Concentrations of natural radionuclides in imported zirconium minerals

The natural radioactivity in imported zircon samples used as glaze for ceramic tiles in the ceramics industry has been presented in this paper. The measurements were made by gamma spectrometry with a high purity germanium detector. The average activity concentrations of 238U and 232Th determined in the measured samples (3250 Bq/kg, and 556 Bq/kg, respectively) are much higher than the concentrations found in the Earth’s crust. The activity concentration of 226Ra is also high in all analyzed samples, while 40K was not detected. The gamma index, I, the external hazard index, Hex, the internal hazard index, Hin, and the radium equivalent activity, Raeq, were calculated. Due to relatively high activity concentration level of uranium in imported zircon samples, specific regulations are necessary for zircon compound used in ceramic industry. It can be concluded that the investigated samples can be used as the component of ceramic glaze in the concentrations not above 3%

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

Raspodela pristupačnih sadržaja mikroelemenata po dubini kultivisanog zemljišta

This paper presents a study of the profile distribution of available micronutrients Fe, Mn, Cu and Zn and radionuclide 137Cs in cultivated soil at the experimental field 'Radmilovac' (property of Agricultural Faculty, Belgrade University) in the vicinity of Vinča Institute of Nuclear Sciences. The soil belongs to the anthrosol class of anthropogenic soils according to FAO (2006). At first, the deep plowing was performed while preparing soil for planting peach trees followed by cultivation of soil for 12 years. All agricultural treatments at the experimental field ceased for three years. After that period, soil sampling was carried out. Contents of DTPA-extracted Fe, Mn, Cu and Zn were in the range of (mg kg-1): 5.8-41.6; 9.2-34.2; 1-7.6 and 0.2-1.3, respectively. Detected activity concentration (Bq kg-1) for 137Cs ranged from 1.8 to 35. It was noticed that distribution patterns of 137Cs radionuclide and available Cu and Zn along soil depth were very similar and they were analyzed by simple linear regression; mutual affinity for the soil organic matter might affect their distribution in soil. Contents of available Fe and Mn exhibited different, more constant distribution within a soil horizon.U ovom radu ispitivana je raspodela sadržaja pristupačnih mikroelemenata Fe, Mn, Cu i Zn i koncentracije aktivnosti proizvedenog radionuklida 137Cs u profilima zemljišta (dubine 080 cm) sakupljenih sa voćnjaka pod zasadom breskvi na oglednom školskom poljoprivrednom dobru 'Radmilovac' (Poljoprivredni fakultet, Univerzitet u Beogradu) u neposrednoj blizini Instituta za nuklearne nauke 'Vinča'. Zemljište pripada klasi antrosol antropogenih zemljišta prema međunarodnoj FAO (2006) klasifikaciji. Priprema zemljišta za sadnju bresaka izvršena je rigolovanjem, posle čega je usledila 12 godina duga nega voćnjaka. Uzorkovanje zemljišta izvršeno je tri godine nakon prestanka svih poljoprivrednih tretmana zemljišta na oglednom polju. Sadržaji pristupačnih mikroelemenata Fe, Mn, Cu i Zn (dobijeni ekstrakcijom sa rastvorom 0,005 M DTPA) nalazili su se u opsegu (mg kg-1): 5,841,6; 9,234,2; 17,6 odnosno 0,21,3. Detektovana koncentracija aktivnosti 137Cs u zemljištu (merena metodom gama-spektrometrije korišćenjem koaksijalnog HPGe-detektora) nalazila se u intervalu (Bq kg-1): 1,835. Uočeno je da su obrasci distribucije po dubini profila pristupačnih oblika Cu i Zn i radionuklida 137Cs bili veoma slični, a rezultati proste linearne regresione analize su pokazali da je uzajamni afinitet prema organskoj materiji zemljišta mogao da utiče na takvu njihovu distribuciju. Sadržaji pristupačnih mikroelemenata Fe i Mn, pokazali su da imaju drugačiju, uniformniju distribuciju po dubini ispitivanih profila zemljišta

Natural and artificial (90Sr) radionuclides in some carbonated mineral waters used in Serbia

A radiological characterization of 7 different carbonated mineral water samples collected in the local supermarkets in the area of Belgrade (produced in Serbia) was carried out. Analysis included determination of gross alpha and gross beta activities. The obtained results showed that the natural activity concentrations of alpha and beta emitting radionuclides in carbonated mineral water samples were within World Health Organization recommended levels, except for the Heba Strong and Kiseljak samples where the beta activity exceeds 1 Bq/L. For these two water samples gamma spectrometry analysis was performed as well as determination of 90Sr by oxalic method. The instrumentation used to count the gross alpha and gross beta activities, as well as for 90Sr, was a/b low level proportional counter Thermo Eberline FHT 770 T. Gamma spectrometric measurements were performed using a HPGe Canberra detector with a counting efficiency of 20%. The annual effective dose equivalent due to ingestion of investigated waters was calculated for age group >17, and obtained values are lower than 0.1 mSv recommended reference level. Finally, a comparison of the investigated waters with worldwide data was made. [Projekat Ministarstva nauke Republike Srbije, br. III43009

