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Ayeta EG, Yafetto L, Lutterodt G, Ogbonna JF, Miyittah MK. Seasonal variations and health risk assessment of microbial contaminations of groundwater in selected coastal communities of Ghana. Heliyon 2023; 9:e18761. [PMID: 37576282 PMCID: PMC10415664 DOI: 10.1016/j.heliyon.2023.e18761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 07/26/2023] [Accepted: 07/26/2023] [Indexed: 08/15/2023] Open
Abstract
This study investigated seasonal variations in microbial contaminations of groundwater and associated health risks in four coastal communities (Essiama, Winneba, Accra, and Keta) in Ghana. Membrane filtration methods, sanitary risk inspection, and quantitative microbial risk assessment were employed, respectively, to (i) quantify bacteriological quality, (ii) identify risks to contamination, and (iii) assess health risks associated with Escherichia coli in groundwater. Results showed 70.00%, 53.33%, 70.37% and 90.00% of groundwater sources in Essiama, Winneba, Accra, and Keta, respectively, were at intermediate risk, whereas 3.33%, 40.00%, 14.81%, and 3.33%, respectively, were at high risk. Very high-risk levels of contamination were recorded only in Accra. The presence of animal wastes within a 10 m radius of groundwater collection point, bad drainage systems, collection of spilt water in apron area, the use of ropes and buckets when fetching groundwater, and absence of aprons and well covers put more than 60.00% of the groundwater points in two or more locations at risk of contaminations. Assessment of bacteriological quality of groundwater indicated that mean total coliforms and E. coli ranged, respectively, between 123.40-501.30 and 30.98-141.90 CFU/100 ml for the communities; the highest microbial counts for dry and wet seasons occurred in Winneba and Keta, respectively. Seasonal variations in E. coli counts in Winneba and Accra were significantly higher in the dry season than in the wet season; Essiama and Keta showed no significant seasonal variations. Exposure to E. coli O157:H7 through drinking groundwater ranged between 5 and 23 cells per day. Although exposure to E. coli O157:H7 through bathing was less than 1 cell per day in all communities, residents were exposed to one E. coli, at least, every 62, 141, 237, and 282 days in Winneba, Accra, Keta, and Essiama, respectively. The risk of infection and illness for all communities was 1 for drinking, whereas that for bathing ranged from 0.57 to 0.98. The estimated Disability-Adjusted Life Years (DALY) exceeded the WHO-acceptable DALY. These findings show that groundwater resources in the selected coastal communities were prone to microbial contaminations, and this may be a setback to Sustainable Development Goals 6. Implications of the findings are discussed.
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Affiliation(s)
- Emuobonuvie G. Ayeta
- Centre for Coastal Management, Africa Centre of Excellence in Coastal Resilience, University of Cape Coast, Cape Coast, Ghana
- Department of Fisheries and Aquatic Sciences, School of Biological Sciences, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Levi Yafetto
- Department of Molecular Biology and Biotechnology, School of Biological Sciences, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast, Ghana
| | - George Lutterodt
- Department of Water Resources and Aquaculture Management, School of Sustainable Development, University of Environment and Sustainable Development, Somanya, Ghana
| | - Joel F. Ogbonna
- World Bank Africa Centre of Excellence for Oil Field Chemicals Research, University of Port Harcourt, Choba, Nigeria
| | - Michael K. Miyittah
- Department of Environmental Science, School of Biological Sciences, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast, Ghana
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Petterson S, Bradford-Hartke Z, Leask S, Jarvis L, Wall K, Byleveld P. Application of QMRA to prioritise water supplies for Cryptosporidium risk in New South Wales, Australia. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 784:147107. [PMID: 34088069 DOI: 10.1016/j.scitotenv.2021.147107] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/31/2021] [Accepted: 04/09/2021] [Indexed: 06/12/2023]
Abstract
A Quantitative Microbial Risk Assessment (QMRA) framework was applied to assess 312 drinking water supply systems across regional New South Wales (NSW). The framework was needed to support the implementation of a recommendation in the Australian Drinking Water Guidelines (ADWG) for appropriate treatment barriers to be operating in systems 'at risk' for Cryptosporidium. The objective was to prioritise systems so that those with the highest risk could be identified and addressed first. The framework was developed in a pilot study of 30 systems, selected to represent the range of water supplies across regional NSW. From these, source water categories were defined to represent local conditions with reference to the literature and Cryptosporidium risk factors. Values for Cryptosporidium oocyst concentration were assigned to the categories to allow quantification of the health risk from those water sources. The framework was then used to assess the risks in all 312 regional drinking water supply systems. Combining the disciplined approach of QMRA with simple catchment and treatment information and categorical risk outputs provided a useful and transparent method for prioritising systems for further investigation and potential risk management intervention. The risk rankings for drinking water supplies from this QMRA process have been used to set priorities for a large State Government funding program.
