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Chemical Treatments of Soil to Decrease Radiostrontium Leachability
Author(s) -
Spalding Brian P.
Publication year - 1981
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1981.00472425001000010008x
Subject(s) - carbonate , leaching (pedology) , soil water , environmental chemistry , leachate , chemistry , groundwater , sodium carbonate , hydroxide , soil contamination , lessivage , fluoride , environmental science , geology , soil science , sodium , inorganic chemistry , geotechnical engineering , organic chemistry
The leachability of radiostrontium from radioactive waste and through soil is one of the most salient problems with shallow‐land burial as a disposal method. The continuous leaching of buried waste at the Oak Ridge National Laboratory (ORNL), for periods up to 30 years, by lateral ground water flow has led to the contamination of surrounding soils and streams with 90 Sr. The goal of the present investigation was to evaluate methods to effect either the in situ fixation or reduced leachability of 90 Sr in soil. Small columns of three soils, collected from the solid waste disposal areas at ORNL, were labeled with 85 Sr as a convenient tracer for 90 Sr. After this labeling, but prior to leaching, the soil columns were percolated with equivalent amounts of sodium salt solutions of hydroxide, fluoride, carbonate, phosphate, silicate, or aluminate. Leaching was then initiated with 0.1 N CaCl 2 which was selected to qualitatively simulate ground water which contains Ca as the dominant dissolved cation. With two soils, high in indigenous exchangeable Ca 2+ , only 30–35% of the 85 Sr could be leached from the carbonate‐treated columns. Presumably, the 85 Sr was coprecipitated with the nascent CaCO 3 formed during this treatment. In contrast, >98% of the 85 Sr was readily leached from all untreated soils. Other anions fixed variable but generally less 85 Sr than the carbonate treatment. Thus, sodium carbonate appears to have a potential application to immobilize 90 Sr in situ in contaminated soil.