Radon concentrations and exposure levels in Hungarian caves

Area of Science:

• Environmental Science
• Public Health
• Radiological Protection

Background:

• Underground workers, including those in mines and caves, face potential exposure to radon (222Rn) and its progeny.
• Cave environments, particularly those utilized for speleotherapy or tourism, require assessment for indoor radon levels.

Purpose of the Study:

• To measure radon and radon progeny concentrations in four Hungarian caves.
• To evaluate seasonal variations in radon levels within these cave systems.
• To calculate radiation doses for cave staff, patients, and visitors and compare them to established safety limits.

Main Methods:

• Radon and radon progeny concentrations were measured in four distinct Hungarian caves.
• Seasonal variations in radon levels were monitored.
• Calculations were performed for cumulative Working Level Month (WLM) exposures, bronchial dose, and effective dose equivalent.

Main Results:

• All investigated caves exhibited seasonal radon variations, with higher levels in summer and lower levels in winter.
• Non-regular diurnal radon variations were noted in caves with less isolated indoor air.
• Effective dose equivalent values for cave personnel were below the 20 mSv y-1 limit.
• Doses for visitors and patients were significantly lower than for personnel.

Conclusions:

• Radon exposure in the studied Hungarian caves, including speleotherapy sites, poses no significant health risk to staff, patients, or visitors.
• Cave environments demonstrate predictable seasonal radon fluctuations and some diurnal variations influenced by air exchange.
• Radiation protection measures are effective, as calculated doses remain within acceptable occupational and public exposure guidelines.