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Reduction of Radiostrontium Mobility in Acid Soils by Carbonate Treatment
Author(s) -
Browman M. G.,
Spalding B. P.
Publication year - 1984
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/jeq1984.00472425001300010031x
Subject(s) - carbonate , chemistry , leaching (pedology) , soil water , organic matter , alkalinity , environmental chemistry , dissolution , cation exchange capacity , ion exchange , precipitation , calcium carbonate , radiochemistry , nuclear chemistry , soil science , geology , ion , physics , organic chemistry , meteorology
Abstract Development of chemical treatments to immobilize 90 Sr in soil to prevent its leaching from radioactive waste disposed in shallow land burial sites is highly desirable. Six in situ carbonate‐precipitating treatments, varying the amounts of carbonate, alkaline earth cation (Ca or Ba as chlorides), and order of addition were examined for their ability to immobilize radiostrontium in laboratory soil columns. The Na 2 CO 3 ‐followed by CaCl 2 ‐treatment was most consistently successful at reducing the teachability of radiostrontium by 0.05 M CaCl 2 from three low organic matter‐acid soils, immobilizing as much as 53% of added radiostrontium. For the high organic matter‐slightly acid soil, Na 2 CO 3 alone, without supplemental Ca or Ba, resulted in the best immobilization (39%); dissolution of soil organic matter and the alkalinity‐induced aggregate dispersion probably interfered with CaCO 3 and/or BaCO 3 precipitation. Success of the treatments is based primarily on their ability to generate, in situ, Ca(Sr,Mg)CO 3 or Ba(Ca,Mg,Sr)CO 3 precipitates that exchange radiostrontium very slowly with eluting Ca ions. Allied tests with 137 Cs, which is commonly codisposed with 90 Sr, indicated that the treatments described did not interfere with the natural tendency of the selected soils to fix 137 Cs strongly.