Assessment of Radiological Hazard of Natural Radioactivity in Drinking Water in Ondo, Nigeria

The paper determines the natural activity concentrations of 226Ra, 232Th and 40K in water samples from various ponds and rivers in some parts of Ondo State, Nigeria. The measurement was done by gamma-ray spectrometry system with high-purity germanium detector. The activity concentrations in ponds for 226Ra, 232Th and 40K varied from (0.15±0.01 to 0.82±0.04 Bq/l), (0.52±0.10 to 1.64±0.20 Bq/l) and (0.25±0.05 to 3.60±0.21 Bq/l) respectively and the activity concentration in rivers varied from (0.17±0.01 to 0.23±0.04 Bq/l), (0.56±0.02 to 1.38±0.20 Bq/l) and (0.46±0.02 to 5.38±0.10 Bq/l) respectively. The results of the calculated annual effective doses for different age groups due to ingestion and the health implication with respect to the hazard limit set by the International Commission on Radiological Protection (ICRP) were considered.