Kakolee et al./ JnUJSci., Vol. 08, No. I, Dec. 2021, pp.

5965 59

Measurement of Natural Radioactivity due to 226Ra, 232Th and 40K in Soil

at Chandpur District, Bangladesh

Research Article
1* 2 1 2 2
K. F. Kakolee , S. Pervin , Md. Shahabuddin M.M.M. Siraz and S. Yeasmin
1
Department of Physics, Jagannath University, Dhaka, Bangldesh
2
Heath Physics Division, Atomic Energy Centre Dhaka, Bangladesh.

Received: 18 August 2021

Accepted: 15 December 2021

Abstract: Ffifteen soil samples, collected from Chandpur district, Bangladesh, have been studied and radioactivity of
226
Ra, 232Th and 40K were identified. Gamma-ray spectrometry system was employed to perform the
measurements. With the help of a high purity germanium (HPGe) detector, the average radioactivities of
226
Ra, 232Th and 40K in the collected soil samples have been calculated respectively 24.81±0.040408
Bq/kg, 18.97±0.03769 Bq/kg and 398.82±0.3534962 Bq/kg.

Keywords: Activity concentration of soil  Health hazards in Chandpur district

I. Introduction The objective of this work is to find out the radiation

Radiations are omnipresent in the environment since level of environment in Chandpur district. Measurements
the big bang occurred. We the people and our foods are of the radioactivity of the radionuclides in soils, waters,
always exposed to different types of natural radiation plants and air of a region can help to determine the
which can be originated from diverse sources, like radioactivity level. Therefore, analysis of soil has a great
cosmic, terrestrial and natural decay series of radioactive
significance. Choosing the Chandpur district has some
nuclides (Dinh et al., 2011). A most important source for
explicit reasons. It is a quite important district in our
natural radioactivity is soil and considered as one of the
main source for radiation-hazard interritory. So soil’s country. It is situated at the meeting point of three big
natural-radioactivity is well-thought-out as a basic rivers (Dakatia, Meghna and Gomoti) of the country. A
indicator for radiological contamination (Rahman and huge number of national fish Hilsha was found in the
Faheem, 2008). Some vital primeval radionuclides are of rivers of this district. So, if the radioactivity of this area’s
238U-series (half-life, t1/2 = 4.47 × 109 yrs), 232 Th- soil exceed the hazardous limit (suggested by the NSRC
series (t1/2 = 1.41 × 109 yrs) and 40K (t1/2 = 1.28 × 109 (nuclear safety and radiation control) Rules -1997,
yrs) (UNSCEAR, 1993). 232Th is the first elemental Bangladesh), then not only the large population of this
isotope of thorium with copiousness of 100% on earth. district will be in danger but also whole country will be at
40
K can be found in human, animal, soil and in the oceans
high health risk as vegetables, foods that are grown
with different concentrations. The copiousness of40Kon
inside this district are frequently transported to other
earth is around 0.012 % (Environmental Science
Division, 2010). parts of the country.

*Corresponding Author: K. F. Kakolee

Email: [email protected]
59
60 Measurement of Natural Radioactivity due to 226Ra, 232Th and 40K in Soil at Chandpur District, Bangladesh

