ANALYSIS OF THE ECOLOGICAL STATE OF RIVERS OF THE ARARAT WATER BASIN MANAGEMENT AREA USING BACKGROUND CONCENTRATIONS

Abstract

The article argues that an inherent limitation of maximum permissible concentrations is their inability consider the specificities of the geographical areas. In this regard, the Water Framework Directive developed by the European Union has played an important role in shifting river water quality assessment in Armenia from assessing maximum permissible concentrations of hydrochemical parameters to a more comprehensive approach which based on  natural background concentrations. This shift, in force since 2011, emphasizes the importance of ecological integrity and  use of natural reference points at the rivers for water quality assessment. The Decree of the Government of the Republic of Armenia “On Establishing Water Quality Standards for Each Basin Authority” distinguishes five separate classes and the assessment of chemical water quality is based on the class with the least favourable quality indicator. Water quality classes of the Vedi, Arpa and Yeghegis rivers for the period 2013–2024 were studied based on the analysis of background concentrations. The analysis showed that in a river  waters  under study the background concentrations of suspended solids, chemical oxygen demand, ammonium, nitrite and phosphate ions, as well as the following metals: manganese, molybdenum, aluminum, iron, barium and tin are exceeded.