Journal of Environmental Protection, 2011, 2, 1353-1359
doi :1 0.4236/ jep.2011. 210156 Published Online December 2011 (http://www.SciRP.org/journal/jep)
1353
Measurement of Natural and Artificial
Radioactivity in Soil at Some Selected Thanas
around the TRIGA Mark-II Research Reactor at
AERE, Savar, Dhaka
Shawpan Chandra Sarkar1, Idris Ali2, Debasish Paul2, Mahbubur Rahman Bhuiyan3*,
Sheikh Mohammad Azharul Islam1
1Department of Physics, Jahangirnagar University, Dhaka, Bangladesh; 2Health Physics & Radioactive Waste Management Unit,
Institute of Nuclear Science & Technology (INST), Atomic Energy Research Establishment (AERE), Dhaka, Bangladesh; 3De-
partment of Physics, Comilla University, Comilla, Bangladesh.
Received October 2nd, 2011; revised November 3rd, 2011; accepted December 4 th, 2011.
ABSTRACT
The activity concentration of natural and fallout radionuclides in the soil at some selected Thanas around the TRIGA
Mark-II Research Reactor at Atomic Energy Research Establishment (AERE), Savar, Dhaka were measured by using a
high purity germanium detector (HPGe). The study revealed that only natural radionuclides were present in the sam-
ples and no trace of any artificial radionuclide was found. The average activity concentration of 238U, 232Th and 40K
were found to be 37.8 ± 5.6 Bq·kg –1, 58.2 ± 11.0 Bq·kg –1 and 790.8 ± 153.4 Bq·kg–1 respectively. The radium equivalent
activity (Req), absorbed dose rate (D), external radiation hazard index (Hex) and internal radiation hazard index (Hin)
were also calculated to find out the probable radiological hazard of the natural radioactivity.
Keywords: Natural Radionuclide, Artificial Radionuclide, HPGe Detector, TRIGA Mark-II Research Reactor, Activity
Concentration
1. Introduction
Radioactivity may be natural and artificial. Natural radio-
activity occurs due to extraterrestrial sources as well as
from radioactive elements in the earth’s crust. Significant
amount of artificial (man-made) radioactivity is emitted
by nuclear power plant, industrial plant and research fa-
cilities. A large amount of radiation releases due to acci-
dent of nuclear reactor.
Most widely spread natural radionuclides are from the
family of Uranium (238U), Thorium (232Th), Actinium
(235Ac) and Kalium (40K). Significant amount of man-
made radionuclides 137Cs and 90Sr may also present in
soil as a result of nuclear weapon testing in the atmos-
phere, accidents (such as the Chernobyl power plant ac-
cident) and the routine discharge of radionuclides from
nuclear installations [1]. 137Cs dominates among durable
artificial gamma radiators. It takes 300 year for it to
fragment completely. Due to that it migrates in various
geospheres and biological links. The biggest part of 137Cs
is accumulated in the upper layer of the soil and forest
floor [2].
The TRIGA Mark-II Research Reactor of AERE is
located at Savar of Dhaka District is a light-water-cooled
graphite reflected reactor designed for continuous opera-
tion at a steady-state power level of 3 MW. A significant
amount of lo w-level of solid , liquid and gaseous radio ac-
tive wastes are being generated fro m operation and main-
tenance of 3 MW TRIGA Mark-II Research Reactor.
Radiation may release from these waste. These radioac-
tive substance precipitated on the earth surface are either
lifted again by the wind or p enetrate into the ground. T he
radioactive substances are absorbed by plant through
their roots and finally reach human body [2].
The aim of this study is to detect the natural (238U,
232Th and 40K) and probable artificial radionuclide (137Cs)
and to determine their activity level in the soil at Some
Selected Thanas around the TRIGA Mark-II Research
Reactor at AERE, Savar, Dhaka.

