377 Bulletin UASMV serie Agriculture 70(2)/2013, 377-382 Print ISSN 1843-5246; Electronic ISSN 1843-5386 The Salty Lakes of Ocna Sibiului. Past. Present. Future Tania MIHAIESCU* 1) , Manuela CUC 1) , Mihnea Andrei MIHAIESCU 2) 1) Faculty of Agriculture, Department of Environment and Plant Protection, University of Agricultural Sciences and Veterinary Medicine, 3-5 Manastur St., RO-400372 Cluj-Napoca, Romania; tania.mihaiescu@usamvcluj.ro 2) Faculty of Geography, Babes-Bolyai University, 1 Mihail Kogalniceanu St., RO-400084, Cluj- Napoca, Romania Abstract. At the center of the Transyvanian Plateau lies Ocna Sibiului, with its salt deposits which, in places, run up to one thousand meters below the surface. The presence of these deposits has been favored, due the extraction of salt throughout the years causing the formation of the now famous salt lakes. Due to different environmental conditions, lacustrine cuvettes and water quality differ from one lake to another. The studied lakes are considered to be in conection with the salt deposits exposed through minig activities carried on in different time periods. Other lakes in the area already are isolated from salt deposits due to natural sedimentation proceses. The study adresses the lakes which still present a high degree of salinity and are used for balnear purposes, and present, due to various factors, variation of physical-chemical composition throughout the year. Water samples were collected from the main six lakes in Ocna Sibiului (Ocniţa – Avram Iancu; Rândunica; Negru; Fără Fund; Brâncoveanu and Gura Minei). Surveys were carried out in four periods (March-November) during 2012.Water temperature, electrical conductivity (at 25ｰC) and pH were measured in-situ. The water pH changed from a lake to another. Generally it is within the range of 6.78 to 8.8 highlighting the neutral to slightly alkaline lake water. Salt lake water conductivity values, in the upper layers vary within a wide range, from more than 200 mS cm -1 to 45.7 mS cm -1 , with different values from the different lacustrine units. The salt water lakes are characterized by high content of sodium and chlorine ions. The other major ions are present in a small amount. This paper aims to compare the past and present evolution, characteristics and environment of these lakes, , and, based on this and current research, to project a vision of their future and how it will affect the lives of future generations living besides them. Keywords: Ocna Sibiului, salty lake, Transylvania, physico-chemical characteristics INTRODUCTION Throughout the Transylvanian Plateau numerous artificial salt lakes formed in derelict salt mines are widely distributed (Alexe, 2010). At the center of the Transyvanian Plateau lie the salt deposits of Ocna Sibiului which, in places, run up to one thousand meters below the surface. The presence of these deposits favored the formation of the now famous salt lakes, formed due the extraction of salt throughout the centuries. These anthropic, or more specifically, anthropic-salted lakes, have a small surface area of a few thousand square meters, yet feature great depths and contribute to a specific landscape, representing the main source of income for the local economy. Ocna Sibiului is a tourist resort located in Sibiu County. In the southern hills of the Transylvanian Plateau (north-west of Sibiu Depression) 15 km north of Sibiu, in the Visa valley, a region surrounded by cenntenial oak forests and rich in salt deposits. The presence of these deposits favoured the formation of the now famous salt lakes. The first spa was established in 1845 and since then, Ocna Sibiu has attracted a reputation for heliothermic treaments.