Gradual Changes in Water Quality Parameters in Razim-Sinoe Aquatic Complex in the Period 1991-2017

Abstract

This paper discusses the evolution in time of water quality parameters in Razim-Sinoe aquatic complex, the largest surface water in the natural system in Romania, situated in the southern part of the Danube Delta Biosphere Reserve. For this purpose, data regarding mean values of nutrients concentrations (nitrogen from ammonium, nitrogen from nitrite, nitrogen from nitrate, phosphorus from orthophosphates) and salinity (chloride, sulphates, calcium, magnesium and sodium) were collected between 1991 and 2017 from Razim and Golovita lakes. Our results revealed a gradual increase in nutrients concentrations by the year 2010, followed by a significant decreasing trend after this year. In the same time, a decreasing tendency in salts content was remarked throughout the study period. Still, over the monitored period 1991-2017, exceeding were reported of the reference value for good ecological status (second quality class) for chlorides, sulphates, calcium, magnesium and sodium, in accordance with Water Framework Directive (2000/60/EC), transposed into Romanian legislation through the Order 161/2006 for the approval of the Normative concerning the classification of surface water quality in order to establish the ecological status of water bodies.

Keywords

• nutrients
• salinity
• Razim-Sinoe