Environmental problems related to sulfide mining in Tuscany

Mining activity in Tuscany, which dates to at least Etruscan times, has left many abandoned mines and mine wastes that represent a potential source of heavy-metal pollution. Three areas were studied: the Cu and pyrite mines at Boccheggiano and the Fenice Capanne Cu-Pb-Zn-Ag mine in southern Tuscany, and the Bottino Pb-Ag-Zn mine in the Apuane Alps of northern Tuscany. The wastes at the three localities include one or more of tailings, excavation wastes, and roastings from smelting. The wastes show high, albeit extremely variable, contents of toxic elements such as As, Bi, Cd, Cu, Pb, and Zn. The extent of primary-sulfide weathering and of release of heavy metals is controlled by the original content of metal-bearing and buffering phases in the wastes, the morphology and particle size in the waste piles, and subordinately, the age of the dumps. The potential threat of the heavy metals to the environment is partly subdued by fixation in relatively stable solid phases. In particular, the results for the Boccheggiano area suggest that pollutant transport over long distances mainly occurs as suspended particulate matter in streams. Gravitational runoff, aeolian transport, and transport in solution are limited to the immediate proximity of the sources.