RESUMO
Annual effective dose due to the consumption of 40K, 226Ra, 228Ra and 228Th was estimated from high-resolution gamma spectrometry, food consumption data for the inhabitants of Rio de Janeiro City and dose coefficients published by the ICRP 119. A total of 31 samples of cereals, grains, vegetables, flours, liquid and perishables were analyzed. 40K was measured in all samples, and bean sample presented highest specific concentration 489.36 ± 23.70 Bq kg-1. The highest specific concentration for 226Ra, 228Ra and 228Th was measured in pumpkin (7.82 ± 1.09 Bq kg-1), carrot (30.18 ± 1.99 Bq kg-1) and beet (2.43 ± 0.48 Bq kg-1), respectively. The highest contribution to annual effective dose came from beans (556.3 µSv), potato (12.5 µSv), carrot (10.3 µSv), banana (4.7 µSv) and beet (3.3 µSv). It was observed that updates of daily food consumption values was the main reason for an up to 10-fold difference between the annual effective dose found in the present study and literature data.
Assuntos
Dieta , Contaminação Radioativa de Alimentos/análise , Radioisótopos de Potássio/análise , Rádio (Elemento)/análise , Tório/análise , Brasil , Humanos , Doses de Radiação , Exposição à Radiação , Monitoramento de RadiaçãoRESUMO
BACKGROUND: The ratio of male to female offspring at birth may be a simple and non-invasive way to monitor the reproductive health of a population. Except in societies where selective abortion skews the sex ratio, approximately 105 boys are born for every 100 girls. Generally, the human sex ratio at birth is remarkably constant in large populations. After the Chernobyl nuclear power plant accident in April 1986, a long lasting significant elevation in the sex ratio has been found in Russia, i.e. more boys or fewer girls compared to expectation were born. Recently, also for Cuba an escalated sex ratio from 1987 onward has been documented and discussed in the scientific literature. PRESENTATION OF THE HYPOTHESIS: By the end of the eighties of the last century in Cuba as much as about 60% of the food imports were provided by the former Soviet Union. Due to its difficult economic situation, Cuba had neither the necessary insight nor the political strength to circumvent the detrimental genetic effects of imported radioactively contaminated foodstuffs after Chernobyl. We propose that the long term stable sex ratio increase in Cuba is essentially due to ionizing radiation. TESTING OF THE HYPOTHESIS: A synoptic trend analysis of Russian and Cuban annual sex ratios discloses upward jumps in 1987. The estimated jump height from 1986 to 1987 in Russia measures 0.51% with a 95% confidence interval (0.28, 0.75), p value < 0.0001. In Cuba the estimated jump height measures 2.99% (2.39, 3.60), p value < 0.0001. The hypothesis may be tested by reconstruction of imports from the world markets to Cuba and by radiological analyses of remains in Cuba for Cs-137 and Sr-90. IMPLICATIONS OF THE HYPOTHESIS: If the evidence for the hypothesis is strengthened, there is potential to learn about genetic radiation risks and to prevent similar effects in present and future exposure situations.
Assuntos
Acidente Nuclear de Chernobyl , Exposição Ambiental , Contaminação Radioativa de Alimentos/análise , Radioisótopos de Césio/análise , Radioisótopos de Césio/metabolismo , Comércio , Cuba , Feminino , Humanos , Masculino , Monitoramento de Radiação , Radiação Ionizante , Federação Russa , Razão de Masculinidade , Radioisótopos de Estrôncio/análise , Radioisótopos de Estrôncio/metabolismo , Fatores de TempoRESUMO
This paper focuses on a survey of uranium and thorium decay chain radionuclides in food and drinking water from the thorium-rich (monazite-bearing) region of Buena, which is located in the state of Rio de Janeiro, Brazil. The radionuclide concentration values in the food and drinking water from Buena reached values higher than 100-fold the international reference values. The daily intake of radionuclides by the local population is similar to that of another high background radiation area in Brazil, but the intake is higher than that of residents from a normal background radiation area. Approximately 58 % of the food consumed by Buena inhabitants is produced locally. Based on that figure, locally produced food and the dilution of total radionuclides in the diet of residents caused by food importation are both highly relevant to a population's intake of radionuclides. The concentration values for (210)Pb and the radium isotopes in drinking water from Buena are among the highest values to be reported in the literature. (228)Ra is the most important radionuclide ingested with both food and water among the inhabitants of Buena.
