Inhibition of bacterial perchlorate reduction by zero-valent iron
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- 作者：Joshua D. Shrout ; Aaron G.B. Williams ; Michelle M. Scherer and Gene F. Parkin
- 关键词：anaerobic bacteria ; bacterial reduction ; ferrous iron ; Mö ; ssbauer
- 刊名：Biodegradation
- 出版年：2005
- 出版时间：February, 2005
- 年：2005
- 卷：16
- 期：1
- 页码：23-32
- 全文大小：217 KB
- 刊物类别：Earth and Environmental Science
- 刊物主题：Environment
Soil Science and Conservation
Geochemistry
Terrestrial Pollution
Waste Water Technology, Water Pollution Control, Water Management and Aquatic Pollution
Waste Management and Waste Technology - 出版者：Springer Netherlands
- ISSN：1572-9729
文摘
Perchlorate was reduced by a mixed bacterial culture over a pH range of 7.0–8.9. Similar rates of perchlorate reduction were observed between pH 7.0 and 8.5, whereas significantly slower reduction occurred at pH 8.9. Addition of iron metal, Fe(0), to the mixed bacterial culture resulted in slower rates of perchlorate reduction. Negligible perchlorate reduction was observed under abiotic conditions with Fe(0) alone in a reduced anaerobic medium. The inhibition of perchlorate reduction observed in the presence of Fe(0) is in contrast to previous studies that have shown faster rates of contaminant reduction when bacteria and Fe(0) were combined compared to bacteria alone. The addition of Fe(0) resulted in a rise in pH, as well as precipitation of Fe minerals that appeared to encapsulate the bacterial cells. In experiments where pH was kept constant, the addition of Fe(0) still resulted in slower rates of perchlorate reduction suggesting that encapsulation of bacteria by Fe precipitates contributed to the inhibition of the bacterial activity independent of the effect of pH on bacteria. These results provide the first evidence linking accumulation of iron precipitates at the cell surface to inhibition of environmental contaminant degradation. Fe(0) was not a suitable amendment to stimulate perchlorate-degrading bacteria and the bacterial inhibition caused by precipitation of reduced Fe species may be important in other combined anaerobic bacterial–Fe(0) systems. Furthermore, the inhibition of bacterial activity by iron precipitation may have significant implications for the design of in situ bioremediation technologies for treatment of perchlorate plumes.