Korean Journal of Soil Science and Fertilizer ISSN:0367-6315(Print) 2288-2162(Online) 한국토양비료학회 학회지

A portion of the veterinary antibiotics administrated to livestock are generally excreted via feces and urine. Tetracyclines and tylosin have a greater priority of environmental risk in Korea based on the consumption and the potential to reach soil and water environment. The antibiotics in animal byproducts need to be reduced or eliminated before they are applied to agricultural lands through composting or other agricultural practices. The objective of the study was to investigate the effect of aeration on degradation of antibiotics during storage of swine slurry. Two antibiotics, tetracycline (TC) and tylosin (TYL), were detected from the swine slurry used in the study. One hour aeration per day for 62 days reduced TC concentration from 199 to 43 ng L^-1 compared with 104 ng L^-1 without aeration. Aeration for three and six hours decreased TC level to 30 and 23 ng L^-1, respectively. The dissipation of TC was fitted with a first-order kinetic model. Aeration for 1, 3, and 6 hours every day increased the first-order rate constant, k, from 0.011day^-1 under anaerobic condition to 0.022, 0.026, and 0.037day^-1, respectively. For TYL, aeration during storage of swine slurry enhanced k from 0.0074 day-1 to 0.014, 0.018, and 0.031day^-1 for 1, 3, and 6 hours per day, respectively. For liquid swine slurry, biotic processes can be more effective for dissipation of antibiotics than abiotic processes because of low organic matter and high water content. These results suggest that aeration can increase the degradation rate of antibiotics during storage of swine slurry.

Measured (symbols) and fitted (lines) concentration of tetracycline (left) and tylosin (right). 0, 1, 3, and 6 denote no aeration, aeration for 1 h, 3 h, and 6 h per day, respectively.