Cigarette filters as a main microfibers source in aquatic environments: Phase I

Cigarette filters as a main microfibers source in aquatic environments: Phase I | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Cigarette filters as a main microfibers source in aquatic environments: Phase I Azam Mohammadi, Farkhondeh Bahrani, Gabriel Enrique De-la-Torre, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6860318/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 22 Oct, 2025 Read the published version in Scientific Reports → Version 1 posted 10 You are reading this latest preprint version Abstract Cigarette butts (CBs) are known as one of the most prevalent forms of environmental waste, needing global attention to mitigate their detrimental health and ecological impacts. Owing to their filter composition, discarded CBs can persistently release microfibers (MFs) into the environment. In this research, the levels, characteristics, and ecological risks associated with MFs released from cigarette filters (CFs) into water (distilled and seawater) were investigated under various environmental conditions (laboratory and outdoor settings). The assessment focused on short-term exposure durations of 1, 2, 7, 15, 30, and 60 days, forming the initial phase of this research. The mean level of released MFs ranged from 5.78-92.43 items/g CFs. The results highlighted that more MFs were released from CFs into the seawater and outdoor environment at a contact time of 60 days. The predominant size and color of the released MFs were 20-50 µm and white/transparent, respectively. The main detected polymer composition of MFs was cellulose acetate. The computed pollution load index (PLI) values were > 30, indicating severe pollution. Additionally, the risk quotient (RQ) values were greater than 1, indicating a potential threat to the water environment. Based on mean levels of released MFs through CFs during contact times of 1 to 60 days and the amount of discarded CBs yearly on a global scale, CFs can leachate14×10 12 -51×10 12 MFs into the aquatic environments. The results of present research allow scientific society to better comprehend the CFs' role in transporting MFs in the aquatic systems as well as their potential environmental risks. Earth and environmental sciences/Environmental sciences Physical sciences/Chemistry Cellulose acetate Cigarette butt Contamination Marine environment Microplastics Risk assessment. Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 1. Introduction Plastic contamination is recently attracted significant consideration from the public section 1 . Microplastics (MPs) are emerging contaminants that are converting an increasing concern around the world because of their extensive incidence and harmful biological and ecological impacts 2 . MPs refer to plastic particles of 1 µm to 5 mm, differing in composition, size and shape 3 . MP particles can be classified into primary MPs manufactured for industrial use and secondary MPs produced from the breaking larger plastics 4 . Exposure of MP particles to external environmental factors, e.g., sunlight, mechanical wear, seawater, soil, and microorganisms, leads to their physical and chemical changes 5 . MPs release in the water and terrestrial environments can cause harm to living organisms 6 . Synthetic microfibers (MFs), as one of the major contaminants in the aquatic ecosystems, are secondary MPs 7 , which aquatic species may consume mistakenly 8 . Recently, a growing number of researches have been performed on the MPs presence in different environmental samples, including coastline sediment 9 , 10 , urban runoff 11 , 12 , organic solid waste 13 , 14 , landfill leachate 15 , 16 , indoor dust 17 , 18 , air 19 , 20 , and ballast water 21 , 22 . However, a limited data exists on the exact role of CFs in releasing MFs into the aquatic environment 1 . Between all the debris types identified in the environment, CBs are one of the most dominant 23 . Based on the reports, more than 5.8 trillion cigarettes are manufactured around the world annually, and more than 4.95 trillion CFs are improperly thrown away 24 . Many CFs are dumped into the streets and the environment, transferred by rain or urban runoff to other ecosystems, such as coastal and marine environments 25 . The used CFs contain different chemical contaminants 26 , which may be leached into the surrounding environment and pose serious environmental risks. These toxic chemicals may also be associated with the released MFs via CFs and be easily transported across different environmental media. The tobacco CFs generally comprise over15,000 fiber string constructed from cellulose acetate with plasticizer additives, which can take up to 30 years to degrade under special conditions 27 . Each discarded CF introduced into aquatic systems has the potential to release significant quantities of chemical compounds and MFs into the environment, posing a risk of acute toxicity to aquatic organisms 28 . Because discarded CFs as a potential source of MFs and plastic additives can cause ecological hazards, it is necessary to determine the role of CFs in releasing MFs into the environment. While the detachment rate of MFs from smoked CFs has only been investigated in a previous study at an exposure time of one month 1 , no prior research has yet reported the features of released MFs via CFs at different exposure times under different environmental condition as well as their environmental risks. Thus, the objectives of this research were to 1) Determine the levels and features (size, polymer type, and color) of released MFs via CFs into different water samples at various exposure times; 2) Compare the levels of released MFs via CFs between different brands of cigarette, water types, environment conditions, and exposure times; 3) Specify the pollution load index (PLI) and risk quotient (RQ) of released MFs via CFs into water at different exposure times; and 4) Estimate the emission rate of MFs via CFs into water bodies on a worldwide scale. 2. Methodology 2.1. Sampling and experimental setup In January 2023, 144 cigarette samples of two international cigarette brands, labeled as brand 1 and brand 2, were prepared from Bushehr, Iran, marketing. The release experiments of MFs via CFs were done in two water types [distilled water (DW) and seawater (SW)] under two different environmental conditions [lab environment (LE) without sun exposure and outdoor environment (OE) with sun exposure] at six different exposure times of 1, 2, 7, 15, 30, and 60-days. Each cigarette was cut from the filter side with a size of 3 cm by a sterile stainless-steel blade. 3 repetitions were performed for each exposure time with 3 CFs in each run. The mean CF weight (± SD) of brand 1 and brand 2 were 0.173 (± 0.002) and 0.172 (± 0.003) g, respectively (Table S1 ). For experiments, SW samples from the Persian Gulf were filtered via cellulose nitrate filter papers (Whatman, Maidstone, Kent, UK) with 0.45 µm pore-size. Also, DW (15 MΩ/cm) produced from an ELGA Purelab (Lane End, High Wycombe, UK) water purification system was applied to the experiment after filtering via filter papers with pore-size of 0.45 µm. 2.2. Release experiments of MFs The CF samples of each brand were transported to a glass beaker. The samples were exposed to four conditions: DW/in LE, DW/in OE, SW/in LE, and SW/in OE. The water (DW or SW) was added to each beaker and maintained at different desired periods of 1, 2, 7, 15, 30, and 60 days. After each contact time, each sample was vacuum-filtered. Then, each filter was placed into a petri dish and air dried. A flowchart of the experimental workflow is shown in Fig. 1 . This scheme shows 144 CF samples of two cigarette brands (72 each), investigated with different conditions at different exposure times. 2.3. Quantification and identification of MFs 2.3.1. Optical analysis All particles suspected of being MFs were examined by an optical microscope (A. KRÜSS Optronic, Germany) with a maximum 40x magnification. Then, the size and color of MFs were recorded and categorized. During visual recognition, we followed the guidelines proposed by Hidalgo-Ruz et al. (2012) study to decrease error 29 . To precise diagnose MFs from other probable crystal structures, such as salt pieces and chemical particles, a heated needle was applied in some cases. The stainless-steel probe diameter was used to measure the longest part of each MFs. 2.3.2. Raman analysis The polymer type of the extracted MFs was confirmed by a DXR3 Raman Microscope (Thermo Fisher) with a 10x magnification lens. All MF samples were placed onto prepared copper tapes for analysis, and a 785 nm laser was applied as the excitation source. The Raman spectra were obtained in the range of 400–2450 cm⁻¹. The types of MFs were identified by the obtained spectra to a reference database library for the microscope. To identify the polymer type of MFs, the obtained Raman spectra were compared with a reference database library containing common MPs observed in environmental samples 30 . The matching algorithm applied a Cauchy-Schwarz distance metric to evaluate the similarity among the measured and reference spectra. The three best hits were identified, and a threshold value of 0.4 was applied to ensure robust matches. If the hit quality index (HQI) value exceeded 0.7, the corresponding database entry was considered an identification for the MFs. More details of Raman analysis are explained in the supplementary file. 2.3.3. Scanning electron microscope coupled with an energy dispersive X-ray (SEM-EDS) analysis The elemental composition and morphology of identified MFs were investigated by a SEM-EDS (TESCAN, Czech Republic). The selected MFs samples were prepared on double sided carbon conductive tape for the analysis. Furthermore, a layer of nanometric gold was used on the particles surface to prevent sample charging and enhance the quality of observation. 2.4. Quality Assurance (QA)/Quality Control (QC) Before usage to prevent contamination during the process, all tools applied for the collection of samples and lab analysis was rinsed with DW and concealed with aluminum foil. Clean gloves, Cotton masks, and cotton laboratory coats were worn in all steps. To eliminate the particles from them, the desks surface was cleansed with paper wipes. All water applied in the experiments was filtered via a cellulose nitrate membrane filter with a pore size of 0.45 µm. Blank samples were prepared by the similar processing methods used to the lab process. Then, the mean MFs number identified in the blank samples was deducted from the findings of the experimental sets. All experiments were done in three repetitions to enhance the results reliability, and the mean levels are presented here. 2.5. Environmental risk assessment Commonly, the Pollution Load Index (PLI) is utilized to comprehensively evaluate the discharge pollution level 31 . PLI was used to estimate the overall pollution level of MFs as follows 32 : $$\:{CF}_{i}=\frac{{C}_{i}}{{C}_{oi}}$$ 1 $$\:PLI=\sqrt{{CF}_{i}}$$ 2 $$\:{PLI}_{zone}=\sqrt[n]{{PLI}_{1}\times\:{PLI}_{2}\times\:\dots\:\times\:{PLI}_{n}}\:$$ 3 Here, C i represents the mean number of MFs (items/ m 3 ) released from CFs into the water, and C oi as the background level of MP particle represents the published lowest mean number of MPs (0.71 particles/m 3 ) in the surface water 33 . PLI were divided into four groups: without or very low contamination (class I: 10 > PLI), low contamination (class II: 20 > PLI ≥ 10), moderate contamination (class III: 30 > PLI ≥ 20), and severe contamination (class IV: PLI > 30) 32 . The potential environmental risks of the identified MFs in water were evaluated by the risk quotient (RQ) technique that has been previously applied to assess the MPs risks in aquatic ecosystems. The RQ was calculated using the following formula 34 : $$\:RQ=\frac{\text{M}\text{E}\text{C}}{\text{P}\text{N}\text{E}\text{C}}$$ 4 Where MEC is the level of MFs (items/m 3 ) released from CFs into the water, PNEC is the predicted no-effect concentration below at which the organisms show negligible harmful effects. Based on the former study, The value of PNEC used was 4920 items/m³ 35 . The estimated RQ was divided into two risk levels: RQ 1 shows a high potential of environmental risk 34 . 2.5. Data analysis Levene and Shapiro-Wilks tests were applied to assess the normality and homogeneity of variances. One-way analysis of variance (ANOVA) as a parametric testing method and Tukey Post Hoc were applied to specify the differences among the MFs levels released from CFs at different exposure times. Furthermore, sample t-test analysis was applied to identify the differences among the levels of released MFs via two types of cigarette brands, waters, and environmental conditions. Statistically significant was accepted at p-value lower than 0.05. Microsoft Excel 2018 and SPSS 20 software were used to statistical analyses. 3. Results and discussions 3.1. MFs released from CBs A mean of 1.33 particles/blank (range of 0 to 2) was identified in the six blank samples of brand 1, and a mean of 1.67 particles/blank (range of 1 to 3) in the six blank samples of brand 2 at different exposure times of 1, 2, 7, 15, 30, and 60-days, respectively. Two blank samples (in the LE and OE) for each brand were investigated at each exposure time. The detected MF particles in the blank samples were deducted from the counted MFs number in the experimental samples considering size, shape, and color. MPs were found in both brands of cigarette at different exposure times. The details of released MFs via CFs into DW and SW in LE and OE conditions at different exposure times are presented in Table S2. As shown in Fig. 2 and Table S3, the mean level of released MFs at studied contact times of 1, 2, 7, 15, 30, and 60 days ranged from 5.88 to 34.77, 11.63–35.66, 11.85–47.16, 17.3–63.4, 17.66–75.9, and 30.32–92.43 items/g CFs, respectively. The time-dependent release of MFs may be related to the physical degradation of CFs 36 . The levels of MFs in the SW samples were greater compared to the DW samples at all exposure times. Significant differences (p-value 0.05) were found among the levels of MF released from different brands of cigarettes as well as the levels of MFs in two environmental conditions (Table S3). Only one study in Terrassa, Spain, investigated the levels of MFs leached from smoked CB via different cigarette brands in the laboratory environment, reporting 100 MFs per day with a size of < 0.2 mm released from every smoked cigarette in the first two weeks. As reported, three CBs without wrapping papers in each run were used to investigate the release of MFs from CBs into DW and synthetic SW. The samples were submitted to slow mechanical agitation and continuous UV light exposure for one month 1 . The higher MFs reported by Belzagui et al., 2021 compared to the current research can be due to the mechanical agitation applied in their study, which significantly enhances the detachment and breakdown of fibers. In their research, the most identified size of MFs was < 0.2 mm and the smallest and largest sizes of detected particles were not reported, while the size of MFs in the present study was in the range of 20-5000 µm. Considering the current valid methods in measuring MPs, the identified lower size (especially lower than 20 µm) is in doubt and may change the numbers of detected MFs. Thus, the different levels of MFs released from CBs and CFs can be associated with the difference in the type of cigarette (smoked or unsmoked), exposure condition, type of water, contact time, and analytical techniques used for extracting of MFs. In a previous study in Narragansett Bay, USA, the high abundance of cellulose acetate MFs in the sediments was attributed to sediment contamination with CFs 37 . The CFs are constructed of cellulose acetate, considered a semi-synthetic polymer 5 . In addition to the structural characteristics, several environmental factors, including sunlight, temperature, pH, humidity, availability of nutrients, microorganisms, and oxygen, effect on the cellulose acetate degradation rate at any particular place 38 . Exposure to solar irradiation may primarily influence on the fate of plastics and the amount of their physical and chemical degradation after disposal in the natural environment or landfills 39 . Especially, contact to UV light causes scission of chain and consequent the polymer backbone oxidation 40 . Also, UV irradiation commonly increases the plastics biodegradability by introducing polar groups and enhancement of the surface area. Although the maximum absorption for cellulose acetate is ∼260 nm, the cut off for sunlight that reaches the Earth is approximately 300 nm. This shows that natural sunlight may not considerably degrade pure cellulose acetate 5 . Also, cellulose acetate is not readily biodegradable polymer. Thus, it may remain in the environment for many years 41 . Other factors, for example water salinity and air temperature, can also affect the aging MPs process 42 . Basically, the enhancement of temperature causes the breaking MFs, especially cellulosic fibers 43 . The salinity of seawater acts an essential role in the MPs distribution and their characteristics 44 . It should be noted that the salinity affects the chemical degradation rate of MFs, including cellulose acetate 45 . The salinity of seawater causes complex changes in water properties, for example ionic strength, polarity, and pH, which can influence on the degradation of plastic debris and the release of organic plastic additives 46 . The contaminants sorption on MPs is significantly related to changes in salinity. With increasing salinity, the electrical dual layer of MPs may compact for having a greater density, and the hydration layer thickness may reduce that can help to greater absorption of contaminants on MP particles 47 . MPs and connected contaminants in the marine environment may affect organisms or enter into food chains and eventually be consumed by humans 48 . Different chemical contaminants can be adsorbed on the surface of synthetic plastic materials 9 , 49 . Plasticizers, especially phthalates, are commonly added to cellulose acetate, which can migrate into the environment and subsequently cause harmful influences on human health 50 . 