Assuntos
Água Potável/análise , Contaminação Radioativa de Alimentos/análise , Poluentes Radioativos da Água/análise , Animais , Brasil , Humanos , Radioisótopos de Chumbo/análise , Metais Terras Raras , Doses de Radiação , Monitoramento de Radiação , Rádio (Elemento)/análise , Tório/análise , Urânio/análiseRESUMO
Radionuclides from the U and Th natural series are present in alkaline rocks, which are used as feedstock in Brazil for the production of raw phosphoric acid, which can be considered as a NORM (naturally occurring radioactive material). As a result of the purification of raw phosphoric acid to food-grade phosphoric acid, two by-products are generated, i.e., solid and liquid wastes. Taking this into account, the main aim of this study was to evaluate the fluxes of natural radionuclide in the production of food-grade phosphoric acids in Brazil, to determine the radiological impact caused by ingestion of food-grade phosphoric acid, and to evaluate the solid waste environmental hazards caused by its application in crop soils. Radiological characterization of raw phosphoric acid, food-grade phosphoric acid, solid waste, and liquid waste was performed by alpha and gamma spectrometry. The (238)U, (234)U, (226)Ra, and (232)Th activity concentrations varied depending on the source of raw phosphoric acid. Decreasing radionuclides activity concentrations in raw phosphoric acids used by the producer of the purified phosphoric acid were observed as follows: Tapira (raw phosphoric acid D) > Catalão (raw phosphoric acids B and C) > Cajati (raw phosphoric acid A). The industrial purification process produces a reduction in radionuclide activity concentrations in food-grade phosphoric acid in relation to raw phosphoric acid produced in plant D and single raw phosphoric acid used in recent years. The most common use of food-grade phosphoric acid is in cola soft drinks, with an average consumption in Brazil of 72 l per person per year. Each liter of cola soft drink contains 0.5 ml of food-grade phosphoric acid, which gives an annual average intake of 36 ml of food-grade phosphoric acid per person. Under these conditions, radionuclide intake through consumption of food-grade phosphoric acid per year per person via cola soft drinks is not hazardous to human health in Brazil. Considering these annual additions of (238)U, (226)Ra, (232)Th and (40)K, and since these radionuclide should be homogeneously distributed in the upper 10 cm of soils with an assumed apparent density of 1.5 g/cm(3), a maximum increase of 0.19 ± 0.03 Bq kg(-1) of soil is expected for (238)U and (234)U. Thus, the addition of solid waste as phosphate fertilizers to Brazilian agricultural soils does not represent a hazard to the ecosystem or to human health.
Assuntos
Elementos Radioativos/análise , Exposição Ambiental/efeitos adversos , Contaminação Radioativa de Alimentos/análise , Resíduos Industriais/análise , Ácidos Fosfóricos/análise , Radioisótopos de Potássio/análise , Poluentes Radioativos/análise , Agricultura , Brasil , Elementos Radioativos/toxicidade , Fertilizantes/análise , Manipulação de Alimentos , Humanos , Ácidos Fosfóricos/química , Ácidos Fosfóricos/toxicidade , Radioisótopos de Potássio/toxicidade , Poluentes Radioativos/toxicidade , Análise EspectralRESUMO
Polonium-210 ((210)Po) radioactive concentrations were determined in human semen fluid of vasectomized non-smoker volunteers. The (210)Po levels ranged from 0.10 to 0.39 mBq g(-1) (mean: 0.23 ± 0.08 mBq g(-1)). This value decreased to 0.10 ± 0.02 mBq g(-1) (range from 0.07 to 0.13 mBq g(-1)) after two weeks of a controlled diet, excluding fish and seafood. Then, volunteers ate during a single meal 200 g of the cooked mussel Perna perna L., and (210)Po levels were determined again, during ten days, in semen fluid samples collected every morning. Volunteers continued with the controlled diet and maintained sexual abstinence through the period of the experiment. A 300% increase of (210)Po level was observed the day following mussel consumption, with a later reduction, such that the level returned to near baseline by day 4.
