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de Brito Cruz D, Schmidt PJ, Emelko MB. Drinking water QMRA and decision-making: Sensitivity of risk to common independence assumptions about model inputs. WATER RESEARCH 2024; 259:121877. [PMID: 38870891 DOI: 10.1016/j.watres.2024.121877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 05/31/2024] [Accepted: 06/02/2024] [Indexed: 06/15/2024]
Abstract
When assessing risk posed by waterborne pathogens in drinking water, it is common to use Monte Carlo simulations in Quantitative Microbial Risk Assessment (QMRA). This method accounts for the variables that affect risk and their different values in a given system. A common underlying assumption in such analyses is that all random variables are independent (i.e., one is not associated in any way with another). Although the independence assumption simplifies the analysis, it is not always correct. For example, treatment efficiency can depend on microbial concentrations if changes in microbial concentrations either affect treatment themselves or are associated with water quality changes that affect treatment (e.g., during/after climate shocks like extreme precipitation events or wildfires). Notably, the effects of erroneous assumptions of independence in QMRA have not been widely discussed. Due to the implications of drinking water safety decisions on public health protection, it is critical that risk models accurately reflect the context being studied to meaningfully support decision-making. This work illustrates how dependence between pathogen concentration and either treatment efficiency or water consumption can impact risk estimates using hypothetical scenarios of relevance to drinking water QMRA. It is shown that the mean and variance of risk estimates can change substantially with different degrees of correlation. Data from a water supply system in Calgary, Canada are also used to illustrate the effect of dependence on risk. Recognizing the difficulty of obtaining data to empirically assess dependence, a framework to guide evaluation of the effect of dependence is presented to enhance support for decision making. This work emphasizes the importance of acknowledging and discussing assumptions implicit to models.
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Affiliation(s)
- Dafne de Brito Cruz
- Department of Civil and Environmental Engineering, University of Waterloo, 200 University Ave. W, Waterloo, Ontario N2L 3G1, Canada.
| | - Philip J Schmidt
- Department of Civil and Environmental Engineering, University of Waterloo, 200 University Ave. W, Waterloo, Ontario N2L 3G1, Canada.
| | - Monica B Emelko
- Department of Civil and Environmental Engineering, University of Waterloo, 200 University Ave. W, Waterloo, Ontario N2L 3G1, Canada.
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Glassmeyer ST, Burns EE, Focazio MJ, Furlong ET, Gribble MO, Jahne MA, Keely SP, Kennicutt AR, Kolpin DW, Medlock Kakaley EK, Pfaller SL. Water, Water Everywhere, but Every Drop Unique: Challenges in the Science to Understand the Role of Contaminants of Emerging Concern in the Management of Drinking Water Supplies. GEOHEALTH 2023; 7:e2022GH000716. [PMID: 38155731 PMCID: PMC10753268 DOI: 10.1029/2022gh000716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 09/21/2023] [Accepted: 09/21/2023] [Indexed: 12/30/2023]
Abstract
The protection and management of water resources continues to be challenged by multiple and ongoing factors such as shifts in demographic, social, economic, and public health requirements. Physical limitations placed on access to potable supplies include natural and human-caused factors such as aquifer depletion, aging infrastructure, saltwater intrusion, floods, and drought. These factors, although varying in magnitude, spatial extent, and timing, can exacerbate the potential for contaminants of concern (CECs) to be present in sources of drinking water, infrastructure, premise plumbing and associated tap water. This monograph examines how current and emerging scientific efforts and technologies increase our understanding of the range of CECs and drinking water issues facing current and future populations. It is not intended to be read in one sitting, but is instead a starting point for scientists wanting to learn more about the issues surrounding CECs. This text discusses the topical evolution CECs over time (Section 1), improvements in measuring chemical and microbial CECs, through both analysis of concentration and toxicity (Section 2) and modeling CEC exposure and fate (Section 3), forms of treatment effective at removing chemical and microbial CECs (Section 4), and potential for human health impacts from exposure to CECs (Section 5). The paper concludes with how changes to water quantity, both scarcity and surpluses, could affect water quality (Section 6). Taken together, these sections document the past 25 years of CEC research and the regulatory response to these contaminants, the current work to identify and monitor CECs and mitigate exposure, and the challenges facing the future.
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Affiliation(s)
- Susan T. Glassmeyer
- U.S. Environmental Protection AgencyOffice of Research and DevelopmentCincinnatiOHUSA
| | | | - Michael J. Focazio
- Retired, Environmental Health ProgramEcosystems Mission AreaU.S. Geological SurveyRestonVAUSA
| | - Edward T. Furlong
- Emeritus, Strategic Laboratory Sciences BranchLaboratory & Analytical Services DivisionU.S. Geological SurveyDenverCOUSA
| | - Matthew O. Gribble
- Gangarosa Department of Environmental HealthRollins School of Public HealthEmory UniversityAtlantaGAUSA
| | - Michael A. Jahne
- U.S. Environmental Protection AgencyOffice of Research and DevelopmentCincinnatiOHUSA
| | - Scott P. Keely
- U.S. Environmental Protection AgencyOffice of Research and DevelopmentCincinnatiOHUSA
| | - Alison R. Kennicutt
- Department of Civil and Mechanical EngineeringYork College of PennsylvaniaYorkPAUSA
| | - Dana W. Kolpin
- U.S. Geological SurveyCentral Midwest Water Science CenterIowa CityIAUSA
| | | | - Stacy L. Pfaller
- U.S. Environmental Protection AgencyOffice of Research and DevelopmentCincinnatiOHUSA
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3
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Jahne MA, Schoen ME, Kaufmann A, Pecson BM, Olivieri A, Sharvelle S, Anderson A, Ashbolt NJ, Garland JL. Enteric pathogen reduction targets for onsite non-potable water systems: A critical evaluation. WATER RESEARCH 2023; 233:119742. [PMID: 36848851 PMCID: PMC10084472 DOI: 10.1016/j.watres.2023.119742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 02/10/2023] [Accepted: 02/11/2023] [Indexed: 06/18/2023]
Abstract
Onsite non-potable water systems (ONWS) collect and treat local source waters for non-potable end uses such as toilet flushing and irrigation. Quantitative microbial risk assessment (QMRA) has been used to set pathogen log10-reduction targets (LRTs) for ONWS to achieve the risk benchmark of 10-4 infections per person per year (ppy) in a series of two efforts completed in 2017 and 2021. In this work, we compare and synthesize the ONWS LRT efforts to inform the selection of pathogen LRTs. For onsite wastewater, greywater, and stormwater, LRTs for human enteric viruses and parasitic protozoa were within 1.5-log10 units between 2017 and 2021 efforts, despite differences in approaches used to characterize pathogens in these waters. For onsite wastewater and greywater, the 2017 effort used an epidemiology-based model to simulate pathogen concentrations contributed exclusively from onsite waste and selected Norovirus as the viral reference pathogen; the 2021 effort used municipal wastewater pathogen data and cultivable adenoviruses as the reference viral pathogen. Across source waters, the greatest differences occurred for viruses in stormwater, given the newly available municipal wastewater characterizations used for modeling sewage contributions in 2021 and the different selection of reference pathogens (Norovirus vs. adenoviruses). The roof runoff LRTs support the need for protozoa treatment, but these remain difficult to characterize due to the pathogen variability in roof runoff across space and time. The comparison highlights adaptability of the risk-based approach, allowing for updated LRTs as site specific or improved information becomes available. Future research efforts should focus on data collection of onsite water sources.
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Affiliation(s)
- Michael A Jahne
- Office of Research and Development, U.S. Environmental Protection Agency, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, USA.
| | - Mary E Schoen
- Soller Environmental, LLC, 3022 King St., Berkeley, CA 94703, USA
| | - Anya Kaufmann
- Trussell Technologies, Inc., 1939 Harrison St., Oakland, CA 94612, USA
| | - Brian M Pecson
- Trussell Technologies, Inc., 1939 Harrison St., Oakland, CA 94612, USA
| | | | - Sybil Sharvelle
- Colorado State University, Department of Civil and Environmental Engineering, 1372 Campus Delivery, Fort Collins, CO 80523, USA
| | - Anita Anderson
- Minnesota Department of Health, 625 Robert St. N, St. Paul, MN 55164, USA
| | | | - Jay L Garland
- Office of Research and Development, U.S. Environmental Protection Agency, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, USA
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Latchmore T, Lavallee S, Hynds PD, Brown RS, Majury A. Integrating consumer risk perception and awareness with simulation-based quantitative microbial risk assessment using a coupled systems framework: A case study of private groundwater users in Ontario. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 331:117112. [PMID: 36681033 DOI: 10.1016/j.jenvman.2022.117112] [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: 10/21/2022] [Revised: 11/23/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
Private well users in Ontario are responsible for ensuring the potability of their own private drinking water source through protective actions (i.e., water treatment, well maintenance, and regular water quality testing). In the absence of regulation and limited surveillance, quantitative microbial risk assessment (QMRA) represents the most practical and robust approach to estimating the human health burden attributable to private wells. For an increasingly accurate estimation, QMRA of private well water should be represented by a coupled model, which includes both the socio-cognitive and physical aspects of private well water contamination and microbial exposure. The objective of the current study was to determine levels of waterborne exposure via well water consumption among three sub-groups (i.e., clusters) of private well users in Ontario and quantify the risk of waterborne acute gastrointestinal illness (AGI) attributed to Giardia, shiga-toxin producing E. coli (STEC) and norovirus from private drinking water sources in Ontario. Baseline simulations were utilized to explore the effect of varying socio-cognitive scenarios on model inputs (i.e., increased awareness, protective actions, aging population). The current study uses a large spatio-temporal groundwater quality dataset and cross-sectional province-wide survey to create socio-cognitive-specific QMRA simulations to estimate the risk of waterborne AGI attributed to three enteric pathogens in private drinking waters source in Ontario. Findings suggest significant differences in the level of exposure among sub-groups of private well users. Private well users within Cluster 3 are characterised by higher levels of exposure and annual illness attributable to STEC, Giardia and norovirus than Clusters 1 and 2. Provincial incidence rates of 520.9 (1522 illness per year), 532.1 (2211 illness per year) and 605.5 (5345 illness per year) cases/100,000 private well users per year were predicted for private well users associated with Clusters 1 through 3. Established models will enable development of necessary tools tailored to specific groups of at-risk well users, allowing for preventative public health management of private groundwater sources.
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Affiliation(s)
- Tessa Latchmore
- School of Environmental Studies, Queen's University, Kingston, Ontario, Canada
| | - Sarah Lavallee
- School of Environmental Studies, Queen's University, Kingston, Ontario, Canada
| | - Paul D Hynds
- Environmental Sustainability and Health Institute, Technological University Dublin, Dublin, Ireland.
| | - R Stephen Brown
- School of Environmental Studies, Queen's University, Kingston, Ontario, Canada
| | - Anna Majury
- School of Environmental Studies, Queen's University, Kingston, Ontario, Canada; Public Health Ontario, Kingston, Ontario, Canada.
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González-Fernández A, Symonds EM, Gallard-Gongora JF, Mull B, Lukasik JO, Rivera Navarro P, Badilla Aguilar A, Peraud J, Mora Alvarado D, Cantor A, Breitbart M, Cairns MR, Harwood VJ. Risk of Gastroenteritis from Swimming at a Wastewater-Impacted Tropical Beach Varies across Localized Scales. Appl Environ Microbiol 2023; 89:e0103322. [PMID: 36847564 PMCID: PMC10057883 DOI: 10.1128/aem.01033-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 01/21/2023] [Indexed: 03/01/2023] Open
Abstract
Population growth and changing climate are expected to increase human exposure to pathogens in tropical coastal waters. We examined microbiological water quality in three rivers within 2.3 km of each other that impact a Costa Rican beach and in the ocean outside their plumes during the rainy and dry seasons. We performed quantitative microbial risk assessment (QMRA) to predict the risk of gastroenteritis associated with swimming and the amount of pathogen reduction needed to achieve safe conditions. Recreational water quality criteria based on enterococci were exceeded in >90% of river samples but in only 13% of ocean samples. Multivariate analysis grouped microbial observations by subwatershed and season in river samples but only by subwatershed in the ocean. The modeled median risk from all pathogens in river samples was between 0.345 and 0.577, 10-fold above the U.S. Environmental Protection Agency (U.S. EPA) benchmark of 0.036 (36 illnesses/1,000 swimmers). Norovirus genogroup I (NoVGI) contributed most to risk, but adenoviruses raised risk above the threshold in the two most urban subwatersheds. The risk was greater in the dry compared to the rainy season, due largely to the greater frequency of NoVGI detection (100% versus 41%). Viral log10 reduction needed to ensure safe swimming conditions varied by subwatershed and season and was greatest in the dry season (3.8 to 4.1 dry; 2.7 to 3.2 rainy). QMRA that accounts for seasonal and local variability of water quality contributes to understanding the complex influences of hydrology, land use, and environment on human health risk in tropical coastal areas and can contribute to improved beach management. IMPORTANCE This holistic investigation of sanitary water quality at a Costa Rican beach assessed microbial source tracking (MST) marker genes, pathogens, and indicators of sewage. Such studies are still rare in tropical climates. Quantitative microbial risk assessment (QMRA) found that rivers impacting the beach consistently exceeded the U.S. EPA risk threshold for gastroenteritis of 36/1,000 swimmers. The study improves upon many QMRA studies by measuring specific pathogens, rather than relying on surrogates (indicator organisms or MST markers) or estimating pathogen concentrations from the literature. By analyzing microbial levels and estimating the risk of gastrointestinal illness in each river, we were able to discern differences in pathogen levels and human health risks even though all rivers were highly polluted by wastewater and were located less than 2.5 km from one another. This variability on a localized scale has not, to our knowledge, previously been demonstrated.