3.2. Physical characteristics of MFs The size of identified MFs released via CFs was classified into six categories, as displayed in Fig. 3 and Table S4. Among the MFs leached from CFs of brand 1, 26.9% were within 20–50 µm size range, 25% within 50–100 µm size range, 23.1% within 100–250 µm, 13.1% within 250–500 µm, 6.2% within 500–1000 µm, and 5.6% within 1000–5000 µm size range. In the case of brand 2 of CFs, 29.1% of the MFs were within the size range of the 20–50 µm size, 16.4% within 50–100 µm, 26.9% within the 100–250 µm, 17.2% within 250–500 µm, 8.2% within 500–1000 µm, and 2.2% within the size range of 1000–5000 µm. Among all MF particles, the most abundant size ranges in the DW and SW samples were 100–250 and 20–50 µm, respectively. The dominant size range of detected MFs in both environmental conditions and both brands was 20–50 µm (Fig. 3 (a) and Table S4). The most prevalent size ranges at different exposure times of 1, 2, 7, 15, 30, and 60 days were 250–500, 100–250, 100–250, 20–50, 20–50, 20–50 µm, respectively (Fig. 3 (b), and Table S4). Overall, the predominant size ranges of identified MFs in all CFs samples were as follows: 20–50 µm, 100–250 µm, 50–100 µm, 250–500 µm, 500–1000 µm, and 500–1000 µm (Fig. 3 (c), and Table S4). Considering the predominant size range of 20–50 µm, it seems likely that MFs with a size < 20 µm are present as well that could not be detected in the present study due to the limitation of analytical methods. The former studies did not report the abundant size range of MP fibers released from CFs or CBs. However, the dominant size of detected MPs in the coastal sediment of Balaban Lake, Turkey contaminated by CBs was reported as 100–250 µm 51 . On the other hand, the predominant size category of cellulose acetate MFs in the sediment samples collected from Narragansett Bay, USA, was 601–800 µm 37 . In other studies conducted in Iran, the majority of MP particles in the coastal sediment of the Persian Gulf were in the size range of 100–500 µm 52 and 2–5 mm 9 . It should be noted that the difference in the size of detected MPs in the mentioned studies can be due to different analytical methods used. Plastic particles are broken into finer particles, including NPs and MPs, with various shapes and sizes by thermal and mechanical processes 53 . After exposure to UV light, the surface shape of MP particles is changed and cracked into smaller particles in the environment 54 . The size MPs influences the biological toxicity degree 55 . The hazards posed by MPs increase with decreasing size, ascribed to increased bioavailability, a greater surface area to volume ratio, and the potential for transfer at cellular or tissue level 56 . MP particles smaller than 150 µm can translocate into human tissues 57 , which may be the most relevant size class from a toxicologically for trophic transmission through seafood and marine mammals with similar physiology 58 . The color percentages of MFs released via CFs are presented in Fig. 4 and Table S4. Different MFs colors, including white/transparent, black/gray, blue/green, and red/brown were detected in the samples. The most prevalent color of MFs released from CFs of different brands, different water types, different environment conditions, and exposure times was white/transparent (Fig. 4 (a, b, and c) and Table S4). It should be noted that the color of MPs detached from CBs into water is not reported in the former studies. In a research in Narragansett Bay, USA, white cellulose acetate fibers were reported as the dominant color of detected MFs in the sediments 37 . The prevalence of white/transparent MPs released from CBs or CFs can be due to the white color of cellulose acetate esters packed tightly together to make a CF 41 . The color diversity of MP particles fully illustrated the diversification of MPs pollution sources 59 . Marine organisms may mistakenly swallow MPs as a food source because of their apparent similarity to bait. Different colored MPs may transfer from a lower level of trophic via the food chain, which can cause various ecological and health hazards 60 . 3.3. MFs Polymer types In total, 30 suspected particles were undergoing micro-Raman analysis, of which 26 particles were positively recognized as synthetic polymers (86%), and 4 particles were not recognized as polymers (14%). The polymer types of released MFs from CF samples into water are shown in Fig. 5 . Cellulose acetate comprised 93% of detected MFs, followed by polyamide (5%) and polyethylene (2%). The current study, however, was consistent with earlier studies 1 , 61 , 62 . In a research in Spain, the most abundant MFs leached from smoked CFs was cellulose acetate 1 . In another research in Iran, the main polymer type in table salt was reported cellulose acetate that can be ascribed to the unmanaged plastic waste in the environment, such as CFs and textiles 61 . Cellulose acetate is extensively applied to manufacture a CF 63 . Therefore, CBs are known as a primary source of cellulose acetate, often discarded into water bodies 64 . Cellulose acetate is one of the most abundant MFs among identified MP types in coastal environments worldwide and CB are one of the most detected litters in coastal regions 65 , 66 . Polyethylene glycol as a plasticizer is added to cellulose acetate produced from cellulose through the acetylation process 67 . Polyamide and polyethylene are commonly used polymers for various applications in cigarettes, such as packaging materials and printing inks 68 . Polyamide polymer is mainly used in paper and plastic printing inks 69 . Polyethylene waxes as additives are applied in printing inks to decrease the blockage and offsetting of stacked sheets, improve resistance to scratch and scuff,, and change the coefficient of slip or friction 70 . Consequently, the presence of polyamides and polyethylene polymers among the detected MP types in the present study can be explained by using ink to write the brand on cigarette paper. 3.4. Elemental analysis The surface analysis of MFs was performed using SEM-EDS and demonstrated in Fig. 6 (a, b, c, d, e, and f). After 1, 30, and 60 days of exposure time in DW, oxygen (O) and carbon (C) signals appeared in all cases. The MFs in SW showed similar EDX spectra to DW starting from 1 day of exposure. After 30 days, C, O, sodium (Na), and chlorine (Cl) signals were also displayed. At 60 days of exposure in SW, C, O, Na, Cl, magnesium (Mg), silicon (Si), calcium (Ca), and aluminum (Al) signals were observed. The main elements in the plastic materials are C and O. Other elements are possibly originated from utilized chemical additives in the plastic polymers production or absorbed from exterior substances 71 . For example, in the plastic manufacturing industry, Ca, Al, Mg, Si, and Na are commonly utilized in different hydrocarbons, which decrease the oxidation cycle 72 . Different elements, such as Cl and Al, can be absorbed from the environment, particularly the marine ecosystem, on the MPs surface 73 . The high salinity of the marine environment can lead to the Na and Cl ions adsorption on the surface of MP 74 . As seen in Fig. 6 (c and f), the micrographs of MP fiber samples at an exposure time of 60 days, especially in SW samples, show high roughness of the surface and some ruptures, which can occur due to their weathering in the environment. Generally, the surfaces of MP were more susceptible to weathering in salty environments, as illustrated in former studies in China 75 and India 76 . The more irregular the MPs surface, the greater the expected absorption 77 . Moreover, irregular MPs have higher eco-toxicological impacts on living organisms 78 . The contaminants concentration, such as heavy metals, on the MPs surface mainly depends on the sorption properties of polymers 79 . In determining the capacities of adsorption, the weathering processes role is more significant compared to the plastic type 80 . Weathering and polymer aging can affect the cracks on the MPs surface and lead to fragmentation into more minor MPs or NPs 81 . Various factors, for instance temperature, seawater salinity, currents and waves, winds, and microbial community composition may cause surface weathering of MPs 82 . The MPs surface for adsorption of chemical elements in the environment can be changed by weathering and physical abrasion because of increasing their surface area and formation of anionic active locations 80 . The chemical elements adsorption on MP particles increases during degradation because of their larger surface and smaller size 83 . 3.5. Environmental risk of MFs The PLI evaluates the MP contamination degree in different media 84 . The status of MF contamination released from CF samples into different water is displayed in Fig. 7 (a). The calculated PLI values released from CFs into the water in the lab and under solar light environments were greater than 30, which indicates severe pollution (hazard category IV). In accordance with the results of this study, the PLI values of MPs in the seawater 21 , coastal sediment 52 , and urban runoff 11 showed severe pollution. The evaluated RQ values of CF samples are also illustrated in Fig. 7 (b). The values of RQ were greater than 1 that indicated a high risk. This study's findings agreed with the results of a former study on the Persian Gulf seawater and ballast water 21 . The RQ levels of MP particles in the samples of surface water collected from the Yongjiang River, China, were also investigated, and a high risk was demonstrated 35 . Plastic products can release MP particles and chemical additives in the environment, threatening human health 85 . Sunlight and heat can lead to the weathering of MP particles in the aquatic and terrestrial environments, resulting in the hazardous additives release 86 . In addition, MPs may absorb different contaminants, for instance persistent organic pollutants (POPs) 87 and heavy metals 9 , 88 from the environment, therefore increasing their toxic impacts on the water organisms 89 . However, the effect of MP shape and size is also considerable in MP environmental eco-toxicological and bio-reactivity impacts 90 . The eco-toxicological effects of environmental MFs released from CBs or CFs, particularly cellulose acetate, remain largely unknown and should be addressed in future studies. 3.6. MFs Emission rate through CBs into water environments MFs release through CFs into aquatic ecosystems, given the large number of CFs littered into the environment worldwide, can be a special ecological concern. So far, there has been no evaluation of the transmission of MFs through CFs to the aquatic environment worldwide. In this study, by considering the mean levels of MFs released from CF samples into the water at different contact times (Fig. 2 and Table S3) and the mass of discarded CFs every year globally (~ 845000 tons) 91 , the number of released MFs into the aquatic environment on a worldwide scale was estimated. As presented in Fig. 8 , CFs may release 14×10 12 , 19×10 12 , 24×10 12 , 32×10 12 , 38×10 12 , and 51×10 12 MFs into aquatic environments within 1, 2, 7, 15, 30, and 60 days of exposure, respectively. In former studies, other contaminants emission rate via CBs, including metal (loid)s 92 , BTEX 93 , PAHs 94 , aromatic amines 25 , and nicotine 95 , leached from CBs into aquatic environments have been estimated and reported. Thus, further studies are needed to elucidate the factors, which may affect the toxic contaminants release via CBs into various ecosystems as well as specify the long-term release burden. 