Spatial and temporal variations of radon and their applications : a case study on Southern Thailand

Abstract

The main objective of this research was to study the spatial and temporal variation of radon concentration and their applications: a case study in south of Thailand. The temporal variation of radon in soil gas was observed continuously monitoring at a suitable sampling site at Khlong Marui Fault Zones, Phang Nga Province, using solid state nuclear track detector (SSNTD). The radon was monitored based on of a daily average radon concentration that covered a period year between July 1, 2009 and June 30, 2010. The results showed that the radon anomaly related to the observed earthquakes (data collected from ANSS; Advanced National Seismic System, of NCEDC; Northern California Earthquake Data Center) about 67 % of some precursory anomalous peaks can be correlated to the seismic events with M ≥ 4 in order 0-3 days before the event occurred. The spatial variation of radon was applied to assess the health risks of exposure to radon in Namom district, Songkhla province. Investigations of radon and radium concentration in soil were used to estimate the radiological health hazard indices, it was found to exceed the world permissible limit. In addition, radon concentations in well water samples were measured for human comsumption, found that the average radon levels exceed the limit of 11 Bq 1 -' (USEPA, 1999), and some settlements had radon levels higher than 100 Bq I -' (EU Council Dierective, 2013). These values show a significant health risk due to radiation pollution in study area. It is of concern that the results indicate health risks, especially to those consumers who directly use well water with high radon levels.