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Affiliation(s)
| | - Erin M. Symonds
- College of Marine Science, University of South Florida, Saint Petersburg, Florida, USA
- Department of Anthropology, Southern Methodist University, Dallas, Texas, USA
| | | | - Bonnie Mull
- BCS Laboratories, Inc., Gainesville, Florida, USA
| | | | - Pablo Rivera Navarro
- Laboratorio Nacional de Aguas, Instituto Costarricense de Acueductos y Alcantarillados, Tres Ríos, Cartago, Costa Rica
| | - Andrei Badilla Aguilar
- Laboratorio Nacional de Aguas, Instituto Costarricense de Acueductos y Alcantarillados, Tres Ríos, Cartago, Costa Rica
| | - Jayme Peraud
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Darner Mora Alvarado
- Laboratorio Nacional de Aguas, Instituto Costarricense de Acueductos y Alcantarillados, Tres Ríos, Cartago, Costa Rica
| | - Allison Cantor
- Department of Anthropology, Southern Methodist University, Dallas, Texas, USA
| | - Mya Breitbart
- College of Marine Science, University of South Florida, Saint Petersburg, Florida, USA
| | - Maryann R. Cairns
- Department of Anthropology, Southern Methodist University, Dallas, Texas, USA
| | - Valerie J. Harwood
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
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6
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Ma D, Weir MH, Hull NM. Fluence-based QMRA model for bacterial photorepair and regrowth in drinking water after decentralized UV disinfection. WATER RESEARCH 2023; 231:119612. [PMID: 36706469 DOI: 10.1016/j.watres.2023.119612] [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: 07/26/2022] [Revised: 12/19/2022] [Accepted: 01/13/2023] [Indexed: 06/18/2023]
Abstract
Ultraviolet disinfection is a promising solution for decentralized drinking water systems such as communal water taps. A potential health risk is enzymatic photorepair of pathogens after UV disinfection, which can result in regrowth of pathogens. Even though photorepair is a known issue, no formal risk assessments have been conducted for photorepair after UV disinfection in drinking water. The main objective was to construct a quantitative microbial risk assessment (QMRA) of photorepair after UV disinfection of drinking water in a decentralized system. UV disinfection and photorepair kinetics for E. coli were modelled using reproducible fluence-based determinations. Impacts of water collection patterns, and wavelength-dependent water container material transmittance, sunlight intensity, and photorepair enzyme absorbance were quantified. After UV disinfection by 16 or 40 mJ/cm2 of < 5-log microorganisms per L, risk of infection did not exceed 1-in-10,000 under conditions permitting E. coli photorepair. Risk from photorepair was less than 1-in-10,000 for photorepair light exposure < 0.75 h throughout the day for UV fluence 16 mJ/cm2 or greater. UV disinfection followed by solar disinfection surpassing photoreactivation during storage reduced risk below 1-in-10,000 for photorepair light exposure > 2.5 h between modelled times of 9 AM - 3 PM. The model can be expanded to other pathogens as UV fluence and photorepair fluence response kinetics become available, and this QMRA can be used to inform the placement of community water access points to reduce risk of photorepair and ensure adequate shelf life of UV disinfected water under safe storage conditions.
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Affiliation(s)
- Daniel Ma
- College of Engineering, Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Mark H Weir
- Division of Environmental Health Sciences, College of Public Health, The Ohio State University, Columbus, OH 43210, USA; Sustainability Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Natalie M Hull
- College of Engineering, Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, Columbus, OH 43210, USA; Sustainability Institute, The Ohio State University, Columbus, OH 43210, USA.
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Assessing the risk of acute gastrointestinal illness attributable to three enteric pathogens from contaminated private water wells in Ontario. Int J Hyg Environ Health 2023; 248:114077. [PMID: 36462411 DOI: 10.1016/j.ijheh.2022.114077] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 10/28/2022] [Accepted: 11/15/2022] [Indexed: 12/03/2022]
Abstract
The province of Ontario compromises the largest groundwater reliant population in Canada serving approximately 1.6 million individuals. Unlike municipal water systems, private well water is not required to meet water quality regulatory standards and thus source maintenance, treatment and testing remains the responsibility of the well owner. Infections associated with private drinking water systems are rarely documented given their typically sporadic nature, thus the human health effects (e.g., acute gastrointestinal illness (AGI)) on consumers remains relatively unknown, representing a significant gap in water safety management. The current study sought to quantify the risk of waterborne AGI attributed to Giardia, shiga-toxin producing E. coli (STEC) and norovirus from private drinking water sources in Ontario using Monte Carlo simulation-based quantitative microbial risk assessment (QMRA). Findings suggest that consumption of contaminated private well water in Ontario is responsible for approximately 4823 AGI cases annually, with 3464 (71.8%) and 1359 (28.1%) AGI cases predicted to occur in consolidated and unconsolidated aquifers, respectively. By pathogen, waterborne AGI was attributed to norovirus (62%; 2991/4823), Giardia (24.6%; 1186/4823) and STEC (13.4%; 646/4823). The developed QMRA framework was used to assess the potential health impacts of partial and total well water treatment system failure. In the unlikely event of total treatment failure, total mean annual illnesses are predicted to almost double (4217 to 7064 cases per year), highlighting the importance of effective water treatment and comprehensive testing programs in reducing infectious health risks attributable to private well water in Ontario. Study findings indicate significant underreporting of waterborne AGI rates at the provincial level likely biasing public health interventions and programs that are effective in monitoring and minimizing the health risk associated with private well water.
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Rokicka-Konieczna P, Wanag A, Sienkiewicz A, Izuma DS, Ekiert E, Kusiak-Nejman E, Terashima C, Yasumori A, Fujishima A, Morawski AW. Photocatalytic Inactivation of Co-Culture of E. coli and S. epidermidis Using APTES-Modified TiO 2. Molecules 2023; 28:molecules28041655. [PMID: 36838643 PMCID: PMC9965180 DOI: 10.3390/molecules28041655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/01/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
The presented work shows the antibacterial activity of TiO2 photocatalysts modified by 3-aminopropyltriethoxysilane (APTES). The APTES-functionalized TiO2 samples were obtained by the solvothermal process followed by calcination. The antibacterial activity of APTES/TiO2 samples was evaluated with two species of bacteria, Escherichia coli and Staphylococcus epidermidis, under artificial solar light (ASL) irradiation. The used bacteria are model organisms characterized by negative zeta potential (approx. -44.2 mV for E. coli and -42.3 mV for S. epidermidis). For the first time, the antibacterial properties of APTES-functionalized TiO2 were evaluated against mono- and co-cultured bacteria. The high antibacterial properties characterized the obtained APTES-modified nanomaterials. The best antibacterial properties were presented in the TiO2-4 h-120 °C-300 mM-Ar-300 °C sample (modified with 300 mM of APTES and calcined at 300 °C). The improvement of the antibacterial properties was attributed to a positive value of zeta potential, high surface area, and porous volume.
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Affiliation(s)
- Paulina Rokicka-Konieczna
- Department of Inorganic Chemical Technology and Environment Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Pułaskiego 10, 70-322 Szczecin, Poland
- Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
- Correspondence:
| | - Agnieszka Wanag
- Department of Inorganic Chemical Technology and Environment Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Pułaskiego 10, 70-322 Szczecin, Poland
| | - Agnieszka Sienkiewicz
- Department of Inorganic Chemical Technology and Environment Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Pułaskiego 10, 70-322 Szczecin, Poland
| | - Dylan Shun Izuma
- Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Ewa Ekiert
- Department of Inorganic Chemical Technology and Environment Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Pułaskiego 10, 70-322 Szczecin, Poland
| | - Ewelina Kusiak-Nejman
- Department of Inorganic Chemical Technology and Environment Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Pułaskiego 10, 70-322 Szczecin, Poland
| | - Chiaki Terashima
- Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
- Research Center for Space System Innovation, Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Atsuo Yasumori
- Department of Materials Science and Technology, Faculty of Advanced Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Akira Fujishima
- Research Center for Space System Innovation, Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Antoni W. Morawski
- Department of Inorganic Chemical Technology and Environment Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Pułaskiego 10, 70-322 Szczecin, Poland
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Pecson B, Kaufmann A, Sharvelle S, Post B, Leverenz H, Ashbolt N, Olivieri A. Risk-based treatment targets for onsite non-potable water systems using new pathogen data. JOURNAL OF WATER AND HEALTH 2022; 20:1558-1575. [PMID: 36308499 DOI: 10.2166/wh.2022.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Using local sources (roof runoff, stormwater, graywater, and onsite wastewater) to meet non-potable water demands can minimize potable water use in buildings and increase supply reliability. In 2017, an Independent Advisory Panel developed a risk-based framework to identify pathogen log reduction targets (LRTs) for onsite non-potable water systems (ONWSs). Subsequently, California's legislature mandated the development and adoption of regulations-including risk-based LRTs-for use in multifamily residential, commercial, and mixed-use buildings. A California Expert Panel was convened in 2021 to (1) update the LRT requirements using new, quantitative pathogen data and (2) propose treatment trains capable of meeting the updated LRTs. This paper presents the updated risk-based LRTs for multiple pathogens (viruses, protozoa, and bacteria) and an expanded set of end-uses including toilet flushing, clothes washing, irrigation, dust and fire suppression, car washing, and decorative fountains. The updated 95th percentile LRTs required for each source water, pathogen, and end-use were typically within 1-log10 of the 2017 LRTs regardless of the approach used to estimate pathogen concentrations. LRT requirements decreased with influent pathogen concentrations from wastewater to graywater to stormwater to roof runoff. Cost and footprint estimates provide details on the capital, operations and maintenance, and siting requirements for ONWS implementation.
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Affiliation(s)
- Brian Pecson
- Trussell Technologies, 1939 Harrison Street, Oakland, California 94612, USA E-mail:
| | - Anya Kaufmann
- Trussell Technologies, 1939 Harrison Street, Oakland, California 94612, USA E-mail:
| | - Sybil Sharvelle
- Colorado State University, Scott Bioengineering Building 246, Fort Collins, Colorado 80523, USA
| | - Brie Post
- Trussell Technologies, 1939 Harrison Street, Oakland, California 94612, USA E-mail:
| | - Harold Leverenz
- Department of Civil and Environmental Engineering, University of California, Davis, California 95616, USA
| | - Nicholas Ashbolt
- Faculty of Science and Engineering, Southern Cross University, Military Road, East Lismore, New South Wales 2480, Australia
| | - Adam Olivieri
- EOA, Inc., 1410 Jackson Street, Oakland, California 94612, USA
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Viñas V, Sokolova E, Malm A, Bergstedt O, Pettersson TJR. Cross-connections in drinking water distribution networks: Quantitative microbial risk assessment in combination with fault tree analysis and hydraulic modelling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 831:154874. [PMID: 35358515 DOI: 10.1016/j.scitotenv.2022.154874] [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: 11/17/2021] [Revised: 02/25/2022] [Accepted: 03/24/2022] [Indexed: 06/14/2023]
Abstract
Deficiencies in drinking water distribution networks, such as cross-connections, may lead to contamination of the drinking water and pose a serious health risk to consumers. Cross-connections and backflows are considered among the most severe public health risks in distribution networks. The aim of this paper was to provide a framework for estimating the risk of infection from cross-connection and backflow events. Campylobacter, norovirus, and Cryptosporidium were chosen as reference pathogens for this study. The theoretical framework was constructed based on the fault tree analysis methodology. National aggregated cross-connection incident data was used to calculate the probability of a contamination event occurring in Swedish networks. Three risk cases were evaluated: endemic, elevated, and extreme. Quantitative microbial risk assessment (QMRA) was used to assess daily risk of infection for average national estimates. The framework was also evaluated using local data from the Gothenburg network. The daily risk of infection from cross-connection and backflow events in Swedish networks was generally above an acceptable target level of 10-6 for all reference pathogens and modelled cases; the exception was for the Gothenburg system where the risk was lower than 10-7. An outbreak case study was used to validate the framework results. For the outbreak case study, contaminant transport in the network was simulated using hydraulic modelling (EPANET), and risk estimates were calculated using QMRA. The outbreak simulation predicted between 97 and 148 symptomatic infections, while the epidemiological survey conducted during the outbreak reported 179 cases of illness. The fault tree analysis framework was successfully validated using an outbreak case study, though it was shown on the example of Gothenburg that local data is still needed for well-performing systems. The framework can help inform microbial risk assessments for drinking water suppliers, especially ones with limited resources and expertise in this area.
