Measurement of natural radioactivity levels of major and heavy metals concentration was carried out for water samples collected from primary schools in Jeddah city, Saudi Arabia. The estimations were done for two different age groups, children (students 7 - 12 y) and adults (teachers and workers > 17 y) at the schools. The chemical analysis was performed by an Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and a high-resolution HPGe detector was used for the natural radionuclides measurement. The obtained results for the heavy metals (Fe, Cu, and Zn) and major and heavy elements (Na, K, Ca and Mg) concentrations in all water samples did not exceed the limits of WHO, EPA and TSE-266 guidelines for drinking water. Only Pb exceeded the safe limit. Generally, heavy metals and major elements’ concentrations in water samples were found decrease in sequence of Ca > Na > Mg > K > Zn > Pb > Cu > Fe. The radioactivity concentrations of 226Ra, 232Th and 40K in all studied samples were below the permissible safe limit value. The total average annual effective doses of (226Ra + 232Th + 40K) radionuclides were 0.259 mSv.y-1 for the children and 0.112 mSv.y-1 for adults, which are below the recommended annual dose level 1.0 mSv.y-1 as reported by WHO (2006). The present drinking waters are high quality waters and safe in terms of natural radioactivity and the results of the HQ values for the individual heavy metals showed that there was no health risk for humans due to consumption of these waters.
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