Genotoxicity and metabolic changes induced via ingestion of virgin and UV-aged polyethylene microplastics by the freshwater fish Perca fluviatilis.

The present study aims to compare and assess the toxicity induced by aged (irradiated with ultraviolet radiation for 120 days) polyethylene microplastics (PE-MPs) in comparison to virgin (non-irradiated) ones, after feeding the freshwater fish Perca fluviatilis. To this end, MPs mediated genotoxicity was assessed by the investigation of micronucleus nuclear abnormalities frequency in fish blood, and the degree of DNA damage in the liver and muscle tissues, while metabolic alterations were also recorded in both tissues. Results showed that both virgin and aged PE-MPs induced signaling pathways leading to DNA damage and nuclear abnormalities, as well as metabolites changes in all tissues studied. Metabolic changes revealed that the metabolism of nucleic acids, energy, amino acids, and neurotransmitters was more disrupted in the liver and by aged PE-MPs compared to muscles. Fish fed with aged PE-MPs exhibited greater DNA damage, while blood cells of fish fed with virgin PE-MPs seemed to be more vulnerable to nuclear abnormalities in relation to those fed with aged PE-MPs. Moreover, aged PE-MPs induced more acute overall effects on the metabolic profiles of fish tissues, and initiated stronger stress responses, inflammation, and cellular damages in fish tissues in relation to virgin ones. Characterization of both virgin and aged MPs revealed that the latter exhibited lower crystallinity and melting point, more irregular shapes and higher moiety of oxygen and carbonyl groups, which could be attributed for their observed higher toxicity. The research outcomes provide significant insights for advancing toxicological investigations in this field.

Unravelling psychoactive substances and their metabolites and transformation products: High-Resolution Mass Spectrometry approaches for comprehensive target and suspect screening in wastewater.

Untangling the consumption rates of psychiatric drugs and their metabolites/ transformation products-(TPs) through wastewater gains attention lately. However, the potential environmental impact caused by their release remains ambiguous. As it follows, the monitoring of this class of pharmaceuticals as well as the evaluation of their potential toxicity is a matter of high concern. In the light of the above, here, wastewater samples, were collected in a 1-year and a half sampling campaign (2020-2021) and were further subjected to solid phase extraction. A Q Exactive Focus Orbitrap mass analyzer was employed for the analysis of the samples. For the data curation, except of the monitoring of targets, a comprehensive suspect screening workflow was developed and slightly optimized based on a lab made HRMS database for the investigation of legally or illegally prescribed psychiatric drugs and their relevant metabolites/TPs in influents and effluents. Carbamazepine and amisulpride were quantified at the highest mean concentrations 243 and 225 ng/L respectively, in influents. In effluents, the highest mean concentrations were calculated for carbamazepine (180 ng/L) and venlafaxine (117 ng/L). The implementation of suspect screening approach enhanced the comprehensiveness of analysis by detecting 29 compounds not included in the target list. O-Desmethylvenlafaxine was the predominant metabolite in influents presenting a mean concentration equal to 87 ng/L while the same pattern was also noticed in effluents where the mean concentration was up to 91 ng/L. From the group of suspect compounds for which no analytical standards were available, the predominant compounds with detection frequency 100 % were norephedrine and codeine in influents while in effluents, oxazepam was detected in 81 % of the analyzed samples. Finally, in silico and mathematical tools were employed for the assessment of the risk posed to environmental systems. Most of the detected compounds present high risk in all trophic levels.

Fabrication of Poly(ethylene furanoate)/Silver and Titanium Dioxide Nanocomposites with Improved Thermal and Antimicrobial Properties.

Poly(ethylene furanoate) (PEF)-based nanocomposites were fabricated with silver (Ag) and titanium dioxide (TiO2) nanoparticles by the in-situ polymerization method. The importance of this research work is to extend the usage of PEF-based nanocomposites with improved material properties. The PEF-Ag and PEF-TiO2 nanocomposites showed a significant improvement in color concentration, as determined by the color colorimeter. Scanning electron microscopy (SEM) photographs revealed the appearance of small aggregates on the surface of nanocomposites. According to crystallinity investigations, neat PEF and nanocomposites exhibit crystalline fraction between 0-6%, whereas annealed samples showed a degree of crystallinity value above 25%. Combining the structural and molecular dynamics observations from broadband dielectric spectroscopy (BDS) measurements found strong interactions between polymer chains and nanoparticles. Contact angle results exhibited a decrease in the wetting angle of nanocomposites compared to neat PEF. Finally, antimicrobial studies have been conducted, reporting a significant rise in inhibition of over 15% for both nanocomposite films against gram-positive and gram-negative bacteria. From the overall results, the synthesized PEF-based nanocomposites with enhanced thermal and antimicrobial properties may be optimized and utilized for the secondary packaging (unintended food-contact) materials.

