You need JavaScript to view this

Radiochemical studies on environmental radioactivity in Sudan

Abstract

Measurements of uranium and thorium isotopes, {sup 226} Ra, {sup 210} Po, {sup 228} Ra, {sup 40} K and fallout radionuclide {sup 137} Cs in soil samples collected from different districts in Sudan, rock phosphate samples collected from the uro and kurun rock phosphate deposits in the eastern part of the Nuba mountains in Western Sudan, and surface marine sediments and marine organisms collected from the sudanese coastal waters of the Red Sea have been made using a high resolution gamma-spectrometry, radiochemical separation and {alpha} spectrometry. The external exposure due to {gamma} radiation from the ground has been calculated. The average exposure was found to be 45.4 {+-} 21.3 nGy/h, corresponding to the annual dose equivalent of 278 {mu}Sv/y. With the exception of some areas, the calculated exposure falls within the global wide range of outdoor radiation exposure given in the UNSCEAR publications. The nation-wide average concentrations of {sup 226} Ra, {sup 238} U, {sup 232} Th, {sup 40} K and {sup 137} Cs determined were 31.6 {+-} 27, 20.1 {+-} 16.4, 19.1 {+-} 8.1, 280.3 {+-} 137.6 and 4.1 {+-} 4.3 Bq/Kg, respectively. This shows that there is little contamination due to fallout radioactivity at survey sites. The exchangeable  More>>
Authors:
Sam, Adam Khatir [1] 
  1. Sudan Atomic Energy Commission, Khartoum (Sudan)
Publication Date:
Sep 01, 1998
Product Type:
Miscellaneous
Report Number:
INIS-SD-020
Reference Number:
SCA: 400101; PA: AIX-29:048418; EDB-98:101401; SN: 98002001269
Resource Relation:
Other Information: DN: 189 refs. , 33 tabs. , 17 figs.; TH: Thesis (Ph.D.); PBD: 1998
Subject:
40 CHEMISTRY; ALPHA SPECTROSCOPY; GAMMA SPECTROSCOPY; NUMERICAL DATA; SEDIMENTS; THORIUM; URANIUM
Sponsoring Organizations:
Sudan Atomic Energy Commission, Khartoum (Sudan); International Atomic Energy Agency, Vienna (Austria)
OSTI ID:
651329
Research Organizations:
Sudan Atomic Energy Commission, Khartoum (Sudan)
Country of Origin:
Sudan
Language:
English
Other Identifying Numbers:
Other: ON: DE98634541; TRN: SD9800007048418
Availability:
INIS; OSTI as DE98634541
Submitting Site:
INIS
Size:
183 p.
Announcement Date:

Citation Formats

Sam, Adam Khatir. Radiochemical studies on environmental radioactivity in Sudan. Sudan: N. p., 1998. Web.
Sam, Adam Khatir. Radiochemical studies on environmental radioactivity in Sudan. Sudan.
Sam, Adam Khatir. 1998. "Radiochemical studies on environmental radioactivity in Sudan." Sudan.
@misc{etde_651329,
title = {Radiochemical studies on environmental radioactivity in Sudan}
author = {Sam, Adam Khatir}
abstractNote = {Measurements of uranium and thorium isotopes, {sup 226} Ra, {sup 210} Po, {sup 228} Ra, {sup 40} K and fallout radionuclide {sup 137} Cs in soil samples collected from different districts in Sudan, rock phosphate samples collected from the uro and kurun rock phosphate deposits in the eastern part of the Nuba mountains in Western Sudan, and surface marine sediments and marine organisms collected from the sudanese coastal waters of the Red Sea have been made using a high resolution gamma-spectrometry, radiochemical separation and {alpha} spectrometry. The external exposure due to {gamma} radiation from the ground has been calculated. The average exposure was found to be 45.4 {+-} 21.3 nGy/h, corresponding to the annual dose equivalent of 278 {mu}Sv/y. With the exception of some areas, the calculated exposure falls within the global wide range of outdoor radiation exposure given in the UNSCEAR publications. The nation-wide average concentrations of {sup 226} Ra, {sup 238} U, {sup 232} Th, {sup 40} K and {sup 137} Cs determined were 31.6 {+-} 27, 20.1 {+-} 16.4, 19.1 {+-} 8.1, 280.3 {+-} 137.6 and 4.1 {+-} 4.3 Bq/Kg, respectively. This shows that there is little contamination due to fallout radioactivity at survey sites. The exchangeable radium fraction constitutes 19-24% of the total radium content. The data show that {sup 238} U and its decay products are the principal contributors of radioactivity in both phosphate deposits at Uro and Kurun. The equivalent mass concentrations of uranium in the Uro rock phosphate fall within the range that could be economically recovered as the by-product of fertilizer industry. The mean activity concentrations weighted by average agricultural consumption of 300 kg/ha of untreated ground rock fertilizer resulted in an annual distribution of 120.63 Bq Ra/m{sup 2} with Uro rock and 12.97, 0.21 and 4.24 Bq/m{sup 2} respectively, with Kurun rock fertilizer. The external radiation exposure over agricultural areas was estimated 23.41 x 10 {sup -9} Gy/h and 2.59 x 10 {sup -9} Gy/h at 1 m above ground level for Uro and Kurun rock phosphate fertilizers, respectively. In marine sediments analyzed, the maximum activity concentrations of {sup 238} U, {sup 226} Ra, {sup 210} Po, {sup 232} Th, {sup 40} K and {sup 137} Cs were found to be 53, 59.9, 94.7, 19.3, 515 and 10.1 Bq/kg dry weight, respectively. Comparison of the data on natural radionuclides from coastal marine sediments with those collected from 30 km off-shore (Sanganeb atoll) reveals that both anthropogenic and terrestrial influx from the hinterland into the data is negligible. However, values for {sup 236} Ra and {sup 210} Po are higher in the sediments from Port Sudan harbour relative to those from the adjacent fringing reefs. Uranium content is higher in shallow-water sediments and the authigenic fraction constitutes 12% on the average. The {sup 228} Th/{sup 232} Th disequilibrium in sediments indicates a rapid rate of sedimentation at the sampling sites. The activity levels detected for {sup 137} Cs in sediments collected from the Port Sudan harbour are fairly high as compared with the values from other sampling areas. On the basis of individual data, the variations are insignificant with regard to the uptake of natural radionuclides by marine species considered in this study. However, {sup 137} Cs activity in algae ranged from 0.33 to 1.32 Bq/kg with Sargassum (brown algae) showing the highest level. 189 refs. , 33 tabs. , 17 figs.}
place = {Sudan}
year = {1998}
month = {Sep}
}