CHEMICAL TRANSFORMATION OF URANIUM TETROXIDE PARTICLES IN RAT LUNGS AFTER INTRATRACHEAL DEPOSIT

A specific uranium oxide compound (UO4) which is encountered in the fu el cycle fabrication has been studied after intratracheal instillation in rats. The transformation of the particles has been observed by tra nsmission electron microscopy and analyzed by electron energy loss spe ctrometry and X-ray spectrometry. The transformation of the particles occurred very quickly after instillation: after 24 h, some uranium nee dles, identified as uranyl phosphates, were already observed within ly sosomes. At the same time, UO4 particles could be observed being fragm ented in very tiny chips within the phagosomes. These results enhance importance of the early dissolution phenomenon occurring in the lung a fter particle inhalation. They underline the validity of the absorptio n parameters defined by the ICRP in the publication 66 [11] describing the human respiratory tract model.