food

Microplastic pollution has become a worldwide concern in aquatic and terrestrial environments. Microplastics could also enter the food chain, causing potential harm to human health. To facilitate the risk assessment of microplastics to humans, it is critically important to have a reliable analytical technique to detect, quantify, and identify microplastics of various materials, sizes, and shapes from environmental, agricultural, and food matrices. Spectroscopic techniques, mainly vibrational spectroscopy (Raman and infrared), are commonly used techniques for microplastic analysis. This review focuses on recent advances of these spectroscopic techniques for the analysis of microplastics in food. The fundamental, recent technical advances of the spectroscopic techniques and their advantages and limitations were summarized. The food sample pretreatment methods and recent applications for detecting and quantifying microplastics in different types of food were reviewed. In addition, the current technical challenges and future research directions were discussed. It is anticipated that the advances in instrument development and methodology innovation will enable spectroscopic techniques to solve critical analytical challenges in microplastic analysis in food, which will facilitate the reliable risk assessment.

Quantification of microplastics in sediments from Narragansett Bay, Rhode Island USA using a novel isolation and extraction method

Microplastics are small plastic particles found ubiquitously in marine environments. In this study, a hybridized method was developed for the extraction of microplastics (45-1000 μm) from sediments using sodium bromide solution for density separation. Method development was tested using spiked microplastics as internal standards. The method was then used to extract microplastics from sediments in Narragansett Bay, Rhode Island, USA. Suspect microplastics were analyzed with Raman spectroscopy. Microplastic abundance ranged from 40 particles/100 g sediment to 4.6 million particles/100 g sediment (wet weight). Cellulose acetate fibers were the most abundant microplastic. These results are some of the first data for microplastics in Rhode Island sediments.