Title: Assessment of γ-radiation levels and associated dose rates from surface soils in the eastern part of Botswana

Authors: Alfred Sello Likuku; Naregundi Karunakara; Gothatamang Patrick Nthoiwa

Addresses: Department of Basic Sciences, Botswana College of Agriculture, Private Bag 0027, Gaborone, Botswana ' University Science Instrumentation Centre, Mangalore University, Mangalagangotri 574199, Mangalore, Karnataka, India ' Department of Basic Sciences, Botswana College of Agriculture, Private Bag 0027, Gaborone, Botswana

Abstract: This paper reports the γ-radiation levels of the naturally occurring ⁴⁰K, ²¹⁰Pb, ²³²Th and ²²⁶Ra and the anthropogenic ¹³⁷Cs in the eastern part of Botswana so as to assess their possible dose impact to the members of the public in the area. The radium equivalent activity was (175±24) Bq/kg, and thus below the allowed maximum value of 370 Bq/kg. The total absorbed rate ranged from 24.12 nGy/h to 215.44 nGy/h with the mean of (81.36±10.58) nGy/h. The outdoor annual effective dose ranged from 0.030 mSv/y to 0.264 mSv/y with an average value of (0.10±0.01) mSv/y. The obtained values are comparable with world-wide averages. Results from this study can be used to serve as baseline data for the study area, which can also be used as reference information to assess any changes in radioactivity background possibly due to the artificial influences.

Keywords: radionuclides; activity concentrations; radium equivalent activity index; gamma radiation; absorbed dose rate; outdoor effective dose rate; radiation levels; surface soils; Botswana; background radioactivity.

DOI: 10.1504/IJLR.2014.068259

International Journal of Low Radiation, 2014 Vol.9 No.5/6, pp.344 - 354

Received: 28 Dec 2013
Accepted: 22 Aug 2014
Published online: 27 Mar 2015 *

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