2. Experiment 2.2 Preparation of Soil Samples

If sample preparation is not done appropriately then it
can be a big source of inaccuracies which must implies
defect in the scientific results. Therefore deep care was
taken for every sample to avoid impurity. All the samples
were collected during the month of August in 2019. The
collected soil samples were first dried in air for 2-3 days
Figure 1. Block diagram of gamma spectroscopy system as august is a month of monsoon. Dried soil samples
(HPGe detector) were heated up by an electric oven at 110oC for twenty
four hours and placed inside an electric furnace thereafter
In this study, spectral analysis of the fifteen soil samples
at 350 oC for 48 hours. This process transform the
has been performed in Atomic Energy Centre Dhaka
leftover plants to ash. All the samples were then pressed
(AECD) using a gamma spectrometer equipped with high
through a mesh of 2 mm in size to obtain a homogenous
purity germanium detector (HPGe). The equipment sample matrix (IAEA, 1989). An electronic balance was
engaged in this gamma-ray spectrometry (UNSCEAR used to weigh the samples. Lastly each samples were
Annex, 2000a) include an energy-sensitive radiation sealed in different plastic containers for a month before
detector named high purity germanium detector (HPGe), gamma spectrometry.
high voltage power supplier, multichannel analyzer,
Table 1: GPS location of the source of soil sample.
amplifiers and computer. The quantitative study of the
energy spectra of gamma-ray sources is done by means of Sl Name of Sample ID Lattitude Longitude
Gamma-ray spectroscopy. Some familiar sources of locality
gamma ray are nuclear laboratory and nuclear process and 01. Badda Soil-01 23.277847N 90.861704E
other radiation measurement contexts. Most of the 02. Badamtali Soil-02 23.281506N 90.873024E
radioactive sources emit gamma rays with different
03. Bawra Soil-03 23.285112N 90.869212E
characteristics such as energy and intensity. When gamma
emissions are analyzed with a gamma-ray spectrometer, 04. Nischintopur Soil-04 23.285072N 90.857163E
gamma energy spectra are produced. Figure 1 gives the 05. Suhilpur Soilpur-05 23.291765N 90.834013E
block diagram of gamma spectroscopy whereas Figure 2
06. Kalocho Soil-06 23.299565N 90.895421E
gives the pictorial view of experimental set up.
07. Belghar Soil-07 23.281841N 90.873281E
08. Nowapara Soil-08 23.282527N 90.873950E
09. Sihircho Soil-09 23.289654N 90.845655E
10. Sarashia Soil-10 23.281498N 90.862905E
11. Kazirgaw Soil-11 23.277956N 90.859744E
12. Goureshor Soil-12 23.312152N 90.894562E
13. Khakbaria Soil-13 23.275898N 90.835636E
14. Dhadda Soil-14 23.301256N 90.856425E
15. Matain Soil-15 23.265782N 90.845326E

Figure 2. Photograph of laboratory setup for

radioactivity measurement.

2.1 Sample Collection

All the samples were collected from Hajigonj upazilla of
Chandpur district. Fifteen soil samples from different
area were collected. Samples were marked by Global
Positioning System (GPS) for each respective
locationsTable.1 gives the positioning information of the
soil samples which can be used for referencing.. Samples
were then numbered and taken into the laboratory for
dealing out. Figure 3. Collection of samples from study area.
 Kakolee et al./ JnUJSci., Vol. 08, No. I, Dec. 2021, pp. 5965 61

