Detection of fibrous microplastics and natural microfibers in fish species (Engraulis encrasicolus, Mullus barbatus and Merluccius merluccius) for human consumption from the Tyrrhenian sea.

The occurrence of natural/artificial and synthetic microfibers was assessed in three commercial fish species (Engraulis encrasicolus, Mullus barbatus, Merluccius merluccius) from the Tyrrhenian Sea sold for human consumption. The gastrointestinal tracts of n. 150 samples were analyzed, the isolated microfibers were classified applying a morphological approach, based on the analysis of their morphological features, coupled with the identification of the chemical composition of a subsample of microfibers. All the species contained microfibers at levels ranging from 0 to 49 items/individual and the number of ingested microfibers significantly differed between pelagic and demersal fishes. The evaluation of fiber morphologies highlighted that natural/artificial microfibers were the most numerous among the isolated microfibers, while the dominant colors were blue, black, and clear in all the species. Chemical characterization confirmed the morphological identification and indicated cellulose and polyester as the most common polymer types. Considering the analytical issues that may affect the evaluation of microfiber pollution, the results pointed out the importance of an accurate morphological approach that allows the distinction between different fiber types, before the spectroscopic analyses. Moreover, the implementation of fast and accessible methods to identify microfibers in fish species intended for human consumption will be beneficial also to make an adequate risk assessment to consumer health.

Microplastic contamination in the agri-food chain: The case of honeybees and beehive products.

Microplastics, MPs, plastic fragments with a dimension lower than 5 mm, and microfibers, MFs, synthetic and natural/artificial fibrous fragments with a diameter lower than 50 µm, are ubiquitous pollutants identified in different environmental compartments. In this work the occurrence of MPs and MFs on honeybees, Apis mellifera, and beehive products was evaluated, using Fourier transform infrared microspectroscopy, confirming that MPs and MFs are widely present as air contaminants in all the apiary's areas (high and low urbanized areas) in Southern Italy. Results indicated that independently from the site, both honeybees and honey samples, are contaminated by MFs with non-natural color. The majority of MFs were of natural origin followed by artificial MFs and synthetic MFs. Moreover, the chemical composition of MFs isolated from honeybees reflect that used in synthetic fabrics, leading to the hypothesis that they are released from textile to air where are captured by bees. Results highlight that MFs represent a class of ubiquitous airborne anthropogenic pollutants. The identification of polytetrafluoroethylene, PTFE, MPs in honeybees confirm the recent findings that PTFE MPs are diffuse soil and air contaminants while the identification of polyethylene, PE, based MPs in honey samples, from low density urban sites, could be correlated to the large use of PE in agriculture. In the honey samples, also polycaprolactone, PCL, MPs were identified, mainly in high density urban sites, confirming that biodegradable materials could be further pollutants in the environments. The results indicate that honeybees are contaminated by MPs and MFs during their flights or picking up from the hive components, flowers, from other nest mates, from the clothes of the beekeeper, among others and some of them could be transferred to honey samples that could be also affected by soil contamination.

A study on textile microfiber contamination in the gastrointestinal tracts of Merluccius merluccius samples from the Tyrrhenian Sea.

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.

Effect of biodegradable polymers upon grazing activity of the sea urchin Paracentrotus lividus (Lmk) revealed by morphological, histological and molecular analyses.

In the last years biodegradable polymers (BPs) were largely used as real opportunity to solve plastic pollution. Otherwise, their wide use in commercial products, such as packaging sector, is causing a new pollution alarm, mainly because few data reported about their behaviour in the environment and toxicity on marine organisms. Our previous results showed that embryos of the sea urchin Paracentrotus lividus (Lmk) exposed to poly(ε-caprolactone) (PCL), poly(3-hydroxybutyrate) (PHB) and poly(lactic acid) (PLA) showed delay of their development and morphological malformations, also affecting at the molecular levels the expression of several genes involved in different functional responses. In the present work for the first time, we tested the effects of five microplastics (MPs) obtained from BPs such as PBS, poly(butylene succinate), PBSA, poly(butylene succinate-co-butylene adipate), PCL, PHB and PLA, upon grazing activity of the sea urchin revealed by: i. histological analysis seeing at the gonadic tissues; ii. morphological analysis of the deriving embryos; iii. molecular analyses on these embryos to detect variations of the gene expression of eighty-seven genes involved in stress response, detoxification, skeletogenesis, differentiation and development. All these results will help in understanding how MP accumulated inside various organs in the adult sea urchins, and more in general in marine invertebrates, could represent risks for the marine environment.

