Determination of heavy metal pollution in Meric-Ergene river basin sediments

In the study, it was aimed to determine heavy metal accumulation in sediment samples in Meriç-Ergene Basin. For this purpose, 3 semi-metal, 11 metal and TOC concentrations were determined in 82 sediment samples collected at 41 sampling points selected by considering the pollutant source relationship and upstream-downstream relationship in 2 different periods, July 2020 and December 2020 in Meriç-Ergene River Basin. The results obtained were evaluated in terms of pollution factor values, their relationships with each other and source distributions with various statistical evaluations. When the results obtained are evaluated in general, TOC and heavy metal values measured in the industrial area in the basin and samples for the 2nd period (December 2020) for all sampling points were determined at high levels. Average values of TOC measurements vary between 0.7-8.6% for all stations. Heavy metal cocentrations were found at high levels when compared to literature values. The correlation between TOC values and heavy metal species, which are known to be caused by industrial and domestic discharge, have been found to be high for many metals for a confidence interval of 0.01. In the study, cluster analysis was performed on the basis of heavy metal and sampling points. It has been determined that heavy metal groups are divided into 2 groups indicating industrial and agriculture + domestic pollution. In the cluster analysis of the sampling points, three distinct clusters were analyzed and it was determined that the HCA results clearly express the pollutant source group distributions of the sampling points and the heavy metal concentration distributions especially in the agricultural and industrial regions. In the study, the size of heavy metal pollution in sediments was determined for each sampling point by various indices such as enrichment factor (EF), pollution factor (CF), pollution load index (PLI), geoaccumulation factor (Igeo) and potential ecological risk index (PERI). In the results of the study, all the indices calculated for sampling points in sediments especially in industry-intensive regions point to heavy pollution. Moderate and / or severe pollution was observed in reference areas in terms of Cd, in agriculture-intensive areas and industrial-intensive areas in the region. The values of Cd, Cr, Cu, Pb and Zn in industry intensive areas pointed to medium and / or heavy contamination in all indices. Low, medium or heavy contamination in terms of Cd, Cu and Pb was observed in all indices at some points in the agriculture-intensive regions. This situation was thought to be caused by heavy metals in the fertilizers and pesticides used.