Preliminary study on geogenic degassing through the big karstic aquifers of Greece

Non-volcanic degassing contributes to the C-cycle by providing on a global scale a significant amount of CO2 emitted through diffuse earth degassing processes (Kerrick et al 1995). Due to the elevated solubility of the CO2 in water, in the areas where high CO2 fluxes directly affect regional aquifers, most of it can be dissolved, transported and released by groundwaters. Therefore, quantification of this contribution to the atmosphere has a substantial implication for modeling the global carbon cycle. According to Chiodini et al. (2000), total dissolved inorganic carbon (TDIC) concentrations and δ13CTDIC values of groundwaters are useful tools to both quantify the geogenic degassing and distinguish the different carbon sources. This approach was proved to be valid for central Italy and can possibly work for continental Greece; due to similar geodynamic history. Greece is considered one of the most geodynamically active regions and is characterized by intense geogenic degassing. The main source of degassing in the Hellenic area is concentrated on hydrothermal and volcanic environments (Daskalopoulou et al., 2019), however, the impact of geogenic CO2 released by tectonically active areas shouldn’t be disregarded. Aim of this work is to quantify the CO2 degassing through aquifers hosted in the carbonate successions in the Hellenic region. 95 karst, thermal and cold waters were collected in the northern and central part of Greece with some of which being characterized by bubbling of CO2-rich gases. Results show that karst waters have a typical Ca-HCO3 composition. Thermal and cold waters show two different compositions: some samples are characterized by Ca-HCO3 composition suggesting the presence of a carbonate basement, whilst others have a prevailing Na-HCO3 composition. On the basis of TDIC concentrations and δ13CTDIC values, the springs are divided into two groups. The first group includes karst waters and some of thermal waters and is characterized by low TDIC concentrations and negative δ13CTDIC values. This group shows no evidence of deep CO2 contributions, whereas the carbon of these waters derives from dissolution of carbonate minerals by organic derived CO2. Remaining samples belong to the second group and present intermediate to high TDIC concentrations and δ13CTDIC values, indicating a possible input of inorganic CO2. Some of these springs are characterized by gas bubbling at discharge, suggesting an extensive degassing

