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  • Author or Editor: M. Frontasyeva x
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Abstract  

Epithermal neutron activation analysis is shown to be a powerful technique for the simultaneous determination of chlorine, bromine and iodine in organic-rich soils. Examples are shown from a transect study in northern Norway where samples of surface soil were collected at distances of 0–300 km from the coastline. All three elements decreased exponentially as a function of distance from the ocean, strongly indicating that atmospheric supply from the marine environment is the predominant source of these elements in the soil. The Cl/Br and Br/I ratios also showed a regular change with distance from the ocean, and hypotheses for this behavior are offered.

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Abstract  

INAA is known to be a powerful technique for the simultaneous determination of chlorine, bromine and iodine. In this paper INAA using epithermal neutrons is shown to be particularly useful to elucidate marine gradients of these elements. Examples are from a transect study in northern Norway where samples of the feather moss Hylocomium splendens were collected at distances of 0-300 km from the coastline. All three elements decrease exponentially as a function of distance from the ocean in the moss samples, strongly indicating that the atmospheric supply from the marine environment is the predominant source of these elements to the terrestrial ecosystem. It is suggested that environmental studies of halogens in general and iodine in particular is a promising future area of application for INAA, when employing epithermal neutrons.

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Summary  

In ombrotrophic bogs the surface peat layer is supplied with chemical substances only from the atmosphere. Therefore, peat cores from these bogs can be used to study temporal trends in atmospheric deposition of pollutants. In this work epithermal neutron activation analysis was applied for the first time to study the distribution of 35 elements in peat profiles from ombrotrophic bogs. The selected samples were from Finnmark county in northern Norway, one pristine site far from any local pollution source, and the other samples from strongly affected by long-term operation of a Russian copper-nickel smelters located close to the border. The elements are classified with respect to their behavior in the uppermost 40 cm of the peat, and similarities and differences between the two profiles are discussed. As compared with other more commonly used analytical techniques based on acid decomposition of the sample, ENAA has the advantage of providing the total concentrations of the elements.

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Abstract  

Experience in application of radioanalytical methods, including NAA, at the IBR-2 pulsed fast reactor is reviewed. Details of the instruments dedicated to the neutron activation analysis and radiography studies are reported. Applications of resonance neutrons to environmental control, to analysis of geological samples in oil extraction regions, to testing the quality of food products, and to the investigation of high-purity materials to solve nuclear physics problems, are exemplified. Work to use isotopic neutron sources for an analysis for nitrogen in natural and synthetic materials is being carried out.

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Abstract  

For the first time the moss biomonitoring technique has been applied to air pollution monitoring in Central Russia (Tula region). INAA at the IBR-2 reactor has made it possible to determine the content of 33 elements in mosses collected at 83 sampling site. In addition to NAA, flame AAS (atomic absorption spectrometry) was applied to determine the content of Cd, Cu and Pb. Factor analysis was applied to determine possible sources of trace element deposition in Tula mosses. The geographical distribution of factor scores and some element distribution maps over the investigated territory are presented.

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Abstract  

Experience in applying conventional and epithermal neutron activation analysis for some challenging areas of life sciences and material science is reviewed. For more than 30 years of its operation the radioanalytical complex REGATA at the IBR-2 reactor in Dubna has become a source of analytical data for the environmental studies, marine geology, biotechnology and medicine, technological process of diamond and boron nitride synthesis, archaeology, nanomaterials, etc. In spite of competing non-nuclear analytical techniques (AAS, ICP-ES, ICP-MS, etc.), the reactor neutron activation analysis (NAA) as a primary (ratio) method continues to be the most powerful multielement analytical technique providing quantification of trace elements at ultralow levels. Combined with modern statistical data treatment of large arrays of data, GIS (geographic information system) technologies, electron scanning microscopy, tomography, and others, NAA serves to obtain actual, practical results resumed in the review. The perspectives of using the upgraded reactor IBR-2M for analytical investigations are discussed.

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Abstract  

Instrumental activation analysis (INAA) based on irradiations in a nuclear reactor with particularly high relative fluxes of resonance and fast neutrons has been shown to open new possibilities for multi-element surveys of mosses used as monitors of atmospheric deposition. Comparison is made with data obtained by inductively coupled plasma-mass spectrometry (ICP-MS) and conventional INAA. Data for 15 elements not previously investigated in routine moss studies are presented, e.g., Zr, Sn, Hf, Ta, W, Au, Th, and the rare earth elements Ce, Nd, Eu, Gd, Tb, Tm, Yb, Lu. Other elements particularly well determined by this approach are Sc, Co, As, Ag, Sb, Cs, La, Sm, Th, and the non-metallic trace elements Se, Br, and I. Advantages and drawbacks with the high fast neutron component are discussed.

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Abstract  

The results of activation studies of concrete ingredients for shielding structures of nuclear installations in the aspect of their decommissioning are given. It is shown that for the long-lived induced radioactivity of construction mineral materials irradiated for 30 years and cooled for more than one year such radionuclides as calcium, iron, cobalt, caesium and europium are responsible. Elemental content of the binding agent and raw material components for their production is obtained by neutron activation analysis. The results show that the type of the binding agent influences to a great extent the concrete shielding activity. The concentration of the above mentioned elements should be taken into account even at the stage of nuclear power plants design. It would allow one to make a prognosis on the volume and radioactivity of wastes as on the radioactivity effect felt by the staff engaged in the decommissioning.

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Abstract  

An intercomparison of data obtained for a moss reference material (Hylocomium splendens) used as biomonitor of atmospheric deposition by different multi-element techniques is presented. In total 43 elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, Ag, Sn, Sb, I, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Tm, Yb, Lu, Hf, Ta, W, Au, Th, U) were determined using inductively coupled plasma-mass spectrometry (ICP-MS), conventional instrumental neutron activation analysis (INAA), epithermal neutron activation analysis (ENAA) and as well as shorttime neutron activation analysis without and with a6LiD-converter. Advantages and drawbacks of each method are discussed. The introduction of moss reference materials for atmospheric multi-element deposition studies involving nuclear analytical techniques is strongly recommended.

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Abstract  

The heavy metal pollution in the South Ural region was studied by nuclear and related techniques. The feasibility of the moss technique to study the regional air pollution is also presented.

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