The alpha spectrometry measurements of specific activity of 238Pu and 239Pu in urine from bioassay examinations of 1,013 workers employed at the radiochemical and plutonium production facilities of the Mayak Production Association and in autopsy specimens of lung, liver, and skeleton from 85 former nuclear workers who died between 1974–2009, are summarized. The accumulation fraction of 238Pu in the body and excreta has not changed with time in workers involved in production of weapons-grade plutonium production (e.g., the plutonium production facility and the former radiochemical facility). The accumulation fraction of 238Pu in individuals exposed to plutonium isotopes at the newer Spent Nuclear Fuel Reprocessing Plant ranged from 0.13% up to 27.5% based on the autopsy data. No statistically significant differences between 238Pu and 239Pu in distribution by the main organs of plutonium deposition were found in the Mayak workers. Based on the bioassay data, the fraction of 238Pu activity in urine is on average 38–69% of the total activity of 238Pu and 239Pu, which correlates with the isotopic composition in workplace air sampled at the Spent Nuclear Fuel Reprocessing Plant. In view of the higher specific activity of 238Pu, the contribution of 238Pu to the total internal dose, particularly in the skeleton and liver, might be expected to continue to increase, and continued surveillance is recommended.
*Southern Urals Biophysics Institute (SUBI), Ozyorsk, Chelyabinsk Region, Russia; †Radiobiology Division, School of Medicine, University of Utah, Salt Lake City, UT.
This study was managed by the Joint Coordinating Committee for Radiation Effects Research (JCCRER) and supported by funding from the United States Department of Energy and the Federal Medical-Biological Agency (FMBA) of the Russian Federation.
For correspondence contact: Klara Suslova, Southern Urals Biophysics Institute (SUBI), Ozyorskoe Shosse 19, Ozyorsk, Chelyabinsk Region, 456780 Russia, or email at firstname.lastname@example.org.
(Manuscript accepted 24 August 2011)