Phthalate levels in common sea anemone Actinia equina and Anemonia viridis: A proxy of short-term microplastic interaction?

Phthalates are widely employed plasticizers blended to plastic polymers that, during plastic aging and weathering are prone to leach in the surrounding environment. Thus, phthalates were proposed to indirectly evaluate MPs contamination in marine environments, with still uncertain and scarce data, particularly for wildlife. This study investigates simultaneously microplastics (MPs) and phthalates (PAEs) occurrence in wild Actinia equina and Anemonia viridis, two common and edible sea anemone species. Both species had a 100 % frequency of MPs occurrence, with similar average concentrations. PAEs were detected in 70 % of samples, with concentrations up to 150 ng/g in A. equina and 144.3 ng/g for A. viridis. MPs and PAEs present in sea anemone tissues appear to reflect seawater plastic contamination conditions in the study area. Given the rapid biodegradation of PAEs, occurrence and concentrations of both these additives and their metabolites could be useful tracers of short-term plastic debris-biota interactions.

Humic substance/metal-oxide multifunctional nanoparticles as advanced antibacterial-antimycotic agents and photocatalysts for the degradation of PLA microplastics under UVA/solar radiation.

As a result of the accumulation of plastic in the environment, microplastics have become part of the food chain, boosting the resistance of fungi and bacteria which can frequently encounter human beings. Employing photocatalytic degradation is a possible route towards the removal of chemical and biological pollutants, such as plastics and microplastic wastes as well as microorganisms. Using biowaste materials to design hybrid nanoparticles with enhanced photocatalytic and antimicrobial features would uphold the principles of the circular bioeconomy. Here, two unexpensive semiconductors-namely titanium dioxide (TiO2) and zinc oxide (ZnO) - were synthetized through solvothermal synthesis and combined with humic substances deriving from agrifood biomass. The preparation led to hybrid nanoparticles exhibiting enhanced ROS-generating properties for simultaneous applications as antimicrobial agents against different bacterial and fungal strains and as photoactive catalysts to degrade polylactic acid (PLA) microplastics under UVA and solar irradiation. In comparison to bare nanoparticles, hybrid nanoparticles demonstrated higher antibacterial and antimycotic capabilities toward various pathogenic microorganisms as well as advanced photocatalytic activity in the degradation of PLA with a carbonyl index reduction in the range of 15-23%, thus confirming a noteworthy ability in microplastics photodegradation under UVA and solar irradiation.

Characterization of polyethylene terephthalate (PET) and polyamide (PA) true-to-life nanoplastics and their biological interactions.

Plastic and microplastics, including polyethylene (PE), polypropylene (PP), and polystyrene (PS), are major contributors to environmental pollution. However, there is a growing recognition of the need to investigate a wider range of plastic polymers to fully understand the extent and impacts of plastic pollution. This study focuses on the comprehensive characterization of true-to-life nanoplastics (T2LNPs) derived from polyethylene terephthalate (PET) and polyamide (PA) to enhance our understanding of environmental nanoplastics pollution. T2LNPs were produced through cryogenic mechanical fragmentation of everyday items made from these polymers. A solid methodological framework incorporating various characterization techniques was established. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and thermogravimetric analysis (TGA) were employed to study the chemical composition and confirm the absence of chemical modifications possibly occurring during fragmentation. Atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to analyze the morphology of the T2LNPs. Additionally, AFM image analysis compared to dynamic light scattering (DLS) measurements provided insights into the size distribution and the stability of the T2LNP suspensions. The results revealed the heterogeneity of T2LNPs derived from PET and PA, emphasizing the importance of studying different plastic compositions to comprehensively understand nanoplastics pollution. Lastly, the distinctive characteristics and morphology of T2LNPs were translated into the realm of biological interactions, offering initial insights into the influence of these disparities on the formation of the protein corona on the surface of T2LNPs. By proposing T2LNPs as test materials and establishing a comprehensive characterization approach, this study aims to bridge the knowledge gap regarding the behavior and toxicity of nanoplastics. Furthermore, it highlights the need for a reliable and transferable analytical package for nanoplastic characterization to facilitate future studies on the environmental impact of nanoplastics.

