M. Vesković

Public exposure to radon in drinking water in Serbia.

Radon is the main source of natural radiation that is received by population. The results of radon activity measurements in water from public drinking fountain, from bottled drinking water and from tap water in the city of Novi Sad, Serbia, are presented in this paper. The measurements were performed by RAD 7 radon detector manufactured by DURRIDGE COMPANY Inc. The corrected value of radon concentration in one sample exceeded the European Commission recommendation reference level for radon in drinking water of 100 Bql(-1). In order to make the correlation between radon and radium concentrations in the tap water and in the water from public drinking fountain, the gamma-spectrometric measurements were performed. The results of (222)Rn activity concentration measurements from soil in the city of Novi Sad using RAD 7 detector are presented.

Airborne radioiodine in northern Serbia from Fukushima

The results obtained with the monitoring system set up to assess the impact of the Fukushima accident on the environment of Vojvodina (Northern Province of Serbia) are presented and discussed. Aerosol, rain, fresh milk and spinach samples were collected daily in the weeks following the accident. In the aerosol samples, (131)I activity concentrations of several mBq m(-3) were measured, while in rain, milk and spinach samples, (131)I levels had values in a range of (0.3-1.7) Bq kg(-1). These are the first results on the impact of the Fukushima accident on the Pannonian basin region. Our results are compared with the reported values from other parts of the world.

Simple Method for Depleted Uranium Determination

When the issue of depleted uranium (DU) presence in the environment emerged, methods for analytical discrimination of DU against natural uranium should be developed. We present here a simple gamma-spectrometric method, based on the 238U–226Ra activity (non) equilibrium. The detection limit of the method for DU is of the order of magnitude of 10 Bq/kg (for about 50 ks counting), thus the method is appropriate for the determination of small amounts (≈100 Bq/kg) of DU in environmental samples. The method is tested on about 90 soil samples.

Evaluation of bremsstrahlung spectra generated by a 4‐MeV linear accelerator

A modified method for the evaluation of bremsstrahlung spectra on the basis of transmission measurements is presented. The method is tested for two 4 MeV therapy accelerators. The calculated spectra are compared with other experimental results and Monte Carlo simulation.

Methods of radon measurement

Several important international scientific organizations have designated radon as a carcinogenic and serious health problem. As a chemically inert gas, it is easily released from soil, building materials, and water, to emanate to the atmosphere. Since 1992, Laboratory for Nuclear Physics of the Department of Physics, Faculty of Sciences in Novi Sad has been involved in measurements of radon concentration in air, using several different techniques. Last year, systematic radon measurements in drinking waters began, too. The work presented here gives a survey and discussion of the results of the both series of measurements.

Monitoring for exposures to TENORM sources in Vojvodina region

TENORM are found in a wide variety of waste materials, some raw mineral ores and in some consumer products (in trace amounts) where molecules of radionuclides may be bound to specific minerals used in the manufacturing process and can result in increases in radiation exposures to workers and the public. The aim of this paper is to understand this problem and to develop effective ways to protect humans and the environment from harmful exposure to the radiation in TENORM materials in the Vojvodina region. The results of measurement of indoor radon concentration in schools and kindergartens and dose-rate and gamma-spectrometry measurements of the workplace with TENORM materials are presented.

Elimination of long lived fission products from river sediment

Abstract The activity concentration of 137 Cs, 134 Cs and 106 Ru in the sediment of the Danube river was measured for a period of 18 months after the Chernobyl accident. From the data fitted with a simple exponential decay function the same value of “corrected elimination half-life” T ec ≈ 240 d was derived for all three radionuclides.

Different methods for tritium determination in surface water by LSC

The main aim of this paper was to compare different methods of preparing water samples for tritium analysis by ultra-low-level background liquid scintillation counter, Quantulus 1220. Three methods of sample preparation for low-level tritium measurement have been implemented in the Nuclear Physics Laboratory in Novi Sad: electrolytic enrichment, direct method without electrolytic enrichment and sample Oxidizer 307 method. The examined fresh water samples were rainfall collected during 6 months and water from a stream in the Vinča nuclear research center collected over 3 months. The obtained results using these three methods showed satisfying agreement. The appropriate measuring time by LSC for each sample prepared according to different methods has been determined.

Improvement of measuring methods and instrumentation concerning 222Rn determination in drinking waters – RAD7 and LSC technique comparison

A procedure for the determination of (222)Rn in environmental water samples using liquid scintillation counting (LSC) was applied and optimized. A minimum detectable activity of 0.029Bql(-1) in a 20ml glass vial (10ml water sample mixed with 10ml of liquid scintillation cocktail) has been achieved during 300min of measurement time. The procedure was compared with RAD7 radon detector measurements. (226)Ra content in the water was determined by gamma-ray spectroscopy. Applications to drinking waters collected from public drinking fountains in the Vojvodina (Serbia) are presented with annual effective dose for ingestion and inhalation for adults calculated.

Determination of the optimal length of cylindrical sources for specific gamma activity measurements

Abstract A simple and general approximate method for the determination of the optimal length of cylindrical gamma ray sources is presented.