FERNANDA CAVALCANTE
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Resumo IPEN-doc 29172 Estimated absorbed dose rate in the non-human biota in different environmental scenarios2022 - NISTI, M.B.; MADUAR, M.F.; CAVALCANTE, F.; SAUEIA, C.H.R.Artigo IPEN-doc 29139 Assessment of natural radioactivity in bottled mineral water from Brazil2022 - NISTI, M.B.; NERY, A.D.; SAUEIA, C.H.R.; CAVALCANTE, F.The approach taken in the WHO Guidelines for controlling radiological hazards in public water supplies has two stages. The first is an initial screening for gross alpha and beta activity to determine whether the activity concentrations are below levels at which no further action is required; and if these screening levels are exceeded, investigation of the concentration of individual radionuclides and comparison with specific guidance levels. Mineral water is obtained directly from natural sources or by extracting groundwater, it is characterized by the quantity of mineral salts, trace elements and other constituents. The bottled water industry is present in the major regions of the world, and the population consumption has increased every year in Brazil and world, also increasing new mineral water mining sites, so it is necessary to constantly check the amount of radioactivity in mineral water. The aim of this study is to quantify the concentration of the natural radionuclides in the bottled mineral water consumed in São Paulo city. The bottled mineral water samples were purchased in a supermarket in São Paulo, with 23 different brands. The determination of gross alpha and beta activity concentration in bottled mineral water by Liquid Scintillation Counting measurement was performed using a 1220 Quantulus™ Ultra Low-Level Liquid Scintillation Spectrometer. The natural radionuclides (226Ra, 228Ra, 210Pb and 40K) were measured by gamma spectrometry, using an HPGe detector. The results obtained in this study can be used for a database on bottled mineral water radioactivity from Brazil.Artigo IPEN-doc 28657 Reducing the risk for the biota by reusing a NORM residue2022 - NISTI, M.B.; CAVALCANTE, F.; SAUEIA, C.H.R.; MAZZILLI, B.P.All biota is exposed to natural radiation, the soil being the major source of radionuclides. Phosphogypsum (PG) is classified as a NORM residue of the phosphate fertilizer industry, often used in agriculture, as a soil conditioner. This residue is stored in stacks by the phosphate industries, potentially posing environmental risks. The aim of this study is to compare the risk for the terrestrial and aquatic biota arising from the storage of PG residue in the environment with that arising from its reuse as soil amendment. For this purpose, typical Brazilian soils amended with PG and PG itself were leached with distilled water. The concentration of natural radionuclides in the soil samples were used to evaluate the risk for terrestrial and aquatic biota, using the ERICA Tool. The results for terrestrial biota exposed to soils amended with phosphogypsum showed a risk reduction of about 85%, when compared to the exposure arising from phosphogypsum stacks. Considering the aquatic biota, the results showed a risk reduction of about 46% when comparing to radionuclide concentrations in leachates from phosphogypsum and from the soils amended with phosphogypsum. A new risk reduction assessment was performed to determine exclusively the contribution of the application of PG to the soil using the soil without PG, the risk reduction for terrestrial biota was of 99% and aquatic biota was a 74% reduction. Finally, it can be concluded that the addition of phosphogypsum in soils reduces the risk quotient related to the exposure of terrestrial and aquatic biota, showing that this is a safe practice.Artigo IPEN-doc 28199 Counting time optimization for gamma-ray spectrometry analysis2021 - NISTI, M.B.; MADUAR, M.F.; SAUEIA, C.H.R.; CAVALCANTE, F.Artigo IPEN-doc 28187 Assessment of natural radioactivity in bottled mineral water from Brazil2021 - NISTI, M.B.; NERY, A.D.; SAUEIA, C.H.R.; CAVALCANTE, F.Artigo IPEN-doc 27849 Estimation of exposure levels of terrestrial biota and radiation exposure around IPEN’s facilities2021 - CAVALCANTE, F.; NISTI, M.B.; SAUEIA, C.H.R.Humans are exposed to natural radiation; soil is a major source of external and internal exposure of radiation. The aim of this study is to evaluate the exposure levels of terrestrial biota and to estimate the radiation exposure around Instituto of Pesquisas Energéticas e Nucleares (IPEN) facilities. The ERICA Tool was used to calculate the exposure levels of terrestrial biota; the estimation of radiation exposure for humans was determined using a model proposed by UNSCEAR and Excess Lifetime Cancer Risk. Six soil points were collected and their activity concentrations were measured by gamma spectrometry. Two soil points showed a risk coefficient greater than 1, suggesting that the screening dose ratio of 10μGy h-1 might be exceeding for the most exposed species, namely lichen and bryophytes, even though the activity concentration values of the analyzed radionuclides showed no evidence of soil contamination due to the atmospheric discharges of the IPEN facilities. Thus, the radioactive discharges in the soil from all facilities are negligible. Hence, the authors concluded that the ERICA Tool can be useful in assisting environmental radiological monitoring program for decision-making, especially regarding: points collected, sample types and sampling frequency.Artigo IPEN-doc 27192 Optimization of the gamma-ray spectrometry counting time based on uncertainties of radionuclides concentration in samples2020 - NISTI, M.B.; MADUAR, M.F.; SAUEIA, C.H.R.; CAVALCANTE, F.; MAZZILLI, B.P.This paper aims to propose an easy and fast method of optimization of the gamma-ray spectrometry counting time in determining natural radionuclides (210Pb, 212Pb, 214Pb, 212Bi, 214Bi and 228Ac) in order to minimize uncertainties in the concentration. The samples were measured by gamma-ray spectrometry with a hyper-pure germanium detector Canberra, 25% relative efficiency, effective resolution of 1.9 keV on the 1332.5 keV 60Co with associated electronics and coupled to a microcomputer. Multichannel