Asta Gregorič

Systematic survey of natural radioactivity of soil in Slovenia

Soil samples, from 70 points uniformly distributed over entire Slovenia, were analysed for (40)K, (232)Th and (226)Ra using gamma spectrometry, and for (234)U and (238)U using alpha spectrometry. The following ranges and averages of activity concentrations (Bq kg(-1)) were obtained: 98-2600 and 800 ± 520 for (40)K, 9-170 and 77 ± 33 for (232)Th, 12-270 and 63 ± 44 for (226)Ra, 12-84 and 34 ± 19 for (234)U, and 11-90 and 34 ± 19 for (238)U. With respect to lithology, the highest average values for (40)K and (232)Th were found at clastic sediments containing clay and for (226)Ra on carbonate rocks. Based on the measured activity concentrations, terrestrial gamma dose rates were calculated. The total dose rate ranged from 15 to 260 nGy h(-1), with arithmetic mean of 110 ± 49 nGy h(-1), being the highest over carbonates.

Dependence of radon emanation of soil on lithology

In soil samples collected from 58 points of 7 different lithological units that appear most often in Slovenia, emanation fraction of 222Rn and porosity have been determined. Emanation fraction ranged from 0.010 to 0.547 and varied substantially among lithological units, as well as within the same lithological unit. The highest average value was found in soil over sea and lake deposits (0.340) and the lowest, over metamorphic rocks (0.029). Based on the data measured, radon concentration in soil gas was calculated and compared with the values obtained previously at the same points by exposing solid state nuclear track detectors.

Radon as an Earthquake Precursor – Methods for Detecting Anomalies

Radon is one of many geophysical and geochemical phenomena that can be considered to be an earthquake precursor. Due to the non-linear dependence of earthquakes’ initial conditions, the question about the predictability of earthquakes often arises (Geller, 1997). The successful prediction of earthquakes is yet to be accomplished, in terms of their magnitude, location and time, and much effort has been spent on this goal. The term “earthquake precursor” is used to describe a wide variety of geophysical and geochemical phenomena that reportedly precede at least some earthquakes (Cicerone et al., 2009). The observation of these types of phenomena is one recent research activity which has aimed at reducing the effects of natural hazards. Among the different precursors, geochemistry has provided some high-quality signals, since fluid flows in the Earth’s crust have a widely recognised role in faulting processes (Hickman et al., 1995). The potential of gas geochemistry in seismo-tectonics has been widely discussed by Toutain and Baubron (1999). In the late 1960s and early 1970s, reports from seismically active countries such as the former USSR, China, Japan and the USA (Ulomov & Mavashev, 1967; Wakita et al., 1980) indicated that concentrations of radon gas in the earth apparently changed prior to the occurrence of nearby earthquakes (Lomnitz, 1994). The noble gas radon (222Rn) originates from the radioactive transformation of 226Ra in the 238U decay chain in the Earth’s crust. Since radon is a radioactive gas, it is easy and relatively inexpensive to monitor instrumentally, and its short half-life (3.82 days) means that short-term changes in radon concentration in the earth can be monitored with a very good time resolution. Radon emanation from grains depends mainly on their 226Ra content and their mineral grain size, its transport in the earth being governed by geophysical and geochemical parameters (Etiope & Martinelli, 2002), while exhalation is controlled by hydrometeorological conditions. The stress-strain developed within the Earth’s crust before an earthquake leads to changes in gas transport and a rise of volatiles from the deep earth up to the surface (Ghosh et al., 2009; Thomas, 1988), resulting in anomalous changes in radon concentration. The mechanism of observed radon anomalies is still poorly understood, although several theories have been proposed (Atkinson, 1980; King, 1978; Lay et al., 1998; Martinelli, 1991). Over the past three decades, the occurrence of anomalous temporal

The filter loading effect by ambient aerosols in filter absorption photometers depends on the mixing state of the sampled particles

[1] Research and Development Department, Aerosol d.o.o., Ljubljana, Slovenia [2] Condensed Matter Physics Department, Jožef Stefan Institute, Ljubljana, Slovenia 10 [3] Center for Atmospheric Research, University of Nova Gorica, Nova Gorica, Slovenia [4] Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), 5232 Villigen PSI, Switzerland [5] Institut National de l’Environnement Industriel et des Risques, Verneuil-en-Halatte, France [6 ]Laboratoire des Sciences du Climat et de l’Environnement (CNRS-CEA-UVSQ), CEA Orme des Merisiers, Gif-sur-Yvette, France 15 [7] Energy Environment and Water Research Center,The Cyprus Institute, Nicosia, Cyprus [8] Desert Research Institute, Nevada System of Higher Education, Reno, USA [9] MTA-SZTE Research Group on Photoacoustic Spectroscopy, Department of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary [#] now at: Lucerne University of Applied Sciences and Arts, School of Engineering and Architecture, 20 Bioenergy Research, Horw, Switzerland [

Dissolved radon and gaseous mercury in the Mediterranean seawater.

