Solubility of metals in aerosol samples from Mount Etna during the EPL-REFLECT campaign

2020 ◽  
Author(s):  
Chiara Giorio ◽  
Sara D'Aronco ◽  
Lidia Soldà ◽  
Salvatore Giammanco ◽  
Alessandro La Spina ◽  
...  
Keyword(s):  
Trace Metals ◽  
Human Health ◽  
Organic Compounds ◽  
Organic Ligand ◽  
Mount Etna ◽  
Urban Site ◽  
Explosive Eruptions ◽  
Chemical Components ◽  
Volcanic Plume ◽  
Volcanic Plumes

<p>Volcanoes emit a chemically complex cocktail of gases and aerosols into the atmosphere, which can affect Earth’s climate (1) and human health. The vast majority of volcanogenic fatalities involve the obvious thermal and physical injuries resulting from an eruption, but many of the emissions from volcanoes are toxic and include compounds such as sulfates and metals, which are known to disrupt biological systems (2). Yet, there is a lack of knowledge on the toxicity of compounds found in volcanic plumes and their fate in the atmosphere.</p><p>Research has focussed on the impacts of large-magnitude explosive eruptions. While emissions from many non-explosive eruptions are continuous and prolonged, their climatic and potential effects on human health have not been studied extensively. Once the plume disperses in the atmosphere, the aerosol particle components can mix and interact with oxidants and organic compounds present in the atmosphere. How these chemical components interact and how the interactions affect the Earth’s climate, particle toxicity and human health is largely unknown especially for trace metals.</p><p>In the framework of the EPL-REFLECT (Etna Plume Lab – near-source estimations of Radiative EFfects of voLcanic aErosols for Climate and air quality sTudies), a field campaign on Mount Etna was done in July 2019 in which samples of atmospheric aerosol were collected during non-explosive degassing activity. Samples were collected both at the crater and in a transect following the volcanic plume down slope to the closest inhabited areas. Samples were analysed for trace metals and organic compounds, including solubility tests (3) to assess how tropospheric processing of the aerosol affects metal bioavailability and potentially the toxicity of the aerosol.</p><p> </p><p><strong>(1)</strong> von Glasow, R. 2010. Atmospheric chemistry in volcanic plumes. Proceedings of the National Academy of Sciences, vol. 107, pp. 6594–6599., DOI: 10.1073/pnas.0913164107</p><p><strong>(2)</strong> Weinstein, P., Horwell, C.J., Cook, A. 2013. Volcanic Emissions and Health. In: Essentials of Medical Geology, Springer Netherlands, Dordrecht, pp. 217–238., DOI: 10.1007/978-94-007-4375-5_10</p><p><strong>(3)</strong> Tapparo, A., Di Marco, V., Badocco, D., D’Aronco, S., Soldà, L., Pastore, P., Mahon, B.M., Kalberer, M., Giorio, C. 2019. Formation of metal-organic ligand complexes affects solubility of metals in airborne particles at an urban site in the Po Valley. Chemosphere, in press., DOI: 10.1016/j.chemosphere.2019.125025</p>

scholarly journals Detection of Volcanic Plumes by GPS: the 23 November 2013 Episode on Mt. Etna

2015 ◽  
Vol 57 ◽  
Author(s):  
Massimo Aranzulla ◽  
Flavio Cannavò ◽  
Simona Scollo
Keyword(s):  
Signal To Noise Ratio ◽  
Explosive Eruptions ◽  
Volcanic Plume ◽  
Test Case ◽  
Signal To Noise ◽  
Volcanic Plumes ◽  
Gps Network ◽  
Mt Etna ◽  
New Challenges ◽  
Aviation Operations

<p>The detection of volcanic plumes produced during explosive eruptions is important to improve our understanding on dispersal processes and reduce risks to aviation operations. The ability of Global Position-ing System (GPS) to retrieve volcanic plumes is one of the new challenges of the last years in volcanic plume detection. In this work, we analyze the Signal to Noise Ratio (SNR) data from 21 permanent stations of the GPS network of the Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo, that are located on the Mt. Etna (Italy) flanks. Being one of the most explosive events since 2011, the eruption of November 23, 2013 was chosen as a test-case. Results show some variations in the SNR data that can be correlated with the presence of an ash-laden plume in the atmosphere. Benefits and limitations of the method are highlighted.</p>

scholarly journals Observation and modelling of ozone-destructive halogen chemistry in a passive degassing volcanic plume

