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Gaseous elemental mercury (Hg 0 g or GEM) and CO 2 are emitted from active hydrothermal systems in volcanic areas mostly through diffuse degassing. Here, data from about 400 simultaneous measurements of soil GEM and CO 2 flux performed within the caldera of Furnas Volcano, São Miguel Island (Azores) are discussed for the first time. This survey aimed at providing a new insight into the origin and magnitude of GEM in the investigated hydrothermal/volcanic environment and its relation with CO 2 release. The distribution of GEM and CO 2 emissions over an area of about 0.04 km 2 are correlated with soil temperature, and measurements have provided total CO 2 and GEM output of 39 t d −1 and 1.8 × 10 −6  t d −1 , respectively. These results are similar to the emission from currently active volcanic/hydrothermal areas elsewhere, as well as from important non-volcanic areas, such as Sulphur Bank Mercury Mine (California, USA) and Idrija Mercury Mine (Slovenia, EU), pointing out the relevance of diffuse degassing processes at Furnas Volcano. Atmospheric spot measurements in the most vigorous fumarole vents of the geothermal field have shown that the fumarolic GEM contribution (9.2 × 10 −7  t d −1 ) represents a minor fraction of the total (fumarolic + diffusive) GEM output (2.7 × 10 −6  t d −1 ) for the study area of this volcano. Basing upon the integration of the hydrothermal CO 2 released and the H 2 O/CO 2 ratio in the fumarolic gas, we have also estimated the thermal energy release associated with diffuse degassing at Furnas Volcano. Our estimates are ∼7.8 MW and 9.8 MW, respectively for Furnas Lake and Furnas Village fumaroles. [ABSTRACT FROM AUTHOR]

Abstract: Mercury is outstanding among the global environmental pollutants of continuing concern. Although degassing of active volcanic areas represents an important natural source of mercury into the atmosphere, still little is known about the amount and behaviour of Hg in volcanic aquifers, especially regarding its chemical speciation. In order to assess the importance of mercury emissions from active volcanoes, thermal waters were sampled in the area surrounding La Solfatara, Pozzuoli bay. This is the most active zone of the Phlegrean Fields complex (coastal area north–west of Naples), with intense hydrothermal activity at present day. Studied groundwaters show total Hg (THg) concentrations range from 56 to 171ng/l and are lower than the 1000ng/l threshold value for human health protection fixed by the World Health Organization (WHO, 1993). We also carefully discriminated the different aqueous species of Hg in the collected water samples. Besides, original data on Hg determination in gaseous manifestations at La Solfatara crater are also reported. We measured volcanogenic mercury concentration and Hg/Stot ratio both in the volcanic plume and in fumarolic condensates in order to better constrain Hg reactivity once emitted into the atmosphere. Data on Hg/Stot reveal that there is no significant difference between Hg volcanic composition at the venting source (fumaroles) and in near-vent diluted volcanic plumes (1.6×10−5 and 1.9×10−5, respectively), suggesting that there is limited Hg chemical processing in volcanic fumarole plumes, at least on the timescales of a few seconds investigated here. Combining the mean fumaroles Hg/CO2 mass ratio of about 1.3×10−8 (molar ratio: 2.1×10−9) with the hydrothermal soil diffuse CO2 degassing of the area, the annual Hg flux from La Solfatara is estimated as 7kg y−1 (0.007t y−1). Current mercury emission from La Solfatara volcano represents a very small contribution to the estimated global volcanic budget for this element, and the estimated Hg flux is considerably lower than that estimated from open-conduit active basaltic volcanoes. [Copyright &y& Elsevier]

