Date of this Version
Joy, Stacey R. FATE AND TRANSPORT OF ANTIMICROBIAL AND ANTIMICROBIAL RESISTANCE GENES IN SOIL AND RUNOFF AFTER LAND APPLICATION OF SWINE MANURE. 2013, University of Nebraska, Lincoln, Nebraska, Master of Science
Antimicrobial resistance is considered one of the world’s most pressing public health issues. One source of antimicrobials in the environment is animal agriculture. Antimicrobials are used for growth promotion, prophylaxis, and for disease treatment within concentrated animal feed operations (CAFOs). Antimicrobials may allow resistant bacteria to proliferate in manure applied as fertilizer, and therefore antimicrobials and antimicrobial resistant genes (ARGs) may contaminate surface and ground water. The fate and transport of antimicrobials, ARGs in soil and surface runoff is quantified in this study after land applications of surface applied and injected swine manure. Rainfall simulations were conducted after manure containing chlortetracycline, bacitracin, or tylosin was applied by broadcast, incorporation, or injection methods. Soil and runoff samples were collected and analyzed for antimicrobials in the liquid phase through high pressure liquid chromatograph or liquid chromatography tandem mass spectrometry, respectively. Published qPCR protocols were followed to determine the concentration of ARGs in manure, soil, and runoff for tetQ, tetX, ermB, and ermF. Significant vertical transport of ARGs was not detected in the soil samples. Antimicrobials and ARGs decreased in runoff throughout the three day experiment. The transport of antimicrobials is affected by manure application methods, and the timing of rainfall, as lower antimicrobial concentrations were observed in runoff after the third runoff event. The aqueous transport of antimicrobials is modeled through the SWAT pesticide sub-routine.
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