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Hamilton KA, Ciol Harrison J, Mitchell J, Weir M, Verhougstraete M, Haas CN, Nejadhashemi AP, Libarkin J, Gim Aw T, Bibby K, Bivins A, Brown J, Dean K, Dunbar G, Eisenberg JNS, Emelko M, Gerrity D, Gurian PL, Hartnett E, Jahne M, Jones RM, Julian TR, Li H, Li Y, Gibson JM, Medema G, Meschke JS, Mraz A, Murphy H, Oryang D, Owusu-Ansah EDGJ, Pasek E, Pradhan AK, Razzolini MTP, Ryan MO, Schoen M, Smeets PWMH, Soller J, Solo-Gabriele H, Williams C, Wilson AM, Zimmer-Faust A, Alja'fari J, Rose JB. Research gaps and priorities for quantitative microbial risk assessment (QMRA). RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2024. [PMID: 38772724 DOI: 10.1111/risa.14318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 03/12/2024] [Accepted: 04/28/2024] [Indexed: 05/23/2024]
Abstract
The coronavirus disease 2019 pandemic highlighted the need for more rapid and routine application of modeling approaches such as quantitative microbial risk assessment (QMRA) for protecting public health. QMRA is a transdisciplinary science dedicated to understanding, predicting, and mitigating infectious disease risks. To better equip QMRA researchers to inform policy and public health management, an Advances in Research for QMRA workshop was held to synthesize a path forward for QMRA research. We summarize insights from 41 QMRA researchers and experts to clarify the role of QMRA in risk analysis by (1) identifying key research needs, (2) highlighting emerging applications of QMRA; and (3) describing data needs and key scientific efforts to improve the science of QMRA. Key identified research priorities included using molecular tools in QMRA, advancing dose-response methodology, addressing needed exposure assessments, harmonizing environmental monitoring for QMRA, unifying a divide between disease transmission and QMRA models, calibrating and/or validating QMRA models, modeling co-exposures and mixtures, and standardizing practices for incorporating variability and uncertainty throughout the source-to-outcome continuum. Cross-cutting needs identified were to: develop a community of research and practice, integrate QMRA with other scientific approaches, increase QMRA translation and impacts, build communication strategies, and encourage sustainable funding mechanisms. Ultimately, a vision for advancing the science of QMRA is outlined for informing national to global health assessments, controls, and policies.
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Affiliation(s)
- Kerry A Hamilton
- The Biodesign Institute Center for Environmental Health Engineering, Arizona State University, Tempe, Arizona, USA
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona, USA
| | - Joanna Ciol Harrison
- The Biodesign Institute Center for Environmental Health Engineering, Arizona State University, Tempe, Arizona, USA
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona, USA
| | - Jade Mitchell
- Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan, USA
| | - Mark Weir
- Division of Environmental Health Sciences and Sustainability Institute, The Ohio State University, Columbus, Ohio, USA
| | - Marc Verhougstraete
- Mel and Enid Zuckerman College of Public Health, The University of Arizona, Tucson, Arizona, USA
| | - Charles N Haas
- Department of Civil, Architectural, and Environmental Engineering, Drexel University, Philadelphia, Pennsylvania, USA
| | - A Pouyan Nejadhashemi
- Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan, USA
| | - Julie Libarkin
- Department of Earth and Environmental Sciences, Michigan State University, East Lansing, Michigan, USA
| | - Tiong Gim Aw
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA
| | - Kyle Bibby
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Aaron Bivins
- Department of Civil & Environmental Engineering, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Joe Brown
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Kara Dean
- Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan, USA
| | - Gwyneth Dunbar
- Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan, USA
| | - Joseph N S Eisenberg
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan, USA
| | - Monica Emelko
- Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Daniel Gerrity
- Applied Research and Development Center, Southern Nevada Water Authority, Las Vegas, Nevada, USA
| | - Patrick L Gurian
- Department of Civil, Architectural, and Environmental Engineering, Drexel University, Philadelphia, Pennsylvania, USA
| | | | - Michael Jahne
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Rachael M Jones
- Department of Environmental Health Sciences, Fielding School of Public Health, University of California, Los Angeles, California, USA
| | - Timothy R Julian
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Duebendorf, Switzerland
| | - Hongwan Li
- Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan, USA