2021 ◽  
Author(s):  
Luke Surl ◽  
Tjarda Roberts ◽  
Slimane Bekki
Keyword(s):  
Heterogeneous Reactions ◽  
Mount Etna ◽  
Volcanic Plume ◽  
Activation Process ◽  
Aerosol Formation ◽  
Strong Negative Correlation ◽  
Volcanic Plumes ◽  
Ozone Loss ◽  
Halogen Chemistry ◽  
Aircraft Observations

Abstract. Volcanoes emit halogens into the atmosphere that undergo chemical cycling in plumes and cause destruction of ozone. The impacts of volcanic halogens are inherently difficult to measure at volcanoes, and the complexity of the chemistry, coupled with the mixing and dispersion of the plume, makes the system challenging to model numerically. We present aircraft observations of the Mount Etna plume in the summer of 2012, when the volcano was passively degassing. Measurements of SO2 – an indicator of plume intensity – and ozone were made in the plume a few 10s of km from the source, revealing a strong negative correlation between ozone and SO2 levels. From these observations we estimate a mean in-plume ozone loss rate of 1.3 × 10−5 molecules of O3 per second per molecule of SO2. This value is similar to observation-derived estimates reported very close to the Mount Etna vents, indicating continual ozone loss in the plume up to at least 10's km downwind. The chemically reactive plume is simulated using a new numerical 3D model WRF-Chem Volcano (WCV), a version of WRF-Chem we have modified to incorporate volcanic emissions (including HBr and HCl) and multi-phase halogen chemistry. We used nested grids to model the plume close to the volcano at 1 km. The focus is on the early evolution of passively degassing plumes aged less than one hour and up to 10's km downwind. The model reproduces the so-called bromine explosion: the daytime bromine activation process by which HBr in the plume is converted to other more reactive forms that continuously cycle in the plume. These forms include the radical BrO, a species whose ratio with SO2 is commonly measured in volcanic plumes as an indicator of halogen ozone-destroying chemistry. We track the modelled partitioning of bromine between its forms. The model yields in-plume BrO / SO2 ratios (around 10−4 mol/mol) similar to those observed previously in Etna plumes. The modelled BrO / SO2 is lower in plumes which are more dilute (e.g. at greater windspeed). It is also slightly lower in plumes in the middle of the day compared than in the morning and evening, due to BrO's reaction with diurnally varying HO2. Sensitivity simulations confirm the importance of near-vent products from high temperature chemistry, notably bromine radicals, in initiating the ambient temperature plume halogen cycling. Note also that heterogeneous reactions that activate bromine also activate a small fraction of the emitted chlorine; the resulting production of chlorine radical Cl causes a strong reduction in the methane lifetime and increasing formation of HCHO in the plume. Modelled rates of ozone depletion are found to be similar to those derived from aircraft observations. Ozone destruction in the model is controlled by the processes that recycle bromine, with about three-quarters of this recycling occurring via reactions between halogen oxide radicals. Through sensitivity simulations, a relationship between the magnitude of halogen emissions and ozone loss is established. Volcanic halogens cycling impacts profoundly the overall plume chemistry, notably hydrogen oxide radicals (HOx), nitrogen oxides (NOx), sulfur, and mercury chemistry. In the model, it depletes HOx within the plume, increasing the lifetime of SO2 and hence slowing sulfate aerosol formation. Halogen chemistry also promotes the conversion of NOx into nitric acid (HNO3). This, along with the displacement of nitrate out of background aerosols in the plume, results in enhance HNO3 levels and an almost total depletion of NOx in the plume. The halogen-mercury model scheme is simple but includes newly-identified photo-reductions of mercury halides. With this set-up, the mercury oxidation is found to be slow and in near-balance with the photo-reduction in the plume. Overall, the model findings demonstrate that halogen chemistry has to be considered for a complete understanding of sulfur, HOx, reactive nitrogen, and mercury chemistry, and of the formation of sulfate particles in volcanic plumes.

scholarly journals Observation and modelling of ozone-destructive halogen chemistry in a passively degassing volcanic plume

2021 ◽  
Vol 21 (16) ◽  
pp. 12413-12441
Author(s):  
Luke Surl ◽  
Tjarda Roberts ◽  
Slimane Bekki
Keyword(s):  
Ambient Temperature ◽  
Time Of Day ◽  
Heterogeneous Reactions ◽  
Mount Etna ◽  
Volcanic Plume ◽  
Aerosol Formation ◽  
Volcanic Plumes ◽  
Ozone Loss ◽  
Halogen Chemistry ◽  
Aircraft Observations