New insights into the size-independent bioactive potential of pristine and UV-B aged polyethylene microplastics.

The present study investigates the morphological, physicochemical, and structural changes occurred by the UV-B aging process of low-density polyethylene microplastics (LDPE MPs), as well as the bioactive potential of both pristine and UVaged MPs towards healthy peripheral blood lymphocytes. Specifically, LDPE MPs (100-180 µm) prepared by mechanical milling of LDPE pellets, were UV-B irradiated for 120 days (wavelength 280 nm; temperature 25 °C; relative humidity 50 %) and further examined for alterations in their particle size and surface, their functional groups, thermal stability, and crystallinity (by means of SEM, FTIR spectroscopy, XRD patterns, and TGA measurements, respectively). In parallel, isolated human peripheral blood lymphocytes were treated with different concentrations (25-500 µg mL-1) of either pristine or aged MPs (UVfree and UV120d LDPE MPs) for assessing the cytogenotoxic (by means of trypan blue exclusion test and the cytokinesis-block micronucleus assay using cytochalasin-B) and oxidative effects (using the DCFH-DA staining) in both cases. According to the results, UVfree and UV120d-LDPE MPs, with a size ranging from 100 to 180 µm, can differentially promote cytogenotoxic and oxidative alterations in human lymphocytes. In fact, UVfree LDPE MPs not being able to be internalized by cells due to their size, could indirectly promote the onset of mild oxidative and cytogenotoxic damage in human peripheral lymphocytes, via a dose-dependent but size-independent manner. The latter is more profound in case of the irregular-shaped UV120d-LDPE MPs, bearing improved dispersibility and sharp edges (by means of cracks and holes), as well as oxygen-containing and carbonyl groups. To our knowledge, the present findings provide new data regarding the bioactive behavior of pristine and UV-B aged LDPE MPs, at least in the in vitro biological model tested, thus giving new evidence for their size-independent and/or indirect mode of action.

Exploring patterns of antibiotics during and after COVID-19 pandemic in wastewaters of northern Greece: Potential adverse effects on aquatic environment.

Antibiotics, recognized as Emerging Contaminants (ECs), have raised concerns due to their pervasive presence in wastewater treatment plants (WWTPs) and subsequent release into aquatic environments, posing potential ecological risks and contributing to the development of antibiotic-resistant genes. The COVID-19 pandemic prompted an unprecedented surge in antibiotic consumption, necessitating a comprehensive assessment of its impact on antibiotic levels in wastewater. In this light, a four-year monitoring study (2020-2023) was conducted in a WWTP located in the Northern Greece (Thessaloniki), employing High-Resolution Mass Spectrometry (HRMS) technology to monitor twenty antibiotics, during distinct phases pre-, during, and post-COVID-19. Our findings revealed that macrolides and fluoroquinolones were among the most often detected categories during the sampling period. Among the compounds detected, azithromycin and clarithromycin showed the most significant increases during the pandemic, doubling their average concentrations. This establishes a clear correlation between the rise in their concentrations and the incidence of COVID-19 cases. A general downward trend after 2021 was attributed to the new restrictions posed in Greece during this year, regarding the liberal prescription of antibiotics. Seasonal variation revealed a minute augmentation of antibiotics' use during the months that infections are increased. Additionally, the study highlights the ecological risks associated with elevated antibiotic presence and emphasizes the need for continued monitoring and regulatory measures to mitigate potential ecological repercussions. These findings contribute to our understanding of the complex interplay between antibiotic consumption, environmental presence, and the COVID-19 pandemic's impact on antibiotic pollution in WWTPs.

Synthesis and evaluation of a chitosan nanomaterial as efficient sorbent for determination of fungicide residues in waters and wine by liquid chromatography high resolution mass spectrometry.

