Optimization of the Sample Preparation Procedure and Determination of the Content of REE and Ge in Low Carbonized Rocks by the ISP-MS Method Using a Triple Quadrupole

В работе представлены результаты исследований химического состава образцов лигнита Касского месторождения методом масс-спектрометрии с индуктивно связанной плазмой (ИСП-МС) с акцентом на определение редкоземельных элементов и германия. С учетом данных термогравиметрического анализа (ТГА) оптимизированы условия пробоподготовки образца с применением микроволнового разложения и механохимической активации, обеспечивающих практически полную минерализацию проб. Разработана методика ИСП-МС‑определения германия и РЗЭ в лигните на приборе “Agillent 8800” с тройным квадруполем и оценены ее метрологические характеристики. Показано, что лигниты Касского месторождения характеризуются содержанием германия и РЗЭ в количествах, перспективных для промышленного извлеченияThe paper presents the results of investigations of the chemical composition of lignite samples from the Kasskoye deposit by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) with an emphasis on the determination of rare earth elements (REE) and germanium. Taking into account the data of thermogravimetric analysis (TGA), the conditions for sample preparation were optimized using microwave decomposition and mechanochemical activation, which ensure almost complete mineralization of the samples. An ICP-MS method was developed for the determination of germanium and REE in lignite on an Agillent 8800 device with a triple quadrupole, and its metrological characteristics were evaluated. It is shown that the lignites of the Kass deposit are characterized by the content of germanium and REE in quantities that are promising for industrial extractio

THE STUDY OF CADMIUM UPTAKE BY WATER HYACINTH (EICHHORNIA CRASSIPES) USING A NATURAL MODELLING APPROACH

The results of the investigation on the accumulation of cadmium by water hyacinth, depending on the conditions of pollutant exposure and the presence of various additives are discussed. The main specialty of this study is that all the experiments were carried out in natural conditions using the approach based on the application of the capacities called minicosms. It allowed estimating hit consequences of pollutant on ecosystem most really having made experiment in the conditions as much as possible close to the natural. In this article a very important problem of an accuracy and reliability of the results of trace elements determination in plants is also debated. As a result of carried investigations it was shown that the degree of cadmium extraction by hyacinth from contaminated natural water while maintaining the viability of the plants depends on the way of pollutant introducing into the reservoir and the maximum (about 79%) value is observed in the case of it’s gradual entry

Study of the Effect of Squalene Epoxidase Activity on Squalene Biosynthesis by Yeast Saccharomyces Cerevisiae VGSh-2

The researchers of this study investigated the biosynthesis of squalene by the yeast S. cerevisiae VGSH-2 through the activity of squalene epoxidase, which is a key enzyme in the conversion of squalene to ergosterol. It has been established that under aerobic conditions the antimycotic drug terbinafine promotes the switching of ergosterol formation to squalene synthesis. This switch occurs through specific inhibition of the squalene epoxidase of the yeast S. cerevisiae VGSH-2, thus increasing the biosynthetic ability of the yeast towards squalene. According to the results of this study, the optimal concentration of terbinofine in the nutrient medium was 0.3 μmol / cm3 . This concentration led to a 5-fold decrease in squalene epoxidase activity and a 7-8 times increase in squalene synthesis. The results obtained can be used to develop a competitive technology for the industrial production of squalene by microbial synthesis. Keywords: squalene, yeast, biosynthesis, inhibition of activity, terbinafine, squalene epoxidase, Saccharomices cerevisiae VGSH-

Determination of Arsenic Species Distribution in Arsenide Tailings and Leakage Using Geochemical and Geophysical Methods