Estimation of CO2 release from thermal springs to the atmosphere

Introduction Geodynamically active regions have long been recognized as areas of anomalous Earth degassing [Irwin and Barnes, 1980]. Areas found at plate boundaries are characterized by seismic, volcanic and geothermal activity as well as ore deposition. These processes are enhanced by the circulation of hydrothermal fluids in the crust, which transport volatiles from the deep crust or mantle to the surface [King, 1986]. Kerrick and Caldera, [1998], were the first to indicate the significant contribution of the CO2 degassing by extensional tectonic and hydrothermal activity in metamorphic belts during the Phanerozoic. Moreover, further studies concerning gas emissions from diffuse degassing tectonic structures on various geological regimes suggested in their majority elevated CO2 concentrations [Klusman, 1993]. In fact, it is worth noting that the estimated global hydrothermal CO2 flux from subaerial geothermal environments can be comparable to that of direct volcanic discharges [Kerrick et al., 1995; Seward and Kerrick, 1996]. Study Area The back-arc geothermal fields of Greece include, among others, the Tertiary sedimentary basins of both Sperchios Basin and north Euboea, which are located in central Greece. Their tectonic activity contributes in crust thinning [Papadakis at al., 2016 and references therein] and elevated heat flow values [Fytikas and Kolios, 1979]. These geothermal anomalies due to the tectonic activity and the geological and volcanic regime are expressed as hot springs (Ypatis, Psoroneria, Thermopyles and Kamena Vourla in Sperchios Basin and Edipsos and Ilion in north Euboea). Tectonics of central Greece seems to be of particular interest as major fault structures are found in the area. Sperchios Basin was formed through the activity of WNW-ESE trending faults [Georgalas and Papakis, 1966; Marinos et al., 1973], whilst the Sperchios tectonic graben itself is considered to be the extension of the North Anatolia strike-slip fault. Moreover, in the north Euboean Gulf, the major fault structures are those of the Atalanti Fault Zone (AFZ) that consist of several segments of normal faults, trending about NW-SE [Pavlides et al., 2004]. Materials and Methods Six groups of springs (Ypatis, Psoroneria, Thermopyles, Kamena Vourla, Edipsos and Ilion) were investigated in this study. Bubbling gases were sampled using an inverted funnel positioned above the bubbles and stored in glass flasks equipped with two stopcocks until analysis. Samples for dissolved gas analyses were collected in glass vials and were sealed underwater. In the laboratory, the concentrations of He, H2, H2S, O2, N2, CO2 and CH4, on the samples were analysed by an Agilent 7890B gas chromatograph with Ar as carrier. The total CO2 emitted through bubbling was measured at 6 different pools (Psoroneria, Psoroneria 2,Thermopyles, Leonidas, Kamena Vourla and Ilion), whereas at other springs (Koniavitis-Sperchios Basin, Edipsos-Damaria and Edipsos-Thermopotamos) an estimation of the release was made by visual inspection. The CO2 fluxes were measured using the floating chamber method [Mazot and Bernard, 2015] that was equipped with a portable fluxmeter (WEST Systems, Italy) based on the accumulation chamber method as suggested by Chiodini et al., [1998]. The flux data were processed with both the Graphical Statistical Approach (GSA) and the Stochastic Simulation Approach (SSA), with the latter being based on the algorithm of sequential Gaussian simulation [Deutsch and Journal 1998; Cardellini et al., 2003]. Zonal Statistics on the final CO2 flux maps was obtained using the ArcMap 10.3 (ESRI) Spatial Analyst tool and were used to estimate the total CO2 output to the atmosphere. Results and Conclusions Carbon dioxide is the prevailing gas species for the great majority of the under investigation sites, with only gases collected in the area of Kamena Vourla (Kamena Vourla and Koniavitis) being rich in N2. The total bubbling CO2 emission from the pools to the atmosphere ranged from 314 to 44,800 g/m2/day. At sites with greater surfaces, the CO2 release was estimated after performing direct measurements (28-Thermopyles, 74-Psoroneria) with the most elevated values being found in the areas of Thermopyles and Psoroneria (1 and 2 t/d, respectively) (Tab. 1); the maps were drawn following the SSA (Figure 1). The outgoing channels of the springs showed an elevated flow (> 250 l/s) of gas-charged water (> 15 mmol/l of dissolved CO2). Even though no bubbling was visible along the stream, the dissolved CO2 content sampled at different distances from springs of Psoroneria and Thermopyles, decreased up to an order of magnitude after few hundreds of metres, indicating an evident and intense, although not visible, CO2 degassing versus the atmosphere. Physico-chemical parameters (temperature and pH) along the outlet channels were also measured at the same sampling points showing correlations (negative in terms of temperature; T decreased from 33.1 to 30.3 and 40.8 to 39 °C, respectively and positive in terms of pH; pH increased from 6.11 to 7.05 and 6.05 to 7.70, respectively) with the distance. The CO2 output of the outgoing channels to the atmosphere was quantified considering thedifference between the initial and the final content of the dissolved CO2 as well as the water flow, obtaining values of > 10 t/d for Thermopyles and ~9 t/d for Psoroneria. Estimations were also made at Ypatis, Kamena Vourla, Koniavitis and Edipsos, where the mean values reached 1 t/d of CO2 for each spring. The obtained CO2 released from the bubbling pools to the atmosphere was directly compared with the one estimated from the outgoing channels (Tab. 1). The degassing along the outflow channel was almost always higher than the corresponding bubbling pool, sometimes even an order of magnitude, suggesting that most of the degassing is “hidden”. For each site the amount of CO2 released versus the atmosphere was calculated as (Figure 2): ΦtotCO2 = Φpool + Φstream The total CO2 released to the atmosphere as estimated for the study area is at ~ 30 t/d, with the major contribution deriving from the degassing along the outflow channels of the thermal springs. Such output is comparable and sometimes higher than that of each single active volcanic system along the South Aegean Volcanic Arc (15 - 38 t/d) and highlights the importance of “hidden” degassing along CO2 - oversaturated streams