4. Limitations The present study had uncertainties and limitations in evaluating the level, size, and polymer types of released MFs from CF samples. No study provides quantitative data on the presence of MFs released from CFs or CBs, preventing a detailed evaluation of the occurrence profiles of MFs in the environment. As an important subject, there are no standard methods for identifying MPs, reducing the comparability between various studies. The typical method for quantifying MFs primarily focuses on determining MPs number but not the mass. Only MFs larger than 20 µm were identified by visual identification in this study, and this can be the major limitation of this research that led to vastly underestimating the number of released MPs via CFs. Quantitation of MFs mass can provide valuable data to understand the levels of MFs, especially small-size MFs (< 20 µm), which cannot be detected by visual identification. Another limitation of this research was the analysis of MF types, as not all suspected MF particles were analyzed by micro-Raman because of the high number of detected particles. This can create some degree of uncertainty. Furthermore, no uniform standard models exist for ecological and health risk assessment of MPs. 5. Conclusion This research reported the occurrence and ecological risk of MFs released from CFs into the water environment under the impact of different factors, including cigarette brand, type of water, environmental condition, and exposure times. The highest MFs were observed in SW under OE conditions at an exposure time of 60 days. MFs were mainly featured with sizes ranging from 20–50 µm. In terms of polymer types, cellulose acetate was the predominant one. The risk assessment results indicated potential ecological risk. According to the findings of this research, MFs release from CFs into the aquatic environment and may adversely affect the ecosystem. Further studies on the release of related contaminants with MFs via CB litters and the effects of various factors, for example organic/inorganic contents, temperature, salinity, and pH of aquatic environments, on the release of MFs from CFs are needed. Also, the mechanisms of MF migration from CFs into different water matrices are unclear, and further research on MFs is needed to elucidate the potential long-term consequences for ecosystem health. Finally, social/political actions must focus on performing effective strategies of waste management to restrict the entry of CB waste as a source of different contaminants, such as MFs and related toxic compounds, into beaches to ensure the conservation of aquatic ecosystems. Declarations Acknowledgment The authors are grateful to the Bushehr University of Medical Sciences for their financial support (grant No. 2517) and the Systems Environmental Health and Energy Research Center, The Persian Gulf Biomedical Science Research Institute's laboratory staff for their cooperation. Author contributions Azam Mohammadi: Formal Analysis, Investigation, Methodology, Software, Writing original draft, Writing-review & editing; Farkhondeh Bahrani: Investigation, Writing-review & editing; Gabriel E. De-la-Torre: Writing-review & editing; Reza Saeedi: Writing-review & editing; Gerrit Renner: Formal Analysis, Methodology, Software, Writing-review & editing; Torsten C. Schmidt: Conceptualization, Writing-review & editing; Sina Dobaradaran: Supervision, Conceptualization, Methodology, Writing-review & editing, Funding acquisition. All authors have read and agreed to the published version of the manuscript. Data availability The datasets generated and analyzed during the current study were available from the corresponding author on reasonable request. Ethics declarations Competing interests The authors declare no competing interests. References Belzagui F, Buscio V, Gutiérrez-Bouzán C, Vilaseca M. Cigarette butts as a microfiber source with a microplastic level of concern. Science of The Total Environment 2021;762:144165. Mendes DS, Silva DNN, Santiago LEP, Gomes VJC, Beasley CR, Fernandes MEB. Comprehensive risk assessment of microplastics in tidal channel sediments in amazonian mangroves (northern Brazil). Journal of Environmental Management 2024;366:121826. Hassan I, Sethupathi S, Bashir MJ, Munusamy Y, Chan CW. A systematic review of microplastics occurrence, characteristics, identification techniques and removal methods in ASEAN and its future prospects. Journal of Environmental Chemical Engineering 2024:112305. Khedre AM, Ramadan SA, Ashry A, Alaraby M. Abundance and risk assessment of microplastics in water, sediment, and aquatic insects of the Nile River. Chemosphere 2024;353:141557. Yadav N, Hakkarainen M. Degradable or not? Cellulose acetate as a model for complicated interplay between structure, environment and degradation. Chemosphere 2021;265:128731. Ge J, Li H, Liu P, Zhang Z, Ouyang Z, Guo X. Review of the toxic effect of microplastics on terrestrial and aquatic plants. Science of the Total Environment 2021;791:148333. Yang L, Qiao F, Lei K, et al. Microfiber release from different fabrics during washing. Environmental Pollution 2019;249:136-143. Mishra S, charan Rath C, Das AP. Marine microfiber pollution: a review on present status and future challenges. Marine pollution bulletin 2019;140:188-197. Dobaradaran S, Schmidt TC, Nabipour I, et al. Characterization of plastic debris and association of metals with microplastics in coastline sediment along the Persian Gulf. Waste management 2018;78:649-658. Bronzo L, Lusher AL, Schøyen M, Morigi C. Accumulation and distribution of microplastics in coastal sediments from the inner Oslofjord, Norway. Marine pollution bulletin 2021;173:113076. Hajiouni S, Mohammadi A, Ramavandi B, et al. Occurrence of microplastics and phthalate esters in urban runoff: a focus on the Persian Gulf coastline. Science of the Total Environment 2022;806:150559. Treilles R, Gasperi J, Gallard A, et al. Microplastics and microfibers in urban runoff from a suburban catchment of Greater Paris. Environmental pollution 2021;287:117352. Mohammadi A, Malakootian M, Dobaradaran S, Hashemi M, Jaafarzadeh N, De-la-Torre GE. Occurrence and ecological risks of microplastics and phthalate esters in organic solid wastes: In a landfill located nearby the Persian Gulf. Chemosphere 2023;332:138910. Tan M, Sun Y, Gui J, et al. Distribution characteristics of microplastics in typical organic solid wastes and their biologically treated products. Science of the Total Environment 2022;852:158440. Mohammadi A, Malakootian M, Dobaradaran S, Hashemi M, Jaafarzadeh N. Occurrence, seasonal distribution, and ecological risk assessment of microplastics and phthalate esters in leachates of a landfill site located near the marine environment: Bushehr port, Iran as a case. Science of The Total Environment 2022;842:156838. Su Y, Zhang Z, Wu D, Zhan L, Shi H, Xie B. Occurrence of microplastics in landfill systems and their fate with landfill age. Water research 2019;164:114968. Kashfi FS, Ramavandi B, Arfaeinia H, et al. Occurrence and exposure assessment of microplastics in indoor dusts of buildings with different applications in Bushehr and Shiraz cities, Iran. Science of The Total Environment 2022;829:154651. Soltani NS, Taylor MP, Wilson SP. International quantification of microplastics in indoor dust: prevalence, exposure and risk assessment. Environmental Pollution 2022;312:119957. Akhbarizadeh R, Dobaradaran S, Torkmahalleh MA, Saeedi R, Aibaghi R, Ghasemi FF. Suspended fine particulate matter (PM2. 5), microplastics (MPs), and polycyclic aromatic hydrocarbons (PAHs) in air: their possible relationships and health implications. Environmental Research 2021;192:110339. Liao Z, Ji X, Ma Y, et al. Airborne microplastics in indoor and outdoor environments of a coastal city in Eastern China. Journal of Hazardous Materials 2021;417:126007. Zendehboudi A, Mohammadi A, Dobaradaran S, et al. Analysis of microplastics in ships ballast water and its ecological risk assessment studies from the Persian Gulf. Marine Pollution Bulletin 2024;198:115825. Su Q, Li Y, Lu N, et al. Abundance, characteristics and ecological risk assessment of microplastics in ship ballast water in ports around Liaodong Peninsula, China. Marine Pollution Bulletin 2024;207:116812. Araújo MCB, Costa MF. A critical review of the issue of cigarette butt pollution in coastal environments. Environmental research 2019;172:137-149. El Fadili H, Ben Ali M, El Mahi M, Lotfi EM. Turning Cigarette Butts (CBs) into Valuable Resources: Technical Potential and Drawbacks. Functionalized Cellulose Materials: Sustainable Manufacturing and Applications: Springer, 2025: 213-228. Dobaradaran S, Mutke XA, Schmidt TC, Swiderski P, De-la-Torre GE, Jochmann MA. Aromatic amines contents of cigarette butts: fresh and aged cigarette butts vs unsmoked cigarette. Chemosphere 2022;301:134735. Soleimani F, Dobaradaran S, De-la-Torre GE, Schmidt TC, Saeedi R. Content of toxic components of cigarette, cigarette smoke vs cigarette butts: A comprehensive systematic review. Science of the Total Environment 2022;813:152667. Joly F-X, Coulis M. Comparison of cellulose vs. plastic cigarette filter decomposition under distinct disposal environments. Waste Management 2018;72:349-353. Shen M, Li Y, Song B, Zhou C, Gong J, Zeng G. Smoked cigarette butts: Unignorable source for environmental microplastic fibers. Science of the Total Environment 2021;791:148384. Hidalgo-Ruz V, Gutow L, Thompson RC, Thiel M. Microplastics in the marine environment: a review of the methods used for identification and quantification. Environmental science & technology 2012;46:3060-3075. Miller EA, Yamahara KM, French C, Spingarn N, Birch JM, Van Houtan KS. A Raman spectral reference library of potential anthropogenic and biological ocean polymers. Scientific Data 2022;9:780. Tomlinson D, Wilson J, Harris C, Jeffrey D. Problems in the assessment of heavy-metal levels in estuaries and the formation of a pollution index. Helgoländer meeresuntersuchungen 1980;33:566-575. Xu P, Peng G, Su L, Gao Y, Gao L, Li D. Microplastic risk assessment in surface waters: A case study in the Changjiang Estuary, China. Marine pollution bulletin 2018;133:647-654. Uddin S, Fowler SW, Saeed T. Microplastic particles in the Persian/Arabian Gulf–a review on sampling and identification. Marine pollution bulletin 2020;154:111100. Everaert G, Van Cauwenberghe L, De Rijcke M, et al. Risk assessment of microplastics in the ocean: Modelling approach and first conclusions. Environmental pollution 2018;242:1930-1938. Zhang X, Leng Y, Liu X, Huang K, Wang J. Microplastics’ pollution and risk assessment in an urban river: a case study in the Yongjiang River, Nanning City, South China. Exposure and Health 2020;12:141-151. Andrady AL. Microplastics in the marine environment. Marine pollution bulletin 2011;62:1596-1605. Cashman MA, Langknecht T, El Khatib D, et al. Quantification of microplastics in sediments from Narragansett Bay, Rhode Island USA using a novel isolation and extraction method. Marine pollution bulletin 2022;174:113254. Laycock B, Nikolić M, Colwell JM, et al. Lifetime prediction of biodegradable polymers. Progress in Polymer Science 2017;71:144-189. Chamas A, Moon H, Zheng J, et al. Degradation rates of plastics in the environment. ACS Sustainable Chemistry & Engineering 2020;8:3494-3511. Gewert B, Plassmann M, Sandblom O, MacLeod M. Identification of chain scission products released to water by plastic exposed to ultraviolet light. Environmental Science & Technology Letters 2018;5:272-276. De Fenzo A, Giordano M, Sansone L. A clean process for obtaining high-quality cellulose acetate from cigarette butts. Materials 2020;13:4710. Luo H, Tu C, He D, et al. Interactions between microplastics and contaminants: A review focusing on the effect of aging process. Science of the Total Environment 2023:165615. Zambrano MC, Pawlak JJ, Daystar J, Ankeny M, Cheng JJ, Venditti RA. Microfibers generated from the laundering of cotton, rayon and polyester based fabrics and their aquatic biodegradation. Marine pollution bulletin 2019;142:394-407. Jiang Y, Zhao Y, Wang X, Yang F, Chen M, Wang J. Characterization of microplastics in the surface seawater of the South Yellow Sea as affected by season. Science of the Total Environment 2020;724:138375. Yadav N, Hakkarainen M. Degradation of Cellulose Acetate in Simulated Aqueous Environments: One‐Year Study. Macromolecular Materials and Engineering 2022;307:2100951. Suhrhoff TJ, Scholz-Böttcher BM. Qualitative impact of salinity, UV radiation and turbulence on leaching of organic plastic additives from four common plastics—A lab experiment. Marine pollution bulletin 2016;102:84-94. Zhang P, Huang P, Sun H, Ma J, Li B. The structure of agricultural microplastics (PT, PU and UF) and their sorption capacities for PAHs and PHE derivates under various salinity and oxidation treatments. Environmental pollution 2020;257:113525. Naik RK, Chakraborty P, D’Costa PM, Anilkumar N, Mishra R, Fernandes V. A simple technique to mitigate microplastic pollution and its mobility (via ballast water) in the global ocean. Environmental Pollution 2021;283:117070. Fred-Ahmadu OH, Bhagwat G, Oluyoye I, Benson NU, Ayejuyo OO, Palanisami T. Interaction of chemical contaminants with microplastics: Principles and perspectives. Science of the Total Environment 2020;706:135978. Zepnik S, Kabasci S, Radusch H-J. Influence of external plasticization on rheological and thermal properties of cellulose acetate with respect to its foamability. 2012. Ertaş A, Gökçe B, Tüney İ. Risk assessment of cigarette butts and microplastic pollution in a drinking and irrigation water basin of West Anatolia, Türkiye. Environmental Monitoring and Assessment 2024;196:676. Gholizadeh M, Shadi A, Abadi A, et al. Exploring the microplastic pollution: Unveiling origins and varieties in coastal sediments and waters of the Bushehr Province, Persian Gulf, Iran. Marine Pollution Bulletin 2024;198:115939. Alimba CG, Faggio C. Microplastics in the marine environment: Current trends in environmental pollution and mechanisms of toxicological profile. Environmental toxicology and pharmacology 2019;68:61-74. Sørensen L, Groven AS, Hovsbakken IA, et al. UV degradation of natural and synthetic microfibers causes fragmentation and release of polymer degradation products and chemical additives. Science of the Total Environment 2021;755:143170. Eerkes-Medrano D, Leslie HA, Quinn B. Microplastics in drinking water: A review and assessment. Current Opinion in Environmental Science & Health 2019;7:69-75. Simon-Sánchez L, Vianello A, Kirstein IV, Molazadeh M-S, Lorenz C, Vollertsen J. Assessment of microplastic pollution and polymer risk in the sediment compartment of the Limfjord, Denmark. Science of the Total Environment 2024;950:175017. Wright SL, Kelly FJ. Plastic and human health: a micro issue? Environmental science & technology 2017;51:6634-6647. Foley CJ, Feiner ZS, Malinich TD, Höök TO. A meta-analysis of the effects of exposure to microplastics on fish and aquatic invertebrates. Science of the total environment 2018;631:550-559. Bian P, Liu Y, Zhao K, et al. Spatial variability of microplastic pollution on surface of rivers in a mountain-plain transitional area: A case study in the Chin Ling-Wei River Plain, China. Ecotoxicology and Environmental Safety 2022;232:113298. Hamzah SR, Anuar ST, Khalik WMAWM, Kolandhasamy P, Ibrahim YS. Ingestion of microplastics by the estuarine polychaete, Namalycastis sp. in the Setiu Wetlands, Malaysia. Marine pollution bulletin 2021;170:112617. Taghipour H, Ghayebzadeh M, Mousavi SMS, Sharifi H, Payandeh A. Incidence and exposure to microplastics in table salt present in the Iran market. Toxicology Reports 2023;11:129-140. Priyambada G, Kurniawan B, Sitompul RG, Darmayanti L. The abundance of microplastics in Siak tributary sediments in the watershed area, Pekanbaru City, Riau (Case Study Sago River). Materials Today: Proceedings 2023;87:272-277. Novotny TE, Hamzai L. Cellulose acetate cigarette filter is hazardous to human health. BMJ Publishing Group Ltd, 2024. Fong J, Lee SHR, Sun Y, et al. Litter traps: A comparison of four marine habitats as sinks for anthropogenic marine macro-litter in Singapore. Marine Pollution Bulletin 2023;196:115645. Bridson JH, Patel M, Lewis A, Gaw S, Parker K. Microplastic contamination in Auckland (New Zealand) beach sediments. Marine Pollution Bulletin 2020;151:110867. Murphy L, Germaine K, Kakouli-Duarte T, Cleary J. Assessment of microplastics in Irish river sediment. Heliyon 2022;8. Díaz-Mendoza C, Mouthon-Bello J, Botero CM, Acevedo-Barrios R, Gutiérrez L. Microbiological analysis of cigarette butts and cigarette butt fibers on a tourist beach in Cartagena, Colombia. Scientific Reports 2025;15:14510. Gregor-Svetec D. Polymers in printing filaments. Polymers for 3D printing: Elsevier, 2022: 155-269. Ramadan AM, Gomaa AZ, Abdallah MA. Preparation and Evaluation of Polyamides for Printing Ink. Egyptian Journal of Chemistry 2020;63:1639-1653. Lamb JV, Buffet J-C, Turner ZR, Khamnaen T, O’Hare D. Metallocene polyethylene wax synthesis. Macromolecules 2020;53:5847-5856. do Sul JAI, Costa MF. The present and future of microplastic pollution in the marine environment. Environmental pollution 2014;185:352-364. Bolgar M, Hubball J, Groeger J, Meronek S. Handbook for the chemical analysis of plastic and polymer additives: CRC Press, 2007. Karami A, Golieskardi A, Choo CK, Larat V, Karbalaei S, Salamatinia B. Microplastic and mesoplastic contamination in canned sardines and sprats. Science of the total environment 2018;612:1380-1386. Bhatnagar A, Devi P. Water quality guidelines for the management of pond fish culture. International journal of environmental sciences 2013;3:1980-2009. Gao L, Fu D, Zhao J, et al. Microplastics aged in various environmental media exhibited strong sorption to heavy metals in seawater. Marine Pollution Bulletin 2021;169:112480. Veerasingam S, Saha M, Suneel V, et al. Characteristics, seasonal distribution and surface degradation features of microplastic pellets along the Goa coast, India. Chemosphere 2016;159:496-505. Razanajatovo RM, Ding J, Zhang S, Jiang H, Zou H. Sorption and desorption of selected pharmaceuticals by polyethylene microplastics. Marine pollution bulletin 2018;136:516-523. Schwarzer M, Brehm J, Vollmer M, et al. Shape, size, and polymer dependent effects of microplastics on Daphnia magna. Journal of Hazardous