Radioanalytical models applied to the investigation of caesium signatures in sugar samples.

The presence of anthropogenic radioisotopes in the environment may be due to inappropriate discards, nuclear tests and accidents, which requires and justifies constant monitoring to ensure the safety of nuclear applications. The radiometric analysis is a necessary condition for exporting sugar for world consumption. The investigation of 134Cs and 137Cs in a sugar matrix is required to predict radiometric anomalies. This work aimed to standardise a semi-empirical radiometric model to characterise and quantify caesium isotopes in sugar. The research was carried out with high-resolution gamma spectrometry, a non-destructive method. The results were applied to the analysis of different types of sugar for export. The models allowed us to determine with excellent resolution the minimum quantifiable activities of 0.74 Bq kg-1 and 0.48 Bq kg-1 for 134Cs and 137Cs, respectively, which are lower than 600 Bq kg-1, reference values adopted by the EU for isotopes in food.

Determination of the internal dose due to the intake of 226Ra and 210Pb in drinking water from deep wells in the Metropolitan Region of Recife-Brazil.

The Metropolitan Region of Recife, the capital of the state of Pernambuco in northeastern Brazil, has a high demographic density and developed under a region of marine phosphorus with high concentrations of phosphate that naturally contains uranium ore, producing ionizing radiation from descendants of the radioisotope 238U where 226Ra and 210Pb are of great importance in verifying the probable harmful effects on human health due to environmental radioactivity. The supply of drinking water is the responsibility of the state-owned company COMPESA which uses wells of great depth to complete the supply of drinking water for the entire population. COMPESA and the RAE Group of the Federal University of Pernambuco developed a joint project to assess the concentrations of 226Ra and 210Pb and estimate the equivalent and effective doses caused by ingesting these radiation sources. According to the above, this research aimed to evaluate concentrations of 226Ra and 210Pb in drinking water samples from 110 deep wells in Recife. The activities of 226Ra and 210Pb ranged from 1.4 ± 0.3 to 119.3 ± 12.9 and from 25.6 ± 3.3 to 563.2 ± 45.6 mBq.L-1, with arithmetic means of 48.1 ± 3.8 and 231.1 ± 20 mBq.L-1, respectively. The equivalent doses average in bone tissue due to 226Ra and 210Pb were 0.45 ± 0.04 and 3.9 ± 0.37 mSv.y-1, and the annual average effective doses were 0.01 ± 0.00 and 0.13 ± 0.01 mSv.y-1, respectively.

Anthropogenic accumulation based on chemometrics of the radionuclide K-40 in tropical soils in the northeast Brazil.

The continuous use of fertilizers can increase the radionuclides levels in soils, and their accumulation and concentration are related to their characteristics and the various processes of use and soil occupation. Analyzing data from radiometric and pedological measurements often demands the use of more robust tools for better integration of results. This work presents the results of a study to evaluate the accumulation of 40K, in an area of the Zona da Mata region in Pernambuco, Northeastern Brazil, due to the contribution of natural or artificial sources. 40K activity concentration was measured by high resolution gamma spectrometry in 108 soil samples, as well the organic matter content and particle size distribution. Results showed the 40K activity ranged from 103 to 1843 Bq.Kg-1, with the arable soils showing levels above the world average value (420 Bq.Kg-1). A higher prevalence of 40K was observed on arable soils, regardless of soil type, organic matter content, depth or texture. Agricultural activities increased of 40K levels in different degrees, depending on the type of crop used, with an accumulation factor of up to 4 times greater compared to soils not impacted by agricultural activities. The radiochemometric diagnosis maded it possible to draw up a strategic management plan to improve the management practices of family farming in order to maximize production efficiency, and promote the conservation of natural resources and environmental preservation.

Influx of radioactive gas in norm occurrences in Northeastern Brazil.

Radon and progeny are potentially relevant in radioecological studies, as they contribute more than half of the exposure to environmental radiation. The investigation of 222Rn in internal environments of municipalities of Paraíba and Rio Grande do Norte in Brazil was carried out using passive dosimetry with α Espec-222, installed in environments selected by the history of natural radiative occurrences. The monitoring time was eight months to consider seasonal influence. Concentrations from 26.91 to 316.35 Bq m-3 were obtained, with a maximum effective dose of almost 8 mSv y-1. The influence on households exceeds, by almost 31%, the average obtained for occupational environments. The municipalities of Paraíba presented higher results for Rn, with an average of almost 176 Bq m-3 and an effective dose greater than 4 mSv y-1. The application of individual occupancy factors for home and work environments made it possible to combine the dosimetric models, making the scenario closer to the real exposure of individuals who work and reside in the same municipality, with a dosimetric response of 21.45% lower than the model used worldwide. The different scenarios applied allowed expanding the radiometry of the environments, generating a database that precedes studies of environmental and radioecological impacts, strengthening security and enabling new works to interpret public health problems in search of joint and shared solutions.

Evaluation of the action of LPSF/GQ-16 on cytokines and PPAR-γ gene expression after in vitro irradiation of peripheral blood mononuclear cells.

