Browsing by Author "Mukanda, Kere Wanyama"

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Assessment of Natural Radionuclides in the Top Soil Sample of Ahero Fields, Kenya
(International Journal of Modern Developments in Engineering and Science, 2023-05-22) Mukanda, Kere Wanyama; Waswa, Michael Nakitare; Ouma, Linda Immaculate
A total of 17 soil samples of Ahero fields were collected at a depth of 15 – 20 cm; five samples each of mass 170g were collected from field 1, 2, 3 and two samples from field 4. The field 1 was where rice seedlings were already transplanted, field 2 was one in which transplanting was being done, field 3 was one in which rice had been harvested and the field had just been ploughed while field 4 was a field in which farming had not been done for two years. The activity concentrations were measured, identified and detected using NaI(Ti) detector that were used in calculation of Radium Equivalent, External Hazard Indices and Internal Hazard Indices. The average radium equivalent were 185.82 ± 7.04 Bq/kg, 119.19 ± 5.95 Bq/kg, 168.78 ± 8.44 Bq/kg and 208.81 ± 10.44 Bq/kg for fields 1, 2, 3 and 4 respectively. The average internal hazard index was 0.50 ± 0.02 mSv/y, 0.32± 0.01 mSv/y, 0.45 ± 0.03 mSv/y and 0.57± 0.03 mSv/y for fields 1, 2, 3 and 4 respectively. On the other hand, the average external hazard indices for the fields were 0.59 ± 0.02 mSv/y, 0.37± 0.01 mSv/y, 0.54± 0.02 mSv/y and 0.65± 0.03 mSv/y for fields 1, 2, 3 and 4 respectively. Generally, the results from the study indicate that the radiological health risk associated with the top soils of the studyarea is insignificant.
Radiological Risk Assessment of 238u, 232th And 40k in the Top Soils of Ahero Paddy Fields of Kisumu County, Kenya
(Journal of Engineering and Technology for Industrial Applications, 2022-08-22) Mukanda, Kere Wanyama; Waswa, Michael Nakitare; Ouma, Linda Immaculate
A radiological risk assessment of 238U, 232Th and 40K in the top soils of Ahero paddy fields of Kisumu County has been measured using NaI(TI) gamma ray spectroscopy. A total of 17 samples were collected at a depth of 15 - 20 cm and measured for activity concentrations of three radionuclides which were used to calculate the absorbed dose rates and Annual effective dose rates of the samples. Samples were collected from fields at various stages of farming process i.e., four (4) weeks after transplanting (field 1), during transplanting (field 2), after harvesting and land ploughed (field 3) and a control field (field 4) where rice farming had not been done for 2 years. The average activity concentrations for the three radionuclides for field 1 were 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 the radionuclides from field 2 were 16.97 ± 0.84 Bq/kg, 68.03 ± 3.40 Bq/kg and 70.31 ± 3.51 Bq/kg for 238U, 232Th and 40K respectively. The average activity concentrations of the radionuclides from field 3 (post harvesting) were 28.92 ± 1.44 Bq/kg, 91.73 ± 4.58 Bq/kg and 122.60 ± 6.13 Bq/kg for 238U, 232Th and 40K respectively. The average activity concentrations of the radionuclides were 29.74 ± 1.48 Bq/kg, 121.11 ± 6.05 Bq/kg and 87.51 ± 4.37 Bq/kg for 238U, 232Th and 40K respectively. The average Absorbed Dose Rates were 81.50 ± 4.07 nGy/h for field 1, 52.59 ± 2.62 nGy/h for field 2; 74.68 ± 3.73 nGy/h for field 3 and 91.79 ± 4.59 nGy/h for field 4. The values were below the permissible limit of 1500 nGy/h, thus the radiological risk associated with the top soils of the Ahero Paddy fields of Kisumu County, Kenya is insignificant.