Materials 2022;426:128136. Vetrimurugan E, Jonathan M, Sarkar S, et al. Occurrence, distribution and provenance of micro plastics: A large scale quantitative analysis of beach sediments from southeastern coast of South Africa. Science of the Total Environment 2020;746:141103. Holmes LA, Turner A, Thompson RC. Interactions between trace metals and plastic production pellets under estuarine conditions. Marine Chemistry 2014;167:25-32. Zheng Y, Hamed M, De-la-Torre GE, et al. Holes on surfaces of the weathered plastic fragments from coastal beaches. Marine Pollution Bulletin 2023;193:115180. Arp HPH, Kühnel D, Rummel C, et al. Weathering plastics as a planetary boundary threat: exposure, fate, and hazards. Environmental science & technology 2021;55:7246-7255. Torres FG, Dioses-Salinas DC, Pizarro-Ortega CI, De-la-Torre GE. Sorption of chemical contaminants on degradable and non-degradable microplastics: Recent progress and research trends. Science of the Total Environment 2021;757:143875. Shekoohiyan S, Akbarzadeh A. The abundance of microplastic pollution along the Jajroud river of Tehran: estimating the water quality index and the ecological risk. Ecological Indicators 2022;145:109629. Liu Y, Li Z, Jalón-Rojas I, et al. Assessing the potential risk and relationship between microplastics and phthalates in surface seawater of a heavily human-impacted metropolitan bay in northern China. Ecotoxicology and Environmental Safety 2020;204:111067. Ranjani M, Veerasingam S, Venkatachalapathy R, et al. Assessment of potential ecological risk of microplastics in the coastal sediments of India: a meta-analysis. Marine Pollution Bulletin 2021;163:111969. Tan X, Yu X, Cai L, Wang J, Peng J. Microplastics and associated PAHs in surface water from the Feilaixia Reservoir in the Beijiang River, China. Chemosphere 2019;221:834-840. Kim D, Chae Y, An Y-J. Mixture toxicity of nickel and microplastics with different functional groups on Daphnia magna. Environmental science & technology 2017;51:12852-12858. Mai Y, Peng S, Lai Z, Wang X. Measurement, quantification, and potential risk of microplastics in the mainstream of the Pearl River (Xijiang River) and its estuary, Southern China. Environmental Science and Pollution Research 2021;28:53127-53140. Bucci K, Rochman CM. Microplastics: a multidimensional contaminant requires a multidimensional framework for assessing risk. Microplastics and Nanoplastics 2022;2:7. Carlozo L. Cigarettes: 1.7 billion pounds of trash. Chicago Tribune 2008;18. Akhbarizadeh R, Dobaradaran S, Parhizgar G, Schmidt TC, Mallaki R. Potentially toxic elements leachates from cigarette butts into different types of water: a threat for aquatic environments and ecosystems? Environmental research 2021;202:111706. Dobaradaran S, Schmidt TC, Kaziur-Cegla W, Jochmann MA. BTEX compounds leachates from cigarette butts into water environment: a primary study. Environmental Pollution 2021;269:116185. Dobaradaran S, Schmidt TC, Lorenzo-Parodi N, et al. Cigarette butts: an overlooked source of PAHs in the environment? Environmental pollution 2019;249:932-939. Dobaradaran S, Telgheder U, De-la-Torre GE, Rockel SP, Mutke XA, Schmidt TC. Elucidating nicotine transfer into water environments via cigarette butt remaining parts. Environmental Pollution 2024;341:122943. Additional Declarations No competing interests reported. Supplementary Files Supplementary.docx Cite Share Download PDF Status: Published Journal Publication published 22 Oct, 2025 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 22 Jul, 2025 Reviews received at journal 20 Jul, 2025 Reviewers agreed at journal 19 Jul, 2025 Reviews received at journal 03 Jul, 2025 Reviewers agreed at journal 25 Jun, 2025 Reviewers invited by journal 25 Jun, 2025 Editor assigned by journal 19 Jun, 2025 Editor invited by journal 19 Jun, 2025 Submission checks completed at journal 18 Jun, 2025 First submitted to journal 10 Jun, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6860318","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":476661577,"identity":"a504be00-0eb7-4b41-aa5e-8e2f6094925a","order_by":0,"name":"Azam Mohammadi","email":"","orcid":"","institution":"Bushehr University of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Azam","middleName":"","lastName":"Mohammadi","suffix":""},{"id":476661578,"identity":"67605ab1-29c0-493f-b2f9-a3e1f8553ae6","order_by":1,"name":"Farkhondeh Bahrani","email":"","orcid":"","institution":"Bushehr University of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Farkhondeh","middleName":"","lastName":"Bahrani","suffix":""},{"id":476661579,"identity":"78d135cd-2a9d-4f23-a1d9-32440e6cd9ed","order_by":2,"name":"Gabriel Enrique De-la-Torre","email":"","orcid":"","institution":"Universidad San Ignacio de Loyola","correspondingAuthor":false,"prefix":"","firstName":"Gabriel","middleName":"Enrique","lastName":"De-la-Torre","suffix":""},{"id":476661580,"identity":"f3fccbbb-998b-49fb-833e-8d3724208648","order_by":3,"name":"Reza Saeedi","email":"","orcid":"","institution":"Shahid Beheshti University of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Reza","middleName":"","lastName":"Saeedi","suffix":""},{"id":476661581,"identity":"e4faad82-c596-42ce-82e3-6209c401432f","order_by":4,"name":"Gerrit Renner","email":"","orcid":"","institution":"University of Duisburg-Essen","correspondingAuthor":false,"prefix":"","firstName":"Gerrit","middleName":"","lastName":"Renner","suffix":""},{"id":476661582,"identity":"b31d6fb4-30fc-4ce5-83af-8cc72f2cccc2","order_by":5,"name":"Torsten C. Schmidt","email":"","orcid":"","institution":"University of Duisburg-Essen","correspondingAuthor":false,"prefix":"","firstName":"Torsten","middleName":"C.","lastName":"Schmidt","suffix":""},{"id":476661583,"identity":"4e7ef199-9e79-46be-9df3-22bddf09b2f2","order_by":6,"name":"Sina Dobaradaran","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABBElEQVRIiWNgGAWjYBAC+WYgwcNwAMQ2ABFyIOLAAzxaDA6jaTEGa0nAp4UBTUtiA4jEq4Wd9+CHNxV35M3bD2/8XFFzJ31+2OGHQFvs5HQbcPmFL1lyzplnhnPOpBVLnjn2LHfj7TQDoJZkY7MDOKw5zGMgzdt2mHEGQ46BZAPb4dyNsxNAWg4kbsOtxfg3UIv9DP43xj8b/h1ON5yd/oGQFjOQLYkzJHLMJBvbDifIS+fgt8UAqMUS6JfkGRLPyiwb+w4bbpDOKTiQYIDbL/L9Z4xvAEPMdgZ/8uabDd8Oy8vPTt/84UOFnRxO72PaC1ZpQKxysL0NpKgeBaNgFIyCkQAA8C9oIHd3YlYAAAAASUVORK5CYII=","orcid":"","institution":"Bushehr University of Medical Sciences","correspondingAuthor":true,"prefix":"","firstName":"Sina","middleName":"","lastName":"Dobaradaran","suffix":""}],"badges":[],"createdAt":"2025-06-10 07:38:28","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6860318/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6860318/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-025-20771-7","type":"published","date":"2025-10-22T16:17:11+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":85652870,"identity":"98f7b725-4d18-4d5c-9109-4c3a8fff9d2f","added_by":"auto","created_at":"2025-06-30 09:48:07","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":164066,"visible":true,"origin":"","legend":"\u003cp\u003eExperimental flowchart of study.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6860318/v1/3b8dfed24e13c28b84e80eb5.png"},{"id":85653870,"identity":"d4b24aff-24dc-4556-aecd-e30721d45b84","added_by":"auto","created_at":"2025-06-30 10:04:07","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":17169,"visible":true,"origin":"","legend":"\u003cp\u003eLevel of microfibers (items/g CFs) released from cigarette filter into different water samples at different exposure times (DW: distilled water, SW: seawater, LE: lab environment, and OE: outdoor environment).\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6860318/v1/84382d76e7194842e43dfd9f.png"},{"id":85653689,"identity":"c045948f-2296-4bad-8300-d57be58dabe0","added_by":"auto","created_at":"2025-06-30 09:56:07","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":76174,"visible":true,"origin":"","legend":"\u003cp\u003eSize distribution of microfibers released from cigarette filter into different water samples (DW: distilled water, SW: seawater, LE: lab environment, and OE: outdoor environment).\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6860318/v1/b046e7090f3d1a52fe42a67f.png"},{"id":85652874,"identity":"3c66a35c-1ca1-43e3-a678-e67f3ae8ff15","added_by":"auto","created_at":"2025-06-30 09:48:07","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":81540,"visible":true,"origin":"","legend":"\u003cp\u003eColor of microfibers released from cigarette filter into water samples (DW: distilled water, SW: seawater, LE: lab environment, and OE: outdoor environment).\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6860318/v1/cd46c00d796913d7c38b3890.png"},{"id":85652876,"identity":"cb0c490d-b7b2-462a-a773-4c9679cf74ef","added_by":"auto","created_at":"2025-06-30 09:48:07","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":9353,"visible":true,"origin":"","legend":"\u003cp\u003ePolymer type of microfibers released from cigarette filter into water.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6860318/v1/5e853e29a3eb08d186b57982.png"},{"id":85652880,"identity":"36391287-876c-480c-a0eb-e3b5091c877b","added_by":"auto","created_at":"2025-06-30 09:48:07","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":301625,"visible":true,"origin":"","legend":"\u003cp\u003eSEM and EDS analysis of identified microfibers under two water treatments and selected exposure times (DW: distilled water and SW: seawater).\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-6860318/v1/5e8285aa662ed8d45930486b.png"},{"id":85653692,"identity":"6072e23c-8549-45b7-b394-a6590d116eed","added_by":"auto","created_at":"2025-06-30 09:56:07","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":21235,"visible":true,"origin":"","legend":"\u003cp\u003ePLI (a) and RQ (b) of microfibers released from cigarette Filters (filter + paper) into water samples at different exposure times (PLI: pollution load index, RQ: risk quotient, DW: distilled water, SW: seawater, LE: lab environment, and OE: outdoor environment).\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-6860318/v1/80b2c667c4062ce87715bf7d.png"},{"id":85652881,"identity":"2031a8c4-e7cd-431c-9fec-d247ab3b1bab","added_by":"auto","created_at":"2025-06-30 09:48:07","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":11644,"visible":true,"origin":"","legend":"\u003cp\u003eMicrofibers emission rate through cigarette filter into aquatic environments at different exposure times.\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-6860318/v1/4c3d945ca5aa53e18f2f78d8.png"},{"id":94490300,"identity":"71968b1f-8e5e-41aa-bbb8-e4a4b06f1a57","added_by":"auto","created_at":"2025-10-27 17:09:00","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1376494,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6860318/v1/26ac2989-3fb2-4b00-8d5e-8a045d71df57.pdf"},{"id":85654643,"identity":"ddd8d662-7b40-4fb3-be7e-887dd934d27e","added_by":"auto","created_at":"2025-06-30 10:12:07","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":61628,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementary.docx","url":"https://assets-eu.researchsquare.com/files/rs-6860318/v1/1d9d4df45d8228fcb44668eb.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Cigarette filters as a main microfibers source in aquatic environments: Phase I","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003ePlastic contamination is recently attracted significant consideration from the public section \u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. Microplastics (MPs) are emerging contaminants that are converting an increasing concern around the world because of their extensive incidence and harmful biological and ecological impacts \u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. MPs refer to plastic particles of 1 \u0026micro;m to 5 mm, differing in composition, size and shape \u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. MP particles can be classified into primary MPs manufactured for industrial use and secondary MPs produced from the breaking larger plastics \u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. Exposure of MP particles to external environmental factors, e.g., sunlight, mechanical wear, seawater, soil, and microorganisms, leads to their physical and chemical changes \u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eMPs release in the water and terrestrial environments can cause harm to living organisms \u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. Synthetic microfibers (MFs), as one of the major contaminants in the aquatic ecosystems, are secondary MPs \u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e, which aquatic species may consume mistakenly \u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. Recently, a growing number of researches have been performed on the MPs presence in different environmental samples, including coastline sediment \u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e, urban runoff \u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e, organic solid waste \u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e, landfill leachate \u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e, indoor dust \u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e, air \u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e, and ballast water \u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. However, a limited data exists on the exact role of CFs in releasing MFs into the aquatic environment \u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eBetween all the debris types identified in the environment, CBs are one of the most dominant \u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. Based on the reports, more than 5.8 trillion cigarettes are manufactured around the world annually, and more than 4.95 trillion CFs are improperly thrown away \u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e. Many CFs are dumped into the streets and the environment, transferred by rain or urban runoff to other ecosystems, such as coastal and marine environments \u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e. The used CFs contain different chemical contaminants \u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e, which may be leached into the surrounding environment and pose serious environmental risks. These toxic chemicals may also be associated with the released MFs via CFs and be easily transported across different environmental media.\u003c/p\u003e \u003cp\u003eThe tobacco CFs generally comprise over15,000 fiber string constructed from cellulose acetate with plasticizer additives, which can take up to 30 years to degrade under special conditions \u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e. Each discarded CF introduced into aquatic systems has the potential to release significant quantities of chemical compounds and MFs into the environment, posing a risk of acute toxicity to aquatic organisms \u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e. Because discarded CFs as a potential source of MFs and plastic additives can cause ecological hazards, it is necessary to determine the role of CFs in releasing MFs into the environment. While the detachment rate of MFs from smoked CFs has only been investigated in a previous study at an exposure time of one month \u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e, no prior research has yet reported the features of released MFs via CFs at different exposure times under different environmental condition as well as their environmental risks. Thus, the objectives of this research were to 1) Determine the levels and features (size, polymer type, and color) of released MFs via CFs into different water samples at various exposure times; 2) Compare the levels of released MFs via CFs between different brands of cigarette, water types, environment conditions, and exposure times; 3) Specify the pollution load index (PLI) and risk quotient (RQ) of released MFs via CFs into water at different exposure times; and 4) Estimate the emission rate of MFs via CFs into water bodies on a worldwide scale.