Uticaj hroničnog trovanja olovom na aktivnost nekih enzima u krvnom serumu pacova

In this paper, the influence of chronic lead intoxication on the activity of serum enzymes aspartate and alanine aminotransferases (AST and ALT) and alkaline phosphatase (ALP) was examined. The experiment was performed on 130 adult female DA rats and 80 young rats. Rats were treated by lead-acetate 100 and 30 mg Pb per kg body weight for 10, 20, 30, 40, 50 and 60 days. Young rats (offspring of studied female rats) were treated with lead only through the placenta and mother's milk. The activities of serum AST, ALT and ALP were determined spectrophotomerically by IFCC method. The activity of examined serum enzymes was significantly increased in conditions of chronic lead intoxication in female rats and their offspring in relation to the control group. The activity of serum AST, ALT and ALP was in a positive correlation with the time of intoxication. There were no significant differences between the activities of enzymes AST and ALT in the serum and the amount of lead. The activity of ALP was significantly higher in serum of rats treated with higher amounts of lead. Increased AST, ALT and ALP activity in serum is most likely the consequence of lead hepatotoxicity.U ovom radu su prikazani rezultati ispitivanja uticaja hroničnog trovanja olovom na aktivnost enzima aspartat i alanin aminotransferaze (AST i ALT) kao i alkalne fosfataze (ALP) u krvnom serumu pacova. Eksperiment je izveden na 130 ženki pacova i njihovih 80 mladunaca. Ženke su tretirane olovo-acetatom oralno putem pijaće vode u dve doze-100 i 30 mg/kg TM dnevno u trajanju od 10,20,30, 40, 50 i 60 dana, dok su njihovi mladunci olovo primali samo preko placente i putem mleka. Nakon žrtvovanja, od životinja je uzimana krv i u krvnom serumu je spektrofotometrijski, na automatskom analizatoru Hitachi 911, određivana aktivnost enzima AST, ALT i ALR Dobijeni rezultati su ukazali da hronično trovanje olovom ima za posledicu značajno povećanje aktivnosti enzima AST, ALT i ALP u krvnom serumu ženki pacova, pri čemu se aktivnost navedenih enzima linearno povećavala sa povećanjem vremena intoksikacije. Nisu zapažene značajne razlike u aktivnosti enzima AST i ALT u odnosu na primenjenu dozu olova, dok je u slučaju ALP ustanovljeno da veća doza olova ima za posledicu značajnije povećanje aktivnosti ovog enzima u krvnom serumu. U mladunaca ženki koje su tokom trudnoće i laktacije primale olovo, takođe je ustanovljeno značajno povećanje aktivnosti navedenih enzima u krvnom serumu u odnosu na kontrolnu grupu. Nisu ustanovljene značajne razlike u aktivnosti AST, ALT i ALP u serumu mladunaca u pogledu doze olova koje su njihove majke primale. Povećanje aktivnosti enzima AST, ALT i ALP u krvnom serumu ženki i mladunaca je najverovatnije posledica hepatotoksičnog dejstva olova udruženog sa intrahepatičkom holestazom

Radioactivity measurements in soils surrounding four coal-fired power plants in Serbia by gamma-ray spectrometry and estimated dose

The study of spatial distribution of activity concentration of U-238, Ra-226, (210)pb, Th-232, K-40 and Cs-237 radionuclides in the surface soil samples (n = 42) collected in the vicinity of four coal-fired power plants in Serbia is presented. Radioactivity measurements in soils performed by gamma-ray spectrometry showed values [Bqkg(-1)] in the range: 15-117 for U-238, 21-115 for Ra-226, 33-65 for (210)pb, 20-69 for Th-232, 324-736 for K-40, and 2-59 for Cs-137. Surface soil radioactivity that could have resulted from deposition of radionuclides from airborne discharges or resuspension of ash from disposal sites showed no enhanced levels. It was found that variation of soil textural properties, pH values, and carbonate content influenced activity levels of natural radionuclides while radiocesium activities were associated with soil organic matter content. Modification of some soil properties was observed in the immediate vicinity ( lt 1 km) of power plants where the soil was more alkaline with coarser particles (0.2-0.05 mm) and carbonates accumulated. Calculated average values of the absorbed gamma dose rate and annual external effective dose originating from the terrestrial radionudides were 69.4 nGy/h and 0.085 mSv, respectively

Microwave-Assisted Synthesis of N-Doped Carbon Quantum Dots for the Photocatalytic Removal of Methylene Blue From Wastewater

