Avaliação da  radioatividade natural em areias das praias da Grande Vitória, Espirito Santo

Aquino, Reginaldo Ribeiro de

doi:10.11606/d.85.2010.tde-29082011-140012

Cited by 3 publications

(8 citation statements)

References 22 publications

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“…Areias de praias localizadas em regiões que possuem níveis de exposição superiores aos considerados "de fundo normal" apresentam altas concentrações de atividade de 226 Ra (radionuclídeo da série do 238 U), de 232 Th e de 40 K em estudos anteriores devido a fontes naturais de radiação. É o caso de areias de praias do Egito (Uosif et al, 2008;Eissa et al, 2010), da China (Xinwei e Zhang, 2008), da Turquia (Cevik et al, 2009), da Índia (Kannan et al, 2002), de Bangladesh (Alam et al, 1998) e do Brasil (Veiga et al, 2006, Aquino, 2010, e também em outros países como Austrália, Áustria, França, Irã, África do Sul, Tailândia e Sri Lanka (Andrade, 2011).…”

Section: Radioatividade Natural E Séries Radioativas Naturaisunclassified

“…J a n /1 1 Aquino, 2010 Aquino, 2010Veiga et al, 2005Veiga et al, 2005Sowmya et al, 2010Cevik et al, 2009 Xinwei e Zhang, 2008 Eissa et al, 2010 Os resultados deste trabalho estão dentro do intervalo de valores encontrados na literatura para areias semelhantes, provenientes de regiões com nível elevado de radiação natural.…”

Section: Concentração De Atividade De 232 Th Das Amostras De Areia Counclassified

“…Comparando os valores do atual trabalho com as de outras referências (TAB.6) observamos que os maiores valores encontrados para a concentração de atividade de 226 Ra e 232 Th são obtidos neste trabalho no ponto 5 da Praia de Camburi (em junho), maiores até do que os valores obtidos para a Praia da Areia Preta (Aquino, 2010).…”

Section: Concentração De Atividade De 232 Th Das Amostras De Areia Counclassified

“…Notamos que os valores em Camburi Norte, Camburi Central e Camburi Sul (Aquino, 2010) estão nas faixas de concentração encontradas neste trabalho.…”

Section: Concentração De Atividade De 232 Th Das Amostras De Areia Counclassified

“…A atividade equivalente em rádio (Ra eq ) calculada pela equação 8 TABELA 7 -Fração de areia utilizada em cada tipo de material de construção (Aquino, 2010).…”

Section: Atividade Equivalente Em Rádiounclassified

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Avaliação da variação da radioatividade natural em areias da praia de Camburi- Vitória- Espírito Santo com fatores climatológicos e geológicos da região

Barros¹

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The main contribution to the external exposure to humans comes from gamma emitting radionuclides in soils, especially the 40 K and 238 U and 232 Th series. In this work, the activity concentrations of 226 Ra (238 U serie), 232 Th and 40 K in surface sand monthly collected at 11 sites along the Camburi beach during the year 2011, selected to cover the entire length of the beach, were determined. The samples were hermetically sealed and measured by high resolution gamma spectrometry, after a resting time of approximately 30 days, in order to attain the radioactive equilibrium in the 238 U and 232 Th series. The activity concentration of 226 Ra was determined by the weighted average concentrations of 214 Pb and 214 Bi, the activity concentration of 232 Th by the weighted average concentrations of 212 Pb, 212 Bi and 228 Ac. The activity of 40 K was determined by its single transition of 1460,8 keV. For all samples the concentrations were corrected by self attenuation factors. From these concentrations, radiological indices like radium equivalent activity (Ra eq), activity concentration index (I γ), external exposure risk index (H ext), internal exposure risk index (H int), absorbed gamma dose rate in air (D) in nGy.h-1 and annual effective dose (E) in mSv.y-1 were evaluated. In the studied area it was realized an assessment of the correlation of the activity concentrations of 226 Ra, 232 Th and 40 K with the geological, geographical, climatological (rainfall and temperature) and oceanographic (tidal height variation) factors. Due to the strong presence of monazite, the concentration of 232 Th is higher than the concentration of 226 Ra and 40 K. The activity concentrations found ranged from 4 Bq.kg-1 to 1380 Bq.kg-1 for 226 Ra, from 9 Bq.kg-1 to 7453 Bq.kg-1 for 232 Th and 6 Bq.kg-1 to 504 Bq.kg-1 for 40 K. The variation of Ra eq from 20 Bq.kg-1 to 12077 Bq.kg-1 , of I γ from 0,07 to 42,08, of H ext from 0,05 to 32,61, of H int from 0,06 to 36,34 and of absorbed gamma dose rate in air from 9 nGy.h-1 to 5160 nGy.h-1. The low activity concentrations of 226 Ra, 232 Th and 40 K in all points in April , are possibly related to the maxima of the variation of the height of the tides and rainfall. The average temperature of Vitória during the year 2011 does not directly interfere in the observed variations in the activity concentrations of 226 Ra, 232 Th and 40 K sands. The assessment of the annual effective dose to an individual from the public who attends the Camburi Beach throughout 8 hours per day in a month, in January or July, showed that all values are below the limit of 1 mSv.y-1 , recommended by the ICRP 60 for the general public.

