Physicochemical properties and biological activity of the water depleted of heavy isotopes

Data on physicochemical properties of the light water (deuterium concentration is reduced to the ratio D/H = 4 ppm and that of the isotope of oxygen 18—to the ratio ¹⁸O/¹⁶O = 750 ppm) have been obtained. They include the melting and boiling points, kinematic viscosity, density, the spin-spin proton relaxation time, self-diffusion coefficients, and the small-angle laser light scattering. It was found out that the biological activity of the light water was determined by the mechanisms different from the ligand-induced toxic effects. An explanation was proposed for the detected significant changes of the light water as compared with the high-resistivity water having geochemically ordinary isotope composition. This explanation was based on the mechanism of formation of supramolecular density inhomogeneities in water representing the deuterium-stabilized heterophase clusters.     

The concept of choosing a list of indices and their regulatory values for determination of hygienic requirements and control over the drinking water quality in Ukraine

The paper presents new conceptual approaches to establishing indices for the quality of physiologically wholesome drinking water for the population based on the analysis of the composition of surface and underground sources of water supply in Ukraine. We have proposed ecological regulations for the quality of Ukraine’s surface waters as a basis for the choice of quality values of these indices. These regulations provide effectively for the absence of anthropogenic contamination of natural sources of water supply. We have also considered present-day approaches to regulating maximum admissible concentrations (MAC) of drinking water impurities during its conditioning at the stations of centralized water supply. We have provided qualitative MAC values of water impurities, which may be recommended taking into account technological and economic possibilities.     

Verification of existing regulatory documents when assessing the quality of sources of centralized drinking water supply

The article has considered versions for classification of the water quality of surface drinking water sources. The article has demonstrated the verification results of a draft new state standard using as an example assessments of the quality of a surface sources of centralized drinking water supply. A comparative analysis has been conducted for its application concurrently with existing regulatory documents.     

Coprecipitation of neptunium(IV) and plutonium(IV) with hydrolyzed iron(III) in carbonate solutions

In regeneration of Np(IV)-and Pu(IV)-containing recycled solvent by treatment with aqueous sodium carbonate contaminated with iron, some portion of Np(IV) and Pu(IV) coprecipitates with hydrolyzed iron. The degree of coprecipitation of Np and Pu depends on both the iron and sodium carbonate concentrations. The presence of n-dibutyl hydrogen phosphate in the recycled solvent before its regeneration does not noticeably affect the coprecipitation of Np and Pu. The possible mechanisms of coprecipitation of actinides with hydrolyzed iron in carbonate solutions are discussed.     

Manganese nitrides

Conclusions An investigation was carried out into the kinetics of the process of formation of manganese nitrides in nitrogen and ammonia streams. It was established that the rate of formation of manganese nitrides is higher in ammonia than in nitrogen. The kinetic parameters of manganese nitride formation were calculated.It is shown that in nitrogen the only manganese nitride that can be synthesized in the pure form is Mn_N. In ammonia, depending on the temperature and duration of the nitriding process, it is possible to obtain Mn_N, Mn₂N, and Mn₃N₂ in the pure form, free from any other phases.A study was made of the chemical stability of manganese nitrides of compositions Mn₄N and Mn₃N₂ in water and in concentrated and dilute mineral acids. It was established that these two nitrides are stable in water. In mineral acids they dissolve, the rate of dissolution being higher in concentrated than in dilute acids. In nitric acid Mn₄N and Mn₃N₂ decompose with the liberation of part of the nitrogen in molecular form.Translated from Poroshkovaya Metallurgiya, No. 3(171), pp. 65–70, March, 1977.