Examining External Dose Rates in Mamuju Regency, Indonesia: A
Personal Radiation Dosimetry Approach
Rakotovao Lovanantenaina Omega1, Adi R.A.Abdullah1, Sidik Permana1,2,3,4,
Wahyu Srigutomo4, Alan Maulana5, Haryo Seno5, Ismail Humolungo2,
3 & Rahmi Elzufiah3
\\\\Jalan\\
Fungki Iqlima Nasyidiyah2, Zulfahmi3, Frafti Rejeki
1

Doctoral Program in Nuclear Engineering Department, Institut Teknologi Bandung, Jalan Ganesa No. 10,
Bandung 40132, Indonesia.
2
Master Program in Nuclear Science and Engineering Department, Institut Teknologi Bandung,
Jalan Ganesa No. 10, Bandung 40132, Indonesia.
3
Master Program in Physics of Teaching Department, Institut Teknologi Bandung, Jalan Ganesa No. 10, Bandung,
Indonesia
4
Physics Department, Institut Teknologi Bandung, Jalan Ganesa No. 10, Bandung 40132, Indonesia.
5
Indonesia’s National Research and Innovation Agency, Jalan Tamansari No. 71, Bandung 40132, Indonesia
*Corresponding author: psidik@itb.ac.id

Abstract
This study aimed to quantify the individual external radiation exposure in Mamuju, Indonesia. A SmartRad portable personal
dosimeter was utilized for this purpose, and data was collected over a period of 30 days. The findings indicate that the dose
rate varies from 0.152 to 4.200 μSv/h and cumulatively ranges from 0.1 to 8.4 μSv/day based on an average measurement
duration of 160 minutes. The average dose rate in areas with mineral deposits is 11.02 mSv per year. In contrast, the average
effective dose in areas without radioactive mineral deposits is 2.6493 mSv per year. The annual average effective dose for
individuals was measured at 6.8347 mSv. These findings imply that personal exposure to radiation among the public in
Mamuju exceeds the threshold recommended by the International Commission of Radiological Protection.
Keywords: Mamuju; natural radiation; radioactive mineral; radiation protection; radiation exposure.

Introduction
Mamuju, a region in Indonesia, has been identified as a unique high natural background radiation area (HNBRA).
The area is known for its high radiation exposure compared to the average across the country. Massive
radioactive mineral deposits contribute to the high levels of natural radiation in the region. The primary
radioactive elements in the earth’s crust that lead to human exposure are potassium ( 40K), uranium (238U),
thorium (232Th), and their radioactive decay products, e.g., radium ( 226Ra ) and radon (222Rn). 226Ra, a byproduct
of the decay process of uranium and thorium, is a radioactive element that can be found in the environment
and can potentially lead to adverse effects on human health when existing in drinking water. This element has
the potential to infiltrate groundwater from natural deposits present in the earth’s crust. When humans
consume water contaminated with radium, a significant portion of it, approximately 80%, is expelled from the
body through waste products. However, the remaining 20% is absorbed and distributed throughout the body,
primarily accumulating in the bones.
The ingestion of radium, particularly through drinking water, is of concern due to the alpha particles it emits,
which can cause tissue damage. This damage can result in a range of health complications, such as anemia,
cataracts, dental fractures, inhibited bone growth, compromised immunity, and in severe cases cancer. The
severity of these health effects is influenced by the level and frequency of radiation exposure as well as the
specific type of radium ingested.

Copyright ©2023 Published by IRCS - ITB
ISSN: 2337-5779

J. Eng. Technol. Sci. Vol. 55, No. 6, 2023, 681-688
DOI: 10.5614/j.eng.technol.sci.2023.55.6.6

Research Paper

Journal of Engineering and Technological Sciences

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Rakotovao Lovanantenaina Omega et al.

