| A significant amount of concern has emerged regarding the presence of antibiotics in the environment and the increase in antibiotic-resistant bacterial infections. This has prompted researchers to study the effects and fate of antibiotics in the environment. Little work has been conducted, however, on the effects and fate of antibiotics in anaerobic lagoons commonly used for waste treatment and storage. This work focused on the inhibition of methanogenesis by antibiotics, sorption of antibiotics to lagoon sediments, and hydrolysis, abiotic and biotic degradation of antibiotics in two central Missouri anaerobic lagoons used at two different confined animal feeding operations (CAFOs) which housed swine. Inhibition studies revealed that antibiotics commonly used in agriculture did partially inhibit methanogenesis in the two anaerobic lagoons studied. Bacitracin A, and three tetracycline, tetracycline, chlortetracycline, and oxytetracycline degraded rapidly in buffered, distilled/deionized water that was maintained at temperatures and pH's commonly encountered in the two study lagoons. However, lincomycin, several studied sulfonamides, and tylosin A were much more recalcitrant. These results do not agree in all cases with results from the abiotic degradation study where autoclaved, lagoon slurry was used. Results from the sorption study of antibiotics to lagoon sediments indicate that the sorption trends varied according to: tetracyclines > tylosin A >> lincomycin > sulfonamides. |
