Annual Effective Dose and Lifetime Cancer Risks Due to Natural Radioactivity in Hand –Dug Well Water of Tai Rivers State, Nigeria

The presence of radionuclide in water poses a number of health hazards, especially when the radionuclide is deposited in the human body through drinking water. The aim of this study was to evaluate natural radioactivity and its associated health risk in hand dug well water of Tai Local Government Area of Rivers State, Nigeria by means of gamma spectroscopy techniques and radiation models. The well water was collected from five selected coastal communities of Tai and chemically treated by adding nitric acid and then pre-concentrated further by evaporating to certain levels and kept in marineli beaker properly sealed for 28 days, after which was counted with NaI(Ti) detector. The mean values of specific activity concentration of 40K, 226Ra and 228Ra(232Th) were 25.90, 19.21 and 18.50 Bql-1 respectively. The annual effective doses for different age categories were estimated taking into consideration the ingested dose conversion factors as well as their yearly average water consumption. The average annual effective dose estimated for infants, children, teenagers and adult population were 0.115, 0.027, 0.071 and 0.013 Svy-1 respectively. The annual effective dose due to ingestion of the sampled water were above the recommended values by WHO, IAEA and UNSCEAR for the age brackets. The paper presents the overview of the techniques used and the summary of the findings. The result of this study gives the radiological baseline data for effective monitoring of the study area.