here, ARA, ATh and Ak are the specific activities of 226Ra,

232
Th and 40K in Bq/kg.

2.6 Health Hazard Indices

Soil is also be used for housing. Thus it might contribute
to the external health hazard to human being. The
radiation dose rate due to the external exposure of
gamma radiation in materials is termed as the external
hazard index (Hex) (Lu and Xiolan, 2006) and can be
estimated as follows
Hex = ARa/370 + AK/4810+ ATh /259 (2.4)
The internal hazard index (Hin) gives the internal exposure
Figure 4. Sample prepared for measurement
to carcinogenic radon and its short-lived daughter nuclide,
can be obtained with the help of equation 2.5 [69]:
2.3 Activity Calculation
Each samples were put on top of the HPGe detector and Hin= ARA/185 + ATh /259 + Ak/4810 (2.5)
counted for 10,000 seconds. The software of the HPGe Here ARA, ATh and Ak have same meanings as in equation
detecting system provides the respective gamma spectra (2.3). To keep the radiation hazard trivial, value of Hex
for each samples. By subtracting a linear background should be lower than unity.
distribution for a pulse spectra from corresponding peak
energy area, net amount of the sample were obtained. 3. Result And Discussion
Using the following equation the net counts activity of The activity concentrations of different radioactive
the each samples has been calculated nuclides have been measured using gamma spectrum.
Measured activity concentration of 238U, 226Ra, 232Th from
(2.1) their progeny nuclides which consist of daughter nuclides
Where, A= activity of the soil sample in Bq/Kg, [214Pb (295.2 keV), 214Pb (351.9 keV), 214Bi (609.3 keV),
214
Counts per second (CPS), Ε stands for gamma Bi (1120.2 keV)] and [212Pb (238.6 keV), 208Tl (583.1
energy counting efficiency, Pγ is the absolute gamma keV), 228Ac (911.2 keV), 228Ac (968.9 keV)] respectively.
ray intensity and w = net weight of sample in gm. 3.1 Activity Concentration of Radionuclides in fifteen
2.4 Equivalent Activity of Radium samples
The distribution of226Ra, 232Th and 40K are not The following table shows the activity concentration of
homogeneous in every location of soil. The reason of this radionuclides (using equation 2.1) in each samples.
inhomogeneous distribution is disequilibrium between Table 2. Activity Concentration of radio-nuclides.
226Ra and its decay products. For uniformity in
Sample 226-Ra Th-232 K-40
exposure, the radionuclide concentrations are defined in
terms of ‘Radium equivalent activity’ (Raeq) in Bq/kg.
ID Bqkg-1 Bqkg-1 Bqkg-1
According to Beretka and Mathew (Beretka and Mathew, 1 26.62 24.54 350.70
1985) equivalent activity of Radium (Raeq) is the 2 22.91 15.10 261.99
specific activity of materials comprising of different 3 18.85 15.59 400.00
amounts of 226-Ra, 232-Th and 40-K,were calculated 4 29.58 13.77 398.00
here with the help of equation 2.2: 5 21.30 26.57 259.64
Raeq = ARA + 0.077 AK +1.43 ATh (2.2) 6 31.05 20.83 665.07
226
Here ARa, ATh and AK are the specific activities of Ra, 7 32.82 15.90 133.95
232
Th and 40K, respectively in Bq/kg. 8 29.73 21.44 401.76
2.5 Absorbed Dose Rate 9 27.17 21.75 539.07
The absorbed dose rate in air, which originate from 10 22.13 12.03 155.75
radioactive sources in the soil is a measure of the effects 11 26.18 19.42 328.04
of gamma radiation. The absorbed dose rate in air, 1 12 21.56 15.26 224.48
meter above the ground surface due to the radionuclides 13 20.66 26.54 635.88
238
U, 232Th and 40K was assessed by the help of equations
in UNSCEAR 1993 (UNSCEAR Annex, 2000b). 14 25.39 16.90 808.71
15 16.21 19.00 419.31
D(n/Gyh)=0.462ARA+0.042Ak+0.604ATh (2.3)
Average 24.81 18.97 398.82
62 Measurement of Natural Radioactivity due to 226Ra, 232Th and 40K in Soil at Chandpur District, Bangladesh

The activity concentrations of 226Ra, 232Th and 40K in the soil The minimum and maximum absorbed dose in the air are
samples were varied from 16.21Bq/kg to 32.82 Bq/kg,13.77 23.99106 and 55.66865 nGyh-1 respectively and average
Bq/kg to26.54 Bq/kg and 155.75 Bq/kg to Bq/kg respectively. value is 39.5599nGyh-1, whereas the population weighted
n soil sample for world, the average value of 226Ra, 232Th and average of absorbed dose in air is 59 nGyh-1.The
40
K are 32Bq/kg, 45Bq/kg and 420Bq/kg respectively
minimum and maximum values of Radium equivalent
(Debertin and Helmer, 1988). Figure 5 shows a graphical view
of activity concentrations of radionuclides in samples. activity are 51.337118 and 112.0574921 Bq/kg and the
average value of Radium equivalent activity is 82.66682
Concentration of Radionuclides 226Ra Bqkg-1 whereas average value for the world is 370 Bq/kg
Activity concentration Bqkg-1

900 Th-232 as recommended by IAEA (UNSCEAR Annex, 200c).

800
700 K-40 Graphical representations of radium equivalent activity
600 and absorbed dose rate in air have been shown in Figure
500
6 and 7 respectively:
400
300
200

