Hypogene Caves of Romania

Few caves exist in Romania that have provided clear evidences of their hypogene origin; these were described mainly in connection with investigations conducted on ore deposits or thermal water resources used in spas. Genetically, they are grouped in three categories: (1) caves related to upwelling of H2S-rich thermal waters along Cerna Valley (SW Romania) and around the town of Mangalia (SE Romania), (2) voids created in skarns and limestones during ascending flow of hot metasomatic and hydrothermal ore fluids (caves located mainly in the northern and western part of the country), and (3) mixing of salt and fresh water near the present Black Sea shore (e.g., Piatra Cave). Among all caves in these categories, Movile, a world-renowned biospeleological hot spot, the skarn-hosted caves from Băița, and Valea Rea, an underground mineralogical treasure, are the most representative

Radon Levels in Romanian Caves: An Occupational Exposure Survey

A comprehensive radon survey has been carried out in seven caves located in the western half of Romania’s most significant karst regions. Touristic and non-touristic caves were investigated with the aim to provide a reliable distribution of their radon levels and evaluate the occupational exposure and associated effective doses. Radon gas concentrations were measured with long-term diffusion-type detectors during two consecutive seasons (warm and cold). All investigated caves exceed the European Union reference level of radon gas at workplaces (300 Bq/m3). The radon concentration in these caves ranges between 53 and 2866 Bq/m3, reflecting particular cave topography, season-related cave ventilation, and complex tectonic and geological settings surrounding each location. Relatively homogeneous high radon levels occur in all investigated touristic caves and in Tăuşoare and Vântului along their main galleries. Except for Muierii, in all the other caves radon levels are higher during the warm season, compared to the cold one. This suggests that natural cave ventilation largely controls the underground accumulation of radon. The results reported here reveal that the occupational exposure in Urşilor, Vadu Crişului, Tăuşoare, Vântului, and Muierii caves needs to be carefully monitored. The effective doses to workers vary between an average of 0.25 and 4.39 mSv/year depending on the measuring season. The highest values were recorded in show caves, ranging from 1.15 to 6.15 mSv/year, well above the European recommended limit, thus posing a potential health hazard upon cave guides, cavers, and scientists