\u003c/p\u003e"},{"header":"2. Methodology","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Sampling and experimental setup\u003c/h2\u003e \u003cp\u003eIn January 2023, 144 cigarette samples of two international cigarette brands, labeled as brand 1 and brand 2, were prepared from Bushehr, Iran, marketing. The release experiments of MFs via CFs were done in two water types [distilled water (DW) and seawater (SW)] under two different environmental conditions [lab environment (LE) without sun exposure and outdoor environment (OE) with sun exposure] at six different exposure times of 1, 2, 7, 15, 30, and 60-days. Each cigarette was cut from the filter side with a size of 3 cm by a sterile stainless-steel blade. 3 repetitions were performed for each exposure time with 3 CFs in each run. The mean CF weight (\u0026plusmn;\u0026thinsp;SD) of brand 1 and brand 2 were 0.173 (\u0026plusmn;\u0026thinsp;0.002) and 0.172 (\u0026plusmn;\u0026thinsp;0.003) g, respectively (Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e). For experiments, SW samples from the Persian Gulf were filtered via cellulose nitrate filter papers (Whatman, Maidstone, Kent, UK) with 0.45 \u0026micro;m pore-size. Also, DW (15 MΩ/cm) produced from an ELGA Purelab (Lane End, High Wycombe, UK) water purification system was applied to the experiment after filtering via filter papers with pore-size of 0.45 \u0026micro;m.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Release experiments of MFs\u003c/h2\u003e \u003cp\u003eThe CF samples of each brand were transported to a glass beaker. The samples were exposed to four conditions: DW/in LE, DW/in OE, SW/in LE, and SW/in OE. The water (DW or SW) was added to each beaker and maintained at different desired periods of 1, 2, 7, 15, 30, and 60 days. After each contact time, each sample was vacuum-filtered. Then, each filter was placed into a petri dish and air dried. A flowchart of the experimental workflow is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e1\u003c/span\u003e. This scheme shows 144 CF samples of two cigarette brands (72 each), investigated with different conditions at different exposure times.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Quantification and identification of MFs\u003c/h2\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003e2.3.1. Optical analysis\u003c/h2\u003e \u003cp\u003eAll particles suspected of being MFs were examined by an optical microscope (A. KR\u0026Uuml;SS Optronic, Germany) with a maximum 40x magnification. Then, the size and color of MFs were recorded and categorized. During visual recognition, we followed the guidelines proposed by Hidalgo-Ruz et al. (2012) study to decrease error \u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. To precise diagnose MFs from other probable crystal structures, such as salt pieces and chemical particles, a heated needle was applied in some cases. The stainless-steel probe diameter was used to measure the longest part of each MFs.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e \u003ch2\u003e2.3.2. Raman analysis\u003c/h2\u003e \u003cp\u003eThe polymer type of the extracted MFs was confirmed by a DXR3 Raman Microscope (Thermo Fisher) with a 10x magnification lens. All MF samples were placed onto prepared copper tapes for analysis, and a 785 nm laser was applied as the excitation source. The Raman spectra were obtained in the range of 400\u0026ndash;2450 cm⁻\u0026sup1;. The types of MFs were identified by the obtained spectra to a reference database library for the microscope. To identify the polymer type of MFs, the obtained Raman spectra were compared with a reference database library containing common MPs observed in environmental samples \u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. The matching algorithm applied a Cauchy-Schwarz distance metric to evaluate the similarity among the measured and reference spectra. The three best hits were identified, and a threshold value of 0.4 was applied to ensure robust matches. If the hit quality index (HQI) value exceeded 0.7, the corresponding database entry was considered an identification for the MFs. More details of Raman analysis are explained in the supplementary file.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e \u003ch2\u003e2.3.3. Scanning electron microscope coupled with an energy dispersive X-ray (SEM-EDS) analysis\u003c/h2\u003e \u003cp\u003eThe elemental composition and morphology of identified MFs were investigated by a SEM-EDS (TESCAN, Czech Republic). The selected MFs samples were prepared on double sided carbon conductive tape for the analysis. Furthermore, a layer of nanometric gold was used on the particles surface to prevent sample charging and enhance the quality of observation.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e2.4. Quality Assurance (QA)/Quality Control (QC)\u003c/h2\u003e \u003cp\u003eBefore usage to prevent contamination during the process, all tools applied for the collection of samples and lab analysis was rinsed with DW and concealed with aluminum foil. Clean gloves, Cotton masks, and cotton laboratory coats were worn in all steps. To eliminate the particles from them, the desks surface was cleansed with paper wipes. All water applied in the experiments was filtered via a cellulose nitrate membrane filter with a pore size of 0.45 \u0026micro;m. Blank samples were prepared by the similar processing methods used to the lab process. Then, the mean MFs number identified in the blank samples was deducted from the findings of the experimental sets. All experiments were done in three repetitions to enhance the results reliability, and the mean levels are presented here.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e2.5. Environmental risk assessment\u003c/h2\u003e \u003cp\u003eCommonly, the Pollution Load Index (PLI) is utilized to comprehensively evaluate the discharge pollution level \u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e. PLI was used to estimate the overall pollution level of MFs as follows \u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e:\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$$\\:{CF}_{i}=\\frac{{C}_{i}}{{C}_{oi}}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equ2\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ2\" name=\"EquationSource\"\u003e\n$$\\:PLI=\\sqrt{{CF}_{i}}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equ3\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ3\" name=\"EquationSource\"\u003e\n$$\\:{PLI}_{zone}=\\sqrt[n]{{PLI}_{1}\\times\\:{PLI}_{2}\\times\\:\\dots\\:\\times\\:{PLI}_{n}}\\:$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e3\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eHere, C\u003csub\u003ei\u003c/sub\u003e represents the mean number of MFs (items/ m\u003csup\u003e3\u003c/sup\u003e) released from CFs into the water, and C\u003csub\u003eoi\u003c/sub\u003e as the background level of MP particle represents the published lowest mean number of MPs (0.71 particles/m\u003csup\u003e3\u003c/sup\u003e) in the surface water \u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e. PLI were divided into four groups: without or very low contamination (class I: 10\u0026thinsp;\u0026gt;\u0026thinsp;PLI), low contamination (class II: 20\u0026thinsp;\u0026gt;\u0026thinsp;PLI\u0026thinsp;\u0026ge;\u0026thinsp;10), moderate contamination (class III: 30\u0026thinsp;\u0026gt;\u0026thinsp;PLI\u0026thinsp;\u0026ge;\u0026thinsp;20), and severe contamination (class IV: PLI\u0026thinsp;\u0026gt;\u0026thinsp;30) \u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe potential environmental risks of the identified MFs in water were evaluated by the risk quotient (RQ) technique that has been previously applied to assess the MPs risks in aquatic ecosystems. The RQ was calculated using the following formula \u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e:\u003cdiv id=\"Equ4\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ4\" name=\"EquationSource\"\u003e\n$$\\:RQ=\\frac{\\text{M}\\text{E}\\text{C}}{\\text{P}\\text{N}\\text{E}\\text{C}}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e4\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere MEC is the level of MFs (items/m\u003csup\u003e3\u003c/sup\u003e) released from CFs into the water, PNEC is the predicted no-effect concentration below at which the organisms show negligible harmful effects. Based on the former study, The value of PNEC used was 4920 items/m\u0026sup3; \u003csup\u003e\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e. The estimated RQ was divided into two risk levels: RQ\u0026thinsp;\u0026lt;\u0026thinsp;1 indicates a negligible environmental risk; and RQ\u0026thinsp;\u0026gt;\u0026thinsp;1 shows a high potential of environmental risk \u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e2.5. Data analysis\u003c/h2\u003e \u003cp\u003eLevene and Shapiro-Wilks tests were applied to assess the normality and homogeneity of variances. One-way analysis of variance (ANOVA) as a parametric testing method and Tukey Post Hoc were applied to specify the differences among the MFs levels released from CFs at different exposure times. Furthermore, sample t-test analysis was applied to identify the differences among the levels of released MFs via two types of cigarette brands, waters, and environmental conditions. Statistically significant was accepted at p-value lower than 0.05. Microsoft Excel 2018 and SPSS 20 software were used to statistical analyses.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results and discussions","content":"\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.1. MFs released from CBs\u003c/h2\u003e \u003cp\u003eA mean of 1.33 particles/blank (range of 0 to 2) was identified in the six blank samples of brand 1, and a mean of 1.67 particles/blank (range of 1 to 3) in the six blank samples of brand 2 at different exposure times of 1, 2, 7, 15, 30, and 60-days, respectively. Two blank samples (in the LE and OE) for each brand were investigated at each exposure time. The detected MF particles in the blank samples were deducted from the counted MFs number in the experimental samples considering size, shape, and color.\u003c/p\u003e \u003cp\u003eMPs were found in both brands of cigarette at different exposure times. The details of released MFs via CFs into DW and SW in LE and OE conditions at different exposure times are presented in Table S2. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e2\u003c/span\u003e and Table S3, the mean level of released MFs at studied contact times of 1, 2, 7, 15, 30, and 60 days ranged from 5.88 to 34.77, 11.63\u0026ndash;35.66, 11.85\u0026ndash;47.16, 17.3\u0026ndash;63.4, 17.66\u0026ndash;75.9, and 30.32\u0026ndash;92.43 items/g CFs, respectively. The time-dependent release of MFs may be related to the physical degradation of CFs \u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e. The levels of MFs in the SW samples were greater compared to the DW samples at all exposure times. Significant differences (p-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05) were detected among the mean released MFs levels at different exposure times and water types. No significant differences (p-value\u0026thinsp;\u0026gt;\u0026thinsp;0.05) were found among the levels of MF released from different brands of cigarettes as well as the levels of MFs in two environmental conditions (Table S3). Only one study in Terrassa, Spain, investigated the levels of MFs leached from smoked CB via different cigarette brands in the laboratory environment, reporting 100 MFs per day with a size of \u0026lt;\u0026thinsp;0.2 mm released from every smoked cigarette in the first two weeks. As reported, three CBs without wrapping papers in each run were used to investigate the release of MFs from CBs into DW and synthetic SW. The samples were submitted to slow mechanical agitation and continuous UV light exposure for one month \u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. The higher MFs reported by Belzagui et al., 2021 compared to the current research can be due to the mechanical agitation applied in their study, which significantly enhances the detachment and breakdown of fibers. In their research, the most identified size of MFs was \u0026lt;\u0026thinsp;0.2 mm and the smallest and largest sizes of detected particles were not reported, while the size of MFs in the present study was in the range of 20-5000 \u0026micro;m. Considering the current valid methods in measuring MPs, the identified lower size (especially lower than 20 \u0026micro;m) is in doubt and may change the numbers of detected MFs. Thus, the different levels of MFs released from CBs and CFs can be associated with the difference in the type of cigarette (smoked or unsmoked), exposure condition, type of water, contact time, and analytical techniques used for extracting of MFs.\u003c/p\u003e \u003cp\u003eIn a previous study in Narragansett Bay, USA, the high abundance of cellulose acetate MFs in the sediments was attributed to sediment contamination with CFs \u003csup\u003e\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e. The CFs are constructed of cellulose acetate, considered a semi-synthetic polymer \u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. In addition to the structural characteristics, several environmental factors, including sunlight, temperature, pH, humidity, availability of nutrients, microorganisms, and oxygen, effect on the cellulose acetate degradation rate at any particular place \u003csup\u003e\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e. Exposure to solar irradiation may primarily influence on the fate of plastics and the amount of their physical and chemical degradation after disposal in the natural environment or landfills \u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e. Especially, contact to UV light causes scission of chain and consequent the polymer backbone oxidation \u003csup\u003e\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e\u003c/sup\u003e. Also, UV irradiation commonly increases the plastics biodegradability by introducing polar groups and enhancement of the surface area. Although the maximum absorption for cellulose acetate is \u0026sim;260 nm, the cut off for sunlight that reaches the Earth is approximately 300 nm. This shows that natural sunlight may not considerably degrade pure cellulose acetate \u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. Also, cellulose acetate is not readily biodegradable polymer. Thus, it may remain in the environment for many years \u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e. Other factors, for example water salinity and air temperature, can also affect the aging MPs process \u003csup\u003e\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eBasically, the enhancement of temperature causes the breaking MFs, especially cellulosic fibers \u003csup\u003e\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e. The salinity of seawater acts an essential role in the MPs distribution and their characteristics \u003csup\u003e\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e\u003c/sup\u003e. It should be noted that the salinity affects the chemical degradation rate of MFs, including cellulose acetate \u003csup\u003e\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e\u003c/sup\u003e. The salinity of seawater causes complex changes in water properties, for example ionic strength, polarity, and pH, which can influence on the degradation of plastic debris and the release of organic plastic additives \u003csup\u003e\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e\u003c/sup\u003e. The contaminants sorption on MPs is significantly related to changes in salinity. With increasing salinity, the electrical dual layer of MPs may compact for having a greater density, and the hydration layer thickness may reduce that can help to greater absorption of contaminants on MP particles \u003csup\u003e\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e\u003c/sup\u003e. MPs and connected contaminants in the marine environment may affect organisms or enter into food chains and eventually be consumed by humans \u003csup\u003e\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e\u003c/sup\u003e. Different chemical contaminants can be adsorbed on the surface of synthetic plastic materials \u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e\u003c/sup\u003e. Plasticizers, especially phthalates, are commonly added to cellulose acetate, which can migrate into the environment and subsequently cause harmful influences on human health \u003csup\u003e\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Physical characteristics of MFs\u003c/h2\u003e \u003cp\u003eThe size of identified MFs released via CFs was classified into six categories, as displayed in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e3\u003c/span\u003e and Table S4. Among the MFs leached from CFs of brand 1, 26.9% were within 20\u0026ndash;50 \u0026micro;m size range, 25% within 50\u0026ndash;100 \u0026micro;m size range, 23.1% within 100\u0026ndash;250 \u0026micro;m, 13.1% within 250\u0026ndash;500 \u0026micro;m, 6.2% within 500\u0026ndash;1000 \u0026micro;m, and 5.6% within 1000\u0026ndash;5000 \u0026micro;m size range. In the case of brand 2 of CFs, 29.1% of the MFs were within the size range of the 20\u0026ndash;50 \u0026micro;m size, 16.4% within 50\u0026ndash;100 \u0026micro;m, 26.9% within the 100\u0026ndash;250 \u0026micro;m, 17.2% within 250\u0026ndash;500 \u0026micro;m, 8.2% within 500\u0026ndash;1000 \u0026micro;m, and 2.2% within the size range of 1000\u0026ndash;5000 \u0026micro;m. Among all MF particles, the most abundant size ranges in the DW and SW samples were 100\u0026ndash;250 and 20\u0026ndash;50 \u0026micro;m, respectively. The dominant size range of detected MFs in both environmental conditions and both brands was 20\u0026ndash;50 \u0026micro;m (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e3\u003c/span\u003e (a) and Table S4). The most prevalent size ranges at different exposure times of 1, 2, 7, 15, 30, and 60 days were 250\u0026ndash;500, 100\u0026ndash;250, 100\u0026ndash;250, 20\u0026ndash;50, 20\u0026ndash;50, 20\u0026ndash;50 \u0026micro;m, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e3\u003c/span\u003e (b), and Table S4). Overall, the predominant size ranges of identified MFs in all CFs samples were as follows: 20\u0026ndash;50 \u0026micro;m, 100\u0026ndash;250 \u0026micro;m, 50\u0026ndash;100 \u0026micro;m, 250\u0026ndash;500 \u0026micro;m, 500\u0026ndash;1000 \u0026micro;m, and 500\u0026ndash;1000 \u0026micro;m (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e3\u003c/span\u003e (c), and Table S4). Considering the predominant size range of 20\u0026ndash;50 \u0026micro;m, it seems likely that MFs with a size\u0026thinsp;\u0026lt;\u0026thinsp;20 \u0026micro;m are present as well that could not be detected in the present study due to the limitation of analytical methods.\u003c/p\u003e \u003cp\u003eThe former studies did not report the abundant size range of MP fibers released from CFs or CBs. However, the dominant size of detected MPs in the coastal sediment of Balaban Lake, Turkey contaminated by CBs was reported as 100\u0026ndash;250 \u0026micro;m \u003csup\u003e\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e\u003c/sup\u003e. On the other hand, the predominant size category of cellulose acetate MFs in the sediment samples collected from Narragansett Bay, USA, was 601\u0026ndash;800 \u0026micro;m \u003csup\u003e\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e. In other studies conducted in Iran, the majority of MP particles in the coastal sediment of the Persian Gulf were in the size range of 100\u0026ndash;500 \u0026micro;m \u003csup\u003e\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e\u003c/sup\u003e and 2\u0026ndash;5 mm \u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. It should be noted that the difference in the size of detected MPs in the mentioned studies can be due to different analytical methods used. Plastic particles are broken into finer particles, including NPs and MPs, with various shapes and sizes by thermal and mechanical processes \u003csup\u003e\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e\u003c/sup\u003e. After exposure to UV light, the surface shape of MP particles is changed and cracked into smaller particles in the environment \u003csup\u003e\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e\u003c/sup\u003e. The size MPs influences the biological toxicity degree \u003csup\u003e\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e\u003c/sup\u003e. The hazards posed by MPs increase with decreasing size, ascribed to increased bioavailability, a greater surface area to volume ratio, and the potential for transfer at cellular or tissue level \u003csup\u003e\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e\u003c/sup\u003e. MP particles smaller than 150 \u0026micro;m can translocate into human tissues \u003csup\u003e\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e\u003c/sup\u003e, which may be the most relevant size class from a toxicologically for trophic transmission through seafood and marine mammals with similar physiology \u003csup\u003e\u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe color percentages of MFs released via CFs are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e4\u003c/span\u003e and Table S4. Different MFs colors, including white/transparent, black/gray, blue/green, and red/brown were detected in the samples. The most prevalent color of MFs released from CFs of different brands, different water types, different environment conditions, and exposure times was white/transparent (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e4\u003c/span\u003e (a, b, and c) and Table S4). It should be noted that the color of MPs detached from CBs into water is not reported in the former studies. In a research in Narragansett Bay, USA, white cellulose acetate fibers were reported as the dominant color of detected MFs in the sediments \u003csup\u003e\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e. The prevalence of white/transparent MPs released from CBs or CFs can be due to the white color of cellulose acetate esters packed tightly together to make a CF \u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e. The color diversity of MP particles fully illustrated the diversification of MPs pollution sources \u003csup\u003e\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e\u003c/sup\u003e. Marine organisms may mistakenly swallow MPs as a food source because of their apparent similarity to bait. Different colored MPs may transfer from a lower level of trophic via the food chain, which can cause various ecological and health hazards \u003csup\u003e\u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e3.3. MFs Polymer types\u003c/h2\u003e \u003cp\u003eIn total, 30 suspected particles were undergoing micro-Raman analysis, of which 26 particles were positively recognized as synthetic polymers (86%), and 4 particles were not recognized as polymers (14%). The polymer types of released MFs from CF samples into water are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e5\u003c/span\u003e. Cellulose acetate comprised 93% of detected MFs, followed by polyamide (5%) and polyethylene (2%). The current study, however, was consistent with earlier studies \u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e, \u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e62\u003c/span\u003e\u003c/sup\u003e. In a research in Spain, the most abundant MFs leached from smoked CFs was cellulose acetate \u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. In another research in Iran, the main polymer type in table salt was reported cellulose acetate that can be ascribed to the unmanaged plastic waste in the environment, such as CFs and textiles \u003csup\u003e\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e\u003c/sup\u003e. Cellulose acetate is extensively applied to manufacture a CF \u003csup\u003e\u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e\u003c/sup\u003e. Therefore, CBs are known as a primary source of cellulose acetate, often discarded into water bodies \u003csup\u003e\u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e64\u003c/span\u003e\u003c/sup\u003e. Cellulose acetate is one of the most abundant MFs among identified MP types in coastal environments worldwide and CB are one of the most detected litters in coastal regions \u003csup\u003e\u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e65\u003c/span\u003e, \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e66\u003c/span\u003e\u003c/sup\u003e. Polyethylene glycol as a plasticizer is added to cellulose acetate produced from cellulose through the acetylation process \u003csup\u003e\u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e67\u003c/span\u003e\u003c/sup\u003e. Polyamide and polyethylene are commonly used polymers for various applications in cigarettes, such as packaging materials and printing inks \u003csup\u003e\u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e68\u003c/span\u003e\u003c/sup\u003e. Polyamide polymer is mainly used in paper and plastic printing inks \u003csup\u003e\u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e69\u003c/span\u003e\u003c/sup\u003e. Polyethylene waxes as additives are applied in printing inks to decrease the blockage and offsetting of stacked sheets, improve resistance to scratch and scuff,, and change the coefficient of slip or friction \u003csup\u003e\u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e70\u003c/span\u003e\u003c/sup\u003e. Consequently, the presence of polyamides and polyethylene polymers among the detected MP types in the present study can be explained by using ink to write the brand on cigarette paper.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e3.4. Elemental analysis\u003c/h2\u003e \u003cp\u003eThe surface analysis of MFs was performed using SEM-EDS and demonstrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e6\u003c/span\u003e (a, b, c, d, e, and f). After 1, 30, and 60 days of exposure time in DW, oxygen (O) and carbon (C) signals appeared in all cases. The MFs in SW showed similar EDX spectra to DW starting from 1 day of exposure. After 30 days, C, O, sodium (Na), and chlorine (Cl) signals were also displayed. At 60 days of exposure in SW, C, O, Na, Cl, magnesium (Mg), silicon (Si), calcium (Ca), and aluminum (Al) signals were observed. The main elements in the plastic materials are C and O. Other elements are possibly originated from utilized chemical additives in the plastic polymers production or absorbed from exterior substances \u003csup\u003e\u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e71\u003c/span\u003e\u003c/sup\u003e. For example, in the plastic manufacturing industry, Ca, Al, Mg, Si, and Na are commonly utilized in different hydrocarbons, which decrease the oxidation cycle \u003csup\u003e\u003cspan citationid=\"CR72\" class=\"CitationRef\"\u003e72\u003c/span\u003e\u003c/sup\u003e. Different elements, such as Cl and Al, can be absorbed from the environment, particularly the marine ecosystem, on the MPs surface \u003csup\u003e\u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e73\u003c/span\u003e\u003c/sup\u003e. The high salinity of the marine environment can lead to the Na and Cl ions adsorption on the surface of MP \u003csup\u003e\u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e74\u003c/span\u003e\u003c/sup\u003e. As seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e6\u003c/span\u003e (c and f), the micrographs of MP fiber samples at an exposure time of 60 days, especially in SW samples, show high roughness of the surface and some ruptures, which can occur due to their weathering in the environment. Generally, the surfaces of MP were more susceptible to weathering in salty environments, as illustrated in former studies in China \u003csup\u003e\u003cspan citationid=\"CR75\" class=\"CitationRef\"\u003e75\u003c/span\u003e\u003c/sup\u003e and India \u003csup\u003e\u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e76\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe more irregular the MPs surface, the greater the expected absorption \u003csup\u003e\u003cspan citationid=\"CR77\" class=\"CitationRef\"\u003e77\u003c/span\u003e\u003c/sup\u003e. Moreover, irregular MPs have higher eco-toxicological impacts on living organisms \u003csup\u003e\u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e78\u003c/span\u003e\u003c/sup\u003e. The contaminants concentration, such as heavy metals, on the MPs surface mainly depends on the sorption properties of polymers \u003csup\u003e\u003cspan citationid=\"CR79\" class=\"CitationRef\"\u003e79\u003c/span\u003e\u003c/sup\u003e. In determining the capacities of adsorption, the weathering processes role is more significant compared to the plastic type \u003csup\u003e\u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e80\u003c/span\u003e\u003c/sup\u003e. Weathering and polymer aging can affect the cracks on the MPs surface and lead to fragmentation into more minor MPs or NPs \u003csup\u003e\u003cspan citationid=\"CR81\" class=\"CitationRef\"\u003e81\u003c/span\u003e\u003c/sup\u003e. Various factors, for instance temperature, seawater salinity, currents and waves, winds, and microbial community composition may cause surface weathering of MPs \u003csup\u003e\u003cspan citationid=\"CR82\" class=\"CitationRef\"\u003e82\u003c/span\u003e\u003c/sup\u003e. The MPs surface for adsorption of chemical elements in the environment can be changed by weathering and physical abrasion because of increasing their surface area and formation of anionic active locations \u003csup\u003e\u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e80\u003c/span\u003e\u003c/sup\u003e. The chemical elements adsorption on MP particles increases during degradation because of their larger surface and smaller size \u003csup\u003e\u003cspan citationid=\"CR83\" class=\"CitationRef\"\u003e83\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003e3.5. Environmental risk of MFs\u003c/h2\u003e \u003cp\u003eThe PLI evaluates the MP contamination degree in different media \u003csup\u003e\u003cspan citationid=\"CR84\" class=\"CitationRef\"\u003e84\u003c/span\u003e\u003c/sup\u003e. The status of MF contamination released from CF samples into different water is displayed in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e7\u003c/span\u003e (a). The calculated PLI values released from CFs into the water in the lab and under solar light environments were greater than 30, which indicates severe pollution (hazard category IV). In accordance with the results of this study, the PLI values of MPs in the seawater \u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e, coastal sediment \u003csup\u003e\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e\u003c/sup\u003e, and urban runoff \u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e showed severe pollution. The evaluated RQ values of CF samples are also illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e7\u003c/span\u003e (b). The values of RQ were greater than 1 that indicated a high risk. This study's findings agreed with the results of a former study on the Persian Gulf seawater and ballast water \u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e. The RQ levels of MP particles in the samples of surface water collected from the Yongjiang River, China, were also investigated, and a high risk was demonstrated \u003csup\u003e\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003ePlastic products can release MP particles and chemical additives in the environment, threatening human health \u003csup\u003e\u003cspan citationid=\"CR85\" class=\"CitationRef\"\u003e85\u003c/span\u003e\u003c/sup\u003e. Sunlight and heat can lead to the weathering of MP particles in the aquatic and terrestrial environments, resulting in the hazardous additives release \u003csup\u003e\u003cspan citationid=\"CR86\" class=\"CitationRef\"\u003e86\u003c/span\u003e\u003c/sup\u003e. In addition, MPs may absorb different contaminants, for instance persistent organic pollutants (POPs) \u003csup\u003e\u003cspan citationid=\"CR87\" class=\"CitationRef\"\u003e87\u003c/span\u003e\u003c/sup\u003e and heavy metals \u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR88\" class=\"CitationRef\"\u003e88\u003c/span\u003e\u003c/sup\u003e from the environment, therefore increasing their toxic impacts on the water organisms \u003csup\u003e\u003cspan citationid=\"CR89\" class=\"CitationRef\"\u003e89\u003c/span\u003e\u003c/sup\u003e. However, the effect of MP shape and size is also considerable in MP environmental eco-toxicological and bio-reactivity impacts \u003csup\u003e\u003cspan citationid=\"CR90\" class=\"CitationRef\"\u003e90\u003c/span\u003e\u003c/sup\u003e. The eco-toxicological effects of environmental MFs released from CBs or CFs, particularly cellulose acetate, remain largely unknown and should be addressed in future studies.