Chemistry for Sustainable Development 15 (2007) 329-342 Processes of Chemical Weathering of Minerals in Sulphide-Containing Tailing Dumps: Modeling of the Composition of Vadose Water and Secondary Phases

Abstract Thermodynamic model of the oxidative leaching of sulphide-rich tailings from dressing of gold-containing ores (Berikul settlement, West Siberia) is investigated. When calculating the water-rock interactions, we applied some special approaches allowing one to determine the effect of the degree of reaction progress and change of the parameters of the medium (E h , pH) on the composition of the formed secondary minerals that restrain the development of acid drainage at the objects of this kind. Substantiation of several stages of the formation of a technogenic system in time and space is presented, depicting the approach of the system to equilibrium with the environment. The distinguished stages correspond to the zoning of mineral associations described at the object. These associations were formed during 50 years of storing the tailing mounds from the lowest weakly oxidized sulphide parageneses with gypsum and covellite to the capping jarosite-quartz-gypsum zones. The results of modelling provide evidence that an increase in rock affection by atmospheric water brings about the conditions favourable for the formation of the "final" association (goethite and quartz); however, this association is not stable even on the surface of the Berikul tailing dump. It is concluded on the basis of preliminary evaluation that hypergenesis processes in the objects of this kind may proceed hundreds of years till complete depletion of the acid-producing and toxic potential of industry-related wastes

REE, Uranium (U) and Thorium (Th) contents in Betula pendula leaf growing around Komsomolsk gold concentration plant tailing (Kemerovo region, Western Siberia, Russia)

The article deals with the research findings of peculiarities of REE, Uranium and Thorium distribution in the territory surrounding the tailing of former Komsomolsk gold concentration plant according to the data from Betula pendula leaf testing. In the leaf element composition the slight deficiency of MREE and substantial excess of HREE are presented. In the nearest impacted area around the tailing, La, Yb, U and Th content, and Th/U ratio are lower than in the distant buffer area. It is shown, that value of Th/U ratio and REE can be an indicator for geochemical transformations of technogenic landscapes in mining districts. The results of the research can be used for biomonitoring of the territory around the tailing

РАСПРОСТРАНЕННОСТЬ КАРДИАЛЬНЫХ ФАКТОРОВ РИСКА У ПАЦИЕНТОВ С АНЕВРИЗМОЙ БРЮШНОЙ АОРТЫ

Introduction. According to the literature, 27 to 65 % of patients with abdominal aortic aneurysm also suffer from coronary heart disease. Mortality from coronary heart disease after surgical treatment for abdominal aortic aneurysm according to some data exceeds 20 %.Objective: improvement of results of treatment of patients with combined lesions of coronary arteries and aneurysm of the abdominal aortaSubjects and method. A retrospective analysis of case histories of 100 patients hospitalized in our clinic diagnosed with «abdominal aortic aneurysm» for examination. Of all patients, 37 % were diagnosed with significant coronary artery lesions. The average ejection fraction was 58.2 ± 5.4 %, 13 % of the study diagnosed significant violations of local myocardial contractility. 16 % of patients had previous myocardial infarction, 7 % – a permanent form of atrial fibrillation. 4 % of patients complained of chest pain during exercise. Hypertension was present in 100 % of patients, the average maximum systolic blood pressure was 176 ± 24.5 mmHg.Results. Hospital mortality was 2 % (all patients were non-operated on coronary arteries and had no significant coronary pathology). There were no significant complications (cardiac, neurological, respiratory) in the early postoperative period. The average length of hospital stay was 9.8 ± 1.99 bed days.Conclusions. Determination of cardiac status before surgery for abdominal aortic aneurysm is the most important moment of stratification of the risk of perioperative complications. Coronary angiography in patients with abdominal aortic aneurysm is a mandatory point of diagnosis, allowing to identify cardiac risk factors.Введение. Согласно данным литературы, от 27 до 65 % пациентов с аневризмой брюшной аорты также страдают ишемической болезнью сердца (ИБС). Смертность от ИБС после оперативного лечения по поводу аневризмы брюшной аорты, по некоторым данным, превышает 20 %.Цель: улучшение результатов лечения пациентов с сочетанным поражением коронарных артерий и аневризмой брюшной аорты.Материал и методы. Проведен ретроспективный анализ историй болезни 100 пациентов, госпитализированных в ОАП НМИЦССХ им. А. Н. Бакулева с диагнозом «аневризма брюшной аорты» для обследования. Из всех пациентов у 37 % диагностированы значимые поражения коронарных артерий. Средний показатель фракции выброса составил 58,2 ± 5,4 %, у 13 % по данным исследования диагностированы значимые нарушения локальной сократимости миокарда. 16 % пациентов ранее перенесли инфаркт миокарда, у 7 % отмечена постоянная форма фибрилляции предсердий. 4 % пациентов предъявляли жалобы на загрудинные боли при физической нагрузке. Артериальная гипертензия присутствовала у 100 % пациентов, средний показатель максимального систолического артериального давления составил 176 ± 24,5 мм рт. ст.Результаты. Госпитальная летальность составила 2 % (все пациенты, не имеющие значимой коронарной патологии, ранее не оперированы на коронарных артериях). Значимых осложнений (кардиальных, неврологических, респираторных) в раннем послеоперационном периоде не отмечалось. Средняя длительность пребывания в стационаре составила 9,8 ± 1,99 койко-дня.Выводы. Определение кардиального статуса перед оперативным вмешательством по поводу аневризмы брюшной аорты – важнейший момент стратификации риска развития периоперационных осложнений. Выполнение коронарографии у пациентов с аневризмой брюшного отдела аорты является обязательным пунктом диагностики, позволяющим выявить кардиальные факторы риска

Chemistry for Sustainable Development 20 (2012) 375384 Features of Soil Pollution in the Region of Storage of the Wastes from Pyrometallurgical Zinc Extraction at the Belovo Zinc Plant

Abstract Total heavy metal content in the soil in the region of the storage of wastes from pyrometallurgical works (Belovo Zinc Plant) was investigated. It was established that the high level of zinc and copper pollution is conserved also after the plant stops its operation. The maximal pollution was detected in the direct vicinity of clinker mound; it exceeds the background values for zinc by a factor of 60. At a distance of 300 m pollution decreases (17-fold excess over the background value) but it can be followed even at a distance of 5 km from the Belovo Zinc Plant (5-fold level). The fraction of mobile forms of a number of elements extracted through stepwise leaching was determined. For the soil with the heaviest pollution (ðÍ of water extract 5.58), the fraction of mobile zinc forms exceeds the MPC by a factor of 66, copper by a factor of 2, manganese is below the normal value, mobile forms of nickel were not detected. Thus obtained row depicts the geoecological condition of soil in the region of waste storage of the Belovo Zinc Plant

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