Environmental isotope investigation of the river catchments

Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Tritium content in precipitation and atmospheric water vapour of the reactor hall in the Vinča institute of nuclear sciences

Tritium activity was determined in precipitation samples collected at two locations in Belgrade over the period 1998-2007: meteorological station Belgrade (Zeleno Brdo 44º47' N, 20º32' E, altitude 243.2m asl) and the station at the Vinča Institute of Nuclear Sciences. Tritium concentrations in precipitation ranged from 0.4 to 4.41 Bq l-1 (samples collected at Zeleno Brdo) and from 2.31 to 41.30 Bq l-1 (samples collected at VINS). Tritium content in atmospheric water vapour of the indoor reactor hall and inside of the reactor during the regular inspection of the fuel channels in the Vinča Institute of Nuclear Sciences in March and May 2006 was measured. The obtained results showed that the tritium content in HTO form varied from 1.56x102 Bq m-3 to 4.05x102 Bq m-3.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Sinusoidal coded model

This article discusses a usage of modified periodic harmonic analysis to prove the periodicity of experimental data for seasonal stable isotope variations in precipitation and stream water. A proof for sinusoidal coded model is based on a hypothesis concerning the importance of the first harmonic. The utility of proposed model was demonstrated on experimental data for oxygen isotope stream water content of the Velika Morava catchment over the period 2004-2007. This study suggests an applicability of sinusoidal coded model for more accurate estimation of mean residence time without a loss of theoretical or physical significance.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Protolytic equilibria and stability of quercetin in aqueous solutions

The protonation constant of carbonyl group and dissociation constants of -OH groups of quercetin were determined from the changes in UV and IR spectra of aqueous solutions of various acidities. The distribution diagram of ionic species was calculated. Besides, the stability of quercetin was investigated as the function of pH and concentration. The analysis of kinetic curves indicated that a noncatalyzed conversion took place together with the autocatalyzed degradation of quercetin.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Chemical characterization of potable mineral waters

This article discusses chemical characteristics of Serbian natural mineral watersin comparison to worldwide-recognized waters. The attempt has been made to range mineral waters in respect to the calculated statistical line of mineralization. A moving average method was adopted for the calculation of statistical representative points for the main ions content of mineral waters. Proposed mode for characterization specifies the pathway from low to high mineralized water accompanied with the changes in water chemical composition.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Precipitation chemistry in the Velika Morava catchment

Bulk precipitation chemistry on a daily basis was studied for seven years (1998-2004) at three meteorological stations (Smederevska Palanka, Kraljevo, Niš) in the Velika Morava catchment. Samples were analyzed for the anions Cl- , NO3 - and SO4 2-, and for the cations Na+ , NH4 + , K+ , Mg2+ and Ca2+ in addition to pH and conductivity measurements. The most abundant ion was SO4 2-, followed in descending order by Ca2+ > NH4 + > Mg2+ > Cl- > Na+ > NO3 - >K+ . A significant wet deposition of sulfate of 58-134 mmol.m-2.yr-1 was calculated caused by heating emission during combustion of lowquality sulfur-rich lignite.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Analysis of sinusoidal coded model: analysis of code

This article presents a procedure for transformation of measured data and application of the proposed sinusoidal coded model to fit better seasonal stable isotope variations in precipitation and stream water. The utility of proposed model was validated by the comparison between measured data and numerical evaluations for oxygen isotopic content in precipitation over the period 2004-2008. The proposed sinusoidal coded model offers an accurate fit with low standard deviation per month only with one fitting parameter

The measurement of tritium in water samples with electrolytic enrichment using liquid scintillation counter

Tritium (3H) present in the environment decreased in the last decades and nowadays it has low activity concentrations. Measurement of low-level tritium activities in natural waters, e. g. in precipitation, groundwater, and river water requires special techniques for water pretreatment and detection of low-level radioactivity. In order to increase the tritium concentration to an easily measurable level, electrolytic enrichment must be applied. This paper presents the enrichment method performed by electrolysis in a battery of 18 cells, giving an enrichment factor of 5.84 (calculated from 59 electrolyses). The calculated mean values of the separation factor and enrichment parameter were 4.10 and 0.84, respectively. Results for tritium activity in precipitation and surface water collected in Belgrade during 2008 and 2009 are presented. The Radiation and Environmental Protection Department of the Vinča Institute of Nuclear Sciences, participated in the IAEA TRIC2008 international intercomparison exercise. The participation in the intercomparisons for any laboratory doing low-level 3H measurements in the waters is very important and useful. It is considered the best way to check the entire procedure and methods of the measurements and the reliability of the standard used. The analysis of the reported 3H activity results showed that all results for five intercomparison samples, for which electrolytic enrichment were applied prior to the 3H measurement, are acceptable

Relationship between atmospheric circulation and stable isotope composition of Belgrade daily precipitation

Abstract Daily precipitation was collected in the period from May to December 2010, along with the corresponding meteorological data (air temperature, humidity, amount of precipitation) in the Vinca Institute of Nuclear Sciences (44°45′33″ N, 20°35′57″ E), Belgrade, Serbia. On the basis of backward trajectory analysis, three dominant trajectory categories are determined: southwestern Europe (SW), northeastern Europe (NE), and northwestern Europe (NW), which were associated with 49 (71%) of the events. The highest daily δ18O and δ2H values were measured on 9 December (−1.3‰ and −8.7‰, respectively), whereas the lowest values were measured on 28 December (−143.2‰ and −19.3‰, respectively). Circulation back trajectories, synoptic-scale surface and middle-tropospheric weather maps, and δ2H and δ2O values for 69 precipitation samples, were examined to determine the origin and direction of the air masses for each event

Spectrophotometric study of solution equilibria between Al3+ ion and L-histidine

Aluminium(III) ion and L-histidine (HHis) react in water solution to yield two mononuclear binary complexes [Al(HHis)]3+ and [Al(HHis)His] 2+. The over-all stability constants for these complexes were calculated by non-linearleast-squarestreatment of the spectrophotometric data and found to be: log β1,1,1 = 13.12 ± 0.04, log β1,2,1 = 20.9 ± 0.1, respectively. Indices refer to stoichiometric coefficients in complexation equilibrium: p Al + q His + r H → [AlpHisqHr]. The possible structures of the complexes in solution, are discussed.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200