Brewing plastics: OCT reveals microplastic release from nylon tea bags in simulated brewed tea infusions.

Small-sized microplastics (MPs) pose concerns about potential risks to both the environment and human health. However, research on MP pollution is hampered by limitations in the detection techniques. Also, few studies have provided insight into the release of small-sized MPs from disposable polyethylene terephthalate (PET)-bottled drinks for outdoor usage. Thus, PET bottles’ potential to release small MPs sized 1–100 μm outdoors was studied in relation to physical and chemical parameters (temperature, sunlight irradiation, and drink characteristics) using flow cytometry and Nile Red dye. The results showed that temperatures below 80 °C had little effect on the release of MPs from PET bottles. Sunlight irradiation and alkalinity were prone to promote the generation of MPs, mostly 1–5 μm in size. Moreover, the combined impact test implied that two pairings—acidity with temperature and alkalinity with sunlight—positively affected MP release, with maximum releases of 21,622 ± 2477 particles/L and 31,081 ± 7173 particles/L, respectively. Based on the rapid quantification of small-sized MPs using flow cytometry after Nile Red selection, the results hereby presented will assist researchers in reducing MP release and aid them in the evaluation of MPs’ contamination of aquatic environments.

Microplastics (MP) are the plastics with 1 μm-5 mm dimensions. Meanwhile, compost has been identified as a major source of MP in the soil, although compost is a great plant nutrient source, and it provides tremendous benefits for crops. This is primarily ascribed to most of the compost being produced through Municipal Solid Waste Management projects. However, due to the detrimental impacts on soil’s biological, physical, and chemical health, together with the high accumulation probability of MP caused by repeated application of compost, regulations should be implemented on the limitation of MP in compost. Even though there are a few different methods available in the literature for MP extraction and quantification in organic matter (OM)-rich matrices, like compost, sludge, and sediments, a properly validated, routine analytical procedure is missing in Sri Lanka Standards (SLS). Therefore, in this project, the effectiveness of four different MP extraction methods in the literature were compared and validated for compost, to implement an MP analysis method suitable for compost specifications in the SLS. The methodologies included MP extraction by density separation using NaCl or ZnCl2 solutions followed by digestion of OM using 30% KOH: NaOCl solution or Fenton’s reagent. The common MP analysis method for the four protocols was staining with the hydrophobic, fluorescent stain Nile Red, and visual observation. Digestion efficiency of OM and spike recovery of Polystyrene (PS), Polyvinyl Chloride (PVC), Polyethylene terephthalate (PET), High-Density Polyethylene (HDPE), and Polypropylene (PP) microplastics in 1-2 mm dimension by the four MP extraction methods were compared for the validation. T-tests (confidence level=95%) were carried out to determine the significant difference between the OM digestion efficiency in each of the four methods. Each of the combinations compared was significantly different from the other except for ZnCl2/Fenton and NaCl/30% KOH:NaOCl comparison. Meanwhile, the OM removal by ZnCl2/Fenton and NaCl/30% KOH:NaOCl excluding the density separation step also was not significantly different. The spike recovery analysis showed ZnCl2/Fenton combination as the best out of the tested combinations with above 95% recovery percentages for PS, PVC, PP and 100 for HDPE and PET by particle count. However, precipitate formations in the ZnCl2/Fenton combination might cause false negative or positive results for spike recovery when applied to the real samples with smaller MP. The extraction reagents, NaCl was not an ideal solution and ZnCl2 was a good solution for the MP types used. Moreover, in this project, double digestion of OM with NaCl/30% KOH:NaOCl before and after the density separation with ZnCl2 is suggested as a novel and more effective OM digestion protocol before Nile Red staining, and further validations are suggested prior to its final implementation.
 
 Keywords: Microplastics, Compost, Extraction, Organic matter

The current study aimed to investigate the release of microplastics (MPs) into commercially packaged mango and pineapple juices stored at 4 and 25°C for 180 d (0, 1, 7, 14, 28, and 180 d). The samples were digested with H2O2, filtered, and analysed by optical microscope in terms of abundance, size, colour, and shape. Then, MPs were then fixed on adhesive copper tape, and polymer type was detected using confocal Raman spectroscopy. Also, the MPs surface morphology and chemical composition were analysed by SEM-EDX. Thereafter, the estimated daily intake (EDI) of MPs by juice consumption was estimated. MP abundance increased significantly with storage time and temperature. After 180 d, concentrations of MPs in mango and pineapple juice were 13.65 ± 0.45 and 16.55 ± 0.35 MPs particles/50 mL at 4°C, and 18.75 ± 0.51 and 19.68 ± 0.42 MPs particles/50 mL at 25°C, respectively. Raman spectroscopy confirmed the polymers polystyrene, polypropylene, polycarbonate, and polyamide. After 180 d of storage, the Estimated Daily Intake (EDI) of MPs for adults ranged from 0.117 to 0.169 particles/kg/day, with the highest values from juice stored at 25°C (mango: 0.161 and pineapple: 0.169 particles/kg/d), while for children, EDI values were higher, ranging from 0.447 to 0.645 particles/kg/d across both juices and storage temperatures. These findings demonstrate that extended storage and higher temperature significantly enhance MP release, directly influencing consumer exposure levels and highlighting the need for storage-aware risk assessments of beverage packaging.

