Global production and need for food supply are dramatically increasing around the world with increase in population. In order to grow more resistant and high quality crops as food supply for increasing population, agricultural crops are protected by using different types of agricultural chemicals. However, high consumption of these chemicals is ultimately harmful for the environment and  living organisms due to their toxic, persistent and bioaccumulative properties. Even though there are regulations set for the limitations of  pesticide usage, pesticide levels present in different environmental compartments (ground water, river, sediment) are substantially high regarding to the residue limits. Especially when freshwater sources are considered, pesticides pose great threat both for human health and ecological life due to their bioaccumulative and toxic characteristics. Reduction of contamination originated from these pesticides in freshwater systems is quite difficult to apply without detection of major contamination sources. Therefore, sources of these dangerous micropollutants should be determined and their fate in the environment should be understood in detail by considering the impact of environmental conditions and chemical characteristics of pesticides on concentration trend of them within the freshwater environment. Through this study, it is aimed to determine agricultural sources of pesticide pollution in Yeşilırmak River Basin and to analyze their concentration trend throughout time and location by incorporating impact of pesticide chemical properties (half-life, solubility and adsorption capacity on soil (Koc), etc.) on pesticide pollution level within the river basin. Besides, the effects of seasonal changes on pesticide concentration variation within the river basin will be taken into account with pesticide usage periods for planted crops. In the light of this study, agricultural practices can be applied to the problematic fields and misuse or overuse of pesticides can be prevented by developing new farming strategies in order to control pesticide usage and reduce high pollution levels within the Yeşilırmak River Basin.  

By: Büşra Selin Yanar

Advisor: Prof. Dr. Ülkü Yetiş

Date: 20.03.2019