Investigation some physico-chemical properties of the freshwater sources feeding the bay of Gökova in Turkey by geographic information systems

Abstract

Gökova Bay in Turkey has been under the threat of pollution particularly in summer months because of high tourism activities and visitors numbers. In this study, the water quality of freshwater sources (Kadın Creek, Akcapınar Creek and Çamlı Stream) that feed to Gökova Bay were investigated by using Geographic Information Systems (GIS) between November 2014 and October 2015. Water samples were taken from 13 geo-referenced strategic points (stations) and their physico-chemical parameters were analyzed. Investigated water variables were temperature (oC), pH, ,electrical conductivity EC (µScm-1), salinity (‰), solid suspended matter (mgL-1), ortho phosphate (mgL-1), total phosphorus (mgL-1), nitrite nitrogen NO2-N (mgL-1), nitrate nitrogen NO3-N (mgL-1), ammonium Nitrogen NH4-N (mgL-1), saturated oxygen (%), dissolved oxygen (mgL-1) and biological oxygen demand BOD (mgL-1). The spatial analysis of the collected data was conducted in GIS, and a thematic map of each water variable was developed by using the nearest neighborhood interpolation technique. Differences between sampling stations and the differences between sampling periods were investigated by ANOVA, and both differences were found statistically important. The relationships among the water variables were researched by correlation (Pearson) analysis. The relationship between EC (µScm-1) and salinity (‰) and the relationship between biological oxygen demand BOD (mgL-1) and dissolved oxygen (mgL-1) were found statistically important, and these two relationships were modelled by using the best fit regression method. Results of the water analyses were evaluated and interpreted according to Water Pollution and Control Regulations of the Ministry of Environment and Urbanization.