62 research outputs found
Ecosustainable biomethane and fertilizerproduction through anaerobic co-digestionof animal manure and energy crops
No full textIn Italy and many European countries energy production from biomass is encouraged by strong economic subsidies so that renewable energy plants, anaerobic digestion plant producing biogas in particular, are getting large diffusion. Nevertheless, it is necessary to define the environmental compatibility as well as technological and economic issues dealing with the emerging renewable energy scenario. This evaluation should take into account global parameters as well as environmental impacts at regional and local scale coming from new polluting emissions. The environmental balances regarding new energy plants are of primary importance within very polluted areas such as Northern Italy where air quality limits are systematically exceeded, in particular for PM10, NO2 and ozone. The most important environmental shortcomings that should be solved or at least minimized as far as biogas production and utilisation are concerned are: 1. macro-pollutants emissions from biogas engine at the local scale and low fuel utilization index (biogas plants generally don't recover all thermal energy at disposal); 2. indirect GHG emissions, mainly involving post-methanation emissions from the digestate storage; 3. ammonia emissions from the storage and land spreading of digested materials, low fertilising efficiency of manure and digestate, nitrate contamination of groundwater. The described emissions and energy inefficiency could involve negative environmental balances at the local scale, conflicting with the possible benefits arising from biomass energy production. An alternative technological choice for biogas valorisation could be biomethane production (also called green gas) through biogas purification and upgrading processes in order to remove CO2 and trace components. Biomethane production and its injection into natural gas grid (or its use as a transport vehicle fuel) could bring about strong energy and environmental benefits such as higher energy efficiencies and lower specific emissions (district heating CHP units, combined cycle gas turbines, methane powered vehicles). The present study mainly aims at analysing biogas upgrading techniques under the aspects of energy consumptions and environmental sustainability, with a specific focus on minimizing methane losses from the process by means of suitable design and operative choices (temperature, pressures, sorbents, recirculation strategies, etc.) that are fully described and simulated. The considered upgrading techniques are based on the principles of physical and chemical absorption and pressure/vacuum swing adsorption (PSA). The analysis highlights that there are strong differences among the examined upgrading techniques, as far as specific sorbent flows, absorbing tower dimensions, methane losses, power required, recoverable heat and environmental impacts (use of resources, gaseous releases of odorous and polluting molecules, GHG balances) are concerned. In particular, all the analysed upgrading techniques could be designed in order to achieve very low methane slip, below 0.1%, except PSA for which methane losses are hardly reducible below 2%, even at very high energy consumptions. The actual range of methane slip for the considered technologies is 0.1÷5% whereas the energy consumption to upgrade biogas lies in the range 0.05÷0.54 kWhe/m3 of raw biogas. The following analysis reports also some economic evaluations including electric energy costs, thermal energy requirements, biomethane sale incomes and external costs due to environmental impacts of biogas production+upgrading techniques. Within the described cost-benefit approach, the best overall balances seems to be assured by absorption with DEPG and chemical absorption with MEA. Finally, the last part of the present work shows a technical analysis of a specific digestate treatment process that could help reaching both the reduction of GHG and ammonia emissions and, at the same time, the production of fertilizers. The present analysis therefore confirms that biogas/biomethane technology is absolutely ready and suitable to reach very high levels of productivity, efficiency and environmental performances at sustainable costs and the right technological approach could solve many environmental problems regarding nitrate contamination of groundwater, ammonia emissions and global warming issue
Humboldt penguins’ feathers as bioindicators of metal exposure
