In Vitro Dissolution Rates of Radionuclides in Aerosol Particles from the Florida Phosphate Industry

K.P. Kim¹; W.E. Bolch¹; C.Y. Wu¹; and B.K. Birky² (¹University of Florida; ²Florida Institute of Phosphate Research)

Phosphate ores from central Florida contain relatively high concentrations of radionuclides from the uranium decay series. Chronic inhalation of these particles during phosphate ore processing is thus a potential concern to workers. Of the many particle properties that may influence individualized estimates of lung and effective dose, particle solubility in the lung fluids is perhaps the most important. The lung solubility of radionuclides contained within the aerosol particles depends on the particle matrix. In this study, the dissolution rate of aerosol particles from the Florida phosphate industry was determined using a simulated lung fluid and the batch dissolution method. The amount of dissolved phosphate material and radionuclide activity were measured periodically via ion chromatography, uranium fluorescence, and gamma-ray spectroscopy. Fast and slow dissolution fractions and dissolution rates based on ICRP 66 dosimetry model were determined for several facilities in the Florida phosphate industry. *Work supported by Grant FIPR #03-05-064 from the Florida Institute of Phosphate Research with the University of Florida.

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