The pervasive and growing contamination of ecosystems by microplastics (MPs) has emerged as a critical environmental and societal challenge. These synthetic polymer fragments, typically defined as plastic particles smaller than 5 mm, are now recognized not only for their persistence in natural environments but also for their potential to carry adsorbed pollutants and to be ingested by a wide range of organisms, including humans. Of particular concern are MPs in the sub-100 μm range, which are more difficult to isolate and analyze but may exhibit enhanced mobility, reactivity, and bioavailability. The accurate detection, quantification, and chemical characterization of such small MPs are therefore essential for advancing our understanding of their sources, fate, and impacts. However, current analytical approaches—primarily based on filtration, staining, and spectroscopic methods—remain time-consuming and often lack the sensitivity or selectivity required for sub-100 μm particles in complex aqueous matrices. In this study, we present a novel microfluidic strategy for the rapid, in-flow detection and molecular identification of individual MPs in suspension. The method integrates dielectrophoresis (DEP) for the label-free spatial manipulation of particles and Raman microspectroscopy (RM) for their chemical fingerprinting. A custom-fabricated glass microfluidic chip was developed, incorporating electrodes on both the top and bottom surfaces of the main channel to achieve three-dimensional DEP focusing. MPs ranging from 25 to 50 μm in diameter were successfully aligned along the channel's central axis and interrogated in real time using RM. This approach enabled unambiguous, particle-by-particle identification of five widely encountered polymer types: polystyrene (PS), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), and polyethylene terephthalate (PET), both in monodisperse and polydisperse mixtures. Our results demonstrate that DEP/RM coupling offers a powerful and scalable platform for in-flow MPs analysis, combining high spatial resolution and chemical specificity. This proof of concept opens new possibilities for high-throughput and automated detection of MPs in environmental monitoring and water analysis.

The current work presents a Novel, Carbon Dot fluoroprobe to selectively identify and quantify Microplastics (MPs) released from Surgical facemask and Cosmetic Personal Cleansers. Solid Fluorescent Green Carbon Dots (SFGCDs) are synthesized for the first time from a high carbon source natural resin, obtained from Araucaria araucana (Monkey puzzle tree). The increased carbon content is responsible for the green colour of the CDs. SFGCDs function as a TURN OFF fluoroprobe on detection of MPs through dynamic quenching mechanism, which is confirmed from Stern Volmer Plot with an R2 value of. The minimum LOD being 0.0063g/l for ≥ 6μm diameter MPs. The agglomeration of microplastics released from surgical mask and cosmetic cleansers on functions as an insulator on the surface of SFGCDs, forbidding ease of electron- hole transfer between the donor- SFGCDs and acceptor-MPs. The release of MPs from the donor surface results in reappearance of fluorescence obeying FRET mechanism. The detection of MPs/ microfibres released by disposable surgical mask is studied by the degradation of the surgical face mask for a period of 50days, followed by detection. Turn- OFF in fluorescence of SFGCDs observed in presence of micro fibre Turns On, as remediation of MPs is done by a simple filtration technique. The results demonstrate the potential of the fluoroprobe towards real time detection of MPs and simple remediation of MPs to conserve the ecosystem. The SFGCDs is stable and can be reused for nearly 3 cycles for the detection of MPs. A single PL peak obtained on detection of MPs in presence of monovalent, divalent trivalent ions and biomolecules authenticates the selectivity and stability of SFGCDs to function as an efficient fluoroprobe towards sensing of MPs.

