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Introduction
Considerable attention has been given worldwide to the study
of high background radiation areas (HBRAs).
1–3
Some of these are
found in China, India, Iran, United States, Canada, and Brazil.
3
A
HBRA is defined as “an area or a complex of dwellings where the
sum of exposures from cosmic radiation and natural radioactivity of
soil, indoor and outdoor air, water and food intake result in an annual
effective dose to the public above the level of the global average of
2.4 mSv y
-1
” defined by the United National Scientific Committee on
the Effects of Atomic Radiation (UNSCEAR).
4
HBRAs have been
classified into four levels: low (<5 mSv y
-1
); medium (5–20 mSv y
-1
),
high (20–50 mSv y
-1
); and very high (>50 mSv y
-1
).
5
Some of these
areas have been under study for many years to determine the risks and
effects of chronic low dose long term exposure for natural radiation.
6
High backgrounds are normally due to high concentrations into the
lithosphere of radionuclides from the three natural series starting with
238
U,
232
Th and
235
U. Plants grown in such areas are thus susceptible
to bioconcentrate natural radioactivity. Human contribution to
environmental contamination principally came from the military
tests carried out during the 50ths and 60ths of last century or resulted
from waste piles and effluents of uranium mining, nuclear wastes
from nuclear power plants or nuclear accidents (e.g. Chernobyl,
Fukushima,…) contributing to increase, locally or in large scale,
backgrounds around the world.
Naturally occurring radionuclides are found in a variety of
concentrations in every compartment of the earth: soil, water and
atmosphere, and also in the tissue of all living beings (biosphere)
subjecting human beings to a daily exposure.
Anthropic contamination is found more topically in areas affected
by nuclear power plants explosions, nuclear bombs testing and more
recently from the use of depleted uranium weapons. Such events
affected mainly nearby soils, but also hydrographic basins and the
atmosphere, mainly of the Northern hemisphere.
Consequently, people are exposed to ionizing radiation from
naturally occurring and anthropic radionuclides that may be present
in their food in unpredictable concentrations. Thus, besides anthropic
137
Cs i.a., natural radionuclides belonging to the
232
Th and
238
U series
as well as
40
K are the main contributors to radiation in foods.
5
As these
radionuclides are not uniformly distributed in soils, the knowledge
and measurement of their concentrations in foods play an important
role in human radiation protection.
According to the International Food Safety Authorities Network
(INFOSAN),
7
plants used as food commonly possess trace amounts
of
40
K,
232
Th and
238
U and their progenies. And this is also the case of
sugar cane, from which most of the sugar consumed over the world
is produced.
Gamma-ray spectrometry using high-purity germanium detectors
(HPGe) is a procedure widely used for determining the concentrations
of natural and artificial radionuclides in environmental samples. As
a nondestructive technique, this method possesses advantages in
simultaneous multi-element analysis, simplified sample preparation
(no chemical separation processes are required), and applicability
for precise quantitative determination of the radioactive content in
a sample. The most accurate and reliable method to determine the
activity concentration of radionuclides is to use an adequate standard
source with similar geometrical dimensions, density, and chemical
compositions to the sample under study.
8
This study aims to determine activities concentrations (AC) of
the radionuclides
226
Ra,
212
Pb,
214
Bi and
40
K in sugar samples obtained
from producers from 4 Brazilian cities located in the Southeast and
Midwest regions: Pirajuba (State of Minas Gerais), Edeia (Goiás),
Pitangueira (São Paulo) and Mendonça (São Paulo). The absorbed
and effective doses due to sugar ingestion were also estimated.
MOJ Public Health. 2023;12(3):132‒135. 132
©2023 Alcantara et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which
permits unrestricted use, distribution, and build upon your work non-commercially.
Evaluation of radionuclides in sugar samples from
different regions of Brazil
Volume 12 Issue 3 - 2023
Clarisse F Alcantara,
1
Ian A Kastrup,
1
Alphonse Kelecom,
2
Rayline L Silva,
2
Lorena
VS Santos,
2
Leandro S Barbosa,
3
Carlos O
Pastrana,
3
Marco A Frota
1
1
Central Radiometric Laboratory, Department of General
Biology, Fluminense Federal University, Niterói, Brazil
2
Laboratory of Radiobiology and Radiometry LARARA-PLS,
Department of General Biology, Fluminense Federal University,
Niterói, Brazil
3
Nuclear Engineering Program, Federal University of Rio de
Janeiro, Rio de Janeiro, Brazil
Correspondence: Marco A Frota, Central Radiometric
Laboratory, Outeiro de São João Batista, s/n, or
Postal Box: 100.436. 24001-970 Niterói RJ, Brazil,
Email
Received: September 28, 2023 | Published: October 12, 2023
Abstract
Sugar contains radionuclides and its consumption may result in an increase of the internal
dose in humans. Thus, this work evaluates the profile and activity of radionuclides present
in 4 VHP sugar samples obtained from producers from 4 cities in Brazil, located in the
Southeast and Midwest regions: Pirajuba (State of Minas Gerais), Edeia (Goiás), Pitangueira
(São Paulo) and Mendonça (São Paulo). The samples were collected between the years
2019 and 2020. The analyzes were performed by gamma spectrometry using a hyper pure
germanium semiconductor detector (HPGe) counting the samples over a period of 24 hours.
The same profiles of radionuclides
226
Ra,
212
Pb,
214
Bi,
40
K were observed in all samples,
except for the sample from Mendonça, which presented a low counting rate for
214
Bi.
Calculations of specific activity were carried out for the two most abundant radionuclides,
226
Ra and
40
K, obtaining the following values (in Bq kg
-1
): for
226
Ra Pirajuba (22.43 Bq kg
-1
),
Edeia (22.38 Bq kg
-1
), Pitangueira (18.25 Bq kg
-1
) and Mendonça (36.16 Bq kg
-1
) and for
40
K Pirajuba (0.66 Bq kg
-1
), Edeia (0.99 Bq kg
-1
), Pitangueira (0.66 Bq kg
-1
) and Mendonça
(0.33 Bq kg
-1
). Additionally, the values of total absorbed dose rate were calculated: Pirajuba
(43.61 nGy h
-1
), Edeia (43.60 nGy h
-1
), Pitangueira (41.82 nGy h
-1
) and Mendonça (49.45
nGy h
-1
). Therefore, according to the United Nations Scientific Committee on the Effects of
Atomic Radiation, the results obtained did not show a significant transfer of absorbed dose
due to radionuclides from sugar consumption under the conditions adopted in this work.
No variation of radiation dose according to the region or year of production was observed.
Keywords: radionuclides, sugar, spectrometry, gamma spectroscopy
MedCrave Online Journal of Public Health
Research Article
Open Access