1. Microplastics in groundwater: pathways, occurrence, and monitoring challengesElvira Colmenarejo Calero, Manca Kovač Viršek, Nina Mali, 2024, izvirni znanstveni članek Povzetek: Microplastics (MPs), defined as plastic particles measuring less than 5 mm, are considered an emerging pollutant. Their presence in the water cycle and their interaction with ecological processes pose a significant environmental threat. As groundwater (GW) represents the primary source of drinking water, monitoring MPs in GW and investigating their potential sources and pathways is of urgent importance. This article offers a comprehensive overview of the primary contamination pathways of MPs from surface water, seawater, and soil into the GW. Moreover, it presents an examination of the occurrence of MPs in GW and identifies the challenges associated with their monitoring in GW. This study also discusses the difficulties associated with comparing research results related to MPs in GW, as well as indicating the need for implementing standardised techniques for their sampling and detection. On the basis of our experience and the literature review, we highlight the importance of understanding the specific hydrogeological and hydrogeographic conditions, collecting representative samples, using sampling devices with comparable specifications and comparable laboratory techniques for MP identification, and preventing contamination at all stages of the monitoring process. This review offers valuable insights and practical guidelines on how to improve the reliability and comparability of results between studies monitoring MPs in GW.
Ključne besede: microplastics, groundwater, sampling, monitoring, aquifer, borehole
Objavljeno v DiRROS: 15.05.2024; Ogledov: 16; Prenosov: 3
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2. Weathering effects on cellulose acetate microplastics from discarded cigarette buttsBranka Mušič, Andrijana Sever Škapin, 2024, objavljeni znanstveni prispevek na konferenci (vabljeno predavanje) Povzetek: Cellulose acetate, commonly used in cigarette filters, poses environmental concerns due to its questionable (bio)degradability and prevalent presence in nature. This study compares the weathering effects on two types of cigarette filters: traditional and newer filters used in heated tobacco devices (HTP). Microplastics were derived from used cigarette parts and then subjected to artificial aging. Analytical techniques (Thermogravimetry-Differential Scanning Calorimetry TG/DSC, Fourier-Transform Infrared Spectroscopic Analysis (FTIR)) and loose bulk density measurements were employed pre- and post-aging cellulose acetate of both types of samples. Despite increasing evidence influencing European Union (EU) directives on tobacco product disposal, there's a lack of systematic analysis on the weathering impact, especially concerning the touted environmental benefits of newer filters. Results indicate decreased particle size in cellulose acetate filters post-aging. Variances were observed in thermal behavior, yet FTIR spectra remained unchanged.
Ključne besede: cellulose acetate, cigarette filters, microplastics, artificial weathering, polymer degradation
Objavljeno v DiRROS: 12.03.2024; Ogledov: 158; Prenosov: 159
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3. UV light causes structural changes in microplastics exposed in bio-solidsS. S. Alavian Petroody, Seyed Hossein Hashemi, Luka Škrlep, Branka Mušič, Cornelis A. M. van Gestel, Andrijana Sever Škapin, 2023, izvirni znanstveni članek Povzetek: Bio-solids (biological sludge) from wastewater treatment plants are a significant source of the emission of microplastics (MPs) into the environment. Weakening the structure of MPs before they enter the environment may accelerate their degradation and reduce the environmental exposure time. Therefore, we studied the effect of UV-A and UV-C, applied at 70 °C, on three types of MPs, polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET), that are commonly found in sewage sludge, using three shapes (fibers, lines, granules). The MPs were exposed to UV radiation in bio-solid suspensions, and to air and water as control. The structural changes in and degradation of the MPs were investigated using Attenuated Total Reflectance–Fourier Transform Infrared Spectrometry (ATR-FTIR) and surface morphology was performed with SEM analysis. UV exposure led to the emergence of carbonyl and hydroxyl groups in all of the PP samples. In PE and PET, these groups were formed only in the bio-solid suspensions. The presence of carbonyl and hydroxyl groups increased with an increasing exposure time. Overall, UV radiation had the greatest impact on the MPs in the bio-solids suspension. Due to the surface-to-volume ratio of the tested samples, which influences the degradation rate, the fibers were more degraded than the other two plastic shapes. UV-A was slightly more effective at degrading the MPs than UV-C. These findings show that ultraviolet radiation in combination with an elevated temperature affects the structure of polymers in wastewater bio-solids, which can accelerate their degradation.
