INVESTIGATION OF NATURAL RADIOACTIVITY OF MINERAL WATERS IN SOUTHERN BULGARIA

Abstract

The activity of naturally occurring radionuclides in mineral waters from certain most frequently used sources in Rhodope Mountains region, Southern Bulgaria has been measured with high precision by means of nuclear and radiochemical methods. The survey is pointed at radium-226 (226Ra), lead-210 (210Pb) and natural uranium (nat. U), which are most important from the point of view of public health in Bulgaria, because of their high toxicity and radiotoxicity in drinking water. Seventeen water sources were under investigation. The activity concentrations of 226Ra and 210Pb varied from 13 to168 mBq/L and from ≤ 1.8 to 104 mBq/L respectively. The concentration of nat. U in the mineral water was in the range ≤ 3 to 21 µg/L. The annual effective doses were calculated for all investigated waters for adult inhabitants assuming yearly consumption of 730 litres. The results have shown that all values of the annual effective dose of ingestion of mineral waters were below the individual dose criterion of 100 µSv/y reported by World Health Organization (WHO). The obtained new results are used to assess the radiation status of the investigated waters. They will support timely and adequate measures to reduce the harmful impact of ionizing radiation on the population in cases of increased radioactivity