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003e3.6. MFs Emission rate through CBs into water environments\u003c/h2\u003e \u003cp\u003eMFs release through CFs into aquatic ecosystems, given the large number of CFs littered into the environment worldwide, can be a special ecological concern. So far, there has been no evaluation of the transmission of MFs through CFs to the aquatic environment worldwide. In this study, by considering the mean levels of MFs released from CF samples into the water at different contact times (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e2\u003c/span\u003e and Table S3) and the mass of discarded CFs every year globally (~\u0026thinsp;845000 tons) \u003csup\u003e\u003cspan citationid=\"CR91\" class=\"CitationRef\"\u003e91\u003c/span\u003e\u003c/sup\u003e, the number of released MFs into the aquatic environment on a worldwide scale was estimated. As presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e8\u003c/span\u003e, CFs may release 14\u0026times;10\u003csup\u003e12\u003c/sup\u003e, 19\u0026times;10\u003csup\u003e12\u003c/sup\u003e, 24\u0026times;10\u003csup\u003e12\u003c/sup\u003e, 32\u0026times;10\u003csup\u003e12\u003c/sup\u003e, 38\u0026times;10\u003csup\u003e12\u003c/sup\u003e, and 51\u0026times;10\u003csup\u003e12\u003c/sup\u003e MFs into aquatic environments within 1, 2, 7, 15, 30, and 60 days of exposure, respectively. In former studies, other contaminants emission rate via CBs, including metal (loid)s \u003csup\u003e\u003cspan citationid=\"CR92\" class=\"CitationRef\"\u003e92\u003c/span\u003e\u003c/sup\u003e, BTEX \u003csup\u003e\u003cspan citationid=\"CR93\" class=\"CitationRef\"\u003e93\u003c/span\u003e\u003c/sup\u003e, PAHs \u003csup\u003e\u003cspan citationid=\"CR94\" class=\"CitationRef\"\u003e94\u003c/span\u003e\u003c/sup\u003e, aromatic amines \u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e, and nicotine \u003csup\u003e\u003cspan citationid=\"CR95\" class=\"CitationRef\"\u003e95\u003c/span\u003e\u003c/sup\u003e, leached from CBs into aquatic environments have been estimated and reported. Thus, further studies are needed to elucidate the factors, which may affect the toxic contaminants release via CBs into various ecosystems as well as specify the long-term release burden.\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Limitations","content":"\u003cp\u003eThe present study had uncertainties and limitations in evaluating the level, size, and polymer types of released MFs from CF samples. No study provides quantitative data on the presence of MFs released from CFs or CBs, preventing a detailed evaluation of the occurrence profiles of MFs in the environment. As an important subject, there are no standard methods for identifying MPs, reducing the comparability between various studies. The typical method for quantifying MFs primarily focuses on determining MPs number but not the mass. Only MFs larger than 20 \u0026micro;m were identified by visual identification in this study, and this can be the major limitation of this research that led to vastly underestimating the number of released MPs via CFs. Quantitation of MFs mass can provide valuable data to understand the levels of MFs, especially small-size MFs (\u0026lt;\u0026thinsp;20 \u0026micro;m), which cannot be detected by visual identification. Another limitation of this research was the analysis of MF types, as not all suspected MF particles were analyzed by micro-Raman because of the high number of detected particles. This can create some degree of uncertainty. Furthermore, no uniform standard models exist for ecological and health risk assessment of MPs.\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eThis research reported the occurrence and ecological risk of MFs released from CFs into the water environment under the impact of different factors, including cigarette brand, type of water, environmental condition, and exposure times. The highest MFs were observed in SW under OE conditions at an exposure time of 60 days. MFs were mainly featured with sizes ranging from 20\u0026ndash;50 \u0026micro;m. In terms of polymer types, cellulose acetate was the predominant one. The risk assessment results indicated potential ecological risk. According to the findings of this research, MFs release from CFs into the aquatic environment and may adversely affect the ecosystem. Further studies on the release of related contaminants with MFs via CB litters and the effects of various factors, for example organic/inorganic contents, temperature, salinity, and pH of aquatic environments, on the release of MFs from CFs are needed. Also, the mechanisms of MF migration from CFs into different water matrices are unclear, and further research on MFs is needed to elucidate the potential long-term consequences for ecosystem health. Finally, social/political actions must focus on performing effective strategies of waste management to restrict the entry of CB waste as a source of different contaminants, such as MFs and related toxic compounds, into beaches to ensure the conservation of aquatic ecosystems.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors are grateful to the Bushehr University of Medical Sciences for their financial support (grant No.\u0026nbsp;2517) and the Systems Environmental Health and Energy Research Center, The Persian Gulf Biomedical Science Research Institute's laboratory staff for their cooperation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAzam Mohammadi: Formal Analysis, Investigation, Methodology, Software, Writing original draft, Writing-review \u0026amp; editing; Farkhondeh Bahrani: Investigation, Writing-review \u0026amp; editing; Gabriel E. De-la-Torre: Writing-review \u0026amp; editing; Reza Saeedi: Writing-review \u0026amp; editing; Gerrit Renner: Formal Analysis, Methodology, Software, Writing-review \u0026amp; editing; Torsten C. Schmidt: Conceptualization, Writing-review \u0026amp; editing; Sina Dobaradaran: Supervision, Conceptualization, Methodology, Writing-review \u0026amp; editing, Funding acquisition.\u0026nbsp;All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated and analyzed during the current study were available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics declarations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eBelzagui F, Buscio V, Guti\u0026eacute;rrez-Bouz\u0026aacute;n C, Vilaseca M. Cigarette butts as a microfiber source with a microplastic level of concern. Science of The Total Environment 2021;762:144165.\u003c/li\u003e\n \u003cli\u003eMendes DS, Silva DNN, Santiago LEP, Gomes VJC, Beasley CR, Fernandes MEB. Comprehensive risk assessment of microplastics in tidal channel sediments in amazonian mangroves (northern Brazil). Journal of Environmental Management 2024;366:121826.\u003c/li\u003e\n \u003cli\u003eHassan I, Sethupathi S, Bashir MJ, Munusamy Y, Chan CW. A systematic review of microplastics occurrence, characteristics, identification techniques and removal methods in ASEAN and its future prospects. Journal of Environmental Chemical Engineering 2024:112305.\u003c/li\u003e\n \u003cli\u003eKhedre AM, Ramadan SA, Ashry A, Alaraby M. Abundance and risk assessment of microplastics in water, sediment, and aquatic insects of the Nile River. Chemosphere 2024;353:141557.\u003c/li\u003e\n \u003cli\u003eYadav N, Hakkarainen M. Degradable or not? Cellulose acetate as a model for complicated interplay between structure, environment and degradation. Chemosphere 2021;265:128731.\u003c/li\u003e\n \u003cli\u003eGe J, Li H, Liu P, Zhang Z, Ouyang Z, Guo X. Review of the toxic effect of microplastics on terrestrial and aquatic plants. Science of the Total Environment 2021;791:148333.\u003c/li\u003e\n \u003cli\u003eYang L, Qiao F, Lei K, et al. Microfiber release from different fabrics during washing. Environmental Pollution 2019;249:136-143.\u003c/li\u003e\n \u003cli\u003eMishra S, charan Rath C, Das AP. Marine microfiber pollution: a review on present status and future challenges. Marine pollution bulletin 2019;140:188-197.\u003c/li\u003e\n \u003cli\u003eDobaradaran S, Schmidt TC, Nabipour I, et al. Characterization of plastic debris and association of metals with microplastics in coastline sediment along the Persian Gulf. Waste management 2018;78:649-658.\u003c/li\u003e\n \u003cli\u003eBronzo L, Lusher AL, Sch\u0026oslash;yen M, Morigi C. Accumulation and distribution of microplastics in coastal sediments from the inner Oslofjord, Norway. Marine pollution bulletin 2021;173:113076.\u003c/li\u003e\n \u003cli\u003eHajiouni S, Mohammadi A, Ramavandi B, et al. Occurrence of microplastics and phthalate esters in urban runoff: a focus on the Persian Gulf coastline. Science of the Total Environment 2022;806:150559.\u003c/li\u003e\n \u003cli\u003eTreilles R, Gasperi J, Gallard A, et al. Microplastics and microfibers in urban runoff from a suburban catchment of Greater Paris. Environmental pollution 2021;287:117352.\u003c/li\u003e\n \u003cli\u003eMohammadi A, Malakootian M, Dobaradaran S, Hashemi M, Jaafarzadeh N, De-la-Torre GE. Occurrence and ecological risks of microplastics and phthalate esters in organic solid wastes: In a landfill located nearby the Persian Gulf. Chemosphere 2023;332:138910.\u003c/li\u003e\n \u003cli\u003eTan M, Sun Y, Gui J, et al. Distribution characteristics of microplastics in typical organic solid wastes and their biologically treated products. Science of the Total Environment 2022;852:158440.\u003c/li\u003e\n \u003cli\u003eMohammadi A, Malakootian M, Dobaradaran S, Hashemi M, Jaafarzadeh N. Occurrence, seasonal distribution, and ecological risk assessment of microplastics and phthalate esters in leachates of a landfill site located near the marine environment: Bushehr port, Iran as a case. Science of The Total Environment 2022;842:156838.\u003c/li\u003e\n \u003cli\u003eSu Y, Zhang Z, Wu D, Zhan L, Shi H, Xie B. Occurrence of microplastics in landfill systems and their fate with landfill age. Water research 2019;164:114968.\u003c/li\u003e\n \u003cli\u003eKashfi FS, Ramavandi B, Arfaeinia H, et al. Occurrence and exposure assessment of microplastics in indoor dusts of buildings with different applications in Bushehr and Shiraz cities, Iran. Science of The Total Environment 2022;829:154651.\u003c/li\u003e\n \u003cli\u003eSoltani NS, Taylor MP, Wilson SP. International quantification of microplastics in indoor dust: prevalence, exposure and risk assessment. Environmental Pollution 2022;312:119957.\u003c/li\u003e\n \u003cli\u003eAkhbarizadeh R, Dobaradaran S, Torkmahalleh MA, Saeedi R, Aibaghi R, Ghasemi FF. Suspended fine particulate matter (PM2. 5), microplastics (MPs), and polycyclic aromatic hydrocarbons (PAHs) in air: their possible relationships and health implications. Environmental Research 2021;192:110339.\u003c/li\u003e\n \u003cli\u003eLiao Z, Ji X, Ma Y, et al. Airborne microplastics in indoor and outdoor environments of a coastal city in Eastern China. Journal of Hazardous Materials 2021;417:126007.\u003c/li\u003e\n \u003cli\u003eZendehboudi A, Mohammadi A, Dobaradaran S, et al. Analysis of microplastics in ships ballast water and its ecological risk assessment studies from the Persian Gulf. Marine Pollution Bulletin 2024;198:115825.\u003c/li\u003e\n \u003cli\u003eSu Q, Li Y, Lu N, et al. Abundance, characteristics and ecological risk assessment of microplastics in ship ballast water in ports around Liaodong Peninsula, China. Marine Pollution Bulletin 2024;207:116812.\u003c/li\u003e\n \u003cli\u003eAra\u0026uacute;jo MCB, Costa MF. A critical review of the issue of cigarette butt pollution in coastal environments. Environmental research 2019;172:137-149.\u003c/li\u003e\n \u003cli\u003eEl Fadili H, Ben Ali M, El Mahi M, Lotfi EM. Turning Cigarette Butts (CBs) into Valuable Resources: Technical Potential and Drawbacks. Functionalized Cellulose Materials: Sustainable Manufacturing and Applications: Springer, 2025: 213-228.\u003c/li\u003e\n \u003cli\u003eDobaradaran S, Mutke XA, Schmidt TC, Swiderski P, De-la-Torre GE, Jochmann MA. Aromatic amines contents of cigarette butts: fresh and aged cigarette butts vs unsmoked cigarette. Chemosphere 2022;301:134735.\u003c/li\u003e\n \u003cli\u003eSoleimani F, Dobaradaran S, De-la-Torre GE, Schmidt TC, Saeedi R. Content of toxic components of cigarette, cigarette smoke vs cigarette butts: A comprehensive systematic review. Science of the Total Environment 2022;813:152667.\u003c/li\u003e\n \u003cli\u003eJoly F-X, Coulis M. Comparison of cellulose vs. plastic cigarette filter decomposition under distinct disposal environments. Waste Management 2018;72:349-353.\u003c/li\u003e\n \u003cli\u003eShen M, Li Y, Song B, Zhou C, Gong J, Zeng G. Smoked cigarette butts: Unignorable source for environmental microplastic fibers. Science of the Total Environment 2021;791:148384.\u003c/li\u003e\n \u003cli\u003eHidalgo-Ruz V, Gutow L, Thompson RC, Thiel M. Microplastics in the marine environment: a review of the methods used for identification and quantification. Environmental science \u0026amp; technology 2012;46:3060-3075.\u003c/li\u003e\n \u003cli\u003eMiller EA, Yamahara KM, French C, Spingarn N, Birch JM, Van Houtan KS. A Raman spectral reference library of potential anthropogenic and biological ocean polymers. Scientific Data 2022;9:780.\u003c/li\u003e\n \u003cli\u003eTomlinson D, Wilson J, Harris C, Jeffrey D. Problems in the assessment of heavy-metal levels in estuaries and the formation of a pollution index. Helgol\u0026auml;nder meeresuntersuchungen 1980;33:566-575.\u003c/li\u003e\n \u003cli\u003eXu P, Peng G, Su L, Gao Y, Gao L, Li D. Microplastic risk assessment in surface waters: A case study in the Changjiang Estuary, China. Marine pollution bulletin 2018;133:647-654.\u003c/li\u003e\n \u003cli\u003eUddin S, Fowler SW, Saeed T. Microplastic particles in the Persian/Arabian Gulf\u0026ndash;a review on sampling and identification. Marine pollution bulletin 2020;154:111100.\u003c/li\u003e\n \u003cli\u003eEveraert G, Van Cauwenberghe L, De Rijcke M, et al. Risk assessment of microplastics in the ocean: Modelling approach and first conclusions. Environmental pollution 2018;242:1930-1938.\u003c/li\u003e\n \u003cli\u003eZhang X, Leng Y, Liu X, Huang K, Wang J. Microplastics\u0026rsquo; pollution and risk assessment in an urban river: a case study in the Yongjiang River, Nanning City, South China. Exposure and Health 2020;12:141-151.\u003c/li\u003e\n \u003cli\u003eAndrady AL. Microplastics in the marine environment. Marine pollution bulletin 2011;62:1596-1605.\u003c/li\u003e\n \u003cli\u003eCashman MA, Langknecht T, El Khatib D, et al. Quantification of microplastics in sediments from Narragansett Bay, Rhode Island USA using a novel isolation and extraction method. Marine pollution bulletin 2022;174:113254.\u003c/li\u003e\n \u003cli\u003eLaycock B, Nikolić M, Colwell JM, et al. Lifetime prediction of biodegradable polymers. Progress in Polymer Science 2017;71:144-189.\u003c/li\u003e\n \u003cli\u003eChamas A, Moon H, Zheng J, et al. Degradation rates of plastics in the environment. ACS Sustainable Chemistry \u0026amp; Engineering 2020;8:3494-3511.\u003c/li\u003e\n \u003cli\u003eGewert B, Plassmann M, Sandblom O, MacLeod M. Identification of chain scission products released to water by plastic exposed to ultraviolet light. Environmental Science \u0026amp; Technology Letters 2018;5:272-276.