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Abstract: Research on earthquake-related radon monitoring has received enormous attention recently. Anomalous behaviour of radon in soil and groundwater can be used as a reliable precursor for an impending earthquake. While earthquake prediction may not yet be possible, earthquake prediction research has greatly increased our understanding of earthquake source mechanisms, the structural complexities of fault zones, and the earthquake recurrence interval, expected at a given location. This paper presents some results of continuous monitoring of radon in soil-gas in Garhwal Himalaya, India. Daily soil-gas radon monitoring with seismic activity and meteorological parameters were performed in the same laboratory system, located at H.N.B. Garhwal University Campus, Tehri Garhwal, India. Radon anomalies along with meteorological parameters were found to be statistically significant for the seismic events within the magnitudes M2.0-M6.0 and epicentral distances of 16–250km from the monitoring station. The frequent positive and negative anomalies with constant environmental perturbation indicate the opening and closing of micro cracks within the volume of dilatancy by strain energy. The spike-like and sharp peak anomalies were recorded before, during and after earthquakes occurred in the area. The variations in radon concentrations in soil-gas are found to be correlated with seismic activities in the Garhwal Himalaya. The correlation between radon level and meteorological parameters is also discussed. [Copyright &y& Elsevier]

Monitoring of radon, thoron and their daughter products was carried out in houses of Kumaun Himalaya, India using LR-115 plastic track detectors. The measurements were made in residential houses from June 1999 to May 2000 at a height of 2.5 m from ground level using a twin chamber radon dosimeter. The twin chamber radon dosimeter can record the values of radon, thoron and their decay products separately. Maximum and minimum indoor radon and thoron concentrations were evaluated and activity concentrations of radon and thoron daughters were estimated. The resulting dose rates due to radon, thoron and their decay products varied from 0.04 to 1.89 μSv/h. A detailed analysis of the distribution of radon, thoron and their decay products inside the house is also reported. The observed dose rates inside the houses of Kumaun Himalaya were found to be lower than the ICRP recommended value of 200 Bq/m3 and thus are within safe limits. [Copyright &y& Elsevier]

Abstract: Levels of radon, thoron, and their progeny were measured in the houses of Garhwal and Kumaun Himalaya using LR-115 plastic track detectors. Radon and thoron concentrations were found to vary from 7 to 191 Bq/m3, and from 1 to 145 Bq/m3, respectively. The equilibrium factor between radon and progeny varies from 0.02 to 0.90, with an average of 0.26 for the region. The resulting dose rate due to radon, thoron, and their decay products varied from 0.04 to 1.89 μSv/h with an average of 0.96 μSv/h. In comparison to the international recommendations, the observed dose rates due to radon, thoron and progeny was found somewhat higher but well below the international recommendations. [Copyright &y& Elsevier]

The radon content in water may serve as a useful tracer for several geohydrological processes. The hydrodynamic factor, presence of radium in host rocks, as well as the soil porosity and permeability control its concentration in groundwater. In order to understand the factors that control the occurrence of radon in groundwater of Doon valley in Outer Himalaya, a total of 34 groundwater samples were collected from handpumps and tubewells covering three hydrogeological units/areas in the eastern part of Doon valley. Radon variation in tubewells and handpumps varies from 25.4±1.8 to 92.5±3.4 Bq/l with an average of 53.5±2.6 Bq/l. A significant positive correlation between radon concentration and depth of the wells was observed in the Doiwala–Dudhli and Jolleygrant areas suggesting that radon concentration increases with drilling depth in areas consisting of sediments of younger Doon gravels, whereas samples of the Ganga catchment show negative correlation. The high radon levels at shallower depths in the Ganga catchment (consisting of fluvial terraces of Ganga basin) indicate uranium-rich sediments at shallower depth. [Copyright &y& Elsevier]

Abstract: The radon content in groundwater sources depends on the radium concentration in the rock of the aquifer. Radon was measured in water in many parts of the world, mostly for the risk assessment due to consumption of drinking water. The exposure to radon through drinking water is largely by inhalation and ingestion. Airborne radon can be released during normal household activities and can pose a greater potential health risk than radon ingested with water. Transport of radon through soil and bedrock by water depends mainly on the percolation of water through the pores and along fractured planes of bedrock. In this study, radon concentration in springs and hand pumps of Kumaun and Garhwal Himalaya, India was measured using radon emanometry technique. The study shows that radon concentration in springs and hand pumps is controlled by geohydrological characteristics, which in turn is also governed by tectonic processes. [Copyright &y& Elsevier]