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Affiliation(s)
- S Petterson
- Water& Health Pty Ltd, North Sydney, Australia; School of Medicine, Griffith University, Australia.
| | - Z Bradford-Hartke
- Water Unit, Environmental Health Branch, NSW Health, St Leonards, Australia
| | - S Leask
- Water Unit, Environmental Health Branch, NSW Health, St Leonards, Australia
| | - L Jarvis
- Water Unit, Environmental Health Branch, NSW Health, St Leonards, Australia
| | - K Wall
- Water Unit, Environmental Health Branch, NSW Health, St Leonards, Australia
| | - P Byleveld
- Water Unit, Environmental Health Branch, NSW Health, St Leonards, Australia
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Sylvestre É, Prévost M, Smeets P, Medema G, Burnet JB, Cantin P, Villion M, Robert C, Dorner S. Importance of Distributional Forms for the Assessment of Protozoan Pathogens Concentrations in Drinking-Water Sources. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2021; 41:1396-1412. [PMID: 33103818 DOI: 10.1111/risa.13613] [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: 03/24/2020] [Revised: 09/18/2020] [Accepted: 10/02/2020] [Indexed: 06/11/2023]
Abstract
The identification of appropriately conservative statistical distributions is needed to predict microbial peak events in drinking water sources explicitly. In this study, Poisson and mixed Poisson distributions with different upper tail behaviors were used for modeling source water Cryptosporidium and Giardia data from 30 drinking water treatment plants. Small differences (<0.5-log) were found between the "best" estimates of the mean Cryptosporidium and Giardia concentrations with the Poisson-gamma and Poisson-log-normal models. However, the upper bound of the 95% credibility interval on the mean Cryptosporidium concentrations of the Poisson-log-normal model was considerably higher (>0.5-log) than that of the Poisson-gamma model at four sites. The improper choice of a model may, therefore, mislead the assessment of treatment requirements and health risks associated with the water supply. Discrimination between models using the marginal deviance information criterion (mDIC) was unachievable because differences in upper tail behaviors were not well characterized with available data sets ( n<30 ). Therefore, the gamma and the log-normal distributions fit the data equally well but may predict different risk estimates when they are used as an input distribution in an exposure assessment. The collection of event-based monitoring data and the modeling of larger routine monitoring data sets are recommended to identify appropriately conservative distributions to predict microbial peak events.
