Elevated trace metals and REE contents in the CO2-rich groundwaters of Florina (N. Greece) a natural analogue of carbon storage systems

The Florina basin, being the main commercial source of CO2 in Greece, represents a good natural analogue for the study of the impact of geologic carbon storage. It is part of a NNW-SSE trending graben filled with ~600 m Plio-Pleistocene fluvial and lacustrine deposits. The area is characterized by the upflow of great quantities of geogenic CO2 probably associated to presently extinct Quaternary volcanic activity. The gas originates mainly from crustal sources but has also a minor (~10%) mantle contribution. This strong upflow of nearly pure CO2 can be recognized in industrially exploitable gas reservoirs, high pCO2 shallow groundwaters and surface gas manifestations. But the increased CO2 content has a deleterious impact on groundwater quality. Due to the increased aggressiveness of the low-pH CO2-rich waters with respect to the aquifer rocks, EU drinking water limits are exceed for many parameters (e.g. Electric conductivity, pH, Na+, SO42-, F-, Al, B, Ba, Fe, Mn and Ni). Considering the additional impact of widespread agricultural activities, which is recognizable in sometimes elevated NO3- contents, only few of the sampled waters (4 out of 40) could be used for potable purposes. Aquifer waters are also characterized by high REE contents with ΣREE up to ~12 µg/l. Shale-normalized profiles show positive La and Y anomalies and Ce negative anomalies probably indicating a main derivation from iron oxyhydroxide dissolution. The positive Eu anomaly evidences also carbonate dissolution while the enrichment in HREE is probably due to the abundant presence of HCO3-, which increases HREE solubility through complexation. Future developments of carbon capture and storage programs in the nearby sedimentary basin of Ptolemais and Servia have to carefully take in account the possible deterioration of their groundwater resources due to CO2 leaks from the storage reservoirs

Early detection of biochemically occult autonomous thyroid nodules

Objective: Autonomously functioning thyroid areas may be associated with subclinical or overt hyperthyroidism, but may exist even in the presence of normal TSH. This study was aimed at comparing the rate of autonomously functioning areas and their cardiac sequelae in patients with nodular goitre studied with the usual and a novel approach. Design and methods: In total 490 adult outpatients with thyroid nodular goitre, living in a mild iodine-deficient area, were selected in our referral centre for thyroid diseases from 2009 to 2014 on the basis of a suspicion of thyroid functional autonomy. They were divided in three groups according to a non-conventional approach (excessive response to thyroxine treatment: group 1) or conventional approach (low/normal TSH with clinical suspicion or low TSH: groups 2 and 3). All patients of the study with the suspicion of thyroid functional autonomy underwent thyroid scan with radioactive iodine (I131) uptake (RAIU). Results: The percentage of confirmed thyroid functional autonomy was 319/490, being significantly higher in group 3 than in groups 1 and 2 (81.5 vs 64.7 vs 52.6%; chi-square P < 0.0001). However, the diagnosis with non-conventional approach was made at a significant earlier age (P < 0.0001). Cardiac arrhythmias as well as atrial fibrillation were similarly detected by conventional and non-conventional approaches (chi-square test: P = 0.2537; P = 0.8425). Conclusions: The hyper-responsiveness to thyroxine treatment should induce the suspicion of thyroid functional autonomy at an early stage, allowing to detect autonomous functioning areas in apparently euthyroid patients

Fractura Supracondílea de Humero en Niños: (estudio de la Rigidez Postquirúgica del Codo en 100 Casos Intervenidos a través de un Abordaje Posterior)

El tratamiento de las fracturas supracondíleas de húmero desplazadas en niños mediante reducción abierta y fijación interna es un procedimiento poco utilizado y que no goza del favor de la mayoría de los cirujanos ortopédicos, debido principalmente a la pérdida permanente de movilidad en el codo que se atribuye a esta técnica. Según algunos autores ésta pérdida es mayor aún si se utiliza un abordaje posterior. Se presenta una importante casuística (100 casos) de fracturas muy desplazadas que han sido tratadas mediante reducción abierta y fijación por vía posterior y revisadas a largo plazo. La rigidez postquirúrgica encontrada es en general leve, e inferior si se utiliza un abordaje quirúrgico que respete la integridad anatómica del músculo tríceps.Treatment of displaced supracondylar fractures of the humerus in children by open reduction and internal fixation is a little-used therapeutic method and ill-advised by many authors owing to permanent stiffness of the elbow using this procedure. An important series of 100 very displaced fractures treated by open reduction and fixation from a posterior approach and is slight and less using a surgical approach which respects the anathomic of triceps muscle

