Phytoextraction for clean-up of low-level uranium contaminated soil evaluated.
Spills in the nuclear fuel cycle have led to soil contamination with uranium. In case of small contamination just above release levels, low-cost yet sufficiently efficient remedial measures are recommended. This study was executed to test if low-level U contaminated sandy soil from a nuclear fuel processing site could be phytoextracted in order to attain the required release limits. Two soils were tested: a control soil (317 Bq 238U kg(-1)) and the same soil washed with bicarbonate (69 Bq 238U kg(-1)). Ryegrass (Lolium perenne cv. Melvina) and Indian mustard (Brassica juncea cv. Vitasso) were used as test plants. The annual removal of soil activity by the biomass was less than 0.1%. The addition of citric acid (25 mmol kg(-1)) 1 week before the harvest increased U uptake up to 500-fold. With a ryegrass and mustard yield of 15,000 and 10,000 kg ha(-1), respectively, up to 3.5% and 4.6% of the soil activity could be removed annually by the biomass. With a desired activity reduction level of 1.5 and 5 for the bicarbonate-washed and control soil, respectively, it would take 10-50 years to attain the release limit. However, citric acid addition resulted in a decreased dry weight production.
Vandenhove
H
H
Belgian Nuclear Research Centre, SCK-CEN, Radioecology Section, Radiation Protection Department, Boeretang 200, B-2400 Mol, Belgium. hvandenh@sckcen.be
Van Hees
M
M
D001673:Biodegradation, Environmental; D018533:Biomass; D001937:Brassica / Q000737:chemistry* / Q000254:growth & development; D008129:Lolium / Q000737:chemistry* / Q000254:growth & development; D011210:Power Plants; D018788:Radioactive Hazard Release; D012822:Silicon Dioxide; D012990:Soil Pollutants, Radioactive / Q000302:isolation & purification*; D014501:Uranium / Q000302:isolation & purification*
D012990:Soil Pollutants, Radioactive; D014501:Uranium; D012822:Silicon Dioxide