Naslov
Concentration of 222Rn and CO2 in Modrič Cave atmosphere and its implications for the responsible cave management

Autori
Lončarić, Robert ; Surić, Maša ; Radolić, Vanja ; Miklavčić, Igor

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Man and Karst 2022, Book of abstracts / Ruggieri, Rosario - Ragusa : CIRS, Ragusa, 2022, 53-53

Skup
Man and karst

Mjesto i datum
Custonaci, Italija, 12.09.2022. - 17.09.2022

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
karst, caves, carbon dioxide, radon, cave management, Croatia

Sažetak
In karst regions throughout the world caves are considered as a valuable asset in tourism with some of them attracting hundreds of thousands of visitors per year (e.g. Postojna Cave in Slovenia). However, entering the underground comes with certain risks for human health and some of these risks cannot be immediately detected. Carbon dioxide (CO2) and radon (222Rn) regularly occur in caves in concentrations well above those in the atmosphere, and since both gases are considered a health hazard, responsible cave management should include a long-term monitoring of the variations in concentrations of these gases in cave atmosphere to assure safety of both visitors and tour guides. Here we present the results of two monitoring programmes (one finished and one ongoing) of CO2 and 222Rn concentrations in the Modrič Cave (Croatia), a relatively small show cave located at the foothills of the Velebit Mt. near Adriatic coast at 32 m a.s.l. It is a morphologically simple cave with two mainly horizontal passages with total length of 829 m and only one passage (left) is open for public. The results show significant spatial and temporal variations of CO2 and 222Rn. Interestingly, the variations in concentration of both gases follow similar patterns, which suggests that their concentrations are governed by the same mechanisms. The highest concentrations of both gases are recorded in the right passage in summer/autumn season (which coincides with highest number of visitors), and the lowest concentrations are recorded in the left passage during winter/spring season. While the highest recorded concentrations of CO2 of >15, 000 ppm are not considered as a serious threat to human health, the highest recorded values of 222Rn of >12, 000 Bq/m3 can be hazardous particularly for guides which frequently enter the cave as radon can cause mechanical damage to lung tissue potentially leading to lung cancer. Apart from long-term seasonal variations, the obtained data showed abrupt short-term increases in concentrations of both gases during autumn/winter period after intensive rains. During these episodes, concentrations of CO2 and 222Rn can be several times higher than usual. If further studies corroborate regular appearance of such events, it could lead to changes in cave management because cave guides could avoid organizing tours during the periods of significant increases in concentrations of both gases and scientists as well could avoid spending longer periods in the cave during such events.

Izvorni jezik
Engleski

Znanstvena područja
Geologija, Interdisciplinarne prirodne znanosti, Geografija

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