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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
| | - Patrick Smeets
- KWR Water Research Institute, Groningenhaven 7, Nieuwegein, 3433 PE, The Netherlands
| | - Gertjan Medema
- KWR Water Research Institute, Groningenhaven 7, Nieuwegein, 3433 PE, The Netherlands
- Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, Delft, 2600GA, The Netherlands
| | - 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
| | - Philippe Cantin
- Ministère de l'Environnement et de la Lutte contre les changements climatiques, Québec, Canada
| | - Manuela Villion
- Centre d'expertise en analyse environnementale du Québec, Ministère de l'Environnement et de la Lutte contre les changements climatiques, Québec, Canada
| | - Caroline Robert
- Ministère de l'Environnement et de la Lutte contre les changements climatiques, Québec, 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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Kozak S, Petterson S, McAlister T, Jennison I, Bagraith S, Roiko A. Utility of QMRA to compare health risks associated with alternative urban sewer overflow management strategies. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 262:110309. [PMID: 32250792 DOI: 10.1016/j.jenvman.2020.110309] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 01/10/2020] [Accepted: 02/18/2020] [Indexed: 06/11/2023]
Abstract
Wet weather sewer overflows pose potential short-term public health risks. With increasing populations, aging infrastructure and climate change, utilities are challenged with managing sewerage infrastructure to provide optimum outcomes. This study compared how modelled public health risk profiles could change under alternative sewer overflow management strategies during 12 and 24-month rainfall-runoff events. Specifically, existing conditions were compared with both a 'business-as-usual' (BAU) sewer upgrade and a more holistic 'effects-based planning' (EBP) approach based on pumped wet weather sewage overflows directed to a local receiving waterway. Options were compared based on their efficacy to reduce manhole overflows, recreational waterway guideline exceedances and downstream recreational waterway health risks estimated through a screening-level Quantitative Microbial Risk Assessment (QMRA). Results indicated that the two management strategies would be equally effective in reducing the frequency, duration and volume of manhole sewer overflows, eliminating them in the 12-month scenarios and reducing them from >5000 m3 for the 24-month baseline scenario, to 23 and 35 m3 for BAU and EBP, respectively. Baseline, BAU and EBP scenarios produced similar hours of enterococci guideline exceedances, ranging from 1 to 4 h difference. The QMRA produced similar health risk profiles for downstream recreational waterway users for all design events, suggesting that sewer overflows are not the primary driver of public health risks during and immediately following high rainfall events. As such, QMRA provided evidence that an EBP strategy may be used to manage wet weather sewer overflows in lieu of an expensive BAU upgrade, without exacerbating the public health of downstream waterway users. Further investigation of the broader environmental health impacts of implementing this type of innovative approach is warranted. Nonetheless, this work highlights the value of integrating QMRA with other modelling approaches to guide and inform sewer overflow management.
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Affiliation(s)
- Sonya Kozak
- School of Medicine, Griffith University, Parklands Drive, Gold Coast, Australia; Cities Research Institute, Griffith University, Parklands Drive, Gold Coast, Australia.
| | - Susan Petterson
- School of Medicine, Griffith University, Parklands Drive, Gold Coast, Australia; Water & Health Pty Ltd, P.O. 648, Salamander Bay, 2317, Australia.
| | - Tony McAlister
- School of Medicine, Griffith University, Parklands Drive, Gold Coast, Australia; Water Technology, Level 3, 43 Peel Street, South Brisbane, QLD, Australia.
| | - Ian Jennison
- Queensland Urban Utilities, 2/15 Green Square Close, Brisbane, Australia.
| | - Sam Bagraith
- Queensland Urban Utilities, 2/15 Green Square Close, Brisbane, Australia.
| | - Anne Roiko
- School of Medicine, Griffith University, Parklands Drive, Gold Coast, Australia; Cities Research Institute, Griffith University, Parklands Drive, Gold Coast, Australia.
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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: 41] [Impact Index Per Article: 10.3] [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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Sylvestre É, Burnet JB, Smeets P, Medema G, Prévost M, Dorner S. Can routine monitoring of E. coli fully account for peak event concentrations at drinking water intakes in agricultural and urban rivers? WATER RESEARCH 2020; 170:115369. [PMID: 31830653 DOI: 10.1016/j.watres.2019.115369] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 11/25/2019] [Accepted: 12/02/2019] [Indexed: 06/10/2023]
Abstract
In several jurisdictions, the arithmetic mean of Escherichia coli concentrations in raw water serves as the metric to set minimal treatment requirements by drinking water treatment plants (DWTPs). An accurate and precise estimation of this mean is therefore critical to define adequate requirements. Distributions of E. coli concentrations in surface water can be heavily skewed and require statistical methods capable of characterizing uncertainty. We present four simple parametric models with different upper tail behaviors (gamma, log-normal, Lomax, mixture of two log-normal distributions) to explicitly account for the influence of peak events on the mean concentration. The performance of these models was tested using large E. coli data sets (200-1800 samples) from raw water regulatory monitoring at six DWTPs located in urban and agricultural catchments. Critical seasons of contamination and hydrometeorological factors leading to peak events were identified. Event-based samples were collected at an urban DWTP intake during two hydrometeorological events using online β-d-glucuronidase activity monitoring as a trigger. Results from event-based sampling were used to verify whether selected parametric distributions predicted targeted peak events. We found that the upper tail of the log-normal and the Lomax distributions better predicted large concentrations than the upper tail of the gamma distribution. Weekly sampling for two years in urban catchments and for four years in agricultural catchments generated reasonable estimates of the average raw water E. coli concentrations. The proposed methodology can be easily used to inform the development of sampling strategies and statistical indices to set site-specific treatment requirements.