This study describes the distribution of arsenic mobile species in the tailings of Cu–Co–Ni–arsenide using the sequential extraction and determining the contents of arsenate (AsV) and arsenite (AsIII). The object of this study is the tailings ponds of the Tuvakobalt plant, which contains waste from the hydrometallurgical arsenide ore processing of the Khovu-Aksy deposit (Republic of Tuva, Russia). A procedure of sequential extraction for arsenic was applied, and it includes the extraction of the following forms: water-soluble, potentially water-soluble and exchangeable, easily sorbed on the surface of carbonates, associated with Fe/Mn oxides/hydroxides, associated with easily oxidized minerals, and accounted for by non-oxidized arsenic minerals. This procedure, which takes into account the peculiarities of the physical and chemical composition of the waste, was supplemented by the analytical determination of the arsenite and arsenate content by using the methods of inductively coupled plasma atomic emission spectrometry (ICP-AES) combined with the hydride generation technique (HG-ICP-AES). The content of the most mobile forms of arsenic, which are water-soluble, potentially water-soluble, and exchangeable species, is equal to 56% of the total arsenic content, 23% and 33% of which are arsenite and arsenate, respectively. Unlike arsenic, the mobile forms of metals have been determined in small quantities. The largest proportion of water-soluble and exchangeable forms is formed by Mg, Ca, and Sr at 11, 9.4, and 20%, respectively (residual and redeposited carbonates). The proportion of water-soluble forms of other metals (Cu, Zn, Co, and Ni) is < 1% or 0. The main part of the metals is adsorbed on the surface of Fe and Mn hydroxides, enclosed in easily and hardly oxidized minerals. In addition to geochemical studies, the presence of leaks from the tailing ponds into ground waters was determined by using electrical resistivity tomography. The data obtained indicate a high environmental hazard of tailings and the possibility of water-soluble and highly toxic arsenic compounds entering ground waters and aquifers

Изучение состава минералов Hg в природно-техногенных системах

Mercury speciation and the composition of mercury phases in natural and mining-related environments is studied by the thermal release analysis combined with electrothermal atomic absorption spectroscopy (TA-ET-AAS), as well as scanning electron microscopy with energy-dispersive X-ray microanalysis (SEM-EDS). The analyses are applied to laboratory-made samples bearing mercury selenide and to field samples from sites known for relatively high natural or industrially induced Hg background. They are, namely, material from the dispersion train of the Ursk sulfide tailings (Ursk Village, Kemerovo region) and debris precipitated from snow sampled in the Kurai mercury zone (Aktash Village, Gorny Altai). The TA-ET-AAS method works well in discrimination and identification of Hg sulfide and Hg selenide provided that the samples contain sufficient amounts of both compounds, but the sum HgS + HgSe can be determined at any contents of the two compounds. The presence of both mercury sulfide and mercury selenide in the samples has been confirmed by SEM-EDS microanalysis. The temperature ranges for the mercury species (Hg2+; HgS+HgSe mixture; mercury bound with organic matter (Hg-OM), including CH3Hg+) are identical in the laboratory and field samples. Therefore, the suggested approach can ensure fast and reliable detection of Hg phases in rocks exposed to supergene alterationДля изучения состава минералов ртути в природных и техногенных объектах предложен подход, сочетающий метод термического анализа с электротермическим атомно-абсорбционным детектированием (ТА-ЭТА-ААС) и сканирующую электронную микроскопию (СЭМ ЭДС). Исследования проводили с использованием модельного образца, содержащего селенид ртути, а также образцов, отобранных на объектах, характеризующихся повышенным природным и техногенным геохимическим фоном ртути, а именно: вещества потока рассеяния хвостохранилища Ново-Урского месторождения (п. Урск, Кемеровская область) и твердого осадка снега Курайской ртутной зоны (п. Акташ, Горный Алтай). Показано, что применение метода ТА-ЭТА-ААС для разделения и идентификации сульфида и селенида ртути возможно при значительных содержаниях обоих соединений в исследуемых образцах, т. е. при сравнительно небольших разбавлениях, однако при этом определение суммы HgS и HgSe возможно при любых содержаниях данных форм. Присутствие обеих форм подтверждается данными СЭМ ЭДС. Показано, что интервалы температурных выходов изучаемых форм ртути (Hg2+; смесь HgS/HgSe; Hg-OM (форма, связанная с органическим веществом, в том числе CH3Hg+)) в модельных и реальных образцах совпадают. На основании чего можно полагать, что предложенный подход может быть с успехом применен для быстрой и надежной идентификации минералов ртути в гипергенных условия