DOCSLIB.ORG

The Impact of Climate Changes on the Aquatic System Chemistry in the Kyiv Reservoir and the Desna River (Ukraine)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Impact of Climate Changes on the Aquatic System Chemistry in the Kyiv Reservoir and the Desna River (Ukraine) EGU2020-9677 https://doi.org/10.5194/egusphere-egu2020-9677 EGU General Assembly 2020 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. The impact of climate changes on the aquatic system chemistry in the Kyiv Reservoir and the Desna river (Ukraine) Valeriy Osypov, Volodymyr Osadchyi, Natalia Osadcha, Olha Ukhan, and Nina Mostova Ukrainian Hydrometeorological Institute, Hydrochemistry, Kyiv, Ukraine ([email protected]) The Kyiv Reservoir and the Desna river are the main sources of drinking water supply for Kyiv, the capital of Ukraine. The impact of surface air temperature on the change of the aquatic system chemistry mentioned above water objects was studied based on long-term regular observations (1995–2018). The findings are based on the analysis of daily air and water temperature, water pH, oxygen and carbon dioxide concentrations, water color index, dissolved organic substances (CODMn), Fe, Mn, and phytoplankton abundance (without identifying their species composition). The winter period. Despite different hydraulic conditions in the Kyiv Reservoir and in the Desna river, the lack of ice cover due to an increase in winter air temperatures (December-February) led to significant improvement of the water oxygen regime in recent years. This fact, as well as the subsequent chain of changes in the water chemistry, contributed to the cheaper drinking water supply. The ratio of the oxygen content change to the duration of the ice cover, determined by air temperature, was obtained. This allowed us to reconstruct years with observed hypoxia phenomena since 1850. Changes in the water chemistry, triggered by oxygen deficit, were described. The summer period. The increase in summer air temperature led to a decrease in oxygen + concentrations. It had the effect of slowing down the process of N-NH4 nitrification. Because of the high content of natural organic matters in these water bodies, dangerous hypoxia phenomena were reported in summertime. Such conditions contributed to the restoration of manganese to a mobile Mn2+. All these features created additional difficulties at water treatment plants for supplying drinking water to residents of Kyiv. In shallow waters, occupying almost half of the Kyiv Reservoir, an increase in water temperature during the summer period led to the intensification of the hydrobiological processes and “water blooming.” This is compounded by the high income of nitrogen and phosphorus from the point and diffuse sources. The observed decrease in the Dnieper water flow does not allow the active use of releases from the Kyiv Reservoir. The only way to minimize negative consequences in the future is to prevent pollution and eliminate shallow water zones. This is complicated by the fact that a significant amount of nitrogen compounds enters the Kyiv Reservoir with the water of its main tributary, Pripyat, which basin is highly marshy. Dredging in the shallow areas will require further research because of the bedding of radionuclides of Chernobyl in the bottom sediments. Powered by TCPDF (www.tcpdf.org).
Load more

Recommended publications
  • Anthropogenic Transformation of Hydrological Regime of the Dnieper River
    Manuscript Number: 2701 Indian Journal of Ecology (2018) 45(3): 445-453 NAAS Rating: 4.96 Anthropogenic Transformation of Hydrological Regime of The Dnieper River Vitalii Ivanovich Pichura, Daria Sergeevna Malchykova1, Pavel Aleksandrovich Ukrainskij2, Iryna Aleksandrovna Shakhman and Anastasiia Nikolaevna Bystriantseva1 Kherson State Agricultural University, Ukraine, 73006, Kherson, Stritens'ka str. 23, 1Kherson State University, Ukraine, 7300 0, Kherson, Universitets'ka str. 27, 2Belgorod State National Research University, Russian Federation, 308015, Belgorod, 85 Pobedy Str. E-mail: [email protected] Abstract. Problems of rational water use and water quality assessment are the priorities of many states, especially in the basins of transboundary rivers. Creation and functioning of the cascade of Dnieper reservoirs led to a radical transformation of the hydrological regime of the Dnieper River. As a result, there occurred a significant deterioration of the physical, chemical and biological characteristics of surface water quality, increase of its trophic state, reduction of the efficiency and stability of the aquatic ecosystem of the Dnieper basin, which is largely determined by anthropogenic factors. As a result of interpretation the series of space images (August, 1986-2016) of the satellites Landsat- 5, Landsat- 7 and Landsat-8 with a spatial resolution of 30 meters, the spatio-temporal trend of changes in physical (water transparency), hydrochemical (general phosphorus concentration in water), biological (chlorophyll-a) properties of water areas of reservoirs was determined. In studies trophic state index developed by the Florida Department of Environmental Protection was used to classify all types of water surface, including rivers. It is established that the value of trophic state index in reservoirs is distributed unevenly from 26.5 to 56.5.