In the present study a novel, cost-effective, environmentally friendly, and efficient analytical method was developed to analyze fungicide residues in water and wine. The method relies on the application of a newly developed sorbent nanomaterial named Nano-Cs-NAT, synthesized by modifying chitosan, a naturally occurring, low-cost polysaccharide, through grafting with two acrylic monomers and a cross-linker. Nano-Cs-NAT was introduced as analytical sorbent for Dispersive Micro Solid Phase Extraction (D-µ-SPE) before Liquid Chromatography-Orbitrap High-Resolution Mass Spectrometry (LC-Orbitrap HRMS) analysis of twelve fungicides commonly used in viticulture (among the others, triazoles, strobilurines and N-substituted imidazoles). Characterization of the sorbent was conducted, confirming the successful acrylation of chitosan. A multivariate approach was employed to optimize D-µ-SPE extraction parameters. The material was found to be highly effective in simultaneously purifying and concentrating the target analytes, enhancing overall analytical efficiency and sensitivity. The Nano-Cs-NAT-D-µ-SPE-LC-Orbitrap-HRMS method was thoroughly validated, exhibiting good recoveries (72-104%), reproducibility (average RSD ≤ 6%) and repeatability (average RSD ≤ 7%). It also achieved low limits of detection (LOD) in river water (average LOD of 0.04 µg L-1) and wine (average LOD of 0.72 µg kg-1), highlighting its potential for routine fungicide residue analysis. This developed method addresses environmental and food safety concerns by providing an efficient solution for detecting fungicide residues in waters and wine.

Extracting Structural Information from Physicochemical Property Measurements Using Machine Learning─A New Approach for Structure Elucidation in Non-targeted Analysis.

Non-targeted analysis (NTA) has made critical contributions in the fields of environmental chemistry and environmental health. One critical bottleneck is the lack of available analytical standards for most chemicals in the environment. Our study aims to explore a novel approach that integrates measurements of equilibrium partition ratios between organic solvents and water (KSW) to predictions of molecular structures. These properties can be used as a fingerprint, which with the help of a machine learning algorithm can be converted into a series of functional groups (RDKit fragments), which can be used to search chemical databases. We conducted partitioning experiments using a chemical mixture containing 185 chemicals in 10 different organic solvents and water. Both a liquid chromatography quadrupole time-of-flight mass spectrometer (LC-QTOF MS) and a LC-Orbitrap MS were used to assess the feasibility of the experimental method and the accuracy of the algorithm at predicting the correct functional groups. The two methods showed differences in log KSW with the QTOF method showing a mean absolute error (MAE) of 0.22 and the Orbitrap method 0.33. The differences also culminated into errors in the predictions of RDKit fragments with the MAE for the QTOF method being 0.23 and for the Orbitrap method being 0.31. Our approach presents a new angle in structure elucidation for NTA and showed promise in assisting with compound identification.

Photo-assisted transformation of furosemide: Exploring transformation pathways, structure database and suspect and non-target workflows for comprehensive screening of unknown transformation products in wastewaters and landfill leachates.

In recent years, transformation products-(TPs) of pharmaceuticals in the environment have received considerable attention. In this context, here, a customized overview of transformation of Furosemide-(FRS) in aqueous matrices treated by photo-oxidation is provided as a proof of concept. Hence, the primary goal of the study was to display an integrated strategy by combining the target (parent-molecule) and suspect screening-(SS) approaches (TPs) in order to build an in-house High-Resolution mass spectrometry (HRMS) database able to provide reference information (chromatographic/spectral) for environmental investigations in complex matrices (wastewaters/landfill leachates). Data analysis was performed by optimizing a SS workflow. Additional confirmation for the proposed structural elucidation was provided by correlating retention time to the proposed structure employing three prediction models. This approach was applied for the tentative identification of 35 TPs of FRS, 28 of which are reported herein for the first time. Finally, SS and non-target analysis (NTA) have been successfully applied for retrospective screening of FRS and its TPs in real samples. The findings demonstrated that SS allows the proper identification of TPs of FRS in complex matrices proving its outstanding importance compared to NTA. In total, six TPs were identified by SS with potential ecotoxicological implications for two of them according to in silico risk assessment.