Assuntos
Bivalves/efeitos dos fármacos , Contaminação Radioativa de Alimentos/análise , Polônio/toxicidade , Monitoramento de Radiação , Alimentos Marinhos/toxicidade , Sêmen/química , Sêmen/efeitos dos fármacos , Adulto , Animais , Bivalves/química , Bivalves/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Polônio/análise , Polônio/metabolismo , Medição de Risco , Sêmen/metabolismoRESUMO
The common use of phosphate fertilizers NPK and amendments in sugar cane crops in Brazilian agriculture may increase the (226)Ra, (232)Th and (40)K activity concentrations in soils and their availability for plants and human food chain. Thus, the main aim of this study was to evaluate the distribution of (226)Ra, (232)Th and (40)K in soils and sugar cane crops in the Corumbataí river basin, São Paulo State, Brazil. The gamma spectrometry was utilized to measure the (226)Ra, (232)Th and (40)K activity concentration in all samples. The soil-to-sugar cane transfer factors (TF) were quantified using the ratio between the radionuclide activity concentration in sugar cane and its activity concentration in soil. The results show that, although radionuclides incorporated in phosphate fertilizers and amendments are annually added in the sugar cane crops, if utilized in accordance with the recommended rates, their use does not lead to hazards levels in soils. The soil-to-sugar cane transfer of radionuclides occurred in the following order (40)K>(226)Ra>(232)Th. Therefore, under these conditions, radionuclides intake through consumption of sugar is not hazardous to human health.
Assuntos
Contaminação Radioativa de Alimentos/análise , Saccharum , Poluentes Radioativos do Solo/análise , Agricultura , Brasil , Potássio/análise , Radioisótopos/análise , Rádio (Elemento)/análise , Solo , Tório/análiseRESUMO
The objective of this study was to determine the 226Ra concentrations in samples of sugar cane juice, which is sold for human consumption in the city of Recife, capital of the state of Pernambuco, Brazil. The sample collections were carried out in seventeen commercial establishments where high quantities of the juice are usually sold. The methodology used to determine the concentrations of 226Ra in the juice was based on 222Rn emanation classical technique. Concentrations of 226Ra in the samples varied from 18 to 89 mBqL(-1).
Assuntos
Contaminação Radioativa de Alimentos/análise , Monitoramento de Radiação/métodos , Rádio (Elemento)/análise , Saccharum/química , Poluentes Radioativos do Solo/análise , Brasil , Preparações de Plantas/químicaRESUMO
The Southwest region of the Bahia state in Brazil hosts the largest uranium reserve of the country (100 kton in uranium, only), plus the cities of Caetité, Lagoa Real and Igaporã. In this work, aim was at the investigation of uranium burdens on residents of these cities by using teeth as bioindicators, as a contribution for possible radiation protection measures. Thus, a total of 41 human teeth were collected, plus 50 from an allegedly uranium free area (the control region). Concentrations of uranium in teeth from residents of 5- to 87-y old were determined by means of a high-resolution inductively coupled plasma mass spectrometer (ICP-MS). The highest uranium concentration in teeth was measured from samples belonging to residents of Caetité (median equal to 16 ppb). Assuming that the uranium concentrations in teeth and bones are similar within 10-20% (for children and young adults), it concluded that uranium body levels in residents of Caetité are at least one order of magnitude higher than the worldwide average. This finding led to conclude that daily ingestion of uranium, from food and water, is equally high.