Measurement of Natural and Artificial Radioactivity in Soil at Some Selected Thanas around 1354 the TRIGA Mark-II Research Reacto r at AERE, S avar, Dhaka
2. Methods and Analysis
2.1. Sample Collections and Preparation
Eighteen soil samples were collected from the four Tha-
nas (Dhamrai, Ashulia, Savar and Singair) around the
TRIGA Mark -II Research Reactor, AERE, Savar, Dhaka.
Each sample was collected maintaining a distance of
about 1 km to 5 km from each other. The soil samples
were collected at the depth of 5 cm with respect to the
surface. About 1 kg of sample was collected from each
location and each of the samples was placed in plastic
packet and transported to the laboratory. All the samples
were collected during the period of 25 October to 16
December in 2008. Each sample was segregated for stone
and grass and then dried at about 110˚C in an oven for 24
hours. The samples were then ground into fine powder
with a grinder and collected after passing through a 10-
mesh screen. T hus, homogenized sample was transferred
to sealable cylindrical plastic container of 7 cm height
and 5.5 cm in diameter, marked individually with identi-
fication parameters. The net weights of all the samples
were noted. All the sample containers were then sealed
tightly with cap and wrapped with Teflon and thick vinyl
tapes around their screw necks and finally air tightened
with polythene pack and stored for minimum four weeks
prior to counting, allowing estab lishment of secular equi-
librium between the long lived 238U, 232Th and their de-
cay products. Figures 1, 2 and 3 show the sampling loca -
Figure 1. Map showing the different locations of sample collecti on in Savar and Ashulia Thana.

Measurement of Natural and Artificial Radioactivity in Soil at Some Selected Thanas around 1355
the TRIGA Mark-II Research Reacto r at AERE, Savar, Dhaka
Figure 2. Map showing the different locati ons of sa mple collection in Dhamrai Thana.
tions.
2.2. Data Collection and Analysis
Each of the prepared samples and standard (Al2O3 based
226Ra) were placed on the top of the HPGe detector wi-
thin the shielding arrangement and counted for 10,000
seconds. The software of the HPGe detecting system pro-
vides the corresponding gamma spectra collected for both
samples and standards. Gamma ray spectrometry can be
used to identify gamma ray energies and consequently
the radioactive species which are producing them. The
area under the peak in a gamma ray spectrum represents
the number of counts collected for only that gamma ray
energy. These peak areas were used for determination of
radioactivity concentration of the radionuclides present
in the sample. The net count o f the sample is obtained b y
subtracting a linear background distribution of the pulse
height spectra from the corresponding peak energy area.
From the net counts of the samples activity concentra-
tion of the radionuclides were calculated using the for-
mula
 
r
CPS 1000
AabsI absW




 (1)
where, A is the activity concentration in Bq·kg–1, CPS is
the net peak counts per second of the samples, W is the
weight of the sample in gm, ε(abs) is the absolute ga mma
eak detection efficiency, is the absolute gam-
p

r
I abs


Measurement of Natural and Artificial Radioactivity in Soil at Some Selected Thanas around 1356 the TRIGA Mark-II Research Reacto r at AERE, S avar, Dhaka
Figure 3. Map showing the different locations of sample collecti on in Singair Than a.
ma intensity of the corresponding gamma ray energy.
Gamma rays intensities were taken fro m the literature [3].
The peak detection efficiencies were calculated from the
full energy peak detection efficiency curve plotted using
Al2O3 based 226Ra standard as shown Figure 4. The error
in the measurement have been expressed in terms of
standard deviation (2