| | - Yanbin Li
- Department of Biological and Agricultural Engineering, The University of Arkansas, Fayetteville, Arkansas, USA
| | - Jacqueline MacDonald Gibson
- Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - Gertjan Medema
- KWR Water Research Institute, Nieuwegein, The Netherlands
- TU Delft, Delft, The Netherlands
| | - J Scott Meschke
- Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, Washington, USA
| | - Alexis Mraz
- Department of Public Health, School of Nursing, Health and Exercise Science, The College of New Jersey, Ewing, New Jersey, USA
| | - Heather Murphy
- Ontario Veterinary College Department of Pathobiology, University of Guelph, Ontario, Canada
| | - David Oryang
- Food and Drug Administration (FDA), US Department of Health and Human Services (DHHS), Center for Food Safety and Applied Nutrition (CFSAN), College Park, United States
| | | | - Emily Pasek
- Department of Earth and Environmental Sciences, Michigan State University, East Lansing, Michigan, USA
| | - Abani K Pradhan
- Department of Nutrition and Food Science & Center for Food Safety and Security Systems, University of Maryland, College Park, Maryland, USA
| | | | - Michael O Ryan
- Department of Civil, Architectural, and Environmental Engineering, Drexel University, Philadelphia, Pennsylvania, USA
| | - Mary Schoen
- Soller Environmental, Berkeley, California, USA
| | - Patrick W M H Smeets
- KWR Water Research Institute, Nieuwegein, The Netherlands
- TU Delft, Delft, The Netherlands
| | | | - Helena Solo-Gabriele
- Department of Chemical, Environmental, and Materials Engineering, College of Engineering, University of Miami, Coral Gables, Florida, USA
| | - Clinton Williams
- US Arid Land Agricultural Research Center, Maricopa, Arizona, USA
| | - Amanda M Wilson
- Community, Environment & Policy Department, Mel and Enid Zuckerman College of Public Health, The University of Arizona, Tucson, Arizona, USA
| | | | - Jumana Alja'fari
- National Institute of Standards and Technology (NIST), Gaithersburg, Maryland, USA
| | - Joan B Rose
- Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan, USA
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Tang L, Rhoads WJ, Eichelberg A, Hamilton KA, Julian TR. Applications of Quantitative Microbial Risk Assessment to Respiratory Pathogens and Implications for Uptake in Policy: A State-of-the-Science Review. ENVIRONMENTAL HEALTH PERSPECTIVES 2024; 132:56001. [PMID: 38728217 PMCID: PMC11086748 DOI: 10.1289/ehp12695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 02/28/2024] [Accepted: 03/08/2024] [Indexed: 05/12/2024]
Abstract
BACKGROUND Respiratory tract infections are major contributors to the global disease burden. Quantitative microbial risk assessment (QMRA) holds potential as a rapidly deployable framework to understand respiratory pathogen transmission and inform policy on infection control. OBJECTIVES The goal of this paper was to evaluate, motivate, and inform further development of the use of QMRA as a rapid tool to understand the transmission of respiratory pathogens and improve the evidence base for infection control policies. METHODS We conducted a literature review to identify peer-reviewed studies of complete QMRA frameworks on aerosol inhalation or contact transmission of respiratory pathogens. From each of the identified studies, we extracted and summarized information on the applied exposure model approaches, dose-response models, and parameter values, including risk characterization. Finally, we reviewed linkages between model outcomes and policy. RESULTS We identified 93 studies conducted in 16 different countries with complete QMRA frameworks for diverse respiratory pathogens, including SARS-CoV-2, Legionella spp., Staphylococcus aureus, influenza, and Bacillus anthracis. Six distinct exposure models were identified across diverse and complex transmission pathways. In 57 studies, exposure model frameworks were informed by their ability to model the efficacy of potential interventions. Among interventions, masking, ventilation, social distancing, and other environmental source controls were commonly assessed. Pathogen concentration, aerosol concentration, and partitioning coefficient were influential exposure parameters as identified by sensitivity analysis. Most (84%, n = 78 ) studies presented policy-relevant content including a) determining disease burden to call for policy intervention, b) determining risk-based threshold values for regulations, c) informing intervention and control strategies, and d) making recommendations and suggestions for QMRA application in policy. CONCLUSIONS We identified needs to further the development of QMRA frameworks for respiratory pathogens that prioritize appropriate aerosol exposure modeling approaches, consider trade-offs between model validity and complexity, and incorporate research that strengthens confidence in QMRA results. https://doi.org/10.1289/EHP12695.
