Radon-222 signatures of natural ventilation regimes in an underground quarry
| Autor: | C. Crouzeix, Patrick Richon, Jean Louis Le Mouël, Pierre Morat, Frédéric Perrier |
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| Rok vydání: | 2004 |
| Předmět: |
Health
Toxicology and Mutagenesis Underground mining (hard rock) chemistry.chemical_element Radon Air current Cantera Mining law.invention law medicine Soil Pollutants Radioactive Environmental Chemistry Waste Management and Disposal Hydrology Atmospheric pressure Temperature Natural ventilation General Medicine Seasonality medicine.disease Pollution Ventilation chemistry Ventilation (architecture) Environmental science France Seasons Environmental Monitoring |
| Zdroj: | Journal of Environmental Radioactivity. 71:17-32 |
| ISSN: | 0265-931X |
| DOI: | 10.1016/s0265-931x(03)00117-6 |
| Popis: | Radon-222 activity concentration has been monitored since 1999 in an underground limestone quarry located in Vincennes, near Paris, France. It is homogeneous in summer, with an average value of 1700 Bq m(-3), and varies from 730 to 1450 Bq m(-3) in winter, indicating natural ventilation with a rate ranging from 0.5 to 2.4 x 10(-6) s(-1) (0.04-0.22 day(-1)). This hypothesis is supported by measurements in the vertical access pit where, in winter, a turbulent air current produces a stable radon profile, smoothly decreasing from 700 Bq m(-3) at 20 m depth to 300 Bq m(-3) at surface. In summer, a thermal stratification is maintained in the pit, but the radon-222 concentration jumps repeatedly between 100 and 2000 Bq m(-3). These jumps are due to atmospheric pressure pumping, which induces ventilation in the quarry at a rate of about 0.1 x 10(-6) s(-1) (0.009 day(-1)). Radon-222 monitoring thus provides a dynamical characterisation of ventilation regimes, which is important for the assessment of the long-term evolution of underground systems. |
| Databáze: | OpenAIRE |
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