Importance of hydrogeochemical processes in the coastal wetlands: A case study from Edremit-Dalyan coastal wetland, Balıkesir-Turkey

Investigating the hydrogeochemical properties of wetlands allow us to protect them in a sustainable fashion in global scale. Edremit-Dalyan coastal wetland (EDCW) is located in southern part of Biga Peninsula (Mount Ida) which is the most important eco-tourism center in Turkey. Water sampling was done from the hydrologic basin of coastal wetland that consists of a geothermal site, ore deposits area, treatment facility area and olive tree breeding area. EC values of wetland vary between 440 and 2190 mu S/cm and water type shows a shift from CaHCO3 to NaCISO4. Al, As, Cd, Cu, Fe, Pb and Zn concentrations exceed the tolerance limits in wetland area probably due to ore deposits around the Edremit Plain. Concentrations of As are high in wetland area exceeding both aquatic life and drinking water As standards of 10 mu g/L by as much as 3 times are observed. The dominant As species is As (III). For the living organisms, this situation can be dangerous. Oxygen-18 and deuterium composition of the samples between -7.18 and -6.13 parts per thousand, and between -42.6 and -34.4 parts per thousand respectively in the study area and all the waters are of meteoric origin. Oxygen-18 enrichment can be observed around Derman and coastal zone due to the geothermal activity and evaporation, respectively. (C) 2016 Elsevier Ltd. All rights reserved