The fluids’ geochemistry along the "Sperchios Basin - Northern Evoikos Gulf" Graben, a geodynamically complex area of Central Greece

The study area is a 130 km long fast spreading graben in Central Greece. Its complex geodynamical setting includes both the presence at depth of a subduction slab responsible for the recent (Quaternary) volcanic activity in the area and the western termination of a tectonic lineament of regional importance (the North-Anatolian fault). Its high geothermal gradient is evidenced by the presence of many thermal springs with temperatures from 19 to 82 C, issuing along the normal faults bordering the graben. In the period 2004-2012 about 50 gas and water samples have been collected and their chemical and isotopic analysis revealed a wide range of compositions. Going from west to east the gas composition changes from CH4- to CO2-dominated passing through mixed N2- CH4 and N2-CO2 compositions, while at the same time the He isotopic composition goes from typical crustal values (0.05 R/Ra) up to 0.87 R/Ra (corrected for air contamination), showing in the easternmost sites a small but significant mantle input. Isotopic composition of CH4-C indicates a thermogenic origin for the CH4-rich samples and hydrothermal origin for the remaining samples. Positive 15N values indicate a contribution of crustal derived nitrogen for the N2-rich samples. The 13C values of most the CO2-enriched samples show a mixed origin (mantle and marine carbonates). Also the chemical composition of the waters shows differences along the graben and two main groups can be separated. The first, represented by dilute waters (E.C. < 600 S/cm), is found in the westernmost sites characterised by the presence of CH4-rich and mixed N2-CH4 gases. The remaining waters display higher salinities (E.C. from 12 to 56 mS/cm) due to the mixing with a modified marine component. Only the water composition of easternmost sites in the Giggenbach’s cation triangular graph plots in the field of the partially equilibrated waters giving estimated temperatures at depth of 150-160 C.PublishedVienna, Austria4.5. Studi sul degassamento naturale e sui gas petroliferiope

GROUNDWATER QUALITY ISSUES IN THE FLORINA AREA (N. GREECE)

The Florina basin developed in the Pelagonian Zone, the westernmost zone of the Internal Hellenides, in response to NE–SW extension in the Late Miocene and to a subsequent Pleistocene episode of NW–SE extension. Continuous sedimentation resulted in the accumulation of a 560 m thick succession of Late Miocene to Early Pleistocene lake sediments with intercalated lignites and alluvial deposits. The presence of intercalated volcanic ash beds of Pliocene age evidences volcanic activity related to the exstensional tectonics. Groundwaters in the central part of the Florina plain display high levels of dissolved gases, which often separate in a free gas phase. Their composition is dominated by carbon dioxide, which accounts for 85-99% of these gases. Apart from small amounts of atmospheric gases, minor components are CH4 (0.05-0.4%) and He (3-30 ppm). Carbon isotopic composition ranging from –1.6 to 0.3‰ (vs. VPDB) testifies for a deep (magmatic-hydrothermal) origin of CO2 and also He isotopic composition (0.24-0.55 R/Ra) reveals a small (3.5-8.4%) but significant mantle contribution. Furthermore the water composition of a deep well (Mesochori) shows important contribution from a hydrothermal component, displaying very high Li and B contents and a clear isotopic shift on a δD-δ18O diagram. Geothermometric estimates of the deep reservoir are in the range 150-180 °C. The uprise of mantle gases is related to the main tectonic structures, which probably allowed also magma intrusion episodes whose heat flow sustain the deep hydrothermal system. Because of the huge input of CO2, the shallow groundwaters of the studied area become acidic and consequently strongly aggressive with respect to the host rocks. At the sampling point many waters display pH values down to 5.5, being generally under the lower limit for drinking waters. Intense rock leaching results in metal release to the solution and enhanced metal fluxes in the aqueous system. As such, magmatic-hydrothermal CO2 input produces a “natural pollution” of the aquifer, where maximum admissible concentrations (MAC) fixed by European Union for drinking waters are exceeded at least for Ni, Mn and Fe in most of the analysed samples. Measured values reach respectively up to 30, 1700 and 55000 µg/l (MACs 20, 50 and 200 µg/l). This natural contamination combines with the pollution due to agricultural practices in the Florina plain, which is responsible for elevated nitrate contents (up to 90 mg/l) often exceeding maximum admissible concentration (50 mg/l). The interaction of natural and anthropogenic contamination of the shallow groundwater resources in the Florina area leads to serious water quality issues

