Assessing the applicability of a special model of plutonium behavior in presence of chelates in cases of wound intake of industrial compounds of plutonium in the FSUE Mayak PA workers

Abstract

In cases of intake of higher levels of plutonium, a chelate diethylenetriaminepentaacetic acid is used to enhance the elimination and reduce deposition rate in the organs of major deposit in the form of calcium compound Ca-DTPA (pentacinum). To interpret the results of the nuclide measurements in excreta while estimating the doses of internal exposure to plutonium, the biokinetic and dosimetry models recommended by ICRP are applied; and in case of the actinide intake through damaged skin it is recommended to use the models of NCRP of the USA. Since the application of chelates significantly changes the picture of plutonium urinary excretion, special models of complex Pu-DTPA behavior are developed to describe the plutonium biokinetics in presence of chelates. The purpose of this work is to assess the suitability of a special model of plutonium behavior in presence of chelates elaborated by K. Konzen to describe the plutonium biokinetics in the body by the cases of wound intake of industrial plutonium compounds in the FSUE Mayak PA workers. This study used the measurements of plutonium activity in daily amount of urine for three cases with the actinide intake through damaged skin and Ca-DTPA treatment, the duration of pentacinum application and observation periods for workers depending on the levels of intake. For each case, the most likely type of an entered compound was selected using Akaike information criterion, then the daily urinary activity of plutonium was calculated by the model (estimated value) on the same days when it was determined actually (actual values). The analysis of the compliance of calculated data with actual data was conducted using the statistic tests of Foster-Stewart,Breusch-Godfrey, Mann-Whitney, Shapiro-Wilk, and the determination coefficient. It was found that for all cases considered, the adjusted determination coefficient and Foster-Stewart test indicated the compliance of actual data with calculated ones. The statistical analysis of the compliance of calculated data with actual measurements of plutonium urinary activity showed that the special model of plutonium behavior proposed by K. Konzen was able to predict the urinary activity of plutonium during both the radionuclide decorporation measures and the period of pentacinum aftereffect.