Location: Agroecosystem Management ResearchTitle: Fate and transport of antimicrobials and antimicrobial resistance genes in soil and runoff following land application of swine slurry Author
Submitted to: Journal of Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/17/2013
Publication Date: 9/17/2013
Publication URL: http://handle.nal.usda.gov/10113/59349
Citation: Joy, S.R., Bartelt-Hunt, S.L., Snow, D.D., Gilley, J.E., Woodbury, B.L., Parker, D.B., Marx, D.B., Li, X. 2013. Fate and transport of antimicrobials and antimicrobial resistance genes in soil and runoff following land application of swine slurry. Journal of Environmental Science and Technology. 47:12081-12088. DOI: ORG/10.1021/ES4026358. Interpretive Summary: Animal production is an important source of antimicrobials and antimicrobial resistant bacteria to the environment. Antimicrobials may allow resistant bacteria to proliferate in animal manure and, therefore, antimicrobials and antimicrobial resistance genes may be transported to surface and ground water after manure is land applied as fertilizer. The objective of this study was to investigate the fate and transport of antimicrobials and antimicrobial resistance genes in soil and surface runoff following land application of swine slurry. Rainfall simulation tests were conducted after swine slurry containing three selected antimicrobials was applied via broadcast (surface application), incorporation, or injection methods. Both antimicrobials and antimicrobial resistance genes were detected in runoff after swine slurry application, indicating the potential for transport of these constituents to surface waters. Antimicrobial and antimicrobial resistance genes concentrations in runoff decreased over the three-day experiment. No significant vertical transport of antimicrobial resistance genes was detected in the soil. 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.
Technical Abstract: Due to the use of antimicrobials in livestock production, residual antimicrobials and antimicrobial resistance genes (ARGs) could enter the environment following the land application of animal wastes and could further contaminate surface and groundwater. The objective of this study was to determine the effect of various manure land application methods on the fate and transport of antimicrobials and ARGs in soil and runoff following land application of swine manure slurry. Swine manure slurries were obtained from facilities housing pigs that were fed chlortetracyline, tylosin or bacitracin and were land applied via broadcast, incorporation, and injection methods. Three rainfall simulation tests were then performed on amended and control plots. Results show that land application methods had no statistically significant effect on the aqueous concentrations of antimicrobials in runoff. However, among the three application methods tested broadcast resulted in the highest total mass loading of antimicrobials in runoff from the three rainfall simulation tests. The aqueous concentrations of chlortetracyline and tylosin in runoff decreased in consecutive rainfall events, although the trend was only statistically significant for tylosin. For ARGs, broadcast resulted in significantly higher erm genes in runoff than did incorporation and injection methods. In soil, the effects of land application methods on the fate of antimicrobials in top soil were compound specific. No clear trend was observed in the ARG levels in soil, likely because different host cells may respond differently to the soil environments created by various land application methods.