Assuntos
Monitoramento Ambiental/métodos , Contaminação Radioativa de Alimentos/análise , Dente/química , Urânio/análise , Urânio/farmacocinética , Poluentes Radioativos da Água/análise , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Humanos , Masculino , Pessoa de Meia-Idade , Modelos BiológicosRESUMO
Radioactive lightning rods were manufactured in Brazil until 1989, when the licenses for using radioactive sources in these products were lifted by the national nuclear authority. Since then, these rods have been replaced by the Franklin type and collected as radioactive waste. However, only 20% of the estimated total number of installed rods has been delivered to the Brazilian Nuclear Commission. This situation causes concern, since there is the possibility of the rods to be disposed as domestic waste. In Brazil, 64% of the municipal solid waste is disposed at garbage dumps without sufficient control. In addition, (241)Am, the radionuclide most commonly employed, is classified as a high-toxicity element, when incorporated. In the present study, (241)Am migration experiments were performed by means of a lysimeter system, in order to evaluate the risk of contamination caused by radioactive lightning rods disposed as common solid waste. (241)Am sources removed from lightning rods were placed inside lysimeters filled with organic waste that was collected at the restaurant of the Instituto de Pesquisas Energéticas e Nucleares. The generated leachate was periodically analyzed, and characteristics such as pH, redox potential, solid content and the concentration of the radioactive material were determined. The equivalent dose for members of the public was calculated considering ingestion of contaminated drinking water as the major path of exposure. Estimated doses were about 20-times below the effective dose limit of 1 mSv year(-1) for members of the public as recommended by the International Commission on Radiological Protection. This suggests the radiation risk caused by lightning rods disposed at uncontrolled garbage dumps to be low. It should be noted, however, that the number of investigated lightning rods was quite small. The results of this study might therefore not be entirely representative and should be interpreted with care. They provide, however, a very first basis for characterizing the transfer of (241)Am from lightning rods to the human food chain.
Assuntos
Amerício/análise , Contaminação Radioativa de Alimentos/análise , Resíduos de Alimentos , Amerício/efeitos adversos , Brasil/epidemiologia , Exposição Ambiental/efeitos adversos , Substâncias Perigosas/efeitos adversos , Substâncias Perigosas/análise , Humanos , Resíduos Industriais/efeitos adversos , Resíduos Industriais/análise , Monitoramento de Radiação , Resíduos Radioativos/efeitos adversos , Resíduos Radioativos/análise , Radioisótopos/efeitos adversos , Radioisótopos/análise , Medição de Risco , Poluentes Químicos da Água/análise , Contaminação Radioativa da Água/efeitos adversos , Contaminação Radioativa da Água/análiseRESUMO
This work is aimed at determining (226)Ra concentration in cheese produced by dairy manufacturers from Pedra and Venturosa, which are two districts in the rural region of Pernambuco-Brazil. Analyses showed concentrations of (226)Ra in cheese samples varying from 54 to 2,080 mBq kg(-1) (wet matter). Using the cumulated risk method, the excess carcinoma and bone sarcoma were estimated for chronic ingestion of cheese containing this radioisotope. In this context, this report discusses the methodology of sample analyses as well as possible consequences of the (226)Ra intake for human health.
Assuntos
Queijo/análise , Contaminação Radioativa de Alimentos/análise , Poluentes Radioativos/análise , Rádio (Elemento)/análise , Neoplasias Ósseas/epidemiologia , Neoplasias Ósseas/etiologia , Brasil , Carcinoma/epidemiologia , Carcinoma/etiologia , Monitoramento Ambiental , Monitoramento Epidemiológico , Poluentes Radioativos/toxicidade , Rádio (Elemento)/toxicidade , Medição de Risco , Sarcoma/epidemiologia , Sarcoma/etiologia , Neoplasias Cranianas/epidemiologia , Neoplasias Cranianas/etiologiaRESUMO
Dentre os diversos agentes existentes no meio ambiente que podem nos expor a diferentes riscos e efeitos, há a radiação ionizante cujo conhecimento da dose é de importância para o efetivo controle e prevenção dos seus possíveis danos aos seres humanos e ao ambiente. A transferência de radionuclídeos dos adubos para/e dos solos para os alimentos podem resultar em incremento na dose interna ao serem consumidos pelo ser humano. Este trabalho avalia a contribuição dos fertilizantes para o aumento da dose de radiação ionizante no meio ambiente e no ser humano. Amostras de fertilizantes, de solos e de hortaliças produzidas em solos adubados foram analisadas através da espectrometria gama com o uso de um detector semicondutor de germânio hiperpuro. Medidas de dose ambiente também foram realizadas com dosímetros termoluminescentes. Nas amostras de solos adubados foram obtidos valores de atividades específicas de 36 a 342 Bq/kg para K-40, de 42 a 142 Bq/kg para U-238 e de 36 a 107 Bq/kg para Th-232. Nas hortaliças os valores variaram de 21 a 118 Bq/kg para K-40 e para os elementos da série do urânio e tório os valores foram menores que 2 Bq/kg. Para fertilizantes o valor máximo obtido foi de 5800 Bq/kg para K-40, 430 Bq/kg para U-238 e 230 Bq/kg para Th-232. As médias dos valores de fator de transferência solo-planta não foram significativamente diferentes entre os tipos de hortaliças analisados. A dose efetiva comprometida anual de 0,882 µSv devido à ingestão de K-40 das espécies estudadas é bem pequena em relação ao valor de referência de 170 µSv dada pela United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR, 2000). A dosimetria termoluminescente forneceu valores de taxa de equivalente de dose ambiente anual entre 1,5 e 1,8 mSv, sem diferenças entre locais cultivados e não cultivados. Através dos resultados obtidos, não foi observada uma transferência significativa de radionuclídeos dos fertilizantes para os alimentos e para os solos nas condições adotadas neste trabalho e conseqüentemente não há incremento de dose de radiação devido à prática da adubação.
