Indoor radon monitoring in selected buildings in Vydrnik (Vikartovce fault, Slovakia)

To test the relation of indoor radon concentration to fault zone, a survey was conducted in selected buildings in Vydrnik, situated close to the neo-tectonically active Vikartovce fault trace. Monitoring was performed using RamaRn track detectors during a period of 1 year. Annual average of indoor radon ranged from 60 to 940 Bq/m³, with an average of 160 Bq/m³. Seasonal variation of indoor radon concentration was confirmed, with minimum in summer (June-August). The results confirmed that radon concentration in rooms above the cellar was lower than in rooms with the direct contact with subsoil. High indoor radon up to 940 Bq/m³ was detected only in one of monitored houses situated close to the generally E-W trending Vikartovce fault and can be attributed to this fault zone used as pathway for radon migration. Influence of nearby situated NW-SE trending crosscutting fault on radon concentration is probable too. (authors)