The study area is located in the about 200 ky old silicic volcanic complex of Mt. Amiata (Tuscany, central Italy), which is mainly characterized by dacitic, rhyodacitic and minor olivine-latitic products. In two sites (Bagnore and Piancastagnaio), geothermal fluids are currently exploited to produce electricity, while in the past Mt. Amiata was considered the fourth largest district of mercury in the world, the ore deposit containing 0.6-2% Hg. The most important mining site was located at Abbadia San Salvatore, in the eastern flank of Mt. Amiata. Although cinnabar was used since the Etruscan time, the industrial extraction of metallic mercury only commenced in the last century by using Spirek and Cermak-Spirek, Gould and Nesa furnaces. The mining activity ended in 1982 after about 100 years of exploitation. The abandoned mining structures presently occupy a surface of ~65 ha. In the production area at least 270,000 m3 of waste material (post-roasting products and unprocessed materials, also deriving from other Hg exploitation areas from Mt. Amiata), with an average thickness of 6 m, were stored adjacently the buildings hosting the furnaces to fill a topographic low. A shallow (from about 4 to 16 m below the ground level) multi-aquifer formed inside this “landfill”. The present work shows the analytical results of groundwater samples collected during a 3-years long monitoring (7 geochemical surveys from February 2013 to January 2016) from old and recently drilled piezometers located inside and outside the former Hg-mining area of Abbadia San Salvatore, including a water sample from an about 40 m deep piezometer. The aims were those to: i) evaluate the concentrations and the spatial and temporal variations of the main solutes and those of Hg, and As and Sb (the two latter elements being commonly associated with mercury) and ii) define at what extent a vertical and horizontal contamination plume of these metals distributed. This monitoring activity is prodromal to any remediation action that is expected to occur in a couple of years.
Distribution of mercury, antimony and arsenic in the shallow groundwater system from the former Hg-mining areas of Abbadia San Salvatore (Tuscany, central Italy) / Vaselli O., Nisi B., Rappuoli D., Bianchi F., Giannini L., Cabassi J., Tassi F., Venturi S.. - ELETTRONICO. - (2016), pp. 0-0. (Intervento presentato al convegno 18th International Conference on Heavy Metals in the Environment).
Distribution of mercury, antimony and arsenic in the shallow groundwater system from the former Hg-mining areas of Abbadia San Salvatore (Tuscany, central Italy)
Vaselli O.;Rappuoli D.;Giannini L.;Cabassi J.;Tassi F.;Venturi S.
2016
Abstract
The study area is located in the about 200 ky old silicic volcanic complex of Mt. Amiata (Tuscany, central Italy), which is mainly characterized by dacitic, rhyodacitic and minor olivine-latitic products. In two sites (Bagnore and Piancastagnaio), geothermal fluids are currently exploited to produce electricity, while in the past Mt. Amiata was considered the fourth largest district of mercury in the world, the ore deposit containing 0.6-2% Hg. The most important mining site was located at Abbadia San Salvatore, in the eastern flank of Mt. Amiata. Although cinnabar was used since the Etruscan time, the industrial extraction of metallic mercury only commenced in the last century by using Spirek and Cermak-Spirek, Gould and Nesa furnaces. The mining activity ended in 1982 after about 100 years of exploitation. The abandoned mining structures presently occupy a surface of ~65 ha. In the production area at least 270,000 m3 of waste material (post-roasting products and unprocessed materials, also deriving from other Hg exploitation areas from Mt. Amiata), with an average thickness of 6 m, were stored adjacently the buildings hosting the furnaces to fill a topographic low. A shallow (from about 4 to 16 m below the ground level) multi-aquifer formed inside this “landfill”. The present work shows the analytical results of groundwater samples collected during a 3-years long monitoring (7 geochemical surveys from February 2013 to January 2016) from old and recently drilled piezometers located inside and outside the former Hg-mining area of Abbadia San Salvatore, including a water sample from an about 40 m deep piezometer. The aims were those to: i) evaluate the concentrations and the spatial and temporal variations of the main solutes and those of Hg, and As and Sb (the two latter elements being commonly associated with mercury) and ii) define at what extent a vertical and horizontal contamination plume of these metals distributed. This monitoring activity is prodromal to any remediation action that is expected to occur in a couple of years.
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