scholarly journals Degassing and Cycling of Mercury at Nisyros Volcano (Greece)

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
A. L. Gagliano ◽  
S. Calabrese ◽  
K. Daskalopoulou ◽  
J. Cabassi ◽  
F. Capecchiacci ◽  
...  
Keyword(s):  
Elemental Mercury ◽  
Active Volcano ◽  
Geothermal System ◽  
High Background ◽  
Positive Correlation ◽  
Gaseous Elemental Mercury ◽  
High Enthalpy ◽  
Guideline Value ◽  
Global Background ◽  
Soil Hg

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 the Lakki Plain, an intracaldera area affected by widespread soil and fumarolic degassing. Concentrations of gaseous elemental mercury (GEM), together with 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 with respect to Erica. Even though GEM concentrations in the 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.

scholarly journals Diffuse gases in soil of Araro-Simirao geothermal system, Michoacan, Mexico

2021 ◽  
Vol 48 (3) ◽  
Author(s):  
Isabel Pérez-Martínez ◽  
Ruth Esther Villanueva-Estrada ◽  
Augusto Antonio Rodríguez-Díaz ◽  
Carles Canet ◽  
Rocío García ◽  
...  
Keyword(s):  
Boron Content ◽  
Volcanic Belt ◽  
Co2 Flux ◽  
Elemental Mercury ◽  
Geothermal System ◽  
Gas Emission ◽  
Gaseous Elemental Mercury ◽  
Sampling Campaign ◽  
High Boron ◽  
South Zone

The Araró-Simirao geothermal system is in the southeast part of the Cuitzeo Lake depression. Physiographically, it is located in the eastern portion of the central part of the TransMexican Volcanic Belt province (TMVB). It is a convective hydrothermal system of dominant liquid, with chlorinated sodium waters and high boron content. The principal gas emitted by the thermal springs is CO2 and, in lower concentrations, H2S, H2 and noble gases (He, Ne, Ar). The aim of this study was to delimit fluid ascent areas in the geothermal system by determining the relationships between diffuse gas emission concentrations in soils and the greatest permeability plausible zones (principal faults). Three sampling campaigns were carried out during 2018 (August and November) and 2019 (May), in which diffuse gas emission measurements (CO2, Rn and mercury vapors) across the soils and soil temperature measurements were carried out. For a sampling campaign, the CO2 flux ranged between 4.38 and 94.61 g m-2 d-1 and the gaseous elemental mercury (GEM) concentration ranged between 0.5 and 365 ng/m3. For the other sampling campaign, the CO2 flux ranged between 0.8 and 1,421 g m-2 d-1 and the GEM values ranged between 0.49 and 2,914ng/m3. In the last sampling campaign the222Rn and 220Rn were also measured, and these values oscillated between 1,060 and 124,100 Bq/m3 and from 0 to 7,511 Bq7m3, respectively. Several anomalous zones of CO2 fluxes, GEM and 222Rn concentrations were found, which match the greatest permeability zones (faults and lineaments). The zone with the highest values in these three parameters is located in the so-called «mud pool», at the crossing of the Araró-Simirao fault with a lineament NW-SE (south zone), which is associated with the upflow zone of the system. Other anomalous zones were also located in the fracture and/or lineaments zones in the central and north parts of the system, which are associated with the outflow zone. According to the data obtained, CO2 could be functioning as a carrier of Hg and 222Rn in the area of vertical rise of gases and, in the outflow zone this gas may be found dissolved in the groundwater.

scholarly journals NATURAL DEGASSING OF CARBON DIOXIDE AND HYDROGEN SULPHIDE AND ITS ENVIRONMENTAL IMPACT AT MILOS ISLAND, GREECE

2017 ◽  
Vol 43 (5) ◽  
pp. 2361 ◽  
Author(s):  
G.K. Kyriakopoulos
Keyword(s):  
Active Volcano ◽  
Geothermal System ◽  
Fumarolic Activity ◽  
Atmospheric Gases ◽  
Volcanic Gas ◽  
Aegean Region ◽  
High Enthalpy ◽  
North East ◽  
Mantle Component ◽  
Micro Plates

