Integrated Environmental Quality Assessment of Kizilirmak River and its Coastal Environment

Abstract

Kizilirmak River receives substantial loads of nutrients, trace metals and other compounds, resulting from anthropogenic activities within its catchment. The main aims of this research were to evaluate spatial and seasonal trends in water discharge, nutrients and trace metals and also to compare data with water and sediment quality criteria and with certain quality indices such as water quality index (WQI), sediment quality index (SQI) and trophic state index (TSI), identifying the environmental pressures and assessing the impact of the loads to the coastal environment. Nine stations were sampled within the main stream of Kizilinnak River near to the Black Sea. Field measurements and routine laboratory water analysis were carried on the eight sampling stations seasonally. Wet sediment sample analyses were also performed for EC, pH, organic matter and moisture content within the range of 1.13-1.76 mS; 7.52-8.80; 1.41-4.60%; 18.92-33.65%, respectively. However, trace metal analyses including Cd, Ni and Pb were done by Atomic Absorption Spectroscopy (AAS) both on water and sediment samples with the total digestion methods. Since the analytical cost involved could be a limiting factor for river quality assessments in developing countries, certain quality indices were used in this study. For each type of indices calculations, different approaches from the literature were selected and compared. Calculated NSFWQI, WQI(new), and WQI(min.) values are in good agreement and the water quality of the river is considered at medium level. For the Derbent Dam of Kizilirmak River, two different trophic level index calculations have also the same results indicating eutrophic conditions where algal growth and blooms can occur. However, certain metal quality indices both for water and sediment measurements indicate that the river has medium quality of lead pollution which may be caused by automobile exhausts and urban storm run-off.