The results
of 222Rn and 226Ra activity measurements in drinkable water supplies of the ThuDuc region
in HoChiMinh City,Vietnam,are presented in this paper.The measurements were performed using a
RAD 7 radon detector manufactured by Durridge Company,Inc.Mean concentrations of 222Rn and 226Ra
were found to be 0.1170.01 Bql1 and 0.1170.02 Bql1 in 14 drinking water samples.They are
0.1270.01Bql1 and 0.1070.02 Bql1 in 15 tap water samples,respectively