The Aegean region represents an active convergent zone, where continental micro-plates exhibit a complex interaction between the African and the Eurasian plates. The calc-alkaline volcanic activity of the Southern Aegean region developed in various volcanic centers from Soussaki to Nisyros through Methana-Poros, Milos and Santorini. Milos Island has been an active volcano till the middle of Quaternary and is at present characterized by a high enthalpy geothermal system. The volcanism started 3.5 Ma ago and still continues up today in the form of post-volcanic manifestations. Most quiescent volcanoes released large amounts of CO2 and H2S through fumarolic activity and soil diffuse degassing. Numerous small fumaroles occur in various places, mainly at Kalamos and Adamas volcanic areas. Also along the southern coast of the island there are volcanic gas manifestations in the sea. Gases were sampled from fumaroles at Kalamos area as well as from north east part of Adamas village. Furthermore many soil gases were sampled at 50 cm depth and analyzed for their chemical composition. Apart from atmospheric gases (N2 and O2), which sometimes contaminate the samples, the main gas phase is CO2. Sometimes also H2S, CH4 and H2 are present in high amounts while CO and He are always present in trace amounts. The He isotopic composition highlights a significant mantle component. CO2 and H2S concentrations higher than in the normal atmosphere can be stimulating for plant growth until certain levels and detrimental above them. As for many active geothermal areas of the world also H2S and CO2 concentrations measured in the area of Milos could be of concern for human health.

scholarly journals Air Concentrations of Gaseous Elemental Mercury and Vegetation–Air Fluxes within Saltmarshes of the Tagus Estuary, Portugal

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 228
Author(s):  
Rute Cesário ◽  
Nelson J. O’Driscoll ◽  
Sara Justino ◽  
Claire E. Wilson ◽  
Carlos E. Monteiro ◽  
...  
Keyword(s):  
Leaf Area ◽  
Elemental Mercury ◽  
Ambient Air ◽  
Tagus Estuary ◽  
Contaminated Site ◽  
Gaseous Elemental Mercury ◽  
Mercury Flux ◽  
Sarcocornia Fruticosa ◽  
Air Concentrations

In situ air concentrations of gaseous elemental mercury (Hg(0)) and vegetation–atmosphere fluxes were quantified in both high (Cala Norte, CN) and low-to-moderate (Alcochete, ALC) Hg-contaminated saltmarsh areas of the Tagus estuary colonized by plant species Halimione portulacoides (Hp) and Sarcocornia fruticosa (Sf). Atmospheric Hg(0) ranged between 1.08–18.15 ng m−3 in CN and 1.18–3.53 ng m−3 in ALC. In CN, most of the high Hg(0) levels occurred during nighttime, while the opposite was observed at ALC, suggesting that photoreduction was not driving the air Hg(0) concentrations at the contaminated site. Vegetation–air Hg(0) fluxes were low in ALC and ranged from −0.76 to 1.52 ng m−2 (leaf area) h−1 for Hp and from −0.40 to 1.28 ng m−2 (leaf area) h−1 for Sf. In CN, higher Hg fluxes were observed for both plants, ranging from −9.90 to 15.45 ng m−2 (leaf area) h−1 for Hp and from −8.93 to 12.58 ng m−2 (leaf area) h−1 for Sf. Mercury flux results at CN were considered less reliable due to large and fast variations in the ambient air concentrations of Hg(0), which may have been influenced by emissions from the nearby chlor-alkali plant, or historical contamination. Improved experimental setup, the influence of high local Hg concentrations and the seasonal activity of the plants must be considered when assessing vegetation–air Hg(0) fluxes in Hg-contaminated areas.

scholarly journals An Integrated Investigation of Atmospheric Gaseous Elemental Mercury Transport and Dispersion Around a Chlor-Alkali Plant in the Ossola Valley (Italian Central Alps)

Toxics ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 172
Author(s):  
Laura Fantozzi ◽  
Nicoletta Guerrieri ◽  
Giovanni Manca ◽  
Arianna Orrù ◽  
Laura Marziali
Keyword(s):  
Elemental Mercury ◽  
Background Concentration ◽  
Dispersion Pattern ◽  
Central Alps ◽  
Gaseous Elemental Mercury ◽  
Mercury Transport ◽  
Close Proximity ◽  
Potential Impact ◽  
Hg Accumulation

