| dc.description.abstract | Both immediate and long-term health problems can result from exposure to high and moderate intensity radiation. This study looked into the amounts of naturally occurring radioisotopes that produce gamma rays in soil samples that were taken from several sites in Embu County's Mbeere North area. Although the native society in central-eastern Kenya relies heavily on this region for construction bricks, the radiation safety of this raw material has not yet been evaluated. Furthermore, there has been a significant increase in cancer incidence in Embu County and the surrounding areas, albeit the exact cause remains unknown. Fifty soil samples weighing roughly 1000 g each were collected at a deepness of roughly 10 cm from various positions in the Mbeere North region. From each location, three samples weighing around 350 g were collected from a 1 m by 1 m area, which were then combined to create a single representative sample. The inter-sampling distance varied between sites but was kept within 4 to 5 km. Special attention was given to areas involved in brick making. In cases where brick-making sites were distant, samples were collected from areas with other anthropogenic activities, such as quarrying, sand harvesting, and farming of crops like Catha edulis (khat), cowpeas, sunflowers, and green grams. Each sampling site's coordinates were recorded using global positioning system (GPS) technology. Using a sodium iodide activated with thallium (NaI(Tl)) gamma-ray spectrometer, the radioactive decomposing rates of 232Th, 238U, and 40K in the soil samples were determined. 232Th, 238U, and 40K were pinpointed to have mean activity absorptions of 149.74±2.82 Bqkg⁻¹, 88.34±2.39 Bqkg⁻¹, and 490.35±35.24 Bqkg⁻¹, respectively. These concentrations were higher than the global median of 45, 33, and 420 Bqkg⁻¹ for these radionuclides. It was discovered that these radionuclides had an uneven spatial distribution throughout the area.157.93±4.40 nGyh⁻¹, 0.58±0.02 mSvy⁻¹, and 0.39±0.01 mSvy⁻¹ were the mean absorbed dosage, and innermost and outmost yearly effective dose rates, following that order. The absorbed dosages in around 0.96 of the cases were greater than the 57 nGyh⁻¹ global mean. Despite this, all values were beneath the 1500 nGyh⁻¹ suggested safe end. Effective dose rates indoors were below the permissible level of 1 mSvy⁻¹ in about 0.94 of the samples, and all outdoor yearly effective dose rates were unbefitting this limit as well. Internal hazard indicator, exterior risk index, and radium equivalent had mean values of 1.14±0.03, 0.92±0.02, and 340.70±9.20 Bqkg⁻¹, singly. The mean internal hazard indicator was the sole radiation safety needle that was marginally above the safe gauge. Therefore, it is deemed safe to utilize the soils from Embu County's Mbeere North region for brick-molding and fabrication. | en_US |
