ASSESSMENT OF RADIOACTIVITY CONCENTRATION AND RADIATION HAZARDS INDEX FOR BUILDING MATERIALS USED IN BABADOGO ESTATE, NAIROBI CITY COUNTY, KENYA
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Date
2022-05
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Abstract
Natural radioactive materials in certain conditions can get to hazardous radiological
level. Some of these hazards are not prone to control as well as, they are usually
referred to as the background radiation. The aim of my research work is to evaluate
natural radioactivity concentration and radiological impacts on representative sampled
building materials collected from different locations in Babadogo estate within Nairobi
City County. The selected samples were crushed, sieved dried and store for four weeks
after which, analysis done using gamma ray spectrometer was put into action for
spectral data acquisition then analysis. The activity concentration levels of 238U, 232Th
and 40K for the selected samples of building materials was measured by the use of
gamma- ray spectrometry method. Radiological parameters were evaluated based on the
prerequisite activity concentration obtained. The analyzed data compared with the
standard acceptable values. The activity concentration in 40K varied from 55±3 to
2647±132 Bq/kg giving average value of 831 ±42 Bq/kg,
238U varied from 39±2 to
3602±180Bq/kg giving average figures of 378±19Bqkg¯1
and 232Th ranged from
5.000±0.300 to 4213±211Bqkg¯1
giving mean figure of 290±15Bq/kg . Calculated
mean figures for activity concentration surpassed the world mean figures of 420Bq/kg,
33Bq/kg, 45Bq/kg in 40K, 238U and 232Th respectively. Absorbed dose rate calculated
ranges between 73±4 and 4777±239nGyh¯1
having average value of 540±27nGyh¯1
.The mean number for the absorbed dose rate was above the world acceptable mean
value of 54nGyh¯1
. The calculated annual effective dose rate varied from
0.040±0.002mSvy¯1
to 2.340±0.117mSvy¯1
having average figure of
0.260±0.013mSvy¯1
,which was above the world average of 0.070mSvy¯1
but below the
maximum dose constraint of 1mSvy¯1
.These results show that building materials in
Babadogo estate are safe and can be used for construction of buildings and thus can be
continued using as further research is done on other building materials not covered in
my research work.