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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.
| | - 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 Watercycle Research Institute, Groningenhaven 7, 3433, PE Nieuwegein, the Netherlands
| | - Gertjan Medema
- KWR Watercycle 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
| | - Michèle Prévost
- NSERC Industrial Chair on Drinking Water, 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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Taghipour M, Shakibaeinia A, Sylvestre É, Tolouei S, Dorner S. Microbial risk associated with CSOs upstream of drinking water sources in a transboundary river using hydrodynamic and water quality modeling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 683:547-558. [PMID: 31146060 DOI: 10.1016/j.scitotenv.2019.05.130] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/08/2019] [Accepted: 05/09/2019] [Indexed: 06/09/2023]
Abstract
Urban source water protection planning requires the characterization of sources of contamination upstream of drinking water intakes. Elevated pathogen concentrations following Combined Sewer Overflows (CSOs) represent a threat to human health. Quantifying peak pathogen concentrations at the intakes of drinking water plants is a challenge due to the variability of CSO occurrences and uncertainties with regards to the fate and transport mechanisms from discharge points to source water supplies. Here, a two-dimensional deterministic hydrodynamic and water quality model is used to study the fluvial contaminant transport and the impacts of the upstream CSO discharges on the downstream concentrations of Escherichia coli in the raw water supply of two drinking water plants, located on a large river. CSO dynamic loading characteristics were considered for a variety of discharges. As a result of limited Cryptosporidium data, a probability distribution of the ratio of E. coli to Cryptosporidium based on historical data was used to estimate microbial risk from simulated CSO-induced E. coli concentrations. During optimal operational performance of the plants, the daily risk target was met (based on the mean concentration during the peak) for 80% to 90% of CSO events. For suboptimal performance of the plants, these values dropped to 40% to 55%. Mean annual microbial risk following CSO discharge events was more dependent on treatment performance rather than the number of CSO occurrences. The effect of CSO-associated short term risk on the mean annual risk is largely dependent on the treatment performance as well as representativeness of the baseline condition at the intakes, demonstrating the need for assessment of treatment efficacy. The results of this study will enable water utilities and managers with a tool to investigate the potential alternatives in reducing the microbial risk associated with CSOs.
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Affiliation(s)
- Milad Taghipour
- Civil, Geological and Mining Engineering, Polytechnique Montréal, C.P.6079, Station Centre-ville, Montréal, Québec H3C 3A7, Canada.
| | - Ahmad Shakibaeinia
- Civil, Geological and Mining Engineering, Polytechnique Montréal, C.P.6079, Station Centre-ville, Montréal, Québec H3C 3A7, Canada
| | - Émile Sylvestre
- Civil, Geological and Mining Engineering, Polytechnique Montréal, C.P.6079, Station Centre-ville, Montréal, Québec H3C 3A7, Canada; NSERC Industrial Chair on Drinking Water, Polytechnique Montréal, P.O. Box 6079, Station Centre-ville, Montréal, Québec H3C 3A7, Canada
| | - Samira Tolouei
- Civil, Geological and Mining Engineering, Polytechnique Montréal, C.P.6079, Station Centre-ville, Montréal, Québec H3C 3A7, Canada; NSERC Industrial Chair on Drinking Water, Polytechnique Montréal, P.O. Box 6079, Station Centre-ville, Montréal, Québec H3C 3A7, Canada
| | - Sarah Dorner
- Civil, Geological and Mining Engineering, Polytechnique Montréal, C.P.6079, Station Centre-ville, Montréal, Québec H3C 3A7, Canada
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Swaffer B, Abbott H, King B, van der Linden L, Monis P. Understanding human infectious Cryptosporidium risk in drinking water supply catchments. WATER RESEARCH 2018; 138:282-292. [PMID: 29614456 DOI: 10.1016/j.watres.2018.03.063] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 03/21/2018] [Accepted: 03/26/2018] [Indexed: 05/22/2023]
Abstract