We present the first assessment of atmospheric pollution by mercury (Hg) in an industrialized area located in the Ossola Valley (Italian Central Alps), in close proximity to the Toce River. The study area suffers from a level of Hg contamination due to a Hg cell chlor-alkali plant operating from 1915 to the end of 2017. We measured gaseous elemental Hg (GEM) levels by means of a portable Hg analyzer during car surveys between autumn 2018 and summer 2020. Moreover, we assessed the long-term dispersion pattern of atmospheric Hg by analyzing the total Hg concentration in samples of lichens collected in the Ossola Valley. High values of GEM concentrations (1112 ng m−3) up to three orders of magnitude higher than the typical terrestrial background concentration in the northern hemisphere were measured in the proximity of the chlor-alkali plant. Hg concentrations in lichens ranged from 142 ng g−1 at sampling sites located north of the chlor-alkali plant to 624 ng g−1 in lichens collected south of the chlor-alkali plant. A north-south gradient of Hg accumulation in lichens along the Ossola Valley channel was observed, highlighting that the area located south of the chlor-alkali plant is more exposed to the dispersion of Hg emitted into the atmosphere from the industrial site. Long-term studies on Hg emission and dispersion in the Ossola Valley are needed to better assess potential impact on ecosystems and human health.

scholarly journals Occurrence of Volcanogenic Inorganic Mercury in Wild Mice Spinal Cord: Potential Health Implications

2021 ◽  
Author(s):  
A. Navarro-Sempere ◽  
M. García ◽  
A. S. Rodrigues ◽  
P. V. Garcia ◽  
R. Camarinho ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Inorganic Mercury ◽  
Elemental Mercury ◽  
Potential Health ◽  
Wild Mice ◽  
Gaseous Elemental Mercury ◽  
Lumbar Level ◽  
Quantification Analysis ◽  
Spinal Cord Potential ◽  
Cord Potential

AbstractMercury accumulation has been proposed as a toxic factor that causes neurodegenerative diseases. However, the hazardous health effects of gaseous elemental mercury exposure on the spinal cord in volcanic areas have not been reported previously in the literature. To evaluate the presence of volcanogenic inorganic mercury in the spinal cord, a study was carried out in São Miguel island (Azores, Portugal) by comparing the spinal cord of mice exposed chronically to an active volcanic environment (Furnas village) with individuals not exposed (Rabo de Peixe village), through the autometallographic silver enhancement histochemical method. Moreover, a morphometric and quantification analysis of the axons was carried out. Results exhibited mercury deposits at the lumbar level of the spinal cord in the specimens captured at the site with volcanic activity (Furnas village). A decrease in axon calibre and axonal atrophy was also observed in these specimens. Given that these are relevant hallmarks in the neurodegenerative pathologies, our results highlight the importance of the surveillance of the health of populations chronically exposed to active volcanic environments.

scholarly journals Simulation of atmospheric mercury depletion events (AMDEs) during polar springtime using the MECCA box model

2008 ◽  
Vol 8 (23) ◽  
pp. 7165-7180 ◽  
Author(s):  
Z.-Q. Xie ◽  
R. Sander ◽  
U. Pöschl ◽  
F. Slemr
Keyword(s):  
Aqueous Phase ◽  
Ozone Depletion ◽  
Elemental Mercury ◽  
Atmospheric Mercury ◽  
Box Model ◽  
Rate Coefficients ◽  
Mercury Species ◽  
Phase Reaction ◽  
Gaseous Elemental Mercury ◽  
Sea Salt Aerosol

Abstract. Atmospheric mercury depletion events (AMDEs) during polar springtime are closely correlated with bromine-catalyzed tropospheric ozone depletion events (ODEs). To study gas- and aqueous-phase reaction kinetics and speciation of mercury during AMDEs, we have included mercury chemistry into the box model MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere), which enables dynamic simulation of bromine activation and ODEs. We found that the reaction of Hg with Br atoms dominates the loss of gaseous elemental mercury (GEM). To explain the experimentally observed synchronous depletion of GEM and O3, the reaction rate of Hg+BrO has to be much lower than that of Hg+Br. The synchronicity is best reproduced with rate coefficients at the lower limit of the literature values for both reactions, i.e. kHg+Br≈3×10−13 and kHg+BrO≤1×10−15 cm3 molecule−1 s−1, respectively. Throughout the simulated AMDEs, BrHgOBr was the most abundant reactive mercury species, both in the gas phase and in the aqueous phase. The aqueous-phase concentrations of BrHgOBr, HgBr2, and HgCl2 were several orders of magnitude larger than that of Hg(SO3)22−. Considering chlorine chemistry outside depletion events (i.e. without bromine activation), the concentration of total divalent mercury in sea-salt aerosol particles (mostly HgCl42−) was much higher than in dilute aqueous droplets (mostly Hg(SO3)22−), and did not exhibit a diurnal cycle (no correlation with HO2 radicals).

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