Cellular aspects of retention and transport of inhaled soluble and insoluble actinide compounds in the rat lung

Uranium carcinogenicity in humans might depend on the physical and chemical nature of uranium and its isotopic composition: results from pilot epidemiological study of French nuclear workers

“…Depending on solubility and radioactivity, inhaled particles emitting alpha radiation may cause severe biological damage to the surrounding cells, which may play a role in one or more stages of carcinogenesis. In the case of exposure to insoluble particles of enriched uranium or plutonium, the lung and lymph nodes associated with lymphatic drainage of the respiratory tract receive the highest dose of alpha radiation, followed by bone, soft tissue and kidney [55,[58][59][60]. Our reprocessed uranium results showing a stronger effect of this exposure on lung and lymphatic cancer mortality are consistent with these data.…”

“…Insoluble UO 2 and PuO 2 particles remain within the lysosomes of macrophages and may damage the lysosomal membranes. The particles can thus also be observed free in the cytoplasm [54,55]. Experimental animal studies have shown that insoluble actinide particles are retained in the lung and lymph nodes for a long time.…”

Biokinetics of nuclear fuel compounds and biological effects of nonuniform radiation.

“…The values for other organs and tissues were below 0.1%. Similar observations have been made with mixed (U,Pu)02 particles (87). Only 1% of the initial alveolar deposit was found in the rat liver, spleen, or kidneys throughout the 200-day observation period.…”

“…Current studies reveal that the clearance half-time from the rat lung is 247 days for U02 particles with an aerodynamic diameter of 2.7-3.2 pm after a single exposure (103). Mixed (U,Pu)02 particles appear to have a shorter biological halftime in the rat lung compared to U02 particles but similar to PuO2 particles (91,92,104,105) ranging from 60 to 100 days (87,102). The retention of these mixed oxide aerosols is not significantly influenced by particle shape or exposure method.…”

“…Insoluble U02 and PuO2 partides remain within the lysosomes of alveolar macrophages and may damage the lysosomal membranes. The particles can thus also be observed free in the cytoplasm (87). Leach et al (89,90) exposed dogs, monkeys, and rats in a 5-year inhalation study to a natural uranium dioxide (UO2) aerosol of approximately 1 pm mass median diameter at a mean concentration of 5 mg/m3.…”