Radiological Survey in Soil of South America

M.L. MONTES; J. DESIMONI

Radioisotopes/Book 1

InTech

Lugar: Rijeka; Año: 2011; p. 197 - 224

Radiological surveys in soils and groundwater of South America María Luciana Montes, Alina Zaporojets and Judith Desimoni Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata Instituto de Física La Plata ? CONICET, La Plata, Argentina Abstract Although the Earth?s crust is naturally radioactive, natural and man-made nuclides have radiobiological implication due they are a significant part of human external radiation exposure and can contributed to the internal exposure by inhalation and ingestion [Cooper et al., 2003; UNSCEAR, 2008]. In the 60´s the nuclear power production and nuclear weapons testing supply achieved a 7% of the total dose, at the present they are a very small fraction of the total dose. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) has estimated that exposure to natural sources contributes with more than 98% to the radiation dose to the population (excluding medical exposure) [UNSCEAR, 2000; UNSCEAR, 2008]. Depending on factors such as height over sea level, amount and type of radionuclides in the soil, air, food, and water, the local doses varies worldwide. In consequence, before assessing the radiation dose to the population, a precise knowledge of the activity of a number of radionuclides is required. Therefore, the determination of radionuclides in environmental samples becomes an important task in protecting human health and to establish regulations [UNSCEAR, 2000; UNSCEAR, 2008]. Additionally, the mobility of the radionuclide in the ecosystem involves a number of complex mechanisms [Velasco et al., 2006; IAEA, 2010; Salbu, 2009; Cooper et al., 2003], and the transfer of radionuclides through the environmental compartments implies multiple interactions between the biotic and abiotic components of the ecosystem, as well as human interferences like the use of fertilizer [Tomazini da Conceic & Bonotto, 2006] or the overexploitation of the natural resources. To the identification of these interactions it is necessary to develop and test predictive models describing the radionuclide fluxes from the environment to the man. For South America, the UNSCEAR reports only account values of the activity concentration of the natural nuclide 40K for Argentina [UNSCEAR, 2000; UNSCEAR, 2008]. In the Brazilian State of Rio Grande do Norte the average concentrations of 226Ra, 232Th and 40K in unperturbed soils have been determined [Malanka et al., 1996]. In Argentina data of 226Ra and 40K of semi-natural grassland soils of the central part of the country (Province of San Luis) have been accounted [Juri Ayub et al., 2008]. Recently, the first systematic studies to establish baseline activities for the naturally (40K, 238U and 232Th chains) occurring radionuclides in unperturbed soils of inland and coastal areas around La Plata city, Province of Buenos Aires, have been settled on samples taken from the surface down to a depth of 50 cm [Montes et al. 2010a, 2010b]. Regarding the anthropogenic nuclides, only a few studies dealing with the determination of the activity of the 137Cs, globally presented on the soil because of nuclear weapon tests that have been performed in the Southern Hemisphere [Correchel et al., 2005; Handl et al., 2008]. Total inventories and depth distributions of 137Cs were established in the Central and Southerm agricultural sheep-farming regions of Chile [Schuller et al., 1997, 2002, 2004]. In Venezuela, the 137Cs concentration at two different depth (0 cm -20 cm and 20 cm - 40cm) were measured [Sajó-Bohus et al., 1999]. In Argentina 137Cs reference activity profile was determined in the Pampa Ondulada region [Bujan et al., 2000, 2003] and in the central part of the country in natural and semi-natural grassland regions [Juri Ayub et al., 2007, 2008]. Beside the natural chains values, the profiles of 137Cs in the same region of Buenos Aires Province have been settled [Montes et al. 2010a, 2010b]. Important differences were found, attributed to chemical, physical, mineralogical, edaphic, rainfall rate and climatic factors. References