Activities of the department of radiation control at the Regional Health Inspectorate - Ruse during and after two accidents in NPP

The purpose of this work is to compare the indicators and results from the analysis of samples used for the environmental monitoring by the Department of Radiation control in Ruse during the nuclear accidents at Chernobyl Nuclear Power Plant (1986) and Fukushima Nuclear Power Plant (2011). 120 samples (food, drinking water, vegetation, soil, water from the Danube, bottom sediments, atmospheric deposition and air) from six districts in North-Eastern Bulgaria were analyzed. Parameters measured were total-beta activity, Cs-137, Sr-90, Ra-226, U-235, at a later stage - K-40, Pb-214 and others. The results were compared with the levels in the existing regulations and with the background levels. Measured values of technogenic radionuclides were increased in all samples taken after the accident at Chernobyl NPP. After three months the measured values were still high with trending to decrease. One year after the accident at Chernobyl NPP a significant decrease has been already seen in atmospheric deposition approaching the normal range. In food samples high level of activity of Cs-137, Sr-90 and total-beta activity were observed, resulting from the use of contaminated feed.In samples analyzed after the Fukushima NPP no increase was found above the background values. After the nuclear accident at Chernobyl NPP increased values of radionuclides in the samples analyzed were found compared to the reference levels in the regulation. For samples after the accident at the Fukushima NPP no increase was detected. The results show the role of health-radiation control during emergencies - rapid detection of high levels of radionuclides in products directly related to public health. (authors)