MEASUREMENT OF ~(238)U, ~(232)Th AND ~(40)K IN BOREHOLES AT GOSA AND LUGBE, ABUJA, NORTH CENTRAL NIGERIA

摘要

The purpose of this project is to evaluate the suitability of different sites as locations for obtaining underground water for consumption. The analysis of ~(238)U, ~(232)Th and ~(40)K from rock samples from each layer of borehole at a depth of ～50 m at Site A borehole, S3L1-S3L6 in Gosa and 40 m at Site B borehole, S4L1-S4LS in Lugbe, Abuja, north central Nigeria is presented. The gamma-ray spectrometry was carried out using a high-purity germanium detector coupled to a computer-based high-resolution multichannel analyzer. The activity concentrations at Site A borehole for ~(238)U have a mean value of 26 ± 3, ranging from 23 ± 2 to 30 ± 3 Bq kg~(-1), ~(232)Th a mean value of 63 ± 5, ranging from 48 ± 4 to 76 ± 6 Bq kg~(-1) and ~(40)K a mean value of 573 ± 72, ranging from 437 ± 56 to 821 ± 60 Bq kg~(-1). The activity concentrations at Site B borehole for ~(238)U have a mean value of 20 ± 2, ranging from 16 ± 2 to 23 ± 2 Bq kg~(-1), ~(232)Th a mean value of 46 ± 4, ranging from 43 ± 4 to 49 ± 4 Bq kg~(-1), ~(40)K a mean value of 915 ±116 and ranging from 817 ±103 Bq kg~(-1) to 1011 ±128 Bq kg~(-1). It is noted that the higher activity concentrations of ~(232)Th and ~(238)U are found in Site A at Gosa. Site B has lower radioactivity, and it is recommended that both sites are suitable for underground water consumption.