Radon transport phenomena studied in Karst caves-international experiences on radon levels and exposures

Hakl, J.; Hunyadi, I.; Csige, I.; Géczy, G.; Lénárt, László; Várhegyi, A.

doi:10.1016/s1350-4487(97)00163-7

Cited by 72 publications

(41 citation statements)

References 9 publications

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“…There is growing recognition that dripwaters often derive from an epikarstic reservoir of year-round constant PCO 2 (Atkinson, 1977;Fairchild et al, 2000;Spötl et al, 2005), but that cave air shows seasonal changes in PCO 2 (Figure 15). These changes are likely to be caused by combinations of enhanced winter air circulation (as indicated for example by radon studies, Hakl et al, 1997), seasonal changes in PCO 2 of inflowing stream water (Troester and White, 1984), or a seasonal filling of air fissures by water, cutting off the CO 2 supply. These issues are discussed further in Fairchild et al (in press a).…”

Section: Cave Airmentioning

confidence: 99%

Modification and preservation of environmental signals in speleothems

Fairchild

Smith

Baker

et al. 2006

Earth-Science Reviews

736

506

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Speleothems are primarily studied in order to generate archives of climatic change and results have led to significant advances in identifying and dating major shifts in the climate system. However, the climatological meaning of many speleothem records cannot be interpreted unequivocally; this is particularly so for more subtle shifts and shorter time periods, but the use of multiple proxies and improving understanding of formation mechanisms offers a clear way forward.An explicit description of speleothem records as time series draws attention to the nature and importance of the signal filtering processes by which the weather, the seasons and longer-term climatic and other environmental fluctuations become encoded in speleothems. We distinguish five sources of variation that influence speleothem geochemistry: atmospheric, vegetation/soil, karstic aquifer, primary speleothem crystal growth and secondary alteration and give specific examples of their influence. The direct role of climate diminishes progressively through these five factors.We identify and review a number of processes identified in recent and current work that bear significantly on the conventional interpretation of speleothem records, for example: 1) speleothem geochemistry can vary seasonally and hence a research need is to establish the proportion of growth attributable to different seasons and whether this varies over time.2) whereas there has traditionally been a focus on monthly mean δ 18 O data of atmospheric moisture, current work emphasizes the importance of understanding the synoptic processes that lead to characteristic isotope signals, since changing relative abundance of different weather types might 1 Corresponding author, fax +44(0)1214145528, E-mail: i.j.fairchild@bham.ac.uk control their variation on the longer-term. 3) the ecosystem and soil zone overlying the cave fundamentally imprint the carbon and trace element signals and can show characteristic variations with time. 4) new modelling on aquifer plumbing allows quantification of the effects of aquifer mixing. 5) recent work has emphasized the importance and seasonal variability of CO 2 -degassing leading to calcite precipitation upflow of a depositional site on carbon isotope and trace element composition of speleothems. 6) Although much is known about the chemical partitioning between water and stalagmites, variability in relation to crystal growth mechanisms and kinetics is a research frontier. 7) Aragonite is susceptible to conversion to calcite with major loss of chemical information, but the controls on the rate of this process are obscure.Analytical factors are critical to generate high-resolution speleothem records. A variety of methods of trace element analysis are available, but standardization is a common problem with the most rapid methods. New stable isotope data on Irish stalagmite CC3 compares rapid laser-ablation techniques with the conventional analysis of micromilled powders and ion microprobe methods. A high degree of comparability between techniques ...

