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Perrier F, Bourges F, Girault F, Lartiges B, Bonnet S, Genty D, Denele Y, Regard V, Régnier É, Bouquerel H, Lei B, Rivet T, Losno R. Radon-222 signatures of atmospheric dynamics in the Pech Merle Painted Cave, France: Consequences for management and conservation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 949:174648. [PMID: 39009146 DOI: 10.1016/j.scitotenv.2024.174648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 06/26/2024] [Accepted: 07/07/2024] [Indexed: 07/17/2024]
Abstract
Radon-222, a radioactive noble gas with a half-life of 3.8 days produced by radium-226, is a health hazard in caves, but also a powerful tracer of atmospheric dynamics. Here we show how airborne radon-222 can be analysed in a cave with multiple openings, the Pech Merle Cave in South-West France. This two-level cave hosts prehistoric remains and Gravettian paintings in its lower level. Radon concentration, monitored at 15 points with one-hour sampling intervals for more than one year, including two points for more than three years, showed mean values from 1274 ± 11 to 5281 ± 20 Bq m-3, with transient values above 15,000 Bq m-3. Seasonal variations were observed, with a weak normal cycle (low in winter) at two points in the upper level and a pronounced inverse seasonal cycle (low in summer) at the other points in the cave. The radon-222 source (effective radium-226 concentration, ECRa) was measured in the laboratory for floor deposits, soil and rock samples. While ECRa values obtained for rocks and speleothems are smaller than 1 Bq kg-1, most ECRa values for soils are larger than 10 Bq kg-1. Quantitative modelling confirms that the floor fillings inside the cave are responsible for the stationary lower concentrations, while the higher concentrations observed in winter are explained by percolation of outside air, which collects radon-222 as it passes through the soil layers. In addition, Stored Available Radon (SAR) is sufficient to account for transient variations. While air currents occur when visitors enter the cave or when the cave is deliberately ventilated, the climatic processes revealed by their radon-222 signatures appear to be essentially natural. These processes, enhanced by global climate change, could cause or accelerate the deterioration of prehistoric paintings. Radon-222 source analysis using ECRa-based modelling and SAR appears essential for the preservation of underground heritage.
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Affiliation(s)
- Frédéric Perrier
- Université Paris Cité, Institut de Physique du Globe de Paris, CNRS, F-75005 Paris, France.
| | - François Bourges
- Géologie Environnement Conseil, 30 rue de la République, F-09200 Saint-Girons, France
| | - Frédéric Girault
- Université Paris Cité, Institut de Physique du Globe de Paris, CNRS, F-75005 Paris, France
| | - Bruno Lartiges
- Géosciences Environnement-Toulouse, Université de Toulouse, IRD, UPS, CNRS (Toulouse), Toulouse, France
| | - Stéphane Bonnet
- Géosciences Environnement-Toulouse, Université de Toulouse, IRD, UPS, CNRS (Toulouse), Toulouse, France
| | - Dominique Genty
- Environnements et Paléoenvironnements Océaniques et Continentaux, Université de Bordeaux, F-33615 Pessac Cedex, France
| | - Yoann Denele
- Géosciences Environnement-Toulouse, Université de Toulouse, IRD, UPS, CNRS (Toulouse), Toulouse, France
| | - Vincent Regard
- Géosciences Environnement-Toulouse, Université de Toulouse, IRD, UPS, CNRS (Toulouse), Toulouse, France
| | - Édouard Régnier
- Laboratoire des Sciences du Climat et de l'Environnement, CNRS, F-91691 Gif-sur-Yvette, France
| | - Hélène Bouquerel
- Université Paris Cité, Institut de Physique du Globe de Paris, CNRS, F-75005 Paris, France
| | - Bo Lei
- Université Paris Cité, Institut de Physique du Globe de Paris, CNRS, F-75005 Paris, France; School of Resource Environment and Safety Engineering, University of South China, Hengyang, Hunan 421001, PR China
| | - Thierry Rivet
- Université Paris Cité, Institut de Physique du Globe de Paris, CNRS, F-75005 Paris, France
| | - Rémi Losno
