Misure di flusso di Geo-gas (CO2, etc…) con il “Sistema SAP” con polle gassose a flusso macroscopico”. I casi della Val Comino e Palidoro

L’UR 11 del Progetto DPC 2005-2007 V5 “Diffuse Degassing in Italy” ha configurato e testato un sistema in grado di effettuare misure di flusso di emissioni gassose naturali “ad alta portata” (con particolare riferimento alla CO2, ma anche di altri geo-gas), disponendo dei dati di composizione chimica del gas stesso, denominandolo SAP = “Sistema di misura di flusso geo-gas ad Alta Portata”. Ci si focalizza in questo II anno di progetto su emissioni “eclatanti”, associate a piccoli laghetti o “polle” naturali, in zone dove storicamente si è verificata l’emissione più o meno marcata e continua di flussi gassosi; in particolare iniziando nelle aree della Val Comino (Basso Lazio) e di Palidoro (Alto Lazio). L’applicazione delle metodologie segue il lavoro intrapreso da Rogie et al. (2000), con in più una maggiore versatilità rispetto a quest’ultimo lavoro, dovuta ad una diversa geometria del sistema convogliatore del gas da allocarsi sull’emissione gassosa ed all’utilizzo di materiali più adattabili alle varie condizioni di campagna. Il sistema è stato concepito inoltre con l’intenzione di quantizzare con precisione non solo i flussi di CO2, ma anche degli altri geo-gas, semplicemente diminuendo il diametro del tubo di uscita del gas. Nella presente relazione si discute solamente del flusso di CO2, ma conoscendo la concentrazione degli altri gas delle medesime polle studiate si risale facilmente ai flussi degli altri gas (H2S, CH4, etc…). La CO2 presenta effetti tossici acuti immediati sull’apparato respiratorio: per tempi di esposizione fino a 15 minuti e per concentrazioni in atmosfera che raggiungono il 5% la CO2 provoca vasocostrizione ed incremento della attività respiratoria; per concentrazioni >10% provoca paralisi respiratoria e svenimento; mentre per concentrazioni > 25% determina il decesso immediato. Tali effetti sono accresciuti dal fatto che la specie non presenta colore ed odore con la conseguente impossibilità di essere notata per tempo dagli organi sensoriali. Inoltre, essendo più pesante dell’aria, tende a formare delle dense nubi tossiche che seguono la topografia del luogo accumulandosi per lo più nelle zone depresse prossime alla zona di emissione. E’ risultato per tanto urgente, in linea con il Progetto DPC 2005-2007 V5, quantificare i flussi giornalieri di gas emesso dalle macro-polle emissive di CO2 come quella di Palidoro e della Val Comino. Visto l’alto grado di tossicità dei gas emessi, manifestato dalla presenza più o meno continua di animali morti nei siti d’indagine, tale ricerca ha come priorità di protezione civile la valutazione dei valori di flusso di CO2 e delle sue implicazioni in termini di “pericolosità” e “valore esposto” nei riguardi di persone ed animali residenti nelle zone in esame; anche considerando il ruolo di carrier dell’anidride carbonica per altri geogas pericolosi per la salute umana come ad esempio il Radon (Pizzino et. al. 2002; Voltaggio, 2003). Già in passato, altri siti degassanti del territorio nazionale, hanno determinato incidenti letali anche ai danni di persone (Chiodini & Frondini, 2001; Pizzino et al., 2000; Voltaggio 2003). La pericolosità di tali fenomeni di degassamento è poi accresciuta dalla presenza di zone geomorfologicamente depresse: le stesse “polle” ed i solchi e i rivoli prossimi alle zone di emissione. Tali elementi morfologici accumulano e veicolano le miscele gassose a CO2 dominante che essendo più pesanti dell’aria tendono a stagnare nei primi strati di atmosfera a contatto con il suolo. In tal senso anche le condizioni di circolazione atmosferica locale giocano un importante ruolo nel favorire o sminuire l’accumulo dei gas. La presente relazione descrive le prime 2 esperienze di misura di flusso tramite quello che definiamo “Sistema di misura di flusso geo-gas ad Alta Portata” (SAP). Il SAP è come si diceva concettualmente analogo al sistema GCD (Inflatable gas Capturing Device) descritto da Rogie et al., (2000)

A match coefficient approach for damage imaging in structural components by ultrasonic synthetic aperture focus

Ultrasonic Synthetic Aperture Focus (SAF) techniques are commonly used to image structural defects. In this paper, a variation of SAF based on ideas borrowed from Matched Field Processing (MFP) is evaluated to reduce artifacts and sidelobes of the resulting images. In particular, instead of considering the full RF ultrasonic waveforms for the SAF time backpropagation, only selected features from the waveforms are utilized to form a “data vector” and a “replica” (expected) vector of MFP. These vectors are adaptive for the pair of transmitter-receiver and the focus point. The image is created as a matched filter between these two vectors. Experimental results are shown for an isotropic and homogenous metallic plate with simulated defects, probed by six piezoelectric patches used as receivers or transmitters

