Chromatographic analysis of chemical pollutants in river ecosystems in the northwest of Türkiye

The Meric-Ergene Basin is situated in the Thrace region of northwestern Türkiye, representing a significant hydrological subunit within the country’s transboundary water systems. In addition to intensive agricultural practices within the basin, water pollution originating from both industrial and urban sources constitutes one of the major environmental challenges in the region. In this study, water samples were taken from localities with different sources of pollution in the Meric, Ergene and Tunca River, which are important surface sources of the Meric-Ergene Basin, at seasonal intervals for a year. pH and electrical conductivity were measured using EPA standard methods, while suspended particulate matter was determined with GF/F glass microfiber filters. Heavy metals and other elements were analyzed directly by ICP-MS; anions were analyzed by IC; pesticides, phthalate esters, and bisphenol-A analyses were performed by LC-MS/MS. The analyses employed chromatographic techniques due to their high sensitivity, repeatability, and dependability. As a result, even trace amounts of contaminants could be found. All experimentally obtained data were evaluated in accordance with the criteria set forth in the Water Pollution Control Regulation of Türkiye. Average metal concentrations in the Ergene River, notably those of Co, Cr, Cu, and Fe, were found to surpass regulatory thresholds. Furthermore, Carbendazim, Thiamethoxam, Acetamiprid, Metalaxyl, and Azoxystrobin emerged as the most commonly applied pesticide compounds within the Meric-Ergene River Basin. Bis(2-ethylhexyl) phthalate values were found to be above limits. Bisphenol-A was only found at some stations in the summer. The results of this research provide data to improve water protection and human health monitoring in the Meric-Ergene River Basin.