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Thermal waters near the city of Viterbo (Central Italy) are known to show high As contents (up to 600 µg/l). Travertine is precipitated by these waters, forming extended plateau. In this study, we determine the As content, speciation and bioaccessibility in soil and travertine samples collected near a recreational area highly frequented by local inhabitants and tourists to investigate the risk of As exposure through accidental ingestion of soil particles. (Pseudo)total contents in the studied soils range from 17 to 528 mg/kg, being higher in soil developed on a travertine substrate (197 ± 127 mg/kg) than on volcanic rocks (37 ± 13 mg/kg). In travertines, most As is bound to the carbonatic fraction, whereas in soil the semimetal is mostly associated with the oxide and residual fractions. Accordingly, bioaccessibility (defined here by the simplified bioaccessibility extraction test, SBET; Oomen et al., 2002.) is maximum (up to 139 mg/kg) for soil developed on a travertine substrate, indicating a control of calcite dissolution on As bioaccessibility. On the other hand, risk analysis suggests a moderate carcinogenic risk associated with accidental soil ingestion, while dermal contact is negligible. By contrast, ingestion of thermal water implies a higher carcinogenic and systemic health risk.

We present the first real attempt to directly and continuously measure GEM through a Lumex RA-915 M, designed for real-time detection of mercury vapor, mounted on an UAV (Unmanned Aerial Vehicle, namely a heavy-lift octocopter), inside and outside the former Hg-mining area of Abbadia San Salvatore (Mt. Amiata, Italy), known as a GEM source. We tested the effectiveness of the UAV-Lumex combination at different heights in selected sites pertaining to both mining facilities and surrounding urban zones, shedding light on the GEM spatial distribution and concentration variability. The Lumex great sensitivity and the octocopter optimal versatility and maneuverability, both horizontally and vertically, allowed to depict the GEM distribution in the atmosphere up to 60 m above the ground. The acquisition system was further optimized by: i) synchronizing Lumex and UAV GPS data by means of a stand-alone GPS that was previously synchronized with Lumex; ii) using a vertical sampling tube (1.20 m high) connected to the Lumex inlet to overcome the rotors strong airflows and turbulence that would have affected GEM measurements; iii) supplying the octocopter with batteries for power supply to avoid the release of exhaust gases; iv) taking the advantage of the UAV ability to land in small spaces and stop at selected altitudes. The resulting dot-map graphical representations, providing a realistic 3D picture of GEM vertical profiling during the flights in near real-time, were useful to verify whether the guideline concentrations indicated by competent authorities were exceeded. The results showed that the GEM concentrations in the urban area, located a few hundred meters from the mining structures, and close to already reclaimed areas remained at relatively low values. Contrarily, GEM contents showed significant variations and the highest concentrations above the facilities containing the old furnaces, where increasing GEM concentrations were recorded at decreasing heights or downwind.

The link between carbon dioxide diffuse degassing and its structural control was examined in the Caviahue – Copahue Volcanic Complex, over an area of approximately 10 km 2 that encompasses five hydrothermal sites, namely, Anfiteatro, Copahue town, Las Maquinitas I, Las Maquinitas II and Las Máquinas. Both geochemical and structural approaches were applied in order to investigate the structural scenario releasing hydrothermal fluids in this area. Also, the first isotopic analysis of soil CO 2 degassing in the Andean region is presented. The geochemical analysis shows well-defined CO 2 diffuse degassing structures in Copahue town, Las Maquinitas I, Las Maquinitas II and Las Máquinas hydrothermal sites. Soil diffuse CO 2 is fed by multiple sources: a deep, magmatic – hydrothermal, source, a biogenic source and a mixed source. The structural analysis indicates the presence of an extensional regime that gives place to three structural trends, consisting of NE-SW trending normal faults, NW-SE sinistral strike-slip faults and ENE-WSW right lateral strike-slip faults. The comparison between diffuse degassing structures directions and faults directions suggests that there is a structural control on diffuse degassing. Diffuse CO 2 is released through an early extensional setting, and it is emitted through normal faults, strike-slip faults and through areas with higher structural damage, such as relay areas between fault segments and terminations of individual fault segments. Fil: Lamberti, María Clara Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Vigide, Nicolás Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Venturi, Stefanía. Consiglio Nazionale delle Ricerche; Italia Fil: Agusto, Mariano Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Yagupsky, Daniel Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Winocur, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Barcelona, Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Velez, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Cardellini, Carlo. Università di Perugia; Italia Fil: Tassi, Franco. Università degli Studi di Firenze; Italia

