MODIFIED BIOKINETIC MODEL FOR URANIUM FROM ANALYSIS OF ACUTE EXPOSURE TO UF6

Urinalysis measurements from 31 workers acutely exposed to uranium hexafluoride (UF6) and its hydrolysis product UO2F2 (during the 1986 Gore, Oklahoma UF6-release accident) were used to develop a modified recycling biokinetic model for soluble U compounds. The model is expressed as a five-compartment exponential equation: y(u)(t) = 0.86e-2.77t + 0.0048e-0.116t + 0.00069e-0.0267t + 0.00017e-0.00231t + 2.5 x 10(-6)e-0.000187t, where y(u)(t) is the fractional daily urinary excretion and t is the time after intake, in days. The excretion constants of the five exponential compartments correspond to residence half-times of 0.25, 6, 26, 300, and 3,700 d in the lungs, kidneys, other soft tissues, and in two bone volume compartments, respectively. The modified recycling model was used to estimate intake amounts, the resulting committed effective dose equivalent, maximum kidney concentrations, and dose equivalent to bone surfaces, kidneys, and lungs.