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Affiliation(s)
- Victor Viñas
- Department of Architecture and Civil Engineering, Water Environment Technology, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
| | - Ekaterina Sokolova
- Department of Architecture and Civil Engineering, Water Environment Technology, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden; Department of Earth Sciences, Uppsala University, Uppsala, Sweden
| | - Annika Malm
- Department of Architecture and Civil Engineering, Water Environment Technology, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden; Kungsbacka Municipality, Kungsbacka, Sweden
| | - Olof Bergstedt
- Department of Architecture and Civil Engineering, Water Environment Technology, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden; Sustainable Waste and Water, City of Gothenburg, Gothenburg, Sweden
| | - Thomas J R Pettersson
- Department of Architecture and Civil Engineering, Water Environment Technology, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
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11
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Ramlal PS, Lin J, Buckley CA, Stenström TA, Amoah ID. An assessment of the health risks associated with shared sanitation: a case study of the community ablution blocks in Durban, South Africa. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:166. [PMID: 35142880 PMCID: PMC9035208 DOI: 10.1007/s10661-022-09815-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 01/22/2022] [Indexed: 06/14/2023]
Abstract
Shared sanitation facilities have been hailed as an innovative approach to solve the challenge with sanitation access. However, these facilities may act as hotspots for disease transmission due to unhygienic conditions. In this study we used quantitative (based on Escherichia coli contamination) techniques to assess the health risks associated with the use of community ablution blocks (CABs). The most contaminated surfaces were the cistern handle (5.7 Log10 cfu/cm2) and internal pull latch (5.8 Log10 cfu/cm2). Based on the E. coli contamination, at least two people out of 100 CAB users might be potentially infected when they touch "hot" surfaces. These risks were modelled assuming transfer of potentially pathogenic E. coli from these surfaces to the mouth. The incorporation of risk-reduction measures, such as wiping of these surfaces or washing of hands, could potentially result in significant reduction of infection risks. The most significant risk-reduction intervention was determined to be wiping of the contact surfaces, especially twice prior to contact. A combination of risk-reduction interventions could further reduce the risks. This study shows that contamination of contact surfaces within shared CABs could lead to increased risks of infections, requiring measures aimed at reducing the associated risks. The risk assessment framework used in this study could therefore be applied in similar settings to estimate associated health risks with the use of such facilities.
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Affiliation(s)
- Preshod S Ramlal
- eThekwini Municipality Health Department, 9 Archie Gumede Place, 4001, Durban, South Africa.
- School of Life Sciences, University of KwaZulu-Natal, KwaZulu-Natal, 4001, Durban, South Africa.
| | - Johnson Lin
- School of Life Sciences, University of KwaZulu-Natal, KwaZulu-Natal, 4001, Durban, South Africa
| | - Christopher A Buckley
- WASH Research and Development Centre, University of KwaZulu-Natal, KwaZulu-Natal, 4001, Durban, South Africa
| | - Thor Axel Stenström
- Institute for Water and Wastewater Technology, Durban University of Technology, KwaZulu-Natal, Durban, South Africa
| | - Isaac D Amoah
- Institute for Water and Wastewater Technology, Durban University of Technology, KwaZulu-Natal, Durban, South Africa
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12
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Nyika J, Dinka M. A scientometric study on quantitative microbial risk assessment in water quality analysis across 6 years (2016-2021). JOURNAL OF WATER AND HEALTH 2022; 20:329-343. [PMID: 36366990 DOI: 10.2166/wh.2022.228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Water contamination by microbes is a growing environmental challenge that has exacerbated the apparent scarcity of safe drinking water. To alleviate this challenge, it is important to screen water for pathogens to reduce the risk of contracting waterborne diseases among consumers. The use of the quantitative microbial risk assessment (QMRA) tool to approximate illness possibility from exposure to microorganisms using dose-response models between pathogens and their associated health impacts is, therefore, recommended. The aim of this study was to explore the use of QMRA in water quality assessment using a scientometric approach and data sourced from the Web of Science (WoS) database for the period between 2016 and 2021. Articles were searched in the WoS databases before downloading the content for a bibliometric analysis using the VOSviewer software. Additionally, Microsoft Excel was used to analyze the inter-relationships of the searched results. Journal articles had the highest results from the searched query at 90.6% compared to other forms of output. High-impact journals such as the Science of the Total Environment and Water Research had the highest number of publications at 11.056 and 7.5%, respectively. Keyword analysis showed the multidisciplinary nature of the search query based on the clustered themes. The USA and China showed greater publication output with a total of 51.7% of total publications compared to developing countries due to their high research potential and extensive collaborative networks. A similar trend was evident in the institutional analysis with the University of California, USA, and the Chinese Academy of Sciences being the highest research contributors with 8% of the searched output. The study highlighted the need to extend research inputs to developing countries of Africa and Asia to improve their research and development capacity, productivity and share knowledge on QMRA in water quality assessment.
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Affiliation(s)
- Joan Nyika
- Department of Civil Engineering Science, University of Johannesburg, APK Campus 2006, Johannesburg, South Africa E-mail:
| | - Megersa Dinka
- Department of Civil Engineering Science, University of Johannesburg, APK Campus 2006, Johannesburg, South Africa E-mail:
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13
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Meng X, Wang X, Meng S, Wang Y, Liu H, Liang D, Fan W, Min H, Huang W, Chen A, Zhu H, Peng G, Liu J, Qiu Z, Wang T, Yang L, Wei Y, Huo P, Zhang D, Liu Y. A Global Overview of SARS-CoV-2 in Wastewater: Detection, Treatment, and Prevention. ACS ES&T WATER 2021; 1:2174-2185. [PMID: 37566346 PMCID: PMC8457323 DOI: 10.1021/acsestwater.1c00146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Indexed: 05/06/2023]
Abstract
A novel coronavirus (SARS-CoV-2) causing corona virus disease 2019 (COVID-19) has attracted global attention due to its highly infectious and pathogenic properties. Most of current studies focus on aerosols released from infected individuals, but the presence of SARS-CoV-2 in wastewater also should be examined. In this review, we used bibliometrics to statistically evaluate the importance of water-related issues in the context of COVID-19. The results show that the levels and transmission possibilities of SARS-CoV-2 in wastewater are the main concerns, followed by potential secondary pollution by the intensive use of disinfectants, sludge disposal, and the personal safety of workers. The presence of SARS-CoV-2 in wastewater requires more attention during the COVID-19 pandemic. Thus, the most effective techniques, i.e., wastewater-based epidemiology and quantitative microbial risk assessment, for virus surveillance in wastewater are systematically analyzed. We further explicitly review and analyze the successful operation of a sewage treatment plant in Huoshenshan Hospital in China as an example and reference for other sewage treatment systems to properly ensure discharge safety and tackle the COVID-19 pandemic. This review offers deeper insight into the prevention and control of SARS-CoV-2 and similar viruses in the post-COVID-19 era from a wastewater perspective.
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Affiliation(s)
- Xianghao Meng
- School of Space and Environment, Beihang
University, Beijing 100191, P. R. China
| | - Xuye Wang
- School of Space and Environment, Beihang
University, Beijing 100191, P. R. China
| | - Shujuan Meng
- School of Space and Environment, Beihang
University, Beijing 100191, P. R. China
| | - Ying Wang
- School of Space and Environment, Beihang
University, Beijing 100191, P. R. China
| | - Hongju Liu
- School of Space and Environment, Beihang
University, Beijing 100191, P. R. China
| | - Dawei Liang
- School of Space and Environment, Beihang
University, Beijing 100191, P. R. China
| | - Wenhong Fan
- School of Space and Environment, Beihang
University, Beijing 100191, P. R. China
| | - Hongping Min
- China Construction Third Bureau Green
Industry Investment Company, Ltd., Wuhan 430035, P. R.
China
| | - Wenhai Huang
- China Construction Third Bureau Green
Industry Investment Company, Ltd., Wuhan 430035, P. R.
China
| | - Anming Chen
- China Construction Third Bureau Green
Industry Investment Company, Ltd., Wuhan 430035, P. R.
China
| | - Haijun Zhu
- China Construction Third Bureau Green
Industry Investment Company, Ltd., Wuhan 430035, P. R.
China
| | - Guanping Peng
- China Construction Third Bureau Green
Industry Investment Company, Ltd., Wuhan 430035, P. R.
China
| | - Jun Liu
- China Construction Third Bureau Green
Industry Investment Company, Ltd., Wuhan 430035, P. R.
China
| | - Zhenhuan Qiu
- China Construction Third Bureau Green
Industry Investment Company, Ltd., Wuhan 430035, P. R.
China
| | - Tao Wang
- China Construction Third Bureau Green
Industry Investment Company, Ltd., Wuhan 430035, P. R.
China
| | - Linyan Yang
- School of Resources and Environmental Engineering,
East China University of Science and Technology, Shanghai
200237, P. R. China
| | - Yuan Wei
- State Key Laboratory of Environmental Criteria and
Risk Assessment, Chinese Research Academy of Environmental
Science, Beijing 100012, P. R. China
| | - Peishu Huo
- School of Environment, Tsinghua
University, Beijing 100084, P. R. China
| | - Dayi Zhang
- School of Environment, Tsinghua
University, Beijing 100084, P. R. China
| | - Yu Liu
- School of Civil and Environmental Engineering,
Nanyang Technological University, 50 Nanyang Avenue,
Singapore 639798
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14
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Noman E, Al-Gheethi A, Radin Mohamed RMS, Talip B, Al-Sahari M, Al-Shaibani M. Quantitative microbiological risk assessment of complex microbial community in Prawn farm wastewater and applicability of nanoparticles and probiotics for eliminating of antibiotic-resistant bacteria. JOURNAL OF HAZARDOUS MATERIALS 2021; 419:126418. [PMID: 34171673 DOI: 10.1016/j.jhazmat.2021.126418] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 06/02/2021] [Accepted: 06/14/2021] [Indexed: 06/13/2023]
Abstract
The current review highlighted the quantitative microbiological risk assessment of Vibrio parahaemolyticus in Prawn farm wastewaters (PFWWs) and the applicability of nanoparticles for eliminating antibiotic-resistant bacteria (ARB). The high availability of the antibiotics in the environment and their transmission into human through the food-chain might cause unknown health effects. The aquaculture environments are considered as a reservoir for the antibiotic resistance genes (ARGs) and contributed effectively in the increasing of ABR. The metagenomic analysis is used to explore ARGs in the non-clinical environment. V. parahaemolyticus is among the pathogenic bacteria which are transmitted through sea food causing human acute gastroenteritis due to available thermostable direct hemolysin (tdh), adhesins, TDH related hemolysin (trh). The inactivation of pathogenic bacteria using nanoparticles act by disturbing the cell membrane, interrupting the transport system, DNA and mitochondria damage, and oxidizing the cellular component by reactive oxygen species (ROS). The chloramphenicol, nitrofurans, and nitroimidazole are among the prohibited drugs in fish and fishery product. The utilization of probiotics is the most effective and safe alternative for antibiotics in Prawn aquaculture. This review will ensure public understanding among the readers on how they can decrease the risk of the antimicrobial resistance distribution in the environment.
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Affiliation(s)
- Efaq Noman
- Department of Applied Microbiology, Faculty of Applied Science, Taiz University, Yemen; Faculty of Applied Sciences and Technology, Universiti Tun Hussein Onn Malaysia (UTHM), Pagoh Higher Education Hub, KM 1, Jalan Panchor, 84000 Panchor, Johor, Malaysia
| | - Adel Al-Gheethi
- Micropollutant Research Centre (MPRC), Faculty of Civil Engineering & Built Environment, Universiti Tun Hussein Onn Malaysia, Parit Raja, 86400 Batu Pahat, Johor, Malaysia.
| | - Radin Maya Saphira Radin Mohamed
- Micropollutant Research Centre (MPRC), Faculty of Civil Engineering & Built Environment, Universiti Tun Hussein Onn Malaysia, Parit Raja, 86400 Batu Pahat, Johor, Malaysia
| | - Balkis Talip
- Faculty of Applied Sciences and Technology, Universiti Tun Hussein Onn Malaysia (UTHM), Pagoh Higher Education Hub, KM 1, Jalan Panchor, 84000 Panchor, Johor, Malaysia
| | - Mohamed Al-Sahari
- Micropollutant Research Centre (MPRC), Faculty of Civil Engineering & Built Environment, Universiti Tun Hussein Onn Malaysia, Parit Raja, 86400 Batu Pahat, Johor, Malaysia
| | - Muhanna Al-Shaibani
- Micropollutant Research Centre (MPRC), Faculty of Civil Engineering & Built Environment, Universiti Tun Hussein Onn Malaysia, Parit Raja, 86400 Batu Pahat, Johor, Malaysia
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15
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Shoults DC, Li Q, Petterson S, Rudko SP, Dlusskaya L, Leifels M, Scott C, Schlosser C, Ashbolt NJ. Pathogen performance testing of a natural swimming pool using a cocktail of microbiological surrogates and QMRA-derived management goals. JOURNAL OF WATER AND HEALTH 2021; 19:629-641. [PMID: 34371499 DOI: 10.2166/wh.2021.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In recent decades, natural swimming pools (NSPs) have gained popularity in Europe, especially in Germany and Austria. NSPs differ from swimming pools in that they utilize biological treatment processes based on wetland processes with no disinfection residual. However, data are missing on the specific log-reduction performance of NSPs to address enteric virus, bacteria, and parasitic protozoa removal considered necessary to meet the North American risk-based benchmark (<35 illnesses per 1,000 swimming events) set by the USEPA for voluntary swimming. In this study, we examined Canada's first NSP at Borden Park, Edmonton, Canada, to address the following three questions: (1) Given normal faecal shedding rates by bathers, what is the total log reduction (TLR) theoretically needed to meet the EPA benchmark? (2) what is the in-situ performance of the NSP based on spiking suitable microbial surrogates (MS2 coliphage, Enterococcus faecalis, and Saccharomyces cerevisiae [Baker's yeast])? and (3) how much time is required to reach acceptable bather risk levels under different representative volume-turnover rates? A reverse-quantitative microbial risk assessment (QMRA) revealed that of the four reference pathogens selected (Norovirus, Campylobacter, Cryptosporidium, and Giardia), only Norovirus was estimated to exceed the risk benchmark at the 50th, 75th, and 95th percentiles, while Campylobacter was the only other reference pathogen to exceed at the 95th percentile. Log-reduction values (LRVs) were similar to previous reports for bacterial indicators, and novel LRVs were estimated for the other two surrogates. A key finding was that more than 24 h treatment time would be necessary to provide acceptable bather protection following heavy bather use (378 bathers/day for main pool and 26 bathers/day for children's pool), due to the mixing dynamics of the treated water diluting out possible residual pool faecal contamination. The theoretical maximum number of people in the pool per day to be below USEPA's 35 gastro cases in 1,000 swimming events was 113, 47, and 8, at the 50th, 75th, and 95th percentiles. Further, the use of ultra-violet disinfection to the pool return flow had little effect on reducing the treatment time required.
