Indoor radon measurements and methodologies in Latin American countries

According to the current international guidelines concerning environmental problems, it is necessary to evaluate and to know the indoor radon levels, specially since most of the natural radiation dose to man comes from radon gas and its progeny. Several countries have established National Institutions and National Programs for the study of radon and its connection with lung cancer risk and public health. The aim of this work is to present the indoor radon measurements and the detection methods used for different regions of Latin America (LA) in countries such as Argentina, Brazil, Ecuador, Mexico, Peru and Venezuela. This study shows that the passive radon devices based on alpha particle nuclear track methodology (NTM) is one of the more generalized methods in LA for long term indoor radon measurements, CR-39, LR-115 and Makrofol being the more commonly used detector materials. The participating institutions and the radon level measurements in the different countries are presented in this contribution. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Indoor radon measurements in six Latin American countries

Most of the natural radiation dose to man comes from radon gas and its progeny. Several countries have established national institutions and national programs in charge of the study of radon and its connection with lung cancer risk and public health. In this paper an indoor radon measurements in Latin American countries is presented. The participants in this work were from Argentina, Brazil, Ecuador, Mexico, Peru and Venezuela. Many different techniques are used in this common effort, and the indoor radon levels in specific locations in each of the participant countries are presented.

Effects of environrnental conditions on the radon daughters spatial distribution

The influence of environmental conditions on the indoor radon daughters spatial distribution is studied both theoretically and experimentally. Simple theoretical calculations indicate that ventilation and variation in the size distribution of aerosols should play an important role influencing the spatial distribution of indoor radon decay products, but experimental results indicate that these environmental factors have little influence on the spatial distribution of radon daughters near the walls of indoor environments. We have observed that the maximum effective range of the plate-out effect varies only between I and 3 cm in typical dwellings. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Assessment of effective doses from radon levels for tour guides at several galleries of Santana Cave, Southern Brazil, with CR-39 detectors: preliminary results

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Towards a Brazilian radon map: consortium radon Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Uranium distribution and radon exhalation from Brazilian dimension stones

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Radon surveys in Brazil using CR-39

In this work results of two radon daughters survey in Brazil are presented and discussed. Some methodological problems concerning the first survey are pointed out which were corrected for the second survey in order to make a realistic long-term measurement of radon decay products in the air. The technique employed in both surveys was the alpha-spectroscopy using CR-39. The reliability of this technique as well as the results of the second survey are discussed, which indicate a poor correlation between radon and its decay products in the air at the researched dwellings. (c) 2005 Elsevier Ltd. All rights reserved.

Indoor Air quality related to occupancy at an air-conditioned public building

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

Energy system contributions in indoor rock climbing

The present study cross-sectionally investigated the influence of training status, route difficulty and upper body aerobic and anaerobic performance of climbers on the energetics of indoor rock climbing. Six elite climbers (EC) and seven recreational climbers ( RC) were submitted to the following laboratory tests: ( a) anthropometry, (b) upper body aerobic power, and ( c) upper body Wingate test. on another occasion, EC subjects climbed an easy, a moderate, and a difficult route, whereas RC subjects climbed only the easy route. The fractions of the aerobic (WAER), anaerobic alactic (W-PCR) and anaerobic lactic (W-[La(])-) systems were calculated based on oxygen uptake, the fast component of excess post-exercise oxygen uptake, and changes in net blood lactate, respectively. on the easy route, the metabolic cost was significantly lower in EC [ 40.3 ( 6.5) kJ] than in RC [60.1 ( 8.8) kJ] ( P < 0.05). The respective contributions of the WAER, WPCR, and W-[La(])- systems in EC were: easy route = 41.5 (8.1), 41.1 (11.4) and 17.4% (5.4), moderate route = 45.8 (8.4), 34.6 (7.1) and 21.9% (6.3), and difficult route = 41.9 (7.4), 35.8 (6.7) and 22.3% (7.2). The contributions of the WAER, WPCR, and W-[La(])- systems in RC subjects climbing an easy route were 39.7 (5.0), 34.0 (5.8), and 26.3% (3.8), respectively. These results indicate that the main energy systems required during indoor rock climbing are the aerobic and anaerobic alactic systems. In addition, climbing economy seems to be more important for the performance of these athletes than improved energy metabolism.

Radon in groundwaters from Guarany aquifer, South America: environmental and exploration implications

Groundwater and sandstone samples were analyzed for radon in Guarany aquifer, Parana sedimentary basin, South America. The dissolved radon ranged between 3 and 3303 pCi/l, being lognormally distributed, with a modal value of 1315 pCi/l, and a median value of 330 pCi/l. Rn-222 leakage experiments for sandstones yielded a theoretical value of 1390 pCi/l for Rn-222 in water, showing that theoretical modeling can reliably be used to interpret laboratory and field data. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

A combined method for evaluating radon and progeny in waters and its use at Guarani aquifer, São Paulo State, Brazil

A combined method for evaluating radon (Rn-222) and progeny (Pb-214 and Bi-214) in water was developed by using inexpensive alpha scintillation Counting and gamma ray spectrometry through NaI(Tl) scintillation detectors. A groundwater sample collected at the Pocos de Caldas alkaline massif in Brazil was submitted to the technique in order to assure its applicability by comparing the volumetric activities by different methods. Similar volumetric activity was determined for Pb-214 and Bi-214 in the sample analyzed that is compatible with the expected condition of radioactive equilibrium between these nuclides. The combined method was successfully used to analyze groundwater samples from Guarani aquifer in S (a) over tildeo Paulo State, Brazil, and the results of the measurements indicated that Pb-214 and Bi-214 provide useful information concerning the evaluation of the drinking water quality in terms of radiological aspects. This is because they are directly identified in the water samples, without the need of requiring the assumption of the establishment of the transient equilibrium condition with its parent Rn-222. (c) 2005 Elsevier Ltd. All rights reserved.

Radon in groundwater contaminated by dissolved hydrocarbons in Santa Barbara d'Oeste, São Paulo State, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Natural radioactivity and radon exhalation rate in Brazilian igneous rocks

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Radon and progeny (Pb-214 and Bi-214) in urban water-supply systems of São Paulo State, Brazil

Many water-supply systems in South America utilize the waters of the Guarani aquifer at least as part of their networks. However, there is little present knowledge in Brazil of the factors affecting Rn presence in the water supplied for end-users, despite the economic importance of Guarani aquifer. Rn-222 analyzes of 162 water samples were performed at 8 municipalities in São Paulo State, Brazil, with the aim of investigating the major factors affecting its presence in solution. The Rn-222 activity concentration ranged from 0.04 up to 204.9 Bq/L, with three samples exceeding the World Health Organization maximum limit of 100Bq/L. Aeration was confirmed as the most important factor for Rn release, as expected due to its gaseous nature. Accumulation in pipes and stratification in the water column were other significant factors explaining the data obtained in some circumstances. The Rn daughters Ph-214 and Bi-214 were also determined in a set of selected samples and their presence was directly related to the occurrence of Rn dissolved in water. (c) 2008 Elsevier Ltd. All rights reserved.

Influence of sugarcane burning on indoor/outdoor PAH air pollution in Brazil

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