Assuntos
Fertilizantes/efeitos adversos , Radiação Ionizante , Radioisótopos , Exposição Ambiental , Contaminação Radioativa de Alimentos , Exposição Ocupacional , Plantas , Medição de Radiação , Riscos de Radiação , Poluentes Radioativos do SoloRESUMO
A worker provided a routine faecal sample for plutonium and americium analysis. In the course of this analysis 500 mBq of (228)Th was discovered. There seemed no credible occupational route for intake of thorium. Further investigation revealed that the worker consumed approximately 25 g d(-1) of nuts, including Brazil nuts. A sample of these nuts was analysed and found to contain activities of (228)Th in sufficient quantity to account for the faecal activity. However, follow-up urine samples taken from the worker showed 0.6-0.7 mBq of (228)Th. The intake of (228)Th via nuts is insufficient to account for this activity in urine. However, it is likely that the intake of (228)Th was accompanied by similar activity of the parent (228)Ra, and biokinetic calculations show that decay of (228)Ra in vivo would produce sufficient (228)Th to account for the observed urine activity.
Assuntos
Bertholletia/química , Ingestão de Alimentos , Fezes/química , Contaminação Radioativa de Alimentos/análise , Tório/urina , Adulto , Carga Corporal (Radioterapia) , Humanos , Masculino , Taxa de Depuração Metabólica , Eficiência Biológica Relativa , Tório/análiseRESUMO
Natural levels of uranium in the diet of São Paulo City residents were studied, and radionuclide concentrations were measured by the fission track method on samples of typical adult food items. This information was used to evaluate the daily intake of uranium in individuals living in São Paulo City which is, according to our findings, around 0.97 microg U/day. Using the ICRP Uranium-model, we estimated the uranium accumulation and committed doses in some tissues and organs, as function of time. We compared the output of the ICRP uranium biokinetic model, tailored for the conditions prevailing in São Paulo, with experimental data from other localities. Such comparison was possible by means of a simple method we developed, which allows normalization among experimental results from different regions where distinct values of chronic daily intake are observed.
Assuntos
Dieta , Contaminação Radioativa de Alimentos/análise , Urânio/análise , Adulto , Brasil , Cidades , Feminino , Análise de Alimentos/métodos , Humanos , Masculino , Urânio/farmacocinéticaRESUMO
Studies for the determination of radionuclide concentrations in foodstuffs, water and air were carried out in Cuba for the estimation of annual committed effective doses to members of the public as a result of environmental radionuclides via ingestion and inhalation. As a result of these studies, it was possible to determine the concentrations of 226Ra, 210Pb, 210Po, 232Th, 90Sr and 137Cs in different food groups that constitute the diet of the Cuban population, as well as the 222Rn concentrations in air. Based on these results and using previously obtained results for doses due to the 40K body content, the annual committed effective doses due to the intake of studied radionuclides were estimated. An average value of 120+/-4 microSv y-1 was obtained for doses due to ingestion of food and water and the obtained value for 222Rn inhalation was 240+/-1 microSv y-1. Using the representative value obtained previously for 40K (150+/-40 microSv y-1) and assuming a dose of 50+/-50 microSv y-1 for the probable contribution of 220Rn by inhalation, a representative value of 560+/-20 microSv was estimated for the average annual committed effective doses due to ingestion and inhalation of radionuclides for the Cuban population. Obtained values are consistent with the expected results, taking into account the characteristics of Cuban exposure scenarios, with low-activity concentration levels in environmental objects and high air exchange rates in dwellings: These results are in the same order of magnitude as results obtained by other authors and the reference values established by the USNCEAR.
