1
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Hachad M, Burnet JB, Sylvestre É, Duy SV, Villemur R, Sauvé S, Prévost M, Qiu JY, Pang X, Dorner S. β-D-glucuronidase activity triggered monitoring of fecal contamination using microbial and chemical source tracking markers at drinking water intakes. WATER RESEARCH 2024; 254:121374. [PMID: 38422696 DOI: 10.1016/j.watres.2024.121374] [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: 10/23/2023] [Revised: 02/22/2024] [Accepted: 02/23/2024] [Indexed: 03/02/2024]
Abstract
Intense rainfall and snowmelt events may affect the safety of drinking water, as large quantities of fecal material can be discharged from storm or sewage overflows or washed from the catchment into drinking water sources. This study used β-d-glucuronidase activity (GLUC) with microbial source tracking (MST) markers: human, bovine, porcine mitochondrial DNA markers (mtDNA) and human-associated Bacteroidales HF183 and chemical source tracking (CST) markers including caffeine, carbamazepine, theophylline and acetaminophen, pathogens (Giardia, Cryptosporidium, adenovirus, rotavirus and enterovirus), water quality indicators (Escherichia coli, turbidity) and hydrometeorological data (flowrate, precipitation) to assess the vulnerability of 3 drinking water intakes (DWIs) and identify sources of fecal contamination. Water samples were collected under baseline, snow and rain events conditions in urban and agricultural catchments (Québec, Canada). Dynamics of E. coli, HF183 and WWMPs were similar during contamination events, and concentrations generally varied over 1 order of magnitude during each event. Elevated human-associated marker levels during events demonstrated that urban DWIs were impacted by recent contamination from an upstream municipal water resource recovery facility (WRRF). In the agricultural catchment, mixed fecal pollution was observed with the occurrences and increases of enteric viruses, human bovine and porcine mtDNA during peak contaminating events. Bovine mtDNA qPCR concentrations were indicative of runoff of cattle-derived fecal pollutants to the DWI from diffuse sources following rain events. This study demonstrated that the suitability of a given MST or CST indicator depend on river and catchment characteristics. The sampling strategy using continuous online GLUC activity coupled with MST and CST markers analysis was a more reliable source indicator than turbidity to identify peak events at drinking water intakes.
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Affiliation(s)
- Mounia Hachad
- NSERC Industrial Chair on Drinking Water, Department of Civil, Geological, and Mining Engineering, Polytechnique Montréal, QC, H3C 3A7, Canada; Canada Research Chair in Source Water Protection, Department of Civil, Geological, and Mining Engineering, Polytechnique Montréal, QC, H3C 3A7, Canada.
| | - Jean-Baptiste Burnet
- NSERC Industrial Chair on Drinking Water, Department of Civil, Geological, and Mining Engineering, Polytechnique Montréal, QC, H3C 3A7, Canada; Canada Research Chair in Source Water Protection, Department of Civil, Geological, and Mining Engineering, Polytechnique Montréal, QC, H3C 3A7, Canada
| | - Émile Sylvestre
- NSERC Industrial Chair on Drinking Water, Department of Civil, Geological, and Mining Engineering, Polytechnique Montréal, QC, H3C 3A7, Canada; Canada Research Chair in Source Water Protection, Department of Civil, Geological, and Mining Engineering, Polytechnique Montréal, QC, H3C 3A7, Canada
| | - Sung Vo Duy
- Department of Chemistry, Université de Montréal, P.O. Box 6128, Succ, Centre-Ville, Montréal, QC H3C 3J7, Canada
| | - Richard Villemur
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique, 531 Boulevard des Prairies, Laval, QC H7V 1B7, Canada
| | - Sébastien Sauvé
- Department of Chemistry, Université de Montréal, P.O. Box 6128, Succ, Centre-Ville, Montréal, QC H3C 3J7, Canada
| | - Michèle Prévost
- NSERC Industrial Chair on Drinking Water, Department of Civil, Geological, and Mining Engineering, Polytechnique Montréal, QC, H3C 3A7, Canada
| | - Judy Y Qiu