Abstract. Volcanoes emit halogens into the atmosphere that undergo complex chemical cycling in plumes and cause destruction of ozone. We present a case study of the Mount Etna plume in the summer of 2012, when the volcano was passively degassing, using aircraft observations and numerical simulations with a new 3D model “WRF-Chem Volcano” (WCV), incorporating volcanic emissions and multi-phase halogen chemistry. Measurements of SO2 – an indicator of plume intensity – and ozone were made in the plume a few tens of kilometres from Etna, revealing a strong negative correlation between ozone and SO2 levels. From these observations, using SO2 as a tracer species, we estimate a mean in-plume ozone loss rate of 1.3×10−5 molecules of O3 per second per molecule of SO2. This value is similar to observation-based estimates reported very close to Etna's vents, indicating continual ozone loss in the plume up to at least tens of kilometres downwind. The WCV model is run with nested grids to simulate the plume close to the volcano at 1 km resolution. The focus is on the early evolution of passively degassing plumes aged less than 1 h and up to tens of kilometres downwind. The model is able to reproduce the so-called “bromine explosion”: the daytime conversion of HBr into bromine radicals that continuously cycle in the plume. These forms include the radical BrO, a species whose ratio with SO2 is commonly measured in volcanic plumes as an indicator of halogen ozone-destroying chemistry. The species BrO is produced in the ambient-temperature chemistry, with in-plume BrO / SO2 ratios on the order of 10−4 mol/mol, similar to those observed previously in Etna plumes. Wind speed and time of day are identified as non-linear controls on this ratio. Sensitivity simulations confirm the importance of near-vent radical products from high-temperature chemistry in initiating the ambient-temperature plume halogen cycling. Heterogeneous reactions that activate bromine also activate a small fraction of the emitted chlorine; the resulting production of chlorine radical Cl strongly enhances the methane oxidation and hence the formation of formaldehyde (HCHO) in the plume. Modelled rates of ozone depletion are found to be similar to those derived from aircraft observations. Ozone destruction in the model is controlled by the processes that recycle bromine, with about three-quarters of this recycling occurring via reactions between halogen oxide radicals. Through sensitivity simulations, a relationship between the magnitude of halogen emissions and ozone loss is established. Volcanic halogen cycling profoundly impacts the overall plume chemistry in the model, notably hydrogen oxide radicals (HOx), nitrogen oxides (NOx), sulfur, and mercury chemistry. In the model, it depletes HOx within the plume, increasing the lifetime of SO2 and hence slowing sulfate aerosol formation. Halogen chemistry also promotes the conversion of NOx into nitric acid (HNO3). This, along with the displacement of nitrate out of background aerosols in the plume, results in enhanced HNO3 levels and an almost total depletion of NOx in the plume. The halogen–mercury model scheme is simple but includes newly identified photo-reductions of mercury halides. With this set-up, the mercury oxidation is found to be slow and in near-balance with the photo-reduction of the plume. Overall, the model findings demonstrate that halogen chemistry has to be considered for a complete understanding of sulfur, HOx, reactive nitrogen, and mercury chemistry and of the formation of sulfate particles in volcanic plumes.

Construction of an airborne chemiluminescence ozone monitor for volcanic plumes

2021 ◽  
Author(s):  
Ellen Bräutigam ◽  
Nicole Bobrowski ◽  
Jonas Kuhn ◽  
Maja Rüth ◽  
Christopher Fuchs ◽  
...  
Keyword(s):  
Trace Gases ◽  
Standard Technique ◽  
Field Measurements ◽  
Ambient Air ◽  
Reaction Chamber ◽  
Significant Decline ◽  
Mount Etna ◽  
Volcanic Plume ◽  
Volcanic Plumes ◽  
Absorption Features