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Affiliation(s)
- David C Shoults
- Centre for Water Resources Studies, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Qiaozhi Li
- School of Public Health, University of Alberta, Edmonton, Alberta T6G 2G7, Canada E-mail:
| | - Susan Petterson
- Water & Health Pty Ltd, North Sydney, NSW 2060, Australia; School of Medicine, Griffith University, Gold Coast, QLD 4222, Australia
| | - Sydney P Rudko
- School of Public Health, University of Alberta, Edmonton, Alberta T6G 2G7, Canada E-mail:
| | - Lena Dlusskaya
- School of Public Health, University of Alberta, Edmonton, Alberta T6G 2G7, Canada E-mail:
| | - Mats Leifels
- Singapore Centre of Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Canada
| | - Candis Scott
- School of Public Health, University of Alberta, Edmonton, Alberta T6G 2G7, Canada E-mail:
| | - Cyndi Schlosser
- Borden Park, City of Edmonton, Edmonton, Alberta T5B 4W8, Canada
| | - Nicholas J Ashbolt
- School of Public Health, University of Alberta, Edmonton, Alberta T6G 2G7, Canada E-mail: ; Faculty of Science and Engineering, Southern Cross University, East Lismore, NSW 2480, Australia
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16
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Sylvestre É, Prévost M, Burnet JB, Smeets P, Medema G, Hachad M, Dorner S. Using surrogate data to assess risks associated with microbial peak events in source water at drinking water treatment plants. WATER RESEARCH 2021; 200:117296. [PMID: 34098267 DOI: 10.1016/j.watres.2021.117296] [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: 02/19/2021] [Revised: 05/20/2021] [Accepted: 05/23/2021] [Indexed: 06/12/2023]
Abstract
A monitoring strategy was implemented at two drinking water treatment plants in Quebec, Canada, to evaluate microbial reduction performances of full-scale treatment processes under different source water conditions. β-D-glucuronidase activity in source water was automatically monitored in near-real-time to establish baseline and event conditions at each location. High-volume water samples (50-1,500 L) were collected at the inflow and the outflow of coagulation/flocculation, filtration, and UV disinfection processes and were analysed for two naturally occurring surrogate organisms: Escherichia coli and Clostridium perfringens. Source water Cryptosporidium data and full-scale C. perfringens reduction data were entered into a quantitative microbial risk assessment (QMRA) model to estimate daily infection risks associated with exposures to Cryptosporidium via consumption of treated drinking water. Daily mean E. coli and Cryptosporidium concentrations in source water under event conditions were in the top 5% (agricultural site) or in the top 15% (urban site) of what occurs through the year at these drinking water treatment plants. Reduction performances of up to 6.0-log for E. coli and 5.6-log for C. perfringens were measured by concentrating high-volume water samples throughout the treatment train. For both drinking water treatment plants, removal performances by coagulation/flocculation/sedimentation processes were at the high end of the range of those reported in the literature for bacteria and bacterial spores. Reductions of E. coli and C. perfringens by floc blanket clarification, ballasted clarification and rapid sand filtration did not deteriorate during two snowmelt/rainfall events. QMRA results suggested that daily infection risks were similar during two rainfall/snowmelt events than during baseline conditions. Additional studies investigating full-scale reductions would be desirable to improve the evaluation of differences in treatment performances under various source water conditions.
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Affiliation(s)
- Émile Sylvestre
- NSERC Industrial Chair on Drinking Water, Department of Civil, Geological, and Mining Engineering, Polytechnique Montreal, Montreal, Quebec, H3C 3A7, Canada; Canada Research Chair in Source Water Protection, Department of Civil, Geological, and Mining Engineering, Polytechnique Montreal, Montreal, Quebec, H3C 3A7, Canada.
| | - Michèle Prévost
- NSERC Industrial Chair on Drinking Water, Department of Civil, Geological, and Mining Engineering, Polytechnique Montreal, Montreal, Quebec, H3C 3A7, Canada
| | - Jean-Baptiste Burnet
- NSERC Industrial Chair on Drinking Water, Department of Civil, Geological, and Mining Engineering, Polytechnique Montreal, Montreal, Quebec, H3C 3A7, Canada; Canada Research Chair in Source Water Protection, Department of Civil, Geological, and Mining Engineering, Polytechnique Montreal, Montreal, Quebec, H3C 3A7, Canada
| | - Patrick Smeets
- KWR Water Research Institute, Groningenhaven 7, 3433 PE Nieuwegein, The Netherlands
| | - Gertjan Medema
- KWR Water Research Institute, Groningenhaven 7, 3433 PE Nieuwegein, The Netherlands; Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600GA, Delft, The Netherlands
| | - Mounia Hachad
- NSERC Industrial Chair on Drinking Water, Department of Civil, Geological, and Mining Engineering, Polytechnique Montreal, Montreal, Quebec, H3C 3A7, Canada; Canada Research Chair in Source Water Protection, Department of Civil, Geological, and Mining Engineering, Polytechnique Montreal, Montreal, Quebec, H3C 3A7, Canada
| | - Sarah Dorner
- Canada Research Chair in Source Water Protection, Department of Civil, Geological, and Mining Engineering, Polytechnique Montreal, Montreal, Quebec, H3C 3A7, Canada
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17
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Detection of SARS-CoV-2 RNA on contact surfaces within shared sanitation facilities. Int J Hyg Environ Health 2021; 236:113807. [PMID: 34265632 PMCID: PMC8270751 DOI: 10.1016/j.ijheh.2021.113807] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 01/22/2023]
Abstract
Contamination of contact surfaces with SARS-CoV-2 has been reported as a potential route for the transmission of COVID-19. This could be a major issue in developing countries where access to basic sanitation is poor, leading to the sharing of toilet facilities. In this study, we report SARS-CoV-2 contamination of key contact surfaces in shared toilets and the probabilistic risks of COVID-19 infections based on detection and quantification of the nucleic acid on the surfaces. We observed that 54-69% of the contact surfaces were contaminated, with SARS-CoV-2 loads ranging from 28.1 to 132.7 gene copies per cm2. Toilet seats had the highest contamination, which could be attributed to shedding of the virus in feces and urine. We observed a significant reduction in viral loads on the contaminated surfaces after cleaning, showing the potential of effective cleaning on the reduction of contamination. The pattern of contamination indicates that the most contaminated surfaces are those that are either commonly touched by users of the shared toilets or easily contaminated with feces and urine. These surfaces were the toilet seats, cistern handles and tap handles. The likelihood (probability) of infection with COVID-19 on these surfaces was highest on the toilet seat (1.76 × 10-4(1.58 × 10-6)) for one time use of the toilet. These findings highlight the potential risks for COVID-19 infections in the event that intact infectious viral particles are deposited on these contact surfaces. Therefore, this study shows that shared toilet facilities in densely populated areas could lead to an increase in risks of COVID-19 infections. This calls for the implementation of risk reduction measures, such as regular washing of hands with soap, strict adherence to wearing face masks, and effective and regular cleaning of shared facilities.
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Byrne DM, Hamilton KA, Houser SA, Mubasira M, Katende D, Lohman HAC, Trimmer JT, Banadda N, Zerai A, Guest JS. Navigating Data Uncertainty and Modeling Assumptions in Quantitative Microbial Risk Assessment in an Informal Settlement in Kampala, Uganda. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:5463-5474. [PMID: 33750111 DOI: 10.1021/acs.est.0c05693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Decision-makers in developing communities often lack credible data to inform decisions related to water, sanitation, and hygiene. Quantitative microbial risk assessment (QMRA), which quantifies pathogen-related health risks across exposure routes, can be informative; however, the utility of QMRA for decision-making is often undermined by data gaps. This work integrates QMRA, uncertainty and sensitivity analyses, and household surveys in Bwaise, Kampala (Uganda) to characterize the implications of censored data management, identify sources of uncertainty, and incorporate risk perceptions to improve the suitability of QMRA for informal settlements or similar settings. In Bwaise, drinking water, hand rinse, and soil samples were collected from 45 households and supplemented with data from 844 surveys. Quantified pathogen (adenovirus, Campylobacter jejuni, and Shigella spp./EIEC) concentrations were used with QMRA to model infection risks from exposure through drinking water, hand-to-mouth contact, and soil ingestion. Health risks were most sensitive to pathogen data, hand-to-mouth contact frequency, and dose-response models (particularly C. jejuni). When managing censored data, results from upper limits of detection, half of limits of detection, and uniform distributions returned similar results, which deviated from lower limits of detection and maximum likelihood estimation imputation approaches. Finally, risk perceptions (e.g., it is unsafe to drink directly from a water source) were identified to inform risk management.
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Affiliation(s)
- Diana M Byrne
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, 3221 Newmark Civil Engineering Laboratory, Urbana, Illinois 61801, United States
| | - Kerry A Hamilton
- The School with Sustainable Engineering and the Built Environment and The Biodesign Institute Center for Environmental Health Engineering, Arizona State University, Tempe, Arizona 85287, United States
| | - Stephanie A Houser
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, 3221 Newmark Civil Engineering Laboratory, Urbana, Illinois 61801, United States
| | - Muwonge Mubasira
- Community Integrated Development Initiatives, P.O. Box 764, Kampala, Uganda
| | - David Katende
- Community Integrated Development Initiatives, P.O. Box 764, Kampala, Uganda
| | - Hannah A C Lohman
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, 3221 Newmark Civil Engineering Laboratory, Urbana, Illinois 61801, United States
| | - John T Trimmer
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, 3221 Newmark Civil Engineering Laboratory, Urbana, Illinois 61801, United States
| | - Noble Banadda
- Department of Agricultural & Biosystems Engineering, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - Assata Zerai
- Department of Sociology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Jeremy S Guest
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, 3221 Newmark Civil Engineering Laboratory, Urbana, Illinois 61801, United States
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19
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Hajare R, Labhasetwar P, Nagarnaik P. Evaluation of pathogen risks using QMRA to explore wastewater reuse options: A case study from New Delhi in India. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2021; 83:543-555. [PMID: 33600360 DOI: 10.2166/wst.2020.583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Selecting appropriate reuse for treated wastewater is a challenge. The current investigation outlines the utilization of quantitative microbial risk assessment (QMRA) to assist Effluent Treatment Plant (ETP) management to determine the best-possible reuse of treated wastewater from 11 ETPs in Delhi. Four representative pathogens: pathogenic Escherichia coli spp., Salmonella spp., Cryptosporidium spp. and Giardia spp. were selected to characterize microbial water quality. Reuse options selected based on the survey and interaction with ETP managers include crop irrigation, garden irrigation, toilet flush and industrial applications. The probability of infection was characterized for two exposure groups: workers and children. Water quality monitoring indicates the occurrence of pathogenic E. coli spp. (100%), Salmonella spp. (63%), Cryptosporidium spp. (81%) and Giardia spp. (45%) in the treated wastewater. QMRA reveals the annual median-probability of infection above acceptable limits for pathogenic E. coli spp., Cryptosporidium spp. and Salmonella spp. The probabilities of Giardia-associated infections were low. Adults showed a 1.24 times higher probability of infection compared to children. Sensitivity analysis indicated pathogen concentration as the most critical factor. The study highlights that the existing plans for chlorination-based treatment technology may prove insufficient in reducing the risk for selected reuse options; but, alternate on-site control measures and up-grading water reuse protocol may be effective.
