Temporal and spatial changes of radon concentration in borehole water (Little Carpathians Mts., Slovakia)
Abstract. The 222Rn activity concentration in ground water from four boreholes was investigated from January 2006 to June 2008. The boreholes are situated in the region of the Astronomical and Geophysical Observatory in Modra-Piesok (Little Carpathians Mts., 40 km NW from Bratislava, Slovakia). Three boreholes have been drilled in Lower Triassic quartzite. Another borehole has been drilled in granodiorite of the Modra massif in which the quartzite is folded. Temporal and spatial differences in radon concentration were observed. Significant short-term variations were noticed in all boreholes. Precipitation caused the changes of water level and strongly affected the values of 222Rn activity concentration in less deep boreholes. The measured activities in boreholes ranged approximately over 1–240 kBq/m3.