Maestro A65-I model was used for spectrum acquisition and peak net area determination, and WinnerGamma/Interwinner 6.01 software was used for gamma-ray spectra analysis and to calculate the concentrations and associated uncertainties. The counting times used were 86,000 s and 150,000 s.Resumo IPEN-doc 27040 Activity concentrations of natural and artificial radionuclides in feline dry food2015 - CAVALCANTE, F.; PECEQUILO, B.R.S.; LEONARDO, L.Natural radiation exposure is an inherent condition to all living species, once radionuclides from the 238U and 232Th chain can nearly be found in all places. Information on radionuclides concentration and exposure levels, from natural and anthropogenic sources are absolutely necessary to investigate the possible effects that ionizing radiation can induce. These can be very different depending on the organism considered and the exposure pathway. In recent decades, the exposure of non-human species to ionizing radiation has been specially considered and investigated (ICRP, 2014) by a vast number of scientists and organizations, once they differ widely from the exposure of human beings. Brazil holds the second largest cat and dog population in the world, consuming over 2 million tons of feed every year. The country also stands out for its production of pet food that produced 2.4 million of tons of feed in 2014, representing the world’s second largest industry. A novel study regarding the radionuclide content in different dog and cat food is being developed since 2013 and preliminary results have been presented by Cavalcante, F. and Pecequilo (2014), for selected dry dog food. The present study presents an evaluation of the radionuclide and radioactivity content of different brands of dry cat food, commonly found in local markets in the city of Sao Paulo, Brazil. Thirteen different samples were crushed into powder and kiln dried before tightly sealed in 100 mL HDPE flasks, with a plan screw cap and bubble spigot. These samples, after resting for 30 days to ensure secular equilibrium, were placed in an extended range coaxial germanium detector (Canberra XtRa GX4020 detector) for 150 ks and the acquired spectra were analyzed with the InterWinner 6.0 software (InterWinner, 2004). The natural radionuclides considered were 238U, 232Th and 40K, the anthropogenic radionuclides investigated were 60Co, 131I, 137Cs and 134Cs. The results for the considered artificial radionuclides have shown activity concentration values below the detector’s MDA (Minimum Detectable Activity), as in Table 1. The concentrations of natural radionuclides ranged from 1.12 ± 0.29 Bq/kg to 3.77 ± 0.36 Bq/kg for 226Ra; from 1.48 ± 0.40 Bq/kg to 6.27 ± 0.78 Bq/kg for 232Th and from 216.8 ± 11.2 Bq/kg to 361.7 ± 16.8 Bq/kg for 40K, as shown in Figure 1. The results suggest that the samples evaluated have no contamination of artificial radionuclides and the natural radionuclides concentration will not contribute to significant absorbed dose by their ingestion. Therefore, the authors conclude that these studied brands carry no radiological risk for the animals ingesting them.Artigo IPEN-doc 26182 Estimation of exposure levels of terrestrial biota and radiation exposure around IPEN´s facilities2019 - CAVALCANTE, FERNANDA; NISTI, MARCELO B.; SAUEIA, CATIA H.R.Humans are exposed to natural radiation; soil is a major source of external and internal exposure of radiation. The external exposure from the soil is associated with gamma radiation and internal exposure mainly from radon inhalation. The aim of this study is to evaluate the exposure levels of terrestrial biota and to estimate the radiation exposure around IPEN facilities. The Institute comprises several nuclear and radioactive facilities including a research reactor, cyclotrons and a radioisotope and radiopharmaceutical production plant. The ERICA Tool was used to calculate the exposure levels of terrestrial biota; the estimation of radiation exposure for humans was determined using a model proposed by UNSCEAR (Absorbed dose rate in air and Annual effective dose equivalent) and Excess Lifetime Cancer Risk. Six soil points were collected and their activity concentrations were measured by gamma spectrometry, using a HPGe detector. Two soil points showed a risk coefficient greater than 1, suggesting that the screening dose ratio of 10μGy h 1 might be exceeding for the most exposed species, namely lichen and bryophytes, even though the activity concentration values of the analyzed radionuclides showed no evidence of soil contamination due to the atmospheric discharges of the IPEN facilities. Thus, the radioactive discharges in the soil from all facilities are negligible. Hence, the authors concluded that the ERICA Tool can be useful in assisting environmental radiological monitoring program for decision making, especially regarding: points collected, sample types and sampling frequency.Resumo IPEN-doc 25938 Self-attenuation factors in gamma-ray spectrometry of samples containing radionuclides of natural origin2018 - PECEQUILO, B.R.S.; CAVALCANTE, F.; BARROS, L.F.; FERREIRA, A.O.; FONSECA, L.M.; MATEUS, C.High resolution gamma-ray spectrometry is currently the most widely used analytical technique for qualitative and quantitative determination of radionuclides. Quantification of elements relies on the correct analysis of the spectra, depending strongly on the efficiency calibration of the measurement apparatus, most often performed with aqueous standard multi-radionuclide solutions. For efficiency calibration curves obtained by this method and for samples containing radionuclides of natural origin such as sand, soil, rocks and wall paint with apparent typical densities higher than that of water, self-attenuation correction factors were experimentally determined for hundreds of different samples using the Cutshall transmission technique. The results show that, to obtain more reliable analyses, correction factors for the self-attenuation behaviour, especially in the lower part of the energy spectrum, should be used. Since attenuation depends not only on the density of the sample but also on its chemical composition, correction factors have to be determined for each sample.