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Affiliation(s)
- Lizhan Tang
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - William J. Rhoads
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Antonia Eichelberg
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Kerry A. Hamilton
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona, USA
- Biodesign Institute Center for Environmental Health Engineering, Arizona State University, Tempe, Arizona, USA
| | - Timothy R. Julian
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
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3
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Clements E, Crank K, Nerenberg R, Atkinson A, Gerrity D, Hannoun D. Quantitative Microbial Risk Assessment Framework Incorporating Water Ages with Legionella pneumophila Growth Rates. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:6540-6551. [PMID: 38574283 PMCID: PMC11025131 DOI: 10.1021/acs.est.4c01208] [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: 02/01/2024] [Revised: 03/20/2024] [Accepted: 03/21/2024] [Indexed: 04/06/2024]
Abstract
Water age in drinking water systems is often used as a proxy for water quality but is rarely used as a direct input in assessing microbial risk. This study directly linked water ages in a premise plumbing system to concentrations of Legionella pneumophila via a growth model. In turn, the L. pneumophila concentrations were used for a quantitative microbial risk assessment to calculate the associated probabilities of infection (Pinf) and clinically severe illness (Pcsi) due to showering. Risk reductions achieved by purging devices, which reduce water age, were also quantified. The median annual Pinf exceeded the commonly used 1 in 10,000 (10-4) risk benchmark in all scenarios, but the median annual Pcsi was always 1-3 orders of magnitude below 10-4. The median annual Pcsi was lower in homes with two occupants (4.7 × 10-7) than with one occupant (7.5 × 10-7) due to more frequent use of water fixtures, which reduced water ages. The median annual Pcsi for homes with one occupant was reduced by 39-43% with scheduled purging 1-2 times per day. Smart purging devices, which purge only after a certain period of nonuse, maintained these lower annual Pcsi values while reducing additional water consumption by 45-62%.
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Affiliation(s)
- Emily Clements
- Southern
Nevada Water Authority, P.O. Box 99954, Las Vegas, Nevada 89193, United States
| | - Katherine Crank
- Southern
Nevada Water Authority, P.O. Box 99954, Las Vegas, Nevada 89193, United States
| | - Robert Nerenberg
- Department
of Civil & Environmental Engineering & Earth Science, University of Notre Dame, 156 Fitzpatrick Hall, Notre
Dame, Indiana 46556, United States
| | - Ariel Atkinson
- Southern
Nevada Water Authority, P.O. Box 99954, Las Vegas, Nevada 89193, United States
| | - Daniel Gerrity
- Southern
Nevada Water Authority, P.O. Box 99954, Las Vegas, Nevada 89193, United States
| | - Deena Hannoun
- Southern
Nevada Water Authority, P.O. Box 99954, Las Vegas, Nevada 89193, United States
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Du X, Ma R, Xiao M, Song W, Tan Y, Wang Z, Ng AHM, Zhang W. Integrated electro-coagulation and gravity driven ceramic membrane bioreactor for roofing rainwater purification: Flux improvement and extreme operating case. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 851:158197. [PMID: 35995152 DOI: 10.1016/j.scitotenv.2022.158197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 08/06/2022] [Accepted: 08/17/2022] [Indexed: 06/15/2023]
Abstract
The collected roofing rainwater with high water quality and large water volume, can alleviate the crisis of water resources and fit the Low-Impact Development (LID) concept. In this work, a novel water purification technology, Electro-Coagulation coupled with Gravity-Driven Ceramic Membrane Bio-Reactor (EC-GDCMBR) was developed for the roofing rainwater purification under long-term operation (136 days). EC-GDCMBR system not only exhibited the better effluent quality, but also obtained the greater flux (~32 LMH). The reason contributed to the high permeability of ceramic membrane and large porosity of biofilm formed by floc growth (~36 μm) during the EC process, which was also proved by SEM image. The coagulation, adsorption, biodegradation, and coprecipitation of EC-GDCMBR was able to synergistically remove the particulate matter, ammonia nitrogen (NH3-N), Total Phosphorus (TP), organic substances, and heavy metal (i.e., Cr, Zn, and Cu). In particular, via the analysis of bacterial abundance, Extracellular Polymeric Substances (EPS), Assimilable Organic Carbon (AOC), Adenosine Tri-Phosphate (ATP) and Confocal Laser Scanning Microscopy (CLSM), EC could sweep most free bacteria on the ceramic membrane surface, enhancing the biological purification efficiency. Furthermore, a large amount of Pseudomonas (12.4 %-66.7 %) and Nitrospira (1.46 %-3.16 %) in the aggregates formed the biofilms, improved the NH3-N removal. During the long-term operation, there are some unavoidable problems, such as the thick and ripened biofilm of EC-GDCMBR would crack and fall off. Based on this, the current work also studied the reliability of GDCMBR under "extreme operating case", and the results showed that neither the biofilm detachment nor the biofilm breakup had a significant impact on the effluent quality. Overall, the findings of this study suggest the reliability of EC-GDCMBR for the sustainable operation of roofing rainwater purification and improve the application value of decentralized rainwater harvest device.
