Use of 137 Cs isotopic technique in soil erosion studies in Central Greece

The 137Cs technique was used to study soil erosion and deposition rates in soils in the Viotia prefecture, central Greece. Three sites with different soil types were selected and studied. Soils were sampled along transects and analyzed for 137Cs. The main goal of this field investigation was to study the 137Cs 3-D distribution pattern within key sites and to apply this information for the assessment of soil redistribution. The erosion and deposition rates were estimated using the proportional and the simplified mass balance models (Walling and He, 1997). Erosion and deposition rates predicted through the spatial distribution of 137Cs depended on the location of the profile studied in the landscape and were determined by the soil plough depth, the soil structure (bulk density), and the calibration model used to conve rt soil 137Cs measurements to estimates of soil redistribution rates. Estimated erosion rates for the Mouriki area site, varied from 16.62 to 102.56 t ha-1 y-1 for the top of the slope soil profile and from 5.37 to 25.68 t ha-1 y-1 for the middle of the slope soil profile. The deposition rates varied from 7.26 to 42.95 t ha-1 y-1 for the bottom of the slope soil profile

Use of 137 Cs isotopic technique in soil erosion studies in Central Greece

The 137Cs technique was used to study soil erosion and deposition rates in soils in the Viotia prefecture, central Greece. Three sites with different soil types were selected and studied. Soils were sampled along transects and analyzed for 137Cs. The main goal of this field investigation was to study the 137Cs 3-D distribution pattern within key sites and to apply this information for the assessment of soil redistribution. The erosion and deposition rates were estimated using the proportional and the simplified mass balance models (Walling and He, 1997). Erosion and deposition rates predicted through the spatial distribution of 137Cs depended on the location of the profile studied in the landscape and were determined by the soil plough depth, the soil structure (bulk density), and the calibration model used to conve rt soil 137Cs measurements to estimates of soil redistribution rates. Estimated erosion rates for the Mouriki area site, varied from 16.62 to 102.56 t ha-1 y-1 for the top of the slope soil profile and from 5.37 to 25.68 t ha-1 y-1 for the middle of the slope soil profile. The deposition rates varied from 7.26 to 42.95 t ha-1 y-1 for the bottom of the slope soil profile

INDOOR RADON MEASUREMENTS IN PATRAS, GREECE, WITH SOLID STATE NUCLEAR TRACK DETECTORS

Measurements of indoor radon ( 222 Rn) concentrations were carried out by using LR-115 II solid state nuclear track detectors (SSNTD). One hundred forty detectors were placed randomly in Patras houses for two periods of three months exposure, from December 1996 to November 1997. The observed mean radon values compared with the standard recommended values are low, while the maximum recorded value is found to be within the limits. The influence of seasonal variation as well the distance from the ground on radon level were also investigated. Key wordw: Radon; 222 Rn; radioactivity, indoor; solid state nuclear track detector; LR-115 II. INTRODUCTION Over the last 15 years scientists and the general public have become aware of the risk associated with indoor air pollution and particularly the risk from exposure to radon in dwellings. This increasing interest in indoor radon concentrations is demonstrated by several recent reports Many techniques are used for radon measurements inside dwellings. The solid state nuclear track detector (SSNTD) technique is one of the most reliable for integrated and long-term measurement of indoor radon concentration EXPERIMENTAL Materials and methods Indoor air radon concentrations were measured by the LR 115-II detectors in a "closed-can" arrangement using an optimized technique. This technique is described in details elsewhere 040 Radon in the Living Environment, 19-23 April 1999, Athens, Greece 386 seasonal variation in radon concentrations. Diffusion chambers were also exposed in different floors of the same buildings in order to examine the influence in radon concentrations on the distance from the soil. Etching and counting procedures After three month exposure, the detectors were etched for 145 minutes in 2.5 N analytial grade NaOH solution at a constant temperature of 60.0 ± 0.5 °C. After the etching, the detectors were washed for 30 minutes with flowing cold water, then with distilled water and finally dryied in air. The track counting technique, which was performed using a slide projector (Kodak 5000) is described in details elsewhere Calibration The calibration was performed by exposing 3 diffusion chambers in a radon chamber maintained by the Nuclear Technology Laboratory in the National Technical University of Athens. For the purposes of this calibration, the diffusion chambers were exposed to an integrated radon concentration of 4.89 x 10 5 Bq h m -3 . The mean track density of these diffusion chambers was 1136 ± 27 Bq cm . RESULTS AND DISCUSSION The results of the radon measurements are presented in CONCLUSIONS The indoor radon concentration depends, mainly, on the nature of the soil surrounding the house and on the air-exchange rate. The average radon concentrations recorded in Patras houses are relatively low and within the EU recommended reference levels (the higher value is 180 Bq m -3 ). This may be due to the low 238 U concentration in soil and to the warm climate, which allows higher ventilation rates. The higher frequent low values recorded in summer exposure period than in autumn may be due to the higher ventilation rates in summer than in autumn

