Variation of solubility,biokinetics and dose coefficient of industrial uranium oxides according to specific surface area
Chazel, V.; Houpert, P.; Ansorbolo, E.; Henge-Napoli, M.H.; Paquet, F
Radiation Prot. Dos. 2000, vol 88 n°3, 223-231
The in vitro solubility, absorption to blood, lung retention and dose coefficient of industrial UO2 samples were studied as a function of the specific surface area (SSA) of the particles. An in vitro study has been carried out on two samples of industrial UO4 to compare the results to those obtained with UO2. Ten UO2 samples supplied by different fuel factories or research laboratories presented specific surface areas from 1.00 to 4.45 m2/g. The wide range of values of SSA was due to the different conditions of fabrication. Dissolution tests in cell culture medium made on these 10 samples have shown that the solubility increaser 2.5-fold when the SSA increased 1.7-fold. The same tendancy has been found for UO4, a soluble compound, and for U3O8, a moderately soluble compound. Four in vivo experiments carried out on rats by intratracheal instillation of dust suspensions of UO2 have highlighted the decrease in lung retention and the increase of absorption to blood with the SSA.
The experimental absorption parameters calculated from the in vivo data allowed specific dose coefficients to be obtained which decreased from 6.6 to 4.3 µSv/Bq when the SSA increased from 1.60 to 3.08 m2/g. Thus, yhe medical monitoring of workers at the workplace has to take into account any change in the fabrication process of the uranium compound which can affect the physicochemical properties and consequently the dose coefficient.