Phytoremediation of Uranium-Contaminated Soils:  Role of Organic Acids in Triggering Uranium Hyperaccumulation in Plants

• Published in: Environmental science & technology Vol. 32; no. 13; pp. 2004 - 2008
• Main Authors: Huang, Jianwei W, Blaylock, Michael J, Kapulnik, Yoram, Ensley, Burt D
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-07-1998
• Subjects: Acids; Applied sciences; BIODECONTAMINACION; Biodegradation of pollutants; Biological and medical sciences; BIOREMEDIATION; Biotechnology; Contamination; Decontamination. Miscellaneous; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environment and pollution; Exact sciences and technology; Flowers & plants; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; POLLUTED SOIL; Pollution; Pollution, environment geology; Soil and sediments pollution; Soil contamination; Soils; SOL POLLUE; SUELO CONTAMINADO; Uranium; Ohio; United States; North America; America; Radioactive pollution; In situ; Vegetation effect; Soil pollution; Organic acids; Phytoremediation; Actinide; Additive; Amendment; Plant; Uranium; Decontamination; Biological accumulation
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es971027u

Uranium phytoextraction, the use of plants to extract U from contaminated soils, is an emerging technology. We report on the development of this technology for the cleanup of U-contaminated soils. In this research, we investigated the effects of various soil amendments on U desorption from soil to soil solution, studied the physi ological characteristics of U uptake and accumulation in plants, and developed techniques to trigger U hyperac cumulation in plants. A key to the success of U phytoextraction is to increase soil U availability to plants. We have found that some organic acids can be added to soils to increase U desorption from soil to soil solution and to trigger a rapid U accumulation in plants. Of the organic acids (acetic acid, citric acid, and malic acid) tested, citric acid was the most effective in enhancing U accumulation in plants. Shoot U concentrations of Brassica juncea and Brassica chinensis grown in a U-contaminated soil (total soil U, 750 mg kg-1) increased from less than 5 mg kg-1 to more than 5000 mg kg-1 in citric acid-treated soils. To our knowledge, this is the highest shoot U concentration reported for plants grown on U-contaminated soils. Using this U hyperaccumulation technique, we are now able to increase U accumulation in shoots of selected plant species grown in two U-contaminated soils (total soil U, 280 and 750 mg kg-1) by more than 1000-fold within a few days. Our results suggest that U phytoextraction may provide an environmentally friendly alternative for the cleanup of U-contaminated soils.