Research Article
Tallium and Other Heavy Metals Occurences in Acid Mine Drenage, Baccatoio Creek, Apuane Alps, Italy
Franceschini FIn this paper we present the geochemical data related to mine Acid Drainage (AMD) contamination along the Baccatoio Creek (Apuan Alps, Tuscany) with focus to some many toxic heavy metals as Cadmium, Mercury, Antimony, Arsenic and Thallium. The formation of AMD and the contaminants associated with it has been described by some as the largest environmental problem facing the world mining industry [1,2]. In the Baccatoio basin, more than 20 kilometers of streams are affected by acid drainage from two abandoned mine sites named Mt.Arsiccio and Valdicastello. These mines were development on some small Ba-Fe deposit which was operated prior to 1989. The main ore bodies are an almost conformable lens characterized by a distinct zoning, with pyrite+baryte at the bottom and iron oxides (magnetite and hematite) + baryte at the top, with various accessory sulfides and sulphosalts bearing heavy metals. The mineralization are hosted into and at the contact between phyllites, related to the paleozoic basement of Apuan Alps, and Triassic dolomitic limestones of the Grezzoni formation. The AMD are generated essentially into underground workings (tunnels) and are scattered along the watercourse from the mine culverts. In the study area the conceptual model related to groundwater, freshwater and stream sediments distribution shows that Tl has a different behavior than other heavy metals present in AMD. Indeed this very high toxic element is missing or present in very low concentrations in sediments while persists in relatively high concentrations in the aqueous matrix. Occurrence of heavy metals in groundwater used for drinking water is confirmed only for Tl