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Devane M, Dupont PY, Robson B, Lin S, Scholes P, Wood D, Weaver L, Webster-Brown J, Gilpin B. Mobilization of Escherichia coli and fecal source markers from decomposing cowpats. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 853:158509. [PMID: 36063947 DOI: 10.1016/j.scitotenv.2022.158509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/28/2022] [Accepted: 08/30/2022] [Indexed: 06/15/2023]
Abstract
In rural environments, the sources of fecal contamination in freshwater environments are often diffuse and a mix of fresh and aged fecal sources. It is important for water monitoring purposes, therefore, to understand the impacts of weathering on detection of the fecal source markers available for mobilization from livestock sources. This study targets the impacts of rainfall events on the mobilization of fecal source tracking (FST) markers from simulated cowpats decomposing in situ for five-and-a-half-months. The FST markers analysed were Escherichia coli, microbial source tracking (MST) markers, fecal steroids and a fecal ageing ratio based on the ratio between counts of river microflora and total coliforms. There was a substantial concentration of E. coli (104/100 mL) released from the ageing cowpats suggesting a long-term reservoir of E. coli in the cowpat. Mobilization of fecal markers from rainfall-impacted cowpats, however, was markedly reduced compared with fecal markers in the cowpat. Overall, the Bacteroidales bovine-associated MST markers were less persistent than E. coli in the cowpat and rainfall runoff. The ten fecal steroids, including the major herbivore steroid, 24-ethylcoprostanol, are shown to be stable markers of bovine pollution due to statistically similar degradation rates among all steroids. The mobilizable fraction for each FST marker in the rainfall runoff allowed generation of mobilization decline curves and the derived decline rate constants can be incorporated into source attribution models for agricultural contaminants. Findings from this study of aged bovine pollution sources will enable water managers to improve attribution of elevated E. coli to the appropriate fecal source in rural environments.
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Affiliation(s)
- Megan Devane
- Institute of Environmental Science and Research Ltd., (ESR) 27 Creyke Rd, Ilam, Christchurch, New Zealand.
| | - Pierre-Yves Dupont
- Institute of Environmental Science and Research Ltd., (ESR) 27 Creyke Rd, Ilam, Christchurch, New Zealand
| | - Beth Robson
- Institute of Environmental Science and Research Ltd., (ESR) 27 Creyke Rd, Ilam, Christchurch, New Zealand
| | - Susan Lin
- Institute of Environmental Science and Research Ltd., (ESR) 27 Creyke Rd, Ilam, Christchurch, New Zealand
| | - Paula Scholes
- Institute of Environmental Science and Research Ltd., (ESR) 27 Creyke Rd, Ilam, Christchurch, New Zealand
| | - David Wood
- Institute of Environmental Science and Research Ltd., (ESR) 27 Creyke Rd, Ilam, Christchurch, New Zealand
| | - Louise Weaver
- Institute of Environmental Science and Research Ltd., (ESR) 27 Creyke Rd, Ilam, Christchurch, New Zealand
| | - Jenny Webster-Brown
- Waterways Centre for Freshwater Management, University of Canterbury, Christchurch, New Zealand
| | - Brent Gilpin
- Institute of Environmental Science and Research Ltd., (ESR) 27 Creyke Rd, Ilam, Christchurch, New Zealand
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Wiesner-Friedman C, Beattie RE, Stewart JR, Hristova KR, Serre ML. Characterizing Differences in Sources of and Contributions to Fecal Contamination of Sediment and Surface Water with the Microbial FIT Framework. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:4231-4240. [PMID: 35298143 DOI: 10.1021/acs.est.2c00224] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Surface water monitoring and microbial source tracking (MST) are used to identify host sources of fecal pollution and protect public health. However, knowledge of the locations of spatial sources and their relative impacts on the environment is needed to effectively mitigate health risks. Additionally, sediment samples may offer time-integrated information compared to transient surface water. Thus, we implemented the newly developed microbial find, inform, and test framework to identify spatial sources and their impacts on human (HuBac) and bovine (BoBac) MST markers, quantified from both riverbed sediment and surface water in a bovine-dense region. Dairy feeding operations and low-intensity developed land-cover were associated with 99% (p-value < 0.05) and 108% (p-value < 0.05) increases, respectively, in the relative abundance of BoBac in sediment, and with 79% (p-value < 0.05) and 39% increases in surface water. Septic systems were associated with a 48% increase in the relative abundance of HuBac in sediment and a 56% increase in surface water. Stronger source signals were observed for sediment responses compared to water. By defining source locations, predicting river impacts, and estimating source influence ranges in a Great Lakes region, this work informs pollution mitigation strategies of local and global significance.
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Affiliation(s)
- Corinne Wiesner-Friedman
- Gillings School of Global Public Health, Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7400, United States
| | - Rachelle E Beattie
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin 53233, United States
| | - Jill R Stewart
- Gillings School of Global Public Health, Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7400, United States
| | - Krassimira R Hristova
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin 53233, United States
| | - Marc L Serre
- Gillings School of Global Public Health, Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7400, United States
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