Heavy metal contents related to mine dumps of Tuscany

Three millennia of intense mining activity in Tuscany have left profound marks in the landscape, culture and history of the region, including numerous abandoned mine sites that pose a potential threat to the environment. Since 1992, the Department of Earth Science of Florence has been conducting a research program to assess the environmental impact of abandoned pyrite and base-metal sulphide mines, including Boccheggiano (Cu and pyrite), Fenice Capanne (Cu-Pb-Zn-Ag) and Campiglia M.ma (Cu-Pb-Zn-Ag) in Southern Tuscany, Bottino (Pb-Ag-Zn) in northern Tuscany. The wastes at the four localities include jigging and flotation tailings, excavation wastes and smelter roastings. The dumps show high, albeit variable, contents of toxic elements such as As, Cd, Cu, Pb and Zn. Stream waters of the Boccheggiano, Fenice Capanne and Bottino areas show variable degrees of pollution. Highest heavy metal contents, in particular for As, Cd, Cu, Pb, Zn, and acid concentrations usually occur close to wastes and rapidly decrease moving downstream from the wastes. The soils developed on (and in close proximity to) waste piles usually show high heavy metal contents, similar those of waste piles. In all areas, natural soils far from waste piles more than 50 m up to 20 km show variable contents of pollutants (As, Cu, Pb, Zn).