- Department of Laboratory Medicine and Pathology, University of Alberta, 116th & 85 Ave, Edmonton, AB T6G 2R3, Canada
| | - Xiaoli Pang
- Department of Laboratory Medicine and Pathology, University of Alberta, 116th & 85 Ave, Edmonton, AB T6G 2R3, Canada
| | - Sarah Dorner
- Canada Research Chair in Source Water Protection, Department of Civil, Geological, and Mining Engineering, Polytechnique Montréal, QC, H3C 3A7, Canada
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2
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Liu Z, Lin Y, Ge Y, Zhu Z, Yuan J, Yin Q, Liu B, He K, Hu M. Meta-analysis of microbial source tracking for the identification of fecal contamination in aquatic environments based on data-mining. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 345:118800. [PMID: 37591102 DOI: 10.1016/j.jenvman.2023.118800] [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: 06/08/2023] [Revised: 07/29/2023] [Accepted: 08/10/2023] [Indexed: 08/19/2023]
Abstract
Microbial source tracking (MST) technology represents an innovative approach employed to trace fecal contamination in environmental water systems. The performance of primers may be affected by amplification techniques, target primer categories, and regional differences. To investigate the influence of these factors on primer recognition performance, a meta-analysis was conducted on the application of MST in water environments using three databases: Web of Science, Scopus, and PubMed (n = 2291). After data screening, 46 studies were included in the final analysis. The investigation encompassed Polymerase Chain Reaction (PCR)/quantitative PCR (qPCR) methodologies, dye-based (SYBR)/probe-based (TaqMan) techniques, and geographical differences of a human host-specific (HF183) primer and other 21 additional primers. The results indicated that the primers analyzed were capable of differentiating host specificity to a certain degree. Nonetheless, by comparing sensitivity and specificity outcomes, it was observed that virus-based primers exhibited superior specificity and recognition capacity, as well as a stronger correlation with human pathogenicity in water environments compared to bacteria-based primers. This finding highlights an important direction for future advancements. Moreover, within the same category, qPCR did not demonstrate significant benefits over conventional PCR amplification methods. In comparing dye-based and probe-based techniques, it was revealed that the probe-based method's advantage lay primarily in specificity, which may be associated with the increased propensity of dye-based methods to produce false positives. Furthermore, the heterogeneity of the HF183 primer was not detected in China, Canada, and Singapore respectively, indicating a low likelihood of regional differences. The variation among the 21 other primers may be attributable to regional differences, sample sources, detection techniques, or alternative factors. Finally, we identified that economic factors, climatic conditions, and geographical distribution significantly influence primer performance.
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Affiliation(s)
- Zejun Liu
- School of Civil Engineering, Sun Yat-Sen University, Zhuhai, 519082, China; Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510070, China
| | - Yingying Lin
- School of Civil Engineering, Sun Yat-Sen University, Zhuhai, 519082, China
| | - Yanhong Ge
- Guangdong Infore Technology Co., Ltd, Foshan, 528322, China
| | - Ziyue Zhu
- School of Civil Engineering, Sun Yat-Sen University, Zhuhai, 519082, China
| | - Jinlong Yuan
- School of Civil Engineering, Sun Yat-Sen University, Zhuhai, 519082, China
| | - Qidong Yin
- School of Civil Engineering, Sun Yat-Sen University, Zhuhai, 519082, China
| | - Bingjun Liu
- School of Civil Engineering, Sun Yat-Sen University, Zhuhai, 519082, China
| | - Kai He
- School of Civil Engineering, Sun Yat-Sen University, Zhuhai, 519082, China.
| | - Maochuan Hu
- School of Civil Engineering, Sun Yat-Sen University, Zhuhai, 519082, China; Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510070, China.