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Affiliation(s)
- Rajashree Hajare
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, Uttar Pradesh, India
| | - Pawan Labhasetwar
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, Uttar Pradesh, India; CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nagpur 440 020, Maharashtra, India E-mail:
| | - Pranav Nagarnaik
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, Uttar Pradesh, India; CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nagpur 440 020, Maharashtra, India E-mail:
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Zaneti RN, Girardi V, Spilki FR, Mena K, Westphalen APC, da Costa Colares ER, Pozzebon AG, Etchepare RG. Quantitative microbial risk assessment of SARS-CoV-2 for workers in wastewater treatment plants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 754:142163. [PMID: 32911141 PMCID: PMC7468340 DOI: 10.1016/j.scitotenv.2020.142163] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/01/2020] [Accepted: 09/01/2020] [Indexed: 04/14/2023]
Abstract
Faecal-oral transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is yet to be validated, but it is a critical issue and additional research is needed to elucidate the risks of the novel coronavirus in sanitation systems. This is the first study that investigates the potential health risks of SARS-CoV-2 in sewage to wastewater treatment plant (WWTP) workers. A quantitative microbial risk assessment (QMRA) is applied for three COVID-19 scenarios (moderate, aggressive and extreme) to study the effects of different stages of the pandemic in terms of percentage of infected population on the probability of infection to WWTP workers. A dose-response model for SARS-CoV-1 (as a surrogate pathogen) is assumed in the QMRA for SARS-CoV-2 using an exponential model with k = 4.1 × 102. Literature data are incorporated to inform assumptions for calculating the viral load, develop the model, and derive a tolerable infection risk. Results reveal that estimates of viral RNA in sewage at the entrance of WWTPs ranged from 4.14 × 101 to 5.23 × 103 GC·mL-1 (viable virus concentration from 0.04 to 5.23 PFU·mL-1, respectively). In addition, estimated risks for the aggressive and extreme scenarios (2.6 × 10-3 and 1.3 × 10-2, respectively) were likely to be above the derived tolerable infection risk for SARS-CoV-2 of 5.5 × 10-4 pppy, thus reinforcing the concern of sewage systems as a possible transmission pathway of SARS-CoV-2. These findings are helpful as an early health warning tool and in prioritizing upcoming risk management strategies, such as Emergency Response Plans (ERPs) for water and sanitation operators during the COVID-19 and future pandemics.
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Affiliation(s)
| | | | | | - Kristina Mena
- University of Texas - Houston School of Public Health, Houston, United States
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21
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Zaneti RN, Girardi V, Spilki FR, Mena K, Westphalen APC, da Costa Colares ER, Pozzebon AG, Etchepare RG. Quantitative microbial risk assessment of SARS-CoV-2 for workers in wastewater treatment plants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 754:142163. [PMID: 32911141 DOI: 10.1101/2020.05.28.20116277] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/01/2020] [Accepted: 09/01/2020] [Indexed: 05/18/2023]
Abstract
Faecal-oral transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is yet to be validated, but it is a critical issue and additional research is needed to elucidate the risks of the novel coronavirus in sanitation systems. This is the first study that investigates the potential health risks of SARS-CoV-2 in sewage to wastewater treatment plant (WWTP) workers. A quantitative microbial risk assessment (QMRA) is applied for three COVID-19 scenarios (moderate, aggressive and extreme) to study the effects of different stages of the pandemic in terms of percentage of infected population on the probability of infection to WWTP workers. A dose-response model for SARS-CoV-1 (as a surrogate pathogen) is assumed in the QMRA for SARS-CoV-2 using an exponential model with k = 4.1 × 102. Literature data are incorporated to inform assumptions for calculating the viral load, develop the model, and derive a tolerable infection risk. Results reveal that estimates of viral RNA in sewage at the entrance of WWTPs ranged from 4.14 × 101 to 5.23 × 103 GC·mL-1 (viable virus concentration from 0.04 to 5.23 PFU·mL-1, respectively). In addition, estimated risks for the aggressive and extreme scenarios (2.6 × 10-3 and 1.3 × 10-2, respectively) were likely to be above the derived tolerable infection risk for SARS-CoV-2 of 5.5 × 10-4 pppy, thus reinforcing the concern of sewage systems as a possible transmission pathway of SARS-CoV-2. These findings are helpful as an early health warning tool and in prioritizing upcoming risk management strategies, such as Emergency Response Plans (ERPs) for water and sanitation operators during the COVID-19 and future pandemics.
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Affiliation(s)
| | | | | | - Kristina Mena
- University of Texas - Houston School of Public Health, Houston, United States
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22
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The role of biofilm in the development and dissemination of ubiquitous pathogens in drinking water distribution systems: an overview of surveillance, outbreaks, and prevention. World J Microbiol Biotechnol 2021; 37:36. [PMID: 33507414 DOI: 10.1007/s11274-021-03008-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 01/19/2021] [Indexed: 12/30/2022]
Abstract
A variety of pathogenic microorganisms can survive in the drinking water distribution systems (DWDS) by forming stable biofilms and, thus, continually disseminating their population through the system's dynamic water bodies. The ingestion of the pathogen-contaminated water could trigger a broad spectrum of illnesses and well-being-related obstacles. These waterborne diseases are a significant concern for babies, pregnant women, and significantly low-immune individuals. This review highlights the recent advances in understanding the microbiological aspects of drinking water quality, biofilm formation and its dynamics, health issues caused by the emerging microbes in biofilm, and approaches for biofilm investigation its prevention and suppression in DWDS.
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Quantitation of Risk Reduction of E. coli Transmission After Using Antimicrobial Hand Soap. Pathogens 2020; 9:pathogens9100778. [PMID: 32977715 PMCID: PMC7598586 DOI: 10.3390/pathogens9100778] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 08/28/2020] [Accepted: 09/01/2020] [Indexed: 11/25/2022] Open
Abstract
Handwashing with soap is an effective and economical means to reduce the likelihood of Escherichia coli infection from indirect contact with contaminated surfaces during food preparation. The purpose of this study was to conduct a quantitative microbial risk assessment (QMRA) to evaluate the risk of infection from indirect contact with fomites contaminated with E. coli after hand washing with antimicrobial hand soaps. A Monte Carlo simulation was done with a total of 10,000 simulations to compare the effectiveness of two antimicrobial and one control (non-antimicrobial) bar soaps in reducing the exposure and infection risk compared to no hand washing. The numbers of E. coli on several fomites commonly found in household kitchens, as well as the transfer rates between fomites and onto fingertips, were collected from the literature and experimental data. The sponsor company provided the E. coli survival on hands after washing with antimicrobial and control soaps. A number of scenarios were evaluated at two different exposure doses (high and low). Exposure scenarios included transfer of E. coli between meat-to-cutting board surface-to-hands, meat-to-knife surface-to-hands, and from a countertop surface-to-hands, kitchen sponge-to-hands, hand towel-to-hands, and dishcloth-to-hands. Results showed that the risks of illness after washing with the control soap was reduced approximately 5-fold compared to no handwashing. Washing with antimicrobial soap reduced the risk of E. coli infection by an average of about 40-fold compared with no handwashing. The antimicrobial soaps ranged from 3 to 32 times more effective than the non-antimicrobial soap, depending on the specific exposure scenario. Importance: The Centers for Disease Control and Prevention indicate the yearly incidence rate of Shiga Toxin producing E. coli infections is about 1.7/100,000, with about 10% of cases leading to life-threatening hemolytic uremic syndrome and 3–5% leading to death. Our findings confirm handwashing with soap reduces the risks associated with indirect transmission of E. coli infection from contact with fomites during food preparation. Further, in these exposure scenarios, antimicrobial soaps were more effective overall than the non-antimicrobial soap in reducing exposure to E. coli and risk of infection.
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Berglund EZ, Pesantez JE, Rasekh A, Shafiee ME, Sela L, Haxton T. Review of Modeling Methodologies for Managing Water Distribution Security. JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT 2020; 146:1-23. [PMID: 33627936 PMCID: PMC7898161 DOI: 10.1061/(asce)wr.1943-5452.0001265] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Water distribution systems are vulnerable to hazards that threaten water delivery, water quality, and physical and cybernetic infrastructure. Water utilities and managers are responsible for assessing and preparing for these hazards, and researchers have developed a range of computational frameworks to explore and identify strategies for what-if scenarios. This manuscript conducts a review of the literature to report on the state of the art in modeling methodologies that have been developed to support the security of water distribution systems. First, the major activities outlined in the emergency management framework are reviewed; the activities include risk assessment, mitigation, emergency preparedness, response, and recovery. Simulation approaches and prototype software tools are reviewed that have been developed by government agencies and researchers for assessing and mitigating four threat modes, including contamination events, physical destruction, interconnected infrastructure cascading failures, and cybernetic attacks. Modeling tools are mapped to emergency management activities, and an analysis of the research is conducted to group studies based on methodologies that are used and developed to support emergency management activities. Recommendations are made for research needs that will contribute to the enhancement of the security of water distribution systems.
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Affiliation(s)
- Emily Zechman Berglund
- Dept. of Civil, Construction, and Environmental Engineering, North Carolina State Univ., C.B. 7908, Raleigh, NC 27695
| | - Jorge E Pesantez
- Dept. of Civil, Construction, and Environmental Engineering, North Carolina State Univ., C.B. 7908, Raleigh, NC 27695
| | - Amin Rasekh
- Xylem Inc., 8601 Six Forks Rd., Raleigh, NC 27615
| | | | - Lina Sela
- Dept. of Civil, Architectural, and Environmental Engineering, Univ. of Texas at Austin, 301 E Dean Keeton St. Stop C1786, Austin, TX 78712
| | - Terranna Haxton
- Office of Research and Development, US Environmental Protection Agency, 26 W. Martin Luther King Dr., Cincinnati, OH 45268
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Owens CEL, Angles ML, Cox PT, Byleveld PM, Osborne NJ, Rahman MB. Implementation of quantitative microbial risk assessment (QMRA) for public drinking water supplies: Systematic review. WATER RESEARCH 2020; 174:115614. [PMID: 32087414 DOI: 10.1016/j.watres.2020.115614] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 02/02/2020] [Accepted: 02/10/2020] [Indexed: 05/04/2023]
Abstract
In the more than 15 years since its introduction, quantitative microbial risk assessment (QMRA) has become a widely used technique for assessing population health risk posed by waterborne pathogens. However, the variation in approaches taken for QMRA in relation to drinking water supply is not well understood. This systematic review identifies, categorises, and critically synthesises peer-reviewed and academic case studies of QMRA implementation for existing distributed public drinking water supplies. Thirty-nine English-language, peer-reviewed and academic studies published from 2003 to 2019 were identified. Key findings were synthesised in narrative form. The overall designs of the included studies varied widely, as did the assumptions used in risk calculation, especially in relation to pathogen dose. There was also substantial variation in the degree to which the use of location-specific data weighed with the use of assumptions when performing risk calculation. In general, the included studies' complexity did not appear to be associated with greater result certainty. Factors relating to pathogen dose were commonly influential on risk estimates whereas dose-response parameters tended to be of low relative influence. In two of the included studies, use of the 'susceptible fraction' factor was inconsistent with recognised guidance and potentially led to the underestimation of risk. While approaches and assumptions used in QMRA need not be standardised, improvement in the reporting of QMRA results and uncertainties would be beneficial. It is recommended that future authors consider the water supply QMRA reporting checklist developed for the current review. Consideration of the broad types of uncertainty relevant to QMRA is also recommended. Policy-makers should consider emergent discussion on acute microbial health-based targets when setting normative guidelines. The continued representation of QMRA case studies within peer-reviewed and academic literature would also enhance future implementation. Further research is needed on the optimisation of QMRA resourcing given the application context.
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Affiliation(s)
- Christopher E L Owens
- School of Public Health and Community Medicine, Faculty of Medicine, University of New South Wales, Kensington NSW 2052, Australia; Sydney Water Corporation, Parramatta NSW 2124, Australia.
| | - Mark L Angles
- Water Angles Consulting, Vaucluse NSW 2030, Australia
| | - Peter T Cox
- Sydney Water Corporation, Parramatta NSW 2124, Australia
| | | | - Nicholas J Osborne
- School of Public Health and Community Medicine, Faculty of Medicine, University of New South Wales, Kensington NSW 2052, Australia; School of Public Health, Faculty of Medicine, University of Queensland, Herston QLD 4006, Australia; European Centre for Environment and Human Health, University of Exeter, Royal Cornwall Hospital, Truro TR1 3HD, United Kingdom
| | - Md Bayzid Rahman
- School of Public Health and Community Medicine, Faculty of Medicine, University of New South Wales, Kensington NSW 2052, Australia
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Zhang Q, Gallard J, Wu B, Harwood VJ, Sadowsky MJ, Hamilton KA, Ahmed W. Synergy between quantitative microbial source tracking (qMST) and quantitative microbial risk assessment (QMRA): A review and prospectus. ENVIRONMENT INTERNATIONAL 2019; 130:104703. [PMID: 31295713 DOI: 10.1016/j.envint.2019.03.051] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 03/21/2019] [Accepted: 03/21/2019] [Indexed: 05/20/2023]
Abstract
The use of microbial source tracking (MST) marker genes has grown in recent years due to the need to attribute point and non-point fecal contamination to specific sources. Quantitative microbial risk assessment (QMRA) is a modeling approach used to estimate health risks from exposure to feces-contaminated water and associated pathogens. A combination of these approaches [quantitative MST (qMST) and QMRA] can provide additional pathogen-related information for prioritizing and addressing health risks, compared to reliance on conventional fecal indicator bacteria (FIB). To inform expansion of this approach, a review of published qMST-QMRA studies was conducted to summarize the state of the science and to identify research needs. The reviewed studies primarily aimed to identify what levels of MST marker genes in hypothetical recreational waterbodies would exceed the United States Environmental Protection Agency (USEPA) risk benchmarks for primary contact recreators. The QMRA models calculated relationships between MST marker gene(s) and reference pathogens based on published data in the literature. The development of a robust, accurate relationship was identified as an urgent research gap for qMST-QMRA. This metric requires additional knowledge to quantify the relationship between MST marker genes and the degree of variability in decay of pathogens as a dynamic function of environmental conditions and combinations of fecal sources at multiple spatial and temporal scales. Improved characterization of host shedding rates of host-associated microorganisms (i.e., MST marker genes), as well as fate and transport of these microorganisms and their nucleic acids, would facilitate expansion of this approach to other exposure pathways. Incorporation of information regarding the recovery efficiency, and host-specificity of MST marker genes into QMRA model parameters, and the sensitivity analysis, would greatly improve risk management and site-specific water monitoring criteria.