Wastewater treatment is an emerging problem in the industrialized world. The development of new semiconducting materials with the potential to be used in photocatalysis is the focus of the scientific community. Here, we present the synthesis of N-doped carbon quantum dots (N- CQDs) using microwave radiation. N-CQDs were synthesized by irradiation of glucose solution in the presence of ammonia hydroxide as a nitrogen doping agent at low temperature (100 °C), low applied microwave power (100 and 200 W), and for a short period of time (60 s). The possible application of N-CQDs as a catalyst for photocatalytic degradation of Methylene Blue (MB) dye under blue light, green light, red light, and daylight was investigated. The highest values of MB degradation were observed for the samples exposed to red light with a maximum of 58.8 % for N-CQDs sample prepared at the reactor power of 200 W exposed to red light for 2 h.26th International Symposium on Analytical and Environmental Problems : Proceedings; November 23-24, 2020; Szeged, Hungary

Radioaktivnost u životnoj sredini južne Srbije na lokacijama na kojima je korišten osiromašeni uran

In the 1999 bombing of the Federal Republic of Yugoslavia, NATO forces used ammunition containing depleted uranium. The cleaning of depleted uranium that followed was performed in southern Serbia by the Vinča Institute of Nuclear Sciences between 2002 and 2007 at the locations of Pljačkovica, Borovac, Bratoselce, and Reljan. This paper presents detailed results of radioactivity monitoring four years after cleaning (2011), which included the determination of gamma emitters in soil, water, and plant samples, as well as gross alpha and beta activities in water samples. The gamma spectrometry results showed the presence of natural radionuclides 226Ra, 232Th, 40K, 235U, 238U, and the produced radionuclide 137Cs (from the Chernobyl accident). In order to evaluate the radiological hazard from soil, the radium equivalent activity, the gamma dose rate, the external hazard index, and the annual effective dose were calculated. Considering that a significant number of people inhabit the studied locations, the periodical monitoring of radionuclide content is vital.U napadu na Saveznu Republiku Jugoslaviju 1999. godine NATO-ove su snage koristile municiju s osiromašenim uranom. Od 2002. do 2007. Laboratorij za zaštitu od zračenja i zaštitu životne sredine Instituta Vinča proveo je akciju čišćenja osiromašenog urana na lokacijama Pljačkovica, Borovac, Bratoselce i Reljan. U ovom se radu iznose detaljni rezultati praćenja radioaktivnosti u južnoj Srbiji četiri godine nakon spomenute akcije čišćenja (2011), koji uključuje određivanje gama zračenja u uzorcima zemljišta, vode i biljki te određivanje ukupne alfa i beta aktivnosti u uzorcima vode. Rezultati gama spektrometrije pokazali su prisutnost prirodnih radionuklida: 226Ra, 232Th, 40K, 235U, 238U i proizvedenog radionuklida 137Cs. Za procjenu radijacijskog rizika iz zemljišta izračunati su ekvivalent radija, brzina apsorbirane doze gama zračenja, indeks radijacijskog rizika uslijed vanjskog izlaganja i efektivna doza zračenja. Imajući u vidu da na ispitivanim područjima živi znatan broj ljudi, iznimno je važno da se ondje periodično prati sadržaj radionuklida

Microwave Synthesis of N‒CQDs: Effect of Wavelength on Degradation of Organic Pollution in Water

Industries today realis high amounts of different hazards into the environment without any pre– treatment, which is why the remediation from organic pollution still represents one of the most important issues in waste water treatment. Organic dyes from textile industry are one of the extremely geno‒toxic and cyto‒toxic pollutants. Thus, finding the appropriate photocatalyst for the treatment of contaminated water under sunlight is still a challenging work from economical and green chemistry approach. Here we present a microwave assisted synthesis of nitrogen doped carbon quantum dots with high efficiency in degradation of Rose Bengal organic dye from water under visible, blue, green and red light irradiation in batch system. The effect of microwave irradiation power and time on size and photocatalytic activity of synthesized dots were also investigated.26th International Symposium on Analytical and Environmental Problems : Proceedings; November 23-24, 2020; Szeged, Hungary

Dynamics of FitzHugh-Nagumo excitable systems with delayed coupling

Small lattices of $N$ nearest neighbor coupled excitable FitzHugh-Nagumo systems, with time-delayed coupling are studied, and compared with systems of FitzHugh-Nagumo oscillators with the same delayed coupling. Bifurcations of equilibria in N=2 case are studied analytically, and it is then numerically confirmed that the same bifurcations are relevant for the dynamics in the case $N>2$. Bifurcations found include inverse and direct Hopf and fold limit cycle bifurcations. Typical dynamics for different small time-lags and coupling intensities could be excitable with a single globally stable equilibrium, asymptotic oscillatory with symmetric limit cycle, bi-stable with stable equilibrium and a symmetric limit cycle, and again coherent oscillatory but non-symmetric and phase-shifted. For an intermediate range of time-lags inverse sub-critical Hopf and fold limit cycle bifurcations lead to the phenomenon of oscillator death. The phenomenon does not occur in the case of FitzHugh-Nagumo oscillators with the same type of coupling.Comment: accepted by Phys.Rev.