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The polymetallic (Zn, Cu, Pb, Fe, Ag) sulfide deposit of Fenice Capanne, southern Tuscany (Italy), was mined at least 6–7th centuries B.C. until 1985. Mine wastes include dumps of roasting products and excavation wastes, mainly dating back to the 19th century, and flotation tailings produced during the period 1950–1984. The mine wastes show significant contents of polluting elements [maximum values (mg/kg) in flotation tailings and roastings As: 1,100; Cu: 7,500; Pb:10,100; Zn: 13,600]. Tailing piles show more intense leaching and acidification compared with later basin filling tailings. The greater effective porosity, as a result of coarser grain size, and the unsaturated conditions that occur in the tailing piles have enhanced sulfide weathering, compared with the fine grained and nearly saturated flotation material present in the settling basins. However, flotation tailing samples show overall negative values of net neutralization potential (NNP), as determined by a standard Sobek test. This emphasizes the importance of maintaining the present hydraulic conditions within the basins to prevent the generation of acid drainage in future. The alteration of mine waste materials have produced pollution in surficial waters and sediments. The pollutant transport in surficial waters occurs mainly as suspended fine-grained sediments containing traces of heavy metals. A possible remediation plan could include building a settling pond for drainage waters, and moving the polluted sediments and unconfined tailing materials into the basins.

Mining activity in the Boccheggiano-Fontalcinaldo area (Southern Tuscany) dates back at least to the 16th century AD and lasted up to very recent times. Copper-rich hydrothermal veins, massive pyrite deposits, and their gossans were exploited. Two mine waste dumps (Fontalcinaldo, Fontebona), one flotation tailings impoundment (Gabellino), and one roasting/smelting waste dump (Merse-Ribudelli) in the study area were selected to ascertain the environmental effects of such protracted mining activity. Primary waste mineralogy is mainly characterized by pyrite, gypsum, quartz, carbonates, chlorites, and micas. Secondary oxidation mineralogy includes Fe and Cu sulfates and hydroxy sulfates, Cu carbonates, Fe and Al oxyhydroxides, and other phases [neogenic cassiterite at Fontalcinaldo; probable calkinsite, (Ce,La)2(CO3)3· 4H2O, at Fontebona]. Mine waste samples show extremely variable contents of toxic elements (Cu, Pb, Zn, Bi, Cd, As), with average values in the order of hundreds to thousands of parts per million (except for Bi and Cd). In some samples, the abundance of proper minerals of these metals cannot account for the entire metal load. Conceivably, either solid solution substitutions or adsorption processes contribute to the intake of released metals into newly formed minerals. Release and transport of pollutants was affected to variable degrees by acid-neutralization processes. The highest metal and acid concentrations occur close to the investigated wastes and rapidly decrease moving downstream some hundreds of meters or less, with the partial exception for Mn and Fe. Other than dilution effects, this phenomenon may be ascribed to metal adsorption and precipitation of solid phases.