03/03/2011
New Method for Uranium Remediation in Acidic Waste Plumes
Summary
Acidic uranium (U) groundwater plumes resulted from acid extraction of plutonium during the Cold War and from U mining and milling operations. A sustainable remediation method is not yet available. DOE scientists from Lawrence Berkeley National Laboratory are exploring the use of humic acids (HA) to immobilize U in groundwater under acidic conditions. When acidic groundwater (pH below 5.0) is treated with humic acid, U can adsorb onto aquifer sediments rapidly, strongly, and practically irreversibly. Using historically contaminated sediments from the DOE Savannah River site, column-leaching experiments show that with humic acid treatment, 99% of the contaminant U was immobilized at pH < 4.5 under normal groundwater flow rates, suggesting that humic acid treatment is a promising in situ remediation method for acidic U waste plumes. As a remediation reagent, humic acids are resistant to biodegradation, cost-effective, nontoxic, and easily introducible into the subsurface.
References
Wan, J., W. Dong, and T. K. Tokunaga. 2011. “Method To Attenuate U(VI) Mobility in Acidic Waste Plumes Using Humic Acids,” Environmental Science and Technology, 45(6), 2331–37. DOI: 10.1021/es103864t.