Investigation of Gamma-Emitting Natural Radioactive Contents in Three Types of Vernonia Consumed in Cameroon

Abstract

The specific activity concentration and the derived Annual Effective Dose(AED) in three types of vernonia cultivated and consumed within and outside Cameroon were measured by means of a well-calibrated high-purity germanium detector. Vernonia samples were collected directly from the production farms, oven-dried to a constant mass, crushed, sieved and sealed for at least a month before analysis. The specific activity of <sup>238</sup>U in the three types of vernonia ranged from 20 - 50 Bq kg<sup>-1</sup> with an average of 42 ± 15 Bq kg<sup>-1</sup>, <sup>232</sup>Th from 9 - 22 Bq kg<sup>-1</sup> with an average of 17 ± 7 Bq kg<sup>-1</sup> while <sup>40</sup>K ranged from 115 - 460 Bq kg<sup>-1</sup> with an average of 302 ± 36 Bq kg<sup>-1</sup>. The average AED for <sup>40</sup>K, <sup>238</sup>U and <sup>232</sup>Th were 0.15, 0.92 and 0.92μSv y<sup>-1</sup> respectively. <sup>238</sup>U and <sup>232</sup>Th show the same trends both for the regional distribution of the radioactivity content and the AED. The discrepancies in our data can be attributed to many factors such as geological formation, foliar deposition, type and age of the plant, etc. Although the results obtained represent only some fractions of the standard limit, but they are within some range obtained in other countries

Assessment of Radioactivity Levels and Transfer Factor of Natural Radionuclides Around Iron and Steel Smelting Company Located in Fashina Village, Ile-Ife, Osun State, Nigeria

“…However, 40K is an essential biological element and its concentration in human tissue is under close metabolic (homeostatic) control (UNSCEAR, 1982). Variation of 40K concentration in dietary composition do not influence significantly the radiation dose received (Makon et al, 2011). The result of this study is in comparison with the values recorded for activity concentration of radionuclides in vegetables, grains and tubers collected in oil and gas areas in the Niger Delta region in Nigeria as reported by Avwiri et al, (2013) and Tchokossa et al, (2013).…”

Assessment of Radioactivity Contents and Associated Risks in Some Soil Used for Agriculture and Building Materials in Cameroon

“…Here in Nigeria, Tchokossa and his co-workers reported the results of many investigations on the distribution of radioactivity content in various environmental matrices [12][13][14][15][16][17][18][19], while in Cameroon, Makon et al carried out similar research in some edible vegetable cultivated and consumed worldwide [20]. Cameroon is located at the center of both operational and non-operational nuclear reactors and industries (Figure 1), and to the best of my knowledge, there is no published or on-going works on the survey of Cameroonian's soil.…”

“…At each location, well described elsewhere [20], the samples were collected at the depth between 0 -30 cm, at the four corners and the center of a square frame of 1 m size and later composed to make a single sample. Samples were collected in their natural form, dried at room temperature to a constant weight, grounded and sieved to a 2 mm size.…”

Background Radiation from 238U, 232Th, and 40K in Bells Area and Canaan City, Ota, Nigeria

“…Its concentration in human body is under close metabolic (homeostatic) control [29]. Hence, its concentration variation in dietary composition does not influence significantly the radiation dose received in human body [4], [30].…”