MULTI-YEAR MONITORING OF RADON IN BOREHOLES AT THE MODRA GEOPHYSICAL OBSERVATORY, SLOVAKIA

Area of Science:

• Environmental Science
• Geophysics
• Radiological Science

Background:

• Radon (Rn) is a naturally occurring radioactive gas.
• Understanding radon behavior in subsurface environments is crucial for environmental and health assessments.

Purpose of the Study:

• To conduct long-term radon monitoring in two distinct boreholes.
• To analyze diurnal, multi-day, and annual variations in radon concentrations.
• To investigate the influence of meteorological parameters on radon levels.

Main Methods:

• Continuous radon monitoring in V-2 (13m depth, Aug 2003-Sep 2005) and V-3 (3m depth, Aug 2003-Apr 2008) boreholes.
• Time-series analysis of radon activity data.
• Correlation analysis with meteorological data (temperature, atmospheric pressure, rainfall).

Main Results:

• Significant diurnal, multi-day, and annual radon variations were observed in both boreholes.
• V-2 borehole exhibited higher average radon activity (6.5–383.7 kBq/m³) compared to V-3 (1.2–139.4 kBq/m³).
• Seasonal patterns were more pronounced in V-3, coinciding with temperature changes; multi-day variations correlated with atmospheric pressure.
• Increased radon activity in V-3 followed rainfall events during spring and summer.

Conclusions:

• Radon concentrations in boreholes are dynamic and influenced by multiple factors.
• Meteorological parameters, including temperature, atmospheric pressure, and rainfall, play a significant role in modulating radon levels.
• The findings highlight the complex interplay between geological conditions, environmental factors, and radon gas transport.