Antonopoulus-Domis, M.; Clouvas, A.; Hiladakis, A. & Kadi, S. (1995). Radiocesium distribution in undisturbed soil: Measurements and diffusion-advection model. Health Physics, Vol.69, pp. 949-953 Bellenber, J. P. & Stauton, S. (2008). Adsorption and desorption of 85Sr and 137Cs on reference minerals, with and without inorganic and organic surface coatings. Journal of Environmental Radioactivity, Vol. 99, pp. 831?840, ISSN 0265 931X Bossen, P. & Kirchner, G. (2004). Modeling the vertical distribution of radionuclides in soils. Part I: the convection-dispersion equation revisited. Journal of Environmental Radioactivity, Vol. 73, pp. 127-150, ISSN 0265 931X Bujan, A.; Santanatoglia, O. J.; Chagas, C.; Massobrio, M.; Castiglioni, M.; Yañez, M.; Ciallella, H. & Fernandez, J. (2000). Preliminary study on the use of the 137Cs method for soil erosion investigation in the pampean region of Argentina. Acta Geologica Hispanica, Vol. 35, pp. 271-277, ISSN 1695 6133 Bujan, A.; Santanatoglia, O. J.; Chagas, C.; Massobrio, M.; Castiglioni, M.; Yañez, M.; Ciallella, H. & Fernandez, J. (2003). Soil erosion evaluation in a small basing though the use of 137Cs technique. Soil & Tillage Research, Vol. 69, pp. 127?137, ISSN 0167 1987 Catallette, H.; Dumonceau, J. & Ollar, P. (1998). Sorption of cesium, barium and europium on magnetite. Journal of Contaminant Hydrology, Vol. 35, pp. 151-159, ISNN 0169- 7722 Cooper, J. R.; Randle & K.; Sokhi, R. S. (2003). In: Radioactive Releases in the Environment, John Wiley & Sons Ltd. ISBN 0 471 89924 0, The Atrium, Southern Gate, Chichester, West Sussex, England Cornell, R. M. (1993). Adsorption of cesium on minerals: a review. Journal of Radioanalytical and Nuclear Chemistry, Vol. 171, pp. 483 ? 500. ISNN 0236 5731 Correchel, V.; Oliveira Santos Bacchi, O.; Reichardt, K. & Cereci de Maria I. (2005). Random and systematic spatial variability of 137Cs inventories at references sites in southcentral Brazil. Scientia Agricola, Vol. 62, pp. 173-178, ISSN 0103 9016 Handl, J.; Sachase, R.; Jakob, D.; Michel, R.; Evangelista, H.; Gonçalves, A. C. & de Freitas, A. C. (2008). Accumulation of 137Cs in Brazilian soils and its transfer to plants under different climatic conditions. Journal of Environmental Radioactivity, Vol. 99, pp. 271- 287, ISSN 0265 931X IAEA. (2010). Handbook of Parameter Values For The Prediction Of Radionuclide Transfer In Terrestrial And Freshwater Environments. Technical Reports Series No. 472, Vienna. Imbellone, P. A.; Guichon, B. A. & Giménez, J. E. (2009). Hydromorphic soils of the River Plate coastal plain, Argentina. Latin american Journal of sedimentology and basin analysis, Vol. 16, pp. 3-18, ISNN 1669-73616 Juri Ayub, J.; Rizzotto, M.; Toso, J. & Velasco, H. (2007). 137Cs deposition and vertical migration in soils from Argentina. Proc. International. Conf. on Environ. Radioctivity: From Measurements and Assessments to Regulation, Vienna, Austria, www-pub.iaea.org/mtcd/meetings/announcements.asp?confid=145 Juri Ayub, J.; Velasco, R.H.; Rizzotto, M.; Quintana E. & Aguiar J. (2008). 40K, 137Cs and 226Ra soil and plant content in semi-natural grasslands of Central Argentina. The Natural Radiation Environment?8th International Symposium, edited by A. S. Paschoa, American Institute of Physics, ISBN 978 0 7354 0559 Kirchner, G. (1998). Applicability of compartmental models for simulating the transport of radionuclides in soil. Journal of Environmental Radioactivity, Vol. 38, pp. 339-352, ISSN 0265 931X Kirchner, G.; Strebl, F.; Bossew, P.; Ehlken, S. & Gerzabek, H. (2009). Vertical migration of radionuclides in undisturbed grassland soils. Journal of Environmental Radioactivity, Vol. 100, pp. 716-720, ISSN 0265 931X Malanca, A.; Gaidolfi, L.; Pessina, V.