Microbial impact on the isotope composition of methane in both thermal and hyperalkaline waters of central Greece

Introduction The different origins of methane can be subdivided in biogenic (either directly produced by microbial activity or deriving by decay of organic matter at T > 150\ub0C) and abiogenic (from pure inorganic reactions). Among the latter, one of the most debated origins comes from serpentinization processes of ultramafic rocks in ophiolitic sequences at low temperatures (T < 80 \ub0C). Moreover, further secondary processes (diffusion, inorganic or microbial oxidation, etc.) may also contribute and thus mask the original chemical and/or isotope composition. Primary and secondary processes acting on CH4 can be recognised mainly through its isotope (d13C and d2H) composition and the ratio between CH4 and C2+C3 light hydrocarbons [Bernard et al. 1978; Schoell 1980]. Microorganisms may be involved in the methane cycle not only as active producers but also as consumers. Methane oxidizing bacteria (or methanotrophs) are microorganisms with the ability to use methane as the only source of carbon for energy and biomass production. Methanotrophs are ubiquitous and play an important role in the global carbon cycle, acting as a natural filter between the subsoil and the atmosphere. They were isolated from several environments such as soils, wetlands, freshwater, marine sediments, water columns, groundwater, rice paddies, and peat bogs [Murrell and Jetten, 2009]. Some species were adapted also at extreme environments characterized by high temperature (up to 81.6 \ub0C), extremely low or high pHs (1.5-11) or even anaerobic conditions. Due to the fact that methanotrophs metabolize preferentially light isotopes, biologic methane oxidation brings sometimes to extremely positive d13C and d2H values [Cadieux et al., 2016]. The Greek territory belongs to the geodynamically active Alpine-Himalayan orogenic belt. As such, it shows intense seismic activity, active volcanic systems and areas of enhanced geothermal fluxes. One of these areas is the Sperchios Basin and the northern part of Euboea Island in central Greece, where thermal manifestations are widespread [D\u2019Alessandro et al., 2014]. The complex geology of Greece includes also two important parallel running ophiolitic belts, with the Othrys Massif (central Greece) belonging to the westernmost of them. In and around this wide ophiolite outcrop, some cold hyperalkaline and some hypothermal (T < 30\ub0C) alkaline waters are present. In the present paper we discuss data about chemistry and methane isotope composition of bubbling or dissolved gases in both thermal springs and hyperalkaline springs of Central Greece. Sampling and Analytical Methods Free bubbling gas samples were taken using an inverted funnel. All free gas samples were stored in Pyrex bottles with two vacuum stopcocks. Samples for dissolved gas analyses were collected in glass vials sealed underwater. In the laboratory, the chemical analyses were carried out by gaschromatography (Agilent 7890B GC System) using Ar as the carrier gas. Dissolved gases were extracted after equilibrium was reached at constant temperature with a host-gas (high-purity argon) injected in the sample bottle. The measurement precision was better than \ub15% for common gases and \ub110% for trace gases such as the alkanes. The chemical composition of the dissolved gas phase was obtained from the gas-chromatographic analyses taking into account the solubility coefficients (Bunsen coefficient \u201c\u3b2\u201d, ccgas/mlwater STP) of each gas specie, the volume of gas extracted and the volume of the water sample (details in Capasso and Inguaggiato, [1998] and Liotta and Martelli, [2012]). Starting from the total amount of dissolved gases (ccSTP/L) we calculated the relative abundances for every single gas species in equilibrium with the dissolved gas phase and expressed the analytical results in \u3bcmol/mol of gas at atmospheric pressure, allowing the comparison of dissolved gases with free gases. Carbon and hydrogen isotope compositions of CH4 were measured using a Thermo TRACE GC and a Thermo GC/C III interfaced to a Delta Plus XP gas source mass spectrometer. 13C/12C ratios are reported here as d13C values (\ub10.1 \u2030) with respect to the V-PDB standard. 