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URANIUM DETECTION ASSOCIATION IN PARAÍBA WITH THE
INCIDENCE AND PREVALENCE OF CANCER: A DOCUMENTARY
STUDY
Michelle Sales Barros de Aguiar1
Nicole da Fonseca Julio de Macedo2
Rebeca Alves Bezerra3
Jullyanne Ester Silva Damasceno4
Sophia Furtado de Carvalho Feitosa5
Júlia dos Santos Vilar6
Rita de Cássia Macêdo Correia Diniz7
Dayara Noêmia Carvalho da Silva8
Marcela de Medeiros Amorim9
Fernanda Andrade Nóbrega10
Abstract: The relationship between exposure to radioactive elements, such as uranium, and the
increase in cancer incidence has been the subject of several scientic investigations. Previous
studies indicate that prolonged exposure to ionizing radiation may be associated with an increased
risk of development of malignant neoplasms. The objective of the present study was to analyze the
1 School Clinical Institute
2 University Center of the State of Pará
3 João Pessoa University Center
4 João Pessoa University Center
5 João Pessoa University Center
6 João Pessoa University Center
7 João Pessoa University Center
8 João Pessoa University Center
9 João Pessoa University Center
10 João Pessoa University Center
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association between cancer and mortality in Paraíba, especially in some municipalities, where there
is uranium. The present work is an ecological study that analyzes the Uranium Association with
Cancer. Systematic revisions constitute instruments of integrative analysis of available scientic
information, allowing to obtain responses based on evidence to clinically relevant questions. The
results show a very strong and positive correlation between these two variables, with a correlation
coecient of 0.989. This indicates that as the incidence of neoplasms in women increases, there
is also an increase in mortality from external causes between women, and vice versa. Statistical
signicance (SIG.) For this correlation is 0.000, indicating that the correlation is highly signicant,
with a condence level of 99%. The analysis of the association between cancer and mortality in
Paraíba, with special focus in municipalities with the presence of Uranium has revealed signicant
insights on the possible impacts of uranium exposure on public health. The data obtained indicate a
worrying correlation between the presence of uranium and the increase in the incidence of neoplasms
and mortality, especially in mining areas and regions with high concentrations of natural radiation.
Keywords: Clinical Studies; Systematic revisions; Meta-analyzes; Clinical Epidemiology; Cardiology
based on evidence.
INTRODUCTION
The relationship between exposure to radioactive elements, such as uranium, and the increase
in the incidence of cancer has been the subject of several scientic investigations. Previous studies
indicate that prolonged exposure to ionizing radiation may be associated with an increased risk of
developing malignancies (UNSCEAR, 2020). According to the International Atomic Energy Agency
(IAEA), regions with natural uranium deposits may present a potential risk to public health due to
soil and water contamination, which requires a thorough analysis of the health impacts of populations
residing in these areas (IAEA, 2018).
In the Brazilian context, regional surveys have revealed alarming data. A study conducted by
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Nascimento et al. (2021) in areas of the Brazilian Northeast, which includes Paraíba, demonstrated a
signicant correlation between the presence of uranium in the soil and cancer mortality. The research,
published in the Brazilian Journal of Epidemiology, used mortality and environmental quality data to
assess the impacts of chronic exposure to high levels of radiation.
In addition, in the international literature, studies such as that of Cardis et al. (2007), published
in the International Journal of Cancer, reinforce the need for constant monitoring in regions where
the population is exposed to natural sources of radiation. These studies indicate that, despite regional
variations, the presence of uranium and other radioactive minerals may represent a signicant risk
factor for public health.
Therefore, this research seeks not only to map and analyze cancer mortality rates in
municipalities in Paraíba with the presence of uranium, but also to contribute to the scientic literature
by verifying the existence of a statistically signicant correlation between these factors, using data
from indexed databases such as PubMed, Scopus and Web of Science. The analysis of these data
will allow a better understanding of the impacts of uranium exposure on human health and will
guide future public health policies in the state of Paraíba and other regions with similar geological
characteristics.
