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Optical micrographs at different magnification of two microfibers detected on filter surface: (a) twisting and convolutions features of a natural microfiber and (b) cylindrical shape and smooth surface of a synthetic microfiber.
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Microplastics of fibrous shape are esteemed to be the most abundant micro-debris form present in the environment. Despite the occurrence of microfibers in fish may pose a risk to human health, the literature is scarce regarding studies on the contamination in commercial marine fish mostly due to methodological issues. In this study, a versatile app...
Citations
... Microfibers isolated on the filter membranes were inspected using a light microscope (M205C, Leica, Wetzlar, Germany) with a magnification of 0.78-16x ( Figure 1A), and then counted and categorized according to color. The micrographs of each microfiber were analyzed by two different operators to discriminate between synthetic and natural microfibers according to some morphological features: cross-section shape, breakages, and alterations of the fiber body, shape, and appearance of the ends (Stanton et al., 2019;Volgare et al., 2022;. The morphology of natural fibers is more complex than that of synthetic ones, as they do not show a uniform diameter and are twisted upon themselves like flat ribbons with frayed edges. ...
... In addition, the visual classification of natural and synthetic microfibers may be criticized for its susceptibility to human error. In this light, the analyses of the fiber micrographs by two different operators, the use of micrographs of some natural and synthetic microfibers as references during the observation under the microscope (Volgare et al., 2022), and the FTIR analyses of a subsample of particles may help to correctly identify microfiber types. The effort to implement a fast and easy method in the evaluation of microfiber contamination is linked to the difficulties in obtaining clear FTIR spectra from the small, often curved, surfaces of textile microfibers (Stanton et al., 2019). ...
The increased demand and consumption of synthetic textiles have contributed to microplastic pollution in the form of microfibers. These particles are widely spread in the aquatic environment, leading to the exposure of marine biota, including edible species. The current study aimed to assess the extent of microfiber contamination in a commercially relevant fish species, Merluccius merluccius, which is considered a small-scale bioindicator for the monitoring of plastic ingestion in the Mediterranean coastal environment. The frequency of ingestion, abundance, and composition of textile microfibers isolated from the fish gut were characterized. Results showed the occurrence of microfibers in 75% of the samples, with a mean number of 10.6 microfibers/individual, of which 70% were classified as natural microfibers. The spectroscopic analyses confirmed both the visual identification of microfibers and the prevalence of cellulosic fibers. The obtained findings provided evidence of both natural/artificial and synthetic microfiber exposure in an important commercial fish species that, considering the consumption of small individuals without being eviscerated, may be a potential route of microfiber exposure in humans. Monitoring programs for fishery products from markets are needed to assess contamination levels and human health risks. In addition, measures to control microfiber pollution need to occur at multiple levels, from textile industries to international governments.
... al. 2019;Capillo et al. 2020;Rodríguez-Romeu et al. 2020;Macieira et al. 2021), deep-sea organisms(Taylor et al. 2016), shellfish and mussels(Santonicola et al. 2021;Volgare et al. 2022), seabirds(Provencher et al. 2018), marine mammals(Perez-Venegas et al. 2018), and several other marine invertebrate species (e.g.,Gusmão et al. 2016;Lourenço et al. 2017;Piarulli et al. 2019). Considerable numbers of microfibers, largely made of cellulosic materials, were also found in commercially important Mediterranean fish species including sardines (Sardina pilchardus), anchovies (Engraulis encrasicolus), and European hakes (Merluccius Merluccius), with this raising important concerns about food safety and human consumption of fiber-contaminated species(Compa et al. 2018;Avio et al. 2020). ...
Textile microfibers are the most commonly reported type of anthropogenic particle found by microplastic pollution surveys around the globe, often representing 80–90% of all particle counts. Significant concentrations of this emerging pollutant have been detected in most marine ecosystems surveyed to date, including sea ice, deep sea sediments, surface and subsurface waters, and coastal environments. Recent studies revealed the presence of microfibers in the digestive systems of numerous marine organisms, including seabirds, deep-sea crustaceans, and commercial fish species, as well as in both wet and dry atmospheric deposition samples. Ingestion of microfibers has been linked to negative health effects in marine invertebrates, but there is currently no evidence of harm to wild creatures exposed to environmentally relevant fiber concentrations. At the same time, we still have a very limited understanding of how they affect wild populations. Additionally, a wide range of chemicals, such as dyes, additives, and flame retardants, are employed in the manufacture of both natural and synthetic textiles, raising questions regarding the function of fibers as vectors of dangerous substances in the marine environment. This chapter aims to provide state-of-the-art information on the sources, transport, degradation, uptake, toxicity, and persistence of synthetic and natural fibers in the marine environment. Special consideration is given to sampling and analytical methods as well as to future areas for potential research.