), where

is expressed as,
12
sb
22
sb
NN
TT






(2)
where Ns is the counts measured in time Ts and Nb is the
background counts measured in time Tb. The standard
deviation 2

 in CPS was converted into activity con-
centration in Bq·kg–1 according to Equation (1).
To determine the activity concentration, the γ-ray line
Figure 4. Efficiency curve of HPGe detector.
of 351.92 keV (214Pb) and 609.31 keV (214Bi) were used
to determine 238U. The γ-ray line of 911.07 keV (228Ac)
and 583.19 keV (208Tl) were used to determine 232Th. The
γ-ray line of 1460.75 keV was used to determine 40K and
661.31 keV were used to determine 137Cs.
The radium equivalent activity (Req) in Bq·kg–1 was
calculated to compare the specific activity of the material
containing different amount 238U, 232Th and 40K usin g th e
following relation given in [4]:


1
eq RaThk
RaC1.43C0.07CBq kg

  (3)
where CRa, CTh and CK are the activity concentration of
238U, 232Th and 40K respectively.
The γ-ray absorbed dose rate (D) in nGyh–1 in air due
to the natural radionuclides 238U, 232Th and 40K was cal-
culated using the formula as reported in [1]:


Ra ThK
D 0.42C0.662C0.0432C (4)
where CRa, CTh and CK have the same meaning as Equa-
tion (3).
The soil is used for making earthen huts and bricks
have the external radiation hazard index (Hex) and inter-
nal radiation hazard index (Hin). The Hex and Hin were
calculated using the formula as given i n [1].
Ra K
ex CC
H1
370 259 4810
Th
C

  (5)

