The Role of Background Concentrations in the Analysis of the Ecological State of Rivers of the Akhuryan Water Basin Management Area

Abstract The article studies the water quality classes of the Akhuryan, Ashotsk, Karkachun, and Metsamor rivers for 2013-2024 based on the analysis of background concentrations of hydrochemical parameters. The analysis showed that the background concentrations of suspended solids, dissolved oxygen, chemical oxygen demand, biological oxygen demand (5-days), ammonium, nitrite, and phosphate ions, as well as the background concentrations of the following metals: manganese, molybdenum, iron, boron, and arsenic, were exceeded in the waters of the studied river. The analysis of the obtained data can be used for complex management of water resource quality assessment in communities.It was shown that the Water Framework Directive developed by the European Union played an important role in the transition of the river water quality assessment process in Armenia from the assessment of maximum permissible concentrations of hydrochemical parameters to a more comprehensive approach based on natural background concentrations. This amendment, which has been in effect since 2011, emphasizes the importance of ecological integrity and the use of natural river basins for water quality assessment. The RA Government’s Resolution “On Establishing Water Quality Standards for Each River Basin Management Area” distinguishes five separate classes, and the chemical water quality assessment is based on the class with the most unfavorable quality indicator.