    [Show full text]
  • PRESERVING the DNIPRO RIVER Harmony, History and Rehabilitation PRESERVING the DNIPRO RIVER
    PRESERVING THE DNIPRO RIVER harmony, history and rehabilitation PRESERVING THE DNIPRO RIVER harmony, history and rehabilitation International Dnipro Fund, Kiev, Ukraine, National Academy of Sciences of Ukraine, International Development Research Centre, Ottawa, Canada, National Research Institute of Environment and Resources of Ukraine PRESERVING THE DNIPRO RIVER harmony, history and rehabilitation Vasyl Yakovych Shevchuk Georgiy Oleksiyovich Bilyavsky Vasyl M ykolayovych Navrotsky Oleksandr Oleksandrovych Mazurkevich Library and Archives Canada Cataloguing in Publication Preserving the Dnipro River / V.Y. Schevchuk ... [et al.]. Includes bibliographical references and index. ISBN 0-88962-827-0 1. Water quality management--Dnieper River. 2. Dnieper River--Environmental conditions. I. Schevchuk, V. Y. QH77.U38P73 2004 333.91'62153'09477 C2004-906230-1 No part of this book may be reproduced or transmitted in any form, by any means, electronic or mechanical, including photocopying and recording, information storage and retrieval systems, without permission in writing from the publisher, except by a reviewer who may quote brief passages in a review. Publishing by Mosaic Press, offices and warehouse at 1252 Speers Rd., units 1 & 2, Oakville, On L6L 5N9, Canada and Mosaic Press, PMB 145, 4500 Witmer Industrial Estates, Niagara Falls, NY, 14305-1386, U.S.A. and International Development Research Centre PO Box 8500 Ottawa, ON K1G 3H9/Centre de recherches pour le développement international BP 8500 Ottawa, ON K1G 3H9 (pub@ idrc.ca / www.idrc.ca)
    [Show full text]
  • Chernobyl Heritage and the E40 Trans-Europe Waterway
    2020 Chernobyl heritage and the E40 trans-Europe waterway Study commissioned by the Frankfurt Zoological Society January 2020 ACRO | 138 rue de l’Eglise – 14200 Hérouville St Clair – France | (+33) 2 31 94 35 34 | acro.eu.org | [email protected] ACRO – Chernobyl heritage and the E40 trans-Europe waterway TERMS OF REFERENCE Objectives Radioactive contamination analysis Organisation Frankfurt Zoological Society Offer PR190521(01)-SZF-v1 ANALYSIS Association pour le Contrôle de la Radioactivité dans l’Ouest 138, rue de l’Eglise 14200 Hérouville Saint-Clair France www.acro.eu.org phone: +33 (0) 2.31.94.35.34 / email: [email protected] SIRET 950 369 868 00027 | APE 7120 B Authors David Boilley, Ala Pigrée, and Pierre Barbey Cover picture Pripyat river © Olga Kaskevich DOCUMENT Publication date January 2020 Identification RAP_E40_en Version 01 Pages 46 pages Title Chernobyl heritage and the E40 trans-Europe waterway CONDITIONS From ACRO: Reproduction of the document is authorized only in the form of a complete facsimile. 2 ACRO – Chernobyl heritage and the E40 trans-Europe waterway Summary The E40 waterway aims to connect the Black Sea to the Baltic Sea, via the Dniepr and Prypiat rivers. But, the whole Dnieper watershed is contaminated by 1986 Chernobyl accident. Furthermore, the Prypiat crosses the Chernobyl Exclusion Zone and passes immediately next to the Chernobyl nuclear power plant. The present study aims to give a first evaluation of the radiologic impact of the construction and maintenance of the E40. The two important radioelements from a public health perspective are cesium-137 and strontium-90.