&lt;p&gt;Volcanic plumes contain traces of bromine monoxide, BrO, which catalyze destruction of ozone, O&lt;sub&gt;3&lt;/sub&gt;, mixed into the plume. Therefore, local depletion of O&lt;sub&gt;3 &lt;/sub&gt;in the plume could be possible. However, calculations comparing mixing with the rate of O&lt;sub&gt;3 &lt;/sub&gt;destruction suggest that no significant decline in the O&lt;sub&gt;3&lt;/sub&gt; concentration should be expected. On the other hand several studies at different volcanoes have found varying degrees of O&lt;sub&gt;3&lt;/sub&gt; depletion inside the plume. So far, ozone and its concentration distribution in volcanic plumes have only been insufficiently determined. Reliable ozone measurements would make a decisive contribution to the understanding of volcanic plume chemistry.&lt;/p&gt; &lt;p&gt;The standard technique for ambient O&lt;sub&gt;3&lt;/sub&gt; monitoring is the short-path ultraviolet (UV) absorption instrument. But in volcanic plumes this technique suffers from strong interference of the overlapping SO&lt;sub&gt;2&lt;/sub&gt; absorption features in the UV. SO&lt;sub&gt;2&lt;/sub&gt; is one of the major compounds in volcanic plumes.&lt;/p&gt; &lt;p&gt;We want to overcome this problem by relying on the chemiluminescence (CL) reaction between ozone and ethene, a standard technique for O&lt;sub&gt;3&lt;/sub&gt; measurement in the 1970s and 1980s, which we found to have no interference from trace gases abundant in volcanic plumes. The key component of a CL O&lt;sub&gt;3&lt;/sub&gt;-instrument is a reaction chamber, where ethene is mixed into the ambient air and a photomultiplier tube detects the resulting photons.&lt;/p&gt; &lt;p&gt;Field measurements with existing CL O&lt;sub&gt;3&lt;/sub&gt;-monitors are complicated, because they are usually heavy and bulky. Therefore we designed a more compact and lightweight version (10 kg backpack size CL instrument), which was used in a field study at Mount Etna. However, the campaign was restricted to plumes that are pushed down to ground in areas accessible by foot.&lt;/p&gt; &lt;p&gt;Here we report on a further improved version of the instrument weighing around 1 kg, which we can mount onto a drone to carry it into the plume. In particular, we describe the design advances making the reduction in weight and size possible.&lt;/p&gt;

Removal of Trace Metals From Wastewater by Activated Carbon

1973 ◽  
Vol 8 (1) ◽  
pp. 110-121
Author(s):  
A. Netzer ◽  
J.D. Norman
Keyword(s):  
Activated Carbon ◽  
Trace Metals ◽  
Organic Compounds ◽  
The Other ◽  
Published Data ◽  
Ph Adjustment ◽  
Nickel Silver ◽  
Ph Range ◽  
Carbon Treatment ◽  
Cobalt Copper

Abstract The merits of activated carbon for removal of organic compounds from wastewater have been well documented in the literature. On the other hand there is a lack of published data on the use of activated carbon for the removal of trace metals from wastewater. Experiments were designed to assess the possibility that activated carbon treatment would remove aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, silver and zinc from wastewater. All metals studied were tested over the pH range 3-11. Greater than 99.5% removal was achieved by pH adjustment and activated carbon treatment for most of the metals tested.

Sorption of radionuclides to a cementitious backfill material under near-field conditions

2012 ◽  
Vol 76 (8) ◽  
pp. 3401-3410 ◽  
Author(s):  
M. Felipe-Sotelo ◽  
J. Hinchliff ◽  
N. Evans ◽  
P. Warwick ◽  
D. Read
Keyword(s):  
Organic Compounds ◽  
Degradation Products ◽  
Cellulose Degradation ◽  
Near Field ◽  
Organic Ligand ◽  
Sorption Isotherms ◽  
Field Conditions ◽  
Sorption Behaviour ◽  
Backfill Material ◽  
Order Of Magnitude

AbstractThe sorption behaviour of I−, Cs+, Ni2+, Eu3+, Th4+ and UO2+2on NRVB (Nirex reference vault backfill) a possible vault backfill, at pH 12.8 was studied. Sorption isotherms generated were compared to results obtained in the presence of cellulose degradation products (CDP). Whereas Cs was not affected by the presence of the organic compounds, a notable reduction in the sorption of Th and Eu to cement was observed. The results also indicated limited removal of Ni from solution (with or without an organic ligand) by sorption, the concentration in solution seemingly being determined solely by solubility processes. In the case of uranium, the presence of CDP increased the sorption to cement by almost one order of magnitude. Further studies into the uptake of CDP by cement are being undertaken to identify the mechanism(s) responsible.

Supramolecular Self-Assembly of Nitro-incorporated Quinoxaline Framework: Insights into the Origin of Fluorescence Turn-on Response towards Benzene group of VOCs

The Analyst ◽  
2021 ◽  
Author(s):  
Megha Basak ◽  
Gopal Das
Keyword(s):  
Volatile Organic Compounds ◽  
Human Health ◽  
Organic Compounds ◽  
Self Assembly ◽  
Turn On ◽  
Volatile Organic ◽  
Fluorescence Turn On

Hazardous volatile organic compounds (VOCs) can significantly impact human health and the environment. Hence, the detection of VOCs has become foremost important. Quinoxaline-based fluorimetric probe (1) unveils a notable “Turn-On”...

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