Radium Equivalent activity Bq/kg-1

100
120
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 100
Sample code 80

Figure 5. Graphical Representation of activity 60

concentration of natural radionuclides. 40
20
3.2: Radium Equivalent Activity (Raeq)
0
The following Table 3 shows the calculated value for 1 2 3 4 5 6 7 8 9 10111213141516
Radium Equivalent Activity (equation 2.2) and absorbed Sample code
dose rate in air (equation 2.3).
Table 3. Radium Equivalent Activity and Absorbed dose Figure 6. Graphical representation of radium equivalent
rate for all samples. activity in all samples.
Sample Radium equivalent Absorbed dose
number activity (Raeq) Bq/kg rate (D) nGyh-1
1 88.723173 41.74777 D(nGy/h)
60
2 64.680113 30.63148
Absorbed Dose rate nGyh-1

50
3 71.9497 34.80783
40
4 79.93082 38.58575
5 79.305609 36.72393 30
6 112.0574921 54.66447 20
7 65.887528 30.35924 10
8 91.3385764 43.44462
0
9 99.786967 48.17157 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
10 51.337118 23.99016 Sample code
11 79.21683 37.50713
12 60.682424 28.54543 Figure 7. Graphical representation of Absorbed Dose
rate in all samples.
13 107.588789 52.09742
14 111.844964 55.66865 3.3 Hazard Index
15 75.665869 36.4497
Table 4 shows data for External hazard index (obtained
Min 51.337118 23.99016 by using equation 2.4) and Internal hazard index
Max 112.0574921 55.66865 (obtained by using equation 2.5):
Average 82.66682 39.5599
 Kakolee et al./ JnUJSci., Vol. 08, No. I, Dec. 2021, pp. 5965 63

Table 4. Data for External and Internal hazard index.

External Hazard H(ex)
Sample External hazard Internal hazard

External hzard index nGyh-1

0.35
code index(Hex)nGyh-1 index(Hin)nGyh-1
0.3
1 0.23962 0.311571 0.25
2 0.174698 0.236617 0.2
3 0.194315 0.245277 0.15
4 0.215893 0.295861 0.1
0.05
5 0.214183 0.271775 0
6 0.302639 0.386583 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
7 0.177985 0.266696 Sample code
8 0.246695 0.327068 Figure 8. Graphical representation of external hazard.
9 0.269498 0.342947
Internal Hazard Index

Internal hazard index nGyh-1

10 0.13867 0.198503 0.5
11 0.21395 0.284713
0.4
12 0.163901 0.222186
0.3
13 0.290546 0.346402
14 0.30205 0.370697 0.2
15 0.204342 0.248153 0.1
Min 0.13867 0.198503
0
Max 0.302639 0.386583 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Average 0.223268 0.290339 Sample code
The indexed value of external and internal hazard should Figure 9. Graphical representation of internal hazard
be less than unity in order to keep the radiation hazard index in all samples
insignificant .Here the average values of hazard index in
all samples are lower than the safety margin .The 3.4 Comparison with previous works
obtained average value of internal and external hazard A comparative study has been done for activity
index are 0.29 and 0.223 nGyh-1 respectively which are concentrations in soil sample with other studies
less than unity which indicate non-hazardous for human performed in Bangladesh and abroad, as shown in Table
being and environment. The graphical representation of 5. This comparison shows that the radioactivity level in
external and internal hazard index have been shown in soil in other parts of Bangladesh and around the world is
Figures 8 and 9 respectively. comparable with present study.
Table 5. Comparison with previous works in other regions.
Radioactivity concentration (Bqkg-1)
Country/Region Radionuclides References
226 232 40
Ra Th K
Chandpur, BD 24.81±0.040408 18.97±0.03769 398.82±0.35349 Present
Satkhira, BD 35.71 ± 3.92 54.06 ± 3.45 = 580.6 ± 71.63 (Hossen and Ferdous, 2015)
Savar, Dhaka, BD 23.31 42.24 733.19 (Foisal et al. 2014)
Dinajpur, BD 36.7 1 59.7 1.7 282.5 2.3 (Rahman et al., 2013)
Rooppur, BD 30.85 ± 3.42 40.88 ±5.17 521.65± 28.35 (Ferdous et al., 2013)
Rainforest Sites in Western Ghats, BD 26.26 ± 9.1 53.61 ± 10.4 204.08 ± 30.4 (Manigandan and Natrrajan, 2014)
West Bank, Palestine 41.4 19.5 113.3 (Samreh et al., 2014)
Chakwal, Pakistan 34.27 ± 1.28 51.59 ± 2.73 606.42 ± 21.23 (Rahman et al., 2018)
Kirkuk-IRAQ 27.4 to 57 11.0 to 25.4 207.4 to 516.0 (Taqi and Sarker, 2028)
Kuala Krai district, Malaysia 40.2-264.0 49.2-312.9 491.1-1184.2 (Hamzah et al., 2011)
Tamil Nadu, India 42.9 9.4 14.7 1.7 149.5 3.1 (Senthilkumor et al., 2010)
Nigeria 12.90 0.02 45.56 0.01 250.00 0.02 (Felix et al., 2016)
South Konkan , Maharashtra , India 44.97 1.22 59.70 2.17 217.51 8.75 (Joel et al., 2014)
north Jeddah west, Saudi Arabia 44.87 54.59, 2652.30 (Dhawal et al., 2014)
Kisii Region, Kenya 38.6 to 271.7 431to 360 245 to 1780 (Safia, 2014)
64 Measurement of Natural Radioactivity due to 226Ra, 232Th and 40K in Soil at Chandpur District, Bangladesh