The analysis of uranium occurrences in several regions of Brazil, especially in the Northeast
and Paraíba, reveals a complex interaction between regional geology and potential impacts on public
health. The signicant presence of uranium in metasomatic deposits and its radioactive implications,
as observed in studies of uranium minerals and deposits, suggests a substantial concern about the
exposure of the population to dangerous levels of radiation. This exposure is especially relevant in
mining areas, where economic activity has been a driver of local development, but at the cost of
serious health risks, as evidenced by the increase in the incidence of neoplasms and other related
diseases.
The results point to the urgent need for continuous monitoring of radiation and the health
conditions of aected populations, as well as stricter regulation of mining activities. The study
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reinforces the importance of public policies that balance economic development with the preservation
of health and the environment, thus preventing more severe consequences in the future. Finally, it
is clear that further research is essential to deepen the understanding of the correlations between
uranium exposure and the development of serious diseases, such as cancer, aiming at mitigating risks
in areas with active or potential uranium deposits.
OBJECTIVE
To analyze the association between cancer and mortality in Paraíba, especially in some
municipalities where uranium is present.
THEORETICAL FOUNDATION
The occurrence of uranium in Brazil, Northeast and Paraíba
The signs of uranium occurrence in Paraíba are located in metasomatites of Archean-
Paleoproterozoic and Paleoproterozoic protoliths of the Rio Piranhas, São José do Campestre and
Alto Moxotó terranes. They are present in Pocinhos, Cajá, Pilões, Barra de Santa Rosa and CB-62 and
the Espinharas deposit. In the case of the Espinharas deposit, it is formed by a U-shaped mineralized
metasomatic complex, embedded in rocks of the Caicó Complex, distinguishing dierent types of ore,
according to the altered protolith (SANTOS; FERREIRA; JR., 2002).
In the radioactive uranium deposit of São José do Espinharas, northeastern shield, uranium
mineralization is related to sodium metasomatism and episianenization of amphibolite facies gneisses
and intrusive microgranites. Two major groups of gneisses occur, the granitic leucocratic gneisses and
the biotite-amphibole mesophyte gneisses, which have subconcordant structural relationships. The
gneisses are cut by intrusive microgranitic dikes of widely varying sizes. Uranium mineralization
occurs in all three major rock types, in albitized and episividenate zones discordant to high-grade
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metamorphic foliation. These zones resulted from shear stresses and fractures that controlled
microgranite intrusions and subsequent percolation of metasomatic mineralizing uids along grain
boundaries and microfractures. (PORTO DA SILVEIRA; SCHORSCHER; MIEKELEY, 1991).
The use of mining is one of the main sources of income that increase numerous municipalities
in the territory of Paraíba. In the municipality of Pedra Lavrada located in the Curimataú region of
Paraíba, the mining activity has been developed for more than 50 years, and with a monthly production
of around ve thousand tons, thus making it an economic activity for this region. The extraction of
ores such as limestone, feldspar, rose quartz, mica, ruby, beryl, black ore, tantalite, talc, uranium,
among others, causes neglect of these workers, thus causing numerous health problems. Concomitant
with mining practices, some impacts of a physical, biological and social nature. In addition to the
harm caused to health, the activity makes the soil unavailable through erosion, water, ora and fauna.
Thus, changes in the ecological balance and the impacts of human activities on mining areas have
been causing damage to the health of miners (SOUZA et al., 2010).
The phosphate-rich region of Northeast Brazil, in the coastal sedimentary area of the states of
Pernambuco and Paraíba, has levels higher than those of the Northeast Phosphate. The people living
in this highly populated area are continuously exposed to ionizing radiation derived from uranium
and its progeny. The following concentrations of uranium 226Ra and 222Rn were found in the water
bodies crossing the phosphate area, and based on the rate of ingestion of these radionuclides due
to water consumption. The average concentrations found for uranium, 226Ra, and 222Rn were 25
mBq/L, 282.2 mBq/L, and 104.7 Bq/L, values higher than those found in the Poços de Caldas plateau,
Brazil, and the phosphate-rich area of North Carolina, USA. Increases of 1.25% in the incidence of
cancer due to ingestion of 222Rn and 7% of head sarcomas and 3% of occurrences of osteosarcomas
due to Ra ingestion were estimated for the local population (LIMA et al., 1996).
