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Interactions among phosphate amendments, microbes and uranium mobility in contaminated sediments
Anna Sophia Knox1, R L Brigmon, D I Kaplan
1Savannah River National Laboratory, Aiken, SC 29808, USA. anna.knox@srnl.doe.gov
The Science of the Total Environment
|April 1, 2008
Summary
Phosphate amendments effectively immobilize uranium in contaminated soils. However, microbial activity can significantly reduce this effectiveness, impacting environmental cleanup strategies for radionuclides.
Area of Science:
- Environmental Science
- Geochemistry
- Microbiology
Background:
- Radionuclide contamination in soils and sediments poses environmental risks.
- Sequestering agents offer potential for environmental remediation.
- Understanding uranium (U) mobility is crucial for effective cleanup.
Purpose of the Study:
- To evaluate the impact of phosphate amendments and microbial activity on uranium mobility in contaminated sediments.
- To compare the effectiveness of different phosphate sources and microbial species.
Main Methods:
- Tested three phosphate amendments (rock phosphate, biological phosphate, calcium phytate) and two microbial amendments (Alcaligenes piechaudii, Pseudomonas putida).
- Assessed uranium concentrations in aqueous solutions and 1 M MgCl(2) extracts from contaminated sediments.
- Compared results from live and autoclaved (microbe-inactivated) sediment treatments.
Main Results:
- Phosphate amendments reduced aqueous U concentrations by over 90%.
- Microbial amendments alone reduced U concentrations by 63% (A. piechaudii) and 31% (P. putida).
- Microbial activity significantly decreased the effectiveness of phosphate amendments in reducing U concentrations.
Conclusions:
- Phosphate amendments are effective in immobilizing uranium.
- Microbial activity in sediments can interfere with the remedial effectiveness of phosphate amendments.
- Further research is needed to optimize combined bioremediation and chemical treatment strategies.
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