The use of tracer gases to study the air exchange in the Altamira cave

Póster elaborado para la European Geosciences Union General Assembly, celebrada en Viena del 8 al 13 de abril de 2018

Continuous monitoring of radon gas as a tool to understand air dynamics in the cave of Altamira (Cantabria, Spain)

The use of radon as an atmospheric tracer in the Altamira Cave over the past 30 years has provided relevant information about gaseous exchanges between the Polychromes Room, the adjoining Chambers inside the cave, and the outside atmosphere. The relatively simple physico-chemical behaviour of radon gas provides a marked advantage over other tracer gases that are usually present in high concentrations in hypogeous environments, such as CO2. Two types of continuous radon measurement were undertaken. The first involves active detectors located in the Hall and Polychromes Room, which provide radon concentration values at 1-hour intervals. In addition, nuclear solid track etched detectors (CR-39) are used in every chamber of the cave over 14-day exposure periods, providing average radon concentrations. In this paper we show some of the specific degassing and recharge events identified by anomalous variations in the concentration of radon gas in the Polychromes Room. In addition, we update knowledge regarding the degree of connection between chambers inside the cave and with the outside atmosphere. We verify that the connection between the Polychromes Room and the rest of the cave has been drastically reduced by the installation of the second closure in 2008. Except for point exchanges with the Crossing zone generated by a negative temperature gradient in that direction, the atmosphere of the Polychromes Room remains stable, or else it exchanges matter with the outside atmosphere through the karst interface. The role of radon as a tracer is demonstrated to be valid both to reflect seasonal cycles of degassing and recharge, and to analyse shorter (daily) period fluctuations.This research was funded by the Project “Estudios analíticos para una propuesta de accesibilidad pública de la Cueva de Altamira” funded by the Ministry of Education, Culture and Sports, Spain (MECD)

The Laboratory of Natural Radiation (LNR) - a place to test radon instruments under variable conditions of radon concentration and climatic variables

The publication of the new European Union Basic Safety Standards represents a remarkable milestone in the fi eld of radiological protection in terms of adding radon exposure to this framework. Therefore, the coming years will bring the need to measure radon not only in the workplaces but also in the living spaces as a direct outcome of the application of the new EU Directive. So, the importance of having reliable instruments is evident and interlaboratory exercises are becoming more and more popular. However, most of them are carried out under constant conditions of meteorological variables. We present in this paper a facility to broaden the interlaboratory comparisons further by adding the study of radon exposures under real conditions of changes in climatic parameters. In addition, the facility has the possibility to verify the response of radon monitors when the radon concentration changes several orders of magnitude in a short period of time. Our work shows some results of one of the interlaboratory exercises carried out in the premises, where the radon levels were rather homogeneous in the testing room

Variations in radon dosimetry under different assessment approaches in the Altamira Cave

The atmosphere of caves is a special environment where it is necessary to take into account some particular characteristics when assessing the radon dose. The equilibrium factor (F) between radon and its progeny, and especially its unattached fraction ( fp), is a key parameter in radon dose evaluation. In order to consider the specific features of the atmosphere in the Altamira Cave, the radon and particle concentrations have been measured. The mean annual radon concentration inside the cave over the period 2013?2019 is around 3500 Bq m?3 with a standard deviation of 1833 Bq m?3 and this exhibits seasonal variations. This value surpasses all international (WHO, IAEA, ICRP) upper action and reference levels (occupational and non-occupational). Dose rate levels expressed in ?Sv h?1 were estimated for four different equilibrium scenarios between radon and its progeny 218Po, 214Pb, 214Bi and 214Po. The most recent dose conversion factors have been used and the contribution made to the dose by the unattached fraction of radon progeny fp has been also assessed from the particle concentration. The results suggest that the mean annual dose levels show variations of up to 500% due to the range of F and the fp considered in this study. Given the high radon concentrations usually found in show caves, the best way to reduce this variability and its associated uncertainty in dose assessment is to conduct specific studies aimed at determining both F and fp.This work was supported by the Ministry of Education, Culture and Sport of Spain (MECD) (grant number J180052) under the Project ‘Servicio de control y seguimiento de las condiciones ambientales y del biodeterioro de la Cueva de Altamira’, and The Cantabrian International Institute for Prehistoric Research (IIIPC)

Use of radon and CO2 for the identification and analysis of short-term fluctuations in the ventilation of the polychrome room inside the Altamira Cave

A study is presented on rapid episodes of air exchange in the Polychrome Room of the Altamira Cave (Cantabria, Spain) using continuous monitoring of radon and CO2 tracer gases, as well as environmental parameters such as internal and external air temperature. For this, criteria have been developed to carry out an inventory of these types of events during the 2015–2020 period. Most of the degassing-recharging events occur over several hours or days, especially during spring and autumn. This means that the room can be significantly ventilated during these short periods of time, posing an exchange of energy and matter with potential impact in the preservation of the rock art present inside. In addition, the hypothesis that temperature gradients between the internal and external atmosphere is one of the main factors that induces degassing has been tested.This research was funded by the Spanish Ministry of Culture and Sport, grant number J200028

Intercomparison of Indoor Radon Measurements Under Field Conditions In the Framework of MetroRADON European Project

