Abstract
The risk of natural terrestrial radioactivity on human health is often underestimated, and environmental safety awareness is necessary. Hence, this study aims to assess natural sources of gamma radiation emitter in coastal urban-environment using the radiometric technique. The dosage of gamma radiation from a parent radionuclide such as Uranium-238 (238U), Thorium-232 (232Th) and Potassium-40 (40K) and were measured using portable gamma spectroscopy. The result showed that the measured value of 238U activity was between 10.81 pm 0.69 and 46.31 pm 1.43 Bqkg−1. The mean value was estimated to be 35.44 pm 0.97 Bqkg−1 which is slightly higher than the world average. Meanwhile, 232Th activity ranges from 28.42 pm 1.12 to 69.43 pm 1.76 Bqkg−1 with the calculated mean value of 92.57 pm 1.17 Bqkg−1 while 40K activity ranged between 31.30 ± 1.32 and 328.65 ± 2.32 Bqkg−1 with the estimated mean 137.59 pm 2.42 Bqkg−1. Radiological parameters such as radium equivalent (Req), internal hazard (Hint) and external hazard (Hext) assessment were in the range of 66.00 Bqkg−1 to 141.76 Bqkg−1, 0.232 to 0.452 and 0.178 to 0.383, respectively. The measured values of gamma dose-rates ranged between 54.283 ± 0.78 and 117.531 ± 1.14 nGyh−1 with the calculated mean value of 84.770 ± 0.97 nGyh−1.
Highlights
The risk of natural terrestrial radioactivity on human health is often underestimated, and environmental safety awareness is necessary
The measured radionuclides and the distribution patterns for Uranium-238 (238U), Thorium-232 (232Th), and Potassium-40 (40K) from 120 sampling points in the study area are shown in Table 1, Figs. 3, 4, and 5, respectively
It was observed that the highest value of 46.31 ± 1.43 Bqkg−1 of Uranium-238 measured was noted at measuring location 71, while the lowest value of 10.81 ± 0.69 Bqkg−1 was reported at measuring area 31
Summary
The risk of natural terrestrial radioactivity on human health is often underestimated, and environmental safety awareness is necessary. Gamma-emission, which originates from natural sources, is a result of primordial radionuclides, which are mainly Thorium-232 (232Th) and Uranium-238 (238U) series and their bye-decay products, and likewise, Potassium-40 (40K), which occurs as a trace-element in the earth’s subsurface. These occurring natural radionuclides are dependent on the local geology of each area in the world[4]. The radionuclides that can be found in the environment are more than sixty (60) These are grouped into three (3) categories, namely cosmogenic (which occurs as a result of the interaction of rays from cosmic bodies), anthropogenic activities (occur through human technological development), and primordial (which exist before the creation of earth). Besides the radiation effect that emanates from the soils due to population exposure that uses grounds as a building material, the human body can be affected by taking food consisting of radionuclide as a contaminant through the food chain from deep soil layers[10,11,12,13,14,15,16,17,18,19,20]
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