& Dallara G. (1996). Distribution of 226Ra, 232Th, and 40K in soils of Rio Grande do Norte (Brazil). Journal of Environmental Radioactivity, Vol. 30, pp. 55-67, ISSN 0265 931X Marmier, N. & Fromage, F. (2000). Sorption of Cs(I) on Magnetite in the Presence of Silicates. Journal of Colloid and Interface Sciencie, Vol. 223, pp. 83-88 Montes, M. L.; Taylor, M. A.; Mercader, R. C.; Sives, F. R. & Desimoni, J. (2010a). Hyperfine and radiological characterization of soils of the province of Buenos Aires. Argentina. Journal of Physics: Conference Series, Vol. 217, pp. 012058 012062, ISSN 1742 6596 Montes, M. L.; Mercader, R. C.; Taylor, M. A.; Runco, J.; Ibellone, P.A.; Rivas, P. C. & Desimoni, J. (2010b). Radiological and Hyperfine Characterization of soils from the Northeastern region of the Province of Buenos Aires, Argentina. Hyperfine Interactions. Submitted, ISSN 0304 3834 Montes, M. L. (2011). Private communication Odino Moure, M. R. (2010). Environmental Radioactivity Monitoring Plan in Uruguay. Technical Meeting on in-situ methods for characterization of contaminated sites. Vienna, Austria. http://www-pub.iaea.org/mtcd/meetings/Announcements.asp?ConfID=38924 Sajó-Bohus, L.; Pálfalvi, J.; Urbani, F.; Castro, D.; Greaves, E.D.& Liendo, J.A. (1999). Environmental gamma and radon dosimetry in Venezuela. Radiation Measurements, Vol. 31, pp. 283-286, ISSN 1350 4487 Salbu, B. (2009). Fractionation of radionuclide species in the environment. Journal of Environmental Radioactivity, Vol. 100, pp. 283-289, ISSN 0265 931X Sawhney, B. L. (1972). Selective sorption and fixation of cations by clay minerals: A review. Clays and Clay Minerals, Vol. 20, pp. 93-100, ISSN 0009-8604 Schuller, P.; Ellies, A. & Kirchner, G. (1997). Vertical migration of fallout 137Cs in agricultural soils from southern Chile. Science of the Total Environment, Vol. 193, pp. 197?205, ISSN: 0048 9697 Schuller, P.; Voigt, G.; Handl, J.; Ellies, A. & Oliva, L. (2002). Global weapons fallout 137Cs in soils and transfer to vegetation in south-central Chile. Journal of Environmental Radioactivity, Vol. 62, pp. 181-193, ISSN 0265 931X Schuller, P.; Bunzl, K.; Voigt, G.; Ellies, A. & Castillo, A. (2004). Global fallout 137 Cs accumulation and vertical migration in selected soils from south Patagonia, Journal of Environmental Radioactivity, Vol. 71, pp. 43-60, ISSN 0265 931X Singh, B. K.; Jain, A.; Kumar, S.; Tomar, B. S.; Tomar, R.; Manchanda, V. K. & Ramanathan, S. (2009). Role of magnetite and humic acid in radionuclide migration in the environment, Journal of Contaminant Hydrology, Vol. 106, pp. 144-149. ISNN 0169- 7722 Staunton, S.; Dumat, C.; & Zsolnay, A. (2002). Possible role of organic matter in radiocaesium adsorption in soils. Journal of Environmental Radioactivity, Vol. 58, pp. 163-173, ISSN 0265 931X Tomazini da Conceic, F. & Bonotto, D.M. (2006). Radionuclides, heavy metals and fluorine incidence at Tapira phosphate rocks, Brazil, and their industrial products. Environmental Pollution, Vol. 139, pp. 232-243, ISSN 0269-7491 Toso, J. P. &Velasco, R.H. (2001). Describing the observed vertical transport of radiocesium in specific soils with three time-dependent models. Journal of Environmental Radioactivity, Vol. 53, pp. 133-144, ISSN 0265 931X UNSCEAR, (1982). In: Ionizing Radiation: Sources and Biological effects, Report of the General Assembly with Scientific Annexes, Vol. 1, Annex E, New York, UNSCEAR, (2000). In: Sources and effects of ionizing radiation, Report of the General Assembly with Scientific Annexes, Vol. 1, New York UNSCEAR, (2008). In: Sources and effects of ionizing radiation, Report of the General Assembly with Scientific Annexes, Vol. 1, New York Valdés, M. E.; Blanco, M. V.; Taylor, M. A.; Sives, F.R.;Runco, J. & Desimoni J. (2011). Determinación de las actividades de 60Co, 137Cs y 235U en muestras de suelo, sedimentos y agua provenientes de la zona aledaña a una instalación nuclear. Ciencia Forense Latinoamericana, in press. Vandenberghe, R. E. (1991). In: Mössbauer Spectroscopy and Applications in Geology, International Training Centre for Post-graduate soil Scientists, Geological Institute, Faculteit der Wetenschappen, Faculty of Science, Belgium. Velasco, H. R.; Jury. Ayub, J.; Belli, M.; & Sansone, U. 2006. Interaction matrices as a first step toward a general model of radionuclide cycling: Application to the 137Cs behaviour in a grassland ecosystem. Journal of Radioanalytical and Nuclear Chemistry, Vol. 268, pp. 503-509. ISSN 0236 5731 Valkovic, V. (2000). In: Radioactivity in the Environment, Elsevier, ISBN-13: 9780444829542.