    [Show full text]
  • Environmental Performance Reviews Ukraine
    ECONOMIC COMMISSION FOR EUROPE Committee on Environmental Policy ENVIRONMENTAL PERFORMANCE REVIEWS UKRAINE UNITED NATIONS New York and Geneva, 1999 Environmental Performance Reviews Series No. 6 NOTE Symbols of United Nations documents are composed of capital letters combined with figures. Mention of such a symbol indicates a reference to a United Nations document. The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city of area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. UNITED NATIONS PUBLICATION Sales No. E.00.II-E.1 ISBN 92-1-116743-4 ISSN 1020-4563 iii Preface The Environmental Performance Review of Ukraine started with its preparatory mission in November 1997. This mission resulted in the agreed structure of the review. The team carrying out the review consisted of national and international experts. The national team members were made available by Bulgaria, Finland, France, Germany, Italy, Lithuania, Netherlands and Switzerland. Technical advisers from Germany (on water protection technology) and Italy (on air pollution abatement, waste treatment and measurement technologies) assisted the team in their areas of competence. The Rome Division of the WHO European Centre for Environment and Health, UNEP and the ECE secretariat provided the international experts. The costs of participation of experts from countries in transition, as well as the travel expenses of the ECE secretariat, were covered from extrabudgetary funds provided by France, Germany, Italy and the Netherlands.
    [Show full text]
  • 10. the BASE CASE ALTERNATIVE As Noted in Section 1, EBRD
    Tacis Nuclear Safety Environmental Impact Assessment for Khmelnitsky 2 NPP 10. THE BASE CASE ALTERNATIVE As noted in Section 1, EBRD environmental procedures require a comparison of impacts from the proposed project, i.e. completion and upgrading of R4/K2 and closure of the Chornobyl NPP, with the base case, i.e. the current situation with Chornobyl Unit 3 in operation and the possibility of both Units 2 and 3 operating. This Section provides a brief introduction to the state of the power industry in Ukraine in the last few years (Section 10.1) as a prelude to a discussion of such a comparison (Section 10.2). 10.1 Power generation and the nuclear contribution 1991-1995 Ukraine became independent in 1991 and immediately experienced a severe recession. Gross domestic product (GDP) fell from the equivalent of US$ 155.6 billion in 1990 to US$ 68.8 billion in 1995 (both at 1990 prices), a large balance of payments deficit developed (US$ 1.2 billion in 1995) and inflation became rampant [10.1]. Primary energy consumption mirrored the slump in the economy by dropping rapidly from 1991 to 1995 (Table 10.1). Ukraine has a once-large but declining coal industry. In addition to the decline in production (from 131 Mt in 1991 to 66 Mt in 1995) the quality of the coal being mined also declined. The country became a net importer of coal in 1992 and relies heavily on imported oil and gas from Russia (e.g. 66 billion m3 of gas and 13 Mt of oil from Russia and Turkmenistan in 1995).
    [Show full text]
  • Development of Draft River Basin Management Plan for Dnipro River Basin in Ukraine: Phase 1, Step 1 – Description of the Characteristics of the River Basin
    European Union Water Initiative Plus for Eastern Partnership Countries (EUWI+): Results 2 and 3 ENI/2016/372-403 DEVELOPMENT OF DRAFT RIVER BASIN MANAGEMENT PLAN FOR DNIPRO RIVER BASIN IN UKRAINE: PHASE 1, STEP 1 – DESCRIPTION OF THE CHARACTERISTICS OF THE RIVER BASIN Report February 2019 Responsible EU member state consortium project leader Ms Josiane Mongellaz, Office International de l’Eau/International Office for Water (FR) EUWI+ country representative in Ukraine Ms Oksana Konovalenko Responsible international thematic lead expert Mr Philippe Seguin, Office International de l’Eau/International Office for Water (FR) Authors Ukrainian Hydrometeorological Institute of the State Emergency Service of Ukraine and National Academy of Sciences of Ukraine Mr Yurii Nabyvanets Ms Nataliia Osadcha Mr Vasyl Hrebin Ms Yevheniia Vasylenko Ms Olha Koshkina Disclaimer: The EU-funded program European Union Water Initiative Plus for Eastern Partnership Countries (EUWI+ 4 EaP) is implemented by the UNECE, OECD, responsible for the implementation of Result 1 and an EU member state consortium of Austria, managed by the lead coordinator Umweltbundesamt, and of France, managed by the International Office for Water, responsible for the implementation of Result 2 and 3. This document “Assessment of the needs and identification of priorities in implementation of the River Basin Management Plans in Ukraine”, was produced by the EU member state consortium with the financial assistance of the European Union. The views expressed herein can in no way be taken to reflect the official opinion of the European Union or the Governments of the Eastern Partnership Countries. This document and any map included herein are without prejudice to the status of, or sovereignty over, any territory, to the delimitation of international frontiers and boundaries, and to the name of any territory, city or area.
