S. S. Pavlov

Experimental substantiation of the possibility of developing selenium- and iodine-containing pharmaceuticals based on blue–green algae Spirulina platensis

The great potential of using blue-green algae Spirulina platensis as a matrix for the production of selenium- and iodine-containing pharmaceuticals is shown experimentally. The background levels of 31 major, minor and trace elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni (using (n,p) reaction), As, Br, Zn, Rb, Mo, Ag, Sb, I, Ba, Sm, Tb, Tm, Hf, Ta, W, Au, Hg, Th) in S. platensis biomass were determined by means of epithermal neutron activation analysis. The dependence of selenium and iodine accumulation in spirulina biomass on a nutrient medium loading of the above elements was characterized. To demonstrate the possibilities of determining toxic element intake by spirulina biomass, mercury was selected. The technological parameters for production of iodinated treatment-and-prophylactic pills are developed.

Trends of atmospheric deposition of trace elements in Macedonia studied by the moss biomonitoring technique

In 2002 and 2005 the moss biomonitoring technique was applied to air pollution studies in the Republic of Macedonia in the framework of the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops under the auspices of the United Nations Economic Commission for Europe (UNECE-ICP Vegetation) Convention on Long-Range Transboundary Air Pollution (LRTAP). In August 2005 samples of the terrestrial mosses Homolothecium lutescens and Hypnum cupressiforme were collected at 72 sites evenly distributed over the territory of the country, in accordance with the sampling strategy of the European moss survey programme. A total of 41 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, Mo, Cd, Sb, I, Cs, Ba, La, Ce, Sm, Eu, Tb, Dy Hf, Ta, W, Hg, Pb, Th, and U) were determined by instrumental epithermal neutron activation analysis and atomic absorption spectrometry. Principal component analysis was used to identify and characterize different pollution sources. Distributional maps were prepared to point out the regions most affected by pollution and to relate this to known sources of contamination. A few areas, as in 2002, are experiencing particular environmental stress: Veles, Skopje, Tetovo, Radoviš and Kavadarci-Negotino, whereas the agricultural regions in the south, south-west, and south-east show median European values for most elements of mainly pollution origin. A significant increase in the content of Ni is noticed in the 2005 moss survey compared with 2002, due to the increased production of the ferro-nickel smelter in Kavadarci. A higher content of Cd, Hg, and Pb in 2005 relative to 2002 can be explained by pollution from the lead-zinc smelter in Veles, as well as the pollution that comes from the open slag waste dump of this smelter. Protection activities on the dump of slag from the former ferrochromium smelter located near Tetovo resulted in a lower content of Cr in the 2005 moss survey.

Atmospheric deposition of heavy metals in northern Serbia and Bosnia-Herzegovina studied by the moss biomonitoring, neutron activation analysis and GIS technology

The results on atmospheric deposition of heavy metals and other trace elements using the moss biomonitoring technique in the northern part of Serbia and some areas of Bosnia-Herzegovina are presented. Samples of Hypnum cupressiforme along with some other moss types were collected at 92 sites during the summer of 2000. A total of 44 elements were determined by INAA using epithermal neutrons. High values of Cl and V content in the moss samples at certain areas are suspected to be associated with fires in oil refineries damaged during the 1999 NATO military action.

ENAA studies of chromium uptake by Arthrobacter oxydans

To study chromium uptake by Arthrobacter oxydans [Cr(VI)-reducing bacteria isolated from Columbia basalt rocks, USA] the instrumental epithermal neutron activation analysis (ENAA) was applied. It was established that chromate accumulation is dose-dependent and it is most intensive in the interval of Cr(VI) concentrations (10-50 mg/l). At lower concentrations of Cr(VI) (up to 50 mg/l) the most intensive formation of Cr(V) was found using ESR method. Besides, it was established that reduction from Cr(VI) to Cr(V) is a faster process than the uptake of Cr(VI). According to ENAA measurements, in contrast to Cr(VI), Cr(III) is not accumulated in Arthrobacter oxydanscells up to concentrations of 200 mg/l. Using epithermal neutron activation analysis the background levels of 17 major, minor and trace elements were determined in Arthrobacter oxydans.

Automation system for neutron activation analysis at the reactor IBR-2, Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna, Russia

The present status of development of software packages and equipment designed for automation of NAA at the reactor IBR-2 of FLNP, JINR, Dubna, RF, is described. The NAA database, construction of sample changers and software for automation of spectra measurement and calculation of concentrations are presented. Automation of QC procedures is integrated in the software developed. Details of the design are shown.