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Affiliation(s)
- Xing Du
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Rong Ma
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Mengyao Xiao
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Wei Song
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Yingshi Tan
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Zhihong Wang
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Alex Hay-Man Ng
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, PR China; School of Civil and Environmental Engineering, University of New South Wales, Sydney 2052, Australia; Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, Guangdong University of Technology, Guangzhou 510006, PR China.
| | - Wenxiang Zhang
- Biological and Environmental Science and Engineering Division, Water Desalination and Reuse Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
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5
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Shen Y, Haig SJ, Prussin AJ, LiPuma JJ, Marr LC, Raskin L. Shower water contributes viable nontuberculous mycobacteria to indoor air. PNAS NEXUS 2022; 1:pgac145. [PMID: 36712351 PMCID: PMC9802317 DOI: 10.1093/pnasnexus/pgac145] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 11/07/2022] [Indexed: 11/11/2022]
Abstract
Nontuberculous mycobacteria (NTM) are frequently present in municipal drinking water and building plumbing, and some are believed to cause respiratory tract infections through inhalation of NTM-containing aerosols generated during showering. However, the present understanding of NTM transfer from water to air is insufficient to develop NTM risk mitigation strategies. This study aimed to characterize the contribution of shower water to the abundance of viable NTM in indoor air. Shower water and indoor air samples were collected, and 16S rRNA and rpoB genes were sequenced. The sequencing results showed that running the shower impacted the bacterial community structure and NTM species composition in indoor air by transferring certain bacteria from water to air. A mass balance model combined with NTM quantification results revealed that on average 1/132 and 1/254 of NTM cells in water were transferred to air during 1 hour of showering using a rain and massage showerhead, respectively. A large fraction of the bacteria transferred from water to air were membrane-damaged, i.e. they had compromised membranes based on analysis by live/dead staining and flow cytometry. However, the damaged NTM in air were recoverable as shown by growth in a culture medium mimicking the respiratory secretions of people with cystic fibrosis, implying a potential infection risk by NTM introduced to indoor air during shower running. Among the recovered NTM, Mycobacterium mucogenicum was the dominant species as determined by rpoB gene sequencing. Overall, this study lays the groundwork for future pathogen risk management and public health protection in the built environment.
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Affiliation(s)
| | | | - Aaron J Prussin
- Department of Civil and Environmental Engineering, Virginia Tech, 418 Durham Hall, Blacksburg, VA 24061, USA
| | - John J LiPuma
- Department of Pediatrics, University of Michigan Medical School, 1500 E. Medical Center Dr., Ann Arbor, MI 48109, USA
| | - Linsey C Marr
- Department of Civil and Environmental Engineering, Virginia Tech, 418 Durham Hall, Blacksburg, VA 24061, USA
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Ishaq S, Sadiq R, Chhipi-Shrestha G, Farooq S, Hewage K. Developing an Integrated "Regression-QMRA method" to Predict Public Health Risks of Low Impact Developments (LIDs) for Improved Planning. ENVIRONMENTAL MANAGEMENT 2022; 70:633-649. [PMID: 35543727 DOI: 10.1007/s00267-022-01657-0] [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: 11/19/2021] [Accepted: 04/25/2022] [Indexed: 06/14/2023]
Abstract
Worldwide Low Impact Developments (LIDs) are used for sustainable stormwater management; however, both the stormwater and LIDs carry microbial pathogens. The widespread development of LIDs is likely to increase human exposure to pathogens and risk of infection, leading to unexpected disease outbreaks in urban communities. The risk of infection from exposure to LIDs has been assessed via Quantitative Microbial Risk Assessment (QMRA) during the operation of these infrastructures; no effort is made to evaluate these risks during the planning phase of LID treatment train in urban communities. We developed a new integrated "Regression-QMRA method" by examining the relationship between pathogens' concentration and environmental variables. Applying of this methodology to a planned LID train shows that the predicted disease burden of diarrhea from Campylobacter is highest (i.e. 16.902 DALYs/1000 persons/yr) during landscape irrigation and playing on the LID train, followed by Giardia, Cryptosporidium, and Norovirus. These results illustrate that the risk of microbial infection can be predicted during the planning phase of LID treatment train. These predictions are of great value to municipalities and decision-makers to make informed decisions and ensure risk-based planning of stormwater systems before their development.