    [Show full text]
  • Useful-2-1-2018-0003-Vasilenko
    Volume 2, Issue 1, 2018 https://useful.academy ISSN 2574-4461 (online) Publisher: SVP4U-KYIV-1-FUND LLC DOI: https://doi.org/10.32557/useful Qualitative analysis of water supply of the city of Kyiv Lesya Vasilenko Ph.D. a, Olena Zhukova Ph.D. b, Julia Bereznitska Ph.D. c a Kyiv National University of Construction and Architecture, Address: 03037, Povitroflotsky Avenue, 31, Kyiv, Ukraine P: +38 (093) 543-2684, E: [email protected] b Kyiv National University of Construction and Architecture, Address: 03037, Povitroflotsky Avenue, 31, Kyiv, Ukraine P: +38 (096) 875-2104, E: [email protected] с Kyiv National University of Construction and Architecture, Address: 03037, Povitroflotsky Avenue, 31, Kyiv, Ukraine P: +38 (044) 241-54-91, E: [email protected] ORCID iDs a https://orcid.org/0000-0003-4201-5481 b https://orcid.org/0000-0003-0662-9996 c https://orcid.org/0000-0001-7953-3974 ARTICLE INFO Article history: Received March 10, 2018; Accepted March 18, 2018 Available online March 20, 2018 DOI: https://doi.org/10.32557/useful-2-1-2018-0003 License: Under a creative commons license CC BY-NC-ND 4.0 https://creativecommons.org/licenses/by-nc-nd/4.0/ Original language: Ukrainian Keywords: qualitative depletion, quantitative depletion, environment, nature management, water pollution index, ecological index. Please cite as: Lesya Vasilenko Ph.D, Olena Zhukova Ph.D, Julia Bereznitska Ph.D. Qualitative analysis of water supply of the city of Kyiv USEFUL online journal 2018; 2(1) URL: https://useful.academy/ ISSN 2574-4461 (online) DOI: https://doi.org/10.32557/useful-2-1-2018-0003 Lesya Vasilenko Ph.D, Olena Zhukova Ph.D, Julia Bereznitska Ph.D.
    [Show full text]
  • Peculiarities of Zooplankton Cenosis
    Ukrainian Journal of Ecology Ukrainian Journal of Ecology, 2021, 11(6), 63-68, doi: 10.15421/2021_224 ORIGINAL ARTICLE Peculiarities of zooplankton cenosis structure and Ukrainian Journal of Ecology,2021, 11(4),,doi: 10.15421/2021_ development in the middle water area of Kremenchuk Reservoir, Dnieper River (Ukraine), in conditions of elevated temperatures N.Ya. Rudyk-Leuska1*, M.I. Khyzhniak1, M.V. Leuskyi1, N.Yu. Yevtushenko1, V.M. Kondratіuk1, R.V. Kononenko1, N.I. Tson1 1National University of Life and Environmental Sciences of Ukraine, Heroiv Oborony Str., 15, Kyiv, 03041 Ukraine *Corresponding author E-mail: [email protected] Received: 20.07.2021. Accepted: 31.07.2021. An analysis of the research results on the quantitative and qualitative composition of zooplankton in the middle part of the Kremenchuk reservoir in the water area near Chervona Sloboda, Lesky, and Khudyaki in August 2016 is presented аt elevated temperatures. Of particular note is the first decade of the month, when there was a shift in maximum temperature to +25.42 ± 0.15°C (Cv=1.86%). In general, the water temperature was unstable; its maximum values were a stress factor for plankton invertebrates of the reservoir. It is established that for each section of the water area, certain specific Rotifera species are characteristic of zooplankton: Hexarthra mira (Hudson, 1871)–at station 1; Lepadella patella (O.F. Muller, 1786), Mytilina mucronata (Müller, 1773), Brachionus forficula Wierzejski, 1891, Br. budapestinensis (Daday, 1885)–at station 2; Polyarthra euryptera (Carlin 1943; Bartos 1950; Nipkow 1952; Sudzuki 1964), Lecane luna (Müller, 1776), Synchaeta monopus (Plate, 1889), Asplanchna priodonta var.