No full textAvian feathers have the potential to accumulate trace elements originating from contaminated food and polluted environments. In fact, in feathers, metals bind to keratin, a sulphur-containing protein for which several metals have a strong affinity. Here, the concentrations of 18 essential and non-essential elements were investigated in a Humboldt penguin (Spheniscus humboldti) colony housed at the Acquario di Cattolica (Italy). This species is listed as vulnerable in the Red List of the International Union for Conservation of Nature. According to the literature, there is usually a link between metal levels in the diet of birds and levels detected in their feathers. Thus, metals were also determined in the penguins’ food (capelin, Mallotus villosus). We hypothesize that the controlled conditions in which birds are kept in captivity, and the homogeneous diet that they follow could allow a better understanding of metal bioaccumulation (such as mercury) or bio-dilution (such as arsenic) in the marine food chain, indicated by penguins’ feathers. Moreover, comparisons with our previous investigations performed on an ex-situ African penguin (Spheniscus demersus) colony suggest that penguins living indoors have lower body burden of metals than those living outdoors. Indeed, environmental contaminants usually found in areas subjected to anthropogenic impact, where zoos and aquaria are often located, are not accumulated to levels of concern
Armellinoite-(Ce), Ca4Ce4+(AsO4)4⋅H2O, a new mineral species isostructural with pottsite, (Pb3Bi)Bi(VO4)4⋅H2O
No full textArmellinoite-(Ce), ideally Ca4Ce4+(AsO4)4⋅H2O, is a new mineral discovered in Fe–Mn ore in metaquartzites of the Montaldo mine, Corsaglia Valley, Cuneo Province, Piedmont, Italy. It occurs as very small and rare, pale yellow to brown–yellow pseudo-octahedral translucent crystals hosted by a matrix of quartz, hematite, cryptomelane/hollandite, tilasite, muscovite, braunite and montmorillonite. The mineral is translucent, with white streak and has a resinous to vitreous lustre. It is brittle with irregular fracture and fair cleavage parallel to {110} and {100}. Estimated Mohs hardness is ~3–3.5. Calculated density is 4.29 g⋅cm–3. Armellinote-(Ce) is uniaxial (–), ω = 1.795(5), ɛ = 1.765(5) (white light), non-pleochroic and non-fluorescent. Chemical point analyses by WDS-EPMA yielded the empirical formula (based on 17 O+F anions): A(Ca3.89Th0.08Sr0.02La0.03)Σ4.02B(Ce4+0.76Nd0.13Y0.08Gd0.03Sm0.02Pr0.01Dy0.01Ho0.01)Σ1.05[(As4.00P0.01)Σ4.01O4]4⋅(H2O0.85F0.15)Σ2.00. The presence of H2O was confirmed by Raman spectroscopy. The mineral is tetragonal, I41/a, with single-crystal unit-cell parameters a = 10.749(2), c = 12.030(2) Å and V = 1390.0(6) Å3, with Z = 4. The eight strongest X-ray powder diffraction lines are [d Å (Irel; hkl)]: 7.983 (36; 101), 4.443 (23; 2̄11), 2.957 (100; 3̄12), 2.398 (14; 420), 1.875 (22; 424, 325), 1.728 (19; 3̄16), 1.612 (13; 613) and 1.475 (26; 712, 552). The crystal structure (R1 = 0.0284 for 1275 unique reflections) has isolated TO4 (T = As5+) tetrahedra that link Ca2+- or Ce4+-centred polyhedra via common oxygen ligands to form 2D blocks or double-layered (DL) structural units parallel to (001). Armellinoite-(Ce) is isostructural with pottsite, ideally (Pb3Bi)Bi(VO4)4⋅H2O, and closely related to a larger number of anhydrous synthetic compounds. The mineral is named after the mineral collector Gianluca Armellino (b. 1962), who collected the discovery sample
Feathers of Humboldt penguin are suitable bioindicators of Rare Earth Elements
No full textRare earth elements (REEs), also called lanthanides, are emerging contaminants worldwide, due to their unique physical and chemical characteristics that make them essential in a variety of industrial applications. However, there is still a gap in the knowledge of occurrence and accumulation of REEs in biota, and no investigations have yet been performed in penguin feathers, which have already been widely utilized as a non-invasive tool for the biomonitoring of trace elements. The concentrations of 16 REEs were investigated in a colony of Humboldt penguins (Spheniscus humboldti)housed at the Acquario di Cattolica (Italy). Multielement determination of REEs was performed by an Inductively Coupled Plasma-Mass Spectrometer after a microwave digestion of feathers. As this colony lives indoors in a controlled environment, it was the ideal choice for studying lanthanide occurrence in penguin feathers. Since there is a strict link between metal levels in feathers and the diet of penguins, their food (capelin)was also tested for REEs. Chondrite normalized values revealed the same pattern for REEs in feathers and fish, but REE concentrations were an order of magnitude higher in penguin feathers, demonstrating the suitability of this tissue as a bioindicator of REEs
Aux frontières de quoi ? Situations d ' e x p e r t i s e , débordement et cadrage de l'action publique
No full textDiscutants : Thierry Berthet, chargé de recherche, SPIRIT, Amandine Brizio et Agathe Devaux-Spatarakis, doctorantes SPIRITNational audienc
Antioxidant response versus selenium accumulation in the liver and kidney of the Siberian sturgeon (Acipenser baeri).