] now at: Air Lorraine, Metz, France [+] now at: Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, MO, USA [%] now at: College of Optical Sciences, University of Arizona, Tucson, AZ, USA 25

Intrinsic vulnerability of the Isonzo/Soča high plain aquifer (NE Italy – W Slovenia)

Vertical profiles of radioactive radon gas ((222)Rn) and dissolved gaseous mercury (DGM) in seawater in the Mediterranean Basin have been measured. They were found in the range 1.7-19.3 Bq m(-3) and 22-200 ng m(-3), respectively, at the bottom and 2.0-20.0 Bq m(-3) and 6-80 ng m(-3), respectively, at the surface. Preliminary results indicate a positive correlation between concentrations of both gases at some locations, but not at others. Further analyses will be performed, after (226)Ra contents in sediment and water have been determined, taking into account environmental parameters such as air and water temperatures, barometric pressure and water flow, in order to better interpret these profiles.

Radon dynamics in a dwelling with high radon levels in a karst area

ABSTRACT The paper presents the map of intrinsic groundwater vulnerability of the Isonzo/Soča High Plain, which is located between the Collio Hills and the Classical Karst Region and holds an aquifer shared between Italy and Slovenia. The map, produced at a scale of 1:25,000 and printed in A0 format, was obtained by means of the SINTACS method and shows the intrinsic vulnerability of the aquifer in terms of seven vulnerability classes, from extremely high to low. It is accompanied by four supplementary sketches that illustrate the geological framework, the bedrock top surface, the groundwater flow paths, the Hazard Index map and three diagrams that summarize the percentages of vulnerability classes and of Hazard Index classes of the study area.

Comparison of Approaches in Slovenia and Kazakhstan in Managing Exposure to Radon

Abstract Year-long continuous radon monitoring was carried out (using Sarad Radon Scout devices) in a dwelling with high radon levels in the karst region of Slovenia. Two living rooms were selected: one on the ground floor with normal housework activities; and the second, on the first floor, closed and unattended. Meteorological data were also recorded. The following seasonal geometric means of radon activity concentration (kBq m−3) have been found: 6.28×/: 3.05 for spring, 1.25×/: 3.78 for summer, 5.17×/: 2.03 kBq m−3 for autumn and 9.83×/: 1.48 for winter on the ground floor; and 1.43×/: 3.71 for spring, 0.168×/: 2.49 for summer, 1.08×/: 2.39 for autumn and 2.08×/: 2.14 for winter on the first floor. Results are supported by additional radon measurements in other rooms; and in water the results indicate a strong radon source associated with an underground karst shaft.

Heating Rate of Light Absorbing Aerosols: Time-Resolved Measurements, the Role of Clouds, and Source Identification

Increasing attention has been paid to radon in both Slovenia and Kazakhstan. The paper reviews their activities in radon measurements and dose estimates for radon exposure mitigation. Slovenia succeeded to accomplish the main goal of managing exposure to radon in homes and at workplaces at acceptably low levels, while in Kazakhstan there are still quite a number of dwellings with potential radon risk needing further monitoring and mitigation measures.

Mercury in the unconfined aquifer of the Isonzo/Soca River alluvial plain downstream from the Idrija mining area

Light absorbing aerosols (LAA) absorb sunlight and heat the atmosphere. This work presents a novel methodology to experimentally quantify the heating rate (HR) induced by LAA into an atmospheric layer. Multiwavelength aerosol absorption measurements were coupled with spectral measurements of the direct, diffuse and surface reflected radiation to obtain highly time-resolved measurements of HR apportioned in the context of LAA species (black carbon, BC; brown carbon, BrC; dust), sources (fossil fuel, FF; biomass burning, BB), and as a function of cloudiness. One year of continuous and time-resolved measurements (5 min) of HR were performed in the Po Valley. We experimentally determined (1) the seasonal behavior of HR (winter 1.83 ± 0.02 K day-1; summer 1.04 ± 0.01 K day-1); (2) the daily cycle of HR (asymmetric, with higher values in the morning than in the afternoon); (3) the HR in different sky conditions (from 1.75 ± 0.03 K day-1 in clear sky to 0.43 ± 0.01 K day-1 in complete overcast); (4) the apportionment to different sources: HRFF (0.74 ± 0.01 K day-1) and HRBB (0.46 ± 0.01 K day-1); and (4) the HR of BrC (HRBrC: 0.15 ± 0.01 K day-1, 12.5 ± 0.6% of the total) and that of BC (HRBC: 1.05 ± 0.02 K day-1; 87.5 ± 0.6% of the total).