Investigation of the state of radioactive equilibrium of uranium in rock samples from some areas of Cross River State, S.E. Nigeria

Abstract

A comparison of the «chemical» uranium concentrations in rock samples from Cross River State, Nigeria, measured using instrumental neutron activation analysis, have been compared with the γ-ray activities of the radium and uranium groups for the same samples. The comparisons show a linear correlation between the uranium concentrations and the 234 Th (uranium group) counts. No such correlation occurs between the uranium concentration and the 226 Ra (radium group) counts. In other words, γ-ray equivalent uranium concentrations (eU) derived from the activities of two daughters in the uranium and radium groups of the uranium series are different, implying disequilibrium in the uranium series. Further analyses reveal that the ores are richer in radium; perhaps due to leaching of the uranium by surface and underground water in the area