Indoor radon concentrations in Athens determined with an optimised etched track detector technique

Δημοσίευση σε επιστημονικό περιοδικόSummarization: A simple variant of the etched track detector methodology has been developed and used for a preliminary survey of the indoor radon concentrations in Athens. Certain parameters and techniques of the method have been optimised. The preliminary results are briefly discussed.Presented on

Trace elements and radioactivity in aerosol particles, produced in the area of Ptolemais (Greece)

Δημοσίευση σε επιστημονικό περιοδικόSummarization: Most of the Greek lignite power plants have been installed in the area of Ptolemais, and a major part of them during the period 1981–1990. Aerosol filters collected in the first and the last years of the decade have been analysed for trace elements as well as for radioactivity (total beta) content. Analysis was performed by radioisotope excited X-ray fluorescence, and 17 elements were determined. A special interest is focused on lead concentrations, an element whose environmental concentrations are regulated by the Greek law; the results for lead were validated by atomic absorption spectrometry. Trace element and radioactivity levels were found significantly lower than the current limit. Enrichment factors and correlation among the analysed elements were also estimated.Presented on: Journal of Radioanalytical and Nuclear Chemistr

Size distributions of airborne radionuclides from the fukushima nuclear accident at several places in europe

International audienceSegregation and radioactive analysis of aerosols according to their aerodynamic size were performed in France, Austria, the Czech Republic, Poland, Germany, and Greece after the arrival of contaminated air masses following the nuclear accident at the Fukushima Dai-ichi nuclear power plant in March 2011. On the whole and regardless of the location, the highest activity levels correspond either to the finest particle fraction or to the upper size class. Regarding anthropogenic radionuclides, the activity median aerodynamic diameter (AMAD) ranged between 0.25 and 0.71 μm for 137Cs, from 0.17 to 0.69 μm for 134Cs, and from 0.30 to 0.53 μm for 131I, thus in the "accumulation mode" of the ambient aerosol (0.1-1 μm). AMAD obtained for the naturally occurring radionuclides 7Be and 210Pb ranged from 0.20 to 0.53 μm and 0.29 to 0.52 μm, respectively. Regarding spatial variations, AMADs did not show large differences from place to place compared with what was observed concerning bulk airborne levels registered on the European scale. When air masses arrived in Europe, AMADs for 131I were about half those for cesium isotopes. Higher AMAD for cesium probably results from higher AMAD observed at the early stage of the accident in Japan. Lower AMAD for 131I can be explained by the adsorption of gaseous iodine on particles of all sizes met during transport, especially for small particles. Additionally, weathering conditions (rain) encountered during transport and in Europe in March and April contributed to the equilibrium of the gaseous to total 131I ratio. AMAD slightly increased with time for 131I whereas a clear decreasing trend was observed with the AMADs for 137Cs and 134Cs. On average, the associated geometric standard deviation (GSD) appeared to be higher for iodine than for cesium isotopes. These statements also bear out a gaseous 131I transfer on ambient particles of a broad size range during transport. Highest weighted activity levels were found on the 0.49-0.95 μm and on the 0.18-0.36 μm size ranges in France and in Poland, respectively. The contribution from resuspension of old deposited 137Cs was assessed for the coarse particle fractions only for the first sampling week. © 2013 American Chemical Society