Effect of Monomer Type on the Synthesis and Properties of Poly(Ethylene Furanoate).

This work aimed to produce bio-based poly(ethylene furanoate) (PEF) with a high molecular weight using 2,5-furan dicarboxylic acid (FDCA) or its derivative dimethyl 2,5-furan dicarboxylate (DMFD), targeting food packaging applications. The effect of monomer type, molar ratios, catalyst, polycondensation time, and temperature on synthesized samples' intrinsic viscosities and color intensity was evaluated. It was found that FDCA is more effective than DMFD in producing PEF with higher molecular weight. A sum of complementary techniques was employed to study the structure-properties relationships of the prepared PEF samples, both in amorphous and semicrystalline states. The amorphous samples exhibited an increase in glass transition temperature of 82-87 °C, and annealed samples displayed a decrease in crystallinity with increasing intrinsic viscosity, as analyzed by differential scanning calorimetry and X-ray diffraction. Dielectric spectroscopy showed moderate local and segmental dynamics and high ionic conductivity for the 2,5-FDCA-based samples. The spherulite size and nuclei density of samples improved with increased melt crystallization and viscosity, respectively. The hydrophilicity and oxygen permeability of the samples were reduced with increased rigidity and molecular weight. The nanoindentation test showed that the hardness and elastic modulus of amorphous and annealed samples is higher at low viscosities due to high intermolecular interactions and degree of crystallinity.

Does climbazole instigate a threat in the environment as persistent, mobile and toxic compound? Unveiling the occurrence and potential ecological risks of its phototransformation products in the water cycle.

Persistent, mobile, and toxic chemicals (PMT), such as the antimycotic climbazole-(CBZ), proliferate in water cycle and imperil drinking water quality, sparking off research about their environmental fate. Unlike the parent compound, its transformation products-(TPs) are scarcely investigated, much less as PMTs. To this end, phototransformation of CBZ was investigated. A novel suspect-screening workflow was developed and optimized by cross-comparing the results of the identified photo-TPs against literature data to create an enhanced HRMS-database for environmental investigations of CBZ/TPs in the water cycle. In total, 24 TPs were identified, 14 of which are reported for the first time. Isomerism, dechlorination, hydroxylation, and cleavage of the ether or C-N bond are suggested as the main transformation routes. A screening of CBZ/TPs was conducted in wastewater, leachates, surface, and groundwater, revealing a maximum concentration of 464.8 ng/L in groundwater. In silico and in vitro methods were used for toxicity assessment, indicating toxicity for CBZ and some TPs. Seemingly, CBZ is rightly considered as PMT, and a higher potential to occur in surface or groundwater than non-PM chemicals appears. Likewise, the occurrence of TPs due to PMT properties or emission patterns was evaluated.

Membranes Coated with Graphene-Based Materials: A Review.

Graphene is a popular material with outstanding properties due to its single layer. Graphene and its oxide have been put to the test as nano-sized building components for separation membranes with distinctive structures and adjustable physicochemical attributes. Graphene-based membranes have exhibited excellent water and gas purification abilities, which have garnered the spotlight over the past decade. This work aims to examine the most recent science and engineering cutting-edge advances of graphene-based membranes in regard to design, production and use. Additional effort will be directed towards the breakthroughs in synthesizing graphene and its composites to create various forms of membranes, such as nanoporous layers, laminates and graphene-based compounds. Their efficiency in separating and decontaminating water via different techniques such as cross-linking, layer by layer and coating will also be explored. This review intends to offer comprehensive, up-to-date information that will be useful to scientists of multiple disciplines interested in graphene-based membranes.

Synthesis of Poly(ethylene furanoate) Based Nanocomposites by In Situ Polymerization with Enhanced Antibacterial Properties for Food Packaging Applications.