A simple and sensitive gas chromatography–electron capture detection method for analyzing perfluorocarbon tracers in soil gas samples for storage of carbon dioxide

Co-injection of a conservative tracer during the geological sequestration of CO2 can imprint a marker to the injected gas that can be easily recognized during soil gas surveys in case of CO2 leakage from the reservoir toward the surface. In this work, an ultra-trace detection method, based on gas chromatography with electron capture detection for analyzing perfluorocarbon tracers (PFTs) in soil gas samples was optimized. Three totally fluorinated cycloalcane compounds consisting of five and six atom carbon rings were selected for this purpose. We evaluated the feasibility of collecting PFTs on adsorbent tube packed with a commercial graphitized carbon black (Carbotrap™ 100) sampling 2 L of soil gas. The sorbent tubes were then analyzed by using a two-stage thermal desorption process. The developed method allows to quickly determine these compounds at very low fL/L level, method identification limits ranged from 1.3 to 5.8 fL/L. Moreover, it shows good precision, evaluated by within-day and between-day studies. A preliminary survey of the PFT soil gas background concentrations, conducted by analyzing some soil gas samples collected in two different areas in Central Italy and in the Po Plain, ascertained the PFT background concentration lower than MIL

Geochemistry of fluids discharged over the seismic area of the Southern Apennines (Calabria region, Southern Italy): Implications for Fluid-Fault relationships

The first comprehensive geochemical data-set of the fluids circulating over a 14,000 km2-wide seismicprone area of the Southern Apennines, Calabria Region (Italy), is presented here. The geochemical investigations were carried out with the twofold aim of constraining the origin and interactions of the circulating fluids and to investigate possible relationships with local faults. Sixty samples of both thermal and cold waters were collected, from which the dissolved gases were extracted. The geochemical features of the water samples display different types and degrees of water–rock interactions, irrespective of the outlet temperature. The calculated equilibrium temperatures of the thermal waters (60–160 C) and the low heat flow of thewhole study area, are consistent with a heating process due to deep water circulation and rapid upflow through lithospheric structures. The composition of the dissolved gases reveals that crustal-originating gases (N2 and CO2-dominated) feed all the groundwaters. The 3He/4He ratios of the dissolved He, in the range of 0.03–0.22Rac for the thermal waters and 0.05–0.63Rac for the cold waters (Rac = He isotope ratio corrected for atmospheric contamination), are mainly the result of a two-component (radiogenic and atmospheric) mixing, although indications of mantle-derived He are found in some cold waters. As the study area had been hit by 18 of the most destructive earthquakes (magnitude ranging from 5.9 to 7.2) occurring over a 280-a time span (1626–1908) in the Southern Apennines, the reported results on the circulating fluids may represent the reference for a better inside knowledge of the fault-fluid relationships and for the development of long-term geochemical monitoring strategies for the area

Theoretical Estimation of CO2 Compression and Transport Costs for an Hypothetical Carbon and Capture & Storage Requalification of the Saline Joniche Power Plant Project

SEI S.p.a. presented a project to build a 1320 MW coal-fired power plant in Saline Joniche, on the Southern tip of Calabria Region, Italy, in 2008. A gross early evaluation about the possibility to add CCS (CO2 Capture & Storage) was performed too. The project generated widespread opposition among environmental associations, citizens and local institutions in that period, against the coal use to produce energy, as a consequence of its GHG clima-alterating impact. Moreover the CCS (also named Carbon Capture & Storage or more recently CCUS: Carbon Capture-Usage-Storage) technology was at that time still an unknown and “mysterious” solution for the GHG avoiding to the atmosphere.   The present study concerns the sizing of the compression and transportation system of the CCS section, included in the project presented at the time by SEI Spa; the sizing of the compression station and the pipeline connecting the plant to the possible Fosca01 offshore injection site previously studied as a possible storage solution, as part of a coarse screening of CO2 storage sites in the Calabria Region. This study takes into account the costs of construction, operation and maintenance (O&M) of both the compression plant and the sound pipeline, considering the gross static storage capacity of the Fosca01 reservoir as a whole as previously evaluated

The increasing temperature as driving force for spatial distribution patterns of Parapenaeus longirostris (Lucas 1846) in the Strait of Sicily (Central Mediterranean Sea)