The yearly radiation dose in Mamuju was found to be in a range from 17 to 115 mSv, averaging at 32 mSv. This
significantly surpasses the global average annual radiation dose of about 2.4 mSv. Lifetime exposure estimates
suggest that Mamuju residents could receive an average dose as high as 2.2 Sv. This is notably higher than the
average dose received by atomic bomb survivors, where risks of cancer and other diseases have been
established [2]. These results underline the need for thorough radiation exposure assessments in unique high
natural background radiation areas (HNBRA) like Mamuju [2-3].
Personal dosimetry is a crucial tool in radiation detection, primarily used to monitor individuals’ total
accumulation of ionizing radiation exposure. It is predominantly employed in the nuclear industry to ensure
worker safety. The device, which comes in various forms, such as stickers, badges, pens, or digital readout
devices, not only detects the exposure dose but also pinpoints the exact location of the radiation source. When
an individual is exposed to radiation levels exceeding the natural limit, the device promptly signals an alert [1].
Standard techniques used for radiation detection include film dosimeters, thermoluminescent dosimeters (TLD),
and, more recently, optically stimulated luminescence and radiophotoluminescence dosimetry. In this context,
personal dosimetry can be used to assess the occupational effect on workers’ health. In regions with high levels
of natural radiation, such as Mamuju Regency, West Sulawesi, Indonesia, personal dosimetry can also be used
to monitor the radiation exposure received by local residents. Mamuju Regency is known for its massive
radioactive mineral deposits, making it the area with the highest natural radiation in Indonesia [1-2]. Since most
of the population works as farmers, personal dosimetry measures the external dose to which residents are
naturally exposed [1-2].
This study was conducted in Mamuju Regency, where the primary focus was the occupational dose. This was
measured using a SmartRad personal dosimeter worn by a researcher. The study spanned 75 measurement
points across 5 sub-districts, providing valuable data for future radiation protection studies and enhancing our
understanding of the health effects of chronic low-dose-rate radiation exposure.

Research Method
Over the course of a month-long study, we utilized the SmartRad, a personal dosimeter device developed by
Enviro Korea Co., Ltd. This device is specifically engineered to monitor radiation exposure by detecting X-rays,
gamma rays, and beta rays. It was consistently worn on the chest of a researcher to monitor the occupational
dose during the time of the survey. The data was collected using a systematic random technique, as depicted in
Figure 1(a) [3].
The SmartRad operates within a measurement range of 0.1 μSv/hr to 10 mSv/hr for dose rate and 1μSv to 10 Sv
for cumulative dose. It has an energy range of 60 keV to 1.5 MeV. One of the critical features of the SmartRad is
its ability to inform the user of both direct measurement and cumulative external dose. This makes it a valuable
tool for anyone close to ionizing radiation sources. This includes but is not limited to workers in institutions using
isotopes, individuals involved in import, export, and distribution-related tasks, those in agriculture and fisheryrelated roles, frequent business travelers, and anyone interested in measuring radiation.
In addition to the SmartRad, we employed a separate GPS device to measure coordinates. The collected data,
which included dose level and coordinates point, was manually recorded on a pre-prepared worksheet. This
comprehensive approach allowed us to gather a robust dataset for our study.
The data undergoes processing to generate a two-dimensional map illustrating the spread of radiation dose
rates within the research zone. This map creation is achieved using Quantum Geographical Information System
(QGIS) software [5] to add and link all measurement points of the occupational exposure using the points-topath option. Additional analysis involves determining the effective dose individuals receive.

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(a)

(b)

Figure 1 (a) Track of the personal dosimetry measurements, (b) position of the personal dosimeter
device hanging on the chest of a team member.
The effective dose measures the average absorbed dose from a uniform whole-body radiation exposure that
yields the same total radiation detriment as the nonuniform, partial-body exposure being evaluated. This
concept, originally proposed by Jacobi in 1975 and further elaborated in McCollough and Schueler, is calculated
using a specific equation provided by the International Commission on Radiological Protection (ICRP) in their
latest publication in 2021 [6]:
𝐻𝑇 = ∑ 𝑊𝑅 ∙ 𝐷𝑇,𝑅

(1)

where HT is the equivalent dose, WR is the radiation weighting coefficient, and DT,R is the average dose absorbed
to tissue.