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3
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Flores ME, Jafarzadeh A, Moghadam SV, Vadde KK, Dhar DA, Nunu RR, Kapoor V. Occurrence and removal of fecal bacteria and microbial source tracking markers in a stormwater detention basin overlying the Edwards Aquifer recharge zone in Texas. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:103836-103850. [PMID: 37691063 DOI: 10.1007/s11356-023-29636-w] [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: 04/19/2023] [Accepted: 08/28/2023] [Indexed: 09/12/2023]
Abstract
The Edwards Aquifer is the primary water resource for over 2 million people in Texas and faces challenges including fecal contamination of water recharging the aquifer, while effectiveness of best management practices (BMPs) such as detention basins in mitigating fecal pollution remains poorly understood. For this study, the inlet and outlet of a detention basin overlying the aquifer's recharge zone were sampled following storm events using automated samplers. Microbial source tracking and culture-based methods were used to determine the occurrence and removal of fecal genetic markers and fecal coliform bacteria in collected water samples. Markers included E. coli (EC23S857), Enterococcus (Entero1), human (HF183), canine (BacCan), and bird (GFD). Fecal coliforms, EC23S857, and Entero1 were detected following each storm event. GFD was the most frequent host-associated marker detected (91% of samples), followed by BacCan (46%), and HF183 (17%). Wilcoxon signed rank tests indicated significantly lower outlet concentrations for fecal coliforms, EC23S857, and Entero1, but not for HF183, GFD, and BacCan. Higher GFD and BacCan outlet concentrations may be due to factors independent of basin design, such as the non-point source nature of bird fecal contamination and domestic dog care practices in neighborhoods contributing to the basin. Mann-Whitney tests showed marker concentrations were not significantly higher during instances of fecal coliform water quality criterion exceedance, except for E. coli, and that fecal coliform concentrations were not significantly different based on marker detection. Overall, results suggest that the detention basin is effective in attenuating fecal contamination associated with fecal coliforms and the general markers, but not for host-associated markers. Consequently, management efforts should focus on mitigating dog and bird-associated fecal pollution in the study region.
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Affiliation(s)
- Mauricio Eduardo Flores
- School of Civil & Environmental Engineering, and Construction Management, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA
- Southwest Research Institute, 6220 Culebra Rd, San Antonio, TX, 78238, USA
| | - Arash Jafarzadeh
- School of Civil & Environmental Engineering, and Construction Management, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA
| | - Sina Vedadi Moghadam
- School of Civil & Environmental Engineering, and Construction Management, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA
| | - Kiran Kumar Vadde
- School of Civil & Environmental Engineering, and Construction Management, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA
| | - Dipti Anik Dhar
- School of Civil & Environmental Engineering, and Construction Management, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA
| | - Rebecca R Nunu
- Southwest Research Institute, 6220 Culebra Rd, San Antonio, TX, 78238, USA
| | - Vikram Kapoor
- School of Civil & Environmental Engineering, and Construction Management, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA.
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VanMensel D, Chaganti SR, Droppo IG, Weisener CG. Microbe-sediment interactions in Great Lakes recreational waters: Implications for human health risk. Environ Microbiol 2023; 25:1605-1623. [PMID: 36998158 DOI: 10.1111/1462-2920.16378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 03/19/2023] [Indexed: 04/01/2023]
Abstract
Microbial assessments of recreational water have traditionally focused on culturing or DNA-based approaches of the planktonic water column, omitting influence from microbe-sediment relationships. Sediment (bed and suspended) has been shown to often harbour levels of bacteria higher than the planktonic phase. The fate of suspended sediment (SS) bacteria is extensively related to transport dynamics (e.g., deposition) of the associated sediment/floc. When hydraulic energy allows, SS will settle, introducing new (potentially pathogenic) organisms to the bed. With turbulence, including waves, currents and swimmers, the risk of human ingestion is elevated due to resuspension of bed sediment and associated microbes. This research used multiplex nanofluidic reverse transcriptase quantitative PCR on RNA of bacteria associated with bed and SS to explore the active bacteria in freshwater shorelines. Bacterial genes of human health concern regarding recreational water use were targeted, such as faecal indicator bacteria (FIB), microbial source tracking genes and virulence factors from waterborne pathogens. Results indicate avian sources (i.e., gulls, geese) to be the largest nonpoint source of FIB associated with sediment in Great Lakes shorelines. This research introduces a novel approach to microbial water quality assessments and enhances our understanding of microbe-sediment dynamics and the quality of freshwater beaches.
