Natural radionuclide distribution in Brazilian commercial granites

Anjos, R. M.; Veiga, R.; Soares, Thais da Silva; Santos, A.M.A.; Aguiar, J.G.; Frascá, Maria Heloisa Barros Oliveira de; Brage, J.A.P.; Uzêda, D.; Mangia, L.; Facure, A.; Mosquera, B.; Carvalho, C. A. A. de; Gomes, P.R.S.

doi:10.1016/j.radmeas.2004.05.002

Cited by 149 publications

(94 citation statements)

References 6 publications

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“…The study included measurements of 39 slabs representing 27 types of granite estimated to account for approximately 30% of sales in the United States. In addition, the identity and geographic origin of the stones included in this study is not known precisely because naming practices for granite are not standardized (Anjos et al, 2005). Nonetheless, the activity concentrations for 40 K, and the 232 Th and 226 Ra series observed in these stones are within the range reported for granite building materials in the scientific literature (Mustonen, 1984;NCRP, 1987a;Mustapha et al, 1997;Chowdhury, Alam and Ahmed, 1998;European Commission, 1999;Lee, Kim, Lee and Kang, 2001;IAEA, 2003;Kumar, Sengupta and Prasada, 2003;Arafa, 2004;Ahmed, 2005;ICRP, 2005;Al-Saleh and Al-Berzan, 2007;El-Taher, Uosif and Orabi, 2007;Lu, Wang, Jia and Wang, 2007;Ghosh et al, 2008;Kitto, Haines and Diaz Arauzo, 2008;Mujahid et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

Assessing exposure to granite countertops—part 1: Radiation

Myatt¹,

Allen²,

Minegishi³

et al. 2009

J Expo Sci Environ Epidemiol

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Humans are continuously exposed to low levels of ionizing radiation. Known sources include radon, soil, cosmic rays, medical treatment, food, and building products such as gypsum board and concrete. Little information exists about radiation emissions and associated doses from natural stone finish materials such as granite countertops in homes. To address this knowledge gap, gross radioactivity, g ray activity, and dose rate were determined for slabs of granite marketed for use as countertops. Annual effective radiation doses were estimated from measured dose rates and human activity patterns while accounting for the geometry of granite countertops in a model kitchen. Gross radioactivity, g activity, and dose rate varied significantly among and within slabs of granite with ranges for median levels at the slab surface of ND to 3000 cpm, ND to 98,000 cpm, and ND to 1.5EÀ4 mSv/h, respectively. The maximum activity concentrations of the 40 K, 232 Th, and 226 Ra series were 2715, 231, and 450 Bq/kg, respectively. The estimated annual radiation dose from spending 4 h/day in a hypothetical kitchen ranged from 0.005 to 0.18 mSv/a depending on the type of granite. In summary, our results show that the types of granite characterized in this study contain varying levels of radioactive isotopes and that their observed emissions are consistent with those reported in the scientific literature. We also conclude from our analyses that these emissions are likely to be a minor source of external radiation dose when used as countertop material within the home and present a negligible risk to human health.

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Section: Discussionmentioning

confidence: 99%

Assessing exposure to granite countertops—part 1: Radiation

Myatt¹,

Allen²,

Minegishi³

et al. 2009

J Expo Sci Environ Epidemiol

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“…De acordo com WHO (2004), a razão entre 40 K e K total pode ser escrita como 27,6 Bq de atividade beta (devida ao 40 K) por grama de potássio total, queé equivalente a 276 Bq/kg. Contudo, ao invés da utilização destes fatores de conversão, com o propósito de comparar os resultados obtidos neste trabalho com aqueles referidos por Anjos et al (2005), serão adotados os seguintes valores para as atividades específicas: 1% K = 317 Bq/kg; 1 ppm eU = 13 Bq/kg; 1 ppm eTh = 4,08 Bq/kg. O emprego destes fatores de conversão permite calcular a taxa …”

Section: Avaliação Dosimétrica Das Rochasunclassified

“…Um outro fator correspondente a 0,7 Sv/Gy, expresso por UNSCEAR (1993) e adotado por Anjos et al (2005), pode também ser empregado para calcular a dose efetiva a partir da taxa de dose absorvida (T D A), estando os resultados obtidos (em mSv/ano) apresentados na Tabela 3. A dose efetiva varia de 0,45 a 7,19 mSv/ano e a análise estatística dos dados obtidos indica que os valores de dose seguem uma distribuição lognormal, conforme ilustrado na Figura 5, da mesma maneira como verificado para as distribuições das concentrações dos radioelementos (Fig.…”

Section: Avaliação Dosimétrica Das Rochasunclassified

“…No geral, os catálogos que têm sido produzidos para a descrição das características das rochas destinadasà comercialização apresentam sua coloração dominante, classificação petrográfica e principaisíndices físicos, sem haver, contudo, referência a qualquer nível de radioatividade (ABIROCHAS, 2008), queé um parâmetro que têm se constituído em barreira não alfandegária por parte de alguns paises importadores de granitos ornamentais do Brasil. Alguns estudos já têm sido realizados no Brasil visando caracterizar a radioatividade natural em rochas ornamentais (Salas et al, 2003;Moura et al, 2005;Anjos et al, 2005), porém, a maioria das amostras analisadas provém dos estados do Espírito Santo e Minas Gerais, cuja produção corresponde a quase 80% de todo o material destinadoà exportação.…”

Section: Introductionunclassified

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Dose de exposição radiométrica de granitos do estado de Rondônia, Brasil

Bonotto¹,

Júnior²,

Payolla³

et al. 2009

Rev. Bras. Geof.