4. Conclusion UNSCEAR Annex (2000b), Sources and Effects of

Activity concentrations of radionuclides were Ionizing Radiation, United Nations Scientific
investigated in this study. The maximum values of Committee on the Effects of Atomic Radiation.
activity concentrations of 232Th, 226Ra, and 40K were United Nations, New York, USA, (2000).
found to be 13.77 Bqkg-1 to26.54 Bqkg-1, 16.21Bqkg-1 to Anne.
32.82 Bqkg-1 and 155.75 Bqkg-1 to 808.71 Bqkg-1 Lu. X. And Xiolan. Z. (2006). Measurement of natural
respectively. The mean values are 24.81±0.040408 radioactivity in sand samples collected from the
Bq.kg-1, for 226Ra, 18.97±0.03769 Bq.kg-1 for 232Th and Booje Weithe sand park, China, Environ. Geol.
398.82±0.3534962 Bq.kg-1 for 40K respectively. 50: 977-988.
The Radium equivalent activity (Raeq) of soil samples for Debertin. K and Helmer. Gammand. R.G (1988). X-ray
Chandpur district is varied from 51.337118Bqkg-1 to spectrometry detectors, North Holland,
112.0574921 Bqkg-1 and the average value of Radium UNSCEAR Annex (2000c), Sources and effects of
equivalent activity (Raeq) is 82.66682 Bqkg-1. The ionizing radiation, Report of the Untied Nations
minimum and maximum absorbed dose in the air are Scientific Committee on the Effects of Atomic
23.99106 nGyh-1 and 55.66865 nGyh-1 respectively and Radiation to the General Assembly, United
average value is 39.5599nGyh-1. The values of external Nations, New York, USA
hazard (Hex) in these samples ranged from 0.13867 nGyh-
1
to 0.302639nGyh-1 with a mean value 0.223268nGyh-1. Hossen M. A. and Ferdous N., (2015). Determination of
The values of internal hazard (Hin) in the samples ranged Radiological Hazards and the Transfer Factors
from 0.198503nGyh-1 to 0.386583nGyh-1 with a mean of Radionulides from Soil to Vegetables in the
value 0.290339nGyh-1.Here both internal and external Southwestern District of Bangladesh Journal of
hazard index are not more than the unity for soil samples. Physical Science, 26(1): 83–98.
t is matter of relaxation that there were no artificial Faisal B. M. R., Haydar M. A., Ali M. I., D. Paul, R. K.
radionuclides .As the obtained values are within the Majumder, M. J. Uddin (2014). Assessment of
limits suggested by NSRC -1997 rules of Bangladesh and Natural Radioactivity and Associated Radiation
International Atomic Energy Agency (IAEA) so it is Hazards in Topsoil of Savar Industrial Area,
clear that the radiation level in soil of Chandpur district Dhaka, Bangladesh Journal of Nuclear and
does not pose any health risk currently. Particle Physics, 4(4): 129-136.
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