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Affiliation(s)
- Sadia Ishaq
- School of Engineering, University of British Columbia, Okanagan Campus, Kelowna, BC, V1V 1V7, Canada
| | - Rehan Sadiq
- School of Engineering, University of British Columbia, Okanagan Campus, Kelowna, BC, V1V 1V7, Canada.
| | - Gyan Chhipi-Shrestha
- School of Engineering, University of British Columbia, Okanagan Campus, Kelowna, BC, V1V 1V7, Canada
| | - Shaukat Farooq
- King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, 31261, Saudi Arabia
| | - Kasun Hewage
- School of Engineering, University of British Columbia, Okanagan Campus, Kelowna, BC, V1V 1V7, Canada
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Proctor C, Garner E, Hamilton KA, Ashbolt NJ, Caverly LJ, Falkinham JO, Haas CN, Prevost M, Prevots DR, Pruden A, Raskin L, Stout J, Haig SJ. Tenets of a holistic approach to drinking water-associated pathogen research, management, and communication. WATER RESEARCH 2022; 211:117997. [PMID: 34999316 PMCID: PMC8821414 DOI: 10.1016/j.watres.2021.117997] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 12/13/2021] [Accepted: 12/19/2021] [Indexed: 05/10/2023]
Abstract
In recent years, drinking water-associated pathogens that can cause infections in immunocompromised or otherwise susceptible individuals (henceforth referred to as DWPI), sometimes referred to as opportunistic pathogens or opportunistic premise plumbing pathogens, have received considerable attention. DWPI research has largely been conducted by experts focusing on specific microorganisms or within silos of expertise. The resulting mitigation approaches optimized for a single microorganism may have unintended consequences and trade-offs for other DWPI or other interests (e.g., energy costs and conservation). For example, the ecological and epidemiological issues characteristic of Legionella pneumophila diverge from those relevant for Mycobacterium avium and other nontuberculous mycobacteria. Recent advances in understanding DWPI as part of a complex microbial ecosystem inhabiting drinking water systems continues to reveal additional challenges: namely, how can all microorganisms of concern be managed simultaneously? In order to protect public health, we must take a more holistic approach in all aspects of the field, including basic research, monitoring methods, risk-based mitigation techniques, and policy. A holistic approach will (i) target multiple microorganisms simultaneously, (ii) involve experts across several disciplines, and (iii) communicate results across disciplines and more broadly, proactively addressing source water-to-customer system management.
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Affiliation(s)
- Caitlin Proctor
- Department of Agricultural and Biological Engineering, Division of Environmental and Ecological Engineering, Purdue University, West Lafayette, IN, USA
| | - Emily Garner
- Wadsworth Department of Civil & Environmental Engineering, West Virginia University, Morgantown, WV, USA
| | - Kerry A Hamilton
- School of Sustainable Engineering and the Built Environment and The Biodesign Centre for Environmental Health Engineering, Arizona State University, Tempe, AZ, USA
| | - Nicholas J Ashbolt
- Faculty of Science and Engineering, Southern Cross University, Gold Coast. Queensland, Australia
| | - Lindsay J Caverly
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - Charles N Haas
- Department of Civil, Architectural & Environmental Engineering, Drexel University, Philadelphia, PA, USA
| | - Michele Prevost
- Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, Montreal, Quebec, Canada
| | - D Rebecca Prevots
- Epidemiology Unit, Laboratory of Clinical Immunology and Microbiology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Amy Pruden
- Department of Civil & Environmental Engineering, Virginia Tech, Blacksburg, VA USA
| | - Lutgarde Raskin
- Department of Civil & Environmental Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Janet Stout
- Department of Civil & Environmental Engineering, University of Pittsburgh, and Special Pathogens Laboratory, Pittsburgh, PA, USA
| | - Sarah-Jane Haig
- Department of Civil & Environmental Engineering, and Department of Environmental & Occupational Health, University of Pittsburgh, Pittsburgh, PA, USA.