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Affiliation(s)
- Danielle VanMensel
- Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Avenue, N9B 3P4, Windsor, Ontario, Canada
| | - Subba Rao Chaganti
- Cooperative Institute for Great Lakes Research, University of Michigan, 4840 South State Street, Ann Arbor, Michigan, 48108, USA
| | - Ian G Droppo
- Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Avenue, N9B 3P4, Windsor, Ontario, Canada
| | - Christopher G Weisener
- Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Avenue, N9B 3P4, Windsor, Ontario, Canada
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5
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Vadde KK, Phan DC, Moghadam SV, Jafarzadeh A, Matta A, Johnson D, Kapoor V. Fecal pollution source characterization in the surface waters of recharge and contributing zones of a karst aquifer using general and host-associated fecal genetic markers. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:2450-2464. [PMID: 36444711 DOI: 10.1039/d2em00418f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Fecal pollution of surface waters in the karst-dominated Edwards aquifer is a serious concern as contaminated waters can rapidly transmit to groundwaters, which are used for domestic purposes. Although microbial source tracking (MST) detects sources of fecal pollution, integrating data related to environmental processes (precipitation) and land management practices (septic tanks) with MST can provide better understanding of fecal contamination fluxes to implement effective mitigation strategies. Here, we investigated fecal sources and their spatial origins at recharge and contributing zones of the Edwards aquifer and identified their relationship with nutrients in different environmental/land-use conditions. During March 2019 to March 2020, water samples (n = 295) were collected biweekly from 11 sampling sites across four creeks and analyzed for six physico-chemical parameters and ten fecal indicator bacteria (FIB) and MST-based qPCR assays targeting general (E. coli, Enterococcus, and universal Bacteroidales), human (BacHum and HF183), ruminant (Rum2Bac), cattle (BacCow), canine (BacCan), and avian (Chicken/Duck-Bac and GFD) fecal markers. Among physico-chemical parameters, nitrate-N (NO3-N) concentrations at several sites were higher than estimated national background concentrations for streams. General fecal markers were detected in the majority of water samples, and among host-associated MST markers, GFD, BacCow, and Rum2Bac were more frequently detected than BacCan, BacHum, and HF183, indicating avian and ruminant fecal contamination is a major concern. Cluster analysis results indicated that sampling sites clustered based on precipitation and septic tank density showed significant correlation (p < 0.05) between nutrients and FIB/MST markers, indicating these factors are influencing the spatial and temporal variations of fecal sources. Overall, results emphasize that integration of environmental/land-use data with MST is crucial for a better understanding of nutrient loading and fecal contamination.
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Affiliation(s)
- Kiran Kumar Vadde
- School of Civil & Environmental Engineering, and Construction Management, University of Texas at San Antonio, San Antonio, TX 78249, USA.
| | - Duc C Phan
- School of Civil & Environmental Engineering, and Construction Management, University of Texas at San Antonio, San Antonio, TX 78249, USA.
| | - Sina V Moghadam
- School of Civil & Environmental Engineering, and Construction Management, University of Texas at San Antonio, San Antonio, TX 78249, USA.
| | - Arash Jafarzadeh
- School of Civil & Environmental Engineering, and Construction Management, University of Texas at San Antonio, San Antonio, TX 78249, USA.
| | - Akanksha Matta
- School of Civil & Environmental Engineering, and Construction Management, University of Texas at San Antonio, San Antonio, TX 78249, USA.
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Drew Johnson
- School of Civil & Environmental Engineering, and Construction Management, University of Texas at San Antonio, San Antonio, TX 78249, USA.
| | - Vikram Kapoor
- School of Civil & Environmental Engineering, and Construction Management, University of Texas at San Antonio, San Antonio, TX 78249, USA.