Result and Discussion
In this study, we collected 75 data points of external radiation dose rates, measured in microsieverts per hour
(μSv/hr). These measurements were taken over a period of minutes. We computed the average, standard
deviation, and median values from the external radiation dose rate data.
Table 1 Dose rate value in the research area.
N
Average
Standard Deviation
Max
Median
Min

Dose Rate (μSv/h)
75
0.94
0.79
4.20
0.64
0.15

Based on the measurements, the average dose rate recorded was 0.94 μSv/h, which equates to an estimated
annual dose of 8.24 mSv. This finding indicates a relatively high radiation exposure level in Indonesia’s Mamuju
region. Therefore, the current measurement aligns with previous findings, reinforcing Mamuju’s status as a

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Rakotovao Lovanantenaina Omega et al.

region with high natural radiation. This underlines the importance of ongoing monitoring and research to
understand the potential health implications for the local population.
The histogram presented in Figure 2 analyzes the dose rate distribution based on the collected data. Most of the
distribution, specifically from 42 data points, falls within the range of 0.152 to 0.822 μSv/h. This indicates that
the most frequently observed dose rates are within this range. However, there is an outlier in the data, with one
data point showing a significantly higher dose rate value, ranging between 4.172 and 4.842 μSv/h. This suggests
a substantial increase in the dose rate for this particular data point compared to the rest.

Figure 2 Dose rate measurement distribution.
Figure 3 displays a box-and-whisker plot, a type of quartile diagram illustrating the distribution of the measured
dose rate values. The distribution is positively skewed, indicating that most data points are concentrated
towards the lower end of the scale, with fewer data points extending towards the higher end.
The presence of outliers, specifically in the upper whisker (the section between the third quartile and the
maximum value), is noteworthy. These outliers represent unusually high radiation dose rates. The high radiation
dose rates may be attributed to substantial radioactive element mineralization or regions with radioactive
mineral deposits.

Figure 3 A quartile diagram showing the distribution of dose rate data that is positively skewed.

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Table 2 records radiation dose measurements taken at various locations in Mamuju, Indonesia. The
measurements include the cumulative dose, external exposure in millisieverts (mSv), time of measurement in
minutes, and the projected annual radiation dose in mSv. The effective dose, measured in millisieverts, is
particularly noteworthy as it represents the radiation risk to the entire body. This is especially relevant
considering that the average person in the U.S. is exposed to about 3 mSv per year from natural radiation [9,10].
The data revealed a wide range of radiation levels across different locations. For instance, the location with the
highest recorded cumulative dose and the projected annual dose was Ahu, while the location with the lowest
recorded values was Dayanginna-Tampalang. This variation underscores the importance of accurate and
consistent radiation dose measurements [11]. These findings are crucial for understanding the health effects
related to chronic low-dose-rate radiation exposure. They can also be used as the main input in future
epidemiological studies.
The accuracy of these measurements is paramount, as errors can lead to severe consequences such as failure of
tumor control or unacceptable normal tissue damage. To ensure accuracy, the study adhered to the guidelines
provided by various organizations such as the European Society of Radiology and the International Atomic
Energy Agency (IAEA). These organizations provide recommendations, calibration services, and internationally
harmonized dosimetry codes of practice [12,13].
Furthermore, the study consulted other research efforts in the field. For example, a study published in the British
Medical Journal that calculated descriptive statistics for CT scans by patient, institution, practice volume,
machine, and country. The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) also conducts
tests for ongoing equipment validation [14,15].
These studies highlight the importance of accurate radiation dose measurements and the efforts made by
various countries and international organizations to ensure consistency and quality assurance in this field.
Table 2 Cumulative and effective dose measured in mSv per year.
Location
Dayanginna-Tampalang
Dayanginna-Malunda
Pantai Taan-Karanamu
Mamuju - Tasiu
Labuanrano
Bullung
Kamarang, Taan
Rantedoda
Desa Taan, Kec. Tapalang
Palada, Takandeang
Hulu Ampalas
Taloba, Takandeang
Ahu

μSv

mSv

1.00
0.50
0.10
2.20
0.40
0.70
0.60
4.40
5.00
2.70
5.30
1.82
8.40

0.001
0.001
0.000
0.002
0.000
0.001
0.001
0.004
0.005
0.003
0.005
0.002
0.008

Cumulative Dose
Time of measurement
(Minutes)
304
135
25
363
62
86
71
311
352
178
250
61
189

mSv in 1 year
1.73
1.95
2.10
3.19
3.39
4.28
4.44
7.44
7.47
7.97
11.14
15.68
23.36

