Occurrence of ß-lactam and polyether ionophore antibiotics in lagoon water and animal manure

The occurrence of micropollutants in agricultural wastes is an emerging area of interest due to the potential impact of these compounds on the environment. A sensitive and reliable analytical method using liquid chromatography-electrospray tandem mass spectrometry has been developed and validated for the determination of three ss-lactam and three polyether ionophore antibiotics in lagoon water and animal manure matrices. The method was applied to evaluate the occurrence of these compounds from participating farms in northern Colorado. Seven of the 19 lagoon water samples and two of the six animal manures showed detectable. The three targeted ss-lactams (cephapirin, penicillin G, cloxacillin) were found at 0.97-43.31 mu g/L in the lagoon water samples. Of the three targeted polyether ionophores, only monensin (94 to 1077 mu g/L) was detected in the beef runoff pond water samples. Only cloxacillin was measured in the dairy animal manure samples at levels from 8.09 to 45.20 mu g/kg. No cephapirin, penicillin G, cloxacillin, salinomycin, or narasin A were detected in any solid animal manure sample. These results indicate that elevated concentrations of ss-lactamand ionophore compounds might be found in lagoon or runoff pond waters and solid animal manures compared to surface waters, which these compounds are used in veterinary applications. (c) 2018 Elsevier B.V. All rights reserved.