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Affiliation(s)
- Qian Zhang
- BioTechnology Institute, University of Minnesota, 1479 Gortner Ave, St. Paul, MN 55108, USA
| | - Javier Gallard
- Department of Integrative Biology, SCA 110, University of South Florida, 4202 East Fowler Ave, Tampa, FL 33620, USA
| | - Baolei Wu
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No. 13 Yanta Road, Xi'an, Shaanxi 710055, PR China
| | - Valerie J Harwood
- Department of Integrative Biology, SCA 110, University of South Florida, 4202 East Fowler Ave, Tampa, FL 33620, USA
| | - Michael J Sadowsky
- BioTechnology Institute, University of Minnesota, 1479 Gortner Ave, St. Paul, MN 55108, USA; Department of Soil, Water & Climate and Department of Plant & Microbial Biology, University of Minnesota, 1991 Upper Buford Ave, St. Paul, MN 55108, USA
| | - Kerry A Hamilton
- School for Sustainable Engineering and the Built Environment, Arizona State University, 660 S College Ave, Tempe, AZ 85281, USA; The Biodesign Institute Center for Environmental Health Engineering, Arizona State University, 1001 S McAllister Ave, Tempe, AZ 85281, USA
| | - Warish Ahmed
- CSIRO Land and Water, Ecosciences Precinct, 41 Boggo Road, QLD 4102, Australia.
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Capsid Integrity qPCR—An Azo-Dye Based and Culture-Independent Approach to Estimate Adenovirus Infectivity after Disinfection and in the Aquatic Environment. WATER 2019. [DOI: 10.3390/w11061196] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Recreational, reclaimed and drinking source waters worldwide are under increasing anthropogenic pressure, and often contain waterborne enteric bacterial, protozoan, and viral pathogens originating from non-point source fecal contamination. Recently, the capsid integrity (ci)-qPCR, utilizing the azo-dyes propidium monoazide (PMA) or ethidium monoazide (EMA), has been shown to reduce false-positive signals under laboratory conditions as well as in food safety applications, thus improving the qPCR estimation of virions of public health significance. The compatibility of two widely used human adenovirus (HAdV) qPCR protocols was evaluated with the addition of a PMA/EMA pretreatment using a range of spiked and environmental samples. Stock suspensions of HAdV were inactivated using heat, UV, and chlorine before being quantified by cell culture, qPCR, and ci-qPCR. Apparent inactivation of virions was detected for heat and chlorine treated HAdV while there was no significant difference between ci-qPCR and qPCR protocols after disinfection by UV. In a follow-up comparative analysis under more complex matrix conditions, 51 surface and 24 wastewater samples pre/post UV treatment were assessed for enteric waterborne HAdV to evaluate the ability of ci-qPCR to reduce the number of false-positive results when compared to conventional qPCR and cell culture. Azo-dye pretreatment of non-UV inactivated samples was shown to improve the ability of molecular HAdV quantification by reducing signals from virions with an accessible genome, thereby increasing the relevance of qPCR results for public health purposes, particularly suited to resource-limited low and middle-income settings.
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Wood M, Simmonds L, MacAdam J, Hassard F, Jarvis P, Chalmers RM. Role of filtration in managing the risk from Cryptosporidium in commercial swimming pools - a review. JOURNAL OF WATER AND HEALTH 2019; 17:357-370. [PMID: 31095512 DOI: 10.2166/wh.2019.270] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Most commercial swimming pools use pressurised filters, typically containing sand media, to remove suspended solids as part of the water treatment process designed to keep water attractive, clean and safe. The accidental release of faecal material by bathers presents a poorly quantified risk to the safety of swimmers using the pool. The water treatment process usually includes a combination of maintaining a residual concentration of an appropriate biocide in the pool together with filtration to physically remove particles, including microbial pathogens, from the water. However, there is uncertainty about the effectiveness of treatment processes in removing all pathogens, and there has been growing concern about the number of reported outbreaks of the gastrointestinal disease cryptosporidiosis, caused by the chlorine-resistant protozoan parasite Cryptosporidium. A number of interacting issues influence the effectiveness of filtration for the removal of Cryptosporidium oocysts from swimming pools. This review explains the mechanisms by which filters remove particles of different sizes (including oocyst-sized particles, typically 4-6 μm), factors that affect the efficiency of particle removal (such as filtration velocity), current recommended management practices, and identifies further work to support the development of a risk-based management approach for the management of waterborne disease outbreaks from swimming pools.
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Affiliation(s)
- Martin Wood
- Pool Sentry Ltd, Dale Cottage, Stanton Dale, Ashbourne DE6 2BX, UK E-mail:
| | - Lester Simmonds
- Pool Sentry Ltd, Dale Cottage, Stanton Dale, Ashbourne DE6 2BX, UK E-mail:
| | - Jitka MacAdam
- Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK
| | | | - Peter Jarvis
- Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK
| | - Rachel M Chalmers
- Cryptosporidium Reference Unit, Public Health Wales, Microbiology and Health Protection, Singleton Hospital, Swansea, SA2 8QA, UK; This article has been made Open Access thanks to the generous support of a global network of libraries as part of the Knowledge Unlatched Select initiative
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Nilsen V, Christensen E, Myrmel M, Heistad A. Spatio-temporal dynamics of virus and bacteria removal in dual-media contact-filtration for drinking water. WATER RESEARCH 2019; 156:9-22. [PMID: 30897546 DOI: 10.1016/j.watres.2019.02.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 02/08/2019] [Accepted: 02/13/2019] [Indexed: 05/24/2023]
Abstract
Microorganism removal efficiencies in deep bed filters vary with time and depth in the filter bed as the filter collects particles. Improved knowledge of such dynamics is relevant for the design, operation and microbial risk assessment of filtration processes for drinking water treatment. Here we report on a high-resolution spatio-temporal characterization of virus and bacteria removal in a pilot-scale dual-media filter, operated in contact-filtration mode. Microorganisms investigated were bacteriophage Salmonella typhimurium 28B (plaque assay, n=154)), fRNA phage MS2 (plaque assay/RT-qPCR, n=87) and E. coli (Colilert-18, n=73). Microscopic and macroscopic filtration models were used to investigate and characterize the removal dynamics. Results show that ripening/breakthrough fronts for turbidity, viruses and E. coli migrated in a wave-like manner across the depth of the filter. Virus removal improved continuously throughout the filter cycle and viruses broke through almost simultaneously with turbidity. Ripening for E. coli took longer than ripening for turbidity, but the bacteria broke through before turbidity breakthrough. Instantaneous log-removal peaked at 3.2, 3.0 and 4.5 for 28B, MS2 and E. coli, respectively. However, true average log-removal during the period of stable effluent turbidity was significantly lower at 2.5, 2.3 and 3.6, respectively. Peak observed filter coefficients λ were higher than predicted by ideal filtration theory. This study demonstrates the importance of carefully designed sampling regimes when characterizing microorganism removal efficiencies of deep bed filters.
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Affiliation(s)
- Vegard Nilsen
- Norwegian University of Life Sciences, Faculty of Science and Technology, P.O.Box 5003, N-1432, Ås, Norway.
| | - Ekaterina Christensen
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, P.O.Box 8146 Dep, N-0033, Oslo, Norway
| | - Mette Myrmel
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, P.O.Box 8146 Dep, N-0033, Oslo, Norway
| | - Arve Heistad
- Norwegian University of Life Sciences, Faculty of Science and Technology, P.O.Box 5003, N-1432, Ås, Norway
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Bivins A, Beetsch N, Majuru B, Montgomery M, Sumner T, Brown J. Selecting Household Water Treatment Options on the Basis of World Health Organization Performance Testing Protocols. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:5043-5051. [PMID: 30998325 DOI: 10.1021/acs.est.8b05682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The World Health Organization's International Scheme to Evaluate Household Water Treatment Technologies serves to benchmark microbiological performance of existing and novel technologies and processes for small-scale drinking water treatment according to a tiered system. There is widespread uncertainty around which tiers of performance are most appropriate for technology selection and recommendation in humanitarian response or for routine safe water programming. We used quantitative microbial risk assessment (QMRA) to evaluate attributable reductions in diarrheal disease burden associated with water treatment technologies meeting the three tiers of performance under this Scheme, across a range of conditions. According to mean estimates and under most modeling conditions, potential health gains attributable to microbiologically improved drinking water are realized at the middle tier of performance: "comprehensive protection: high pathogen removal (★★)" for each reference pathogen. The highest tier of performance may yield additional marginal health gains where untreated water is especially contaminated and where adherence is 100%. Our results highlight that health gains from improved efficacy of household water treatment technology remain marginal when adherence is less than 90%. While selection of water treatment technologies that meet minimum WHO efficacy recommendations for comprehensive protection against waterborne pathogens is critical, additional criteria for technology choice and recommendation should focus on potential for correct, consistent, and sustained use.
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Affiliation(s)
- Aaron Bivins
- School of Civil and Environmental Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - Nikki Beetsch
- World Health Organization , Geneva 1211 , Switzerland
- NSF-International , Ann Arbor , Michigan 48105 , United States
| | | | | | - Trent Sumner
- School of Civil and Environmental Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - Joe Brown
- School of Civil and Environmental Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
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31
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Setty K, Loret JF, Courtois S, Hammer CC, Hartemann P, Lafforgue M, Litrico X, Manasfi T, Medema G, Shaheen M, Tesson V, Bartram J. Faster and safer: Research priorities in water and health. Int J Hyg Environ Health 2019; 222:593-606. [PMID: 30910612 PMCID: PMC6545151 DOI: 10.1016/j.ijheh.2019.03.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 03/08/2019] [Accepted: 03/11/2019] [Indexed: 11/22/2022]
Abstract
The United Nations' Sustainable Development Goals initiated in 2016 reiterated the need for safe water and healthy lives across the globe. The tenth anniversary meeting of the International Water and Health Seminar in 2018 brought together experts, students, and practitioners, setting the stage for development of an inclusive and evidence-based research agenda on water and health. Data collection relied on a nominal group technique gathering perceived research priorities as well as underlying drivers and adaptation needs. Under a common driver of public health protection, primary research priorities included the socioeconomy of water, risk assessment and management, and improved monitoring methods and intelligence. Adaptations stemming from these drivers included translating existing knowledge to providing safe and timely services to support the diversity of human water needs. Our findings present a comprehensive agenda of topics at the forefront of water and health research. This information can frame and inform collective efforts of water and health researchers over the coming decades, contributing to improved water services, public health, and socioeconomic outcomes.
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Affiliation(s)
- Karen Setty
- The Water Institute at University of North Carolina at Chapel Hill, Department of Environmental Sciences and Engineering, 166 Rosenau Hall, CB #7431, Chapel Hill, NC, 27599-7431, USA.
| | - Jean-Francois Loret
- Suez, Centre International de Recherche sur l'Eau et l'Environnement (CIRSEE), 38 rue du President Wilson, 78230, Le Pecq, France.
| | - Sophie Courtois
- Suez, Centre International de Recherche sur l'Eau et l'Environnement (CIRSEE), 38 rue du President Wilson, 78230, Le Pecq, France.
| | - Charlotte Christiane Hammer
- Norwich Medical School, University of East Anglia Faculty of Medicine and Health Sciences, Norwich, NR4 7TJ, UK.
| | - Philippe Hartemann
- Université de Lorraine, Faculté de Médecine, EA 7298, ERAMBO, DESP, Vandœuvre-lès-Nancy, France.
| | - Michel Lafforgue
- Suez Consulting, Le Bruyère 2000 - Bâtiment 1, Zone du Millénaire, 650 Rue Henri Becquerel, CS79542, 34961, Montpellier Cedex 2, France.
| | - Xavier Litrico
- Suez, Tour CB21, 16 Place de l'Iris, 92040, Paris La Defense Cedex, France.
| | - Tarek Manasfi
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland.
| | - Gertjan Medema
- KWR Watercycle Research Institute, Groningenhaven 7, 3433, PE, Nieuwegein, the Netherlands; Delft University of Technology, Stevinweg 1, 2628 CN, Delft, the Netherlands.
| | - Mohamed Shaheen
- School of Public Health, University of Alberta, 3-300 Edmonton Clinic Health Academy, 11405 - 87 Ave, Edmonton, AB T6G 1C9, Canada.
| | - Vincent Tesson
- French National Institute for Agricultural Research (INRA), UMR 1114 EMMAH, 228 route de l'Aérodrome, CS 40 509, 84914, Avignon Cedex 9, France.
| | - Jamie Bartram
- The Water Institute at University of North Carolina at Chapel Hill, Department of Environmental Sciences and Engineering, 166 Rosenau Hall, CB #7431, Chapel Hill, NC, 27599-7431, USA.
