Microplastics in the stomach content of the commercial fish species Scomber colias in the Gulf of Cadiz, SW Europe.

Concerning microplastics (MPs) contamination is increasing due their negative impacts on marine food webs and their potential toxicity to wildlife and humans. In this study, we analyze the presence of MPs in the stomachs of the commercial fish species Scomber colias (Atlantic chub mackerel) in the Gulf of Cadiz (GoC). Out of the 104 analyzed stomachs, 90.4 % contained some type of MPs, with an average of 5.4 MPs per individual. Of the 1152 MPs analyzed, 91.1 % were fibers, and 8.9 % fragments type. Fourier Transformation Infrared Spectrometry analysis was performed on 152 items, revealing that 73.6 % were MPs. The most common synthetic polymers found were polyamide (64 %), polypropylene (15 %), polystyrene (12 %), polyvinyl chloride (5 %), and polyethylene (4 %). The consistent ingestion of synthetic polymers by the individuals of Atlantic chub mackerel across different zones might suggest an even distribution of MP contamination throughout the GoC.

Contamination from microplastics and other anthropogenic particles in the digestive tracts of the commercial species Engraulis encrasicolus and Sardina pilchardus.

Fragments of microplastics (<5 mm) found in commercial species of fish, crustaceans, and bivalves, are an issue of global concern. The bioaccumulation of microplastics and other anthropogenic particles in different levels of the food web may provoke unwanted impacts on marine ecosystems and cause pernicious effects on human health. Here, we study the presence of anthropogenic particles and the fraction of microplastics in the target organs of two representative commercial fish species in Spain; the European anchovy (Engraulis encrasicolus) and the European pilchard (Sardina pilchardus). The individuals were sampled along the continental shelf of the Gulf of Cádiz, from the Bay of Cádiz to Cape Santa Maria. The isolation of the microplastics (MPs) was carried out with a complete alkaline-oxidant organic digestion (KOH-H2O2) of the digestive tract, including both the contents ingested and the muscle tissues. Anthropogenic particles were found in all individuals of both species with an average of 8.94 ± 5.11 items·ind-1. Fibres made up 93 % of the items while fragments and films were represented by the remaining 7 %. The average size of the anthropogenic particles was 0.89 ± 0.82 mm. In addition to the fragment and film particles identified as microplastics, 29 % of the fibres were estimated to be microplastics by Fourier-transform infrared spectroscopy (FTIR) analysis. The main polymer found in both species was nylon. No significant correlation was found between the abundance and size of anthropogenic particles ingested and individual size or other body variables. The analysis of similarities (ANOSIM) and the distanced-based multiple linear regression model showed a high homogeneity in anthropogenic particle contamination in both species throughout the study area along the continental shelf of the Gulf of Cádiz.

CO Methanation over NiO-CeO2 Mixed-Oxide Catalysts Prepared by a Modified Co-Precipitation Method: Effect of the Preparation pH on the Catalytic Performance.

In this study, a series of NiO-CeO2 mixed-oxide catalysts have been prepared by a modified co-precipitation method similar to the one used for the synthesis of hydrotalcites. The syntheses were carried out at different pH values (8, 9 and 10), in order to determine the influence of this synthetic variable on the properties of the obtained materials. These materials were characterized by using different techniques, such as TGA, XRD, ICP, N2 adsorption-desorption isotherms, H2 temperature-programmed reduction (H2-TPR), and electron microscopy, including high-angle annular dark-field transmission electron microscopy (HAADF-TEM) and EDS. The characterization results revealed the influence of the preparation method, in general, and of the pH value, in particular, on the textural properties of the oxides, as well as on the dispersion of the Ni species. The catalyst prepared at a higher pH value (pH = 10) was the one that exhibited better behavior in the CO methanation reaction (almost 100% CO conversion at 235 °C), which is attributed to the achievement, under these synthetic conditions, of a combination of properties (metal dispersion, specific surface area, porosity) more suitable for the reaction.

Products released from surgical face masks can provoke cytotoxicity in the marine diatom Phaeodactylum tricornutum.

