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Pathogenic E. Coli and Enterococci in Streambed Sediments after Land Application of Swine Lagoon Effluent
Waste discharges from agricultural operations, particularly spreading animal manure on cropland, may be a source of pathogenic microorganisms in impaired waters. Pathogens may enter waterways from croplands by direct runoff and/or by tile drainage. Once in surface waters, pathogens may be transported downstream or settle into streambed sediments, to later be released during periods of increased stream flow. Through exposure in recreational waters and contaminated drinking water resources, pathogens of fecal origin pose significant risk to human health and welfare.
Understanding pathogen transport is imperative to establishing sound manure management practices that will lead to improved water quality in agricultural areas. This study aims to better understand the impact of applying swine wastewater lagoon effluent to croplands on the bacteriological quality of nearby receiving waters. Fecal bacteria, including E. coli, enterococci, and fecal Bacteroidetes, will be monitored. To determine delivery ratios of applied swine wastes, monitoring will occur upstream from, downstream of, and alongside the application area, as well as in tile drainage lines. E. coli and enterococci harboring genetic virulence traits and/or exhibiting resistance to clinically relevant antimicrobials will be used as markers for bacterial pathogenicity. Sampling over the schedule of the hydrograph during rainfall events will aid in identifying potential changes in pathogen loads to downstream waters due to increased runoff, tile drainage, and resuspension of fecal bacteria from streambed sediments. The results will be compiled into a conceptual model of how pathogens may be transported from cropland that was treated with animal waste lagoon effluents to receiving waters through runoff, storage, and drain tile discharge. The results of this study are expected to complement ongoing research concerning the reduction of environmental risk from synthetic and natural hormones, pharmaceuticals, and nutrients originating from concentrated animal feeding operations.
Contact: Shane Rogers (EIMS#131317)