Radioactivity level of dug well water across selected cities in two states of Nigeria. Issue 4 (2nd October 2017)

• Record Type: Journal Article
• Authors: Ayodele, A. E.; Arogunjo, A. M.; Ajisafe, J. I.; Arije, O. T.
• Is Part Of: Environmental forensics. Volume 18:Issue 4(2017)
• Page Start: 331
• Page End: 338
• Publication Date: 2017-10-02
• Subjects: Dug well -- HPGe -- annual effective dose -- committed effective dose; Environmental forensics -- Periodicals; Pollution -- Measurement -- Periodicals; Environmental law -- Periodicals; Enquêtes environnementales -- Périodiques; 363.25945
• DOI: 10.1080/15275922.2017.1368041
• Languages: English
• ISSNs: 1527-5922

Abstract

ABSTRACT: Over the years, municipal water supplies have been found to contain radionuclides, but data regarding the level and the associated radiological implications in many environmental samples are still sparse in towns and cities of developing nations around the world. Hence, the activity concentrations of radionuclides present in 16 dug well water samples taken from selected cities across Ondo and Ekiti states, Nigeria, have been determined using an n-type coaxial HPGe gamma-ray detector with ORTEC Multichannel Analyzer (MCA). The activity concentration of gamma emitter radionuclides in the well water ranged from 1.59 ± 0.44 to 3.75 ± 0.67Bq/L for 232 Th, 6.43 ± 1.33 to 12.59 ± 1.50Bq/L for 226 Ra, and 35.81 ± 2.78 to 70.38 ± 3.46Bq/L for 40 K in Ondo state, and 0.45 ± 0.24 to 33.15 ± 5.99Bq/L for 232 Th, 2.08 ± 0.53 to 78.36 ± 14.17Bq/L for 226 Ra, and 34.47 ± 2.88 to 556.90 ± 30.73Bq/L for 40 K in Ekiti state. Total annual effective dose equivalents resulting from exposure to these radionuclides from the untreated dug wells were estimated using the measured activity concentration and the dose conversion factor for three different age groups. The mean total annual effective dose equivalents for each of the age groups (0–1 y, 7–12 y, > 17 y) resulting from the radionuclides in the well water samples of both Ondo and Ekiti States were (11.49 ± 1.92, 3.02 ± 0.48, 2.52 ± 0.41) mSv/y and (26.52 ± 5.33, 6.63 ± 1.32, 5.77 ± 0.76) mSv/y respectively. This is above the International Centre for Radiation Protection (ICRP)-and WHO-recommended limits of 1 mSv/y and 0.1 mSv/y respectively. Hence, the dug wells across the studied area are recommended for conventional water treatment to remove radionuclides. The estimated values of total annual effective dose equivalent and committed effective dose were presented for three different age groups (i.e., 0–1 y, 7–12 y, > 17 y) and > 17 y respectively.