Dissolved uranium, radium and radon evolution in the Continental Intercalaire aquifer, Algeria and Tunisia

Natural, dissolved U-238-series radionuclides (U, Ra-226, Rn-222) and activity ratios (A.R.s: U-234/U-238; Ra-228/Ra-226) in Continental Intercalaire (Cl) groundwaters and limited samples from the overlying Complexe Terminal (CT) aquifers of Algeria and Tunisia are discussed alongside core measurements for U/Th (and K) in the contexts of radiological water quality, geochemical controls in the aquifer, and water residence times. A redox barrier is characterised downgradient in the Algerian Cl for which a trend of increasing U-234/U-238 A.R.s with decreasing U-contents due to recoil-dominated U-234 solution under reducing conditions allows residence time modelling similar to 500 ka for the highest enhanced A.R. = 3.17. Geochemical modelling therefore identifies waters towards the centre of the Grand Erg Oriental basin as palaeowaters in line with reported C-14 and Cl-36 ages. A similar U-234/U-238 trend is evidenced in a few of the Tunisian CI waters. The paleoage status of these waters is affirmed by both noble gas recharge temperatures and simple modelling of dissolved, radiogenic He-4-contents both for sampled Algerian and Tunisian CI and CT waters. For the regions studied these waters therefore should be regarded as "fossil" waters and treated effectively as a non-renewable resource. (C) 2014 The Authors. Published by Elsevier Ltd.

Towards a Brazilian radon map: consortium radon Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Thoron and radon activity concentration in mineral waters of spas from southeastern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Natural radionuclides in major aquifer systems of the Parana sedimentary basin, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Geo(anthropo)genic factors affecting the radioactivity in groundwaters from Guarani aquifer, Brazil

This investigation was carried out within the Paraná sedimentary basin, involved the sampling of 77 pumped tubular wells, and was realized with the puipose of evaluating the radioactivity in the Brazilian part of Guarani (Botucatu-Pirambóia, Tacuarembó, Misiones) aquifer. The radioactivity due to nuclides belonging to uranium and thorium series decay was investigated in terms of the uranium isotopes 234U and 238U, radon (222Rn), and the radium isotopes 226Ra and 228Ra. The obtained results were compared with the maximum permissible concentration limits in drinking water defined by the Brazilian national standard, as well with the guidelines for drinking water quality established by the World Health Organization. The importance of water-rock/soil interactions was considered in order to explain most of the obtained data.

Uso do Rad7 para a caracterização do torônio em águas de estâncias hidrominerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização radiométrica e de exalação de Radônio em rochas ornamentais silicáticas beneficiadas no Estado do Espírito Santo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

O 222Rn em área contaminada por hidrocarbonetos na região de Santa Bárbara D'Oeste (SP)

Pós-graduação em Geologia Regional - IGCE

Estudo hidroquímico e radiométrico do aquífero Bauru em São José do Rio Preto (SP)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Emanação de radônio em rochas ornamentais e para revestimento do estado do Ceará, Brasil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Rn-222, Ra-226 and hydrochemistry in the Bauru Aquifer System, Sao Jose do Rio Preto (SP), Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Rn-222, Rn-220 and other dissolved gases in mineral waters of southeast Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Radônio como indicador de contaminação de solos por hidrocarbonetos

Previous studies show that in areas contaminated by fuel spill (NAPL- non-aqueous phase liquids), from operational activities, transport and storage, it was possible to observe a significant decrease of ²²²Rn (radon) gas concentration in the soil, even a non-uniform distribution of this gas in top soil, even with a geological situation was practically homogeneous. These anomalies may be associated with the preference partitioning of radon in NAPLs. This work consists of applying ²²²Rn as an indicator for locating subsurface contamination by NAPLs in an area of the city of Rio Claro (SP) where, according to the “Survey of Contaminated and Rehabilitated Areas in the State of São Paulo (Environmental Sanitation and Technology Company - CETESB), there was, in the year 2007, groundwater contamination from leaks of liquid fuels. The challenges of this research are: Promulgate the use of a new tool with greater efficiency in obtaining results, in addition to generate less impact in half and have less expenditure; disseminate scientific culture promoting greater integration of C&T (culture & technology) between universities and businesses. The emanometric technique to estimate the location, number and interfacial area of NAPL in saturated and non-saturated zone, has the advantage of locating and determining plumes of free phase even when the amount of VOC's (Volatile Organic Compounds) that reaches the surface is low or non-existent. In addition, the measurement techniques ²²²Rn are quite developed. The results obtained show that, similar to the other studies, the 222Rn soil gas presents an anomalous behavior in the area bounded by NAPL plume, being possible to note a significant deficit in the concentration of the gas in spots where the saturation by NAPLs is still critical. Therefore it is concluded that this tool is really promising, but we must be careful to evaluate the initial conditions of the area, as well as the type of...

Dosimetria ambiental do gás 222Rn: um exemplo de estudo das águas da região de Presidente Prudente – SP e considerações sobre abordagem do tema através do Banco Internacional de Objetos Educacionais – BIOE

Over the years, the concern with the detection of the levels of radionuclides in the environment has increased, given that they are carcinogenic to the human respiratory system. Present in the air, waters, soil and building materials, among other substances, radionuclides are unknown by most of the population. In this paper, we present the radioactive gas 222Rn, predominant element among all others and one way of detecting it in an example study of the waters of the Presidente Prudente - SP, through the plastic detector called CR-39. Likewise, we realized the need to approach this issue more broadly in schools and even in higher education, since this field of modern physics and environmental physics usually appears only in master's and doctorate. Thus, we attempted to perform the didactic transposition schooluniversity, through the construction of an object Educational, OE, to be placed on the Bank for International Educational Objects - bioethanol and by developing this contribute to the knowledge and understanding of the importance of monitoring of radioactivity in a way accessible to the population as a whole

Determinação de chumbo por análise voltamétrica de pulso diferencial por redissolução anódica em regiões de falhas geológicas com emissão de radônio e filhos de radônio no município de Presidente Prudente

Pós-graduação em Química - IBILCE