Vol 64, No 7 (2019)
- Year: 2019
- Articles: 7
- URL: https://journals.eco-vector.com/0016-7525/issue/view/920
- DOI: https://doi.org/10.31857/S0016-7525647
ARTICLES
Bioavailability and ecotoxicity of metals in aquatic systems: critical levels of pollution
Abstract
The bioavailability and ecotoxicity of metals depending on the geochemical factors of the aquatic environment are considered. For the most metals free ions have the greatest penetration with the exception of some mercury organometallic complexes it has been shown. The models for assessing the danger of pollution of the aquatic environment with metals based on thermodynamic calculations of free ions concentration, the ability of biological receptors to bind them and the toxicological properties of metals, are analyzed. The main mechanisms of penetration and elimination of metals and the cytotoxicity of non-essential elements are considered. A new method for determining critical levels of polymetallic water pollution based on measurements of the complexing ability of waters components and establishing dose-effect relationships between integral indicators of polymetallic water pollution and indicators of ecosystem “health” of ecosystems based on research in the Kola North are presented.
675-688
Effect mass independent isotope fractionation of sulfur (δ33S and δ36S) during photolysis SO2 in experiments with broadband light source
Abstract
This paper presents the results of experimental studies to examine the behavior of mass-independent isotope effects of sulfur Δ33S and Δ36S during photochemical processes initiated by broadband ultraviolet radiation. Experiments were performed in a flow photochemical reactor using a high pressure mercury lamp which is a source of radiation of a wide range with a maximum radiation intensity in the wavelength range 270−330 nm and weaker in the range 190−250 nm. We present measurements of the temperature and SO2 pressure dependence of the sulfur isotope ratios in the elemental sulfur products. Based on a comparative analysis of our isotope data with data from previous experimental studies with xenon and hydrogen lamps, it was shown that the character of the correlation dependences between the values of δ34S, Δ33S and Δ36S in elemental sulfur depends on the relative spectral distribution of the radiation intensity. Based on a comparison of our isotope data with data from previous experimental studies with xenon and hydrogen lamps, it was shown that the character of the correlation dependencies between the values of δ34S, Δ33S and Δ36S in elemental sulfur depends on the relative spectral distribution of the radiation intensity. The results of our experiments allow the possibility that photochemical processes in the range 250−330 nm could play a significant role in the production of an isotope sulfur anomaly in the Archean atmosphere. The conditions in which radiation in the 250−330 nm region prevail over the radiation in the 190−220 nm region are consistent with the assumption that the level of solar radiation reaching the Earth’s surface in Archean was several orders of magnitude larger in the wavelength range 200−300 nm compared with the current level of radiation in this range.
689-699
Physical and chemical conditions of basaltic magmatism of archipelago Franz Josef Land
Abstract
As a result of mineralogical and thermobarogeochemical researches of different-age basaltic complexes of Archipelago Franz Josef Land (FJL) regular changes in time of compositions of plagioclases, clinopyroxenes and melt inclusions are established. Chemical compositions of inclusions directly testify to prevalence in Early Jurassic of plateau basaltic melts similar (according to the content of the basic components, and also trace and rare-earth elements) to typical basalt tholeiitic magma of the Siberian platform. In Early Cretaceous melts already had the enriched subalkaline character. Calculations of conditions of magma generation, spent on the basis of the data on melt inclusions, have shown evolution from Early Jurassic to Early Cretaceous (with allocation of three peaks of magmatic activity: 192.2±2.8, 157.4±3.5 and 131.5±0.8 million years) depths and temperatures (accordingly: 70−110 km and to 120 km, 1430−1580°С; 60−110 km, 1390−1580°С; 50−140 km, 1350−1690°С) of mantle melting with formation of deep sources of the FJL magmas.
700-725
Thermodynamic properties of fluorapophyllite-(k) and hydroxylapophyllite-(k)
Abstract
Thermochemical study of natural minerals of the apophyllite group: fluorapophyllite-(K) KCa4[Si8O20]F . 8H2O (Maharashtra, India) (I) and hydroxylapophyllite-(K) KCa4[Si8O20]OH . 8H2O (Norilsk, Russia) (II) were performed on a high-temperature heat-flux microcalorimeter Tian–Calvet “Setaram” (France) using the melt solution calorimetry method. The first data on the enthalpies of formation from the elements for the minerals studied are obtained: −13 205±13 kJ/mol (I) and −13 054±20 kJ/mol (II). The values of their standard entropies and Gibbs energies of formation are estimated.
726-732
Hydrogeochemistry of urban areas in the Southern Urals
Abstract
On the basis of full-scale studies the features of the formation of the chemical composition of groundwater in urban areas of the Southern Urals have been clarified. Changes in the salt composition of pore solutions of clay rocks and their exchange-adsorption properties, distribution and accumulation of supertoxicants in rocks and water have been established. The influence of changes in the chemical composition of water on hazardous geological processes was evaluated. It was found that the most intense impact of the geological environment is exposed to the surface to a depth of 15−20 m. Dioxins and heavy metals in soils on the territory of industrial enterprises are concentrated in the near-surface zone (up to 5−7 m). In the range of depths from 5−7 m to 20 m their content is significantly reduced. Liquid organic pollutants and water-soluble salts penetrate almost the entire zone of active circulation. The processes of self-purification of aquifers and restoration of natural conditions even after the elimination of the source of pollution continue for tens or even hundreds of years, i.e. exceed the life of one generation.
733-741
Short communications
Genetic linkage of corundum plagioclasites–kyshtymites and miaskites of the Ilmenogorsky–Vishnevogorsky complex, South Urals, Russia: new Rb–Sr and Sm–Nd isotopic, geochemical and mineralogical data
Abstract
New geochemical, mineralogical, and Rb–Sr and Sm–Nd isotopic data have been obtained on corundum plagioclasites–kyshtymites from the 5th Versta deposit (South Urals, Russia). The genetic link of miaskites and kyshtymites is shown. The formation of the kyshtymites is associated with the redistribution and accumulation of aluminum, calcium, HFSE, and LIL-elements at the stage of tectonic-metamorphic deformations of the Ilmenogorsky–Vishnevogorsky alkaline complex.
742-749
High-temperature aquamarine from vugless granite pegmatites of the Suprunovskoye deposit Irkutsk oblast, Russia
Abstract
New data on the chemical composition were obtained for the aquamarine of the Suprunovskoye deposit: SiO2 66.10; Na2O 0.51; Al2O3 17.99; MgO 0.37; K2O 0.03; CaO 0.02; FeO 0.58; BeOcalc. 13.70 (wt%) and fluid and melt inclusions were investigated. Defined that aquamarine was formed in the late stages of granitic magmatism from a specific pegmatite silicate melt or water-silicate liquid enriched with water (>7 wt%), heavy REE (La/Yb = 0.48), lithium, but depleted in fluorine and boron at temperatures of about 700ºС and a pressure of about 6 kbar.
750-756