Interlaboratory comparisons are a basic part of the regular quality controls of laboratories to warranty the adequate performance of test and measurements. The exercise presented in this article is the comparison of indoor radon gas measurements under field conditions performed with passive detectors and active monitors carried out in the Laboratory of Natural Radiation (LNR). The aim is to provide a direct comparison between different methodologies and to identify physical reasons for possible inconsistencies, particularly related to sampling and measurement techniques. The variation of radon concentration during the comparison showed a big range of values, with levels from approximately 0.5 to 30 kBq/m3. The reference values for the two exposure periods have been derived from a weighted average of participants' results applying an iterative algorithm. The indexes used to analyze the participants' results were the relative percentage difference D(%), the Zeta score ( ? ), and the z-score ( z ). Over 80% of the results for radon in air exposure are within the interval defined by the reference value and 20% and 10% for the first and the second exposure, respectively. Most deviations were detected with the overestimating of the exposure using passive detectors due to the related degassing time of detector holder materials.This research was funded by the European Metrology Programme for Innovation and Research (EMPIR), JRP‐Contract 16ENV10 MetroRADON (http://www.euramet.org). The EMPIR initiative is co‐funded by the European Union’s Horizon 2020 research and innovation programme and the EMPIR Participating States

Identifying the Presence of Natural Radionuclides in Ashlar Samples

Humans have always been exposed to different types of natural and cosmic radiation. At present we experience 83 % natural radiation, for example from granite marbles, building materials such as concrete, brick, granite, or drywall. However, although these are potential sources of radon, they are rarely the cause of a high level of pollution in a building.Ashlar is a material of volcanic origin comprising heterogeneous and solidified detrital pyroclastic materials such as rhyolite, sand, volcanic ash and pumice, among others. Chemically, ashlar is principally composed of elements such as sodium, magnesium, calcium, iron, aluminum, sulfur, and cobalt. In order to identify the presence of these elements in the ashlar, X-ray Fluorescence studies were carried out first, using modern XRD and XRF equipment, followed by quantitative analysis using a neutron activation technique, and finally, low-level gamma spectrometry to evaluate the presence of radioactive elements

Spanish experience on the design of radon surveys based on the use of geogenic information

One of the requirements of the recently approved EU-BSS (European Basic Safety Standards Directive, EURATOM, 2013) is the design and implementation of national radon action plans in the member states (Annex XVIII). Such plans require radon surveys. The analysis of indoor radon data is supported by the existing knowledge about geogenic radiation. With this aim, we used the terrestrial gamma dose rate data from the MARNA project. In addition, we considered other criterion regarding the surface of Spain, population, permeability of rocks, uranium and radium contain in soils because currently no data are available related to soil radon gas concentration and permeability in Spain. Given that, a Spanish radon map was produced which will be part of the European Indoor Radon Map and a component of the European Atlas of Natural Radiation. The map indicates geographical areas with high probability of finding high indoor radon concentrations. This information will support legislation regarding prevention of radon entry both in dwellings and workplaces. In addition, the map will serve as a tool for the development of strategies at all levels: individual dwellings, local, regional and national administration

Oteiza: Fotografía y espacio

Oteiza used much photography as an auxiliary tool for the development and analysis of his work, although he is best known for his models or drawings. This research wants to focus the photographs of Oteiza like a procedding, because he used them to experience the spatial qualities of his sculptures. We will analyze the 3D resources present in many of the more than 7,000 photographs held in the archives of the Oteiza Foundation. First, we will identify the spatial, visual and formal intentions with which Oteiza used the image. And then, we will do a current photographic interpretation to analyze his sculptures from an architectural point of view, which is very appropriate for 3D objects. This depiction will show didactically the Oteiza research around the void.Oteiza usa abundantemente la fotografía como herramienta auxiliar para el desarrollo y análisis de su obra, aunque son más conocidas sus maquetas o dibujos. Esta investigación pretende estudiar las fotografías procesuales de Oteiza, puesto que las consideraba un instrumento clave de trabajo para experimentar las cualidades espaciales de sus esculturas. Para ello, se analizarán los recursos tridimensionales presentes en muchas de las más de 7.000 fotografías que se conservan en los archivos de su Fundación. Una vez identificadas las intenciones espaciales, plásticas y formales con las que Oteiza utilizaba la imagen, se realizará una interpretación fotográfica actual que permita analizar sus esculturas desde un punto de vista arquitectónico, muy apropiado para unos objetos que investigan sobre todo el espacio. Este levantamiento servirá de conclusión gráfica que muestre didácticamente las investigaciones de Oteiza en torno al vacío significativo

Twitter as a Tool for Teaching and Communicating Microbiology: The #microMOOCSEM Initiative

Online social networks are increasingly used by the population on a daily basis. They are considered a powerful tool for science communication and their potential as educational tools is emerging. However, their usefulness in academic practice is still a matter of debate. Here, we present the results of our pioneering experience teaching a full Basic Microbiology course via Twitter (#microMOOCSEM), consisting of 28 lessons of 40-45 minutes duration each, at a tweet per minute rate during 10 weeks. Lessons were prepared by 30 different lecturers, covering most basic areas in Microbiology and some monographic topics of general interest (malaria, HIV, tuberculosis, etc.). Data analysis on the impact and acceptance of the course were largely affirmative, promoting a 330% enhancement in the followers and a >350-fold increase of the number of visits per month to the Twitter account of the host institution, the Spanish Society for Microbiology. Almost one third of the course followers were located overseas. Our study indicates that Massive Online Open Courses (MOOC) via Twitter are highly dynamic, interactive, and accessible to great audiences, providing a valuable tool for social learning and communicating science. This strategy attracts the interest of students towards particular topics in the field, efficiently complementing customary academic activities, especially in multidisciplinary areas like Microbiology.Versión del edito