A geochemical traverse along the “Sperchios Basin e Evoikos Gulf” graben (Central Greece): Origin and evolution of the emitted fluids

The studied area is a 130 km long fast spreading graben in Central Greece. Its complex geodynamical setting includes both the presence of a subduction slab at depth responsible for the recent (Quaternary) volcanic activity in the area and the western termination of a tectonic lineament of regional importance (the North-Anatolian fault). A high geothermal gradient is made evident by the presence of many thermal springs with temperatures from 19 to 82 C, that discharge along the normal faults bordering the graben. In the period 2004e2012, 58 gas and 69 water samples were collected and their chemical and isotopic analysis revealed a wide range of compositions. Two main groups of thermal waters can be distinguished on the basis of their chemical composition. The first, represented by dilute waters (E.C. <0.6 mS/cm) of the westernmost sites, is characterised by the presence of CH4-rich and mixed N2eCH4 gases. The second displays higher salinities (E.C. from 12 to 56 mS/cm) due to mixing with a modified marine component. Reservoir temperatures of 150e160 C were estimated with cationic geothermometers at the easternmost sites. Along the graben, from west to east, the gas composition changes from CH4- to CO2-dominated through mixed N2eCH4 and N2eCO2 compositions, while at the same time the He isotopic composi- tion goes from typical crustal values (<0.1 R/RA) up to 0.87 R/RA, showing in the easternmost sites a small (3e11%) but significant mantle input. The d13C values of the CO2-rich samples suggest a mixed origin (mantle and marine carbonates)

GEOCHEMICAL CHARACTERIZATION OF NATURAL GAS MANIFESTATIONS IN GREECE

The Greek region is characterized by intense geodynamic activity with widespread volcanic, geothermal and seismic activity. Its complex geology is reflected in the large variety of chemical and isotopic composition of its gas manifestations. Basing on their chemical composition the gases can be subdivided in three groups, respectively CO2, CH4 or N2-dominated. On oxygen-free basis these three gases make up more than 97% of the total composition. The only exceptions are fumarolic gases of Nisyros that contain substantial amounts of H2S (up to more than 20%) and one sample of Milos that contains 15% of H2. CO2-dominated gases with clear mantle contribution in their He isotopic composition (R/Ra corrected for air contamination ranging from 0.5 to 5.7) are found along the subduction-related south Aegean active volcanic arc and on the Greek mainland close to recent (upper Miocene to Pleistocene) volcanic centers. These areas are generally characterized by active or recent extensive tectonic activity and high geothermal gradients. On the contrary, gases sampled in the more external nappes of the Hellenide orogen have generally a CH4- or N2-rich compositions and helium isotope composition with a dominant crustal contribution (R/Ra corr < 0.2). The chemical and isotopic characteristics of the emitted gas display therefore a clear relationshipwith the different geodynamic sectors of the region. Gas geochemistry of the area contributes to a better definition of the crust-mantle setting of the Hellenic region

Origin and evolution of the fluids emitted along the “Sperchios Basin – Evoikos Gulf” Graben (Central Greece)

