“Assessment of Spatiotemporal Water Quality Variations, Impact Analysis and Trophic Status of Big Soda Lake Van, Turkey

Abstract

The study was conducted in order to assess the spatiotemporal variations of selected water quality parameters, impact analysis, and trophic status on the Edremit shores of Lake Van. Water samples were collected from 10 representative sampling stations taken from the influent, effluent, and from Lake Van itself in order to analyze the physicochemical parameters in both dry and wet seasons. The trophic status of the lake was determined using Carlson trophic state index. Impact analysis was conducted based on the method most commonly used in management strategies related to surface waters in Turkey. The results of the study show that five factors obtained from principal component indicated that the parameters responsible for water quality changes were mostly related to salts and soda, physicochemical parameters, point and diffuse pollutions discharge, and other organic pollutants. In the impact analysis pH, COD (chemical oxygen demand), BOD (biological oxygen demand), and TP (total phosphorus) (except for EC (electrical conductivity)) parameters were found to have medium impact, while DO (dissolved oxygen) and TN (total nitrogen) parameters had no impact. The pH, EC, SO4−2, Cl−, TP, COD, and BOD values measured at 10 sampling stations were considered to be Class IV according to national regulations. The final trophic status of lake, according to the Carlson trophic index, was assessed to be eutrophic. Understanding this variation is important so as to develop new ways to resolve issues of sustainable water management. In addition, it is considered essential to prepare guidelines for the trophic status of Lake Van.