URANIUM CASES SHOWING LONG CHEST BURDEN RETENTION - AN UPDATING

Routine uranium in vivo, urine and fecal measurements have been continued on four employees previously reported as having unusually long retention of uranium chest burdens. Data have been obtained for a period of 3,5 yr since that report. The data including this period are compared to those previously obtained, and the cases are reassessed on the basis of these additional data. It was found that the half life of uranium in the chest, as measured by in vivo monitoring of these employees, is not statistically different from that previously reported. The urine to fecal elimination rate ratio on these employees averaged about 1, indicating fecal excretion to be an important mode of lung clearance. Efforts to better determine the nature and causes of these exposures by the selection of the most likely exposure material(s) and conduction of animal inhalation experiments are outlined. These efforts have not been successful in establishing a complete understanding of the reason(s) for the unusual retention patterns exhibited by these persons. © 1969 Health Physics Society.