Determination of pesticide residues in Ergene river

This study investigates pesticide residues in the Ergene River where runoff pesticides from surrounding agricultural areas and discharges of industrial wastewater into the river basin. Water samples were collected from the selected 13 sampling locations based on types of the crop and industry among the Ergene River basin in July and August of 2020. LC-MSMS was used to measure the pesticides having high solubility in water samples after filtering with a 0,22 µm pore size of syringe filters. The rest of the pesticides in the water samples were measured by GC-MS/MS right after liquid-liquid extraction, sample cleaning, and solvent exchange processes. To validate the EPA, ISO, and ASTM methods, UPLC-Xevo TQ-XS MS/MS (Zspray ESI+ Source) device for water-soluble pesticides and 7890B APGC-Xevo TQ-XS MS/MS/MS for solvent-soluble pesticides were used in our analytical instruments. Pesticides were identified by using Waters MassLynx V4.2 software, improving data acquisition and processing features for mass spectrometry with MS (APGC+ Source) device. The detection limit (LOD), the limit of quantification (LOQ) were calculated from the signal to noise ratios for pesticides. Recovery for the samples ranged from 80 % to 120%. Total 435 pesticides were scanned in the water samples. A 25 of them identified which are 2-Phenylphenol, 3,4-Dichloroaniline, Acetamiprid, Alachlor, Biphenyl, Bispyribac, Carbendazim, Chloroneb, Chlorotoluron, Chlorsulfuron, Clomazone, Cypermethrin Beta, Diazinon, Diphenylamine, Fenpropathrin, Fipronil, Imidacloprid, Metalaxyl, Metribuzin, Oxadiazon, Phenthoate, Piperonyl butoxide, Pretilachlor, Pyrimethanil ve Thiamethoxam. The highest concentrations of 2-Phenylphenol Metribuzin were 0,14 mg/L and 2,08 mg/L, respectively. A-8 out of 25 identified pesticides were banned in Turkey and concentrations ranged from 4,14 ng/L to 439,35 ng/L. The residual pesticides detected in the Ergene River are closely related to the agricultural activities around the river basin. Further investigation needs to be done on the sources of pesticides.