1H/2H ratios are reported here as d2H values (\ub12 \u2030) with respect to the V-SMOW standard. The oxygen and hydrogen isotopic compositions of water were analysed on unfiltered samples with the use of Analytical Precision AP 2003 and FinniganMAT Delta Plus IRMS devices, respectively. The isotope ratios are expressed as the deviation per mil (\u3b4\u2030) from the reference V-SMOW. The uncertainties (\ub11\u2030 were \ub10.1% for \u3b418O and \ub11% for \u3b42H. Results Five thermal springs, with temperatures from 33 to 80\ub0C, were sampled in the study area. All show elevated fluxes of bubbling gases whose prevailing species are either CO2 or N2. Methane concentrations range from 27 to 4000 \u3bcmol/mol, whilst the isotope composition of CH4 covers a wide range with d13C values ranging from -21.7 to +16.9\u2030 and d2H values ranging from -124 to +370\u2030. Seven alkaline hypothermal waters were collected in five areas (Amplas, Platystomo, Kaitsa, Smokovo and Soulanta) while 10 hyperalkaline waters in two areas (Archani and Ekkara); all samples were collected from different springs and wells and some of the sites presented bubbling. All samples present low concentrations of H2 (from <2 to 2500 \u3bcmol/mol), CO2 (up to 26,000 but generally below 1000 \u3bcmol/mol) and O2 (up to 16,000 but generally below 3000 \u3bcmol/mol). Gases in alkaline waters (pH <10) are in their majority dominated by CH4 (from 128,000 to 915,000 \u3bcmol/mol). Hyperalkaline (pH > 11) waters are N2 dominated (from 727,000 to 977,000 \u3bcmol/mol) and have CH4 concentrations from 11,500 to 279,000 \u3bcmol/mol. Also all these samples display a wide range of isotope compositions of CH4 (d13C from -74.5 to -14.5 \u2030 and d2H from -343 to -62 \u2030). Discussion Thermal springs Methane in most of the bubbling gases found in the thermal waters of Greece display a small range in isotope composition close to -21\u2030 for carbon and to -130\u2030 for hydrogen [Daskalopoulou et al., 2018] and plot in the middle of the field of volcanic and geothermal systems (Figure 1). In the study area, only the hottest (Edipsos) of the thermal manifestations displays similar values. All the remaining samples fit a methane oxidation trend reaching extremely positive values (Figure 1). If we consider the lowest values as the deep hydrothermal marker the obtained \u394H/\u394C values range between 5 and 13 which are close to those typical of microbially driven oxidation [Coleman et al., 1981]. Although the outlet temperature of the hottest manifestations is at the upper limit for methanotrophic microrganisms [Sharp et al., 2014], we can hypothesize that environmental conditions are not favourable for their survival at this site. On the contrary, methanotrophs can thrive in the sites characterized by lower temperatures (33-65 \ub0C), strongly consuming methane. The most positive values were measured at Psoroneria and indicate a very high consumption fraction. Considering again the values of Edipsos as the deep hydrothermal marker, a Rayleigh fractionation modelling in a closed system and kinetic fractionation factors for microbial oxidation [Coleman et al., 1981] we estimate a consumption of more than the 75% of the initial CH4. Alkaline and hyperalkaline waters Alkaline waters present mostly isotope values for CH4 compatible with a biogenic origin (d13C from - 62.0 to -37.5 \u2030 and d2H from -247 to -154 \u2030). Only the sample of Kaitsa falls above the biogenic field, indicating possible fractionation due to CH4 oxidation (Figure 2). Most of the hyperalkaline waters have CH4 isotope values compatible with an abiogenic origin through serpentinization processes (Figure 2). But some of the CH4 collected in the hyperalkaline waters show values falling in the biogenic field, with at points, very negative d13C values (< -70\u2030). Methanogens were found also in other hyperalkaline waters taking advantage of the presence of sometimes very high hydrogen concentrations [Woycheese et al., 2015; Miller et al., 2018]. Also methanotrophs were rarely found in hyperalkaline waters [Woycheese et al., 2015; Miller et al., 2018] and their presence may justify the most positive values found in the study area (Figure 2)