Abstract: Quantifying the contribution of volcanism to global mercury (Hg) emissions is important to understand the pathways and the mechanisms of Hg cycling through the Earth''s geochemical reservoirs and to assess its environmental impacts. While previous studies have suggested that degassing volcanoes might contribute importantly to the atmospheric budget of mercury, little is known about the amount and behaviour of Hg in volcanic aquifers. Here we report on detailed investigations of both the content and the speciation of mercury in aquifers of active volcanoes in Italy and Guadeloupe Island (Lesser Antilles). In the studied groundwaters, total Hg (THg) concentrations range from 10 to 500 ng/l and are lower than the 1000 ng/l threshold value for human health protection fixed by the World Health Organization [WHO (1993): WHO Guidelines for Drinking Water Quality- http://www.who.int/water_sanitation_health/GDWQ/index.htlm]. Positive co-variations of (THg) with sulphate indicate that Hg-SO4-rich acid groundwaters receive a direct input of magmatic/hydrothermal gases carrying mercury as Hg0 (gas). Increasing THg in a volcanic aquifer could thus be a sensitive tracer of magmatic gas input prior to an eruption. Since the complex behaviour and toxicity of mercury in waters depend on its chemical speciation, we carefully determined the different aqueous forms of this element in our samples. We find that dissolved elemental Hg0 (aq) and particulate-bound Hg (HgP) widely prevail in volcanic aquifers, in proportions that highlight the efficiency of Hg adsorption onto colloidal particles. Moreover, we observe that dissolved Hg0 aq and Hg(II) forms coexist in comparable amount in most of the waters, in stark contrast to the results of thermodynamic equilibrium modelling. Therefore, chemical equilibrium between dissolved mercury species in volcanic waters is either prevented by natural kinetic effects or not preserved in collected waters due to sampling/storage artefacts. Finally, we provide a first quantitative comparison of the relative intensity of aqueous transport and atmospheric emissions of mercury at Mount Etna, a very active basaltic volcano. [Copyright &y& Elsevier]

There is an urgent need to better constrain the global rates of mercury degassing from natural sources, including active volcanoes. Hitherto, estimates of volcanic fluxes have been limited by the poorly determined speciation of Hg in volcanic emissions. Here, we present a systematic characterisation of mercury partitioning between gaseous (Hg(g)) and particulate (Hg(p)) forms in the volcanic plume of Mount Etna, the largest open-vent passively degassing volcano on Earth. We demonstrate that mercury transport is predominantly in the gas phase, with a mean Hg(p)/Hg(g) ratio of ∼0.01 by mass. We also present the first simultaneous measurement of divalent gaseous mercury () and total gaseous mercury (Hg(g)) in a volcanic plume, which suggests that is the prevalent form of mercury in this context. These data are supported by the results of model simulations, carried out with HSC thermodynamic software. Based on a mean “bulk plume” Hg/SO2 mass ratio of 8.7×10−6, and a contemporaneous volcanic SO2 flux of 0.8Mtyr−1, we estimate an Hg emission rate from Mt. Etna during passive degassing of 5.4tyr−1 (range, 1.1–10tyr−1). This corresponds to ∼0.6% of global volcanic Hg emissions, and about 5% of Hg released from industrial activities in the Mediterranean area. [Copyright &y& Elsevier]

Hydrothermal systems with active surface expressions are important natural source of atmospheric mercury. Here we report on the first simultaneous assessment of gaseous elemental mercury (GEM) and major volatiles (H 2 S and CO 2) fluxes from the fumarolic system of Pisciarelli, currently the most active at the Campi Flegrei caldera (CFc), Naples (Italy). This was achieved via a GPS-synchronized Lumex and MultiGAS survey which extends similar investigations reported elsewhere. GEM concentrations measured in the fumarolic emissions were consistently above background air level close to the degassing area (mean ~ 8 ± 3 ng m−3 on average) and ranged up to 12,000 ng m−3. Our data evidenced pulsed sequences of GEM increases in the fumarole plume, closely matched by temporally consistent increases in CO 2 and H 2 S (r2 = 0.9), supporting the idea that major volatiles, such as CO 2 acts as potential carrier in transporting GEM within the magmatic/hydrothermal systems. The slope of the best fit calculated for the dispersion of our data provides a GEM/CO 2 molar ratio of 1.1 × 10−8 and a GEM/H 2 S of 5 × 10−6, respectively. These ratios are comparable to those reported for both low (~ 100 °C) and high-T (~ 250 °C) fumaroles from non-explosive volcanic/hydrothermal degassing systems elsewhere. We adopted an ad-hoc method that combines video footages and gas measurements to obtain high precision concentration maps of gas emissions used to estimate the total atmospheric GEM, CO 2 and H 2 S flux of about 0.0113, 225059 and 511 t y−1, respectively. The human health risk assessment related to the GEM emissions at Pisciarelli, confirms that, except for the degassing fumarolic area, all the main sites affected by the plume dispersion, always remain well below the safe threshold recommended by the health authorities. • New approach to quantify mercury flux in hydrothermal areas • Hydrothermal degassing acts as a potential source of mercury to the atmosphere. • High correlation between mercury and carbon dioxide • Mercury plume dispersion highlighted by DISGAS code and passive diffusive samplers. • Mercury human health risk assessment at Pisciarelli is below the safe threshold. [ABSTRACT FROM AUTHOR]