- Université Paris Cité, Institut de Physique du Globe de Paris, CNRS, F-75005 Paris, France
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Ruiz MC, Pla C, Fernandez-Cortes A, Benavente D. Responses of underground air and drip water geochemistry to meteorological factors: A multi-parameter approach in the Rull Cave (Spain). THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 926:171837. [PMID: 38513849 DOI: 10.1016/j.scitotenv.2024.171837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 02/29/2024] [Accepted: 03/18/2024] [Indexed: 03/23/2024]
Abstract
Our research aims to assess the complex interactions between the elements that constitute and influence a cave system through the analysis of an extensive dataset of climatic and environmental parameters (222Rn, CO2, drip rates, chemical composition, and environmental isotopes) measured in air, water, and solid in the Rull Cave (southeastern Spain). Of particular importance is understanding the effect of rainfall and temperature on water and gas transport through the epikarst and the involved processes. Our results show that the cave gaseous concentration patterns do not only depend on the temperature-caused movement of air masses, but they can also be affected by abundant rainfall. The δ18O and δD composition of cave water also relies on such precipitations for the effective transfer of the rainfall signal into the cave, which can take between 3 and 7 days. The elemental ratios (Sr/Ca and Mg/Ca) show high responsiveness to the water drip rate, hinting that enhanced prior calcite precipitation (PCP) occurs at slower drip rates. Despite this, and regardless of drip rates, calcite saturation indices follow a seasonal variation pattern inversely proportional to the cave air CO2 concentration, while δ13C-DIC is proportional. Our results show how the interlinkage between these multiple components defines the dynamics of the atmosphere-soil-cave system. Cave monitoring is then essential to understand the karstic vadose zone, which is highly sensitive to climatic influence and its changes.
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Affiliation(s)
- M Candela Ruiz
- Department of Earth and Environmental Sciences, University of Alicante, C. San Vicente del Raspeig s/n, 03690 San Vicente del Raspeig, Alicante, Spain.
| | - Concepción Pla
- Department of Civil Engineering, University of Alicante, C. San Vicente del Raspeig s/n, 03690 San Vicente del Raspeig, Alicante, Spain.
| | - Angel Fernandez-Cortes
- Department of Biology and Geology, University of Almeria, C. Sacramento s/n, 04120 La Cañada de San Urbano, Almería, Spain.
| | - David Benavente
- Department of Earth and Environmental Sciences, University of Alicante, C. San Vicente del Raspeig s/n, 03690 San Vicente del Raspeig, Alicante, Spain.
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Sáez M, Benavente D, Cuezva S, Huc M, Fernández-Cortés Á, Mialon A, Kerr Y, Sánchez-Moral S, Mangiarotti S. Scenarios for the Altamira cave CO 2 concentration from 1950 to 2100. Sci Rep 2024; 14:10359. [PMID: 38710702 DOI: 10.1038/s41598-024-60149-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 04/19/2024] [Indexed: 05/08/2024] Open
Abstract
A data-driven approach insensitive to the initial conditions was developed to extract governing equations for the concentration of CO2 in the Altamira cave (Spain) and its two main drivers: the outside temperature and the soil moisture. This model was then reformulated in order to use satellite observations and meteorological predictions, as a forcing. The concentration of CO2 inside the cave was then investigated from 1950 to 2100 under various scenarios. It is found that extreme levels of CO2 were reached during the period 1950-1972 due to the massive affluence of visitors. It is demonstrated that it is possible to monitor the CO2 in the cave in real time using satellite information as an external forcing. For the future, it is shown that the maximum values of CO2 will exceed the levels reached during the 1980s and the 1990s when the CO2 introduced by the touristic visits, although intentionally reduced, still enhanced considerably the micro corrosion of walls and pigments.