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Zhu K, Suttner B, Knee J, Capone D, Moe CL, Stauber CE, Konstantinidis KT, Wallach TE, Pickering AJ, Brown J. Elevated Fecal Mitochondrial DNA from Symptomatic Norovirus Infections Suggests Potential Health Relevance of Human Mitochondrial DNA in Fecal Source Tracking. ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS 2022; 9:543-550. [PMID: 35719858 PMCID: PMC9202355 DOI: 10.1021/acs.estlett.2c00140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 06/15/2023]
Abstract
An end goal of fecal source tracking (FST) is to provide information on risk of transmission of waterborne illnesses associated with fecal contamination. Ideally, concentrations of FST markers in ambient waters would reflect exposure risk. Human mtDNA is an FST marker that is exclusively human in origin and may be elevated in feces of individuals experiencing gastrointestinal inflammation. In this study, we examined whether human mtDNA is elevated in fecal samples from individuals with symptomatic norovirus infections using samples from the United States (US), Mozambique, and Bangladesh. We quantified hCYTB484 (human mtDNA) and HF183/BacR287 (human-associated Bacteroides) FST markers using droplet digital polymerase chain reaction. We observed the greatest difference in concentrations of hCYTB484 when comparing samples from individuals with symptomatic norovirus infections versus individuals without norovirus infections or diarrhea symptoms: log10 increase of 1.42 in US samples (3,820% increase, p-value = 0.062), 0.49 in Mozambique (308% increase, p-value = 0.061), and 0.86 in Bangladesh (648% increase, p-value = 0.035). We did not observe any trends in concentrations of HF183/BacR287 in the same samples. These results suggest concentrations of fecal mtDNA may increase during symptomatic norovirus infection and that mtDNA in environmental samples may represent an unambiguously human source-tracking marker that correlates with enteric pathogen exposure risk.
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Affiliation(s)
- Kevin
J. Zhu
- School
of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Brittany Suttner
- School
of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Jackie Knee
- Department
of Disease Control, London School of Hygiene
and Tropical Medicine, London WC1E 7HT,United Kingdom
| | - Drew Capone
- Department
of Environmental Sciences and Engineering, Gillings School of Global
Public Health, University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina 27599, United States
| | - Christine L. Moe
- Center
for Global Safe Water, Sanitation, and Hygiene, Rollins School of
Public Health, Emory University, Atlanta, Georgia 30322, United States
| | - Christine E. Stauber
- Department
of Population Health Sciences, School of Public Health, Georgia State University, Atlanta, Georgia 30302, United States
| | - Kostas T. Konstantinidis
- School
of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Thomas E. Wallach
- Division
of Pediatric Gastroenterology, SUNY Downstate
Health Sciences University, Brooklyn, New York 11203, United States
| | - Amy J. Pickering
- Department
of Civil and Environmental Engineering, University of California, Berkeley, California 94720, United States
| | - Joe Brown
- Department
of Environmental Sciences and Engineering, Gillings School of Global
Public Health, University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina 27599, United States
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Ragot R, Villemur R. eDNA profiling of mammals, birds, and fish of surface waters by mitochondrial metagenomics: application for source tracking of fecal contamination in surface waters. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:72. [PMID: 34997305 DOI: 10.1007/s10661-021-09668-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 11/27/2021] [Indexed: 06/14/2023]
Abstract
Knowing the composition of animals present in aquatic ecosystems can tell us about the anthropic pressures on these environments. One of these pressures is the occurrence of fecal contamination. However, this contamination can originate from more than one animal species in areas where urban and agricultural activities overlap. Mitochondrial DNA (mtDNA) has become the standard barcoding tool to identify the presence of animal species in environment. Amplicon-sequencing metagenomics is a powerful approach to derive the animal profile in an environment. However, PCR primers targeting mtDNA of a broad range of animals are highly degenerate or generate short DNA fragments that could cause ambiguous affiliation. Here we report the development of a new set of primers targeting the mitochondrial 16S ribosomal RNA genes of a broad range of terrestrial and aquatic animals, which include mammals, birds, and fishes. These primers successfully amplified mtDNA from environmental DNA (eDNA) extracted from surface waters. Sequencing the resulting amplicons revealed the presence of mammals and birds that may contribute in fecal contamination of surface water. In one of the river samples high in fecal indicator bacteria, human and bovine mtDNA accounted for 40.5% and 4.1% of the sequences, respectively, suggesting fecal contamination by these two animals. These findings indicate that our PCR primers coupled with amplicon-sequencing metagenomics contribute in profiling the animal diversity in the surface waters and its surrounding. This approach could be a valuable tool to identify simultaneously the potential contribution of various animals as sources of fecal contamination in surface waters.
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Affiliation(s)
- Rose Ragot
- INRS Centre Armand-Frappier Santé Biotechnologie, 531 Boulevard des Prairies, Laval, QC, H7V 1B7, Canada
| | - Richard Villemur
- INRS Centre Armand-Frappier Santé Biotechnologie, 531 Boulevard des Prairies, Laval, QC, H7V 1B7, Canada.
