This international scale study measured the prevalence of indoor microplastics (MPs) in deposited dust in 108 homes from 29 countries over a 1-month period. Dust borne MPs shape, colour, and length were determined using microscopy and the composition measured using μFTIR. Human health exposure and risk was assessed along with residential factors associated with MPs via a participant questionnaire. Samples were categorised according to each country's gross national income (GNI). Synthetic polymers dominated in low income (LI) (39%) and high income (HI) (46%) while natural fibres were the most prevalent in medium income (MI) (43%) countries. Composition and statistical analysis showed that the main sources of MPs and dust were predominantly from indoor sources. Across all GNI countries, greater vacuuming frequency was associated with lower MPs loading. High income country samples returned higher proportions of polyamides and polyester fibres, whereas in LI countries polyurethane was the most prominent MPs fibre. Exposure modelling showed infants (0–2 years) were exposed to the highest MPs dose through inhalation (4.5 × 10⁻⁵ ± 3 × 10⁻⁵) and ingestion (3.24 × 10⁻² ± 3.14 × 10⁻²) mg/kg-Bw/day. Health risk analysis of constituent monomers of polymers indicates cancer incidence was estimated at 4.1–8.7 per million persons across age groups. This study's analysis showed socio-economic factors and age were dominant variables in determining dose and associated health outcomes of MPs in household dust.

Airborne microplastics (MPs) have recently drawn the attention of the scientific community due to their possible human inhalation risk. Indoor environments are of relevance as people spend about 90% of their time indoors. This study evaluated MPs concentrations in three indoor environments: houses, public transport and working places, which are representative of urban life. Sampling involved the collection of airborne particulate matter on nylon 20 μm pore size filters. Samples were first visually inspected, and particles were characterized (colour, length or area). Polymer identification was performed through μFTIR analysis. Working conditions were controlled to guarantee quality assurance and avoid background contamination. Limits of detection, recovery tests and repeatability were performed with home-made polyethylene (PE), polypropylene (PP), and polystyrene (PS) standards. The highest average MP concentrations were found in buses (17.3 ± 2.4 MPs/m³) followed by 5.8 ± 1.9 MPs/m³ in subways, 4.8 ± 1.6 MPs/m³ in houses, and 4.2 ± 1.6 MPs/m³ in the workplaces. Polyamide, PA (51%), polyester PES (48%) and PP (1%) were the polymers identified and most common in personal care products and synthetic textiles. Most of these polymers were below 100 μm in size for both fibres (64 ± 8%) and fragments (78 ± 11%). The frequency of MP particles in our study decreased with increasing size, which points to their potential as an inhalation hazard.

Seawater, sediments, and three genera of wild scleractinian corals were collected from four coral reef areas nearshore Liuqiu Island, southwestern Taiwan. Abundance, characteristics (sizes, colors, shapes, and polymer types), and enrichment of microplastics (MPs) in the corals, and their impacts on coral cover were determined. The average MPs abundances were 0.95, 0.77, and 0.36 item/g for Galaxea sp, Acropora spp, and Pocillopora sp, respectively. The MPs abundance was relatively higher on the coral surfaces than inside the skeletons, dominated by blue rayon-fibers, correspondingly observed in seawater and sediments. Large-size colorless MPs tended to be mis-ingested by Galaxea sp. (71%) compared with Pocillopora sp. (43%) and Acropora spp. (31%). The low hard coral cover (12.5%) observed at Yufu (L1) on the northeastern coastal zone nearby tourism center of Liuqiu Island where correspondingly associated with high MPs abundance in seawater (10 item/L), sediments (260 item/kg), and corals (0.60 item/g). Tourism induced sewage discharges and sailing activities significantly contributed to the MPs pollution, probably contributing to the loss of coral cover. High MPs enrichment in corals (EFMP = 25–283) shows that the marine MPs pollution can critically threaten coral reef ecosystems. Fibrous MPs present inside the coral skeleton serve as potential indicator of MPs’ impact on corals—with the dominance of textile-related rayon and polyester/PET microfibers in the coral reef zones. This study provided valuable information for coral conservation and coastal management.

