Evaluation of specific natural radioactivity in drinking well, tap and river waters in OML30 oil and gas field of Delta State, South-South Nigeria

The oil and gas rich Niger Delta region of Nigeria is characterised by environmental degradation leading to regional climate change chief of them is water pollution from oil and gas activities. This paper present the natural occurring radionuclides (226Ra, 232Th and 40k) carried out in three source of water supply (well ,tap and river water) collected from OML30 oil and gas field block, onshore of Niger Delta, using gamma spectroscopy operated on a Canberra 3'' x 3'' NaI(TI) detector. Thirty water samples, ten each from the three source of water supply were collected within the oil field and host communities and three samples from a control site. They obtained natural activity concentration of 226Ra, 232Th and 40k is 7.2±0.8, 5.5±0.5 and 31.9±2.2 Bq/l respectively for well water, 5.5±0.7, 5.2±0.5 and 29.0±2.8 Bq/l respectively for tap water, while it is 15.4±1.4, 10.4±0.9 and 41.8±2.8 Bq/l respectively for river water. This value obtained is those of the control site values, world average values and most reported concentration around the world. But the hazard indices (Raeq, Hex, Hin) examined and the committed effective dose estimated are within their permissible limits.