Travertines are continental carbonates that precipitate from spring waters, mainly due to CO2 degassing. They are widely quarried as building stone, which has led to numerous (often abandoned) travertine quarry outcrops. These and other outcrops, however, merely represent the surface expressions of the complex architecture of travertine bodies and their deep–rooted feeding systems. Integration of field observations and geochemical analyses with crucial subsurface geophysical data is required in order to fully understand travertine systems and their relationship to the local geological framework. Such a multi-methodological approach is illustrated here for the case of the abandoned Cukor quarry. Radio-magnetotelluric (RMT) and Electrical Resistivity Tomography (ERT) surveys provide unique insights into local tectonics, geobody architecture and the topography preceding travertine deposition. Altogether, the lens–shaped, isolated domal geobody with spring-proximal lithofacies and subvertical bedding, in addition to the contrasting geochemistry and age with surrounding travertine, enabled the unequivocal reconstruction of the dismantled Cukor fissure ridge. This study illustrates the high potential of this multi–methodological approach on poorly exposed, strongly weathered, quarried and tectonically deformed travertine bodies, and provides information on the complex feeding system beneath travertine deposits. Their reconstruction can be interpreted in light of the neo–tectonic expression of regional uplift, helps to complete the regional tectonic history and provides insights into older landscapes that lack preservation or would no longer be immediately recognized at the surface.

Alluvial sediments from the coastal area in southern Tuscany (Italy) characterized by a significant As anomaly (As >500 mg/kg) are subjected to seawater intrusion due to groundwater exploitation. Sequential extractions and kinetic experiments were carried out on Quaternary alluvial sediments to quantify the interaction between As oxianions (adsorbed on mineral surfaces) and Cl− in solutions and to establish if this mechanism may contribute to the release of As in groundwater. The natural water-rock interaction in the aquifer was simulated in two experiments by saturating the samples with four solutions with increasing chlorinity for different time. Firstly, a rapid change in the aquifer salinity (e.g. fast seawater intrusion, groundwater over pumping) was simulated by an interaction sediment/solution of 24 h. Solutions with Cl−≤2000 mg/L extracted up to 76 μg/kg of As, while seawater (Sol 4(24): Cl− ∼18,500 mg/L) extracted up to 161 μg/kg of As. In a second experiment, the ingression of water with increasing salinity in the acquifer, followed by the withdrawal of the water after progressively longer interaction times with the aquifer sediments, was simulated. The timing of the As-Cl reaction was constrained by saturating the samples with four solutions with increasing salinity (Sol1(84): Cl−∼0 mg/L; Sol2(84) Cl− = 250 mg/L; Sol3(84) Cl− = 2000 mg/L; Sol4(84): Cl− = 15,886 mg/L) that interacted with the sediment samples for longer saturation times (up to 21 days for each solution). After saturation with the previous three solutions up to 62 μg/kg of As were extracted by seawater, following a salinity increase from 2000 mg/L Cl to a chlorinity close to seawater, representing ∼60% of the exchangable As fraction in the sediments. Our results constrained the timing of sediment/solution interaction of As desorption and showed that after a rapid intrusion of seawater or after a relatively long period of interaction with saline solutions an aquifer with similar geology releases in groundwater concentrations of As exeeding the 10 μg/L limit for drinking water. Also, this study estimated the potential effects caused by the ingression of seawater in lowland alluvial coastal areas induced by groundwaters exploitation or by extreme weather events. Such information is crucial for management authorities to mitigate and predict the effects of As hazard in groundwater driven by changes in the environmental aquifer conditions (e.g. seasonal fluctuations of the water table and/or changes in salinity of coastal aquifers), which are becoming increasingly frequent as consequence of climate change.