Impact of Fibrous Microplastic Pollution on Commercial Seafood and Consumer Health: A Review.

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.

Effectiveness of Mesoporous Silica Nanoparticles Functionalized with Benzoyl Chloride in pH-Responsive Anticorrosion Polymer Coatings.

Smart polymer coatings embedding stimuli-responsive corrosion inhibitor nanocarriers are commonly exploited, in the literature, for the development of high-performance active coatings. In this work, high-surface-area amino-functionalized mesoporous silica nanoparticles (MSN-NH2) were developed with a one-step synthesis process and then functionalized with benzoyl chloride (MSN-BC) through a reaction with amino groups. MSN-BC are able to release benzoic acid (BA) in acid and alkaline conditions as a result of the hydrolysis of the pH-sensitive amide bond. MSN-BC were embedded in polymer coatings to exploit the pH-dependent release of corrosion-inhibiting BA. After an in-depth characterization of the developed functional nanoparticles and of their pH-dependent release kinetics of BA, MSN-BC were embedded in an acrylic matrix, realizing coatings for the corrosion protection of aluminum AA2024 alloys. Results demonstrate the effectiveness of the nanoparticles' porous structure for a high loading of the anticorrosive active agent BA and the long-lasting efficiency of the coating for the corrosion protection of aluminum alloys, as validated by morphological and electrochemical impedance spectroscopy (EIS) measurements. EIS experiments were carried out with up to 21 days of exposure to a corrosive environment, revealing the potentialities of the acrylic coatings embedding MSN-BC for the protection of aluminum alloys.

Effects of biodegradable-based microplastics in Paracentrotus lividus Lmk embryos: Morphological and gene expression analysis.

Plastic pollution is a remarkable environmental issue. In fact, plastic is widespread in the lifetime and serious environmental problems are caused by the improper management of plastic end of life, being plastic litter detected in any environment. Efforts are put to implement the development of sustainable and circular materials. In this scenario, biodegradable polymers, BPs, are promising materials if correctly applied and managed at the end of life to minimize environmental problems. However, a lack of data on BPs fate and toxicity on marine organisms, limits their applicability. In this research, the impact of microplastics obtained from BPs, BMPs, were analyzed on Paracentrotus lividus. Microplastics were produced from five biodegradable polyesters at laboratory scale by milling the pristine polymers, under cryogenic conditions. Morphological analysis of P. lividus embryos exposed to polycaprolactone (PCL), polyhydroxy butyrate (PHB) and polylactic acid (PLA) showed their delay and malformations, which at molecular level are due to variation in expression levels of eighty-seven genes involved in various cellular processes, such as skeletogenesis, differentiation and development, stress, and detoxification response. Exposure to poly(butylene succinate) (PBS) and poly(butylene succinate-co-adipate) (PBSA) microplastics showed no detectable effects on P. lividus embryos. These findings contribute with important data on the effect of BPs on the physiology of marine invertebrates.

Biodegradation of Plastics Induced by Marine Organisms: Future Perspectives for Bioremediation Approaches.

Plastic pollution is a distinctive element of the globalized world. In fact, since the 1970s the expansion and use of plastics, particularly in the consumer and commercial sectors, has given this material a permanent place in our lives. The increasing use of plastic products and the wrong management of end-of-life plastic products have contributed to increasing environmental pollution, with negative impacts on our ecosystems and the ecological functions of natural habitats. Nowadays, plastic pollution is pervasive in all environmental compartments. As aquatic environments are the dumping points for poorly managed plastics, biofouling and biodegradation have been proposed as promising approaches for plastic bioremediation. Known for the high stability of plastics in the marine environment, this represents a very important issue to preserve marine biodiversity. In this review, we have summarized the main cases reported in the literature on the degradation of plastics by bacteria, fungi, and microalgae and the degradation mechanisms involved, to highlight the potential of bioremediation approaches to reduce macro and microplastic pollution.

