Radon, radon progeny and unattached radon progeny were measured in two chambers with differentcharacteristics at the Jenolan Caves, New South Wales, Australia, in 1996. Meteorological parametersand condensation nucleus concentrations were measured in order to understand the processesgoverning the radon concentration and degree of disequilibrium with the progeny. One chamber waspoorly ventilated, and rainfall proved to be the most important influence on radon concentration.
In Poland as in many other countries regulations limiting permissible level of radon concentrations indoors are in force. It implies a need for a methodology of searching for houses with elevated radon concentration. Since it was discovered that the bedrock was the most powerful source of radon indoors it has been observed by many researchers that homes with enhanced radon concentrations occur more frequently in particular areas.
A nation-wide survey of radon concentrations in Norwegian dwellings was undertaken in the period 1987 - 89. In this survey, radon measurements were made by CR-39 etched track detectors (six months integration time) in the main bedroom of approximately 7500 randomly selected dwellings built before 1980. The annual average radon concentration in Norwegian bedrooms was calculated to 51 Bq/m3, and 3.7 % of the results exceeded 200 Bq/m3.
The International Commission on Radiological Protection (ICRP) and The Council of the European Union has recommended the Member States to take action against radon in homes and at workplaces. In the ERRICCA project the Group on Legal and Building Code Impact was designated to study the current radon legislation and to give advice on future conduct of laws and recommendations. On behalf of the Group a questionnaire on radon-legislation have been send out to all European States and a selection of non-European States.
The effect of indoor gamma dose rate, permeability of soil, substructure, and ventilation habits of inhabitants were studied using data of 84 low rise residential houses collected in an area of enhanced indoor radon concentration. The radon concentrations varied from 30 to more than 5000 Bqm-3. Cross-tabulation, comparisons of means and multiplicative models were used to test the significance of the effects. In this study a quite high percentage of explained variation R2 - 68% - was found. It was found that the most important factors were the substructure and the permeability of the soil.
In Kinsarvik, Norway, extraordinary high radon levels in dwelling units are revealed. The bedrock geology was expected to give the answer to why the levels are so high. However, the uranium or radium content is not especially high123. Thus, we believe the explanation to the high radon consentration to be related to the unconsolidated sediments4.
In Hungary and Slovenia a lot of thermal water occurrences providing mineral water for spas are used for curative therapeutic purposes in cases of locomotor and gastrointestinal diseases. In these balneotherapeutic facilities the atmosphere can contain radon and radon daughters at high concentrations. Radon diffusing from the pores and cracks of the minerals being dissolved in underground waters is taken up by spa wells and in the spas the radon emanates from the water.
CRR, the Regional Center for Radioactivity, is monitoring Veneto, a region in the north-east of Italy, to trace a map of areas with elevated indoor radon levels. This survey is based on analysis of territorial distribution of radon concentration in dwellings. Maps of potential risk are searched in the upper part of the region based on the indication of a previous survey. Percentage of dwellings exceeding reference levels are estimated on the base of log-normal data distribution. Normalizations to ground floor or average housing type are produced.
Mapping the geogenic radon potential in Germany is a research project initiated by the German Federal Ministry for the Environment, Conservation and Reactor Safety. The project was aimed to develop a standard methodology for the estimation of a geogenic radon potential and to apply this method to map the region of Germany as an overview for planning purposes. The regionalization results from a distance-weighted interpolation of the site-specific values of radon concentration in soil gas and in-situ gas permeability of soils on a regular grid considering the corresponding geological units.
The evaluation of the geogenic radon potential is based on field measurements of radon activity concentration in soil gas. The values obtained through such spot measurements depend strongly on the geological background [1] [2] but also on the soil properties like grainsize distribution, porespace watersaturation and also on meteorological conditions. The goal of this study was to estimate the variability of the radon activity concentration in soil gas and to relate it to the variations of soil properties induced by seasonal changes.
Login