In this study, we draw on a unique combination of well-resolved fault-slip data and earthquake focal mechanisms to constrain spatial variations in style of faulting in the obliquely extending Main Ethiopian Rift, East Africa. These data show that both boundary and internal faults - oblique and orthogonal to the plate divergence (PD) respectively - exhibit almost pure dip-slip motion, and indicate significant local deflection in orientation of the extension direction at rift margins. Scaled analogue models closely replicate the multidisciplinary observations from the rift and suggest that the process is controlled by the presence of a deep-seated, pre-existing weakness - oblique to the direction of PD - that is able to cause a local rotation in the orientation of the extension direction at rift margins. Minor counterclockwise block rotations are required to accommodate the difference in slip direction along the different fault systems, as supported by existing and new palaeomagnetic data from the rift.

This paper focuses on the chemical and isotopic features of dissolved gases (CH4 and CO2) from four meromictic lakes hosted in volcanic systems of Central-Southern Italy: Lake Albano (Alban Hills), Lake Averno Phlegrean Fields), and Monticchio Grande and Piccolo lakes (Mt. Vulture). Deep waters in these lakes are characterized by the presence of a significant reservoir of extra-atmospheric dissolved gases mainly consisting of CH4 and CO2. The delta C-13-CH4 and dD-CH4 values of dissolved gas samples from the maximum depths of the investigated lakes (from -66.8 to -55.6% V-PDB and from -279 to -195% V-SMOW, respectively) suggest that CH4 is mainly produced by microbial activity. The delta C-13-CO2 values of Lake Grande, Lake Piccolo, and Lake Albano (ranging from -5.8 to -0.4% V-PDB) indicate a significant CO2 contribution from sublacustrine vents originating from (1) mantle degassing and (2) thermometamorphic reactions involving limestone, i.e., the same CO2 source feeding the regional thermal and cold CO2-rich fluid emissions. In contrast, the relatively low delta C-13-CO2 values (from -13.4 to -8.2% V-PDB) of Lake Averno indicate a prevalent organic CO2. Chemical and isotopic compositions of dissolved CO2 and CH4 at different depths are mainly depending on (1) CO2 inputs from external sources (hydrothermal and/or anthropogenic); (2) CO2-CH4 isotopic exchange; and (3) methanogenic and methanotrophic activity. In the epilimnion, vertical water mixing, free oxygen availability, and photosynthesis cause the dramatic decrease of both CO2 and CH4 concentrations. In the hypolimnion, where the delta C-13-CO2 values progressively increase with depth and the delta C-13-CH4 values show an opposite trend, biogenic CO2 production from CH4 using different electron donor species, such as sulfate, tend to counteract the methanogenesis process whose efficiency achieves its climax at the water-bottom sediment interface. Theoretical values, calculated on the basis of delta C-13-CO2 values, and measured delta C-13(TDIC) values are not consistent, indicating that CO2 and the main carbon-bearing ion species (HCO3-) are not in isotopic equilibrium, likely due to the fast kinetics of biochemical processes involving both CO2 and CH4. This study demonstrates that the vertical patterns of the CO2/CH4 ratio and of delta C-13-CO2 and delta C-13-CH4 are to be regarded as promising tools to detect perturbations, related to different causes, such as changes in the CO2 input from sublacustrine springs, that may affect aerobic and anaerobic layers of meromictic volcanic lakes.