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Affiliation(s)
- Marina Sáez
- Université de Toulouse CESBIO (CNES, CNRS, INRAE, IRD, UPS), Toulouse, France
- University of Alicante, Alicante, Spain
| | | | | | - Mireille Huc
- Université de Toulouse CESBIO (CNES, CNRS, INRAE, IRD, UPS), Toulouse, France
| | | | - Arnaud Mialon
- Université de Toulouse CESBIO (CNES, CNRS, INRAE, IRD, UPS), Toulouse, France
| | - Yann Kerr
- Université de Toulouse CESBIO (CNES, CNRS, INRAE, IRD, UPS), Toulouse, France
| | | | - Sylvain Mangiarotti
- Université de Toulouse CESBIO (CNES, CNRS, INRAE, IRD, UPS), Toulouse, France.
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Levintal E, Lee Kang K, Larson L, Winkelman E, Nackley L, Weisbrod N, Selker JS, Udell CJ. eGreenhouse: Robotically positioned, low-cost, open-source CO 2 analyzer and sensor device for greenhouse applications. HARDWAREX 2021; 9:e00193. [PMID: 35492037 PMCID: PMC9041245 DOI: 10.1016/j.ohx.2021.e00193] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/07/2021] [Accepted: 03/18/2021] [Indexed: 05/30/2023]
Abstract
Advances in gas sensors and open-source hardware are enabling new options for low-cost and light-weight gas sampling devices that are also robust and easy to use and construct. Although the number of studies investigating these sensors has been increasing in the last few years, they are still scarce with respect to agricultural applications. Here, we present a complete system for high-accuracy measurements of temperature, relative humidity, luminosity, and CO2 concentrations. The sensors suite is integrated on the previously developed HyperRail device (Lopez Alcala et al., 2019) - a reliable, accurate, and affordable linear motion control system. All measurements are logged with a location and time-stamp. The system was assembled from only off-the-shelf or 3D printable products. We deployed the system in an agricultural greenhouse to demonstrate the system capabilities.
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Affiliation(s)
- Elad Levintal
- Environmental Hydrology and Microbiology, The Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Israel
| | - Kenneth Lee Kang
- Openly Published Environmental Sensing (OPEnS) Lab, Oregon State University, OR, United States
- Department of Electrical Engineering and Computer Science, Oregon State University, OR, United States
| | - Lars Larson
- Openly Published Environmental Sensing (OPEnS) Lab, Oregon State University, OR, United States
| | - Eli Winkelman
- Openly Published Environmental Sensing (OPEnS) Lab, Oregon State University, OR, United States
| | - Lloyd Nackley
- Department of Horticulture, North Willamette Research and Extension Center, Oregon State University, OR, United States
| | - Noam Weisbrod
- Environmental Hydrology and Microbiology, The Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Israel
| | - John S. Selker
- Openly Published Environmental Sensing (OPEnS) Lab, Oregon State University, OR, United States
- Department of Biological & Ecological Engineering, Oregon State University, OR, United States
| | - Chester J. Udell
- Openly Published Environmental Sensing (OPEnS) Lab, Oregon State University, OR, United States
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Levintal E, Dragila MI, Zafrir H, Weisbrod N. The role of atmospheric conditions in CO 2 and radon emissions from an abandoned water well. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 722:137857. [PMID: 32182515 DOI: 10.1016/j.scitotenv.2020.137857] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 02/19/2020] [Accepted: 03/09/2020] [Indexed: 06/10/2023]
Abstract
Boreholes and wells are complex boundary features at the earth-atmosphere interface, connecting the subsurface hydrosphere, lithosphere, and biosphere to the atmosphere above it. It is important to understand and quantify the air exchange rate of these features and, consequently their contribution as sources for greenhouse gas (GHG) emissions to the atmosphere. Here, we investigate the effect of atmospheric conditions, namely atmospheric pressure and temperature, on air, CO2, and radon transport across the borehole-ambient atmosphere interface and inside a 110-m deep by 1-m diameter borehole in northern Israel. Sensors to measure temperature, relative humidity, CO2, and radon were placed throughout a cased borehole. A standard meteorological station was located above the borehole. Data were logged at a high 0.5-min resolution for 9 months. Results show that climatic driving forces initiated 2 different advective air transport mechanisms. (1) Diurnal and semidiurnal atmospheric pressure cycles controlled daily air transport events (barometric pumping); and (2) There was a correlation between borehole-atmosphere temperature differences and transport on a seasonal scale (thermal-induced convection). Barometric pumping was identified as yielding higher fluxes of vadose zone gases than thermal-induced convection. Air velocities inside the borehole and CO2 emissions to the atmosphere were quantified, fluctuating from zero up to ~6 m/min and ~5 g-CO2/min, respectively. This research revealed the mechanisms involved in the process throughout the year and the potential contribution role played by boreholes to GHG emissions.