Research and characterization of fibrous microplastics and natural microfibers in pelagic and benthic fish species of commercial interest.

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.

Poly(lactic acid)/Plasticizer/Nano-Silica Ternary Systems: Properties Evolution and Effects on Degradation Rate.

Plasticized nanocomposites based on poly(lactic acid) have been prepared by melt mixing following a two-step approach, adding two different oligomeric esters of lactic acid (OLAs) as plasticizers and fumed silica nanoparticles. The nanocomposites maintained a remarkable elongation at break in the presence of the nanoparticles, with no strong effects on modulus and strength. Measuring thermo-mechanical properties as a function of aging time revealed a progressive deterioration of properties, with the buildup of phase separation, related to the nature of the plasticizer. Materials containing hydroxyl-terminated OLA showed a higher stability of properties upon aging. On the contrary, a synergistic effect of the acid-terminated plasticizer and silica nanoparticles was pointed out, inducing an accelerated hydrolytic degradation of PLA: materials at high silica content exhibited a marked brittleness and a dramatic decrease of molecular weight after 16 weeks of aging.

A versatile approach to evaluate the occurrence of microfibers in mussels Mytilus galloprovincialis.

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 approach, able to discriminate among natural and synthetic microfibers according to the evaluation of specific morphological features, is proposed in farmed mussels (Mytilus galloprovincialis). The approach was useful to determine that microfibers were present in 74% of mussel samples, with a mean number of 14.57 microfibers/individual, corresponding to 3.13 microfibers/g w.w. A negative correlation between the size of analysed mussels and the amount of microfibers/g w.w. was detected, showing that smaller specimens contained more microfibers than the larger ones. This work paves the way to further studies aimed to adequately assess the risk that microfibers may pose to marine biota, also considering the commercial value as seafood items of many species of the Mytilus genus and the potential implication for human exposure.

Polymer aging affects the bioavailability of microplastics-associated contaminants in sea urchin embryos.

Microplastics (MPs) in the marine environment undergo complex weathering factors that can affect their ability to interact with different coexisting environmental contaminants (termed here co-contaminants). In this study, the influence of artificially aging using UV on the sorption of a complex mixture of co-contaminants onto MPs was investigated in order to provide meaningful hypotheses on their individual and combined toxicities on sea urchin embryos. A mixture of artificially aged MPs (PS particles and PA microfibers) combined with 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), or Cd or Cu, both alone and in a mix, were used to expose embryos of Paracentrotus lividus. The effects of polymer aging on co-contaminants bioavailability were assessed by measuring changes in the transcriptional profile of genes involved in oxidative-stress response and skeletogenic and endo-mesodermal specification. Changes in the sorption ability of MPs to co-contaminants in the aqueous phase highlighted that aging did not affect the sorption of BDE-47 and Cd on MPs, although a certain influence on Cu sorption was found. Despite no morphological effects in embryos at the gastrula stage after MPs/contaminants combinatorial exposure emerged, the greatest influence of the aging process was mainly found for combined exposures which included BDE-47. Finally, the exposure to multiple contaminants generated transcriptional profiles poorly related to those activated by single contaminant, at times suggesting a mixture-dependent different aging influence. These results open new scenarios on the controversial role of vector of co-contaminants for MPs, especially when complex and different types of mixtures were considered.

Sustainable Cellulose-Aluminum-Plastic Composites from Beverage Cartons Scraps and Recycled Polyethylene.

The sustainable management of multilayer paper/plastic waste is a technological challenge due to its composite nature. In this paper, a mechanical recycling approach for multilayer cartons (MC) is reported, illustrating the realization of thermoplastic composites based on recycled polyethylene and an amount of milled MC ranging from 20 to 90 wt%. The effect of composition of the composites on the morphology and on thermal, mechanical, and water absorption behavior was investigated and rationalized, demonstrating that above 80 wt% of MC, the fibrous nature of the filler dominates the overall properties of the materials. A maleated polyethylene was also used as a coupling agent and its effectiveness in improving mechanical parameters of composites up to 60 wt% of MC was highlighted.