Ključne besede: microplastics, degradation, hydroxyl, carbonyl, ultraviolet light
Objavljeno v DiRROS: 14.11.2023; Ogledov: 338; Prenosov: 169
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4. Textile industry as a major source of microplastics in the environmentBranka Mušič, 2023, pregledni znanstveni članek Povzetek: This review brings together data on the impact of (micro)plastics, on the environment. Critically evaluates studies on the use of various techniques for recycling textile plastic, which is a major polluter of the environment. In this review, let’s focus a bit more on industrial waste in the textile industry since it would be easiest possible to capture and recycle it again. We also discuss LCA studies, bottlenecks, and future perspectives, for a lower impact on the environment. The main challenges which make further recycling progress difficult are discussed, such as the lamination of textile fibers with metal, new textile fibers that appear as a result of rapid development, the difference in the density of textile fibers, low recycling efficiency, etc. Finally, the possible uses of more environmentally friendly polymers are shown, which can be an alternative to the current synthetic polymers. The results of the literature review showed that for the development of a sustainable textile industry, which would mitigate the impact of microplastics on the environment, from a long-term perspective, the integration of more intensive, complex decisions into the business models of manufacturing companies is necessary. The environmental consequences will be even more intense due to the massive releases of textile microfibers into the environment and excessive accumulation, therefore, in order to achieve the specific goals of sustainable development, a reduction in the production of microplastics is first required, which is only possible with a global partnership of all countries to achieve a specific goal on a global level.
Ključne besede: textile plastics, microplastics, environment, industrial textile waste, LCA, synthetic polymers alternative, recycling techniques
Objavljeno v DiRROS: 05.09.2023; Ogledov: 285; Prenosov: 164
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5. Influence of weathering on the degradation of cellulose acetate microplastics obtained from used cigarette buttsBranka Mušič, Anita Jemec Kokalj, Andrijana Sever Škapin, 2023, izvirni znanstveni članek Povzetek: Cellulose acetate is used in many applications, including for cigarette filters. Unfortunately, unlike cellulose, its (bio)degradability is under question, yet it often ends up uncontrolled in the natural environment. The main purpose of this study is to compare the effects of weathering on two types of cigarette filter (classic filters and newer filters that have more recently arrived on the market) following their use and disposal in nature. Microplastics were prepared from polymer parts of used (classic and heated tobacco products—HTP) cigarettes and artificially aged. TG/DTA, FTIR, and SEM analyses were performed both before and after the aging process. Newer tobacco products contain an additional film made of a poly(lactic acid) polymer which, like cellulose acetate, burdens the environment and poses a risk to the ecosystem. Numerous studies have been conducted on the disposal and recycling of cigarette butts and cigarette butt extracts, revealing alarming data that have also influenced the decisions of the EU, who addressed the disposal of tobacco products in the EU Directive (EU) 2019/904. Despite this, there is still no systematic analysis in the literature evaluating the impact of weathering (i.e., accelerated aging) on the degradation of cellulose acetate in classic cigarettes compared with that in newer tobacco products that have recently appeared on the market. This is of particular interest given that the latter have been promoted as being healthier and environmentally friendly. The results show that in cellulose acetate cigarette filters the particle size decreased after accelerated aging. Also, the thermal analysis revealed differences in the behavior of the aged samples, while the FTIR spectra showed no shifts in the position of the peaks. Organic substances break down under UV light, which can be seen by measuring the color change. The PLA film was found to be more stable than cellulose acetate under the influence of UV light.
