Uranium Remediation

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Uranium Remediation

• Is bioremediation a feasible solution?
• Morgan Chamberlin

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Questions To Be Answered

• Where does uranium contamination come from?
• What is remediation and what are some commonly
  used techniques?
• What is bioremediation and what advantages does
  this technique offer?

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Sources of Uranium
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Remediation Techniques

• Purpose
• Remove or reduce the source of contamination
• Prevent further exposure by blocking exposure
  pathways
• Methods include physical, chemical, and
  biological techniques
• Dependent upon site characteristics

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Remediation Techniques

• Physical Techniques
• Soil capping and washing
• Solidification
• Chemical Techniques
• Chemical Degradation
• Oxidation-Reduction reactions
• Solubility processes

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Remediation Techniques

• Cons
• Can be expensive
• Land disposal restrictions
• Lack specificity
• Possibility of further contamination

• Pros
• Well-researched
• Commonly used

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Bioremediation

• Purpose
• exploit naturally occurring biodegradative
  processes to clean up contaminated sites.
• Use metabolic characteristics of microorganisms,
  fungi, and plants
• Uranium Biodegradation
• Mobile U(VI) Uranyl, (UO2)2
• Immobile U(IV) Uraninite, UO2

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Geobacter species

• Gram-negative, anaerobic
• Soil and aqueous habitats
• Studies
• Ability to perform chemotaxis
• Cytochromes in outer membrane couple reduce heavy
  metals
• Application
• Bioremediation of uranium and other heavy metals
• Case Study
• Oakridge field research center

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Case Study- Oakridge Site, TN
Site polluted with millions of gallons of uranium
and nitric waste from uranium plating activities
over a period of 31 years. Contaminated S-3
ponds capped and converted to a parking lot in
1983. Oakridge field research center
established in 2001 to perform bioremediation
experiments
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Oakridge Site Continued

• Experimental Design
• Series of wells drilled throughout site adjacent
  to former S-3 ponds (Area 3)
• Injection of ethanol to stimulate Geobacter
  metabolic activity after soil conditioning
  processes
• Ethanol injection repeated 50 times during
  initial uranium remediation period (185-535
  days).
• Dissolved uranium concentrations (U(IV))
  monitored in injection and extraction wells as
  well as sampling well
• Oxidation state study of sediment samples with
  x-ray absorption spectroscopy to confirm
  reduction by microorganisms

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Area 3 Field Site Layout
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Results of Oakridge Study

• Initial Measurements
• Initial concentration of U(IV) prior to ethanol
  injection none
• Initial concentration of U(VI) in inner treatment
  zone 2uM
• Final Measurements
• Detection of U(IV) in inner zone injection well
  on day 258
• Detection of U(IV) in inner zone extraction well
  on day 535
• Final concentration of U(VI) in inner treatment
  zone lt1uM

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Future for Bioremediation?

• Pros
• Environmentally friendly
• Simple Process
• Inexpensive
• Cons
• Lacking knowledge
• Success dependent on site
• Difficult to extrapolate lab research to field

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Conclusions

• Uranium contamination is a serious problem and
  must be addressed to prevent further spread
• Conventional physical and chemical remediation
  methods are well-researched but can be costly and
  ineffective
• Bioremediation is a developing technology and
  further research is needed for effective use
• Potential to be a simpler, cheaper, and more
  environmentally friendly method of heavy metal
  remediation

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References

• 1. Abdel-Sabour, M.F. (2007). Remediation and
  Bioremediation of Uranium Contaminated Soils.
  Electronic Journal of Environmental, Agricultural
  and Food Chemistry, 6(5), 2009-2023.
• 2. Anderson, R., Vrionis, H., Ortiz-Bernad, I.,
  Resch, C., Long, P., Dayvault, R., et al.
  (2003). Stimulating the In Situ Activity of
  Geobacter Species To Remove Uranium from the
  Groundwater of a Uranium-Contaminated Aquifer.
  Applied and Environmental Microbiology, 69(10),
  5884-5891.
• 3. Beliaev, A.S., Thompson, D.K., Fields, M., Wu,
  L., Lies, D.P., Nealson, K.H., et al. (2002).
  Microarray Transcription Profiling of a
  Shewanella oneidensis etrA Mutant. Journal of
  Bacteriology, 184, 4612-4616.
• 4. Fomina, M., Charnock, J.M., Hillier, S.,
  Alvarez, R., Gadd, G.M. (2007). Fungal
  Transformations of Uranium Oxides. Environmental
  Microbiology, 9(7), 1696-1710.
• 5. Gavrilescu, M., Pavel, L., Cretescu, I.
  (2009). Characterization and Remediation of
  Soils Contaminated with Uranium. Journal of
  Hazardous Materials, 163(2-3), 475-510.
• 6. Ginder-Vogel, M., Wu, W., Carley, J., Jardine,
  P., Fendorf, S., Criddle, C. (2006). In Situ
  Biological Uranium Remediation within a Highly
  Contaminated Aquifer. Science Highlight.
• 7. Jardine, P.M., Watson, D.B., Blake, D.A.,
  Beard, L.P., Brooks, S.C., Carley, C.S., et al.
  (2004). Techniques for Assessing the Performance
  of In Situ Bioreduction and Immobilization of
  Metals and Radionuclides in Contaminated
  Subsurface Environments.
• 8. Kasama, T., Murakami T., Ohnuki, T. (2001).
  Accumulation Mechanisms of Uranium, Copper and
  Iron by Lichen Trapelia involuta.
• 9. Lovley, D.R. (2003). Cleaning Up with
  Genomics Applying Molecular Biology to
  Bioremediation. Nature Reviews Microbiology,
  1(October 2003), 35-44.
• 10. Pinchuk, G.E., Rodionov, D.A., Yang, C., Li,
  X., Osterman, A.L., Dervyn, E., et. al. (2009).
  Genomic Reconstruction of Shewanella oneidensis
  MR-1 Metabolism Reveals a Novel Machinery for
  Lactate Utilization. PNAS, 106(8), 2874-2879.
• 11. Todorov, P., Ilieva, E. (2006).
  Contamination with Uranium from Natural and
  Anthropological sources. Applied Physics.
  51(1-2). 27-34.

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• Questions???