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020 ▼a 9781085760478
035 ▼a (MiAaPQ)AAI22584903
040 ▼a MiAaPQ ▼c MiAaPQ ▼d 247004
0820 ▼a 574
1001 ▼a Christenson, Elizabeth .
24510 ▼a A Longitudinal, Landscape-Scale Field Study Assessing The Effects of Commercial Hog Operations on Microbial Quality of Surface Waters in North Carolina, Usa.
260 ▼a [S.l.]: ▼b The University of North Carolina at Chapel Hill., ▼c 2019.
260 1 ▼a Ann Arbor: ▼b ProQuest Dissertations & Theses, ▼c 2019.
300 ▼a 218 p.
500 ▼a Source: Dissertations Abstracts International, Volume: 81-03, Section: B.
500 ▼a Advisor: Stewart, Jill .
5021 ▼a Thesis (Ph.D.)--The University of North Carolina at Chapel Hill, 2019.
506 ▼a This item must not be sold to any third party vendors.
520 ▼a North Carolina is one of the leading states in the USA for swine production on commercial hog operations (CHOs). Swine manure from CHOs contains bacteria and antibiotic resistance elements (AREs) and there is concern that CHOs act as sources of fecal bacteria and AREs to surface water through precipitation-driven runoff or leaching. While research has found high concentrations of bacteria and AREs downstream of CHOs, this work did not adequately take into account other fecal sources. Additionally, few studies have appropriately controlled for background levels of resistance so that the effects of CHOs on dissemination of AREs in the environment is difficult to assess.A longitudinal, landscape-scale field study was designed to determine whether there were effects of CHOs on microbial water quality while addressing concerns of bias and confounding between observational groups. This work compared similar, small, agricultural watersheds with (n = 13) and without (n = 9) CHOs over one year and found higher measures of E. coli, swine-associated gene marker, pig-2-bac, and antibiotic resistant E. coli in watersheds with CHOs compared to those without. Resistance to highest priority antibiotics was only observed in sites with CHOs. A multiple linear model was constructed to determine whether higher concentrations of E. coli in sites with CHOs were a result of differences in environmental conditions or exposure to confounding fecal sources. Modeling showed that even when controlling for large effects from precipitation and effects from confounding fecal sources, CHOs contributed E. coli to surface water and had a larger effect compared to human and wildlife sources.Results suggest that microbial water quality is poorer with increasing CHO size and proximity to surface water and that some CHOs may act as sources for human pathogens and AREs in surface water. These results have implications for state and federal policy, suggesting a need to recognize and regulate the discharge from CHOs during dry and wet conditions through discharge permits and/or CHO-specific management plans. Mitigation strategies that should be considered include improvements to CHO manure and land management practices aimed to reduce loading of fecal bacteria to surface water and to limit bacterial transport.
590 ▼a School code: 0153.
650 4 ▼a Microbiology.
650 4 ▼a Public health.
650 4 ▼a Limnology.
690 ▼a 0410
690 ▼a 0573
690 ▼a 0793
71020 ▼a The University of North Carolina at Chapel Hill. ▼b Environmental Sciences and Engineering.
7730 ▼t Dissertations Abstracts International ▼g 81-03B.
773 ▼t Dissertation Abstract International
790 ▼a 0153
791 ▼a Ph.D.
792 ▼a 2019
793 ▼a English
85640 ▼u http://www.riss.kr/pdu/ddodLink.do?id=T15492891 ▼n KERIS ▼z 이 자료의 원문은 한국교육학술정보원에서 제공합니다.
980 ▼a 202002 ▼f 2020
990 ▼a ***1008102
991 ▼a E-BOOK