Abstract

---

The studies investigate the physicochemical properties and concentration of radioactive elements present in the geophagious ‘Nzu clay’ samples obtained from Azonogogo, Delta State and Uzella River, Owan West LGA, Edo State. The mineral composition of the clay samples were investigated using XRD while the radioactive elements were determined by using Hiper Pure Gammanium detector with Resolution (FWHM): 2.3 Kev, 60Co at 1.33Mev. The result of the physicochemical properties shows that water absorption and swelling power of processed/finished ‘Nzu clay’ obtained from Uzella River have the highest values of 2.230±0.000 and 2.070±0.000 respectively. The pH of the raw and processed/finished ‘Nzu clay’ is 5.150±0.494 and 4.500±0.141 respectively, showing increased acidity in the clay. The levels of radioactive elements in ‘Nzu Clay’ indicated that the average specific activities of 40K, 238U and 232Th ranged from 54.45±32.45 to 127.60±14.7, 21.35±6.28 to 38.75±4.67 and 26.83±13.94 to 44.51±1.16 respectively. The mean absorbed dose rate and annual Gonadal Equivalent Dose (AGED) of the ‘Nzu Clay’ was calculated to be 48.86 nGy/h and 207.1Sv/y, respectively. The XRD analysis reveals that the ‘Nzu clay’ is dominantly composed of the mineral Kaolinite and Quartz. The presence of these radioactive elements, though not beyond the permissible limits put the habitual consumer at health risk on the long run.

Keywords: Geophagious, radioactive, absorbed dose, Hiper Pure Gammanium detector, habitual consumer