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European Journal of Applied Sciences – Vol. 10, No. 1
Publication Date: February 25, 2022
DOI:10.14738/aivp.101.11419. Brigui, O. J., Agbo, D. D. A., & Monnehan, G. A. (2022). Assessment of Natural Radioactivity in Gravel Samples Collected from Abidjan
District in Côte d’Ivoire. European Journal of Applied Sciences, 10(1). 126-134.
Services for Science and Education – United Kingdom
Assessment of Natural Radioactivity in Gravel Samples Collected
from Abidjan District in Côte d’Ivoire
BRIGUI Olkalé Jean-Claude
Laboratoire des Sciences de la Matière, de l’Environnement et de
l’Energie Solaire, UFR des Sciences des Structures de la Matière et
Technologie, Equipe de physique Nucléaire et Radioprotection
Université Félix Houphouët Boigny, Abidjan, Côte d’Ivoire
AGBO Djama Djoman Alfred
Laboratoire des Sciences de la Matière, de l’Environnement et de
l’Energie Solaire, UFR des Sciences des Structures de la Matière et
Technologie, Equipe de physique Nucléaire et Radioprotection
Université Félix Houphouët Boigny, Abidjan, Côte d’Ivoire
MONNEHAN Georges Alain
Laboratoire des Sciences de la Matière, de l’Environnement et de
l’Energie Solaire, UFR des Sciences des Structures de la Matière et
Technologie, Equipe de physique Nucléaire et Radioprotection
Université Félix Houphouët Boigny, Abidjan, Côte d’Ivoire
Autorité de Radioprotection, de Sûreté et Sécurité Nucléaires
Abidjan, Côte d’Ivoire
ABSTRACT
Gravel is one of the reference materials used in the construction sector and in
particular in Côte d'Ivoire. In this study, which appears to be one of the first works
on construction materials in Côte d'Ivoire, radiological measurements are carried
out on ten (10) samples of gravel from the district of Abidjan in order to evaluate
the activity concentration of natural radionuclides (226Ra, 232Th and 40K). The
measurements are made using the nuclear technique based on gamma
spectrometry with a GeHP detector. The average activity concentrations in the
samples were 5.98± 0.24 Bq.kg-1, 4.17± 1.65 Bq.kg-1 and 177.18± 3.50 Bq.kg-1 for
226Ra, 232Th and 40K respectively. These values, which were the first results
obtained, show that the natural radioactivity in these gravels is comparable to what
is usually measured in the same samples on a world scale, whose average limit
values are 35 Bq.kg-1, 30 Bq.kg-1 and 400 Bq. kg-1 (UNSCEAR, 2000). Therefore, the
radioactivity in these gravels does not pose an immediate health risk to the public.
Long-term effects can be avoided by simple precautionary measures.
Keywords : Gamma spectrometry Technique, gravel samples, District of Abidjan, activity
concentration
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Brigui, O. J., Agbo, D. D. A., & Monnehan, G. A. (2022). Assessment of Natural Radioactivity in Gravel Samples Collected from Abidjan District in
Côte d’Ivoire. European Journal of Applied Sciences, 10(1). 126-134.
URL: http://dx.doi.org/10.14738/aivp.101.11558
INTRODUCTION
Populations are subjected to environmental ionizing radiation from a wide variety of sources.
A part from the direct irradiation due to cosmic rays, human been is subjected to an irradiation
due to radioelements of natural origin contained in the ground, the rocks or the building
materials. Most of this radioactivity is due to elements of the uranium-238, thorium-232 and
potassium-40 series [1]. These radionuclides can cause adverse effects on human health,
particularly through external exposure to gamma radiation, ingestion or inhalation due to their
ionizing radiation on the body [2].
According to [3], the term “gravel” typically refers to pieces of crushed stone often basalt,
sandstone, or lime stone that are categorized by size, composition, color, or shape. Today; pea
gravel, river rock, and stone dust can all be considered gravel. There are many of applications
for these stone products in construction. The authors in [3] reported that from acting as fill
material or pipe bedding to making up foundations and roads, gravel is a versatile material that
comes in many shapes and sizes. Gravel is one of the reference materials in the construction
sector in Côte d'Ivoire. It is an important part in the different construction works. The risks
associated with construction materials can become important in the case of high levels of
radionuclides or chronic exposure over many years. This study is a preliminary assessment and
aims to assess the levels of naturally occurring radioactivity in samples of gravel used in the
Abidjan District in the various construction sectors.
MATERIALS AND METHODS
Study area
The District of Abidjan is located between latitudes 5°10 and 5°38 North and longitudes 3°45
and 4°21 West. Covering an area of 2119 km2, the District of Abidjan has a population density
of 2221 inhabitants / km2. Its population is estimated at 4,707,404 with a growth rate of 3.7%
[4]. Geologically, it belongs to the coastal sedimentary basin (figure 1).
Materials
Sampling and preparation equipment
The materials analyzed during this work are ten (10) samples of gravel. The equipment used in
the field for sample collection includes a Garmin (etrex) brand GPS to determine geographic
coordinates, shovels for manual collection and polythene sample bags. The laboratory
equipment used for sample preparation consists of a METTLER TOLEDO brand electronic
balance (Model: XP2001S, SNR; B044082756,12V / 2.25A) for different mass measurements of
the samples. There are also Marinelli beakers (SG 500) for the conditioning of the samples, an
oven for drying the samples, a ball mill and a sieve of 2 millimeters mesh.
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European Journal of Applied Sciences (EJAS) Vol. 10, Issue 1, February-2022
Services for Science and Education – United Kingdom
Figure 1: Map of the study area (District of Abidjan)
Equipment analysis
The radioactivity of the sand samples is measured using the gamma ray spectrometer installed
at the laboratory of the Radiation Protection Institute (RPI) of GAEC (Ghana). The measurement
chain includes the measurement chamber, a liquid nitrogen cooling system (77 K), a High purity
Germanium (HPGe) coaxial detector model GX 4020-7500 SL (Canberra brand ) and with a
resolution of 2 keV at 1332 keV (60Co).There are also a high voltage power supply (4000V)
essential for the collection of the quantity of electric charges deposited in the detector, a
cylindrical lead shielding 10 cm thick making it possible to reduce contributions of ambient
Scale
Study area
Hydrographi
c network
Atlantic ocean