| dc.description.abstract | This study was designed to determine radiological hazard levels in soil, mine tailings and
rock samples from Agata, Okame, Busia 90 and Greenstone Resource Limited Gold
mines in Busia District. The specific activity of the radionuclides were determined using
Nal (Ti) scintillation detector and the values were then used to determine the radiological
hazard parameters due to radionuclides in the samples from the mines under study.
The specific activity of 238U in soil, mine tailings and the rock samples from the four gold
mines ranged from 18.7 Bqkg-1 to 27.9 Bqkg-1
, 7.4 Bqkg-1 to 13.2 Bqkg-1 and 1.7 Bqkg-1
to 27.8 Bqkg-1 respectively. The specific activity of 232Th in soil, mine tailings and rock
samples from the mines ranged from 60.8 Bqkg-1 to 98.8 Bqkg-1
, 25.1 Bqkg-1 to 32.7
Bqkg-1 and 2.3 Bqkg-1 to 66.6 Bqkg-1 respectively while that of4°K in soil, mine tailings
and rock samples ranged from 53.6 Bqkg-1 to 211.8 Bqkg-1
, 5.7 Bqkg-1 to 217.3 Bqkg-1
and 2.1 Bqkg-1 to 120.1 Bqkg-1 respectively. The Specific activity values of 232Th in soil
sample from each of the four gold mines were above the worldwide average value of 30
Bqkg-1
. It is only Greenstone mine tailings and Okame rocks that had higher activity for
232Th than the world wide average value. The Absorbed Dose rates in soil, rock and mine
tailings samples ranged from 41.7 nGyh-1 to 76.3 nGyh-1
, 13.3 nGyh-1 to 32.7 nGyh-1 and
2.3 nGyh-1 to 58.0 nGyh-1 respectively. Only Okame had a higher value for soil than the
world wide average value of 60 nGyh-1
• The Annual Effective Dose rates in soil, mine
tailings and rock samples ranged from 0.051 mSvy-1 to 0.093 mSvy-1
, 0.024 mSvf1 to
0.050 mSvf1 and 0.011 mSvy-1 to 0.047 mSvf1 respectively which were lower than the
ICRP recommended value of 20 mSvf1
• The internal hazard indices in soil, mine tailings
and rock samples ranged from 0.30 to 0.56, 0.15 to 0.27 and 0.02 to 0.43 respectively.
External hazard indices of the radionuclides in the soil, mine tailings and rock samples
ranged from 0.27 to 0.47, 0.10 to 0.23 and 0.01 to 0.36 respectively. They were found to
be below unity as per ICRP, 2007 maximum permissible limit. The Excess Lifetime
Cancer Risk (ELCR) ranged from 6.90x10-5 to 1.93x104 was lower than the ICRP
maximum permissible excess lifetime cancer risk limit of 5.60x10-2
. Despite the low
radiological health risk, miners need protective gears particularly at Okame and
Greenstone mines and further research need to be done to validate these findings. | en_US |