Carbon degassing through karst hydrosystems of Greece

Estimation of CO2 degassing from active tectonic structures and regional hydrothermal systems is essential for the quantification of presentday Earth degassing [Frondini et al., 2019 and references therein]. Due to the high solubility of CO2 in water, great amounts of deep inorganic carbon can be dissolved, transported, and released from regional aquifers. By applying a massbalance approach [Chiodini et al., 2000], different sources of the dissolved CO2 can be discriminated. The main source of degassing in Greece is concentrated in hydrothermal and volcanic areas. However, deep CO2 from active tectonic areas has not yet been quantified. A key point of this research is to investigate the possible deep CO2 degassing through the big karst aquifers of Greece. From May 2016, 156 karst springs were sampled along the greatest part of the Hellenic region. To discriminate the different carbon sources, we analyzed the chemical and isotopic composition of total dissolved inorganic carbon (TDIC). Results yield TDIC values from 1.89 to 21.7 mmol/l and δ13CTDIC from 16.61 to 0.91 ‰. On this basis, karst springs are clustered into two groups: (a) low TDIC and δ13CTDIC values and (b) intermediate TDIC and δ13CTDIC values. The carbon of the first group derives from organic source and dissolution of carbonates; whilst the second group shows a possible carbon input from deep source. This geogenic carbon is mostly related to high heat flux areas, often near active or recent (Quaternary) volcanic systems

Duvalo (North Macedonia): A "volcano" without volcanic activity

T he Duvalo locality is located in the SW of the Republic of North Macedonia, in the Ohrid region, near the village of Kosel. It is an area of strong soil degassing, called “volcano” by the local people despite volcanic activity has never been documented in the recent geologic history of the area [1]. A large area (thousands of sqm) shows signs of strong alteration and is devoid of vegetation. Until the 19thcentury sulphur was mined from this area [1]. In August 2019, a campaign of soil CO2 flux measurements and soil gas sampling was made. Duvalo is sometimes referred to as an active geothermal feature but no signs of enhanced geothermal gradient were found and the soil temperatures at 50 cm depth in this campaign were always within the range of local mean air temperatures. Soil CO2 flux values ranged from 1.3 to 59,000 g/m2/d and can be modelled with the overlapping of 3 or 4 flux populations. A possible biological background is estimated in 6.8±1.8 g/m2/d while the other populations are characterized by an anomalous average flux ranging from 180 to 33,000 g/m2/d. The CO2 total emission, estimated both with a statistical and geostatistical approach, provided similar values in the order of 50 t/d. This has to be considered as a minimum value because only areas with evident signs of alteration have been investigated. Nevertheless, the estimated output is quite high for an area unrelated with recent volcanism or geothermal activity. The chemical composition of soil gases shows: CO2 (96.6%), N2 (1.8%), H2S (0.6%) and CH4 (0.3%) as the main gases. The present composition is almost indistinguishable from previous analyses made in 1957 and 1977 [1] pointing to a stability of the system in last decades. The isotope compositions indicate for CO2 (δ13C -0.2 ‰) a pure carbonate rock origin, for CH4 (δ13C -34.4 ‰ and δ2H -166 ‰) a thermogenic origin and for He (R/RA 0.10) a pure crustal origin. The H2S released at Duvalo may be produced by either microbial or thermochemical sulphate reduction favoured by hydrocarbons whose presence can be inferred by the uprise of thermogenic methane. Partial oxidation of H2S during its upflow, producing sulphuric acid, may be responsible of the production of abundant CO2 through dissolution of carbonate rocks. Similar processes have been evidenced also in other parts of North Macedonia [2]. These gases rise up through the N–S trending normal faults bordering the seismically active Ohrid basin graben [3] being released to the atmosphere through the soils of Duvalo “volcano”