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Section: Radioatividade Natural E Séries Radioativas Naturaisunclassified

Section: Concentração De Atividade De 232 Th Das Amostras De Areia Counclassified

“…Notamos que os valores em Camburi Norte, Camburi Central e Camburi Sul (Aquino, 2010) estão nas faixas de concentração encontradas neste trabalho.…”

Section: Concentração De Atividade De 232 Th Das Amostras De Areia Counclassified

“…A atividade equivalente em rádio (Ra eq ) calculada pela equação 8 TABELA 7 -Fração de areia utilizada em cada tipo de material de construção (Aquino, 2010).…”

Section: Atividade Equivalente Em Rádiounclassified

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Avaliação da variação da radioatividade natural em areias da praia de Camburi- Vitória- Espírito Santo com fatores climatológicos e geológicos da região

Barros¹

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Avaliação da radioatividade natural em mármores e granitos comerciais do estado do Espírito Santo

Aquino¹

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In this work, the concentrations of natural radionuclides 226 Ra, 232 Th and 40 K in granite and marble samples were determined, considering the main extraction mining of Espirito Santo state, southeastern Brazil. For all study sites, three samples were sealed in 100 ml high density polyethylene bottles. Each sample rested for 4 weeks to reach the secular equilibrium of 238 U and 232 Th series before measured by high resolution gamma spectrometry, and the acquired spectra were analyzed with the software WinnerGamma. The self-absorption correction was considered for all samples, using an expression and method specially developed for this purpose. The concentration of 226 Ra was determined by the weighted arithmetic mean of the concentrations of 214 Pb and 214 Bi, the concentration of 232 Th by the weighted arithmetic mean of the concentrations of 228 Ac, 212 Pb and 212 Bi and the concentration of 40 K by its single 1460 keV transition. The radium equivalent and gamma index were calculated from the activity concentrations of 226 Ra, 232 Th, and 40 K. The emanated radon was measured using an exhalation chamber and the passive detector technique, with a solid state nuclear tracks detectors (SSNTD) being exposed in NRPB/SSI-H dosimeters. During exposure, a commercial detector CR-39 ® and a national plastic called Durolon ® were used, the last was characterized for this purpose using a technique called double exposure and sensitivity intrinsic factor. The characterized plastic was efficient for the application and the calibration factor corresponded to 1.60 ± 0.10 tracks•cm²•(kBq•mˉ³•day)ˉ¹ in relation to the CR-39 factor, equivalent to 2.8 ± 0.2 tracks•cm²•(kBq•mˉ³•day)ˉ¹. The detector showed a higher efficiency at a higher dose. The activities determined by passive detection varyed from 100 ± 10 Bq•m-³ up to 2400 ± 300 Bq•m-³, highlighting the biggest exhalation rates for granite Iberê Mombasa. Considering the marbles, activity values varyed from 80 ± 10 Bq•m-³ up to 200 ± 25 Bq•m-³ highlighting only the Cintilante and Branco Extra with higher values. The values obtained for surface exhalation rate were approximately equal, except for granites Iberê Mombasa and Iberê Prado with values above 1 Bq·m-2 ·h-1. The measures by gamma spectrometry showed that the 226 Ra concentrations varyed from 1.9±0.2 Bq.kg-1 up to 483±55 Bq.kg-1 , with the highest value for granite Iberê Mombasa. The 232 Th concentrations ranged from 3.2±0.4 Bq.kg-1 to 224±6 Bq.kg-1 , whose largest value was observed for the gray granite Corumbá. The 40 K concentrations ranged from 8.8±1.8Bq.kg-1 up to 1642±67 Bq.kg-1 , with the largest value observed for granite Iberê Vitara. The radio equivalent value showed that most samples can be defined as category I, below 370 Bq.kg-1 , except for the granites Cinza Corumbá, Iberê Crema Bordeaux and Iberê Mombasa that can be classified as class II (up to 740 Bq.kg-1). The evaluated granites show internal and external exposure rates below 1.0 mSv•yˉ¹ except the granites Cinza Corumbá, Iberê Crema Bordeaux and Iberê...

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Adaptations of a Mobile Lab for Analysis of Th-232 in Soil Samples Using Well-Type NaI (Tl) Scintillation Gamma Spectrometry

Oliveira¹,

Amorim²,

Santos³

et al. 2020

Braz. J. Rad. Sci.

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The identification of the occurrence of 232Th, by measuring the energies of the children radioisotopes 228Ac, 208Tl, 212 Bi and 212Pb, in their places of origin, using the Mobile Lab for Identification of Radiological and Nuclear Agents - LabMovelRN, by discriminating their environmental concentration normal and NORM [1] is important for the performance of the operational teams of the Brazilian Army Chemical, Biological, Radiological and Nuclear Defense Institute (IDQBRN), optimizing their time of action, and reducing the chain of custody of the sample. Due to the operational difficulty of using HPGe detectors in LabMovelRN, an adaptation is being carried out in the laboratory in order to allow the analysis of 232Th in soil samples by the gamma spectrometry technique using scintillation detectors [2] of NaI (Tl) type well as the characterization of the response of this scintillator detector in energy, resolution and energy efficiency up to 3,000 keV.

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Avaliação da radioatividade natural em areias das praias da Grande Vitória, Espirito Santo

Cited by 3 publications

References 22 publications

Avaliação da variação da radioatividade natural em areias da praia de Camburi- Vitória- Espírito Santo com fatores climatológicos e geológicos da região

Avaliação da variação da radioatividade natural em areias da praia de Camburi- Vitória- Espírito Santo com fatores climatológicos e geológicos da região

Avaliação da radioatividade natural em mármores e granitos comerciais do estado do Espírito Santo

Adaptations of a Mobile Lab for Analysis of Th-232 in Soil Samples Using Well-Type NaI (Tl) Scintillation Gamma Spectrometry

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