Ključne besede: cellulose acetate, cigarette filters, microplastics, artificial weathering, polymer degradation
Objavljeno v DiRROS: 30.06.2023; Ogledov: 380; Prenosov: 231
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6. Environmental hazard of polypropylene microplastics from disposable medical masks : acute toxicity towards Daphnia magna and current knowledge on other polypropylene microplasticsAnita Jemec Kokalj, Andraž Dolar, Damjana Drobne, Marjan Marinšek, Matej Dolenec, Luka Škrlep, Gregor Strmljan, Branka Mušič, Andrijana Sever Škapin, 2022, izvirni znanstveni članek Povzetek: The COVID-19 pandemic has increased the use of disposable plastics, including medical masks, which have become a necessity in our daily lives. As these are often improperly disposed of, they represent an important potential source of microplastics in the environment. We prepared microplastics from polypropylene medical masks and characterised their size, shape, organic chemical leaching, and acute toxicity to the planktonic crustacean Daphnia magna. The three layers of the masks were separately milled and characterised. Each of the inner frontal, middle filtering, and outer layers yielded different types of microplastics: fibres were obtained from the inner and outer layer, but irregular fragments from the middle layer. The shape of the obtained microplastics differed from the initial fibrous structure of the intact medical mask layers, which indicates that the material is deformed during cryo-milling. The chemical compositions of plastics-associated chemicals also varied between the different layers. Typically, the inner layer contained more chemicals related to antimicrobial function and flavouring. The other two layers also contained antioxidants and their degradation products, plasticisers, cross-linking agents, antistatic agents, lubricants, and non-ionic surfactants. An acute study with D. magna showed that these microplastics do not cause immobility but do physically interact with the daphnids. Further long-term studies with these microplastics are needed using a suite of test organisms. Indeed, studies with other polypropylene microplastics have shown numerous adverse effects on other organisms at concentrations that have already been reported in the environment. Further efforts should be made to investigate the environmental hazards of polypropylene microplastics from medical masks and how to handle this new source of environmental burden.
Ključne besede: COVID-19 pandemic, plastics-associated chemicals, Daphnia magna, fibres, fragments, nanofibres, polypropylene microplastics, single-use plastic
Objavljeno v DiRROS: 05.05.2023; Ogledov: 367; Prenosov: 226
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7. Magnetic extraction of weathered tire wear particles and polyethylene microplasticsVaibhav Budhiraja, Branka Mušič, Andrej Kržan, 2022, izvirni znanstveni članek Povzetek: Magnetic extraction offers a rapid and low-cost solution to microplastic (MP) separation, in which we magnetize the hydrophobic surface of MPs to separate them from complex environmental matrices using magnets. We synthesized a hydrophobic Fe-silane based nanocomposite (Fe@SiO2/MDOS) to separate MPs from freshwater. Pristine and weathered, polyethylene (PE) and tire wear particles (TWP) of different sizes were used in the study. The weathering of MPs was performed in an accelerated weathering chamber according to ISO 4892-2:2013 standards that mimic natural weathering conditions. The chemical properties and morphology of the Fe@SiO2/MDOS, PE and TWP were confirmed by Fourier transform infrared spectroscopy and Scanning electron microscopy, respectively. The thermal properties of PE and TWP were evaluated by Thermogravimetric analysis. Using 1.00 mg of Fe@SiO2/MDOS nanocomposite, 2.00 mg of pristine and weathered PE were extracted from freshwater; whereas, using the same amount of the nanocomposite, 7.92 mg of pristine TWP and 6.87 mg of weathered TWP were extracted. The retrieval of weathered TWP was 13% less than that of pristine TWP, which can be attributed to the increasing hydrophilicity of weathered TWP. The results reveal that the effectiveness of the magnetic separation technique varies among different polymer types and their sizes; the weathering of MPs also influences the magnetic separation efficiency.
Ključne besede: degradation, magnetic separation, microplastics, polyethylene, tire wear particles, open access
Objavljeno v DiRROS: 03.05.2023; Ogledov: 448; Prenosov: 373
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