THE DEVELOPMENT OF THE PLUTONIUM LUNG CLEARANCE MODEL FOR EXPOSURE ESTIMATION OF THE MAYAK PRODUCTION ASSOCIATION, NUCLEAR PLANT WORKERS

The purpose of this study was to develop a biokinetic model that uses urinary plutonium excretion rate data to estimate the plutonium accumulation in the human respiratory tract after occupational exposure. The model is based on autopsy and urinalysis data, specifically the plutonium distribution between the respiratory tract and the remainder of the body, taken from 543 former workers of a radiochemical facility at the Mayak Production Association (MPA) plant. The metabolism of plutonium was represented with a compartmental model, which considers individual exposure histories and the inherent solubility properties of industrial plutonium aerosols. The transport properties of plutonium-containing aerosols were estimated by experimentally defining their in vitro solubility. The in vitro solubilities were found by dialysis in a Ringer’s solution. Analysis of the autopsy data indicated that a considerable fraction of the inhaled plutonium is systemically redistributed rapidly after inhalation. After the initial dynamic period, a three-compartment model describes the retention in the respiratory tract. One compartment describes the nuclide retained in the lungs, the second compartment describes a plutonium lung concentration that exponentially decreases with time, and the third compartment describes the concentration in the pulmonary lymph nodes. The model parameters were estimated by minimizing sum squared of the error between the tissue and bioassay data and the model results. The parameters reflect the inverse relationship between plutonium retention in lungs and the experimentally derived aerosol transportability. The model was validated by comparing the autopsy results with in vivo data for 347 cases. The validation indicates that the model parameters are unbiased. This model is being used to estimate individual levels of nuclide accumulation and to compute radiation doses based upon the urinary excretion rates.

[1]  S. Miller,et al.  Development of an improved dosimetry system for the workers at the Mayak Production Association. , 2000, Health physics.

[2]  V. Khokhryakov,et al.  A scintillation method for determination of actinide alpha-activity in samples , 1998 .

[3]  V. Khokhryakov,et al.  Classification of alpha-active workplace aerosols based on coefficient of transportability as measured by the dialysis method , 1998 .

[4]  R. Kathren,et al.  Comparison of the Dosimetry Registry of the Mayak Industrial Association and the United States Transuranium and Uranium Registries: A Preliminary Report , 1996 .

[5]  W. J. Bair,et al.  The ICRP Human Respiratory Tract Model for Radiological Protection , 1995 .

[6]  V. Khokhryakov,et al.  Plutonium Excretion Model for the Healthy Man , 1994 .

[7]  A. Hickman,et al.  Intake Assessment for Workers Who Have Inhaled 238Pu Aerosols , 1994 .

[8]  M. J. Sula,et al.  Long-Term Follow-up of HAN-1, an Acute Plutonium Oxide Inhalation Case , 1991 .

[9]  J. A. Mewhinney,et al.  Biokinetics of inhaled 239PuO2 in the beagle dog: effect of aerosol particle size. , 1984, International journal of radiation biology and related studies in physics, chemistry, and medicine.

[10]  Diel Jh,et al.  Retention of inhaled 238PuO2 in beagles: a mechanistic approach to description. , 1983 .

[11]  W. C. Cannon,et al.  Comparative disposition of inhaled 238Pu and 239Pu nitrates in beagles. , 1983, Health physics.

[12]  B. T. Taylor,et al.  Differential clearance of plutonium and americium oxides from the human lung. , 1983, Health physics.

[13]  J. A. Mewhinney,et al.  Retention of inhaled 238PuO2 in beagles: a mechanistic approach to description. , 1983, Health physics.

[14]  G J Ham,et al.  The biological solubility in the rat of plutonium present in mixed plutonium--sodium aerosols. , 1978, Health physics.

[15]  G. Ham,et al.  The in vivo solubility of plutonium-239 dioxide in the rat lung. , 1977, Health physics.

[16]  J. Rundo,et al.  Excretion rate and retention of plutonium 10,000 days after acquisition , 1975 .

[17]  D. C. Fraser,et al.  In-vivo and bioassay results from two contrasting cases of plutonium-239 inhalation. , 1970, Health physics.

[18]  J. R. Mann,et al.  Evaluation of accidental personnel exposure to plutonium-238: whole body counting and bioassay results. , 1970, Health physics.

[19]  W. J. Bair,et al.  Retention, translocation and excretion of inhaled Pu-239-O-2. , 1962, Health physics.

[20]  J. Lenihan.  Recommendations of the International Commission on Radiological Protection: Report of Committee II on Permissible Dose for Internal Radiation , 1960 .