Browsing by Author "Kibe, Horace Eyinda"

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    A Comparative Study of Natural Radioactivity and Associated Radiological Hazards of Imported Sanitary Ware Products Sold in Kenya
    (IRESPUB Journal of Natural & Applied Sciences, 2024-08-25) Natang’ah, Edwin Chemos; Waswa, Michael Nakitare; Khakina, Peter Nyongesa; Kibe, Horace Eyinda
    Natural radioisotopes are present in all ceramic products used in building construction at varying rates. The primary source of outdoor radiation that residents of homes or workplaces are exposed to is these radioisotopes. Determining the radiation levels of ceramic items used in buildings is crucial. In this investigation, Thallium doped sodium iodide detector NaI(Ti) was used to measure the natural radioactivity levels (226Ra, 232Th, and 40K) in twelve ceramic sanitary ware products manufactured in India, China and Uganda imported and used in Kenya. For the studied samples, the average activity concentrations of 226Ra, 232Th, and 40K radionuclides were 19.5±0.99Bq/kg, 89.75±4.49Bq/kg and 405.75±20.29Bq/kg for 226Ra, 232Th and 40K respectively. With the exception of the average 232Th concentration of studied samples, these results are lower than the global average values (50, 50, and 500 Bq/kg).Values for radium equivalent activity (Raeq), gamma index (Iγ), external hazard index (Hex), internal hazard index (HIn), absorbed dose rate (ADR), annual effective dose (AED), and excess lifetime cancer risk (ELCR) were also computed in order to assess the radiological risks resulting from naturally occurring radionuclides of the ceramic sanitary ware samples under examination. The mean of the radioactive hazard parameters (Raeq, Iγ, Hex, HIn ,D, and AEDE,) computed for every sample of ceramic sanitary equipment was discovered to be below the upper bounds suggested by global organization safe for ELCR which registered slightly higher values.
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    Environmental Radiation Exposure and Lifetime Cancer Risk at Lumoru Dumpsite, Western Kenya
    (Open Access Library Journal, 2025-11-18) Wanjala, Bilha; Nyukuri, Robert Wanjala; Kibe, Horace Eyinda; Makokha, John Wanjala
    This study quantified the activity concentrations of natural radionuclides 238U, 232Th, and 40K in soils from the Lumoru Dumpsite, Bungoma County, Kenya, using a NaI (Tl) gamma spectrometer. The mean concentrations were 7 ± 0.4 Bq/kg for 238U, 57 ± 2.0 Bq/kg for 232Th, and 25 ± 1.3 Bq/kg for 40K. From these values, the absorbed dose rate was estimated at 39 ± 3.4 nGy/h, the outdoor annual effective dose equivalent at 0.09 ± 0.01 mSv/y, and the radium equivalent activity at 91 ± 3.4 Bq/kg. The hazard indices (Hex = 0.25 ± 0.01; Hin = 0.28 ± 0.01) were all within international safety limits, while the mean excess lifetime cancer risk was 0.30 ± 0.03 × 10−3. Compared with similar dumpsites in Kenya and across Africa, Lumoru exhibited lower activity concentrations and radiological risks than Machinjoni, Nigerian, and Ukrainian landfills, though its risks remain comparable to food-chain pathways in Bungoma. These findings establish Lumoru as a moderately impacted site and provide a critical baseline for monitoring cumulative exposures from environmental and household sources in Western Kenya.