Treating drinking water appropriately depends, in part, on the robustness of source water quality risk assessments, however quantifying the proportion of infectious, human pathogenic Cryptosporidium oocysts remains a significant challenge. We analysed 962 source water samples across nine locations to profile the occurrence, rate and timing of infectious, human pathogenic Cryptosporidium in surface waters entering drinking water reservoirs during rainfall-runoff conditions. At the catchment level, average infectivity over the four-year study period reached 18%; however, most locations averaged <5%. The maximum recorded infectivity fraction within a single rainfall runoff event was 65.4%, and was dominated by C. parvum. Twenty-two Cryptosporidium species and genotypes were identified using PCR-based molecular techniques; the most common being C. parvum, detected in 23% of water samples. Associations between landuse and livestock stocking characteristics with Cryptosporidium were determined using a linear mixed-effects model. The concentration of pathogens in water were significantly influenced by flow and dominance of land-use by commercial grazing properties (as opposed to lifestyle properties) in the catchment (p < 0.01). Inclusion of measured infectivity and human pathogenicity data into a quantitative microbial risk assessment (QMRA) could reduce the source water treatment requirements by up to 2.67 log removal values, depending on the catchment, and demonstrated the potential benefit of collating such data for QMRAs.
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Affiliation(s)
- Brooke Swaffer
- South Australia Water Corporation, GPO Box 1751, Adelaide, South Australia, 5001, Australia.
| | - Hayley Abbott
- South Australia Water Corporation, GPO Box 1751, Adelaide, South Australia, 5001, Australia
| | - Brendon King
- South Australia Water Corporation, GPO Box 1751, Adelaide, South Australia, 5001, Australia
| | - Leon van der Linden
- South Australia Water Corporation, GPO Box 1751, Adelaide, South Australia, 5001, Australia
| | - Paul Monis
- South Australia Water Corporation, GPO Box 1751, Adelaide, South Australia, 5001, Australia
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Petterson SR, Ashbolt NJ. QMRA and water safety management: review of application in drinking water systems. JOURNAL OF WATER AND HEALTH 2016; 14:571-589. [PMID: 27441853 DOI: 10.2166/wh.2016.262] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Quantitative microbial risk assessment (QMRA), the assessment of microbial risks when model inputs and estimated health impacts are explicitly quantified, is a valuable tool to support water safety plans (WSP). In this paper, research studies undertaken on the application of QMRA in drinking water systems were reviewed, highlighting their relevance for WSP. The important elements for practical implementation include: the data requirements to achieve sufficient certainty to support decision-making; level of expertise necessary to undertake the required analysis; and the accessibility of tools to support wider implementation, hence these aspects were the focus of the review. Recommendations to support the continued and growing application of QMRA to support risk management in the water sector are provided.
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Affiliation(s)
- S R Petterson
- Water & Health Pty Ltd, PO Box 648, Salamander Bay 2317, Australia E-mail:
| | - N J Ashbolt
- School of Public Health, University of Alberta, Alberta, Canada T6G 2G7
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10
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Petterson SR, Mitchell VG, Davies CM, O'Connor J, Kaucner C, Roser D, Ashbolt N. Evaluation of three full-scale stormwater treatment systems with respect to water yield, pathogen removal efficacy and human health risk from faecal pathogens. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 543:691-702. [PMID: 26615487 DOI: 10.1016/j.scitotenv.2015.11.056] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 11/10/2015] [Accepted: 11/10/2015] [Indexed: 05/20/2023]
Abstract
In this study, three full-scale, operational stormwater harvesting systems located in Melbourne, Australia were evaluated with respect to water yields; pathogen removal performance by analysis of native surrogate data (Escherichiacoli, somatic coliphages and Clostridium perfringens); and potential human health risk associated with exposures to faecal pathogens using Quantitative Microbial Risk Assessment (QMRA). The water yield assessment confirmed variation between design and measured yields. Faecal contamination of urban stormwater was site specific and variable. Different treatment removal performance was observed between each of the microbial surrogates and varied between event and baseline conditions, with negligible removal of viruses during event conditions. Open storages that provide a habitat for waterfowl may lead to elevated risk due to the potential for zoonotic transmission. Nevertheless, in the Australian urban setting studied, the potential for human faecal contamination of the separated stormwater system was a critical driver of risk. If the integrity of the sewerage system can be ensured, then predicted health risks are dramatically reduced.
