| 1. |
- Ferrara, R, et al.
(författare)
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Atmospheric mercury concentrations and fluxes in the Almaden District (Spain)
- 1998
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Ingår i: Atmospheric Environment. - 1352-2310. ; 32:22, s. 3897-3904
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Tidskriftsartikel (refereegranskat)abstract
- Atmospheric mercury levels around the world's largest mining and refining complex (Almaden, Spain) were determined during two field campaigns (September 1993 and February 1994) using both point monitors and lidar techniques. High mercury concentrations (0.1-5 mu g m(-3)) were measured over the village of Almaden in the prevailing wind direction. In the month of September the total mercury flux into the atmosphere was estimated to range from 600 to 1200 g h(-1). An attempt was made to measure the contribution from individual mercury sources. (C) 1998 Elsevier Science Ltd. All rights reserved.
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| 2. |
- Ferrara, R, et al.
(författare)
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Atmospheric mercury sources in the Mt. Amiata area, Italy
- 1998
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Ingår i: Science of the Total Environment. - 1879-1026. ; 213:1-3, s. 13-23
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Tidskriftsartikel (refereegranskat)abstract
- Mt. Amiata, located in southern Tuscany (Italy), is part of the geologic anomaly of the Mediterranean basin, which contains about 65% of the world's cinnabar (HgS) deposits. Atmospheric mercury emissions from the main sources (geothermal power plants, abandoned mine structures and spoil banks of roasted cinnabar ore) were determined by flux chamber and by LIDAR remote sensing. Mercury emissions from five geothermal power plants were on the order of 24 g h(-1) for each plant, a value that remains constant throughout the year. In the month of July, the mine spoils (covering an area of similar to 200000 m(2)) emit a few grams of mercury per hour, while the abandoned mine structures give off 100-110 g h(-1). These two mercury sources were strongly influenced by ambient temperature. The area affected by mercury sources displays an average air mercury concentration of 20 ng m(-3) during the summer and 10 ng m(-3) in winter. (C) 1998 Elsevier Science B.V.
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| 3. |
- Ferrara, R, et al.
(författare)
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Mercury degassing rate from mineralized areas in the Mediterranean basin
- 1997
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Ingår i: Water, Air and Soil Pollution. - 1573-2932. ; 93:1-4, s. 59-66
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge of the natural emissions of mercury in the Mediterranean basin, which has large cinnabar anomalies, has particular weight as these deposits could be an important source of atmospheric mercury. Data on the degassing rate of mercury from soils sampled both in mineralized areas (Mt. Amiata, Italy and Almaden, Spain) and rural areas are reported. Measurements were carried out 'in situ' using a transparent flux chamber and collecting the gaseous mercury on gold collectors. The highest values were observed in Almaden over the roasted cinnabar banks (up to 100 mu g/m(2)h) from past and present mining activity. In Italian rural areas the values of the volatilization rate of mercury are on the order of few ng/m(2)h. The degassing rate was observed to be strongly dependent on the ambient temperature and not only seasonal but also daily variations were measured in all the studied areas.
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| 4. |
- Weibring, Petter, et al.
(författare)
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Monitoring of volcanic sulphur dioxide emissions using differential absorption lidar (DIAL), differential optical absorption spectroscopy (DOAS), and correlation spectroscopy (COSPEC)
- 1998
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Ingår i: Applied Physics B. - : Springer Science and Business Media LLC. - 0946-2171. ; 67:4, s. 419-426
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Tidskriftsartikel (refereegranskat)abstract
- The total fluxes of sulphur dioxide from the Italian volcanoes Etna, Stromboli, and Vulcano were studied using optical remote sensing techniques in three shipborne field experiments (1992, 1994, and 1997). The main purpose of the experiments was to compare active (laser) techniques with passive monitoring. Differential absorption lidar (DIAL) measurements were implemented by placing the Swedish mobile lidar system on board the Italian research vessel Urania, sailing under the volcanic plumes. Simultaneously, the passive differential optical absorption spectroscopy (DOAS) technique was used for assessing the total overhead gas burden. Finally, correlation spectroscopy (COSPEC) was also implemented in one of the campaigns. Differences in integrated gas column assessment are expected and observed, mostly connected to complex scattering conditions influencing the passive measurements. Since such measurements are much employed in routine volcanic monitoring it is of great interest to model and provide corrections to the raw data obtained. Lidar measurements proved to be quite useful for this purpose. By combining the integrated gas concentration over the plume cross section with wind velocity data, SO2 fluxes of the order of 1000, 100, and 10 tonnes/day were measured for Mt. Etna, Stromboli, and Vulcano, respectively.
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