Determination of radioactivity levels of soil samples and the excess of lifetime cancer risk in Rize province, Turkey

Abstract

Human beings are exposed to background radiation that stems both from natural and manmade sources. Natural background radiation, which is equivalent to 2.4 mSv per person, makes up approximately 80% of the total radiation dose a person is exposed in a year (1). Soil radionuclide activity concentration is one of the main determinants of the natural background radiation. Volcanic geographic structures as well as rocks that are rich in phosphate, granite and salt contain natural radionuclides like 238 U, 232 Th and 40 K. When rocks are disintegrated through natural processes, radionuclides are carried to the soil by rain and .lows (2). The natural radioactivity in soil comes from 226 Ra, 232 Th and from natural 40 K. Some other terrestrial radionuclides, including those of the 235 U series, 87 Rb, 138 La, 147 Sm and 176 Lu exist in nature but at such low levels that their contributions to the dose in the humans are small. Arti.icial radionuclides can also be present such as 137 Cs, resulting from fallout from weapons testing. 137 Cs is a .ission product which is formed through nuclear tests and accidents. The deposition of 137 Cs in soil is important since its half-life is 30.2 years and it has a gamma emission of 661 keV (3). The radiological

Radionuclides proportion and radiological risk assessment of soil samples collected in Covenant University, Ota, Ogun State Nigeria

“…In addition, the average activity concentrations for 238 U and 232 Th in the present study, were found to be higher than the world recommended standard of 35 and 30 Bq/kg, while it is lower in 40 K than the world standard of 400 Bq/kg as reported by UNSCEAR [ 19 ]. The result of the activity concentrations of 238 U and 232 Th in the present study are higher than the result obtained in Dizman et al [ 3 ] and Usikalu et al (2017), while the activity level of 40 K, in the current research, is far lower than the result of the previous study. Furthermore, the activity concentration of 238U in Amanjeet et al [ 27 ] corresponds with the activity levels of 238 U in the present study while the concentration levels of 232 Th and 40 K in the previous study were far higher than the present study.…”

“…Natural radionuclides spread widely in soils, sediments and rocks. Natural background radiation is determined by the activity of the radionuclide content in soil [ 2 , 3 ]. Although, geologic features as well as the activities of man can trigger the level of radioactivity in soil [ 4 , 5 ].…”

“…In order to avoid these kinds of disease, it is essential to assess the natural environmental radioactivity and its associated gamma radiation so as to ascertain the safety of the residents of the geographical location. Dizman et al [ 3 ] established the possibility of the annual effective gamma doses and life time cancer risks being higher than the world’s recommended average, while investigating the background radiation level in soil in order to estimate the associated health risks. Korkmaz et al [ 7 ] observed that adequate information on the distribution of radionuclide in the environment is very expedient for radiation measurement and protection [ 9 , 10 ].…”

Gamma Background Radiations and Measurements with Applications

“…Yearly viable gamma dosages and the presence dangers of disease were higher than the world's normal. Besides contrast with the World's normal, the existence time danger of malignancy is multiplied for a large portion of the territories [48].…”

Determination of the Radiation Hazard Indices and Excess Lifetime Cancer Risk in Iraqi Bentonite

“…The total air absorbed dose rate results from the mean activity concentration of 238 U, 232 Th and 40 K has been calculated using the following expression utilizing the factors , and for 238 U, 232 Th and 40 K respectively [12,13], Also, the annual effective dose has been measured using outdoor occupancy factor (OF), where it is 20% of 8760 hours per year or 0.2 of 8760, and the conversion coefficient from absorbed dose in air to an effective dose of 0.7 [12,8]. The annual effective dose was estimated using the following expression [8,14] 5Another essential criterion used to evaluate the level of gamma radiation is defined by the external hazard index (H ex ), which defined as follows [15,16,17] The measured values of activity concentrations can be used to extend the evaluations, and estimate the excess lifetime cancer risk (ELCR), to predict the risk that human being might infect cancer due to exposing to cancer-causing materials for extended long time [14,18,19]. The total ELCR was calculated using the estimated annual effective dose, and given by [20],…”