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- Author or Editor: P. Kovács x
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Abstract
Except the nuclear fuel reprocessing and nuclear materials safeguards, at present there are two areas of an increased responsibility of nuclear scientists for their results: radioecology and human medicaments. At both of them, quality and trustfulness of results is of great importance for their end-users and may have serious economical and legal consequences. The trends of implementation of good laboratory and manufacturing practices under umbrella of international quality management standards like ISO 17025:2005 and ISO 9001:2000 in radiochemical and radiopharmaceutical laboratories are discussed as expanding to “good scientific practice”. The case studies of the Comenius University laboratory LARCHA authorized for radiochemical analysis, and the company BIONT producing medical radionuclides and PET radiopharmaceuticals are used as the examples.
The statistical analysis of salinity data from samples collected yearly from genetic soil horizons of 69 points of the Hungarian Soil Information and Monitoring System between 1992 and 2000 showed changes in time. There is a strong atmospheric control over the groundwater level and the resulting soil salinity. Weak statistical association was established between either the pattern of yearly soil salinity changes in the second (10-20 cm) and third (30-40 cm) genetic horizon and the groundwater observation stations or the soil types. In the area of Kecskemét there was a tendency of decreasing soil salinity patterns, while around Békéscsaba a tendency of increasing soil salinity patterns, as illustrated by the correspondence biplot. Regarding soil types, the solonetzic meadow soil showed a tendency of increasing salinity. It was concluded that the statistical analyses of the monitored data must be carefully planned in order to provide the optimal background data as independent data from all those available to accompany the monitored soil data as dependent variable.
The aim of the present study is a better understanding of the distribution and formation of salt efflorescences by mineralogical examination. Dominant sodium sulphate and sodium chloride surface efflorescences were selected for investigation. 24 samples were collected between 1999 and 2005 from 16 sites. The soil types were solonchak and meadow solonetz.Basic soil and groundwater analyses were performed according to the standard methods. Minerals were determined by X-ray diffractometry and SEM combined with microanalysis. The evaporation experiments were carried out in a Sanyo Versatile 350 HT environmental test chamber.It was concluded that common sulphate salts form rare and unique mineral associations on salt affected soils in Hungary.Comparing the groundwater compositions and the mineral associations of surface efflorescences or that of precipitated evaporites of groundwaters, the conclusion can be drawn that groundwater composition is reflected much better by the mineral association of experimentally precipitated evaporates of the groundwater than by the mineral associations of surface efflorescences. These differences suggest that the soil matrix may have an effect on the crystallization of minerals (e.g. gypsum, thenardite) in the efflorescences. The differences also suggest that in the surface efflorescences the precipitation process does not come to the end in all cases (minerals with high solubility are missing).Concerning the data on groundwater level depths in case of different (sodium carbonate versus sodium sulphate and sodium chloride) efflorescences, there is a tendency of declining groundwater table in the sequence of these soils. This difference can be explained by the difference (increase) in the solubility of various salt minerals.It was recognized that the change in the major component of surface efflorescenes in time (i.e. the sodium carbonate and sodium carbonate chloride versus sodium sulphate efflorescences before and after 1998) can be explained by the decline of the groundwater level and by the decreasing hydromorphic influence in the lowland area during the 19th and 20th century.Finally it can be stated that the presented research — which mainly focused on mineralogical aspects — has contributed to the earlier knowledge on surface salt efflorescences, which was based only on their chemical composition.
Abstract
Various cation-exchanged montmorillonites (Li+, Na+, Ba2+, Mg2+, Ca2+, Mn2+, Co2+, Cu2+, Ag+, Cd2+, Hg2+, Al3+, Pb2+ and NH4+) were prepared from calcium montmorillonite and their properties were studied by means of X-ray diffraction and thermal analysis. The two methods give information on the cation exchange in the interlayer space only. X-ray diffraction studies at room temperature are mainly suitable for estimation of the exchange of cations of different valencies. At 500C, when the structure is completely collapsed, the d value of montmorillonite depends on the non-hydrated ionic radius of the interlayer cation, but the measurement interval is limited for fine interpretation. The thermoanalytical method is suitable for a better distinction of different exchangeable cations of higher hydration energy on the basis of the DTG or DDTG curve.
