|SNOW, DANIEL - University Of Nebraska|
|HENRY, CHRISTOPHER - University Of Arkansas|
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/12/2016
Publication Date: 12/1/2016
Publication URL: http://handle.nal.usda.gov/10113/5695413
Citation: Durso, L.M., Miller, D.N., Snow, D.D., Santin, M., Henry, C.G., Woodbury, B.L. 2016. Evaluation of fecal indicators and pathogens in a beef cattle feedlot vegetative treatment system. Journal of Environmental Quality. 46(1):169-176.
Interpretive Summary: When it rains, feedlot manure gets mixed with the rainwater creating runoff. Feedlot runoff contains microorganisms that are a problem for environmental and human health. So it is important to keep this feedlot runoff water from contaminating surface and ground water sources. One new way of doing this is by creating a Vegetative Treatment System (VTS) that grows perennial grasses using the runoff as irrigation water. We measured how well the VTS removed or eliminated fecal indicator bacteria and pathogens, like E. coli O157:H7 and Salmonella. Over time, both fecal indicator organisms and pathogens are reduced in the soil. For example, Escherichia coli O157:h7 and Salmonella were cultured from 96% and 85% of the runoff samples, respectively, but from less than 1% of the end-of season soil samples. We conclude that the system effectively reduces the concentrations of fecal indicators and pathogens over time. These results indicate that a large-scale, active VTS reduce the potential for environmental or human contamination by manure-associated bacteria.
Technical Abstract: Runoff from open-lot animal feeding areas contains microorganisms that may adversely affect human and animal health if not properly managed. One alternative to full manure containment systems is a vegetative treatment system (VTS) that collects runoff in a sediment basin and then applies it to a perennial vegetation (grass) treatment area that is harvested for hay. Little is known regarding the efficacy of large-scale commercial VTSs for the removal of microbial contaminants. In this study, an active, pump-based VTS designed and built for a 1200-head beef cattle feedlot operation was examined to determine the effects of repeated feedlot runoff application on fecal indicator microorganisms and pathogens over short-term (2 wk) and long-term (3 yr) operations and whether fecal bacteria were infiltrating into deeper soils within the treatment area. In a short-term study, fecal bacteria and pathogen numbers declined over time in soil. Measurements of total coliforms and Enterococcus counts taken on control soils were not effective as fecal indicators. The repeated application of manure-impacted runoff as irrigation water did not enrich the pathogens or fecal indicators in the soil, and no evidence was seen to indicate that pathogens were moving into the deeper soil at this site. These results indicate that large-scale, active VTSs reduce the potential for environmental contamination by manure-associated bacteria. Also, this study has implications to full-containment systems that apply runoff water to land application areas (cropland) and the fate of pathogens in the soils of land application sites.