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Abstract
Tropical Storm Imelda struck the southeast coastal regions of Texas from 17–19 September, 2019, and delivered precipitation above 500 mm over about 6000 km2. The performance of the three IMERG (Early-, Late-, and Final-run) GPM satellite-based precipitation products was evaluated against Stage-IV radar precipitation estimates. Basic and probabilistic statistical metrics, such as CC, RSME, RBIAS, POD, FAR, CSI, and PSS were employed to assess the performance of the IMERG products. The products captured the event adequately, with a fairly high POD value of 0.9. The best product (Early-run) showed an average correlation coefficient of 0.60. The algorithm used to produce the Final-run improved the quality of the data by removing systematic errors that occurred in the near-real-time products. Less than 5 mm RMSE error was experienced in over three-quarters (ranging from 73% to 76%) of the area by all three IMERG products in estimating the Tropical Storm Imelda. The Early-run product showed a much better RBIAS relatively to the Final-run product. The overall performance was poor, as areas with an acceptable range of RBIAS (i.e., between −10% and 10%) in all the three IMERG products were only 16% to 17% of the total area. Overall, the Early-run product was found to be better than Late- and Final-run.
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Hinojosa J, Green J, Estrada F, Herrera J, Mata T, Phan D, Pasha ABMT, Matta A, Johnson D, Kapoor V. Determining the primary sources of fecal pollution using microbial source tracking assays combined with land-use information in the Edwards Aquifer. WATER RESEARCH 2020; 184:116211. [PMID: 32721766 DOI: 10.1016/j.watres.2020.116211] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 07/18/2020] [Accepted: 07/20/2020] [Indexed: 06/11/2023]
Abstract
The Edwards Aquifer serves as a primary source of drinking water to more than 2 million people in south-central Texas, and as a karst aquifer, is vulnerable to human and animal fecal contamination which poses a serious risk to human and environmental health. A one-year study (Jan 2018 - Feb 2019) was conducted to determine the primary sources of fecal pollution along the Balcones and Leon Creek within the Edwards Aquifer recharge and contributing zones using general (E. coli, enterococci, and universal Bacteriodales) and host-associated (human-, dog-, cow- and chicken/duck-associated Bacteriodales) microbial source tracking (MST) assays. Additionally, sites were classified based on surrounding land use as a potential source predictor and marker levels were correlated with rain events and water quality parameters. Levels for the three general indicators were highest and exhibited similar trends across the sampling sites, suggesting that the sole use of these markers is not sufficient for specific fecal source identification. Among the host-associated markers, highest concentrations were observed for the dog marker (BacCan) in the Leon Creek area and the cow marker (BacCow) in the Balcones Creek area. Additionally, Chicken/Duck-Bac, BacCan and BacCow all exhibited higher concentrations during the spring season and the end of fall/early winter. Relatively lower concentrations were observed for the human-associated markers (HF183 and BacHum), however, levels were higher in the Leon Creek area and highest following rainfall events. Additionally, relatively higher levels in HF183 and BacHum were observed at sites having greater human population and septic tank density and may be attributed to leaks or breaks in these infrastructures. This study is the first to examine and compare fecal contamination at rural and urban areas in the recharge and contributing zones of the Edwards Aquifer using a molecular MST approach targeting Bacteroidales 16S rRNA gene-based assays. The Bacteroidales marker assays, when combined with land use and weather information, can allow for a better understanding of the sources and fluxes of fecal contamination, which can help devise effective mitigation measures to protect water quality.
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Affiliation(s)
- Jessica Hinojosa
- Department of Civil and Environmental Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Jemima Green
- Department of Civil and Environmental Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Fabiola Estrada
- Department of Civil and Environmental Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Jonathan Herrera
- Department of Civil and Environmental Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Troy Mata
- Department of Civil and Environmental Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Duc Phan
- Department of Civil and Environmental Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - A B M Tanvir Pasha
- Department of Civil and Environmental Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Akanksha Matta
- Department of Civil and Environmental Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Drew Johnson
- Department of Civil and Environmental Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Vikram Kapoor
- Department of Civil and Environmental Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA.
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