Abstract: Mt. Etna is a major natural source of Hg to the Mediterranean region. Total mercury concentrations, [Hg]tot, in Castanea sativa (sweet chestnut) leaves sampled 7–13km from Etna''s vents (during six campaigns in 2005–2011) were determined using atomic absorption spectroscopy. [Hg]tot in C. sativa was greatest on Etna''s SE flank reflecting Hg deposition from the typically overhead volcanic plume. [Hg]tot also showed Hg accumulation over the growing season, increasing with leaf age and recent eruptive activity. [Hg]tot in C. sativa was not controlled by [Hg]tot in soils, which instead was greatest on Etna''s NW flank, and was correlated with the proportion of organic matter in the soil (% Org). An elevated [Hg]tot/% Org ratio in soils on Etna''s SE flank is indicative of increased Hg deposition. This ratio was also found to decrease with local soil pH, suggesting that Hg deposited to the low pH and organic-poor soils on Etna''s SE flank may not be retained but will instead be released to groundwater or re-emitted to the atmosphere. These results show that the deposition of volcanic Hg has clear impacts and confirm that Etna is an important source of Hg to the local environment. [Copyright &y& Elsevier]

Abstract: This study reports on the first quantitative assessment of the geochemical cycling of volcanogenic elements, from their atmospheric release to their deposition back to the ground. Etna’s emissions and atmospheric depositions were characterised for more than 2years, providing data on major and trace element abundance in both volcanic aerosols and bulk depositions. Volcanic aerosols were collected from 2004 to 2007, at the summit vents by conventional filtration techniques. Precipitation was collected, from 2006 to 2007, in five rain gauges, at various altitudes around the summit craters. Analytical results for volcanic aerosols showed that the dominant anions were S, Cl, and F, and that the most abundant metals were K, Ca, Mg, Al, Fe, and Ti (1.5–50μgm−3). Minor and trace element concentrations ranged from about 0.001 to 1μgm−3. From such analysis, we derived an aerosol mass flux ranging from 3000 to 8000ta−1. Most analysed elements had higher concentrations close to the emission vent, confirming the prevailing volcanic contribution to bulk deposition. Calculated deposition rates were integrated over the whole Etna area, to provide a first estimate of the total deposition fluxes for several major and trace elements. These calculated deposition fluxes ranged from 20 to 80ta−1 (Al, Fe, Si) to 0.01–0.1ta−1 (Bi, Cs, Sc, Th, Tl, and U). Comparison between volcanic emissions and atmospheric deposition showed that the amount of trace elements scavenged from the plume in the surrounding of the volcano ranged from 0.1% to 1% for volatile elements such as As, Bi, Cd, Cs, Cu, Tl, and from 1% to 5% for refractory elements such as Al, Ba, Co, Fe, Ti, Th, U, and V. Consequently, more than 90% of volcanogenic trace elements were dispersed further away, and may cause a regional scale impact. Such a large difference between deposition and emission fluxes at Mt. Etna pointed to relatively high stability and long residence time of aerosols in the plume. [Copyright &y& Elsevier]