Poly(ethylene 2,5-furandicarboxylate) (PEF)-based nanocomposites containing Ce-bioglass, ZnO, and ZrO2 nanoparticles were synthesized via in situ polymerization, targeting food packaging applications. The nanocomposites were thoroughly characterized, combining a range of techniques. The successful polymerization was confirmed using attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy, and the molecular weight values were determined indirectly by applying intrinsic viscosity measurements. The nanocomposites' structure was investigated by depth profiling using time-of-flight secondary ion mass spectrometry (ToF-SIMS), while color measurements showed a low-to-moderate increase in the color concentration of all the nanocomposites compared to neat PEF. The thermal properties and crystallinity behavior of the synthesized materials were also examined. The neat PEF and PEF-based nanocomposites show a crystalline fraction of 0-5%, and annealed samples of both PEF and PEF-based nanocomposites exhibit a crystallinity above 20%. Furthermore, scanning electron microscopy (SEM) micrographs revealed that active agent nanoparticles are well dispersed in the PEF matrix. Contact angle measurements showed that incorporating nanoparticles into the PEF matrix significantly reduces the wetting angle due to increased roughness and introduction of the polar -OH groups. Antimicrobial studies indicated a significant increase in inhibition of bacterial strains of about 9-22% for Gram-positive bacterial strains and 5-16% for Gram-negative bacterial strains in PEF nanocomposite films, respectively. Finally, nanoindentation tests showed that the ZnO-based nanocomposite exhibits improved hardness and elastic modulus values compared to neat PEF.

Dose-Dependent Cytotoxicity of Polypropylene Microplastics (PP-MPs) in Two Freshwater Fishes.

The massive accumulation of plastics over the decades in the aquatic environment has led to the dispersion of plastic components in aquatic ecosystems, invading the food webs. Plastics fragmented into microplastics can be bioaccumulated by fishes via different exposure routes, causing several adverse effects. In the present study, the dose-dependent cytotoxicity of 8−10 µm polypropylene microplastics (PP-MPs), at concentrations of 1 mg/g (low dose) and 10 mg/g dry food (high dose), was evaluated in the liver and gill tissues of two fish species, the zebrafish (Danio rerio) and the freshwater perch (Perca fluviatilis). According to our results, the inclusion of PP-MPs in the feed of D. rerio and P. fluviatilis hampered the cellular function of the gills and hepatic cells by lipid peroxidation, DNA damage, protein ubiquitination, apoptosis, autophagy, and changes in metabolite concentration, providing evidence that the toxicity of PP-MPs is dose dependent. With regard to the individual assays tested in the present study, the biggest impact was observed in DNA damage, which exhibited a maximum increase of 18.34-fold in the liver of D. rerio. The sensitivity of the two fish species studied differed, while no clear tissue specificity in both fish species was observed. The metabolome of both tissues was altered in both treatments, while tryptophan and nicotinic acid exhibited the greatest decrease among all metabolites in all treatments in comparison to the control. The battery of biomarkers used in the present study as well as metabolomic changes could be suggested as early-warning signals for the assessment of the aquatic environment quality against MPs. In addition, our results contribute to the elucidation of the mechanism induced by nanomaterials on tissues of aquatic organisms, since comprehending the magnitude of their impact on aquatic ecosystems is of great importance.

Root-associated bacteria modulate the specialised metabolome of Lithospermum officinale L.

Bacteria influence plant growth and development and therefore are attractive resources for applications in agriculture. However, little is known about the impact of these microorganisms on secondary metabolite (SM) production by medicinal plants. Here we assessed, for the first time, the effects of bacteria on the modulation of SM production in the medicinal plant Lithospermum officinale (Boraginaceae family) with a focus on the naphthoquinones alkannin/shikonin and their derivatives (A/Sd). The study was conducted in an in vitro cultivation system developed for that purpose, as well as in a greenhouse. Targeted and non-targeted metabolomics were performed, and expression of the gene PGT encoding for a key enzyme in the A/S biosynthesis pathway was evaluated with qPCR. Three strains, Chitinophaga sp. R-73072, Xanthomonas sp. R-73098 and Pseudomonas sp. R-71838 induced a significant increase of A/Sd in L. officinale in both systems, demonstrating the strength of our approach for screening A/Sd-inducing bacteria. The bacterial treatments altered other plant metabolites derived from the shikimate pathway as well. Our results demonstrate that bacteria influence the biosynthesis of A/Sd and interact with different metabolic pathways. This work highlights the potential of bacteria to increase the production of SM in medicinal plants and reveals new patterns in the metabolome regulation of L. officinale.

Cosmetic wastewater treatment technologies: a review.