Surgical face masks are more present than ever as personal protective equipment due to the COVID-19 pandemic. In this work, we show that the contents of regular surgical masks: i) polypropylene microfibres and ii) some added metals such as: Al, Fe, Cu, Mn, Zn and Ba, may be toxic to some marine life. This work has got two objectives: i) to study the release rate of the products from face masks in marine water and ii) to assess the toxicity in Phaeodactylum tricornutum of these by-products. To achieve these two objectives, we performed release kinetic experiments by adding masks in different stages of fragmentation to marine water (i.e. whole face masks and fragments of them 1.52 ± 0.86 mm). Released microfibres were found after one month in shaking marine water; 0.33 ± 0.24 and 21.13 ± 13.19 fibres·mL-1 were collected from the whole and fragmented face masks, respectively. Significant amounts of dissolved metals such as Mn, Zn and Ni, as well as functional groups only in the water containing the face mask fragments were detected. Water from both treatments was employed to study its toxicity on the marine diatom. Only the water from the face mask fragments showed a significant, dose-dependent, decrease in cell density in P. tricornutum; 53.09 % lower than in the controls. Although the water from the face mask fragments showed greater effects on the microalgae population than the water from the whole face mask, the latter treatment did show significant changes in the photosynthetic apparatus and intrinsic properties of the cells. These results indicate that during fragmentation and degradation face masks a significant chemical print can be observed in the marine environment.

Reactivity of Vanadium Nanoparticles with Oxygen and Tungsten.

A mechanistic study was carried out on the optimal methods of fabrication of products containing higher loads of thermochromic VO2(M1) fabricated by thermal treatments of V nanoparticles in air, that, once achieved, are more stable than other commercial products upon natural aging or reiterated reheating. At the best temperatures for single runs, 55% of VO2 can be attained by the reactions of a limited number of the species initially formed in a process, that, if not stopped, can degrade the product by solid state reactions of oxidations and reductions without O2 consumption. This fact supports the use of two-step treatments at lower temperatures and faster cooling rates that reach 65% of VO2; such reactions should, ideally, take place in the 550-625 °C temperature range. The impregnation of V with a tungstate salt is an ideal and simple doping platform that can decrease the energy of activation of the 2-cycle process, allowing higher yields and enthalpies of transformation (71% of VO2, 26 J/g) than undoped counterparts or trademarks. A good balance is reached for 1% at. of W, with a reduction in Tc of 20 °C not significantly resenting the enthalpy of the reversible metal-to-insulator transition. For higher W amounts, the appearance of tetragonal VO2, and W alloyed V3O7 and V2O5, decrease the fractions of increasingly and effectively doped M1-VO2 achieved till 2% of W, a concentration for which Tc attains the stimulating values of 35 °C on heating and 25 °C on cooling.

Surgical face masks as a source of emergent pollutants in aquatic systems: Analysis of their degradation product effects in Danio rerio through RNA-Seq.

Surgical face masks are the most popularised and effective personal equipment for protecting public health during the COVID-19 pandemic. They are composed of plastic polymer fibres with a large amount of inorganic and organic compounds that can be released into aquatic environments through degradation processes. This source of microplastics and inorganic and organic substances could potentially impact aquatic organisms. In this study, the toxicogenomic effects of face masks at different stages of degradation in water were analysed in zebrafish larvae (Danio rerio) through RNA-Seq. Larvae were exposed for 10 days to three treatments: 1) face mask fragments in an initial stage of degradation (poorly degraded masks -PDM- products) with the corresponding water; 2) face mask fragments in an advanced stage of degradation (highly degraded masks -HDM- products) with the corresponding water; and 3) water derived from HDM (W-HDM). Transcriptome analyses revealed that the three treatments provoked the down-regulation of genes related to reproduction, especially the HDM products, suggesting that degradation products derived from face masks could act as endocrine disruptors. The affected genes are involved in different steps of reproduction, including gametogenesis, sperm-egg recognition and binding or fertilisation. Immune-related genes and metabolic processes were also differentially affected by the treatments.

