BIOGEOCHEMICAL REMOVAL OF RDX USING IRON OXIDE AND GEOBACTER METALLIREDUCENS GS-15

摘要

Biogeochemical interactions between iron-reducing bacteria (e.g., Geobacter metallireducens GS-15) and iron oxides could promote the removal of redox-sensitive pollutants, such as RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) from contaminated soils and groundwater. RDX, a common contaminant at military installations, is a suspected carcinogen that is relatively recalcitrant to microbial degradation. RDX, however, is prone to undergo chemical reduction. Our results suggest that iron-reducing bacteria may enhance RDX removal not only through biotransformation but also by the production of reactive, biogenic iron oxides such as magnetite that can reduce RDX abiotically. Interestingly, biogenic magnetite was more reactive than chemically synthesized magnetite. Consequently, iron-reducing bacteria could improve the performance of iron barriers and increase the reactivity of some mineral surfaces for enhanced natural attenuation of priority pollutants that are prone to be abiotically reduced.