No full textThe aim of this study was to examine the effects of selenium on concentrations of metabolites and
enzyme activities acting as antioxidant markers in liver and kidney of Siberian sturgeon Acipenser baeri.
Sturgeons were fed selenium cysteine for 30 and 60 d at 1.25, 5, 20 mg Se kg1. Selenium level in the control
feed was 0.32 mg kg1. Se concentration was measured in liver, kidney and muscle of every specimen.
Sturgeon accumulated Se in tissues with a clear dose-response relationship and the highest Se
concentration was recorded in liver. This outcome is lined up with the findings obtained on the antioxidant
markers evaluated in both tissues, and in which a dose-response for several biomarkers was
recorded in liver. The superoxide dismutase activity in Se-treated fish was generally induced, while catalase
activity was lower in liver or unaltered in kidney. The concentrations of glutathione S-transferase,
glutathione reductase and total glutathione responded differently for both tissues and were induced in a
different way at both endpoints. No changes of glyoxalase I activity were noted for both Se-treated tissues,
while for glyoxalase II enzyme in liver a dose-related pattern was found showing a reversible effect
(decreased and increased counteractive response) only in the 5 mg kg1 group. Moreover, the highest Se
concentrations did not cause marked changes in malondialdehyde levels of liver and kidney. The
enhancement of glutathione peroxidase activity in Se-treated sturgeon might have prevented the lipid
peroxidation in both tissues, providing to the Siberian sturgeon a great defense ability versus the prooxidant
effect of selenium
Histopathological evaluation of gonadal anomalies in Mugilidae species as a potential indicator of endocrine disruptor’s presence in Sardinian lagoons.
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Ecología térmica de Liolaemus cuyumhue (Squamata: Liolaemini), el endemismo amenazado del Bajo de Añelo, Neuquén
No full textLa forma en que los vertebrados ectotérmicos explotan los recursos térmicos tiene implicancias importantes en la manera en que utilizan su hábitat, cómo se distribuyen geográficamente y también sirve para establecer su vulnerabilidad al calentamiento global producto del cambio climático. El objetivo de este trabajo fue evaluar las relaciones térmicas y eficiencia termorregulatoria de Liolaemus cuyumhue, especie psammófila endémica considerada críticamente amenazada (UICN) y vulnerable (AHA). Se registró en campo la temperatura corporal (Tb), operativa (Te) y las micro-ambientales de aire (Ta) y sustrato (Ts). En laboratorio, se determinó la temperatura preferida (Tpref), temperatura crítica máxima (CTmax) y mínima (CTmin). Sobre la base de estos parámetros, calculamos la eficiencia termorregulatoria (E), tolerancia al calentamiento y el margen de seguridad térmica (TSM). Se encontró una asociación significativa de la Tb con las temperaturas micro-ambientales Ta y Ts (R2Ta= 0.70, R2Ts= 0.32; P 0.05) entre la Tb de campo (35.84°C) y la temperatura preferida (35.79°C). La eficiencia termorregulatoria (E= 0.75), indica que la especie sería un termorregulador eficiente en un ambiente con baja calidad térmica (db= 4.09). De acuerdo a los índices de tolerancia al calentamiento (2.28°C) y el TSM (6.32°C) se infiere que L. cuyumhue se vería perjudicada ante un aumento de la temperatura promedio del ambiente de 4 a 6°C según las predicciones para finales del presente siglo. Considerando la distribución restringida de L. cuyumhue y la gran concentración de actividades antrópicas en su hábitat que disminuyen la disponibilidad de refugios térmicos, resulta necesario discutir la implementación de medidas concretas para la conservación de la especie.Fil: Brizio, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Comahue. Facultad de Ciencias del Ambiente y la Salud; ArgentinaFil: Gómez Alés, Carlos Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; ArgentinaFil: Pérez, D. R.. Universidad Nacional del Comahue. Facultad de Ciencias del Ambiente y la Salud; ArgentinaFil: Avila, Luciano Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaXX Congreso Argentino de HerpetologíaSan JuanArgentinaUniversidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de BiologíaAsociación Herpetológica Argentin
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