Coastal gradients of small microplastics and associated pollutants influenced by estuarine sources.

Small microplastics (SMPs) in the gulf of Cadiz was sampled at 5 m depth by pumping it through the ship's pipe system and filtered through a 45 µm mesh size net. Our study reveals that higher densities have been found (130 mg·m-3) compared to other regions worldwide and these densities decreased from the coastline to the outer stations, showing a general coastal gradient influenced by estuarine outflows. SMPs with a size range between 45 and 193 µm were predominant and most of them composed by polyethylene and polypropylene. The metals associated with the MPs were mainly Na (21.1%), K (11.3%), Fe (8.5%), Ca (2.1%), Cr (1.8%), Zr (13.3%) and Hf (0.7%). The high proportion of Zr compared to Fe, which is different from what can be found in the environment, suggests that this metal is intrinsic to the materials used in catalytic processes during plastic production.

Ultrathin Washcoat and Very Low Loading Monolithic Catalyst with Outstanding Activity and Stability in Dry Reforming of Methane.

A Ni/CeO2/ZrO2 catalyst with improved redox properties has been washcoated onto a honeycomb cordierite monolith in the form of a nonconventional alumina-catalyst layer, just a few nanometers thick. In spite of the very low active phase loading, the monolith depicts outstanding performance in dry reforming of methane, both in terms of activity, with values reaching the thermodynamic limit already at 750 °C, even under extreme Weight Hourly Space Velocities (WHSV 115-346 L·g-1·h-1), as well as in terms of stability during prolonged Time on Stream (TOS 24-48 h).

Performance of a Direct Methane Solid Oxide Fuel Cell Using Nickel-Ceria-Yttria Stabilized Zirconia as the Anode.

A nickel-ceria-yttria stabilized zirconia (Ni-CYSZ) cermet material was synthesized and tested as the anode for the direct oxidation of methane in a solid oxide fuel cell (SOFC) with YSZ as the electrolyte and strontium-doped lanthanum manganite (LSM) as the cathode. Initially, the electrochemical behavior was investigated under several load demands in wet (3% H2O) CH4 at 850 °C during 144 h using I-V curves, impedance spectra, and potentiostatic measurements. Long-term tests were subsequently conducted under 180 mA·cm-2 in wet CH4 for 236 h and dry CH4 for 526 h at 850 °C in order to assess the cell stability. Material analysis was carried out by SEM-EDS after operation was complete. Similar cell performance was observed with wet (3% H2O) and dry CH4, and this indicates that the presence of water is not relevant under the applied load demand. Impedance spectra of the cell showed that at least three processes govern the direct electrochemical oxidation of methane on the Ni-CYSZ anode and these are related to charge transfer at high frequency, the adsorption/desorption of charged species at medium frequency and the non-charge transfer processes at low frequency. The cell was operated for more than 900 h in CH4 and 806 h under load demand, with a low degradation rate of ~0.2 mV·h-1 observed during this period. The low degradation in performance was mainly caused by the increase in charge transfer resistance, which can be attributed to carbon deposition on the anode causing a reduction in the number of active centers. Carbon deposits were detected mostly on the surface of Ni particles but not near the anode/electrolyte interface or the cerium surface. Therefore, the incorporation of cerium in the anode structure could improve the cell lifetime by reducing carbon formation.

Catalytic Soot Oxidation Activity of NiO-CeO2 Catalysts Prepared by a Coprecipitation Method: Influence of the Preparation pH on the Catalytic Performance.

