Dissimilatory iron-reducing bacteria can influence the reduction of carbontetrachloride by iron metal

Little is known about the long-term performance of zerovalent iron (Fe-0) s ubsurface barriers. Groundwater exposure induces corrosion processes that c an passivate the Fe-0 surface and decrease barrier reaction rates. We prese nt evidence that dissimilatory iron-reducing bacteria (DIRB) can stimulate the rate of carbon tetrachloride (CT) transformation in the presence of cor roded iron. The DIRE, Shewanella alga BrY, adhered to the corroded Fe surfa ces that showed little or no capacity to transform CT. The addition of BrY to these systems with decreased CT transformation rates resulted in increas ed ferrous iron concentrations and increased CT transformation to chlorofor m (CF). The results suggest that DIRE can have an influence on the long-ter m performance of Fe-0 barriers.