Measurement of Natural and Artificial Radioactivity in Soil at Some Selected Thanas around 1357
the TRIGA Mark-II Research Reacto r at AERE, Savar, Dhaka
Ra Th K
in CCC
H185259 4810 
where CRa, CTh and CK have the same meaning as Equa-
tion (3).
activity concentrations of 238U, 232Th and 40K
e detector. The activity
137Cs in Bq·kg–1, the radium equivalent activity (Req), absorbed
ndex (Hin) in soil samples
(6)
3. Results and Discussion
The mean
were measured by using a HPG
238
concentration of U ranged from 25.5 ± 5.4 to 64.4 ± 6
with an average value of 37.8 ± 5.6 Bq·kg–1. The activity
concentration of 232Th ranged from 40.8 ± 10.1 to 77.4 ±
11.2 with an average value of 58.2 ± 11.0 Bq·kg–1. The
activity concentration of 40K ranged from 425.1 ± 156.1
to 974.8 ± 156.4 with an average value of 790.8 ± 153.4
Bq·kg–1. Mean activity concentrations of 238U, 232Th and
40K, Radium equivalent activity (Req), dose rate (D), ex-
ternal radiation hazard (Hex), internal radiation hazard
(Hin) and range and mean values of activity concentration
are shown in the Table 1 and Table 2, respectively. The
mean activity concentrations of 238U, 232Th and 40K are
Table 1. Mean activity concentration of 238U, 232Th, 40K and
dose rate (D), external hazard index (Hex) and internal hazard i
shown graphically in the Figures 5-7, respectively.
The results of the present study showed that the acti-
vity concentration of thorium is 1.5 times higher than
that of uranium. It is also observed that the activity con-
centration of 40K is 13.5 times higher than that of thorium
and 20.9 times higher than that of uranium. The exces-
sive usage of Potassium containing fertilizers (NPKS,
MOP etc.) in the area adjacent to the sampling sites may
cont ribute to the higher value of 40K activity [1].
A comparative study was also performed for the acti-
vity concentrations in the present work with the other
studies performed in home and aboard and is shown in
the Table 3.
The activity concentrations of the radionuclides in the
soil samples of four Thanas around the TRIGA Mark-II
research reactor in Bangladesh are within the range of
values reported in the other work performed in home and
abroad.
Since no 137Cs radionuclide was detected in any of the
soil samples, it indicates that there is no fission product
Activity concentration in Bq·kg–1
Sam. ID 238U 232Th 40K 137Cs Req in Bq·kg–1 Dose rate in nGy·h–1 H
ex H in
Soil of Dh amrai Th an a
Dham-1 64.0 67.8 974.6.4 0.6 8 0.8 0
Dham-2 40.4 ± 5.8 62.7 ± 10. 8 950.6 ± 157. 5 99.7 ± 16.3 0.54 ± 0.08 0.65 ± 0.10
of A
68
il of
S
0.
0.
.4 ± 6.3 ± 108 ± 15ND228. 8 ± 32 .3 114 ± 16.3 2 ± .0 ± 0.1
ND196. 5 ± 32 .2
Dham-3 48.9 ± 5.7 72.7 ± 10. 7 934. 6 ± 15 3.9 ND218.2 ± 31 .7 10 9.2 ± 16 0.47 ± 0.08 0.73 ± 0.10
Dham-4 40.4 ± 5.2 4 9.0 ± 9.6 880. 0 ± 14 3.0 ND172.0 ± 28 .9 87.6 ± 14.6 0.48 ± 0.08 0.58 ± 0.07
Dham-5 38.8 ± 5.9 49.3 ± 10. 9 863. 5 ± 16 2.2 ND169.6 ± 32 .7 86.4 ± 16.7 0.47 ± 0.09 0.37 ± 0.10
Soil
ND
shulia Than a
180.51 ± 304 88As h- 1 39.8 ± 5.4 .5 ± 10.4 610. 8 ± 146.9 .5 ± 15.4 0.49 ± 0.08 0.6 ± 0.09
As h- 2 31.1 ± 5.5 60.8 ± 10. 7 646. 6 ± 15 4.0 ND1 6 3.2 ± 31.5 81.3 ± 15.9 0.45 ± 0.08 0.53 ± 0.1
As h- 3 27.4 ± 5.4 58 .0 ± 9.9 694. 5 ± 143.4 ND158. 9 ± 29 .5 79.9 ± 14.9 0.44 ± 0.08 0.51 ± 0.09
As h- 4 29.7 ± 5.0 47.5 ± 18. 5 639. 7 ± 13 8.8 ND1 4 2.3 ± 41.1 71.6 ± 20.2 0.395 ± 0. 1 0.47 ± 0.12
As h- 5 41.4 ± 5.9 66.7 ± 11. 2 586. 6 ± 159.8 ND177.7 ± 33 87.0 ± 16.8 0.38 ± 0.09 0.59 ± 0.1
So
ND
Sav ar Th ana
190. 7 ± 31 .5 Savar - 1 45.3 ± 5.7 73.4 ± 10. 7 579. 4 ± 15 1.1 92.8 ± 15.9 0.52 ± 0.08 0.64 ± 0.1
avar- 2 39.3 ± 5.8 77.4 ± 11. 2 425. 1 ± 156.1 ND179. 6 ± 32 .7
of S
86.2 ± 20.3 0.49 ± 0.09 0.59 ± 0.1
Soil
ND
ingair Thana
189. 1 ± 34.3 Sing-1 39.2 ± 6.1 57.6 ± 11.5 966.6 ± 16 9.1 96.5 ± 17.5 0.52 ± 0.09 63 ± 0.11
Sing-2 33.4 ± 5.4 41.9 ± 10.0 958.0 ± 1 5 0.0 ND1 6 0.3 ± 30.2 83.2 ± 15.3 0.45 ± 0.08 53 ± 0.09
Sing-3 28.1 ± 5.3 41.0 ± 10.0 856.4 ± 15 0.8 ND1 46.6 ± 30.1 75.9 ± 15.3 0.41 ± 0.08 0.48 ± 0.09
Sing-4 34.6 ± 5.3 53.0 ± 10.0 844.9 ± 14 6.7 ND1 69.4 ± 29.8 86.1 ± 15.1 0.47 ± 0.08 0.56 ± 0.09
Sing-5 33.3 ± 5.9 61.3 ± 11.5 972.8 ± 16 7.8 ND188 . 9 ± 34 96.7 ± 17.3 0.52 ± 0.09 0.61 ± 0.10
Sing-6 25.5 ± 5.4 40.8 ± 10.1 849.4 ± 15 4.9 ND1 43.2 ± 30.6 74.4 ± 15.6 0.40 ± 0.08 0.47 ± 0.09
ND: Not Detected.