    [Show full text]
  • Technical Report: Description of the Characteristics of Dnipro River Basin
    European Union Water Initiative Plus for Eastern Partnership Countries (EUWI+): Results 2 and 3 ENI/2016/372-403 TECHNICAL REPORT: DESCRIPTION OF THE CHARACTERISTICS OF DNIPRO RIVER BASIN. SUMMARY Version 2.0 - January 2020 Responsible EU member state consortium project leader Ms Josiane Mongellaz, Office International de l’Eau/International Office for Water (FR) EUWI+ country representative in Ukraine Ms Oksana Konovalenko Responsible international thematic lead expert Mr Philippe Seguin, Office International de l’Eau/International Office for Water (FR) Responsible Ukrainian thematic lead experts Mr Oleksandr Bon, Ministry of Ecology and Natural Resourcesof Ukraine Mr Mykhailo Khoriev, State Agency of Water Resources Mr Valerii Babchuk, State Agency of Water Resources Authors Ms Yevheniia Vasylenko (Ukrainian Hydrometeorological Institute of the State Emergency Service of Ukraine and National Academy of Sciences of Ukraine) Ms Olha Koshkina (Ukrainian Hydrometeorological Institute of the State Emergency Service of Ukraine and National Academy of Sciences of Ukraine) Disclaimer: The EU-funded program European Union Water Initiative Plus for Eastern Partnership Countries (EUWI+ 4 EaP) is implemented by the UNECE, OECD, responsible for the implementation of Result 1 and an EU member state consortium of Austria, managed by the lead coordinator Umweltbundesamt, and of France, managed by the International Office for Water, responsible for the implementation of Result 2 and 3. This document, the “TECHNICAL REPORT: DESCRIPTION OF THE CHARACTERISTICS OF DNIPRO RIVER BASIN. EXECUTIVE SUMMARY”, was produced by the EU member state consortium with the finan- cial assistance of the European Union. The views expressed herein can in no way be taken to reflect the offi- cial opinion of the European Union or the Governments of the Eastern Partnership Countries.
    [Show full text]
  • Multi-Side Approach to the Realities of the Chernobyl NPP Accident - Summing-Up of the Consequences of the Accident Twenty Years After (II)
    Multi-side Approach to the Realities of the Chernobyl NPP Accident - Summing-up of the Consequences of the Accident Twenty Years After (II) - Report of a research grant from the Toyota Foundation (November 2004 – October 2006) Project leader Imanaka T. May 2008 チェルノブイリ原発事故の実相解明への多角的アプローチ － 20 年を機会とする事故被害のまとめ(II) － トヨタ財団助成研究 （2004 年 11 月～2006 年 10 月） 研究報告書（英語版） 研究代表者 今中哲二 200８年５月 Preface This is the English version report of the international collaboration study, “Multi-side Approach to the Realities of the Chernobyl NPP Accident: Summing-up of the Consequences of the Accident Twenty Years” which was carried out in November 2004 – October 2006 supported by a research grant from the Toyota Foundation. Twenty three articles by authors of various professions are included about Chernobyl. The Japanese version was already published in August 2007, which contains 24 articles. (http://www.rri.kyoto-u.ac.jp/NSRG/tyt2004/CherTYT2004.htm) Out of them, 12 articles are included in both versions. As a specialist of nuclear engineering, I have been investigating the Chernobyl accident since its beginning. Before the 20th anniversary of Chernobyl, I hoped to start a new project to try to make an overview of “Chernobyl disaster” by collecting various viewpoints of persons who have been involved in Chernobyl in their own ways: scientists, journalists, NGO activists, sufferers etc. I thought that a new image of Chernobyl could be constructed through learning different viewpoints. Fortunately the Toyota Foundation supported my proposal. I think we could make a unique report about Chernobyl. In addition to this report, the following two reports were already published through the previous collaborations: ¾ Research Activities about the Radiological Consequences of the Chernobyl NPS Accident and Social Activities to Assist the Sufferers by the Accident.