PRGdb 2.0 : towards a community-based database model for the analysis of R-genes in plants

The Plant Resistance Genes database (PRGdb; http://prgdb.org) is a comprehensive resource on resistance genes (R-genes), a major class of genes in plant genomes that convey disease resistance against pathogens. Initiated in 2009, the database has grown more than 6-fold to recently include annotation derived from recent plant genome sequencing projects. Release 2.0 currently hosts useful biological information on a set of 112 known and 104 310 putative R-genes present in 233 plant species and conferring resistance to 122 different pathogens. Moreover, the website has been completely redesigned with the implementation of Semantic MediaWiki technologies, which makes our repository freely accessed and easily edited by any scientists. To this purpose, we encourage plant biologist experts to join our annotation effort and share their knowledge on resistance-gene biology with the rest of the scientific community

Preliminary geochemical characterization of gas manifestations in North Macedonia

L ike most of the Balkan Peninsula, North Macedonia is a geodynamically active area. As such it has many hydrothermal features and gas manifestations. Until now, no systematic study about the geochemical characterization of the geogenic gases was made before in this country. In August 2019, 24 gas samples were collected in the study area. All, except one collected at Duvalo (soil gas), are gases bubbling or dissolved in thermomineral waters (temperatures from 12 to 66 \ub0C). They were analysed in the laboratory for their chemical (He, Ne, Ar, O2 , N2 , H2 , H2S, CH4 and CO2) and isotopic composition (\u3b413C-CO2, \u3b413C-CH4, \u3b42H-CH4 and R/RA). Most of the gases have CO2 as the main component (400-998,000 ppm) while the remaining are enriched in N2 (1300-950,000 ppm). Helium ranges from 0.3 to 2560 ppm while CH4 from 1.6 to 20,200 ppm. R/RA and 4He/20Ne ratios indicate a generally low atmospheric contamination, a prevailing crustal contribution and mantle contributions between 1 and 20% considering a MORB endmember. The highest mantle contributions are found in the SE part of the country very close to the sites that show the highest R/RA values in continental Greece [1]. This area is characterised by extensional tectonics and Plio- Pleistocene volcanism. A quite high mantle contribution (about 15%) is also found in two manifestations in the NW part of the country along a main normal fault system. With the exception of the sample of Smokvica, which has very low CO2 (1400 ppm) and \u3b413C-CO2 (-15.7 \u2030 V-PDB), all free gases show a relatively narrow range in \u3b413C-CO2 values (-4.6 to +1.0 \u2030 V-PDB) indicating the mixing between a mantle and a carbonate rock source. The isotope composition allows us to assign the CH4 origin to three sources. The largest group can be attributed to a hydrothermal origin (\u3b413C-CH4 around -20 \u2030 V-PDB and \u3b42H-CH4 around -100\u2030). Three samples collected in the SW part of the country have a thermogenic origin (\u3b413C-CH4 around -35 \u2030 V-PDB and \u3b42H-CH4 around -160\u2030 V-SMOW). Finally, one sample (Smokvica) with the highest values (\u3b413C-CH4 -7.2 \u2030 V-PDB and \u3b42H-CH4 -80\u2030 V-SMOW) may be attributed to abiotic processes in a continental serpentinization environment or to methane oxidation

In vivo parasitological measures of artemisinin susceptibility

Parasite clearance data from 18,699 patients with falciparum malaria treated with an artemisinin derivative in areas of low (n=14,539), moderate (n=2077), and high (n=2083) levels of malaria transmission across the world were analyzed to determine the factors that affect clearance rates and identify a simple in vivo screening measure for artemisinin resistance. The main factor affecting parasite clearance time was parasite density on admission. Clearance rates were faster in high-transmission settings and with more effective partner drugs in artemisinin-based combination treatments (ACTs). The result of the malaria blood smear on day 3 (72 h) was a good predictor of subsequent treatment failure and provides a simple screening measure for artemisinin resistance. Artemisinin resistance is highly unlikely if the proportion of patients with parasite densities of <100,000 parasites/microL given the currently recommended 3-day ACT who have a positive smear result on day 3 is <3%; that is, for n patients the observed number with a positive smear result on day 3 does not exceed (n + 60)/24

