Risk assessment due to ingestion of natural radionuclides and heavy metals in drinking water

The concentrations of natural radioactivity of 226Ra, 232Th and 40K and some heavy elements (Zn, Mn, Fe, Mn, Cu, Ni, and Pb) were measured in drinking water samples collected from different mosques in Makkah city, Saudi Arabia. A high-resolution HPGe detector was used for the natural radionuclides measurement. The average activity concentrations were 0.32, 0.12 and 10.96 Bql− 1 for 226Ra, 232Th, and 40 K, respectively. The cumulative annual effective dose due to ingestion of water samples was estimated to be 0.832 μSv y−1 for children and 0.369 μSv y−1for adults, which are below the limit of 1.0 mSv y-1 for individual public exposure. These water samples were also analyzed for concentration of some heavy elements (Fe, Zn, Cu, Mn, Ni and Pb) using the inductively coupled plasma optical emission spectrophotometer (ICP-OES).The obtained results established that the heavy elements concentration in the drinking water samples did not exceed the recommended limits WHO and EPA guidelines for drinking water