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ABSTRACT. This work evaluated the activity concentration of the radioelements K, eU and eTh in samples of granites from Rondônia State, Brazil. The statistical analysis of the data indicated that they fit lognormal distributions. The modal values correspond to about 11% for K, 29 ppm for eU and 85 ppm for eTh. Direct significant correlations were found among the concentrations of the three radioelements, i.e. r = 0.71 (between K and eU), r = 0.72 (between K and eTh), and r = 0.72 (between eU and eTh), suggesting congruency of their accumulation in minerals occurring in the rocks analyzed. The activity concentration data allowed estimate the absorbed dose rate in air at 1 m above the ground, which also fits a lognormal distribution characterized by a mode of 2.7 mSv/y that is slightly higher than the average worldwide exposure of 2.4 mSv/y. The results obtained also allowed evaluate if the granites analyzed are radiometrically suitable as building and ornamental materials.Keywords: radioactivity, gamma exposure rate, granites. RESUMO.Este trabalho avaliou a concentração dos radioelementos K, eU e eTh em amostras de granitos do Estado de Rondônia, Brasil. A análise estatística dos dados obtidos indicou que eles seguem distribuições lognormais. Os valores modais encontrados correspondem a cerca de 11% para K, 29 ppm para eU e 85 ppm para eTh. Correlações diretas significativas foram determinadas entre as concentrações dos três radioelementos, istoé, r = 0,71 (entre K e eU), r = 0,72 (entre K e eTh) e r = 0,72 (entre eU e eTh), sugerindo que são congruentes os processos de seu acúmulo nos minerais das rochas analisadas. Os dados de concentração permitiram estimar a taxa de dose absorvida de radiação no ar acima de 1 m do nível do terreno, a qual também segue uma distribuição lognormal, com valor modal de 2,7 mSv/ano, queé ligeiramente superiorà média global de 2,4 mSv/ano. Os resultados obtidos também permitiram avaliar, do ponto de vista radiométrico, se os granitos analisados são adequados para emprego como revestimento em construção civil.Palavras-chave: radioatividade, dose de exposição gama, granitos.

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“…Natural radioactivity is associated with many different rocks, mainly due to the accessory minerals they contain (e.g. Whitfield et al, 1959;Anjos et al, 2005). Our rocks have a variety of minerals, some of them having radiogenic elements in their stoichiometric formulas and some being possible receptors of radiogenic elements owing to their mineral structure.…”

Section: Introductionmentioning

confidence: 99%

Radiological data on building stones from a Spanish region: Castilla y León

Pereira

Neves

et al. 2013

Nat. Hazards Earth Syst. Sci.

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Abstract. As construction and building material, natural stone has a great potential to promote the commercial activities of certain European regions. Such is the case of Castilla y León in Spain, where many different rocks, ranging from sedimentary to metamorphic and igneous, are commercialized for building purposes. However, to be able to compete in a market subject to an economic crisis, highly exacerbated in the construction sector, and to compete with the lower prices offered by emerging countries, the issue would be to make the Spanish offer more attractive. Here we propose a complete characterization of rocks regarding their radiological properties, which are related to their mineralogy and geochemistry. Rocks emit natural radioactivity, and the presence of Rn and its decay products in dwellings has become an important issue in North America and Europe owing to its relationship with the carcinogenic effects of this gas. Although most of the studied rocks comply with the I parameter proposed in the European Norm 112 for Radiological Protection (accepted value I ≤ 1; average for sedimentary rock: I = 0.22, SD 0.14; average for metamorphic rocks: I = 0.70, SD 0.48; average for igneous rock: I = 0.86, SD 0.22), the inclusion of a proper radiological characterization in the list of characteristics would guarantee quality and safety in their use in comparison with products lacking this information. Some natural stones have been demonized for the potential exhalation of natural radioactivity, and the different parameters used should be addressed in a more systematic way.

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Natural radionuclide distribution in Brazilian commercial granites

Cited by 149 publications

References 6 publications

Assessing exposure to granite countertops—part 1: Radiation

Assessing exposure to granite countertops—part 1: Radiation

Dose de exposição radiométrica de granitos do estado de Rondônia, Brasil

Radiological data on building stones from a Spanish region: Castilla y León

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