Leachability of radium from fertilizer and monazite process wastes

Leaching studies on the fertilizer and monazite process waste sludges have indicated that a significant fraction of radium is in a loosely bound state. The study indicates that there is a significant potential for 226Ra contamination of the environment owing to the processing of phosphate rock for the production of fertilizer and the disposal of phosphogypsum. Even though this aspect has been recognized, its wider implications have not been fully evaluated. Data on the leachability aspects of the phosphate sludge are available only from one study, reported above. Further data are required on the 226Ra content of phosphogypsum from different sources, leachability, physico-chemical forms, dispersal, migration and biological uptake. Information on other radionuclides that may be present in the sludge also need detailed study. The problems associated with monazite waste sludge disposal have also not been fully understood. Published information is very limited in this area. Monazite waste sludge, having a much higher specific activity as compared with uranium mill tailings or phosphogypsum, has the potential of causing a higher degree of localized environmental contamination if adequate precautions are not taken during its disposal. 24 refs, 2 figs, 6 tabs