Assuntos
Poluentes Radioativos do Ar/análise , Exposição Ambiental , Contaminação Radioativa de Alimentos/análise , Radioisótopos/análise , Poluentes Radioativos da Água/análise , Adolescente , Adulto , Carga Corporal (Radioterapia) , Criança , Pré-Escolar , Cuba , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Grupos Populacionais , Doses de Radiação , Monitoramento de RadiaçãoRESUMO
The phosphate region located in the Northeast of Brazil covers an area of approximately 150 km long with an average width of 4 km, along the coast of the states of Pernambuco and Paraíba. The inhabitants of this area are exposed to natural radioactivity levels higher than the background values recorded in the literature, mainly due to the presence of uranium and its decay products in the phosphatic sediments. The main aim of this study was to determine the activity concentration of uranium and (226)Ra in foodstuffs cultivated in this area, where the phosphate mineral has been extracted. The activity concentrations found for uranium and (226)Ra in the foodstuffs analyzed varied from 13 to 186 mBq kg(-1) (wet weight), with a mean value of 46 mBq kg(-1) and from 43 to 2209 mBq kg(-1) (wet weight), with a mean value of 358 mBq kg(-1), respectively. The annual intake of these radionuclides, for rural residents, was 7.45 Bq for uranium and 69.3 Bq for (226)Ra.
Assuntos
Produtos Agrícolas/química , Contaminação Radioativa de Alimentos , Rádio (Elemento)/análise , Poluentes Radioativos do Solo/análise , Urânio/análise , Brasil , Humanos , Magnoliopsida/química , Fosfatos , Doses de RadiaçãoRESUMO
The comet assay is one of the most versatile and popular tools for evaluating DNA damage. Its sensitivity to low dose radiation has been tested in vitro, but there are limited data showing its application and sensitivity in chronic exposure situations. The influence of the internal contamination caused by the Chernobyl accident on the level of DNA damage was evaluated by the comet assay on lymphocytes of 56 Ukrainian children. The study was performed during 2003 on children with demonstrable 137Cs internal contamination caused by food consumption. The children were selected for the study immediately after a 137Cs whole body counter measurement of internal contamination. The minimal detectable amount of 137Cs was 75 Bq. The control group included 29 children without detectable internal contamination, while in the exposed group 27 children with measured activity between 80 and 4037 Bq and committed effective dose between 54 and 3155 microSv were included. Blood samples were taken by a finger prick. The alkaline version of the comet assay was used, in combination with silver stained comets and arbitrary units (AU), for comet measurement. Factors such as disease, medical treatment, surface contamination of children's living location, etc., were considered in the study. Non-significant differences (p > 0.05) in DNA damage in control (9.0 +/- 5.7 AU) versus exposed (8.5 +/- 4.8 AU) groups were found. These results suggest that low doses of 137Cs internal contamination are not able to produce detectable DNA damage under the conditions used for the comet assay in this study. Further studies considering effects of high exposure should be performed on chronically exposed people using this assay.
Assuntos
Radioisótopos de Césio/sangue , Acidente Nuclear de Chernobyl , Ensaio Cometa/métodos , Dano ao DNA , Linfócitos/fisiologia , Linfócitos/efeitos da radiação , Adolescente , Criança , Relação Dose-Resposta à Radiação , Feminino , Contaminação Radioativa de Alimentos , Humanos , MasculinoRESUMO
This work presents the results of the determination of uranium concentration in the most commonly used phosphate fertilizers employed in Brazilian agricultural land. The technique employed was the nuclear fission track registration in plastic foils of Makrofol KG (dry method), together with a discharge chamber system for track counting. Phosphate fertilizer samples and uranium standards were irradiated together with thermal neutrons in the 2 MW IEA-R1 research reactor of IPEN/SP. The uranium concentration in Brazilian phosphate fertilizers ranging from 5.17 to 54.3 ppm is in good agreement with the results reported in the literature for similar fertilizers produced in other countries.
