Assessment of water pollution in a waste storage drainage area (a case study in Eskişehir, Türkiye)

Before 2016, the Eskişehir city landfill was an irregular landfill. Since then, it has been transformed into a regulated landfill. This study aimed to investigate the presence of pollution in the landfill drainage area. For this purpose, water samples were collected from the landfill drainage area and the Kadirbey Farm Spring, upstream of the landfill area, during the rainy and dry seasons of 2021. Analyses of the heavy metal content, total dissolved soil (TDS), chemical oxygen demand, biochemical oxygen demand, pH, phenol material content, ammonia nitrogen content, and conductivity were conducted on the samples. Electrical resistivity tomography (ERT) measurements were also performed along the stream bed. According to Turkish Soil Water Quality regulations, the TDS concentrations of all the samples, except one, were lower than the limits for class 3 water quality. The conductivity limits were within the acceptable range for class 3 water quality. The pH of the water samples was alkaline. The calculated leachate pollution index values indicated a pollution risk. The heavy metal pollution index values for the water samples were under 100. Additionally, 75% of the samples were in the very pure category according to the heavy metal evaluation index, with the remaining samples classified as slightly affected. According to the ERT measurements, soils with low resistivity near the landfill were notably laterally wider. The conductivity decreased with the increasing distance from the landfill site. Low resistivity zones, such as plumes, were disconnected from each other. The shape and volume of highly contaminated plumes decreased toward BH1. Based on the study outcomes, it is recommended to measure the water pollution parameters at periodic intervals within the landfill drainage area.