Limited attention has been given to the presence of MPs in the atmospheric environment, particularly in indoor environments where people spend about 90% of their time. This study quantitatively assesses the prevalence, source and type of MPs in Australian homes with the goal of evaluating human health exposure potential. Thirty-two airborne indoor deposited dust samples were collected in glass Petri dishes from Sydney (Australia) homes, over a one-month period in 2019. Participants completed a questionnaire on their household characteristics. Samples were analysed using a stereomicroscope, a fluorescent microscope and micro-Fourier transform infrared (FTIR) spectroscopy for their colour, size, shape and composition. Inhalation and ingestion rates were modelled using US EPA exposure factors. Microplastic fibre deposition rates ranged from 22 to 6169 fibres/m²/day. Deposited dust comprised 99% fibres. The highest proportion of fibres (19%) were 200–400 μm in length. The majority were natural (42%); 18% were transformed natural-based fibres; and 39% were petrochemical based. A significant difference was observed between the deposition rate and the main floor covering (p-value <0.05). Polyethylene, polyester, polyamide, polyacrylic, and polystyrene fibres were found in higher abundance in homes with carpet as the main floor covering. Where carpet was absent, polyvinyl fibres were the most dominant petrochemical fibre type, indicating the role of flooring materials (e.g. wood varnishes) in determining MP composition. Vacuum cleaner use was significantly related to MP deposition rates (p-value <0.05). MP ingestion rates peaked at 6.1 mg/kg-Bw/year for ages 1–6, falling to a minimum of 0.5 mg/kg-Bw/year in >20 years age group. Mean inhaled MP weight and count was determined to be 0.2±0.07 mg/kg-Bw/year and 12891±4472 fibres/year. Greatest inhalation intake rates were for the <0.5-yr age group, at 0.31 mg/kg-Bw/year. The study data reveal that MPs are prevalent in Australian homes and that the greatest risk of exposure resides with young children. Notwithstanding the limited number of global studies and the different methods used to measure MPs, this study indicates Australian deposition and inhalation rates are at the lower end of the exposure spectrum.

Synthetic fibers with diameters of several tens of micrometers are the most abundant type of microplastics in the marine environment, yet the most unknown regarding dynamics in the water column. Experiments proposed here are a proof-of-concept of qualitative and quantitative characteristics of fibers’ motion in still water and in the presence of thermal convection. For 12 sets of fine fibers (nylon (1.12 g/cm³) and polyester (1.35 g/cm³), 1.9–14.8 mm long, diameters 13 and 20 μm), 84 measurements of sinking velocity in still water were acquired. In still conditions, fibers settled smoothly and slowly, preserving their initial (accidental) orientation. Sinking rates of fibers with lengths <5 mm varied between 0.5 and 3.7 mm/s (the bulk mean of 1.6 mm/s). Fibers with similar properties showed 4-fold different sinking velocity, which is supposed to be the effect of their different orientation while settling: vertically oriented fibers (19% in the experiments) settled faster than those with inclined orientation (48%), and horizontally oriented fibers (33%) settled with the smallest velocities.Convective mixing of water, heated from below, principally changed the manner of sinking of fibers: their motions became unsteady and 3-dimensional. In 78 measurements for 4-mm long nylon fibers (using the “light knife” technique), only about 56% of fibers showed downward velocity component (mean 1.33 ± 0.78 mm/s), which was twice as small as in still water, however the ratio of max/min values increased up to 14. Fibers could move in different directions and follow circular motions of a convective cell. Our findings suggest two possible mechanisms retaining fibers in the water column: entrainment of some particles in horizontal and vertical motions and slowed sinking due to unsteady flow around the fiber. The retention of fibers leads to decrease in integral downward particle flux (up to 4 times in our experiments).

This study reports the shapes, dimensional classes, types and counts of microplastics (MPs) found in 23 individuals of N. norvegicus collected from two wild populations of the Adriatic Sea (Mediterranean basin). The focus was on three different anatomical compartments (gut, hepatopancreas and tail), which were analysed separately. MPs were found in all the investigated individuals with an average of about 17 MPs/individual. Fragments were predominant over fibers with a ratio of about 3:1. The majority of MPs were in the dimensional range 50–100 μm. The predominant polymers were polyester, polyamide 6, polyvinyl chloride and polyethylene, which together constitute about 61% of all the MPs found. Fragments were more concentrated in the hepatopancreas, with no significant difference between gut and tail, while fibers were more concentrated in the gut than in the tail with hepatopancreas somehow in between. The dimensional class of the MPs influences their anatomical distribution. There were no statistical differences among individuals from the two sampling sites. Sex of the individual did not influence the level of retained MPs, while length had a very marginal effect. The information reported here contributes to understanding of the possible risks linked to human consumption of different tissues from contaminated Norway lobsters.