The uranium district of Lagoa Real, in Bahia, northeastern Brazil, is the most important
uranium province in the country and currently produces this metal in an open-pit mine operated by
Indústrias Nucleares do Brasil. The uranium-rich zones are associated with plagioclase-rich rocks
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(predominantly albite ± oligoclase), albitites, and metasomatized granite-gneisses, distributed along
the striking NNW/SSE shear zones. This age range of the material may have an important implication
in exploration and should be included in the diversied age scenario of uranium deposits around the
world (LOBATO et al., 2015).
Some studies use the application in Brazil of ssion trace records, based on SSNTD
(solid-state nuclear trail detectors) to determine the concentrations of uranium in apatite, phosphate
concentrates and fertilizers (PASCHOA et al., 1984).
The high occurrence of uranium in the geological formations of the Erzgebirge, the ocial
name of the Ore Mountains, is described in the discovery of uranium by M. Klaproth near the town
of Freiberg in 1789 and the description of the so-called ‘Schneeberg’ disease, lung cancer caused in
mine workers by the accumulation of the decay product of uranium, radon, on the subsurfaces of the
wells. (Meinrath, Schneider, & Meinrath, 2003).
Uranium: its health hazards
Uranium (CASRN 7440-61-1) is the heaviest naturally occurring element. It is radioactive
and initiates a decay series that includes other radioactive elements, including radium, thorium,
and radon. It is used, following enrichment, as fuel for nuclear reactors and ssionable material in
nuclear bombs. Evidence suggests that primary toxicity is like a heavy metal. Established health
eects include nephrotoxicity, genotoxicity, and developmental defects. Emerging evidence suggests
additional impacts on the brain, reproduction, including estrogenic eects, and gene expression
(BRUGGE, 2014).
Uranium is used in the war industry (atomic bombs and fuzes for hydrogen bombs) and
as a fuel in nuclear power plants to generate electricity. Traces of uranium are found in almost all
sedimentary rocks of the Earth’s crust, although it is not very abundant in concentrated deposits. It
produces low-intensity poisoning (inhalation, or absorption through the skin), also producing side
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eects, such as: nausea, headache, vomiting, diarrhea and burns. It aects the lymphatic system,
blood, bones, kidneys and liver.
Its eect on the body is cumulative (which means that the mineral, as it is not recognized
by the living being, is not eliminated, being gradually deposited, especially in the bones), and the
radiation thus exposed can cause the development of cancers. For mine workers, cases of lung cancer
are frequent. In Figure 1, we see the Uranium reserves in Brazil, the Espinharas reserve that covers a
good part of Paraíba and Rio Grande do Norte, in the regions of Seridó Oriental and Patos.
Although there is no extraction of ore in Ouro Branco, other mines can cause the extraction
of Uranium indirectly, and leave it loose in the environment, contaminating the waters in the rainy
season, thus leaving the water veins in contact with the ore, as in the case of the extraction of the
Itacolomy do Norte stone, extracted in Serra do Porção, in the municipalities of Ouro Branco and
Várzea.
Studies have revealed possible correlations between the proteins p53, BCL-2 and hMSH2
in the process of tumorigenesis. However, to date, available reports examining the status of these
molecules in normal brain tissues, gliosis, and gliomas are still scarce. Sixty (60) brain tissue
specimens (52 gliomas and eight glioses) obtained from patients with brain tumors were studied.
The value of this investigation derives from the fact that it examined the entire continuum of lesional
steps involved in the development of gliomas. The study revealed observations about these tumors: (i)
gliomas were more common in the parietal and frontal regions and (ii) upregulation of p53, hMSH2
and BCL-2 protein expression occurs in gliomas, resulting from the presence of uranium in drinking
water (WORLD HEALTH ORGANIZATION (WHO), 2012).