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Affiliation(s)
- Susan R Petterson
- Water & Health Pty Ltd, P.O. Box 648, Salamander Bay 2317, Australia.
| | | | | | | | - Christine Kaucner
- Water Research Centre, School of Civil and Environmental Engineering, University of NSW, Australia
| | - David Roser
- Water Research Centre, School of Civil and Environmental Engineering, University of NSW, Australia
| | - Nicholas Ashbolt
- Water Research Centre, School of Civil and Environmental Engineering, University of NSW, Australia; School of Public Health, University of Alberta, Alberta T6G 2G7, Canada
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11
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Petterson S, Grøndahl-Rosado R, Nilsen V, Myrmel M, Robertson LJ. Variability in the recovery of a virus concentration procedure in water: Implications for QMRA. WATER RESEARCH 2015; 87:79-86. [PMID: 26383122 DOI: 10.1016/j.watres.2015.09.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 09/01/2015] [Accepted: 09/02/2015] [Indexed: 05/18/2023]
Abstract
Methods for analysing water for viruses are known to have variable and relatively poor recovery efficiencies. Quantitative method recovery data are needed to correct virus enumeration results so that estimates of virus concentrations in surface waters for QMRA are not too low. Obtaining quantitative data representing method recoveries for different pathogenic viruses is a significant challenge. In this study, we investigated the use of mengovirus process control data for quantifying recovery efficiency of human adenovirus (AdV) and noroviruses GI (NoVGI) and GII (NoVGII) from surface waters. Samples were collected from the inlet to a drinking water treatment plant on the Glomma River, Norway. Performance of the sample concentration procedure was quantified by comparing the virus concentrations found in concentrated and unconcentrated samples. The mean recovery of viruses (1.2%, 0.31%, 0.15% and 0.053% for mengovirus (n = 86), AdV (n = 20), NoVGI (n = 33) and NoVGII (n = 21) respectively) estimated in this study were lower than expected, and the between sample variability in estimated recovery was very high, spanning around 6 orders of magnitude for mengovirus. Within-sample correlation between the estimated recovery of mengovirus and human viruses was poor, and therefore sample specific mengovirus data could not be used to correct all human virus concentrations. Instead beta distributions were fitted to human virus-specific recovery estimates. The magnitude and variability of virus concentration when corrected for the variable recovery efficiency was orders of magnitude higher than the uncorrected concentration. Better estimates of virus concentration could be achieved if a sample-specific spiking control could be developed that mimicked closely the behaviour of human viruses in environmental samples.
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Affiliation(s)
- Susan Petterson
- Water & Health Pty Ltd. P.O. Box 648, Salamander Bay 2317, Australia; Department of Mathematical Sciences and Technology, Faculty of Environmental Science and Technology, Norwegian University of Life Sciences, Campus Ås, P.O. Box 5003, N-1432 ÅS, Norway.
| | - Ricardo Grøndahl-Rosado
- Department of Food Safety and Infection Biology, Faculty of Veterinary Science and Biomedicine, Norwegian University of Life Sciences, Campus Adamstuen, P.O. Box 8146 Dep., N-0033 Oslo, Norway
| | - Vegard Nilsen
- Department of Mathematical Sciences and Technology, Faculty of Environmental Science and Technology, Norwegian University of Life Sciences, Campus Ås, P.O. Box 5003, N-1432 ÅS, Norway
| | - Mette Myrmel
- Department of Food Safety and Infection Biology, Faculty of Veterinary Science and Biomedicine, Norwegian University of Life Sciences, Campus Adamstuen, P.O. Box 8146 Dep., N-0033 Oslo, Norway
| | - Lucy J Robertson
- Department of Food Safety and Infection Biology, Faculty of Veterinary Science and Biomedicine, Norwegian University of Life Sciences, Campus Adamstuen, P.O. Box 8146 Dep., N-0033 Oslo, Norway
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