Measurement of Natural and Artificial Radioactivity in Soil at Some Selected Thanas around 1358 the TRIGA Mark-II Research Reacto r at AERE, S avar, Dhaka
Fig ure 5. Mean activity concentration of 238U in Bq·kg–1 in the collected soil samples.
Fig ure 6. Mean activity concentration of 232Th in Bq·kg–1 in the collected soil samples.
Fig ure 7. Mean activity concentration of 40K in Bq·kg–1 in the collected soil samples.
spread due to the operation of the TRIGA Mark-II re-
search reactor or d
where.
the country and socio-economndition of this area is
development. The
established in this
e use of the reactor and the accidental release of
lide may greatly modify the natural radiation
ctivity concentrations of the radionu-
ue to any other nuclear sources else-improving day by day due to industrial
country’s only Research Reactor is
4. Conclusions
The Savar region is one of the most populated regions in
area. Th
radionuc
ic co
environment. The a

Measurement of Natural and Artificial Radioactivity in Soil at Some Selected Thanas around 1359
the TRIGA Mark-II Research Reacto r at AERE, Savar, Dhaka
ns Table 2. Rang e and mea n value of activit y concentrat ioof 238U, 232Th, 40K and 137Cs in Bq·kg–1 of the samples.
Radionuclide Minimum Maximum Mean
238U 25.5 ± 5.4 64.4 ± 6 37.8 ± 5.6
232Th 40.8 ± 10.1 77.4 ± 11.2 58.2 ± 11.0
40K
137
421 97790.3.4 5.1 ± 15 6.4.8 ± 15 6.4 8 ± 15
Cs ND ND ND
Table 3.n of the present st udork.
ion 232Th 40K Rces
Comparisoy with other w
Locat 226 Ra eferen
Around TRIGA k-II (Bangladesh) 3 5.6 58.2 ± 11.0 790.8 ± 153.4 sent Study Mar7.8 ±Pre
Louisiana (Soi l), USA 729 [5]
Irakia (reece 212 (5) 43 (6) 1130 (4 2464)
Chh
43 - 95 50 - 190 43 -
sand), G24 - 7618 - 664 -[6]
Nile Delta, Egypt 17 - 316 [7]
Jes sore, Bang lades h 48 ± 9 53 ± 9 481 ± 78 [1]
Nigeria 8.3 ± 2.6 34.3 ± 3.4 684 ± 7.3 [8]
ittag o ng, Bang lades34 .6 60 438 [9]
Peshwar, Pakistan 65 84 646 [10]
clides in the soples are in the range ovalues
reported but the activitvels are
slightly hirmissible activity ls which
re in general 41.0, 52.2 and 230 Bq·kg–1 for 238U, 232Th
s in Surface Soil and Bottom Sedi-
ment in the Dladesh and Evalua-
tion of Radiatf Bangladesh Aca-
ian, M. Kamali, M. Mostajabod-
[ Delaune, G and C. J. Smith. “Radinu-
des Concentrationsouisiana Soils andiments,”
alth Physics, Vol. o. 2, 1986, pp. 23.
[6] G. Trabidou, H. Florou, A. Angelopoulos and Sakelliou,
bd e l Gha n i , S . M. Ahaw k y, E . M.
il samf the
in other countries,y le
gher than the peleve
a
and 40K respectively [11]. Further, the results of the pre-
sent study would be useful as a base line data of the re-
gions under study and also help as a guideline for the
competent authority (Bangladesh Atomic Energy Com-
mission) to go forward to fix up the dose limit for the
radiation protection activities of the country and in the
academic activities of the health physics, geophysics and
environmental science.
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