Radiological Monitoring of Waters in Bulgaria

The radiological indicators of drinking and groundwaters from different regions ofBulgaria were tested and analyzed in 2024 in connection with the regular monitoring ofwaters in Bulgaria. Higher uranium content than the norm regulated in the national legislationwas found in separate samples from the districts of Burgas, Plovdiv, and Smolyan.Increased alpha activity was determined in drinking and groundwaters from thedistricts of Burgas, Pernik, Yambol, Plovdiv, Haskovo, and Smolyan. This is probably due toboth the specific hydro-geological structure of the aquifers and the presence of sites related tothe underground uranium mining carried out in the past in the country. The analysis foundthat in most cases the higher alpha activity is due to the contribution of uranium, whichexhibits low radiotoxicity and after calculating the indicative dose, which did not exceed 0.1mSv per year, the waters were determined as safe for consumption from radiological point ofview. In cases where uranium concentration in the studied samples was not sufficient tojustify the higher alpha activity, the waters were analyzed for the presence of polonium-210,due to the high radiotoxicity of the radionuclide. Only in one of the waters from the Smolyanregion, it was higher than the secondary concentration determined in the regulations, which isprobably due to the fact that the water was from a new drilling and contained sedimentparticles, since polonium-210 usually settles in sediments.In general, the monitoring of waters from different regions of Bulgaria carried out in2024 found that in the majority of the samples the radiological indicators did not exceed theparametric values set out in the national legislation