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Gonzales-Gustavson E, Rusiñol M, Medema G, Calvo M, Girones R. Quantitative risk assessment of norovirus and adenovirus for the use of reclaimed water to irrigate lettuce in Catalonia. WATER RESEARCH 2019; 153:91-99. [PMID: 30703677 DOI: 10.1016/j.watres.2018.12.070] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 09/22/2018] [Accepted: 12/31/2018] [Indexed: 05/21/2023]
Abstract
Wastewater is an important resource in water-scarce regions of the world, and its use in agriculture requires the guarantee of acceptable public health risks. The use of fecal indicator bacteria to evaluate safety does not represent viruses, the main potential health hazards. Viral pathogens could complement the use of fecal indicator bacteria in the evaluation of water quality. In this study, we characterized the concentration and removal of human adenovirus (HAdV) and norovirus genogroup II (NoV GII), highly abundant and important viral pathogens found in wastewater, in two wastewater treatment plants (WWTPs) that use different tertiary treatments (constructed wetland vs conventional UV, chlorination and Actiflo® treatments) for a year in Catalonia. The main objective of this study was to develop a Quantitative Microbial Risk Assessment for viral gastroenteritis caused by norovirus GII and adenovirus, associated with the ingestion of lettuce irrigated with tertiary effluents from these WWTPs. The results show that the disease burden of NoV GII and HAdV for the consumption of lettuce irrigated with tertiary effluent from either WWTP was higher than the WHO recommendation of 10-6 DALYs for both viruses. The WWTP with constructed wetland showed a higher viral reduction on average (3.9 and 2.8 logs for NoV GII and HAdV, respectively) than conventional treatment (1.9 and 2.5 logs) but a higher variability than the conventional WWTP. Sensitivity analysis demonstrated that the input parameters used to estimate the viral reduction by treatment and viral concentrations accounted for much of the model output variability. The estimated reductions required to reach the WHO recommended levels in tertiary effluent are influenced by the characteristics of the treatments developed in the WWTPs, and additional average reductions are necessary (in WWTP with a constructed wetland: A total of 6.7 and 5.1 logs for NoV GII and HAdV, respectively; and in the more conventional treatment: 7 and 5.6 logs). This recommendation would be achieved with an average quantification of 0.5 genome copies per 100 mL in reclaimed water for both viruses. The results suggest that the analyzed reclaimed water would require additional treatments to achieve acceptable risk in the irrigation of vegetables with reclaimed water.
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Affiliation(s)
- Eloy Gonzales-Gustavson
- Laboratory of Virus Contaminants of Water and Food, Section of Microbiology, Virology and Biotechnology, Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Avinguda Diagonal 643, 08028, Barcelona, Catalonia, Spain; Tropical and Highlands Veterinary Research Institute, School of Veterinary Medicine, San Marcos University, Carretera Central s/n, El Mantaro, Peru.
| | - Marta Rusiñol
- Laboratory of Virus Contaminants of Water and Food, Section of Microbiology, Virology and Biotechnology, Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Avinguda Diagonal 643, 08028, Barcelona, Catalonia, Spain.
| | - Gertjan Medema
- KWR Watercycle Research Institute, P.O. Box 1072, 3430, BB Nieuwegein, the Netherlands; The Netherlands and Delft University of Technology, the Netherlands.
| | - Miquel Calvo
- Section of Statistics, Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Avinguda Diagonal 643, 08028, Barcelona, Catalonia, Spain.
| | - Rosina Girones
- Laboratory of Virus Contaminants of Water and Food, Section of Microbiology, Virology and Biotechnology, Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Avinguda Diagonal 643, 08028, Barcelona, Catalonia, Spain.
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Burch T. Validation of Quantitative Microbial Risk Assessment Using Epidemiological Data from Outbreaks of Waterborne Gastrointestinal Disease. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2019; 39:599-615. [PMID: 30286512 DOI: 10.1111/risa.13189] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 08/06/2018] [Accepted: 08/20/2018] [Indexed: 05/20/2023]
Abstract
The assumptions underlying quantitative microbial risk assessment (QMRA) are simple and biologically plausible, but QMRA predictions have never been validated for many pathogens. The objective of this study was to validate QMRA predictions against epidemiological measurements from outbreaks of waterborne gastrointestinal disease. I screened 2,000 papers and identified 12 outbreaks with the necessary data: disease rates measured using epidemiological methods and pathogen concentrations measured in the source water. Eight of the 12 outbreaks were caused by Cryptosporidium, three by Giardia, and one by norovirus. Disease rates varied from 5.5 × 10-6 to 1.1 × 10-2 cases/person-day, and reported pathogen concentrations varied from 1.2 × 10-4 to 8.6 × 102 per liter. I used these concentrations with single-hit dose-response models for all three pathogens to conduct QMRA, producing both point and interval predictions of disease rates for each outbreak. Comparison of QMRA predictions to epidemiological measurements showed good agreement; interval predictions contained measured disease rates for 9 of 12 outbreaks, with point predictions off by factors of 1.0-120 (median = 4.8). Furthermore, 11 outbreaks occurred at mean doses of less than 1 pathogen per exposure. Measured disease rates for these outbreaks were clearly consistent with a single-hit model, and not with a "two-hit" threshold model. These results demonstrate the validity of QMRA for predicting disease rates due to Cryptosporidium and Giardia.
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Atanasova ND, Dey R, Scott C, Li Q, Pang XL, Ashbolt NJ. Persistence of infectious Enterovirus within free-living amoebae - A novel waterborne risk pathway? WATER RESEARCH 2018; 144:204-214. [PMID: 30031365 DOI: 10.1016/j.watres.2018.07.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 07/04/2018] [Accepted: 07/08/2018] [Indexed: 05/21/2023]
Abstract
Free-living amoebae (FLA) are phagocytic protozoa found in natural and engineered water systems. They can form disinfectant-resistant cysts, which can harbor various human pathogenic bacteria, therefore providing them with a means of environmental persistence and dispersion through water distribution and other engineered water systems. The association of FLA with human viruses has been raised, but the limited data on the persistence of infectious virions within amoebae leaves this aspect unresolved. Enteroviruses can cause a wide range of illness and replicate in human respiratory and gastrointestinal tracts, both of which could be exposed through contact with contaminated waters if virus detection and removal are compromised by virion internalization in free-living protozoa. This is especially problematic for high-risk contaminants, such as coxsackieviruses, representative members of the Enterovirus genus that are likely infectious at low doses and cause a variety of symptoms to a vulnerable portion of the population (particularly infants). To investigate Enterovirus persistence within free-living amoebae we co-cultured an infectious clinical coxsackievirus B5 (CVB5) isolate, with the commonly reported tap water amoeba Vermamoeba vermiformis, after which we tracked virus localization and persistence in co-culture over time through a combination of advanced imaging, molecular and cell culture assays. Our results clearly demonstrate that infectious CVB5 can persist in all life stages of the amoebae without causing any visible injury to them. We also demonstrated that the amoeba generated vesicles containing virions that were expelled into the bulk liquid surroundings, a finding previously described for FLA-bacteria interactions, but not for FLA and human pathogenic viruses. Therefore, our findings suggest that the ability of CVB5 to persist in V. vermiformis could be a novel waterborne risk pathway for the persistence and dispersion of infectious human enteric viruses through water systems.
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Affiliation(s)
- Nikki D Atanasova
- Dept. Medical Microbiology and Immunology, 6-020 Katz Group Centre, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Rafik Dey
- Dept. Medical Microbiology and Immunology, 6-020 Katz Group Centre, University of Alberta, Edmonton, AB, T6G 2E1, Canada; School of Public Health, Room 3-57D, South Academic Building, Edmonton, AB, T6G 2G7, Canada University of Alberta, Edmonton, Canada
| | - Candis Scott
- School of Public Health, Room 3-57D, South Academic Building, Edmonton, AB, T6G 2G7, Canada University of Alberta, Edmonton, Canada
| | - Qiaozhi Li
- School of Public Health, Room 3-57D, South Academic Building, Edmonton, AB, T6G 2G7, Canada University of Alberta, Edmonton, Canada
| | - Xiao-Li Pang
- Provincial Laboratory for Public Health, Edmonton, AB, T6G 2J2, Canada
| | - Nicholas J Ashbolt
- Dept. Medical Microbiology and Immunology, 6-020 Katz Group Centre, University of Alberta, Edmonton, AB, T6G 2E1, Canada; School of Public Health, Room 3-57D, South Academic Building, Edmonton, AB, T6G 2G7, Canada University of Alberta, Edmonton, Canada; Provincial Laboratory for Public Health, Edmonton, AB, T6G 2J2, Canada.
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Determination of Removal Efficiencies for Escherichia coli, Clostridial Spores, and F-Specific Coliphages in Unit Processes of Surface Waterworks for QMRA Applications. WATER 2018. [DOI: 10.3390/w10111525] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The removal efficiencies of bacteria, bacterial spores, and viruses after a change in source water and water pH in coagulation were studied at pilot scale in coagulation with flotation, rapid sand filtration, and disinfection with UV and chlorine. The results were compared to the treatment efficiencies of full-scale waterworks and data from literature. A quantitative microbial risk assessment (QMRA)-method was applied to estimate the numbers of illness cases caused by Campylobacter and norovirus after simulation of six operational malfunction scenarios. Coagulation with flotation and disinfection were more efficient in removing Clostridium spp. spores and MS2 coliphages than sand filtration in the pilot scale experiments (p < 0.001–0.008). The removal of E. coli was more efficient in sand filtration and in disinfection compared to coagulation with flotation (p = 0.006 and 0.01). Source water or pH change in coagulation had not significant effects on the removal efficiency of microbes. In QMRA, when disinfection was not in use, an increase in the number of illness cases compared to the normal situation was noticed. The variability in the number of illness cases demonstrated the importance of site-specific data in QMRA. This study provides new information on applying QMRA in both pilot and full-scale waterworks.
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Anastasopoulou A, Kolios A, Somorin T, Sowale A, Jiang Y, Fidalgo B, Parker A, Williams L, Collins M, McAdam E, Tyrrel S. Conceptual environmental impact assessment of a novel self-sustained sanitation system incorporating a quantitative microbial risk assessment approach. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 639:657-672. [PMID: 29800857 PMCID: PMC6021597 DOI: 10.1016/j.scitotenv.2018.05.062] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 05/04/2018] [Accepted: 05/05/2018] [Indexed: 05/24/2023]
Abstract
In many developing countries, including South Africa, water scarcity has resulted in poor sanitation practices. The majority of the sanitation infrastructures in those regions fail to meet basic hygienic standards. This along with the lack of proper sewage/wastewater infrastructure creates significant environmental and public health concerns. A self-sustained, waterless "Nano Membrane Toilet" (NMT) design was proposed as a result of the "Reinvent the Toilet Challenge" funded by the Bill and Melinda Gates Foundation. A "cradle-to-grave" life cycle assessment (LCA) approach was adopted to study the use of NMT in comparison with conventional pour flush toilet (PFT) and urine-diverting dry toilet (UDDT). All three scenarios were applied in the context of South Africa. In addition, a Quantitative Microbial Risk Assessment (QMRA) was used to reflect the impact of the pathogen risk on human health. LCA study showed that UDDT had the best environmental performance, followed by NMT and PFT systems for all impact categories investigated including human health, resource and ecosystem. This was mainly due to the environmental credits associated with the use of urine and compost as fertilizers. However, with the incorporation of the pathogen impact into the human health impact category, the NMT had a significant better performance than the PFT and UDDT systems, which exhibited an impact category value 4E + 04 and 4E + 03 times higher, respectively. Sensitivity analysis identified that the use of ash as fertilizer, electricity generation and the reduction of NOx emissions were the key areas that influenced significantly the environmental performance of the NMT system.
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Affiliation(s)
| | - Athanasios Kolios
- School of Water, Energy and Environment, Cranfield University, MK43 0AL, UK.
| | - Tosin Somorin
- School of Water, Energy and Environment, Cranfield University, MK43 0AL, UK.
| | - Ayodeji Sowale
- School of Water, Energy and Environment, Cranfield University, MK43 0AL, UK.
| | - Ying Jiang
- School of Water, Energy and Environment, Cranfield University, MK43 0AL, UK.
| | - Beatriz Fidalgo
- School of Water, Energy and Environment, Cranfield University, MK43 0AL, UK.
| | - Alison Parker
- School of Water, Energy and Environment, Cranfield University, MK43 0AL, UK.
| | - Leon Williams
- School of Water, Energy and Environment, Cranfield University, MK43 0AL, UK.
| | - Matt Collins
- School of Water, Energy and Environment, Cranfield University, MK43 0AL, UK.
| | - Ewan McAdam
- School of Water, Energy and Environment, Cranfield University, MK43 0AL, UK.
| | - Sean Tyrrel
- School of Water, Energy and Environment, Cranfield University, MK43 0AL, UK.
