Measurement Of Natural Radioactivity Level And Radilogical Hazards In Sample Of Bale Zone Oromia Ethiopia Using Gamma Spectrometry

In this study, our objective was to measure the level of activity concentration andrnradiological hazards of soil samples from agricultural and virgin lands of Bale zone,rnOromia, Ethiopia. The activity concentrations of naturally occurring radionuclidesrn238U, 232Th, and 40K were calculated total for of twelve(12) which is six(6) fromrnagricultural and the other six(6) from virgin soil samples randomly collected fromrnfour kebele's of Bale zone southeastern part of Ethiopia by mixing equal masses ofrnsoil from three di_erent depths starting from 0 to 10cm,then 0 to 20cm, and 0 torn30cm. Gamma-ray spectrometer was applied using high-purity germanium (HPGe)rngamma-ray detector and a PC-based MCA that uses Genie 2000 Spectroscopy Software.rnAdditionally, in our some soil samples of two sites there is an arti_cial radionuclidernof 137Cs that fallout from any nuclear accidents can be seen when thernsamples analyzed by Gamma-ray spectrometry using high-purity germanium. Thernmean value of radioactivity concentrations of 238U , 232Th, and 40K were found to bern21:74_0:569 with ranged from 6:565_0:206 to 41:15_0:748, 71:72_1:95 with rangedrnfrom 26:2_0:77 to 122_2:57 and 1111:5_3:39 Bq kgÀ€€1 with ranged from 555_8:94rnto 2180 _ 3:21 Bq kgð€€€1 , respectively, in agricultural soils and 18:89 _ 0:667 withrnranged from 7:54_0:378 to 30:25_1:340, 69:93_2:38 with ranged from 36:2_0:96rnto 121:0_2:55, and 642:83_4:39 Bq kgð€€€1 with ranged from 413_7:01 to 808_1:21rnBq kgð€€€1 , respectively, in virgin soils. The radioactivity concentrations in agriculturalrnsoils are higher than those in virgin soils as of phosphate fertilizers added tornagricultural land soils. Out of twelve samples the activity concentrations of the artirn_cial radionuclide 137Cs was measured by HPGe only in six samples. The meanrnvalue was 1:542 _ 0:635 Bq kgð€€€1 with ranged of 0:451 _ 0:507 to 2:19 _ 0:151 Bqrnkgð€€€1. The minimum activity concentration value of 137Cs was obtained for a soilrnsample collected from virgin land, similarly the maximum value was measured in arnsoil sample collected from virgin land site, which is no health e_ects on the peoplernliving around the sites where soil samples were collected.rnThe Gamma-ray radiation of radiological hazards caused by speci_c radionuclidesrnof 238U, 232Th, and 40K was evaluated using di_erent hazard indices. Thernmean values of radium equivalent activity (Raeq), absorbed dose rates (DR), annualrne_ective dose(ADR), external hazard index(Hex), and internal hazard index(Hin)rnare 209:88 _ 3:617 Bqkgð€€€1 which ranged from 93:45 _ 2:110 to 296:46 _ 4:543 Bqrnkgð€€€1, 101:76 _ 1:873 nGy hð€€€1 which ranged from 45:85 _ 1:001 to 138:73 _ 1:988rniiirnnGy hð€€€1, 0:12 _ 0:002 mSvyð€€€1 with ranged from 0:06 _ 0:001 to 0:17 _ 0:002mSvrnyð€€€1, 0.57, ranged from 0.25 to 0.80, and 0.625, ranged from 0.29 to 0.91, respectively,rnwere found in agricultural soils and 168:40_4:402 Bqkgð€€€1 with ranged fromrn98:92 _ 2:283 to 256:05 _ 4:147 Bqkgð€€€1, 79:28 _ 1:954 nGy hð€€€1 with ranged fromrn46:87 _ 1:058 to 119:01 _ 1:815 nGy hð€€€1, 0:098 _ 0:002 mSv yð€€€1 with ranged fromrn0:06 _ 0:001 to 0:15 _ 0:002 mSv yð€€€1, 0.46 with ranged from 0.27 to 0.69, and 0.51rnwith ranged from 0.31 to 0.75, respectively, were found in virgin soils samples. Further,rnthe annual dose rate was calculated only for outdoor. In a comparison of thernworld wide average value calculated by UNSCEAR and ICRP with our results meanrnvalue for absorbed dose rates (DR),and annual e_ective dose(ADR) were out of thernrecommended mean values of 59nGy/h and 0.07mSv/y by these institutions. But,rnothers like radium equivalent activity (Raeq), external hazard index(Hex), and internalrnhazard index(Hin) mean values were within the recommended value. Finally,rnin all radiological hazard indices when we compare two sites( agricultural and virginrnlands), the mean values of agricultural soil were greater than the mean values ofrnvirgin soil samples.

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