\u003c/li\u003e\n \u003cli\u003eDe Fenzo A, Giordano M, Sansone L. A clean process for obtaining high-quality cellulose acetate from cigarette butts. Materials 2020;13:4710.\u003c/li\u003e\n \u003cli\u003eLuo H, Tu C, He D, et al. Interactions between microplastics and contaminants: A review focusing on the effect of aging process. Science of the Total Environment 2023:165615.\u003c/li\u003e\n \u003cli\u003eZambrano MC, Pawlak JJ, Daystar J, Ankeny M, Cheng JJ, Venditti RA. Microfibers generated from the laundering of cotton, rayon and polyester based fabrics and their aquatic biodegradation. Marine pollution bulletin 2019;142:394-407.\u003c/li\u003e\n \u003cli\u003eJiang Y, Zhao Y, Wang X, Yang F, Chen M, Wang J. Characterization of microplastics in the surface seawater of the South Yellow Sea as affected by season. Science of the Total Environment 2020;724:138375.\u003c/li\u003e\n \u003cli\u003eYadav N, Hakkarainen M. Degradation of Cellulose Acetate in Simulated Aqueous Environments: One‐Year Study. Macromolecular Materials and Engineering 2022;307:2100951.\u003c/li\u003e\n \u003cli\u003eSuhrhoff TJ, Scholz-B\u0026ouml;ttcher BM. Qualitative impact of salinity, UV radiation and turbulence on leaching of organic plastic additives from four common plastics\u0026mdash;A lab experiment. Marine pollution bulletin 2016;102:84-94.\u003c/li\u003e\n \u003cli\u003eZhang P, Huang P, Sun H, Ma J, Li B. The structure of agricultural microplastics (PT, PU and UF) and their sorption capacities for PAHs and PHE derivates under various salinity and oxidation treatments. Environmental pollution 2020;257:113525.\u003c/li\u003e\n \u003cli\u003eNaik RK, Chakraborty P, D\u0026rsquo;Costa PM, Anilkumar N, Mishra R, Fernandes V. A simple technique to mitigate microplastic pollution and its mobility (via ballast water) in the global ocean. Environmental Pollution 2021;283:117070.\u003c/li\u003e\n \u003cli\u003eFred-Ahmadu OH, Bhagwat G, Oluyoye I, Benson NU, Ayejuyo OO, Palanisami T. Interaction of chemical contaminants with microplastics: Principles and perspectives. Science of the Total Environment 2020;706:135978.\u003c/li\u003e\n \u003cli\u003eZepnik S, Kabasci S, Radusch H-J. Influence of external plasticization on rheological and thermal properties of cellulose acetate with respect to its foamability. 2012.\u003c/li\u003e\n \u003cli\u003eErtaş A, G\u0026ouml;k\u0026ccedil;e B, T\u0026uuml;ney İ. Risk assessment of cigarette butts and microplastic pollution in a drinking and irrigation water basin of West Anatolia, T\u0026uuml;rkiye. Environmental Monitoring and Assessment 2024;196:676.\u003c/li\u003e\n \u003cli\u003eGholizadeh M, Shadi A, Abadi A, et al. Exploring the microplastic pollution: Unveiling origins and varieties in coastal sediments and waters of the Bushehr Province, Persian Gulf, Iran. Marine Pollution Bulletin 2024;198:115939.\u003c/li\u003e\n \u003cli\u003eAlimba CG, Faggio C. Microplastics in the marine environment: Current trends in environmental pollution and mechanisms of toxicological profile. Environmental toxicology and pharmacology 2019;68:61-74.\u003c/li\u003e\n \u003cli\u003eS\u0026oslash;rensen L, Groven AS, Hovsbakken IA, et al. UV degradation of natural and synthetic microfibers causes fragmentation and release of polymer degradation products and chemical additives. Science of the Total Environment 2021;755:143170.\u003c/li\u003e\n \u003cli\u003eEerkes-Medrano D, Leslie HA, Quinn B. Microplastics in drinking water: A review and assessment. Current Opinion in Environmental Science \u0026amp; Health 2019;7:69-75.\u003c/li\u003e\n \u003cli\u003eSimon-S\u0026aacute;nchez L, Vianello A, Kirstein IV, Molazadeh M-S, Lorenz C, Vollertsen J. Assessment of microplastic pollution and polymer risk in the sediment compartment of the Limfjord, Denmark. Science of the Total Environment 2024;950:175017.\u003c/li\u003e\n \u003cli\u003eWright SL, Kelly FJ. Plastic and human health: a micro issue? Environmental science \u0026amp; technology 2017;51:6634-6647.\u003c/li\u003e\n \u003cli\u003eFoley CJ, Feiner ZS, Malinich TD, H\u0026ouml;\u0026ouml;k TO. A meta-analysis of the effects of exposure to microplastics on fish and aquatic invertebrates. Science of the total environment 2018;631:550-559.\u003c/li\u003e\n \u003cli\u003eBian P, Liu Y, Zhao K, et al. Spatial variability of microplastic pollution on surface of rivers in a mountain-plain transitional area: A case study in the Chin Ling-Wei River Plain, China. Ecotoxicology and Environmental Safety 2022;232:113298.\u003c/li\u003e\n \u003cli\u003eHamzah SR, Anuar ST, Khalik WMAWM, Kolandhasamy P, Ibrahim YS. Ingestion of microplastics by the estuarine polychaete, Namalycastis sp. in the Setiu Wetlands, Malaysia. Marine pollution bulletin 2021;170:112617.\u003c/li\u003e\n \u003cli\u003eTaghipour H, Ghayebzadeh M, Mousavi SMS, Sharifi H, Payandeh A. Incidence and exposure to microplastics in table salt present in the Iran market. Toxicology Reports 2023;11:129-140.\u003c/li\u003e\n \u003cli\u003ePriyambada G, Kurniawan B, Sitompul RG, Darmayanti L. The abundance of microplastics in Siak tributary sediments in the watershed area, Pekanbaru City, Riau (Case Study Sago River). Materials Today: Proceedings 2023;87:272-277.\u003c/li\u003e\n \u003cli\u003eNovotny TE, Hamzai L. Cellulose acetate cigarette filter is hazardous to human health. BMJ Publishing Group Ltd, 2024.\u003c/li\u003e\n \u003cli\u003eFong J, Lee SHR, Sun Y, et al. Litter traps: A comparison of four marine habitats as sinks for anthropogenic marine macro-litter in Singapore. Marine Pollution Bulletin 2023;196:115645.\u003c/li\u003e\n \u003cli\u003eBridson JH, Patel M, Lewis A, Gaw S, Parker K. Microplastic contamination in Auckland (New Zealand) beach sediments. Marine Pollution Bulletin 2020;151:110867.\u003c/li\u003e\n \u003cli\u003eMurphy L, Germaine K, Kakouli-Duarte T, Cleary J. Assessment of microplastics in Irish river sediment. Heliyon 2022;8.\u003c/li\u003e\n \u003cli\u003eD\u0026iacute;az-Mendoza C, Mouthon-Bello J, Botero CM, Acevedo-Barrios R, Guti\u0026eacute;rrez L. Microbiological analysis of cigarette butts and cigarette butt fibers on a tourist beach in Cartagena, Colombia. Scientific Reports 2025;15:14510.\u003c/li\u003e\n \u003cli\u003eGregor-Svetec D. Polymers in printing filaments. Polymers for 3D printing: Elsevier, 2022: 155-269.\u003c/li\u003e\n \u003cli\u003eRamadan AM, Gomaa AZ, Abdallah MA. Preparation and Evaluation of Polyamides for Printing Ink. Egyptian Journal of Chemistry 2020;63:1639-1653.\u003c/li\u003e\n \u003cli\u003eLamb JV, Buffet J-C, Turner ZR, Khamnaen T, O\u0026rsquo;Hare D. Metallocene polyethylene wax synthesis. Macromolecules 2020;53:5847-5856.\u003c/li\u003e\n \u003cli\u003edo Sul JAI, Costa MF. The present and future of microplastic pollution in the marine environment. Environmental pollution 2014;185:352-364.\u003c/li\u003e\n \u003cli\u003eBolgar M, Hubball J, Groeger J, Meronek S. Handbook for the chemical analysis of plastic and polymer additives: CRC Press, 2007.\u003c/li\u003e\n \u003cli\u003eKarami A, Golieskardi A, Choo CK, Larat V, Karbalaei S, Salamatinia B. Microplastic and mesoplastic contamination in canned sardines and sprats. Science of the total environment 2018;612:1380-1386.\u003c/li\u003e\n \u003cli\u003eBhatnagar A, Devi P. Water quality guidelines for the management of pond fish culture. International journal of environmental sciences 2013;3:1980-2009.\u003c/li\u003e\n \u003cli\u003eGao L, Fu D, Zhao J, et al. Microplastics aged in various environmental media exhibited strong sorption to heavy metals in seawater. Marine Pollution Bulletin 2021;169:112480.\u003c/li\u003e\n \u003cli\u003eVeerasingam S, Saha M, Suneel V, et al. Characteristics, seasonal distribution and surface degradation features of microplastic pellets along the Goa coast, India. Chemosphere 2016;159:496-505.\u003c/li\u003e\n \u003cli\u003eRazanajatovo RM, Ding J, Zhang S, Jiang H, Zou H. Sorption and desorption of selected pharmaceuticals by polyethylene microplastics. Marine pollution bulletin 2018;136:516-523.\u003c/li\u003e\n \u003cli\u003eSchwarzer M, Brehm J, Vollmer M, et al. Shape, size, and polymer dependent effects of microplastics on Daphnia magna. Journal of Hazardous Materials 2022;426:128136.\u003c/li\u003e\n \u003cli\u003eVetrimurugan E, Jonathan M, Sarkar S, et al. Occurrence, distribution and provenance of micro plastics: A large scale quantitative analysis of beach sediments from southeastern coast of South Africa. Science of the Total Environment 2020;746:141103.\u003c/li\u003e\n \u003cli\u003eHolmes LA, Turner A, Thompson RC. Interactions between trace metals and plastic production pellets under estuarine conditions. Marine Chemistry 2014;167:25-32.\u003c/li\u003e\n \u003cli\u003eZheng Y, Hamed M, De-la-Torre GE, et al. Holes on surfaces of the weathered plastic fragments from coastal beaches. Marine Pollution Bulletin 2023;193:115180.\u003c/li\u003e\n \u003cli\u003eArp HPH, Kühnel D, Rummel C, et al. Weathering plastics as a planetary boundary threat: exposure, fate, and hazards. Environmental science \u0026amp; technology 2021;55:7246-7255.\u003c/li\u003e\n \u003cli\u003eTorres FG, Dioses-Salinas DC, Pizarro-Ortega CI, De-la-Torre GE. Sorption of chemical contaminants on degradable and non-degradable microplastics: Recent progress and research trends. Science of the Total Environment 2021;757:143875.\u003c/li\u003e\n \u003cli\u003eShekoohiyan S, Akbarzadeh A. The abundance of microplastic pollution along the Jajroud river of Tehran: estimating the water quality index and the ecological risk. Ecological Indicators 2022;145:109629.\u003c/li\u003e\n \u003cli\u003eLiu Y, Li Z, Jal\u0026oacute;n-Rojas I, et al. Assessing the potential risk and relationship between microplastics and phthalates in surface seawater of a heavily human-impacted metropolitan bay in northern China. Ecotoxicology and Environmental Safety 2020;204:111067.\u003c/li\u003e\n \u003cli\u003eRanjani M, Veerasingam S, Venkatachalapathy R, et al. Assessment of potential ecological risk of microplastics in the coastal sediments of India: a meta-analysis. Marine Pollution Bulletin 2021;163:111969.\u003c/li\u003e\n \u003cli\u003eTan X, Yu X, Cai L, Wang J, Peng J. Microplastics and associated PAHs in surface water from the Feilaixia Reservoir in the Beijiang River, China. Chemosphere 2019;221:834-840.\u003c/li\u003e\n \u003cli\u003eKim D, Chae Y, An Y-J. Mixture toxicity of nickel and microplastics with different functional groups on Daphnia magna. Environmental science \u0026amp; technology 2017;51:12852-12858.\u003c/li\u003e\n \u003cli\u003eMai Y, Peng S, Lai Z, Wang X. Measurement, quantification, and potential risk of microplastics in the mainstream of the Pearl River (Xijiang River) and its estuary, Southern China. Environmental Science and Pollution Research 2021;28:53127-53140.\u003c/li\u003e\n \u003cli\u003eBucci K, Rochman CM. Microplastics: a multidimensional contaminant requires a multidimensional framework for assessing risk. Microplastics and Nanoplastics 2022;2:7.\u003c/li\u003e\n \u003cli\u003eCarlozo L. Cigarettes: 1.7 billion pounds of trash. Chicago Tribune 2008;18.\u003c/li\u003e\n \u003cli\u003eAkhbarizadeh R, Dobaradaran S, Parhizgar G, Schmidt TC, Mallaki R. Potentially toxic elements leachates from cigarette butts into different types of water: a threat for aquatic environments and ecosystems? Environmental research 2021;202:111706.\u003c/li\u003e\n \u003cli\u003eDobaradaran S, Schmidt TC, Kaziur-Cegla W, Jochmann MA. BTEX compounds leachates from cigarette butts into water environment: a primary study. Environmental Pollution 2021;269:116185.\u003c/li\u003e\n \u003cli\u003eDobaradaran S, Schmidt TC, Lorenzo-Parodi N, et al. Cigarette butts: an overlooked source of PAHs in the environment? Environmental pollution 2019;249:932-939.\u003c/li\u003e\n \u003cli\u003eDobaradaran S, Telgheder U, De-la-Torre GE, Rockel SP, Mutke XA, Schmidt TC. Elucidating nicotine transfer into water environments via cigarette butt remaining parts. Environmental Pollution 2024;341:122943.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Cellulose acetate, Cigarette butt, Contamination, Marine environment, Microplastics, Risk assessment.","lastPublishedDoi":"10.21203/rs.3.rs-6860318/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6860318/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eCigarette butts (CBs) are known as one of the most prevalent forms of environmental waste, needing global attention to mitigate their detrimental health and ecological impacts. Owing to their filter composition, discarded CBs can persistently release microfibers (MFs) into the environment. In this research, the levels, characteristics, and ecological risks associated with MFs released from cigarette filters (CFs) into water (distilled and seawater) were investigated under various environmental conditions (laboratory and outdoor settings). The assessment focused on short-term exposure durations of 1, 2, 7, 15, 30, and 60 days, forming the initial phase of this research. The mean level of released MFs ranged from 5.78-92.43 items/g CFs. The results highlighted that more MFs were released from CFs into the seawater and outdoor environment at a contact time of 60 days. The predominant size and color of the released MFs were 20-50 µm and white/transparent, respectively. The main detected polymer composition of MFs was cellulose acetate. The computed pollution load index (PLI) values were \u0026gt; 30, indicating severe pollution. Additionally, the risk quotient (RQ) values were greater than 1, indicating a potential threat to the water environment. Based on mean levels of released MFs through CFs during contact times of 1 to 60 days and the amount of discarded CBs yearly on a global scale, CFs can leachate14×10\u003csup\u003e12\u003c/sup\u003e-51×10\u003csup\u003e12\u003c/sup\u003e MFs into the aquatic environments. The results of present research allow scientific society to better comprehend the CFs' role in transporting MFs in the aquatic systems as well as their potential environmental risks.\u003c/p\u003e","manuscriptTitle":"Cigarette filters as a main microfibers source in aquatic environments: Phase I","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-30 09:48:02","doi":"10.21203/rs.3.rs-6860318/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-07-22T18:07:04+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-20T15:25:20+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"98415148513119956019838310767818458787","date":"2025-07-19T07:18:09+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-03T09:12:59+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"287135915348642453524316874263669075599","date":"2025-06-26T00:37:33+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-25T16:48:58+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-06-20T01:36:20+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-06-19T06:48:50+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-06-18T07:07:44+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-06-10T07:31:33+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"ac23c43e-1962-459c-82e9-2580c576f794","owner":[],"postedDate":"June 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":50615733,"name":"Earth and environmental sciences/Environmental sciences"},{"id":50615734,"name":"Physical sciences/Chemistry"}],"tags":[],"updatedAt":"2025-10-27T16:38:57+00:00","versionOfRecord":{"articleIdentity":"rs-6860318","link":"https://doi.org/10.1038/s41598-025-20771-7","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2025-10-22 16:17:11","publishedOnDateReadable":"October 22nd, 2025"},"versionCreatedAt":"2025-06-30 09:48:02","video":"","vorDoi":"10.1038/s41598-025-20771-7","vorDoiUrl":"https://doi.org/10.1038/s41598-025-20771-7","workflowStages":[]},"version":"v1","identity":"rs-6860318","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6860318","identity":"rs-6860318","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}