Water from bedrock frequently contains higher concentrations of natural radionuclides than water from other 22
sources. Groundwater from Assalamia-Alhomira and Juban areas (southeast of Sana'a) and hot spring water 23
from Dempt area (south Sana'a) in Yemen were analyzed for 226Ra, 232Th and 40 K activity concentrations. 24
The average activity concentrations for groundwater from Assalamia–Alhomira area were 4.04 Bql−1 and 25
1.81 Bql−1 for 226Ra and 232Th, respectively, while 40 K was not detectable, while that for groundwater sam- 26
ples from Juban area were 2.95 Bql−1, 0.72 Bql−1 and 34.9 Bql−1 for 226Ra, 232Th and 40 K, respectively. On 27
the other hand, the activity concentrations for hot spring water from Dempt area were 3.48 Bql−1, 1.01 28
Bql−1 and 16.05 Bql−1 for 226Ra, 232Th and 40K, respectively. Also annual effective dose equivalent of ingestion 29
of these waters was calculated. The results showed that the annual dose equivalent obtained in the present 30
study was much higher than the recommended value (0.1 mSv year−1) as reported by WHO. The results 31
were compared with those for drinking water.