PNNL

Abstract

Seven groups of 8-24 beagle dogs, exposed to 239PuO2 aerosols by inhalation (mean initial lung depositions of 0.0, 0.14, 0.63, 3.2, 13, 44, and 210 kBq), were observed throughout their lives to determine tissues at risk and intake-effect relationships. The mean average pulmonary retention half-time of 239Pu was 1192 days. Most (70%) of the plutonium recovered at death in dogs surviving >10 years after exposure was found in the thoracic lymph nodes with 15% in lung, ~10% in liver and 2% in bone. Eight dogs at the highest exposure levels died from radiation pneumonitis prior to a minimal 3-year latency period after exposure for the observation of lung tumors, with the first succumbing 337 days after exposure. Of 108 plutonium-exposed beagles with ILD