International audience; This paper investigates the influence exerted by brittle tectonic structures in the emplacement of granite plutons in contractional settings. We address both cases where contractional tectonics and magma intrusion are (1) coeval, to study how active contractional tectonics controls the transport of magma, and (2) diachronous, to study the role of pre-existing structures on the transport of magma. In light of new experimental models, we show that magma can rise along thrusts ramps and flats. This phenomenon occurs for both low-viscosity magma (basalts to andesite) and high-viscosity magma (dry granite). The experimental results also allow the evaluation of the role played by magma viscosity in determining pluton geometries. In addition, a review of literature demonstrates a spatial and causal relationship between granites and thrusts and highlights the geometric control of magma pathways in the pluton final shape. The abundance of subhorizontal and tabular granitic intrusions indicates that the location of inflating granitic sills along thrust flats can be common. We argue that active and pre-existing flats-and-ramps thrusts provide a preferential continuous planar anisotropy susceptible to become a granitic magma migration pathway.

Professional exposure to asbestos fibres is widely recognized as very dangerous to human health and for this reason many countries have banned their commercial uses. People, nevertheless, continue to be exposed to low dose of asbestos from natural and anthropogenic sources still in loco, for which the potential hazard is unknown. The aim of this research is to assess environmental exposure in an area with outcropping serpentinite rocks, which bear asbestos mineralizations, using sentinel animals which are a non-experimental animal model. We studied the burden of inorganic fibres in cattle lungs which come from two areas in Italy's Western Alps bearing serpentinitic outcrops: Susa Valley with a heavy anthropization and Lanzo Valleys, with a minor human impact. The identification and quantification of inorganic fibres were performed by Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS). In comparison to humans, studies of animals have some advantages, such as no occupational exposure or history of smoking and, in the case of cattle, a sedentary life restricted to one region. Results spotlight that over than 35% of inorganic fibres found both in Susa and Lanzo valleys, belong to asbestos mineralogical species (asbestos tremolite/actinolite, chrysotile s.s., asbestos grunerite, crocidolite). We also observed a higher concentration of artificial fibrous products in Susa samples showing a correlation with the level of anthropization. These results confirm that sentinel animals are an excellent model to assess breathable environmental background because it is possible to eliminate some variables, such as unknown occupational exposure. © 2008 Elsevier B.V. All rights reserved.

The inner sector of the Eastern Carpathians displays a large number of Na–HCO 3 , CO 2 -rich, meteoric-originated cold springs (soda springs) and bore wells, as well as dry mofettes. They border the southern part of the Pliocene–Quaternary Calimani–Gurghiu–Harghita (CGH) calc-alkaline volcanic chain. Both volcanic rocks and CO 2 -rich emissions are situated between the eastern part of the Transylvanian Basin and the main east Carpathian Range, where active compression tectonics caused diapiric intrusions of Miocene halite deposits and associated saline, CO 2 -rich waters along active faults. The regional patterns of the distribution of CO 2 in spring waters (as calculated p CO 2 ) and the distribution pattern of the 3 He/ 4 He ratio in the free gas phases (up to 4.5 R m / R a ) show their maximum values in coincidence with both the maximum heat-flow measurements and the more recent volcanic edifices. Moving towards the eastern external foredeep areas, where oil fields and associated brines are present, natural gas emissions become CH 4 -dominated. Such a change in the composition of gas emissions at surface is also recorded by the 3 He/ 4 He ratios that, in this area, assume ‘typical’ crustal values ( R m / R a =0.02). In spite of the fact that thermal springs are rare in the Harghita volcanic area and that equilibrium temperature estimates based on geothermometric techniques on gas and liquid phases at surface do not suggest the presence of shallow active hydrothermal systems, a large circulation of fluids (gases) is likely triggered by the presence of mantle magmas stored inside the crust. If total 3 He comes from the mantle or from the degassing of magmas stored in the crust, CO 2 might be associated to both volcanic degassing and thermometamorphism of recently subducted limestones.