Assuntos
Fertilizantes/análise , Manufaturas/análise , Radiometria/instrumentação , Radiometria/métodos , Urânio/análise , Brasil , Contaminação Radioativa de Alimentos/análise , Contaminação Radioativa de Alimentos/prevenção & controle , Radiometria/estatística & dados numéricos , Contagem de Cintilação/instrumentação , Contagem de Cintilação/métodosRESUMO
The metrological capability of 24 Brazilian laboratories of radionuclide determinations in environmental samples was analysed for purposes to establish requirements for accreditation of laboratory for each radionuclide. For each type of analysis, the range of activity per unit mass or volume, the range of the reference value and its correspondent uncertainty were described. The accuracy was established using the statistical criteria of USE.P.A. for the laboratory performance classification. The precision of the analyses, expressed by its variation coefficient of the laboratory determinations, was classified in intervals of 5%. The data base was constituted by 3013 results of analyses obtained in 28 intercomparison runs performed from 1991 to 2000, for K, Th, Unat, gross alpha, gross beta, and other 27 radionuclides, in matrices of water, soil, vegetation, air filter and milk. The quality criteria established were the variation coefficient less than 5% and good performance in intercomparison runs. Results included from 5% to 10% are also considered, for special types of matrices and radionuclides.
Assuntos
Poluentes Radioativos/análise , Radioisótopos/análise , Poluentes Radioativos do Ar/análise , Animais , Brasil , Contaminação Radioativa de Alimentos/análise , Humanos , Laboratórios/normas , Leite/química , Poluentes Radioativos/normas , Radioisótopos/normas , Poluentes Radioativos do Solo/análise , Tecnologia Radiológica , Poluentes Radioativos da Água/análiseRESUMO
One of the input ways of radionucleids into the organism is through food intake. The aim of the present study is to measure the radioactivity levels in food and water samples within energy windows corresponding to 137Cs, 125I, 131I, 59Fe, and 57Co. Samples were taken from local and imported food belonging to the venezuelan basic alimentary basket and included: beef meat, hen egg, chicken bone, tomato, black bean, rice, powder milk from local dealers or imported from Italy and New Zeeland, potable water from the Valencia city aqueduct and bottled water from local sources or imported from Portugal. Radioactivity was measured with a well type Nal (TI) scintillation counter. Analyzed foods and water presented levels lower than the minimal detectable activity for 137Cs, 131I, 59Fe, 57Co, but it was detected in the Valencia city aqueduct water and in bottled water imported from Portugal, levels greater than the minimal detectable activity for the 125I energy window. These results strongly suggest the need of repeated multienergy windows monitoring of radioactivity of basic alimentary basket foods and potable water.
Assuntos
Análise de Alimentos , Contaminação Radioativa de Alimentos , Alimentos/efeitos da radiação , Radioisótopos/análise , Água/química , Animais , Radioisótopos de Césio/administração & dosagem , Radioisótopos de Césio/análise , Radioisótopos de Cobalto/administração & dosagem , Radioisótopos de Cobalto/análise , Irradiação de Alimentos , Radioisótopos do Iodo/administração & dosagem , Radioisótopos do Iodo/análise , Radioisótopos de Ferro/administração & dosagem , Radioisótopos de Ferro/análise , Leite/efeitos da radiação , Radioisótopos/administração & dosagem , VenezuelaRESUMO
Self-absorption was measured for the activity calculation of the 1460.8 and 2614.47 keV lines of the 40K and the 208Tl, respectively, in powdered milk samples. Five Marinelli beakers were prepared with powdered milk in different degrees of compaction and the spectra were measured with an HPGe detector. The detection efficiency versus density was obtained and the self-absorption correction factors versus density were calculated for powdered milk. The results obtained show that this factor must be considered in the calculations of activities.