... As also reported in other experiments, mussels' ability to accumulate microplastics, as well as to eliminate them, is not strictly correlated with the organisms' size [39]. Other studies, instead, showed a negative correlation between microfiber levels and mussel weight, which could be explained by the fact that in the Mytilus species, pumping and filtration rates decrease with higher soft tissue mass [65,66]. ...
Microplastics are an environmental pollutant increasingly present in seawater, the
spread of which also represents a threat to food safety. In fact, these particles can be ingested through various foods, among the most at risk are bivalve molluscs, as they filter large quantities of seawater and enter the diet of consumers ingested entirely. Purification studies of bivalves could allow us to understand in a more precise way the ability of organisms to eliminate microplastics, in order to test
this process as a potential method of removing such contaminants from bivalves intended for human consumption.
... In this context, intermediate screening steps have been applied to classify synthetic and natural/artificial microfibers [25]. There are key typical features that make the analysis of microfiber surface morphology an essential tool for more a confident identification of microfiber particles of different origins [13,23,[25][26][27]. Rodríguez-Romeu et al. [13] characterized different microfiber typologies according to their morphological features (e.g., general and microscopic appearance). ...
... Despite the morphological analyses of synthetic textile fibers having been criticized because they are liable to human error [28], this approach was successfully applied to assess the microfiber contamination in bivalves (Mytilus galloprovincialis) [27], commercial fish species (Mullus barbatus and Engraulis encraiscolous) [13,15,29], and environmental samples [24,25], providing a feasible method to evaluate microfiber pollution along the marine ecosystem. ...
... Each microfiber isolated on the filter was photographed, and then the micrographs were analyzed by two different operators in order to differentiate synthetic and natural or artificial microfibers according to some morphological characteristics (cross-section, breakages, and the appearance of the fiber body and ends) and the flowchart proposed by Stanton et al. [25]. Prior to sample analysis, the capability of the textile fiber analyst was improved through the observation of synthetic (e.g., polyester) and natural (e.g., cotton) microfibers of known origin [25,27,35] reported in Figure 1. These micrographs were used as references to identify the microfiber morphological features used during the sample analyses. ...
Despite the wide distribution of textile microfibers in the marine environment, there is still limited knowledge on microfiber ingestion in fish species intended for human consumption, mostly due to analytical issues. The present study aims to assess the occurrence of microfibers in red mullet (Mullus barbatus) samples collected from the Italian waters of the central Adriatic Sea. M. barbatus is a bottom fish that lives in contact with sediment and therefore was proposed as a sentinel species for the monitoring plastic pollution. A visual approach based on the evaluation of specific microfiber surface morphology was applied for the identification of particles of different origins. The preliminary findings showed the presence of microfibers in 80% of red mullet samples with a mean of 5.95 microfibers/individual. The majority (>80%) of the isolated microfibers were of natural/artificial origin, while the dominant colors were blue and black. The obtained results confirmed that benthic fish species are susceptible to microfiber ingestion and indicate the high availability of these particles in the Adriatic basin. Considering the spectroscopic drawbacks in microfiber analyses and the need to improve the current knowledge on the rate of contamination of fishery products, the visual approach could be a feasible, easy, and accessible method in the study of microfiber pollution, and the assessment of consumer health risks.
... Microplastic accumulation in mussels may be related to different mechanisms, such as ingestion, adherence, and fusion into the byssus [117,120]. Fibrous microplastics show a small diameter compatible with the feeding size range (around 15-30 µm) of filter-feeding organisms [121]. In addition, microfibers may be trapped in gills and hepatopancreases, resulting in a longer retention time compared with other microplastic types [110,122,123]. ...
... The currently available data showed no significant difference between the mussel sampling period and microfiber uptake [16,124], but deeper investigation is needed to better understand the physiological factors that determine the extent of microfiber exposure in bivalves. On the other hand, a negative correlation was observed between microfiber levels and mussel weight, which could be explained by the fact that in Mytilus species, pumping and filtration rates decrease with higher soft tissue mass [121,125]. ...
... The small size of these particles and the presence of dyes on the microfibers may hamper the identification using conventional spectroscopic techniques [142,143]. Moreover, the choice of appropriate substrates represents an important drawback, considering that cellulose membranes, which are frequently employed for the filtration of biological matrices, may interfere with signal detection and spectra acquisition [121]. Another important challenge is the low spectral signal intensities of natural materials, which make them more susceptible to dye interference [30]. ...
Simple Summary
Microfiber pollution is a widespread threat to marine fauna. These particles may be released into water from textiles during the washing process, and due to their low dimensions, the majority of microfibers cannot be blocked from wastewater treatment plants, reaching seas and oceans. Consequently, they could be ingested by marine organisms, including edible species, potentially leading to human exposure. However, microfiber and associated chemical exposure in fish and humans are still understudied. Further research is needed to better understand the potential negative impacts of microfibers on aquatic habitats, marine biota, and humans.
