The natural radioactivity in drinking water by gross alpha and beta measurements and radiological quality assessment

The aim of this study is to investigate the radiological quality of drinking waters consumed in Nevsehir province which is the most important tourism destination of the Cappadocia region. The activity concentration of gross alpha- and beta-emitting from natural radionuclides (U-238, U-234, Th-230 , Ra-226, Po-210, Th-232 and Pb-210, Ra-228 and K-40) in 21 tap water samples supplied by municipal pipelines were analyzed by using a gas proportional alpha/beta counter. The average activity concentrations of the gross alpha and gross beta in tap water samples were found as 88 +/- 10 mBq L-1 and 305 +/- 32 mBq L-1, respectively. The average natural activity concentrations of alpha- and beta-emitting radionuclides in tap water samples are below the limit values recommended by the Turkish regulation and WHO. For all samples, except for one sample, the gross beta activity concentrations are higher than the corresponding gross alpha concentrations. The average annual effective radiation dose (AERD) due to the ingestion of these water samples was estimated to be 43, 60 and 124 mu Sv year(-1) for infants, children, and adults, respectively. The average of AERD estimated for adults is 24% higher than the dose limit of 100 mu Sv year(-1). The activity concentration results reveal that tap water samples are acceptable for human consumption in accordance with the Turkish regulation and WHO recommendations for drinking water.