Abstract
The Pb and Br content of plants growing along roads has been determined. It has been stated that the Pb-content of rye grass is proportional to the level of public road traffic. The Pb-content of plants cannot be removed by washing. The Pb, Cu and Zn-concentration of plants grown in the vicinity of smeltery may reach the 10–1000 times value of the normal level.
Abstract
The paper presents the kinetic study of the crystallization processes which take place in basalt glasses containing variable amount of nucleation agent (CaF2, 310%). The activation energies have been calculated using Kissinger's equation and verified with the Ozawa-Flynn-Wall equation. In this order, the DTA curves have been registered with different heating rates, between 4 and 20 degrees/min. A correlation equation between the activation energy and the amount of nucleation agent (% of CaF2) was established. By X-ray diffraction it was proved that the crystalline phase formed in the crystallization process represents a pyroxenic solid solution, Ca(Mg,Fe)SiO3.
The applicability of the chloroform fumigation extraction method was tested for detecting soil microbial biomass and p-nitrophenyl phosphate (pNP) for acid phosphatase activity to study their response to heavy metal pollution in the rhizosphere soil of planted willow (Salix sp.). The experimental site was located in the Toka River Valley (North-East Hungary) along the riverbank that had been severely polluted by flooding. The river had transported heavy metal and arsenic ions from several heaps deposited imprudently near a historic lead and zinc mining site. A phytoremediation experiment was set up by planting willow trees with the aim of extracting toxic elements from the soil. A strong significant difference between the control and the metal-contaminated rhizosphere soils resulted much lower microbial biomass values in the polluted soils, which suggests disturbance in the organic matter transformation dynamics. A significant increase in acid phosphomonoesterase activity was determined in the soil due to the pollution. The phosphatase enzyme production of living organisms may be stimulated by the measured higher moisture content and significantly lower LE-soluble phosphorus content of the polluted soil samples. The correlation established between soil water content and phosphatase activity was positive (r = +0.85), while that between LE-P content and phosphatase activity was negative (r = -0.69). The most important stimulating effect was attributable to the lower available phosphorus content, resulting from the heavy metal (Pb, Zn) content of polluted soil. Both measured biological parameters therefore were suitable for indicating soil pollution, but the change was adverse, the biomass decreased, while phosphatase activity increased. Microbial biomass and phosphatase activity were not correlated, indicating the different account of ecological factors that alter the biological properties of a soil.
Abstract
A frequently used method in determining the radium concentration of water is the radon emanation method. When radon gas is transferred to the Lucas-cell usually CaCl2 is used to remove the water traces. When we measured the background of the system using ultra clear distilled water the results were astonishing. The detailed investigation has shown that the unwanted radon originated from the CaCl2, contained about 1000 Bq/kg of 226Ra. Depending on the time interval between two measurement, the radon deriving from the CaCl2 disturbed the measurements.
Abstract
The radiation dose of workers and patients resulting from inhaling radon and through the consumption of spring waters was examined in the hospital near the Héviz lake in Hungary. The radiation dose originating from radon was 2.15–3.95 mSv·y−1 concerning workers at the spa. The radiation dose originating from radon in the case of those regularly taking a bath was an average of 0.75 mSv·y−1. Due to the limited duration of treatments a bound effective dose of maximum 100 µSv·y−1 may originate from radon and inhaling radon, while a maximum of 1.4 µSv·y−1 may originate from ingestion of 222Rn, 226Ra, 234U and 238U radionuclides.
Abstract
Radon can accumulate in underground areas such as show caves. Repairmen and tourist guides working in such caves may thus be exposed to significant radiation doses. Therefore, it is necessary to measure the radon concentration to estimate the exact radiation dose caused by radon. Considering that the radon concentration in caves usually shows significant seasonal fluctuations, the monthly change of radon concentration was studied for 1 year in nine show caves opened to the public in Hungary. Despite the fact that all of the caves were formed in karst rocks, the annual average radon concentration levels were rather different between each other (541–8287 Bq m−3). The significant monthly fluctuation of the radon concentration indicates that the annual average radon concentration in caves can only be accurately obtained by year-long measurements.
