Assessment of Natural Radionuclides and Their Associated Radiogenic Heat Production in Soils of Ahero Fields, Kisumu County, Kenya

Michael Nakitare Waswa* & Kere Mukanda Wanyama

Department of Science, Technology and Engineering, Kibabii University, Kenya

Abstract

The activity concentrations of the three radionuclides: 238U, 232Th and 40K in the soils of Ahero fields were determined using NaI(Ti) detector employing the gamma ray spectroscopy technique at Kenyatta University physics laboratory. The activity concentrations were then converted into radioelement concentrations in ppm (238U and 232Th) and % (40K) that were used in obtaining Radiogenic Heat Production (RHP).The average activity concentrations for the various fields were: for field 1: 32.63 ± 1.63 Bq/kg for 238U, 104.69 ± 5.20 Bq/kg for 232Th and 75.00 ± 3.2 6 Bq/kg for 40K. The average activity concentrations of 238U and 40K for fields 2, 3 and 4 were within the world average values except for 232Th that was 68.03 ± 3.40 Bq/kg, 91.73 ± 4.58 Bq/kg and 121.11 ± 6.05 Bq/kg for fields 2, 3 and 4 respectively that were above the world average of 45 Bq/kg. The RHP values ranged from a minimum of 2.4 µW/m3 to a maximum of 9.0 µW/m3 with an average of 4.8 µW/m3. The findings on natural radioactivity will inform the various stake holders on setting up of standards and guidelines to safeguard the general public against exposure to high background radiation. The data on RHP will form a baseline information for other studies in other areas and hence may prompt a possible exploitation of geothermal energy. 

Keywords

Radiogenic heat production; natural radioactivity

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