COPPER TOLERANCE IN IRON-REDUCING BACTERIA - IMPLICATIONS FOR COPPER MOBILIZATION IN SEDIMENTS

Iron-reducing bacteria enriched from a Cu-contaminated sediment were m ore tolerant of Cu adsorbed to hydrous ferric oxide (HFO) than were pr istine-sediment bacteria. Tolerance was enhanced by increasing the Cu concentration in the culture medium over time, enabling the bacteria t o begin reducing Cu-contaminated HFO sooner and at a faster rate than Cu-intolerant bacteria. Copper tolerance confers a greater ability to reduce contaminated HFO and may result in a greater potential for Cu m obilization in sediments.