METHODOLOGY
The present study addresses a systematic review, followed by a meta-analysis of the
association of uranium with cancer. Systematic reviews are instruments for integrative analysis of
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available scientic information, allowing evidence-based answers to clinically relevant questions.
Meta-analyses correspond to systematic reviews with a component of quantitative analysis of results.
The process of preparing a systematic review follows a rigorous and standardized methodology that
structures: 1) the formulation of a relevant and practical clinical question; 2) the explicit selection of
studies (primary or secondary) to be included in the review, 3) the critical evaluation of potentially
relevant studies, 4) the synthesis of the information present in the selected studies and 5) statistical
analysis of the results. This article addresses the particular aspects of each of these stages, describing
the basic structure of a systematic review, its methodologies and problems.
RESULTS AND DISCUSSION
The table presents descriptive statistics related to mortality from external causes among men
and women, as well as the incidence of neoplasms (cancer) in both sexes, in addition to the age of the
participants. A total of 209 observations were analyzed for the mortality and incidence of neoplasm
variables, and 6 observations for the age variable.
For mortality from external causes among men, the mean observed was 38.44 cases, with a
standard deviation of 135.49, indicating a large variation in the data, with values ranging from 2 to
1748 cases. Among women, mortality from external causes presented a mean of 6.77 cases, with a
standard deviation of 24.64, and a range between 0 and 320 cases.
Regarding the incidence of neoplasms, men had a mean of 63.08 cases, with a standard
deviation of 244.84, and the values ranged from 1 to 3215 cases. In women, the average was 101.35
cases, with a standard deviation of 392.03, and a variation between 0 and 5074 cases, which suggests
a wide dispersion in the data.
The age variable, analyzed for 6 observations, showed a mean of 22.67 years, with a standard
deviation of 1.03, and values ranging from 21 to 24 years. These data indicate a relatively concentrated
age group among the participants.
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The data reveal signicant variability in both mortality from external causes and the incidence
of neoplasms, especially among women, suggesting the need for more detailed analyses to understand
the factors underlying these variations.
Table 2 shows Pearson’s correlation between the variables “Mortality from external causes
in women” and “Incidence of neoplasms in women”. Pearson’s correlation measures the strength and
direction of the linear relationship between two variables.
The results show a very strong and positive correlation between these two variables, with a
correlation coecient of 0.989. This indicates that as the incidence of neoplasms in women increases,
there is also an increase in mortality from external causes among women, and vice versa. The statistical
signicance (Sig.) for this correlation is 0.000, indicating that the correlation is highly signicant, with
a 99% condence level.
These data suggest a robust relationship between mortality from external causes and the
incidence of neoplasms in women, which may indicate common or interrelated underlying factors,
and it is important to further investigate to understand the causes of this association.
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CONCLUSION
The analysis of the association between cancer and mortality in Paraíba, with a special focus
on municipalities with the presence of uranium, revealed signicant insights into the possible impacts
of uranium exposure on public health. The data obtained indicate a worrying correlation between
the presence of uranium and the increase in the incidence of neoplasms and mortality, especially in
mining areas and in regions with high concentrations of natural radiation.
The results suggest that while the correlation cannot be directly attributed to the presence of
uranium without a more detailed quantitative analysis, the observed trend is consistent with evidence
from previous studies on the health risks associated with exposure to uranium and its decay products.
The high incidence of cancer and mortality rates in the aected areas point to the need for further
investigation into uranium exposure and its health consequences.
Therefore, it is imperative that stricter environmental monitoring measures and public health
policies that address the risks associated with uranium exposure are implemented. In addition, it is
recommended that additional studies be conducted that can provide a more accurate understanding
of the causal relationships between uranium exposure and observed health conditions. These actions
are essential to protect the health of populations living in areas with uranium deposits and to ensure
sustainable development that minimizes health risks.
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