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Affiliation(s)
- Elad Levintal
- Environmental Hydrology and Microbiology, The Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Israel
| | - Maria I Dragila
- Department of Crop and Soil Science, Oregon State University, USA
| | | | - Noam Weisbrod
- Environmental Hydrology and Microbiology, The Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Israel.
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Bourges F, Genty D, Perrier F, Lartiges B, Régnier É, François A, Leplat J, Touron S, Bousta F, Massault M, Delmotte M, Dumoulin JP, Girault F, Ramonet M, Chauveau C, Rodrigues P. Hydrogeological control on carbon dioxide input into the atmosphere of the Chauvet-Pont d'Arc cave. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 716:136844. [PMID: 32059316 DOI: 10.1016/j.scitotenv.2020.136844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 01/16/2020] [Accepted: 01/20/2020] [Indexed: 06/10/2023]
Abstract
Carbon dioxide (CO2) concentration (CDC) is an essential parameter of underground atmospheres for safety and cave heritage preservation. In the Chauvet cave (South France), a world heritage site hosting unique paintings dated 36,000 years BP, a high-sensitivity monitoring, ongoing since 1997, revealed: 1) two compartments with a spatially uniform CDC, a large volume (A) (40,000 to 80,000 m3) with a mean value of 2.20 ± 0.01% vol. in 2016, and a smaller remote room (B) (2000 m3), with a higher mean value of 3.42 ± 0.01%; 2) large CDC annual variations with peak-to-peak amplitude of 2% and 1.6% in A and B, respectively; 3) long-term changes, with an increase of CDC and of its annual amplitude since 1997, then faster since 2013, reaching a maximum of 4.4% in B in 2017, decreasing afterwards. While a large effect of seasonal ventilation is ruled out, monitoring of seepage at two dripping points indicated that the main control of CDC seasonal reduction was transient infiltration. During periods of water deficit, calculated from surface temperature and rainfall, CDC systematically increased. The carbon isotopic composition of CO2, correlated with water excess, is consistent with a time-varying component of CO2 seeping from above. The CO2 flux, which is the primary driver of CDC in A and B, inferred using box modelling, was found to confirm the relationship between water excess and reduced CO2 flux into A, compatible with a more constant flux into B. A buoyancy-driven horizontal CO2 flow model in the vadose zone, hindered by water infiltration, is proposed. Similarly, pluri-annual and long-term CDC changes can likely be attributed to variations of water excess, but also to increasing vegetation density above the cave. As CDC controls the carbonate geochemistry, an increased variability of CDC raises concern for the preservation of the Chauvet cave paintings.
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Affiliation(s)
- François Bourges
- Géologie Environnement Conseil, 30 rue de la République, F-09200 Saint-Girons, France
| | - Dominique Genty
- Université Paris-Saclay, CEA, CNRS, UVSQ, Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Gif-sur-Yvette, France
| | - Frédéric Perrier
- Institut de Physique du Globe de Paris, Université de Paris, 1 rue Jussieu, F-75005 Paris, France.
