Radon Dynamics and Effective Dose Estimation in a Touristic Volcanic Cave: La Cueva del Viento, Tenerife (Canary Islands, Spain)

• Published in: Geohealth 2023-02, Vol.7 (2), p.e2022GH000704-n/a
• Main Authors: Salazar‐Carballo, Pedro A., López‐Pérez, María, Martín‐González, María Esther, Hernández‐Suarez, Francisco, Martín‐Luis, M. Candelaria
• Format: Article
• Language: English
• Subjects: Air temperature; cave; Caves; Dosimetry; Dry season; Exploitation; Frequency analysis; Geohealth; Health and Radiation; Islands; Lava; Legislation; Lung cancer; Radiation; radioprotection; Radon; Sensors; Tenerife; Time series; Tourists; Ventilation; Volcanoes
• ISSN: 2471-1403; 2471-1403
• DOI: 10.1029/2022GH000704

La Cueva del Viento is a volcanic lava tube located in Tenerife Island (Canary Islands, Spain). Its touristic section, 180 m long, receives more than 28,200 visitants each year. According to the European and Spanish legislation, a radon monitoring program is required to minimize the radon exposition of workers, tourists, and cavers. In this work, we studied the radon concentration dynamics in the touristic section of the cave for ca. 1 year, using both passive and active radon detectors. Pluviometry and external air temperature played an important role in the seasonal and daily variations of indoor radon concentrations. Daily fluctuations during the dry season were analyzed using time series (Box‐Jenkins methodology) and frequency analysis (Fourier and Wavelet transforms) methods. The experimental radon time‐series was well‐fitted using a seasonal autoregressive integrated moving average model: Seasonal Auto‐Regressive Integrated Moving Average (2,0,1) (2,1,0)24, and its value, in a short‐time window (ca. 1 week) was conveniently forecasted. Finally, this work revealed that the annual effective doses received, during the observation period (1 year), by the touristic guides and visitors was ca. 2 mSv/yr and 4 μSv/hr, respectively. We concluded that the touristic exploitation of La Cueva del Viento is safe for both tourists and guides. However, based on our results, La Cueva del Viento had to be classified as a “Monitoring zone” and a regular monitoring program should be implemented. Plain Language Summary La Cueva del Viento, a volcanic lava tube located in Tenerife Island (Canary Islands, Spain), receives more than 28,200 visitants each year. With 18.2 km in length, it is the sixth longest volcanic tube on Earth. In this work, we studied the radon concentration in the touristic section of about 180 m for ca. 1 year. The radon showed a complex dynamic behavior, with a clear seasonal component (lower values during the wet season and higher during the dry season). Based on the radon concentration profile we concluded that the touristic section of the volcanic tube was well ventilated and presented lower radon values than other adjacent parts. During this study, the radon concentration in the touristic sector ranged from 100 to 5,000 Bq/m3. Rain, temperature, and soil humidity played an important role in the in the behavior of the radon concentration in the long and short term. The present study revealed that the annual effective doses received by the touristi