Seasonal variation of radon and CO₂ in the Važecká Cave, Slovakia

Abstract

<jats:title>Abstract</jats:title><jats:p>The continuous monitoring of <jats:sup>222</jats:sup>Rn activity concentration, CO<jats:sub>2</jats:sub> concentration, and microclimatologic parameters (internal air temperature and relative humidity) in the Važecká Cave (Northern Slovakia) is being carried out at three monitoring stations, namely, Gallery, Lake Hall, and Entrance Hall. Radon activity concentration and CO<jats:sub>2</jats:sub> concentration exhibited a clear annual variation. The daily average of radon concentration ranged 1300–27 700 Bq/m<jats:sup>3</jats:sup> at the Lake Hall station and 3600–42 200 Bq/m<jats:sup>3</jats:sup> at the Gallery station. Radon reached its maximum in the summer months, from June to September. The annual maximum of CO<jats:sub>2</jats:sub> concentration is registered approximately one month later than radon maximum. The annual variation of radon and CO<jats:sub>2</jats:sub> is controlled by the seasonal change of ventilation regime associated with the seasonal variation of the difference between the temperature measured inside the cave and the atmospheric temperature.</jats:p>

Effects of Anthropogenic Disturbance and Seasonal Variation on Aerobiota in Highly Visited Show Caves in Slovenia

“…Our results are consistent with this, as the field measurements show that CO 2 generally increase slightly during tourist visits, 1.2 times the concentration before tourist visits, similar to the 1974 study by Gams [38]. However, in agreement with other studies [39,40], CO 2 concentrations show a seasonal distribution, being highest in summer and autumn and lowest in winter, and were not as clearly affected by tourists as the aerobiome. BDG also showed a seasonal distribution with the highest concentrations in autumn and the lowest in spring at all sampling sites.…”

Use of Radon and CO2 for the Identification and Analysis of Short-Term Fluctuations in the Ventilation of the Polychrome Room Inside the Altamira Cave

“…It is common to find in literature, cycles of indoor gas accumulation associated with a higher degree of insulation from the external atmosphere during the spring-summer period, followed by cycles of degassing during the autumn-winter period. However, this is not a standard rule, as the distribution of such cycles may vary depending on the morphology of the cave [ 18 , 19 , 20 , 21 , 22 , 23 ].…”

Spatiotemporal Variations of Radon Concentration in the Atmosphere of Zhijindong Cave (China)

“…Compared with some karst tourist caves in China, the radon concentration of Zhijindong Cave is lower than that of Xueyu cave (4271.4 Bq/m 3 ) [22] and is close to that of caves in Lantian [15]. Compared with some other karst tourist caves in the world, the radon concentration in Zhijindong Cave is higher than caves in Romania [33], lower than the Važecká cave (1300-42,200 Bq/m 3 ) and the Altamira cave (3562 Bq/m 3 ) [11,16]. The temporal variation of radon concentration is closely related to the temperature between the outside atmosphere and the cave atmosphere (Figure 4).…”

“…Radon concentrations can reach hundreds of thousands of Bq/m 3 in some cave environments [8,9]. Although the content of uranium in limestone is low, carbonates are prone to uranium enrichment during weathering [10], which can resulting in higher radon concentrations in caves in many karst regions of the world [11][12][13][14].The concentration of radon in karst cave air depends on the complex interaction of several different factors, including the internal and external temperature difference, the mixing degree of external air and cave air, the internal humidity of the cave, precipitation and its infiltration into the cave environment, the content of 226 Ra in rock strata and cave sediments, the porosity of rock and cave sediments, and the volume and shape of the cave [15,16]. Among them, the cave ventilation caused by meteorological conditions is considered to be the biggest influencing factor [9].…”