Atmospheric mercury sources in the Mt. Amiata area, Italy

Mt. Amiata, located in southern Tuscany (Italy), is part of the geologic anomaly of the Mediterranean basin, which contains about 65% of the worldʹs 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 ∼200 000 m2) 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.