A series of NiO-CeO2 mixed oxide catalysts have been synthesized by a modified coprecipitation method at three different pH values (pH = 8, 9, and 10). The NiO-CeO2 mixed oxide samples were characterized by TGA, XRD, inductively coupled plasma atomic emission spectroscopy (ICP-AES), FTIR, Brunauer-Emmett-Teller (BET) surface area, H2 temperature-programmed reduction (H2-TPR), and electron microscopy (high-angle annular dark-field transmission electron microscopy/energy-dispersive X-ray spectroscopy (HAADF-TEM/EDS)). The catalytic activities of the samples for soot oxidation were investigated under loose and tight contact conditions. The catalysts exhibited a high BET surface area with average crystal sizes that varied with the pH values. Electron microscopy results showed the formation of small crystallites (~5 nm) of CeO2 supported on large plate-shaped particles of NiO (~20 nm thick). XRD showed that a proportion of the Ni2+ was incorporated into the ceria network, and it appeared that the amount on Ni2+ that replaced Ce4+ was higher when the synthesis of the mixed oxides was carried out at a lower pH. Among the synthesized catalysts, Ni-Ce-8 (pH = 8) exhibited the best catalytic performance.

Are the primary characteristics of polystyrene nanoplastics responsible for toxicity and ad/absorption in the marine diatom Phaeodactylum tricornutum?

Nowadays, the occurrence of a large volume of plastic litter in oceanic and coastal zones has increased concern about its impacts on marine organisms. The degradation of plastic polymers leads to the formation of smaller fragments at both micro and nano scale (<5 mm and <1 µm respectively). Nanoplastics (NPs), due to their smaller size and high specific surface area can establish colloidal interactions with marine microalgae, therefore potential toxicity can be led. . To assess this hypothesis, the aim of the present study is to examine the behaviour of polystyrene nanoparticles (PS NPs) of different sizes (50 and 100 nm) in marine water and their possible effects at different physiological and cellular levels in the marine diatom Phaeodactylum tricornutum. Different biomarkers and stress responses in P. tricornutum were analysed when organisms were exposed to environmentally relevant PS NPs concentrations between 0.1 and 50 mg L-1. Our results showed significant differences between controls and exposure microalgae, indicating toxicity. After 24 h, an increase in oxidative stress biomarkers, damage to the photosynthetic apparatus, DNA damage and depolarization of mitochondrial and cell membrane from 5 mg L-1 were observed. Further after 72 h the inhibition of population growth and chlorophyll content were observed. Examining effects the effects related to PS NPs size, the smallest (50 nm) induced greater effects at 24 h while bigger PS NPs (100 nm) at72 h. This bigger particles (100 nm) showed more stability (in size distribution and spherical form) in the different culture media assayed, when compared with the rest of particles used. Strong adsorption and/or internalization of PS NPs was confirmed through changes in cell complexity and cell size as well as the fluorescence of 100 nm fluoresbrite PS NPs after washing cell surface.

Synthesis methods influence characteristics, behaviour and toxicity of bare CuO NPs compared to bulk CuO and ionic Cu after in vitro exposure of Ruditapes philippinarum hemocytes.

Copper oxide (CuO) nanoparticles (NPs) are increasingly investigated, developed and produced for a wide range of industrial and consumer products. Notwithstanding their promising novel applications, concern has been raised that their increased use and disposal could consequently increase their release into marine systems and potentially affect species within. To date the understanding of factors and mechanisms of CuO (nano-) toxicity to marine invertebrates is still limited. Hence, we studied the characteristics and behaviour of two commercially available CuO NPs of similar size, but produced employing distinct synthesis methods, under various environmentally and experimentally relevant conditions. In addition, cell viability and DNA damage, as well as gene expression of detoxification, oxidative stress, inflammatory response, DNA damage repair and cell death mediator markers were studied in primary cultures of hemocytes from the marine clam Ruditapes philippinarum and, where applicable, compared to bulk CuO and ionic Cu (as CuSO4) behaviour and effects. We found that the synthesis method can influence particle characteristics and behaviour, as well as the toxicity of CuO NPs to Ruditapes philippinarum hemocytes. Our results further indicate that under the tested conditions aggregating behaviour influences the toxicity of CuO NPs by influencing their rate of extra- and intracellular dissolution. In addition, gene expression analysis identified similar transcriptional de-regulation for all tested copper treatments for the here measured suite of genes. Finally, our work highlights various differences in the aggregation and dissolution kinetics of CuO particles under environmental (marine) and cell culture exposure conditions that need consideration when extrapolating in vitro findings.