| | - Bruno Lartiges
- Université de Toulouse III Paul Sabatier, Géosciences Environnement-Toulouse, 14 av. Edouard Belin, F-31400 Toulouse, France
| | - Édouard Régnier
- Université Paris-Saclay, CEA, CNRS, UVSQ, Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Gif-sur-Yvette, France
| | - Alexandre François
- Laboratoire de Recherches des Monuments Historiques (CRC, USR3224), Museum national d'Histoire naturelle, Sorbonne Universités, Ministère de la Culture, CRNS, 29 rue de Paris, F-77420 Champs-sur-Marne, France
| | - Johann Leplat
- Laboratoire de Recherches des Monuments Historiques (CRC, USR3224), Museum national d'Histoire naturelle, Sorbonne Universités, Ministère de la Culture, CRNS, 29 rue de Paris, F-77420 Champs-sur-Marne, France
| | - Stéphanie Touron
- Laboratoire de Recherches des Monuments Historiques (CRC, USR3224), Museum national d'Histoire naturelle, Sorbonne Universités, Ministère de la Culture, CRNS, 29 rue de Paris, F-77420 Champs-sur-Marne, France
| | - Faisl Bousta
- Laboratoire de Recherches des Monuments Historiques (CRC, USR3224), Museum national d'Histoire naturelle, Sorbonne Universités, Ministère de la Culture, CRNS, 29 rue de Paris, F-77420 Champs-sur-Marne, France
| | - Marc Massault
- Géosciences Paris-Sud (GEOPS), Université de Paris Saclay, Rue du Belvédère Bâtiment 504, 91400 Orsay, France
| | - Marc Delmotte
- Université Paris-Saclay, CEA, CNRS, UVSQ, Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Gif-sur-Yvette, France
| | - Jean-Pascal Dumoulin
- Laboratoire de Mesure du Carbone 14 (LMC14), LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - Frédéric Girault
- Institut de Physique du Globe de Paris, Université de Paris, 1 rue Jussieu, F-75005 Paris, France
| | - Michel Ramonet
- Université Paris-Saclay, CEA, CNRS, UVSQ, Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Gif-sur-Yvette, France
| | - Charles Chauveau
- Service de la Conservation de la Grotte Chauvet, Ministère de la Culture, F-07150 Vallon-Pont-d'Arc, France
| | - Paulo Rodrigues
- Service de la Conservation de la Grotte Chauvet, Ministère de la Culture, F-07150 Vallon-Pont-d'Arc, France
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Guirado E, Ramos-López D, Maldonado A, Moreno-Balcázar J, Calaforra J. Modeling carbon dioxide for show cave conservation. J Nat Conserv 2019. [DOI: 10.1016/j.jnc.2019.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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8
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Joun WT, Rossabi J, Shin WJ, Lee KK. Real-time multi-level CO 2 concentration monitoring in vadose zone wells and the implication for detecting leakage events. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 237:534-544. [PMID: 30825786 DOI: 10.1016/j.jenvman.2019.01.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/08/2019] [Accepted: 01/16/2019] [Indexed: 06/09/2023]
Abstract
Multi-level wells screened at different depths in the vadose zone were installed and used for CO2 and carbon isotope monitoring. Well CO2 time series data were collected along with subsurface and atmospheric parameters such as air pressure, temperature, wind speed, and moisture content. Our aim was to determine the natural factors affecting the variation of CO2 concentration and how the influence of these factors varies with time of day and seasons of the year. We were motivated to understand the cause and extent of CO2 natural fluctuations in vadose zone wells in order to separate natural variation from signals due to anthropogenic CO2 leaks anticipating future monitoring using these wells. Variations of seasonal mean and variance of CO2 concentrations at different depths seem to follow the diurnal trend of subsurface temperature changes that reflect the atmospheric temperature but with time delay and amplitude damping due to heat transport considerations. The temperature in the ground lags behind the change in the atmospheric temperature, thus, the deeper the depth, the longer the time delay and the smaller the amplitude of the change. Monitored seasonal variation as shown in Appendix A shows the temperature-dependent depth-dependent CO2 production in the soil zone indicating higher CO2 concentrations in the summer and fall seasons with high concentrations ranging between 10,990 and 51,600 ppm from spring to summer, and 40,100 and 17,760 ppm from fall to winter. As the temperature in the organic-rich topsoil layer changes from daytime to nighttime, the concentration of CO2 in the soils also changes dynamically in response to chemical and biological reactions. When a screened well is installed in the vadose zone the dynamic temporal and depth difference in CO2 production is further complicated by upward (out of the subsurface) or downward (into the subsurface) gas flow, which will amplify or attenuate the temporal and vertical biochemically produced differences. Nested wells screened at different depths in the vadose zone and wells fully screened through the vadose zone were used for comparison. In addition, experiments changing the well from open to surface air to sealed at the top were conducted. The flow rates of inhaled (downward) and exhaled (upward) gas were estimated based on multi-level monitoring data. Based on time-series monitoring data, we proposed a time-dependent conceptual model to explain the changes of CO2 concentration in wells. The conceptual model was tested through analytical model computations. This conceptual model of natural variation of CO2 will be helpful in utilizing the vadose zone well as a method for monitoring CO2 leakage from subsurface storage or anthropogenic CO2 -producing activities.
