RESUMO
The radiometric monitoring carried out in the present study allowed the discovery of anomalous granite outcrops in natural radionuclides in the rural area of São Mamede in the state of Paraíba, Brazil. The characterisation study made it possible to determine maximum specific concentrations of approximately 199 kBq kg-1 of 238U, 85 kBq kg-1 of 226Ra, 26 kBq kg-1 of 232Th and 24 kBq kg-1 of 40K. Models for environmental dosimetry were applied, which resulted in obtaining the following quantities: radium equivalent (Raeq), indices of external (Hex), internal (Hin) and representative (Iyr) damage, and the effective outdoor dose (HE). The maximum results presented were approximately 123 kBq kg-1, 332, 562, 832, and 68 mSv y-1, respectively. Consequently, it was possible to define the region as of high radioactive background due to isolated rocky outcrops located in the rural area of the mentioned municipality.
Assuntos
Radiação de Fundo , Radioisótopos de Potássio/análise , Monitoramento de Radiação/métodos , Rádio (Elemento)/análise , Poluentes Radioativos do Solo/análise , Tório/análise , Urânio/análise , BrasilRESUMO
Environmental radioactivity studies have been allowed establishing radiometric patterns in several area of the earth's crust. The work was conducted through radiometric analyses of regions with high levels of radionuclides and others with no history of anomalies. The research allowed establishing the radiometric profile of soils in the state of Pernambuco, Brazil, using a gamma spectrometry system. The specific activities ranged from 16.5 to 287.5 Bq kg-1 for 238U, 2.0 to 191.7 Bq kg-1 for 226Ra, 1.3 to 281.4 Bq kg-1 for 232Th and from 5.0 to 2600.9 Bq kg-1 for 40K. The results showed areas with low levels of ionizing radiation. However, for 40K some points presented high values, although non-representative of the number of samples investigated. The 226Ra/238U and 232Th/238U ratios allowed to determine the radioactive imbalance condition and to obtain information about aspects of soil availability providing an assessment of the dynamics of these radionuclides.
Assuntos
Monitoramento Ambiental/métodos , Monitoramento de Radiação/métodos , Radioisótopos/análise , Poluentes Radioativos do Solo/análise , BrasilRESUMO
A marine phosphorus region with high concentrations of phosphate, coastwise of Pernambuco, Northeast of Brazil, is densely inhabited. Rock phosphate deposits naturally contain uranium ore that produces ionizing radiation from it and its natural descendants, furthermore, its thorium and potassium concentrations are comparable to those usually found in soils. Radiological monitoring of this environment is important to verify the occurrence of harmful effective doses for the adjacent population. This study aimed at the in situ radiometric monitoring in four cities of the north of the Metropolitan Region of Recife-Pernambuco, estimating the effective environmental dose to which the local population is subject. In total, 91 points were monitored with a discriminator-type detector. The outdoor environmental effective dose rates ranged from 1.99 ± 0.09 to 7.59 ± 0.36 mSv y-1, with an average of 2.60 ± 0.69 mSv y-1.
Assuntos
Poluentes Radioativos do Ar/análise , Radiação de Fundo , Fosfatos/análise , Monitoramento de Radiação , Radiação Ionizante , Poluentes Radioativos do Solo/análise , Urânio/análise , Humanos , Doses de RadiaçãoRESUMO
High levels of primordial radionuclides have been reported in soils and rocks of São José de Espinharas, in the state of Paraiba, Brazil. These radionuclides are derived from high concentrations of natural uranium and thorium from a mine in the region. Thus, there is a need for a dosimetric evaluation in the area near the mine and the surrounding cities. In this study, the annual effective dose was analyzed in 178 points of five cities. The measurements were performed using thermoluminescent dosimetry with LiF:Mg, Ti (TLD-100). The annual effective dose from environmental exposure varied from 0.71 to 2.07 mSv, with an arithmetic mean of 0.99 mSv. This average is more than twice the estimated value for indoor environments adopted by the UNSCEAR, which is 0.41 mSv. These results will allow establishing reference values for background radiation of the region and criteria to infer a stochastic risk for the local population.
Assuntos
Radiação de Fundo , Poluentes Radioativos do Solo/análise , Dosimetria Termoluminescente/métodos , Urânio/análise , Brasil , Humanos , Doses de Radiação , Tório/análiseRESUMO
An increase of health problems has been reported in the city of Triunfo, Paraíba, NE Brazil. This pattern has been attributed to environmental radiation since there are uranium deposits in the neighboring municipalities. The present study aimed to carry a radiometric survey in Triunfo to determine effective dose from external outdoor radiation exposure. The results were obtained through 'in situ' measurements using a gamma spectrometry system. The results ranged from 0.06 to 0.38 mSv/y, mean of 0.20 mSv/y. Due to the low value of the effective dose rate, we concluded that the area is characterized by low background radiation. Therefore, natural radioactivity is probably not directly influencing the increase in cancer incidence in the region. However, there is a need for complementary studies in this area to evaluate the dose from potential exposure to ingested and inhaled natural radionuclides from natural radioactivity in soil, rocks, vegetation and water.
Assuntos
Radiação de Fundo , Exposição Ambiental/análise , Neoplasias Induzidas por Radiação/epidemiologia , Monitoramento de Radiação/métodos , Poluentes Radioativos do Ar/análise , Algoritmos , Brasil/epidemiologia , Humanos , Incidência , Fatores de Risco , Poluentes Radioativos do Solo/análise , Espectrometria gama , Urânio/análiseRESUMO
The concentrations of As, Zn, Co, Cr, and Ba were determined in soil samples from an anomalous uranium ore region in the countryside of the state of Pernambuco, Brazil. The main land use system in this region is dairy farming, and there is a need to evaluate the potential risk of milk contamination. Twenty-three soil samples were activated with neutrons and analyzed using a high-resolution gamma-ray spectrometer system. The results, recorded in mg kg(-1), varied from 0.4 to 6.7 for As, from 17.0 to 110.0 for Zn, from 2.8 to 38.4 for Co, from 12.1 to 65.5 for Cr, and from 443.0 to 1,497.0 for Ba. All of the Ba concentrations were higher than the intervention value adopted by the Brazilian National Environmental Board. This finding justifies research in other environmental areas to predict the toxicological risks to the local population.