Flumethasone

The results of the samples analysed indicated that 23% of the samples tested were positive for the presence of one or more of the selected veterinary drugs, and 43% of them were collected in farming areas. These results could indicate that the presence of the veterinary drugs detected in the water samples collected from rural areas could come from the use of manure contaminated with veterinary drugs (Carballas 1991). Due to the fact that manure samples were not analysed in this study, this affirmation could only be ahypothesis. Eleven drugs were detected in the river samples; trimethoprim, sulfapyridine, sulfaquinoxaline, sulfadiazine, sulfamethoxypyridazine, sulfamethazine, decoquinate, monensin, salinomycin, maduramycin and flumethasone. Among all of the drugs detected in natural water samples, trimethoprim was the most frequently detected in 13 samples which was followed by sulfapyridine in 11 samples. The analytes detected and concentrations are summarized in Table 7.The rest of the pharmaceuticals selected were not detected in any of the river samples; they might be present in the samples but at a concentration below their LOD (Table 4). Figure 2 shows MRM chromatograms of positive samples for decoquinate, flumethasone, sulfadiazine and trimethoprim quantified at 40.0, 85.1, 2978.6 and 126.1 ng L⁻¹ (Table 7), detected in Galician river water samples.