Phytotoxic effects of irrigation water depending on the presence of organic and inorganic pollutants

Irrigation is one of the most important uses of surface waters in the agricultural region of Vojvodina province (Serbia). The aim of the study was to assess the quality of water from Stara Tisa meander, based on the levels of pollution with metals, volatile compounds (VOC), pharmaceuticals, pesticides, and pathogenic bacteria, on sunflower, cabbage, cucumber, maize, barley, buckwheat, sorghum, radish, beans, and white mustard. Microbiological analysis was carried out using the dilution method and phytotoxicity assay according to ISTA filter paper method (germination energy (GE), germination (G), root and shoot length, fresh and dry weight). The sample was slightly contaminated with domestic, industrial, and agricultural xenobiotics and had low levels of nitrogen substances, metals, and organic micropollutants. Pesticides, metolachlor, tebuconazole, propiconazole, imidacloprid, and thiametoxam were detected at levels exceeding the maximum admissible concentrations (MACs), i.e., the sum value for neonicotinoids. The number of saprophytic (2.27 × 10 6 CFU mL −1 ) and coliform bacteria (5.33 × 10 2 CFU mL −1 ) was very high. The total number of sulphite reducing clostridia (10 cells mL −1 ) and Escherichia coli (5 cells mL −1 ) was very low. The GE and G of all tested plants, except sunflower, were not influenced by the total chemism of water sample. However, it inhibited root lengths of sunflower, cucumber, maize, and barley and stimulated shoot lengths of all species except maize and white mustard. These results indicate that it can be used for irrigation of cabbage and radish from the chemical point of view, but the microbiological traits should be considered prior to consumption since they are consumed raw. The overall results suggest that water from Stara Tisa should be purified before using for agricultural purposes.