Radiometric Assessment of Natural Radioactivity Levels around Mrima Hill, Kenya
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Date
2011-03-10
Authors
Kebwaro, J. M.
Rathore, I. V.
Hashim, N. O.
Mustapha, A. O.
Journal Title
Journal ISSN
Volume Title
Publisher
International Journal of the Physical Sciences
Abstract
Mrima Hill, located in the South coast of Kenya is known for high natural background radiation, due to
the presence of radiogenic heavy minerals such as monazites and carbonatites. The activity
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concentration of U, Th and K in soil samples from the hill have been determined by gamma ray
spectrometry using NaI(Tl) detector and decomposition of measured gamma-spectra. As a measure of
radiation hazard to the public, gamma radiation dose rates were also estimated. The average activity
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concentrations of U, Th and K were 207.0±11.3, 500.7±20.0 and 805.4±20.0 Bqkg, respectively.
The mean absorbed dose rate in air is 440.7±16.8 nGyh-1 while the estimated annual average effective
dose rate is 1.11±0.01 mSvy-1. The absorbed dose rate due to gamma radiation from naturally occurring
radioactive materials is above the global average value of 60 nGyh-1 (UNSCEAR, 2000).
Description
DOI: 10.5897/IJPS11.052
Keywords
High natural background radiation, gamma ray spectrometry, NaI(Tl) detector, Mrima Hill
Citation
International Journal of the Physical Sciences Vol. 6(13), pp.3105-3110, 4 July, 2011