Radiation hazards from 226 Ra, 232 Th and 40 K content in drinking waters of Islamabad, Pakistan

This paper reports concentrations of 226Ra, 232Th and 40K in drinking waters from Islamabad, Pakistan. The aim is to estimate the radiological hazard risk and assess the radiation safety due to drinking water use. Radiation hazard indices and excess lifetime cancer risks are reported from all measurements. Different drinking water samples have been collected from Islamabad (33° 38'N, 73° 09'E) and analysed using a high purity germanium detector (HPGe). The average concentration values of 226Ra, 232Th and 40K were 6 ± 0.6, 32 ± 1 and 74 ± 2 Bq L-1, respectively. The radium equivalent activity was 58 Bq L-1, the outdoor external dose was 0.2 nGy/h, the indoor external dose was 46 nGy/h and the total average annual dose was 0.2 nGy/h. The excess lifetime cancer risk was equal to 0.8 × 10-3. All reported values are lower than the globally calculated values and within recommended limits.