Over the past three decades, environmental concerns about the water pollution have been raised on societal and industrial levels. The presence of pollutants stemming from cosmetic products has been documented in wastewater streams outflowing from industrial as well as wastewater treatment plants. To this end, a series of consistent measures should be taken to prevent emerging contaminants of water resources. This need has driven the development of technologies, in an attempt to mitigate their impact on the environment. This work offers a thorough review of existing knowledge on cosmetic wastewater treatment approaches, including, coagulation, dissolved air flotation, adsorption, activated sludge, biodegradation, constructed wetlands, and advanced oxidation processes. Various studies have already documented the appearance of cosmetics in samples retrieved from wastewater treatment plants (WWTPs), which have definitely promoted our comprehension of the path of cosmetics within the treatment cycle; however, there are still multiple blanks to our knowledge. All treatments have, without exception, their own limitations, not only cost-wise, but also in terms of being feasible, effective, practical, reliable, and environmentally friendly.

Screening of pesticides and emerging contaminants in eighteen Greek lakes by using target and non-target HRMS approaches: Occurrence and ecological risk assessment.

Lakes, albeit ecosystems of vital importance, are insufficiently investigated with respect to the degradation of water quality due to the organic micropollutants load. As regards Greece, screening of lake waters is scarce and concerns a limited number of contaminants. However, understanding the occurrence of contaminants of emerging concern (CECs) and other micropollutants in lakes is essential to appraise their potential ecotoxicological effects. The aim of this study was to deploy a multiresidue screening approach based on liquid chromatography-high-resolution mass spectrometry (HRMS) to get a first snapshot for >470 target CECs, including pesticides, pharmaceuticals, personal care products (PPCPs), per- and polyfluoroalkyl substances (PFASs), as well as organophosphate flame retardants (OPFRs) in eighteen Greek lakes in Central, Northern and West Northern Greece. The omnipresent compounds were DEET (N,N-diethyl-meta-toluamide), caffeine and TCPP (tris (1-chloro-2-propyl) phosphate). Maximum concentrations varied among the different classes. DEET was detected at a maximum average concentration of >1000 ng/L in Lake Orestiada, while its mean concentration was estimated at 233 ng/L. The maximum total concentrations for pesticides, PPCPs, PFASs, and OPFRs were 5807, 2669, 33.1, and 1214 ng/L, respectively, indicating that Greek lakes are still threatened by the intense agricultural activity. Besides, HRMS enabled a non-target screening by exploiting the rich content of the full-scan raw data, allowing the 'discovery' of tentative candidates, such as surfactants, pharmaceuticals, and preservatives among others, without reference standards. The potential ecotoxicity was assessed by both the risk quotient method and ECOSAR (Ecological Structure Activity Relationships) revealing low risk for most of the compounds.

HRMS screening of organophosphate flame retardants and poly-/perfluorinated substances in dust from cars and trucks: Occurrence and human exposure implications.

Time spent within vehicles' cabin has been largely increased during the last years. As a result, the assessment of indoor dust quality is meaningful since dust can be a source of numerous emerging contaminants associated with adverse effects in human health. To this end, fourteen cars and ten trucks from the city of Thessaloniki, Northern Greece were selected to assess the quality of vehicles' microenvironments. An HRMS-based strategy was deployed for the target and non-target analysis of the collected samples. The target approach aimed at the accurate mass screening of nine organophosphate flame retardants (OPFRs) and nine per-/polyfluorinated compounds (PFAS), revealing mean concentrations for the OPFRs varied from

Do poly(lactic acid) microplastics instigate a threat? A perception for their dynamic towards environmental pollution and toxicity.

