PARENT SESSION
PW5 - Microbial Treatment and Biorecovery of Acid Mine Drainage
Wednesday, 20 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P763) Importance of the iron cycle in the generation of Acid Mine Drainage, the Tinto River case.
Amils, Ricardo*,1,2, Gomez, F2, Rodriguez, N2, Fernandez-Remolar, D2, Malki, M1, Duran, C1, Zuluaga, J1, 1 U. Autonoma de Madrid, Cantoblanco, Madrid, SPAIN2 U. Autonoma de Madrid, Torrejon de Ardoz, Madrid, SPAIN
ABSTRACT- The Tinto River (Iberian Pyritic Belt) is a 100 km long river with a characteristic dark red color given by the high concentration of ferric iron (up to 20 g/L) and other heavy metals (Cu, Zn, As, Cr) maintained in solution at the constant acidic conditions (mean pH of 2.3) of the system. The extreme conditions of the habitat are the consequence of the very active metabolism performed by the chemolithotrophic microorganisms thriving in its waters. The use of conventional microbial ecology (isolation from enrichment cultures and characterization) and molecular ecology techniques (FISH and DGGE) allowed to identify and quantify the prokaryotes growing on the rich sulfidic complex minerals of the Iberian Pyritic Belt. Both, sulfur and iron metabolizing microorganisms have an important role in the Tinto system, but the iron cycle seems to play a critical role in this habitat. A geomicrobiological model has been generated in which most of the physico-chemical and biological characteristics of the ecosystem can be explained. The biohydrometallurgical implications of the model will be discussed.
Key words: bioleaching, Iron cycle, sulfur cycle, Tinto River, AMD