PURPOSE: Patients submitted to radiotherapy (RT) may present in their healthy tissues surrounding the treated tumor, some typical acute inflammatory reactions induced by ionizing radiation (IR). The manifestation of inflammatory processes is a result of exacerbation of the immune system, as a response to radiation exposure, and this can be a limiting factor for RT protocols. To counteract this, some thiazolidinediones, such as LPSF/GQ-16, may be useful for modulating the patient's radioinduced inflammatory response in normal tissues. In this context, the present work aims to evaluate the activity of LPSF/GQ-16 on the levels of cytokines and the expression of the gene PPARγ in mononuclear cells irradiated in vitro, to analyze the immunomodulatory activity of the molecule and its action on radiomitigation. MATERIALS AND METHODS: For this, blood samples from eight donors were collected and irradiated with 2 Gy, then the PBMC (peripheral blood mononuclear cells) were cultured and treated with LPSF/GQ-16. The levels of cytokines TNF-α, IFN-γ, IL-2 and IL-4 were quantified by CBA, while the genes of TNF-α, IFN-γ and PPARγ were analyzed by RT-PCR. RESULTS: LPSF/GQ-16 significantly reduced the expression of proinflammatory cytokines (IFN-γ and TNF-α) in irradiated and nonirradiated groups. There was no significant reduction of anti-inflammatory cytokines (IL-2 and IL-4) by LPSF/GQ-16. The mRNA expression of PPAR-γ, IFN-γ and TNF-α in the presence of LPSF/GQ-16 was higher in the nonirradiated sample. CONCLUSION: LPSF/GQ-16 showed effective activity after irradiation, with an important immunomodulatory activity in irradiated PBMCs.

α Espec-222 as a variant to the radon monitoring method using a solid state nuclear track.

Radon is important in indoor radiometry, where radiological impact is relevant. The improvement of low-cost methods makes it possible to maximize the monitored areas. Thus, a simple and robust monitoring device based on SSNTD CR-39 was designed. Detector conditions were standardized to reduce operational errors and increase productivity. The calibration factor by the slope method allowed efficiency greater than 93%. The monitoring system is satisfactory in terms of operation and performance, suitable for a wide range of radon monitoring situations.

Metal contaminants in rice from Cuba analyzed by ICP-MS, ICP-AES and CVAAS.

Mercury, lead, cadmium and arsenic are considered hazardous pollutants in the environment, which can result in a risk for human health. This study aimed to determine the contents of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn by ICP-MS, CVAAS and ICP-AES in paddy and brown rice, grown in different soils of Cuba. The interest to include Cr, Ni, Cu and Zn was because these elements are found in very high levels in agricultural soils. To assess the safety of the dietary intake of these metals, the estimated weekly intake was calculated. The contents of Cd and As were below the maximum limits. A higher value was obtained for Pb when compared to Codex Alimentarius limits. The weekly intake of Cr and Ni was higher than the maximum weekly intake recommended by FAO/WHO.

MONITORING AND CHARACTERISATION OF NEW EVIDENCE OF NATURAL RADIONUCLIDES IN ROCK OUTCROPS IN PARAÍBA-BRAZIL.

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.

RADIOACTIVE DISEQUILIBRIUM AND DYNAMIC OF NATURAL RADIONUCLIDES IN SOILS IN THE STATE OF PERNAMBUCO-BRAZIL.

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.

ENVIRONMENTAL IONIZING RADIATION DOSE OUTDOOR IN AN INHABITED AREA WITH A HIGH CONCENTRATION OF URANO-PHOSPHATE IN NORTHEAST OF BRAZIL.

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.

THERMOLUMINESCENT DOSIMETRY IN THE EVALUATION OF NATURAL RADIOACTIVITY INDOOR OF HOMES NEAR THE URANIUM DEPOSIT OF PARAÍBA, BRAZIL.

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.

EDXRF as an alternative method for multielement analysis of tropical soils and sediments.

The quality assessment of tropical soils and sediments is still under discussion, with efforts being made on the part of governmental agencies to establish reference values. Energy dispersive X-ray fluorescence (EDXRF) is a potential analytical technique for quantifying diverse chemical elements in geological material without chemical treatment, primarily when it is performed at an appropriate metrological level. In this work, analytical curves were obtained by means of the analysis of geological reference materials (RMs), which allowed for the researchers to draw a comparison among the sources of analytical uncertainty. After having determined the quality assurance of the analytical procedure, the EDXRF method was applied to determine chemical elements in soils from the state of Pernambuco, Brazil. The regression coefficients of the analytical curves used to determine Al, Ca, Fe, K, Mg, Mn, Ni, Pb, Si, Sr, Ti, and Zn were higher than 0.99. The quality of the analytical procedure was demonstrated at a 95% confidence level, in which the estimated analytical uncertainties agreed with those from the RM's certificates of analysis. The analysis of diverse geological samples from Pernambuco indicated higher concentrations of Ni and Zn in sugarcane, with maximum values of 41 mg kg- 1 and 118 mg kg- 1, respectively, and agricultural areas (41 mg kg- 1 and 127 mg kg- 1, respectively). The trace element Sr was mainly enriched in urban soils with values of 400 mg kg- 1. According to the results, the EDXRF method was successfully implemented, providing some chemical tracers for the quality assessment of tropical soils and sediments.

Characterization of heavy metals in a uranium ore region of the state of Pernambuco, Brazil.

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.