Abstract: A major uncertainty regarding the environmental impacts of volcanic Hg is the extent to which Hg is deposited locally or transported globally. An important control on dispersion and deposition is the oxidation state of Hg compounds: Hg(0) is an inert, insoluble gas, while Hg(II) occurs as reactive gases or in particles, which deposit rapidly and proximally, near the volcanic vent. Using a new high temperature thermodynamic model, we show that although Hg in Etna''s magmatic gases is almost entirely Hg(0) (i.e., gaseous elemental mercury), significant quantities of Hg(II) are likely formed at Etna''s vents as gaseous HgCl2, when magmatic gases are cooled and oxidised by atmospheric gases. These results contrast with an earlier model study and allow us to explain recent measurements of Hg speciation at the crater rim of Etna without invoking rapid (<1min) low temperature oxidation processes. We further model Hg speciation for a series of additional magmatic gas compositions. Compared to Etna, Hg(II) production (i.e., Hg(II)/Hgtot) is enhanced in more HCl-rich magmatic gases, but is independent of the Hg, HBr and HI content of the magmatic gases. Hg(II) production is not strongly influenced by the initial oxidation state of magmatic gases above NNO, although production is hindered in more reduced magmatic gases. The model and results are widely applicable to other open-vent volcanoes and may be used to improve the accuracy of chemical kinetic models for low temperature Hg speciation in volcanic plumes. [Copyright &y& Elsevier]

The first attempt to systematically investigate the atmospheric mercury (Hg) in the MBL of the Augusta basin (SE Sicily, Italy) has been undertaken. In the past the basin was the receptor for Hg from an intense industrial activity which contaminated the bottom sediments of the Bay, making this area a potential source of pollution for the surrounding Mediterranean. Three oceanographic cruises have been thus performed in the basin during the winter and summer 2011/2012, where we estimated averaged Hgatm concentrations of about 1.5±0.4 (range 0.9-3.1) and 2.1±0.98 (range 1.1-3.1) ng m(-3) for the two seasons, respectively. These data are somewhat higher than the background Hg atm value measured over the land (range 1.1±0.3 ng m(-3)) at downtown Augusta, while are similar to those detected in other polluted regions elsewhere. Hg evasion fluxes estimated at the sea/air interface over the Bay range from 3.6±0.3 (unpolluted site) to 72±0.1 (polluted site of the basin) ng m(-2) h(-1). By extending these measurements to the entire area of the Augusta basin (~23.5 km(2)), we calculated a total sea-air Hg evasion flux of about 9.7±0.1 g d(-1) (~0.004 tyr(-1)), accounting for ~0.0002% of the global Hg oceanic evasion (2000 tyr(-1)). The new proposed data set offers a unique and original study on the potential outflow of Hg from the sea-air interface at the basin, and it represents an important step for a better comprehension of the processes occurring in the marine biogeochemical cycle of this element., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: Palladium is increasingly used in industry, jewelry, and dentistry and is becoming more common since the European directive restricting the use of nickel in all products placed in direct and prolonged contact with the skin., Objective: The role of palladium sensitization is still unclear, and the aim of our study is to evaluate the trend of sensitization in a contact dermatitis clinic population during a 10-year period., Methods: We report our experience with 4,446 patients (3,077 female, 1,369 male; mean age, 40.1 +/-13.7 years) with suspected contact dermatitis patch-tested during the period of 1991 to 2000., Results: A positive patch-test result to palladium chloride 1% was indicated in 236 patients (5.3%), with a higher percentage in females (6.7%) than in males (2.3%), and the sensitization to this metal has increased over the specified period, to a maximum in the year 2000 (9.7%). In the majority of cases, subjects were polysensitized (92.8%), but 7.2% of subjects were patch-test positive only to palladium. Of palladium-sensitized patients, 40.5% complained of hand dermatitis, 47.4% complained of body dermatitis, and 1.7% complained of burning mouth syndrome. Palladium sensitization is significantly related to female sex (OR = 3.08; 95% CI, 2.07-4.61) and to sensitization to other metals, with a maximum for nickel sulfate (OR = 32.9; 95% CI, 21.3-51.5)., Conclusion: Sensitization to palladium is increasing by the year, reaching high values, but its role in reducing sensitization and symptoms is still unclear because of the frequent cosensitization with nickel and the low number of monosensitized patients with relevant sensitizations. We need to follow palladium sensitization in future years to verify an increase of sensitization due to the increasing use of this metal.