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Affiliation(s)
- Won-Tak Joun
- School of Earth and Environmental Sciences, Seoul National Univ., Seoul, 151-747, South Korea
| | | | - Woo-Jin Shin
- Division of Earth and Environmental Sciences, Ochang Center, Korea Basic Science Institute, South Korea
| | - Kang-Kun Lee
- School of Earth and Environmental Sciences, Seoul National Univ., Seoul, 151-747, South Korea.
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9
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Wang Y, Luo W, Zeng G, Wang Y, Yang H, Wang M, Zhang L, Cai X, Chen J, Cheng A, Wang S. High 222Rn concentrations and dynamics in Shawan Cave, southwest China. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 199-200:16-24. [PMID: 30641397 DOI: 10.1016/j.jenvrad.2018.12.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 09/23/2018] [Accepted: 12/27/2018] [Indexed: 05/22/2023]
Abstract
Cave 222Rn has been a major health issue and subject of scientific debate for decades. While the basics of natural ventilation physics are well understood, it is difficult to make blind predictions of 222Rn concentrations in a given cave due to the complexity of cave systems. In-situ continuous observation is necessary to improve our ability to quantify radiation dose exposure and reduce radiation hazard to cave users, and trace the air exchange patterns occurring in caves. In this study, continuous monitoring using a RAD7 radon detector revealed high 222Rn concentrations and large fluctuations in 222Rn concentration in a small karst cave in southwest China, Shawan Cave. From August 2016 to July 2017, the average annual concentration was 47,419 Bqm-3 and ranged between 3720 and 123,000 Bqm-3, with lower values during summer than other seasons. Taking Shawan Cave as a case study, we suggest a framework to evaluate the potential dose exposure, allowing cave users to minimize risk of exposure to hazardous levels of 222Rn. Furthermore, we comparing results from this study with other studies in 35 caves worldwide, and conclude that there are three patterns of seasonal 222Rn variation. They were classified into five types of ventilation mode based on diversity of cave locations, geometry and connectivity of bed rock fracture networks, together with temperature differences between outside atmosphere and cave air.
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Affiliation(s)
- Yanwei Wang
- University of Chinese Academy of Sciences, Beijing, 100049, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang, 550081, China
| | - Weijun Luo
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang, 550081, China; Puding Karst Ecosystem Research Station, CAS, Puding, 562100, China.
| | - Guangneng Zeng
- School of Chemistry and Eco-Environmental Engineering, Guizhou Minzu University, Guiyang, 550025, China
| | - Yang Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang, 550081, China
| | - Hanling Yang
- University of Chinese Academy of Sciences, Beijing, 100049, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang, 550081, China
| | - Meifang Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang, 550081, China; School of Geography and Environmental Sciences, Guizhou Normal University, Guiyang, 550025, China
| | - Lin Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang, 550081, China; Puding Karst Ecosystem Research Station, CAS, Puding, 562100, China
| | - Xianli Cai
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang, 550081, China; Puding Karst Ecosystem Research Station, CAS, Puding, 562100, China
| | - Jia Chen
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang, 550081, China; Puding Karst Ecosystem Research Station, CAS, Puding, 562100, China
| | - Anyun Cheng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang, 550081, China; Puding Karst Ecosystem Research Station, CAS, Puding, 562100, China
| | - Shijie Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang, 550081, China; Puding Karst Ecosystem Research Station, CAS, Puding, 562100, China
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