How to detect small microplastics (20–100 μm) in freshwater, municipal wastewaters and landfill leachates? A trial from sampling to identification

Synthetic polymers are widely used in medical devices and implants where biocompatibility and mechanical strength are key enablers of emerging technologies. One concern that has not been widely studied is the potential of their microplastics (MPs) release. Here we studied the levels of MP debris released following 8-week in vitro tests on three typical polyglycolic acid (PGA) based absorbable sutures (PGA 100, PGA 90 and PGA 75) and two nonabsorbable sutures (polypropylene-PP and polyamide-PA) in simulated body fluid. The MP release levels ranked from PGA 100 > > PGA 90 > PGA 75 > > PP ∼ PA. A typical PGA 100 suture released 0.63 ± 0.087 million micro (MPs > 1 µm) and 1.96 ± 0.04 million nano (NPs, 200–1000 nm) plastic particles per centimeter. In contrast, no MPs were released from the nonabsorbable sutures under the same conditions. PGA that was co-blended with 10–25% L-lactide or epsilon-caprolactone resulted in a two orders of magnitude lower level of MP release. These results underscore the need to assess the release of nano- and microplastics from medical polymers while applied in the human body and to evaluate possible risks to human health.

Fluorescence microscopy is increasingly seen as a fast, user-friendly, and high-throughput method for detecting microplastics (MPs) in soil; however, its effectiveness across diverse MP types and soil properties remains underexplored. This study tested a fluorescence microscopy–Nile red (NR) staining approach on eight MP types, covering both biodegradable and non-biodegradable plastics, in three size ranges (≤ 150 µm, 100–250 µm, 500–1000 µm) across loamy, clayey, and sandy soils. Each sample, processed in triplicate, underwent a relatively quick and straightforward extraction procedure involving density separation, organic digestion, and NR staining, followed by fluorescence and bright-field microscopy. A new digital image analysis pipeline using Image J was developed to expedite and (semi)automate MP quantification. Recoveries ranged from 80% to 90% for MPs with a Feret diameter of 500–1000 µm, regardless of soil type. In contrast, the recovery of smaller MPs (Feret dia. ≤ 250 µm) varied depending on the soils and plastic types: recoveries for low-density polyethylene (LDPE) reached 85% in sandy soil and 90% in loamy soil, whereas those for biodegradable polybutylene adipate terephthalate/polylactic acid (PBAT/PLA) were only 60% and 10%, respectively. The lowest recovery rate was observed in clayey soil and for biodegradable plastics. The method was tested on non-agricultural soil samples, yielding a MP mean number concentration of 20.7 ± 9.0 MPs/g for MPs sized from dia. ≥ 25 µm, comparable to Fourier transform infrared (FPA-µ-FTIR) results of 13.1 ± 7.3 MPs/g (p > 0.05). We conclude that fluorescence microscopy with NR staining and automated particle quantification offers a time-efficient, reproducible, and accurate method for MP detection in light-textured soils, whereas limitations remain for reliable MP analysis in clay-dominated soils.Graphical

Plastic pollutioncan pose a threat to birds. Yet, littleis knownabout the sublethal effects of ingested microplastics (MP), and theeffects of MP < 1 mm in birds remain unknown. This study thereforeaimed at evaluating the toxicity of environmentally relevant polypropyleneand polyethylene particles collected in the Norwegian coast in growingJapanese quail (Coturnix japonica).Birds were orally exposed to 600 mg MP over 5 weeks, covering small(<125 μm) and large (3 mm) MP, both separately and in a mixture.We evaluated multiple sublethal endpoints in quail, including oxidativestress, cytokine levels, blood-biochemical parameters, and reproductivehormones in blood, as well as body mass. Exposure to small MP significantlyinduced the activities of the antioxidant enzymes catalase, glutathione-S-transferase,and glutathione peroxidase. Exposure to large MP increased the levelsof aspartate aminotransferase (liver parameter) and decreased 17β-estradiollevels in females. Body mass was not directly affected by MP ingestion;however, quail exposed to small MP and a mixture of large and smallMP had a different growth rate compared to control quail. Our studyused similar levels of MP as ingested by wild birds and demonstratedsize-dependent effects of MP that can result in sublethal effectsin avifauna.

Nile Red (NR) fluorescence is an emerging method for microplastics (MPs) detection due to its efficiency in distinguishing MPs from non-plastic materials. However, drawbacks to the use of NR include plastics that cannot be stained, whereas others show changes in physical and chemical characteristics at higher NR concentrations. As a practical approach, this study optimizes MP staining concentration combining NR fluorescence (approx. 170 million a.u.) in an inexpensive stereomicroscope adaptation with UV-LED at an excitation wavelength of 365 nm. The effects of NR staining concentration were then measured in terms of polymer recovery, polymer surface area, fluorescence intensity, and infrared spectra. Our findings revealed that the tested stain concentrations did not significantly alter MP recovery counts and surface area. At 10 μg/mL NR concentration, only polyethylene terephthalate (PET) and polystyrene (PS) fluoresced, indicating polypropylene’s (PP) resistance to NR staining. The potential functional groups involved in the excitation are mainly alkenes (for PET, PS, and PP) and aldehydes (for PET), as confirmed by the FTIR analysis that could be attributed to polymer structural rearrangement, aggregation, or depolymerization. This study also demonstrates that NR staining, when paired with an adapted stereomicroscope, can be effectively used to detect and quantify MPs in sardines (Sardinella lemuru)