Abstract
The omnipresence of microfibers in marine environments has raised concerns about their availability to aquatic biota, including commercial fish species. Due to their tiny size and wide distribution, microfibers may be ingested by wild-captured pelagic or benthic fish and farmed species. Humans are exposed via seafood consumption. Despite the fact that research on the impact of microfibers on marine biota is increasing, knowledge on their role in food security and safety is limited. The present review aims to examine the current knowledge about microfiber contamination in commercially relevant fish species, their impact on the marine food chain, and their probable threat to consumer health. The available information suggests that among the marine biota, edible species are also contaminated, but there is an urgent need to standardize data collection methods to assess the extent of microfiber occurrence in seafood. In this context, natural microfibers should also be investigated. A multidisciplinary approach to the microfiber issue that recognizes the interrelationship and connection of environmental health with that of animals and humans should be used, leading to the application of strategies to reduce microfiber pollution through the control of the sources and the development of remediation technologies.
... Potential synthetic fibers were classified from natural according to some morphological characteristics and counted (Figure 1). In addition, the micrographs of some MFs both natural (e.g., wool, cotton) and synthetic (e.g., polyester, polyamide) were used as references during the observation under the microscope (Volgare et al., 2022). ...
... FTIR spectroscopy corroborated the correct visual classification by fiber morphology, allowing to identify different typologies of polymers, represented by cellulose, cotton and polyester (Figure 2). However, the number of MFs examined to confirm the optical microscopy identification (Zhu et al., 2019;Volgare et al., 2022) was not representative of the total MFs in the samples and, therefore, it is not possible to indicate the % for the different types of polymers identified. ...
... Several research on MP pollution were focused exclusively on plastic fragments, underestimating the number of total MPs in fish. Recently, more attention has been dedicated to the study of MF contamination showing as fibers may impact a high proportion of Mediterranean fish species, including those for human consumption (Giani et al., 2019;Rodríguez-Romeu et al., 2020;Santonicola et al., 2021;Volgare et al., 2022). ...
The ingestion of synthetic microfibers, the most prevalent type of microplastics in marine environments, and natural fibers was assessed in Engraulis engrasicolus and Mullus barbatus, two commercially important fish species in the Mediterranean Sea. Microfibers were isolated from the fish gastrointestinal tract using a 10% potassium hydroxide solution. For the microfiber characterization, the evaluation of specific morphological features using a light microscope, coupled with the Fourier-transform infrared (FTIR) analysis of a subsample of isolated particles, was applied. The preliminary results showed the occurrence of microfibers in 53 and 60% of European anchovy and Red mullet, respectively. A mean of 6.9 microfibers/individual was detected in anchovies, while on average Red mullet samples contained 9.2 microfibers/individual. The most common colors of fibers in both species were black, blue, and transparent. Visual characterization of fibers allowed the classification of 40% of the items as synthetic microfibers. FTIR spectroscopy confirmed the visual classification by fiber morphology. Microfibers were made of different typologies of polymers, represented by cellulose, cotton, and polyester. These findings confirm as the wide distribution of fibrous microplastics, and natural microfibers may impact both pelagic and deep-sea trophic webs. Despite the presence of microfibers in fish species poses a potential risk to human health, the literature is scarce regarding studies on the uptake by commercial marine fish mostly due to methodological issues. The visual characterization, corroborated by spectroscopic techniques, may be useful to differentiate synthetic and natural fibers, representing a fast and easy method to assess fibrous microplastic pollution in commercially important fish species.
... 47 In farmed mussels from the Mediterranean Sea M. galloprovincialis) synthetic and natural textile microfibers (an average of 14.5720 microfibres per individual) have been documented with cotton and wool as the majority (54% and of 985.14 μm in length) raising concerns due recent reports on neurotoxicity, oxidative stress and metabolic and developmental disorders . 48,49 Up to now, no information is available on the effects of nanoscale natural fibers although fragmentation below 100nm could naturally occur and more likely in areas receiving higher amounts as along marine coasts. With the aim to fulfill such a knowledge gap, here we investigate the uptake and biological effects of NC fibers, in the marine mussel M. ...
... 82 Xenobiotic metabolism can also enhance ROS formation but the nature of this stressor is not likely to induce these mechanistic defenses nor was any interference observed in the metabolic capacity as a consequence of NC exposures at catalytic level. 48 It can thus be stated, on the results presented above, the fibers were likely unable to enter the cells, because neither changes on oxidative stress nor enzymes involved in biotransformation were observed. ...
The growing application of nanocellulose in various industrial sectors with potential release into the natural environment demands for safety assessment and thus ecotoxicity. Here we tested two types of cellulose...