Photo-Responsivity Improvement of Photo-Mobile Polymers Actuators Based on a Novel LCs/Azobenzene Copolymer and ZnO Nanoparticles Network.

The efficiency of photomobile polymers (PMP) in the conversion of light into mechanical work plays a fundamental role in achieving cutting-edge innovation in the development of novel applications ranging from energy harvesting to sensor approaches. Because of their photochromic properties, azobenzene monomers have been shown to be an efficient material for the preparation of PMPs with appropriate photoresponsivity. Upon integration of the azobenzene molecules as moieties into a polymer, they act as an engine, allowing fast movements of up to 50 Hz. In this work we show a promising approach for integrating ZnO nanoparticles into a liquid crystalline polymer network. The addition of such nanoparticles allows the trapping of incoming light, which acts as diffusive points in the polymer matrix. We characterized the achieved nanocomposite material in terms of thermomechanical and optical properties and finally demonstrated that the doped PMP was better performing that the undoped PMP film.

Washing load influences the microplastic release from polyester fabrics by affecting wettability and mechanical stress.

Microplastics released from textiles during the washing process represent the most prevalent type of microparticles found in different environmental compartments and ecosystems around the world. Release of microfibres during the washing process of synthetic textiles is due to the mechanical and chemical stresses that clothes undergo in washing machines. Several washing process parameters, conditions, formulations of laundering additives have been correlated to microfibre release and some of them have been identified to affect microfibre release during washing process, while no correlation has been evaluated between microfibre release and washing load. In the present study, microfibre release was evaluated as function of the washing load in a real washing process, indicating a progressive decrease of microfibre release with increasing washing load. The quantity of released microfibres increased by around 5 times by decreasing the washing load due to a synergistic effect between water-volume to fabric ratio and mechanical stress during washing. Moreover, the higher mechanical stress to which the fabric is subjected in the case of a low washing load, hinders the discrimination of the effect on the release of other washing parameters like the type of detergent and laundry additives used.

Innovative Silver-Based Capping System for Mesoporous Silica Nanocarriers Able to Exploit a Twofold Anticorrosive Mechanism in Composite Polymer Coatings: Tailoring Benzotriazole Release and Capturing Chloride Ions.

In this work, engineered stimuli-responsive mesoporous silica nanoparticles (MSNs) were developed and exploited in polymer coatings as multifunctional carriers of a typical corrosion inhibitor, benzotriazole (BTA). In detail, a new capping system based on a BTA-silver coordination complex, able to dissolve in acid and alkaline conditions and to simultaneously tailor the BTA release and the capture of chloride ions, was properly designed and realized. Acrylic coatings embedding the engineered MSNs were deposited onto iron rebar samples and tested for their protective capability in acid and alkaline environments. Results highlighted the high potential of the proposed system for the protection of metals, due to the synergistic effect of the mesoporous structure and the capping system, which guaranteed both the sequestration of chloride ions and the on-demand release of the effective amount of anticorrosive agents able to ensure the enhanced protection of the substrate.

Comparison of biodegradable polyesters degradation behavior in sand.

Sandy beaches represent environmental compartments particularly vulnerable to litter pollution, and they reflect the magnitude of pollution of adjacent compartments: water and coastal areas. The substitution of conventional polymers by biodegradable materials is generally considered as an alternative for reducing environmental accumulation of plastic debris. The present study is aimed to investigate the degradation of poly(lactic acid), poly(ε-caprolactone), poly(butylenesuccinate adipate) and poly(3-hydroxybutyrate) buried in sand for 267 days, simulating them as beach litter. The analysed polyesters showed different degradation mechanisms and kinetics. PLA is mainly subjected to weathering by physical aging; after an initial faster degradation of the amorphous phase, PCL showed a decrease of its degradation rate; similarly to PCL, the degradation of PBSA started from the amorphous phase; PHB is clearly subjected to biological degradation. The degradation trend of the investigated materials in sand decreased in the order PHB > PBSA > PCL > PLA. PLA, PCL and PBSA did not undergo complete degradation in sand during the testing time.