MICROBES, Mn OXYHYDROXIDES AND METALS: MICROBIAL BIOGEOCHEMISTRY IN ACID ROCK DRAINAGE

摘要

Reactive metal transport in acid rock drainage (ARD) environments is increasingly appreciated as a microbially mediated process. Understanding the linkages amongst microbial function, system geochemical conditions and metal behaviour, will help to provide a mechanistic foundation from which to design mitigative and/or bioremediation approaches for ARD. My group has been investigating the biogeochemical processes controlling metal dynamics in tailings derived streams in an ARD environment (Sudbury, ON), using an integrated approach combining geochemical, microbiological and microscopic techniques. These tailings associated streams are acidic (pH < 3.5) with high metal loads (nMolar - mMolar) and flourishing microbial biofilms. Whilst microbial biofilms are thin layer structures (typically hundreds of microns, to a few millimeters in thickness), their role in controlling overall system metal transport may be significant, due to the high rates of microbial activity and attendant geochemical reactivity, concentrated within these structures. Investigation by my group, of the biogeochemical processes controlling biofilm metal behaviour has identified associated biominerals of Mn oxyhydroxides, as key metal sorbents.