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Section: Cave Airmentioning

confidence: 99%

Modification and preservation of environmental signals in speleothems

Fairchild

Smith

Baker

et al. 2006

Earth-Science Reviews

736

506

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“…Radon ( 222 Rn, α-radioactive, half-life t 1/2 = 3.82 days) has often been used as an excellent tracer for air circulation, since it is a noble gas and highly abundant in caves (Cigna, 2003;Cunningham and Larock, 1991;Hakl et al, 1996Hakl et al, , 1997Kies and Massen, 1997;Kowalczk and Froelich, 2010;Perrier et al, 2004;Przylibski, 1999). Its half-life, suitable for the timescales on which cave ventilation takes place, distinguishes 222 Rn from the other two radon isotopes ( 220 Rn and 219 Rn).…”

Section: Introductionmentioning

confidence: 99%

“…Radon concentration in underground cave systems is also characterised by internal mixing of air masses (Perrier and Richon, 2010). In a study of 220 caves around the world, Hakl et al (1997) reported an annual average radon concentration of 2800 Bq m −3 .…”

Section: Introductionmentioning

confidence: 99%

Reasons for large fluctuation of radon and CO<sub>2</sub> levels in a dead-end passage of a karst cave (Postojna Cave, Slovenia)

Gregorič¹,

Vaupotič

Gabrovšek

2013

Nat. Hazards Earth Syst. Sci.

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Abstract. Measurements of radon concentration were performed at three geomorphologically different locations in Postojna Cave, Slovenia. In the part of the cave open to visitors, annual average radon activity concentrations of 3255 ± 1190 Bq m−3 and 2315 ± 1019 Bq m−3 were found at the lowest point (LP) and in the Lepe jame (Beautiful Caves, BC), respectively. A much higher average of 25 020 ± 12 653 Bq m−3 was characteristic of the dead-end passage Pisani rov (Gaily Coloured Corridor, GC), in which CO2 concentration also reached very high values of 4689 ± 294 ppm in summer. Seasonal variations of radon and CO2 levels in the cave are governed by convective airflow, controlled mainly by the temperature difference between the cave and the outside atmosphere. The following additional sources of radon and CO2 were considered: (i) flux of geogas from the Earth's crust through fractured rocks (radon and CO2 source), (ii) clay sediments inside the passage (radon source) and (iii) the soil layer above the cave (radon and CO2 source).

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“…On the other hand, understanding CO 2 distribution and dynamics Angel Fernandez-Cortes, Sergio Sanchez-Moral, Soledad Cuezva, Juan Carlos Cañaveras, Rafael Abella in caves is important for palaeoclimate research using stalagmites because their growth rates partially depend on cave atmosphere pCO 2 (Spötl et al, 2005;Fairchild & McMillan, 2007;Baldini et al, 2008). Radon in caves is of interest because concentrations may sometimes reach levels hazardous to human health (Hakl et al, 1997;Craven & Smit, 2006). Therefore, radon monitoring is essential for providing the managers of show caves with some instruments to comply with the domestic legal requirements and to establish the suitable regime of visits.…”

mentioning

confidence: 99%

Annual and transient signatures of gas exchange and transport in the Castañar de Ibor cave (Spain)

Fernández-Cortés¹,

Sánchez‐Moral²,

Cuezva³

et al. 2009

IJS

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Radon transport phenomena studied in Karst caves-international experiences on radon levels and exposures

Cited by 72 publications

References 9 publications

Modification and preservation of environmental signals in speleothems

Modification and preservation of environmental signals in speleothems

Reasons for large fluctuation of radon and CO<sub>2</sub> levels in a dead-end passage of a karst cave (Postojna Cave, Slovenia)

Annual and transient signatures of gas exchange and transport in the Castañar de Ibor cave (Spain)

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Radon transport phenomena studied in Karst caves-international experiences on radon levels and exposures

Cited by 72 publications

References 9 publications

Modification and preservation of environmental signals in speleothems

Modification and preservation of environmental signals in speleothems

Reasons for large fluctuation of radon and CO&lt;sub&gt;2&lt;/sub&gt; levels in a dead-end passage of a karst cave (Postojna Cave, Slovenia)

Annual and transient signatures of gas exchange and transport in the Castañar de Ibor cave (Spain)

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Reasons for large fluctuation of radon and CO<sub>2</sub> levels in a dead-end passage of a karst cave (Postojna Cave, Slovenia)