Artificial radionuclide concentrations in the Bulgarian population over the period 1986-1988: An assessment of the irradiation of the Bulgarian population as a result of the global radioactive contamination of the country after 1 May 1986

During the time of radioactive contamination of the Bulgarian territory due to the Chernobyl accident after 1 May 1986 groups of the population were examined for determination of artificial radionuclide concentrations in the body. From 1 May to 15 June tests were done on about 6000 people, both male and female, of different ages and from different regions of the country to measure the concentrations of 131I in the thyroid glands. The highest concentrations were observed in the period 20-30 May. The highest mean values were observed to be about 300 Bq, although in some people levels of the order of 6000 Bq were detected. Between 1986 and 1988 about 4000 people were examined for artificial radionuclides with fixed and portable whole body counters. During May-July 1986 about 15 artificial radionuclides were found. After the summer of 1986 mainly 137Cs and 134Cs were detected. Their concentrations gradually increased and reached a maximum in April 1987 for 137Cs and in January 1987 for 134Cs. Then they gradually decreased. It was found that the concentrations of both radionuclides in the body depend on the age, sex, physiological characteristics and diet of the individual and on their concentration in food, which was quite different for the different regions of the country. The highest concentrations were detected in people living in southern Bulgaria - these reached 300 Bq/kg (total for 134Cs and 137Cs). (author). 4 figs, 1 tab