The deep-water rose shrimp Parapenaeus longirostris (DPS), a demersal decapod representing the most important component of crustacean landings in the Mediterranean Sea, has been suggested as a species that may exhibit temperature-driven changes in the spatio-temporal dynamics. Considering that Mediterranean waters are warming up faster than oceans, understanding the relationships of DPS populations with temperature variations and the related changes in spatial patterns is absolutely key for its management. Using a long-term dataset covering 13-years from scientific surveys (International Bottom Trawl-Surveys in the Mediterranean, MEDITS; Italian national trawl surveys, GRUND) in the Strait of Sicily (central Mediterranean Sea), the annual DPS spatial patches and the depth distribution were investigated using geostatistical and quotient analyses. The patches dimension and depth range occupation were then related to sea temperature by using linear regression analysis. Results showed that both the dimension of DPS spatial patches and the depth distribution range occupied increased concurrently with temperature. Our findings corroborate that the ongoing sea warming widen areas suitable for this species and in which it can expand its spatial distribution

The application of soil gas technique to geothermal exploration:study of “hidden” potential geothermal systems

Geochemical studies were conducted using soil-gas and flux surveyings for locating both permeable zones in buried reservoirs and the presence of possible gaseous haloes linked to active geothermal systems. In this work we focused our interest on the distribution of soil-gas concentrations (Rn, Th, He, H2, O2, N2, CO2, CH4 and H2S) in the soil air of the Tetitlan area (Nayarit, Mexico) considered a potential thermal field and characterized by scarcity of surface manifestations. A total of 154 soil-gas samples and 346 CO2 and CH4 flux measurements were collected in an area of about 80 square kilometres. The performed soil-gas and flux geochemical surveys highlighted a general rising patterns linked to local fault system, with the important implication that the highest CO2 and CH4 fluxes, as well as Rn concentrations, could be used in undeveloped geothermal systems to identify main upflow regions and areas of increased and deep permeability

The application of soil gas technique to geothermal exploration:

Geochemical studies were conducted throughout soil gas and flux surveying for locating both permeable zones in buried reservoirs and the presence of possible gaseous haloes linked to active geothermal systems. In this work we focused our interest on the distribution of soil gas concentrations (Rn, Th, He, H2, O2, N2, CO2, CH4 and H2S) in the soil air of the Tetitlan area considered a potential thermal field and characterized by scarcity of surface manifestations. Radon is used as a tracer gas to provide a qualitative idea of gas transfer (velocity and flux), carbon dioxide and methane are believed to act as carriers for other gases (i.e., Rn and He), helium and hydrogen are used as shallow signals of crustal leaks along faults (Ciotoli et al., 2005). Methane is also considered both a characteristic biogenic indicator of organic matter deposits and a tracer of major crustal discontinuity. A total of 154 soil gas samples were collected in an area of about 80 square kilometres. The same area was investigated throughout a total of 346 of CO2 and CH4 flux measurements

Development of groundwater radon continuous monitors: Comparison between α scintillation and γ spectrometry systems

Two temporised continuous monitoring systems, designed to measure the radon concentration in natural environments, mainly groundwater, were assembled, tested and cross-check compared, evaluating the background noise, sensitivity, calibration values and soundest application in the Earth Science framework. The two systems have been customised by DINCE Laboratory, based on best-fitting criteria selected according to the ING laboratory, partially in the frame of two EC funded, Geochemical Seismic Zonation (GSZ) and Automatic Geochemical Monitoring of Volcanoes, addressed to earthquake prediction research and prototype developing, aimed to seismic and volcanic risks surveillance. Following best-fitting criteria of the radon monitoring aimed to natural risk research, both systems are operative by discrete temporised sampling of an aliquot of groundwater, with a minimal interval of six hours. During their functioning at the ENEA Centre of Frascati (Rome), the test-site chosen, both systems provided a continuous and reliable response

Nest guarding behaviour of a temperate wrasse differs between sites off Mediterranean CO2 seeps

Organisms may respond to changing environmental conditions by adjusting their behaviour (i.e., behavioural plasticity). Ocean acidification (OA), resulting from anthropogenic emissions of carbon dioxide (CO2), is predicted to impair sensory function and behaviour of fish. However, reproductive behaviours, and parental care in particular, and their role in mediating responses to OA are presently overlooked. Here, we assessed whether the nesting male ocellated wrasse Symphodus ocellatus from sites with different CO2 concentrations showed different behaviours during their breeding season. We also investigated potential re-allocation of the time-budget towards different behavioural activities between sites. We measured the time period that the nesting male spent carrying out parental care, mating and exploring activities, as well as changes in the time allocation between sites at ambient (~400 μatm) and high CO2 concentrations (~1000 μatm). Whilst the behavioural connectance (i.e., the number of linkages among different behaviours relative to the total amount of linkages) was unaffected, we observed a significant reduction in the time spent on parental care behaviour, and a significant decrease in the guarding activity of fish at the high CO2 sites, with a proportional re-allocation of the time budget in favour of courting and wandering around, which however did not change between sites. This study shows behavioural differences in wild fish living off volcanic CO2 seeps that could be linked to different OA levels, suggesting that behavioural plasticity may potentially act as a mechanism for buffering the effects of ongoing environmental change. A reallocation of the time budget between key behaviours may play a fundamental role in determining which marine organisms are thriving under projected OA