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  • Author or Editor: Yu. Sapozhnikov x
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Abstract  

The international community presently lacks the ability to determine the quality and credibility of environmental measurements that is required to make sound decisions in matters related to international security, public health, and investment-related considerations. The ultimate goal of the work described in this article is to develop a credible information base including measurement capability for determination of environmental contamination and the potential for proliferation of material components of chemical or nuclear weapons. This study compared the accuracy obtained by six Russian and six U.S. laboratories for samples representative of classes of trace metals, dioxin-furans, and radioactive substances. The results obtained in this work indicate that current estimates for laboratory accuracy are likely overly optimistic. The weaknesses discovered by this prototype U.S. — Russia, study also exist within the broader international community of laboratories. Further work is proposed to address the urgent need for the international community to improve performance evaluations for analytical measurements.

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Abstract  

The interaction of short-lived Rn-daughter products /SLDP/, viz.214Pb and214Bi dissolved in sea-water with Fe/III/ hydroxide colloids followed by flotation of combined Fe-SLDP particles at the sea-air interface subsequently generating marine aerosols enriched in214Bi and214Pb have been studied under laboratory conditions. Rate constants for attachment of214Bi and214Pb to dispersed Fe/III/ colloids in the sea water are found to be 3.7×10–4 min–1 litre [g/Fe/]–1 and 2.4×10–4 min–1 litre [g/Fe/]–1, resp., /20°C/ over the concentration range of iron /III/ from 8 to 120 g liter–1. The suggested mechanism of colloid flotation and aerosol generation might be responsible for some peculiarities of SLDP distribution in the lower marine atmosphere.

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Abstract  

Fourteen samples of wastes from algal plants were tested for possible analytical and/or technological use for90Sr and137Cs extraction from natural waters. Sorption experiments were carried out in static and dynanic conditions. It was noted that the examined sorbents posses high affinity for Sr2+. The sorption capacity reached the value of 4.72·10−3 mole/g. Simple and express analytical procedures for90Sr determination were developed and tested in the Dnieper estuary region.

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Abstract  

Determination of lead-210 in bottom sediments is applied for evaluation of sedimentation rates and sediments ages by concentration profiles of disequilibrated lead-210 from atmospheric sources. Advences in low level liquid scintillation spectrometry (LS) fitted for natural radioactivity measurements, permit to combine the possibility of immediate bismuth-210 separation with its radioactivity registration using LS spectrometer Quantulus (LKB-1220, Wallak, Finland). The method was tested on bottom sediment samples from Baltic Sea shelf, collected during the 76th cruise of RV Academician S. Vavilov. The proposed method of separation, purification and chemical yield determination is characterized by simplicity, rapidity and may be used in routine analysis.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
E. Shumilin
,
St. Kalmykov
,
D. Sapozhnikov
,
E. Nava-Sánchez
,
D. Gorsline
,
L. Godinez-Orta
,
Yu. Sapozhnikov
,
O. Holguin Quiñones
, and
A. Rodriguez Castaneda

Abstract  

The vertical distribution of K, Rb, Cs, Ca, Sr, Ba, Fe, Cr, Co, Ni, Zn, Sc, Zr, Sb, Se and As was studied by means of instrumental neutron activation analysis in four sediment cores collected from the eastern shelf of tectonically active Baja California peninsula accompanied by 210Pb age-dating. 210Pb analysis was performed by extraction chromatography with measuring the ingrowing daughter 210Bi radioactivity by liquid-scintillation spectrometry. It was found that concentration variations of Se, As, Sb, Zr and Zn are probably controlled by the intensity and composition of the material supplied from the drainage basin constituted by volcanic and sedimentary rocks.

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Summary  

The properties of bentonite to remove radionuclides from aqueous solutions were studied as a function of pH and ionic strength. The sorption of cesium is due to ion-exchange while in the case of actinides, sorption is defined by surface complexation at neutral and slightly alkaline conditions and by both mechanisms at acidic pH. Due to the presence of Fe(II), actinides are reduced to low valence states that defines their strong retention onto bentonite and low solubilities. The solubility of both neptunium and plutonium were in the order of 2 . 10-8-4 . 10-8M with amorphous An(IV)O2 as solubility limiting phases.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
N. St. Kalmykov
,
A. Arhipov
,
A. Abramov
,
N. Ivanova
,
B. Iofa
,
O. Pronina
,
Yu. Sapozhnikov
, and
A. Anisimov

Abstract  

Liquid-liquid extraction of several cations by some oxa-tia- and tia-crown ethers was studied. Sr(II), Pb(II) and Ag(I) were taken as hard, borderline and soft Lewis acids, respectively. Trace amounts of210Sr and110mAg were used as chemical yield monitors. The results were explained by the Pearson theory. Some of the examined compounds posses high affinity towards Ag(I) and Pb(II) extraction. The distribution coefficent for Ag(I) reached the value of 140.

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