Radiological and Chemical Risk Assessment of Uranium in Underground Water around Mining Site, Saki, Nigeria

Uranium is present in most underground water sources and it properties as a heavy metal and radioactive elements can determine the safety of such water when consumed. Consumption of elevated uranium as a heavy metal and a radioactive element in drinking water can lead to non-cancer. The activity concentrations of Uranium in 20 well and 20 borehole water in Saki around mining site were measured using Sodium Iodide detector. The results obtained were used to calculate chemical and radiological risk over lifetime consumption by the population in the area. The mass concentration values in the borehole water samples ranged from 139.84 to 378.40 Bql-1 and that of well water samples ranged from 233.73 to 367.12 Bql-1. Both the mass concentration values of borehole water and well water samples exceeded the recommended safe limit of uranium in drinking water of agencies like WHO and USEPA. This shows a chemical risk associated to the consumption of the water samples. The excess cancer mortality risk of the samples investigated ranged from 2.02x10-4to 5.41 x10-4 for the borehole and 3. x10-4to 5.32 x 10-4 the well water while the excess cancer morbidity risk of uranium in the samples are 3.06 x 10-4 to 8.30 x 10-4 and 5.13 x10-4 to 8.15 x10-4 for borehole and well water respectively. Both its excess mortality and morbidity risk fell below the permissible value of 10-3. Therefore the water samples are radiologically safe for drinking and pose no radiological hazard to the consumers.