MORTALITY FROM MALIGNANCIES OF THE HEMATOPOIETIC AND LYMPHATIC TISSUES AMONG PERSONNEL OF THE 1ST NUCLEAR-PLANT IN THE USSR

This paper reports results from the study of mortality from malignanci es of the hematopoietic and lymphatic system among personnel of the fi rst nuclear reactor and processing plant in the USSR. Two registers ha ve been set up. They include all personnel of the atomic reactor (regi ster A) and of the radiochemical processing plant (register B). The op eration of these installations started in 1948, and two cohorts were f ormed; cohort I includes those who started employment between 1948 and 1953, cohort II those who started employment from 1954 to 1958. The p redominant contribution to the occupational exposure was from external gamma-radiation. Adverse radiation situations prevailed during the fi rst years at both facilities, and this resulted in substantial exposur es of the personnel. Significant increases of the total cancer mortali ty rates and the proportion of malignancies of the haematopoietic and the lymphatic system were seen in the internal comparison only in coho rt I of male workers from facility B. In the same cohort there was a s tatistically significant excess of the standardized mortality rates fr om malignancies of the haematopoietic and the lymphatic system over th e population rates in the Soviet Union. Our estimate for the excess re lative leukemia risk is 1.45/Gy, which is 2.7 times less than the rela tive excess risk of 3.92/Gy that was observed for the A-bomb survivors over age 20 ATB (Shimizu et al. 1987).