Wastewater treatment plants (WWTPs) are routes through which microplastics (MPs) enter the environment. This research assesses MP occurrence in 2 urban and 5 industrial WWTPs, in a city of 1.6 M inhabitants (Tabriz, Iran). The sampling schedule helps quantify the city’s MP release into surface water. One of the urban WWTPs in the study used tertiary treatment, whereas the rest of the plants only had primary and secondary treatments. MPs were not efficiently removed in the urban WWTPs: 255 ± 55 MP/L (influent) and 240 ± 50 MPs/L (effluent). In the industrial WWTPs, there was some elimination of MPs: 246 ± 169 MP/L (influent) and 94 ± 72 MPs/L (effluent). The lowest MP removal, < 10%, corresponds to urban treatment. The influents had > 1–5 mm MP particles at 14% of the total MPs in the incoming sewage, and such fraction was just < 2% of the total MPs in the effluents. In contrast, smaller MPs, especially those < 250 μm (the smallest detectable and confirmed MP was 50 μm), were the most abundant MP fraction in the treated effluents. Fibres, black MPs and particles ranging from 100 μm to < 250 μm prevailed in influents and effluents of both urban and industrial WWTPs. In the wastewater of both types of plants, the MPs were mainly composed of polyamide and polycarbonate. This research confirms that urban and industrial wastewater are important MP contributors to receiving water and calls for improvements in wastewater treatments to decrease the uncontrolled entry of MPs into the environment.

This study comprehensively investigated the abundance, morphologies, and polymer types of plastics, larger (1-5mm) and smaller (< 1mm) microplastics (MPs), in organic fertilizers using spectroscopic and microscopic methods. MPs abundance varied depending on the type of waste employed. MPs were detected in 80% of the investigated compost samples, while macro/meso plastics were found in only four samples. Compost from mixed municipal solid waste exhibited the highest MPs contamination (23100 ± 3615 items/kg dry weight), whereas compost produced from canteen waste had the lowest contamination (100 ± 65 items/kg dry weight). Smaller MPs were dominant in all samples. The estimated loads of MPs introduced into agricultural soil exceeded the previous studies. Common morphologies observed were sheet, film, fragment, and fiber, while dominant polymer types were polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), and polystyrene (PS). Heavy metals, including Cr, Cu, Ni, and Pb, were identified in association with MPs. Results indicate that the utilization of appropriate waste for composting and upgrading fertilizer regulations is crucial to protect the environment and human health from smaller MPs.

The glowing potential of Nile red for microplastics Identification: Science and mechanism of fluorescence staining

Human exposure to microplastics (MPs) through drinking water has drawn serious concern recently because of the potential adverse health effects. Although there are reports on the occurrence of MPs in bottled water, little is known about the abundance of a whole spectrum of MPs with sizes ranging from 1 µm to 5 mm due to the restrictions of conventional MPs detection methods. Some studies using micro-Raman spectroscopy can achieve MPs with a size of <10 µm, however, quantitation of all MPs was extremely time consuming and only a small portion (<10%) of MPs would be analyzed. The present study quantified MPs from nine brands of bottled water using fluorescence microscopy and flow cytometry for MPs with a size of ≥50 µm and a size of <50 µm, respectively. The average abundance of MPs with a size of ≥50 µm in bottled water samples was found ranging from 8–50 particles L−1, while MPs with a size of <50 µm were found to be 1570–17,817 particles L−1, where the MPs abundance from mineral water samples were significantly more than distilled and spring water samples. The modal size and shape of MPs were found at 1 µm and fragments, respectively. Besides, three tap water samples obtained locally were analyzed and compared with the bottled water samples, where less MPs were found in tap water samples. In addition, contamination of MPs from bottle and cap and interference by addition of mineral salts were studied, where no significant difference from all these processes to the control sample was found, suggesting the major contamination of MPs was from other manufacturing processes. Estimated daily intake (EDI) of MPs increased substantially when data of small MPs are included, suggesting that previously reports on exposure of MPs from drinking water might be underestimated, as only large MPs were considered.

The influence of drinking water constituents on the level of microplastic release from plastic kettles