Automation of the quantitative determination of elemental content in samples using neutron activation analysis on the IBR-2 reactor at the frank laboratory for neutron physics, joint institute for nuclear research

Software for the automated quantitative determination of element concentrations in samples is described. This software is used in neutron activation analysis (NAA) at the IBR-2 reactor of the Frank Laboratory for Neutron Physics, Joint Institute for Nuclear Research (FLNP JINR).

Automation system for measurement of gamma-ray spectra of induced activity for multi-element high volume neutron activation analysis at the reactor IBR-2 of Frank Laboratory of Neutron Physics at the joint institute for nuclear research

The automation system for measurement of induced activity of gamma-ray spectra for multi-element high volume neutron activation analysis (NAA) was designed, developed and implemented at the reactor IBR-2 at the Frank Laboratory of Neutron Physics. The system consists of three devices of automatic sample changers for three Canberra HPGe detector-based gamma spectrometry systems. Each sample changer consists of two-axis of linear positioning module M202A by DriveSet company and disk with 45 slots for containers with samples. Control of automatic sample changer is performed by the Xemo S360U controller by Systec company. Positioning accuracy can reach 0.1 mm. Special software performs automatic changing of samples and measurement of gamma spectra at constant interaction with the NAA database.

Nuclear and related analytical techniques in ecology: Impact of geoecological factors on the balance of trace elements in the human organism

Current capabilities of the nuclear and related analytical techniques: neutron activation analysis, X-ray fluorescent analysis, and atomic adsorption spectrometry—are used to carry out multielement analysis of a wide range of foodstuffs and drinking water in various regions of Russia. The results of a more than 20-year-long collaboration of the Geological Institute, Russian Academy of Sciences, and the Neutron Activation Analysis and Applied Research Sector, Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, in this field are presented. It is shown that the trace element content of agricultural products depends on the ecological and geochemical conditions in a particular region. A possibility of lettuce and spinach variety determination with respect to Cd and Pb contamination of the soil is demonstrated in the experiment with artificially produced soil contamination. Principles that may underlie accumulation of heavy metals and toxic elements by basidiomycetes are determined. Out of a great deal of human diets in use, the six most typical ones are selected and the intake of macro- and micronutrients from these diets by a human is evaluated. The effect produced on the human organism by the basic elements intake with the food and possible risks are discussed. Dependence of the trace element content of the drinking water on the ecological and geochemical conditions is investigated in three regions of Russia. It is shown that the quality of drinking water critically depends on the condition of the water supply system.

Neutron activation analysis for studying Cr uptake in the blue-green microalga Spirulina platensis

Exposure of Spirulina platensis cells to Cr(III) and Cr(VI) showed that unlike other organisms this blue-green alga demonstrates a protective ability against Cr(VI). In laboratory experiments, the less toxic Cr(III) was absorbed much more readily than the more toxic Cr(VI). Colorimetric and EPR tests indicated that higher oxidation states of Cr are not formed following the accumulation of Cr(III) in Spirulina platensis cells. Control of the protein content and cytological study of the alga cells indicated that Spirulina platensis retains its natural properties after exposure to significant amounts of Cr(III).

Nuclear-physical analysis methods in medical geology: Assessment of the impact of environmental factors on human health

The procedure for geomedical studies is outlined, and the niche occupied by the nuclear-physical analysis methods in these studies is pointed out. The necessity of construction of an efficient complex of the most modern analytical methods is demonstrated. The metrological parameters of methods applied in the analysis of natural environments and biological materials are evaluated. The current state of pollution of natural environments with heavy and toxic metals is characterized in two specific industrial hubs: the towns of Gus-Khrustalny and Podolsk. The levels of pollution of diagnostic biological materials (hair and blood) from children living in various urban districts are studied in the light of specific features of the manufacturing industry in these towns and the life environment of child population. The results of studies focused on evaluating the effect of environment on the health of child population are detailed. The actual damage to child health, their neuropsychic development and behavior, and the effect of socioeconomic factors are determined. Preventive problems among the child population exposed to lead and other toxic metals are evaluated, and ways to solve them are proposed. A system of early diagnosis and preventive measures for the mitigation of adverse effect of toxic metals (Pb, Cu, Mn, Zn, Cr, Ni, As, etc.) on the neuropsychic development of children is developed based on an actual ecogeochemical estimation of the state of the region under study.