The study area is a 130 km long fast spreading graben in Central Greece bordered by active faults. Its complex geodynamical setting includes the presence at depth of a subduction slab responsible for the recent (Quaternary) volcanic activity in the area which possibly represents the northward continuation of the South Aegean active volcanic arc. To the area belongs also the western termination of the North-Anatolian fault a tectonic lineament of regional importance. The high geothermal gradient of the area is evidenced by the presence of many thermal springs with temperatures from 19 to 82 °C, issuing along the normal faults bordering the graben. In the period 2004-2012 more than 60 gas and water samples have been collected and their chemical and isotopic analysis revealed a wide range of compositions. Going from west to east the gas composition changes (Fig. 1) from CH4- to CO2-dominated passing through mixed N2-CH4 and N2-CO2 compositions, while at the same time the He isotopic composition goes from typical crustal values (0.02 R/Ra) up to 0.87 R/Ra (corrected for air contamination), showing in the easternmost sites a small but significant mantle input (up to ~ 10%). Isotopic composition of CH4-C indicates a thermogenic origin for the CH4-rich samples (δ13C from -50 to -37 ‰) and hydrothermal origin for the remaining samples (> -25‰). Positive δ15N values (around +2 ‰) indicate a contribution of crustal derived nitrogen for the N2-rich samples. The most pristine values of δ13C(CO2) refer to the most CO2-rich samples. These values (~ -3 ‰) point to a mixed mantle-marine carbonate source. Lower δ13C values (-10 ÷ -5 ‰) of the other sites can be explained by loss of CO2 due to dissolution processes. Also temperature and salinity of the waters shows differences along the graben increasing from west to east (Fig. 2). Two main groups can be separated on the basis of the total dissolved salts (TDS). The first, represented by dilute waters (TDS < 500 mg/l), is found in the westernmost sites characterised by the presence of CH4-rich and mixed N2-CH4 gases. The remaining waters display higher salinities (TDS from 9 to 35 g/l) due to the mixing with high salinity waters. The water composition can be explained by mixing of two end-members, one with low salinity of meteoric origin and the other with high salinity of marine origin. The mixing can be evidenced in Fig. 2. Low salinity waters show low chloride contents and their light water isotope composition overlaps the field of the cold groundwaters of the area confirming their meteoric origin. High salinity waters are aligned along the mixing line between the cold groundwaters and the seawater confirming the contribution of marine component. Most of the water compositions in the triangular graph of Giggenbach fall in the field of the non equilibrated waters being therefore unsuitable for geothermometric estimations. Only the easternmost sites (Gialtra, Ilion and Edipsos) falling the field of the partially equilibrated waters yield estimated temperatures in the range 150-170 °C. Silica geothermometers confirm these estimations. This study revealed that the complex geodynamic setting of the area is clearly reflected in the wide compositional range of the gases collected in the area that evidence contributions from different end-members (atmosphere, crust, mantle and hydrothermal systems). Water chemistry can be explained mainly from the mixing of a meteoric low-salinity end-member with a high-salinity marine end-member partially modified by hydrothermal water-rock interactions. The highest estimated temperatures in the hydrothermal reservoirs are in the range 150-170 °C

Leachate analyses of volcanic ashes from Stromboli volcano: A proxy for the volcanic gas plume composition?

Many volcanoes show a change in chemical composition of the gas phase prior to periods of eruptive activity. Fine‐grained tephra erupted from active vents and transported through volcanic plumes can adsorb, and therefore rapidly scavenge, volatile elements such as sulfur, halogens, and metal species in the form of soluble salts adhering to ash surfaces. Analysis of such water‐soluble surface materials is a suitable supplement for remote monitoring of volcanic gases at inaccessible volcanoes. In this work, ash samples of the 2004 to 2009 eruptive activity of Stromboli volcano were sampled, leached, and analyzed for major and trace elements. Data analysis and interpretation was focused on determining the relationship between chemical composition of water‐soluble components adhering to volcanic ash and the volcano’s activity state. First results show significant temporal variations in ash leachate compositions, reflecting changes in the eruptive style of the volcano. In particular, we reveal that ash leachates S/F and Mg/Na ratios showed marked increases prior to a large‐scale explosion on 15 March 2007.PublishedD172041.2. TTC - Sorveglianza geochimica delle aree vulcaniche attiveJCR Journalreserve

Application of the moss bag miomonitoring technique in an active volcanic environment (Mt. Etna, Italy)

This paper presents the preliminary results of a biomonitoring study based on the use of moss bags exposed at 24 sites on Etna volcano. Sphagnum mosses were used to study bioaccumulation originating from atmospheric deposition, by measuring the tissue contents of major and a large suite of trace elements. Elements, such as Tl, Bi, As, Se, Cu and Cd, display high concentrations in the exposed samples close to the active vents. This study confirms the effectiveness of the moss bags technique also in active volcanic areas