    [Show full text]
  • Nuclear and Radiation Safety in Ukraine Annual Report 2002
    STATE NUCLEAR REGULATORY COMMITTEE OF UKRAINE Nuclear and Radiation Safety in Ukraine Annual Report 2002 KYIV – 2003 LIST OF ABBREVIATIONS ABDBA - Analysis of Beyond Design Basis Accidents ADBA - Analysis of Design Basis Accidents AWT - Active Water Treatment CF - Capacity Factor ChNPP - Chornobyl NPP CMU - Cabinet of Ministers of Ukraine CPS - Control and Protection System CR - Control Rods DE - Deep Evaporator ECCS - Emergency Core Cooling System ER - Exposure Rate FCM - Fuel Containing Materials FE - Fuel Element FS - Feasibility Study GICS - Group and Individual Control System IAEA - International Atomic Energy Agency IACS - Integrated Automated Control System IMS - In-core Monitoring System RF - Reference Specimen IRC - Ionising Radiation Source KhNPP - Khmelnitsky NPP Liquid Radwaste - Liquid Radioactive Waste LRSF - Liquid Radwaste Storage Facility MFE - Ministry of Fuel and Energy of Ukraine MSB - Multi-Place Sealed Basket MSI - Main State Inspectorate for Nuclear and Radiation Safety NF - Nuclear Facility NNEGC - National Nuclear Energy Generating Company ”Energoatom” Energoatom NPP - Nuclear Power Plant INR - Scientific Centre “Institute for Nuclear Research” PPM - Planned Preventive Maintenance PSA - Probabilistic Safety Analysis Radwaste - Radioactive Waste RC - Refuelling Container RCP - Reactor Coolant Pump RF - Reactor Facility RICP - Radioactive Waste Interim Confinement Point RM - Radiation Monitoring RNPP - Rivne NPP RV - Reactor Vessel RWDP - Radioactive Waste Disposal Point SAR - Safety Analysis Report SCFR - Self-Sustained
    [Show full text]
  • Twenty-Five Years After Chornobyl Accident: Safety for the Future»
    Ministry of Ukraine of Emergencies All-Ukrainian Scientific Research Institute for Civil Defense of population and territories from technogenic and natural emergences. «Twenty-five Years after Chornobyl Accident: Safety for the Future» National Report of Ukraine Кyiv 2011 УДК 621.311.25:621.039.586](477.41-21) ББК 31.47(4Укр-4Киї)-08 Д22 To compile the National Report materials of the following organizations were used: Ministry of Ukraine of Emergencies, Ministry of Energy and coal-mining industry of Ukraine, Ministry of Public health of Ukraine, State Nuclear regulatory inspection of Ukraine, Committee on Environmental Policy, Use of Natural Resources and Elimination of Consequences of Chornobyl Disaster at Verkhovna Rada of Ukraine, National Academy of Sciences of Ukraine, National Academy of medical sciences of Ukraine, National Academy of Agrarian Sciences of Ukraine, National Commission on Radiological Protection of Ukraine. The materials included in the report were compiled by: Abramenko I.V. (3.3.3); Bazyka D.A. (3.3; 7.5.1); Baklan V.A. (8.2); Balashov L.S. (2.1.3); Bakhanova Ye.V. (3.1.1); Bebeshko V.G. (3); Belousova L.P. (7.3.2); Bilyj Д.O. (3.3.1); Bogdanova T.I. (3.2.4); Bondarenko G.M. (2.1.3); Borysyuk M.M. (7; 8); Boyuk L.T. (7.2.4); Buzunov V.O. (3.2); Vasylenko V.V. (3.1.3); Vdovenko V.Yu. (3.2.3); Vynograds’ka V.D. (2.2.3); Voznyuk V.M. (7.2.1.); Voytsekhovytch О.V. (2.1.1; 2.2.2); Voytchulene Yu.S.
    [Show full text]