Plastics in the oceans can break up into smaller size and shape resembling prey or particles selected for ingestion by marine organisms. Plastic polymers may contain chemical additives and contaminants, including known endocrine disruptors that may be harmful for the marine organisms, in turn posing potential risks to marine ecosystems, biodiversity and food availability.This study assesses the presence of plastics in the contents of the gastrointestinal tract (GIT) of a commercial fish species, the Atlantic horse mackerel, Trachurus trachurus, sampled from two different fishing areas of central Mediterranean Sea. Adverse effect of plastics occurrence on T. Trachurus health were also assessed quantifying the liver expression of vitellogenin (VTG), a biomarker for endocrine disruption.A total of 92 specimens were collected and morphometric indices were analysed. A subgroup was examined for microplastics (MP < 1 mm) and macroplastics (MaP >1 cm) accumulation in the GIT and for VTG expression.Results indicated that specimens from the two locations are different in size and maturity but the ingestion of plastic is widespread, with microplastics (fragments and filaments) abundantly present in nearly all samples while macroplastics were found in the larger specimens, collected in one of the two locations. Spectroscopic analysis revealed that the most abundant polymers in MP fragments were polystyrene, polyethylene and polypropylene, whereas MP filaments were identified mainly as nylon 6, acrylic and polyester. MaP were composed mainly of weathered polyethylene or polypropylene.The expression of VTG was observed in the liver of 60% of all male specimens from both locations.The results of this study represent a first evidence that the ingestion of plastic pollution may alter endocrine system function in adult fish T. Trachurus and warrants further research.

The aim of the present study was to evaluate “flushable” and “non-flushable” wet wipes as a source of plastic pollution in the River Thames at Hammersmith, London and the impacts they have on the invasive Asian clam, Corbicula fluminea, in this watercourse. Surveys were conducted to assess whether the density of wet wipes along the foreshore upstream of Hammersmith Bridge affected the distribution of C. fluminea. High densities of wet wipes were associated with low numbers of clams and vice versa. The maximum wet wipe density recorded was 143 wipes m⁻² and maximum clam density 151 individuals m⁻². Clams adjacent to the wet wipe reefs were found to contain synthetic polymers including polypropylene (57%), polyethylene (9%), polyallomer (8%), nylon (8%) and polyester (3%). Some of these polymers may have originated from the wet wipe reefs.

A better understanding of the sources of organophosphate esters (OPEs) is a prerequisite for OPE control and the establishment of related environmental policies. Sources of OPEs in 35 major inflow rivers to the Bohai Sea of China were quantitatively analyzed using three effective receptor models (principal component analysis-multiple linear regression (PCA-MLR), positive matrix factorization (PMF), and Unmix) in this paper. The similarities and differences in results from PCA-MLR, PMF, and Unmix were discussed in depth. All three models well predicted the spatial variability of the total concentrations of nine OPEs (triethyl phosphate, tri-n-butyl phosphate, triisobutyl phosphate, tri (2-ethylhexyl) phosphate, tri (2-chloroethyl) phosphate, tris(1-chloro-2-propyl) phosphate, tris(1,3-dichloro-2-propyl) phosphate, triphenyl phosphate, and triphenylphosphine oxide) (∑₉OPEs) (r² = 0.90–0.96, p = 0.000) and explained 98.4%–101.2% of the observed ∑₉OPEs. The predicted ∑₉OPEs values from each pairwise model were significantly correlated (r² = 0.88–0.91, p = 0.000). Three OPE sources were extracted by all three models: rigid and flexible polyurethane foam/coating, cellulosic/acrylic/vinyl polymer/unsaturated polyester, and polyvinyl chloride, contributing 49.9%, 29.7%, and 20.5% by PCA-MLR, 57.9%, 28.6%, and 13.5% by PMF, and 47.9%, 30.8%, and 22.4% by Unmix to the ∑₉OPEs, respectively. PMF was recommended as the preferred receptor model for analyzing OPE sources in water during the monitoring period because of its optimal performance.

Microplastics have become an inevitable component of our environment. Worldwide, free public fountains are common and one of the best sources of drinking water which are being installed with one of the viewpoints of reducing single-use plastics bottle consumption. However, the state of knowledge on how microplastics might be affecting in those free public drinking fountains is unknown. In this study, free drinking water fountains from 42 metro stations in Mexico City were being looked into for the occurrence of microplastics and investigated their shape type, size, abundance, distribution, polymer composition and surface morphology. Microplastics were detected in all the samples analyzed. The results revealed the significant abundance of microplastics ranging from 5 ± 2 to 91 ± 14 L⁻¹ in drinking water with an overall average of 18 ± 7 microplastics L⁻¹. Transparent fibers (69%) were predominant in the identified microplastics followed by blue (24%) and red colored (7%) fibers. The most frequent microplastics dimensions ranged between 0.1 and 1 mm which is approximately 75% of the total microplastics. Micro-Raman spectroscopy analysis indicated that microplastics contained in drinking water were mainly polyesters (poly (trimethylene terephthalate)) and epoxy resin suggesting the possible contribution of wastewater discharges for microplastics contamination. Thus, this study findings show that free public drinking water fountains are potential microplastics hotspot for human consumption and provide useful references for mitigation measures.