Fears concerning microplastics (MPs) environmental fate and persistence are progressively expanding on a global basis, with the emphasis given to manufacturing bioplastics for substituting petro-derived plastics extensively growing. Among them, poly(lactic acid) (PLA) holds a pioneering role towards the replacement of conventional polymeric materials, owing to its multifunctional properties, enclosing superior mechanical properties, low cost, renewability, great biocompatibility, transparency, and thermoplasticity launching many fields of application. Due to the wide applicability of PLA in several sectors of everyday life, its waste to be released into the environment is expected to follow a growing tendency during the upcoming years. Even though PLA is a biodegradable polyester, it actually degrades under specific composting environments, including a rich oxygen environment with high temperatures (58-80 °C), high humidity (>60% moisture) as well as the presence of micro-organisms (thermophilic bacteria). Additionally, in various studies it has been implied that PLA displays slower degradation performance when found in blends with other conventional polymers, underlining the unspecified effects on PLA degradation profile, keeping thus the information about PLA degradation from a blur standpoint. Therefore, a deepened understanding of the fate and dynamic effects of PLA MPs is of primary importance. Nevertheless, the current examination of the effects of PLA MPs in terms of sorption capacities and toxicity is so far limited and broadly unexplored since the current scientific emphasis has been merely centered on the conventional MPs' behavior. In this light, the present review provides an inclusive overview of the ongoing research of poly(lactic acid) in the framework of microplastics' pollution, while the future trends and missing points in this context are highlighted.

Differentiation in the expression of toxic effects of polyethylene-microplastics on two freshwater fish species: Size matters.

The built up of microplastic (MPs) remains is shaping a new aquatic habitat and imposes the necessity for research of the effects that these relatively new pollutants exert on organisms, environment, and human health. The purpose of the present study was to verify if there is a particle-size dependence of fish response to MPs. Thus, we exposed two freshwater fish species, the zebrafish (Danio rerio) and perch (Perca fluviatilis) for 21 days to polyethylene microplastics (PE-MPs) sized 10-45 µm and 106-125 µm. Thereafter, in the liver and gills tissues, biochemical and molecular parameters and the metabolic profile were examined. Ex-vivo characterization by ATR-FTIR spectroscopy exhibited increased concentration of 10-45 µm PE-MPs in the liver of the two fish species while 106-125 µm PE-MPs mostly concentrated in fish gills. The penetration of PE-MPs to fish and the induced oxidative stress triggered changes in lipid peroxidation, DNA damage and ubiquitination and furthermore stimulated signal transduction pathways leading to autophagy and apoptosis. The smaller PE-MPs were more potent in inducing alterations to all the latter parameters measured than the larger ones. Tissue response in both fish seems to depend on the parameter measured and does not seem to follow a specific pattern. Our results showed that there is no clear sensitivity of one fish species versus the other, against both sizes of PE-MPs they were exposed. In perch the metabolic changes in gills were distinct to the ones observed in liver, following a size dependent pattern, indicating that stress conditions are generated through different mechanisms. All the parameters employed can be suggested further as biomarkers in biomonitoring studies against PE-MPs.

Toxicity and Functional Tissue Responses of Two Freshwater Fish after Exposure to Polystyrene Microplastics.

Microplastics (MPs)' ingestion has been demonstrated in several aquatic organisms. This process may facilitate the hydrophobic waterborne pollutants or chemical additives transfer to biota. In the present study the suitability of a battery of biomarkers on oxidative stress, physiology, tissue function and metabolic profile was investigated for the early detection of adverse effects of 21-day exposure to polystyrene microplastics (PS-MPs, sized 5-12 µm) in the liver and gills of zebrafish Danio rerio and perch, Perca fluviatilis, both of which are freshwater fish species. An optical volume map representation of the zebrafish gill by Raman spectroscopy depicted 5 µm diameter PS-MP dispersed in the gill tissue. Concentrations of PS-MPs close to the EC50 of each fish affected fish physiology in all tissues studied. Increased levels of biomarkers of oxidative damage in exposed fish in relation to controls were observed, as well as activation of apoptosis and autophagy processes. Malondialdehyde (MDA), protein carbonyls and DNA damage responses differed with regard to the sensitivity of each tissue of each fish. In the toxicity cascade gills seemed to be more liable to respond to PS-MPs than liver for the majority of the parameters measured. DNA damage was the most susceptible biomarker exhibiting greater response in the liver of both species. The interaction between MPs and cellular components provoked metabolic alterations in the tissues studied, affecting mainly amino acids, nitrogen and energy metabolism. Toxicity was species and tissue specific, with specific biomarkers responding differently in gills and in liver. The fish species that seemed to be more susceptible to MPs at the conditions studied, was P. fluviatilis compared to D. rerio. The current findings add to a holistic approach for the identification of small sized PS-MPs' biological effects in fish, thus aiming to provide evidence regarding PS-MPs' environmental impact on wild fish populations and food safety and adequacy.