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Schoen ME, Jahne MA, Garland J. Human health impact of non-potable reuse of distributed wastewater and greywater treated by membrane bioreactors. MICROBIAL RISK ANALYSIS 2018; 9:72-81. [PMID: 35280215 PMCID: PMC8914979 DOI: 10.1016/j.mran.2018.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We assessed the annual probability of infection resulting from non-potable exposures to distributed greywater and domestic wastewater treated by an aerobic membrane bioreactor (MBR) followed by chlorination. A probabilistic quantitative microbial risk assessment was conducted for both residential and office buildings and a residential district using Norovirus, Rotavirus, Campylobacter jejuni, and Cryptosporidium spp. as reference pathogens. A Monte Carlo approach captured variation in pathogen concentration in the collected water and pathogen (or microbial surrogate) treatment performance, when available, for various source water and collection scale combinations. Uncertain inputs such as dose-response relationships and the volume ingested were treated deterministically and explored through sensitivity analysis. The predicted 95th percentile annual risks for non-potable indoor reuse of distributed greywater and domestic wastewater at district and building scales were less than the selected health benchmark of 10-4 infections per person per year (ppy) for all pathogens except Cryptosporidium spp., given the selected exposure (which included occasional, accidental ingestion), dose-response, and treatment performance assumptions. For Cryptosporidium spp., the 95th percentile annual risks for reuse of domestic wastewater (for all selected collection scenarios) and district-collected greywater were greater than the selected health benchmark when using the limited, available MBR treatment performance data; this finding is counterintuitive given the large size of Cryptosporidium spp. relative to the MBR pores. Therefore, additional data on MBR removal of protozoa is required to evaluate the proposed MBR treatment process for non-potable reuse. Although the predicted Norovirus annual risks were small across scenarios (less than 10-7 infections ppy), the risks for Norovirus remain uncertain, in part because the treatment performance is difficult to interpret given that the ratio of total to infectious viruses in the raw and treated effluents remains unknown. Overall, the differences in pathogen characterization between collection type (i.e., office vs. residential) and scale (i.e., district vs. building) drove the differences in predicted risk; and, the accidental ingestion event (although modeled as rare) determined the annual probability of infection. The predicted risks resulting from treatment malfunction scenarios indicated that online, real-time monitoring of both the MBR and disinfection processes remains important for non-potable reuse at distributed scales. The resulting predicted health risks provide insight on the suitability of MBR treatment for distributed, non-potable reuse at different collection scales and the potential to reduce health risks for non-potable reuse.
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Affiliation(s)
- Mary E. Schoen
- Soller Environmental, LLC, 3022 King St., Berkeley, CA 94703, USA
- Corresponding author. (M.E. Schoen)
| | - Michael A. Jahne
- U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati, OH 45268, USA
| | - Jay Garland
- U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati, OH 45268, USA
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38
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Quantitative Microbial Risk Assessment and Opportunist Waterborne Infections⁻Are There Too Many Gaps to Fill? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15061150. [PMID: 29865180 PMCID: PMC6025005 DOI: 10.3390/ijerph15061150] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 05/29/2018] [Accepted: 05/30/2018] [Indexed: 01/14/2023]
Abstract
Quantitative microbial risk assessment (QMRA) is a relatively new approach in identifying health risks associated with the ubiquitous presence of pathogens and opportunists in the human environment. The methodology builds on experimental and meta-analytical data to identify measurable factors that contribute to, and can quantify, the likely extent of disease given a particular exposure. Early modelling was particularly focused on food-borne disease, and subsequently water-borne disease, with the emphasis focused on ingestion and its role in enteric disease. More recently, there has been a focus on translating these principles to opportunist waterborne infections (OWI) with primary focus on Legionella spp. Whereas dose and susceptibility are well documented via the ingestion route of exposure there is considerably less certainty regarding both factors when understanding Legionella spp. and other OWI. Many OWI can arise through numerous routes of transmission with greatly differing disease presentations. Routes of Legionella spp. infection do not include ingestion, but rather aspiration and inhalation of contaminated water are the routes of exposure. The susceptible population for OWI is a vulnerable sub-set of the population unlike those associated with enteric disease pathogens. These variabilities in dose, exposure and susceptibility call in to question whether QMRA can be a useful tool in managing risks associated with OWI. Consideration of Legionella spp. as a well-documented subject of research calls into question whether QMRA of OWI is likely to be a useful tool in developing risk management strategies.
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Besmer MD, Hammes F, Sigrist JA, Ort C. Evaluating Monitoring Strategies to Detect Precipitation-Induced Microbial Contamination Events in Karstic Springs Used for Drinking Water. Front Microbiol 2017; 8:2229. [PMID: 29213255 PMCID: PMC5703154 DOI: 10.3389/fmicb.2017.02229] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/30/2017] [Indexed: 01/15/2023] Open
Abstract
Monitoring of microbial drinking water quality is a key component for ensuring safety and understanding risk, but conventional monitoring strategies are typically based on low sampling frequencies (e.g., quarterly or monthly). This is of concern because many drinking water sources, such as karstic springs are often subject to changes in bacterial concentrations on much shorter time scales (e.g., hours to days), for example after precipitation events. Microbial contamination events are crucial from a risk assessment perspective and should therefore be targeted by monitoring strategies to establish both the frequency of their occurrence and the magnitude of bacterial peak concentrations. In this study we used monitoring data from two specific karstic springs. We assessed the performance of conventional monitoring based on historical records and tested a number of alternative strategies based on a high-resolution data set of bacterial concentrations in spring water collected with online flow cytometry (FCM). We quantified the effect of increasing sampling frequency and found that for the specific case studied, at least bi-weekly sampling would be needed to detect precipitation events with a probability of >90%. We then proposed an optimized monitoring strategy with three targeted samples per event, triggered by precipitation measurements. This approach is more effective and efficient than simply increasing overall sampling frequency. It would enable the water utility to (1) analyze any relevant event and (2) limit median underestimation of peak concentrations to approximately 10%. We conclude with a generalized perspective on sampling optimization and argue that the assessment of short-term dynamics causing microbial peak loads initially requires increased sampling/analysis efforts, but can be optimized subsequently to account for limited resources. This offers water utilities and public health authorities systematic ways to evaluate and optimize their current monitoring strategies.
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Affiliation(s)
- Michael D Besmer
- Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.,Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Zurich, Switzerland
| | - Frederik Hammes
- Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Jürg A Sigrist
- Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Christoph Ort
- Department of Urban Water Management, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
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Vikesland PJ, Pruden A, Alvarez PJJ, Aga D, Bürgmann H, Li XD, Manaia CM, Nambi I, Wigginton K, Zhang T, Zhu YG. Toward a Comprehensive Strategy to Mitigate Dissemination of Environmental Sources of Antibiotic Resistance. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:13061-13069. [PMID: 28976743 DOI: 10.1021/acs.est.7b03623] [Citation(s) in RCA: 174] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Antibiotic resistance is a pervasive global health threat. To combat the spread of resistance, it is necessary to consider all possible sources and understand the pathways and mechanisms by which resistance disseminates. Best management practices are urgently needed to provide barriers to the spread of resistance and maximize the lifespan of antibiotics as a precious resource. Herein we advise upon the need for coordinated national and international strategies, highlighting three essential components: (1) Monitoring, (2) Risk Assessment, and (3) Mitigation of antibiotic resistance. Central to all three components is What exactly to monitor, assess, and mitigate? We address this question within an environmental framework, drawing from fundamental microbial ecological processes driving the spread of resistance.
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Affiliation(s)
- Peter J Vikesland
- Department of Civil and Environmental Engineering, Virginia Tech , Blacksburg, Virginia United States
- Virginia Tech Global Change Center and Virginia Tech Institute of Critical Technology and Applied Science, Virginia Tech , Blacksburg, Virginia United States
| | - Amy Pruden
- Department of Civil and Environmental Engineering, Virginia Tech , Blacksburg, Virginia United States
- Virginia Tech Global Change Center and Virginia Tech Institute of Critical Technology and Applied Science, Virginia Tech , Blacksburg, Virginia United States
| | - Pedro J J Alvarez
- Department of Civil and Environmental Engineering, Rice University , Houston, Texas United States
| | - Diana Aga
- Department of Chemistry, University at Buffalo , Buffalo, New York United States
| | - Helmut Bürgmann
- Eawag: Swiss Federal Institute of Aquatic Science and Technology , 6047 Kastanienbaum, Switzerland
| | - Xiang-Dong Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University , Hong Kong
| | - Celia M Manaia
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia , Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal
| | - Indumathi Nambi
- Department of Civil Engineering, Indian Institute of Technology - Madras , Chennai, India
| | - Krista Wigginton
- Department of Civil and Environmental Engineering, The University of Michigan , Ann Arbor, Michigan United States
| | - Tong Zhang
- Department of Civil Engineering, Hong Kong University , Hong Kong
| | - Yong-Guan Zhu
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences , Xiamen 361021, China
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Amoueyan E, Ahmad S, Eisenberg JNS, Pecson B, Gerrity D. Quantifying pathogen risks associated with potable reuse: A risk assessment case study for Cryptosporidium. WATER RESEARCH 2017; 119:252-266. [PMID: 28475966 DOI: 10.1016/j.watres.2017.04.048] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 04/12/2017] [Accepted: 04/18/2017] [Indexed: 06/07/2023]
Abstract
This study evaluated the reliability and equivalency of three different potable reuse paradigms: (1) surface water augmentation via de facto reuse with conventional wastewater treatment; (2) surface water augmentation via planned indirect potable reuse (IPR) with ultrafiltration, pre-ozone, biological activated carbon (BAC), and post-ozone; and (3) direct potable reuse (DPR) with ultrafiltration, ozone, BAC, and UV disinfection. A quantitative microbial risk assessment (QMRA) was performed to (1) quantify the risk of infection from Cryptosporidium oocysts; (2) compare the risks associated with different potable reuse systems under optimal and sub-optimal conditions; and (3) identify critical model/operational parameters based on sensitivity analyses. The annual risks of infection associated with the de facto and planned IPR systems were generally consistent with those of conventional drinking water systems [mean of (9.4 ± 0.3) × 10-5 to (4.5 ± 0.1) × 10-4], while DPR was clearly superior [mean of (6.1 ± 67) × 10-9 during sub-optimal operation]. Because the advanced treatment train in the planned IPR system was highly effective in reducing Cryptosporidium concentrations, the associated risks were generally dominated by the pathogen loading already present in the surface water. As a result, risks generally decreased with higher recycled water contributions (RWCs). Advanced treatment failures were generally inconsequential either due to the robustness of the advanced treatment train (i.e., DPR) or resiliency provided by the environmental buffer (i.e., planned IPR). Storage time in the environmental buffer was important for the de facto reuse system, and the model indicated a critical storage time of approximately 105 days. Storage times shorter than the critical value resulted in significant increases in risk. The conclusions from this study can be used to inform regulatory decision making and aid in the development of design or operational criteria for IPR and DPR systems.
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Affiliation(s)
- Erfaneh Amoueyan
- Department of Civil and Environmental Engineering and Construction, University of Nevada, Las Vegas, Box 454015, 4505 S. Maryland Parkway, Las Vegas, NV 89154-4015, United States
| | - Sajjad Ahmad
- Department of Civil and Environmental Engineering and Construction, University of Nevada, Las Vegas, Box 454015, 4505 S. Maryland Parkway, Las Vegas, NV 89154-4015, United States
| | - Joseph N S Eisenberg
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, United States
| | - Brian Pecson
- Trussell Technologies, Inc., Pasadena, CA, United States
| | - Daniel Gerrity
- Department of Civil and Environmental Engineering and Construction, University of Nevada, Las Vegas, Box 454015, 4505 S. Maryland Parkway, Las Vegas, NV 89154-4015, United States.
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42
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Schoen ME, Ashbolt NJ, Jahne MA, Garland J. Risk-based enteric pathogen reduction targets for non-potable and direct potable use of roof runoff, stormwater, and greywater. MICROBIAL RISK ANALYSIS 2017; 5:32-43. [PMID: 31534999 PMCID: PMC6750756 DOI: 10.1016/j.mran.2017.01.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
This paper presents risk-based enteric pathogen log reduction targets for non-potable and potable uses of a variety of alternative source waters (i.e., locally-collected greywater, roof runoff, and stormwater). A probabilistic Quantitative Microbial Risk Assessment (QMRA) was used to derive the pathogen log10 reduction targets (LRTs) that corresponded with an infection risk of either 10-4 per person per year (ppy) or 10-2 ppy. The QMRA accounted for variation in pathogen concentration and sporadic pathogen occurrence (when data were available) in source waters for reference pathogens in the genera Rotavirus, Mastadenovirus(human adenoviruses), Norovirus, Campylobacter, Salmonella, Giardia and Cryptosporidium. Non-potable uses included indoor use (for toilet flushing and clothes washing) with occasional accidental ingestion of treated non-potable water (or cross-connection with potable water), and unrestricted irrigation for outdoor use. Various exposure scenarios captured the uncertainty from key inputs, i.e., the pathogen concentration in source water; the volume of water ingested; and for the indoor use, the frequency of and the fraction of the population exposed to accidental ingestion. Both potable and non-potable uses required pathogen treatment for the selected waters and the LRT was generally greater for potable use than non-potable indoor use and unrestricted irrigation. The difference in treatment requirements among source waters was driven by the microbial quality of the water - both the density and occurrence of reference pathogens. Greywater from collection systems with 1000 people had the highest LRTs; however, those for greywater collected from a smaller population (~ 5 people), which have less frequent pathogen occurrences, were lower. Stormwater had highly variable microbial quality, which resulted in a range of possible treatment requirements. The microbial quality of roof runoff, and thus the resulting LRTs, remains uncertain due to lack of relevant pathogen data.
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Affiliation(s)
- Mary E Schoen
- Soller Environmental, Inc., 3022 King St., Berkeley, CA 94703, USA
| | - Nicholas J Ashbolt
- Rm. 3-57D South Academic Building, School of Public Health, University of Alberta, Edmonton AB T6G 2G7, Canada
| | - Michael A Jahne
- U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati OH 45268, USA
| | - Jay Garland
- U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati OH 45268, USA
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