Degassing and Cycling of Mercury at Nisyros Volcano (Greece)

Nisyros Island (Greece) is an active volcano hosting a high-enthalpy geothermal system. During June 2013, an extensive survey on Hg concentrations in different matrices (fumarolic fluids, atmosphere, soils and plants) was carried out at Lakki Plain, an intra-caldera area affected by widespread soil and fumarolic degassing. Concentrations of gaseous elemental mercury (GEM), H2S and CO2, were simultaneously measured in both the fumarolic emissions and the atmosphere around them. At the same time, 130 samples of top soils and 31 samples of plants (Cistus Creticus and Salvifolius and Erica Arborea and Manipuliflora) were collected for Hg analysis. Mercury concentrations in fumarolic gases ranged from 10,500 to 46,300 ng/m3, while Hg concentrations in the air ranged from high background values in the Lakki Plain caldera (10-36 ng/m3) up to 7100 ng/m3 in the fumarolic areas. Outside the caldera, the concentrations were relatively low (2-5 ng/m3). The positive correlation with both CO2 and H2S in air highlighted the importance of hydrothermal gases as carrier for GEM. On the other hand, soil Hg concentrations (0.023-13.7 µg/g) showed no significant correlations with CO2 and H2S in the soil gases, whereas it showed a positive correlation with total S content and an inverse one with the soil-pH, evidencing the complexity of the processes involving Hg carried by hydrothermal gases while passing through the soil. Total Hg concentrations in plant leaves (0.010-0.112 μg/g) had no direct correlation with soil Hg, with Cistus leaves containing higher values of Hg respect to Erica. Even though GEM concentrations in air within the caldera are sometimes orders of magnitude above the global background, they should not be considered dangerous to human health. Values exceeding the WHO guideline value of 1000 ng/m3 are very rare (<0.1%) and only found very close to the main fumarolic vents, where the access to tourists is prohibited.PublishedID 47835146A. Geochimica per l'ambiente e geologia medicaJCR Journa

Six-month psychophysical evaluation of olfactory dysfunction in patients with COVID-19

This study prospectively assessed the six-month prevalence of self-reported and psychophysically measured olfactory dysfunction in subjects with mild-to-moderate COVID-19. Self-reported smell or taste impairment was prospectively evaluated by SNOT-22 at diagnosis, 4-week, 8-week, and 6-month. At 6 months from the diagnosis, psychophysical evaluation of olfactory function was also performed using the 34-item culturally adapted University of Pennsylvania Smell Identification Test (CA-UPSIT). 145 completed both the 6-month subjective and psychophysical olfactory evaluation. According to CA-UPSIT, 87 subjects (60.0%) exhibited some smell dysfunction, with 10 patients being anosmic (6.9%) and 7 being severely microsmic (4.8%). At the time CA-UPSIT was administered, a weak correlation was observed between the self-reported alteration of sense of smell or taste and olfactory test scores (Spearman's r=-0.26). Among 112 patients who self-reported normal sense of smell at last follow-up, CA-UPSIT revealed normal smell in 46 (41.1%), mild microsmia in 46 (41.1%), moderate microsmia in 11 (9.8%), severe microsmia in 3 (2.3%), and anosmia in 6 (5.4%) patients; however, of those patients self-reporting normal smell but who were found to have hypofunction on testing, 62 out of 66 had self-reported reduction in sense of smell or taste at an earlier time point. Despite most patients report a subjectively normal sense of smell, we observed a high percentage of persistent smell dysfunction at 6 months from the diagnosis of SARS-CoV-2 infection, with 11.7% of patients being anosmic or severely microsmic. These data highlight a significant long-term rate of smell alteration in patients with previous SARS-COV-2 infection