External exposure
(mSv)
1.52
1.71
1.85
2.80
2.98
3.76
3.91
6.54
6.57
7.06
9.81
13.80
20.57

The bar graph presents a comparison of the cumulative dose per year (in milliSieverts, or mSv) across various
locations, such as Dongguan, Donghai, Fuzhou, Manjur, Kamming, Hulu, Fuzhou, Anhui, and others. The y-axis,
ranging from 0 to 25 mSv, represents the cumulative dose per year. Two data sets or categories are depicted for
each location, represented by red and blue bars. Generally, the red bars are taller than the blue ones, indicating
higher values for the data they represent. The graph provides a clear visual representation of the variation in
cumulative dose per year across different locations. A consistently taller red bar is seen in Ahu, typically higher
across all locations than those represented by the blue bars. Regardless of location, the red bars, which represent
one set of data, consistently show higher values than the blue bars. This finding suggests a significant difference
between the two data sets across all examined locations.

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Cumulative doe per year (mSv)

25

20

15

10

5

0

Figure 4 Distribution of cumulative dose values received by individuals in one year.
The high radiation dose rate and cumulative dose recorded in this study using a personal dosimeter can be
attributed to uranium and thorium mineralization, two common natural radioactive elements with high
concentrations in the Earth’s crust. Their natural radioactivity plays a significant role in environmental sciences
for monitoring radiation dose and geological sciences for understanding sedimentary processes. For instance,
the Odisha coastal area in eastern India is a well-known high background radiation area rich in monazites and
rutile. The concentrations of uranium and thorium were measured using inductively coupled plasma mass
spectrometry (ICP-MS). The ratios of Th/U and Th/K varied from 4 to 37 and 13 to 1058, respectively. These
results clearly indicate that the samples from the coastal region were formed in an oxidizing and intense
chemical weathering terrestrial environment with enrichment of radiogenic heavy minerals (monazites and
zircon) and clay mineral association. Since most samples have undergone moderate to intense weathering in the
oxidizing environment, uranium is leached from the soil and sand matrix. Eventually, thorium resides in the
matrix and is a major source of radiation exposure in the environment [17-19].
Ahu
Taloba, Takandeang
Bebanga
Hulu Ampalas
Palada, Takandeang
Desa Taan, Kec. Tapalang
Rantedoda
Kamarang, Taan
Bullung
Labuanrano
Mamuju - Tasiu
Pantai Taan-Karanamu
Dayanginna-Malunda
Dayanginna-Tampalang

20,5568
13,8000
12,8480
9,8056
7,0159
6,5700
6,5438
3,9087
3,7648
2,9841
2,8032
1,8501
1,7131
1,5215
0

5

10

15

20

Effective dose in 1 year (mSv)

Figure 5 Distribution of effective dose in the study area.

25

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The elevated cumulative dose values observed in the study regions are further evidenced by the distribution of
effective dose values, as illustrated in Figure 6 and Table 2. The maximum effective dose value is found in areas
identified as radioactive mineral deposit areas, represented by the red bars in the graph. The highest value was
recorded in Taloba, within the village of Takandeang.

Summary
This study in Indonesia’s Mamuju region aimed to measure external exposure using a personal dosimeter. It was
found that this area has a relatively high radiation exposure level. The average external dose rate was 0.94 μSv/h,
which is equal to an estimated annual dose of 8.24 mSv. This aligns with previous findings that characterized
Mamuju as a high natural background radiation area (HNBRA), with residents potentially receiving an average
cumulative dose as high as 2.2 Sv. The location with the highest recorded cumulative dose and annual external
dose was Ahu. The high radiation dose rate and cumulative dose recorded in this study can be attributed to
uranium and thorium mineralization. Their natural radioactivity plays a significant role in environmental sciences
for monitoring radiation dose and geological sciences for understanding sedimentary processes. These findings
are crucial for understanding the health effects of chronic low-dose-rate radiation exposure and can be used as
the main input in future epidemiological studies.

Acknowledgements
This research was supported by the Ministry of Education and Culture of the Republic of Indonesia and an
innovative research grant of Institut Teknologi Bandung.

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Manuscript Received: 29 June 2023
1st Revision Manuscript Received: 14 November 2023
2nd Revision Manuscript Received: 27 December 2023
Accepted Manuscript: 30 December 2023