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8
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Practitioners’ Perspective on the Prevalent Water Quality Management Practices for Legionella Control in Large Buildings in the United States. WATER 2022. [DOI: 10.3390/w14040663] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Managing building water systems is complicated by the need to maintain hot water temperatures high enough to control the growth of Legionella spp. while minimizing the risk of scalding. This study assessed water quality management practices in large buildings in the United States. Surveys conducted with building water quality managers found that more than 85% of buildings have hot water temperatures that are consistent with scald risk mitigation guidelines (i.e., <122 °F/50 °C). However, nearly two thirds and three quarters of buildings do not comply with the common temperature guidance for opportunistic pathogen control, i.e., water heater setpoint > 140 °F (60 °C) and recirculation loop > 122 °F (50 °C), respectively; median values for both setpoint and recirculation loop temperatures are 10 °F (6 °C) or more below temperatures recommended for opportunistic pathogen control. These observations suggest that many buildings are prone to Legionella spp. risk. The study also found that 27% of buildings do not comply with guidelines for time to equilibrium hot water temperature, over 33% fail to monitor temperature in the recirculation loop, more than 70% fail to replace or disinfect showerheads, more than 40% lack a written management plan, and only a minority conduct any monitoring of residual disinfectant levels or microbiological quality. Given the rise in Legionellosis infections in recent years, coupled with highlighted water quality concerns because of prolonged water stagnation in plumbing, such as in buildings closed due to COVID-19, current management practices, which appear to be focused on scald risk, may need to be broadened to include greater attention to control of opportunistic pathogens. To accomplish this, there is a need for formal training and resources for facility managers.
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9
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Zhang X, Xia S, Ye Y, Wang H. Opportunistic pathogens exhibit distinct growth dynamics in rainwater and tap water storage systems. WATER RESEARCH 2021; 204:117581. [PMID: 34461496 DOI: 10.1016/j.watres.2021.117581] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 07/09/2021] [Accepted: 08/16/2021] [Indexed: 06/13/2023]
Abstract
Opportunistic pathogens (OPs) are emerging microbial contaminants in engineered water systems, yet their growth potential in rainwater systems has not been evaluated. The purpose of this study was to compare the growth dynamics of bacterial OPs and related genera (Pseudomonas aeruginosa, Legionella spp., L. pneumophila, Mycobacterium spp., and M. avium), two amoebal hosts (Acanthamoeba spp. and Vermamoeba vermiformis), and the fecal indicator Escherichia coli in simulated rainwater and tap water storage systems (SWSSs). Quantitative polymerase chain reaction (q-PCR) analysis of target microorganisms in SWSS influents and effluents demonstrated that P. aeruginosa and Legionella thrived in rainwater, but not in tap water. V. vermiformis proliferated in both rainwater and tap water polyvinyl chloride (PVC) SWSSs, while mycobacteria were largely absent in rainwater SWSSs. Tank materials exerted stronger influence on target microorganisms in rainwater SWSSs relative to tap water SWSSs, with species-specific responses noted in bulk water and biofilm. For instance, P. aeruginosa and V. vermiformis had the highest gene copy numbers in PVC rainwater SWSS effluents and biofilm, while Legionella peaked in stainless steel rainwater SWSS effluents and PVC rainwater SWSS biofilm. These results highlighted the OP contamination risks in rainwater storage systems and provided insights into rainwater system design and operation in terms of OP control.
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Affiliation(s)
- Xiaodong Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Chengtou Water Group Corporation, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Siqing Xia
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
| | - Yinyin Ye
- Department of Civil, Structural and Environmental Engineering, University at Buffalo, Buffalo, New York 14260, USA
| | - Hong Wang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
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Denissen JK, Reyneke B, Waso M, Khan S, Khan W. Human Pathogenic Bacteria Detected in Rainwater: Risk Assessment and Correlation to Microbial Source Tracking Markers and Traditional Indicators. Front Microbiol 2021; 12:659784. [PMID: 34025613 PMCID: PMC8138566 DOI: 10.3389/fmicb.2021.659784] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 04/09/2021] [Indexed: 11/22/2022] Open
Abstract
Roof-harvested rainwater (RHRW) was investigated for the presence of the human pathogenic bacteria Mycobacterium tuberculosis (M. tuberculosis), Yersinia spp. and Listeria monocytogenes (L. monocytogenes). While Yersinia spp. were detected in 92% (n = 25) of the RHRW samples, and L. monocytogenes and M. tuberculosis were detected in 100% (n = 25) of the samples, a significantly higher mean concentration (1.4 × 103 cells/100 mL) was recorded for L. monocytogenes over the sampling period. As the identification of appropriate water quality indicators is crucial to ensure access to safe water sources, correlation of the pathogens to traditional indicator organisms [Escherichia coli (E. coli) and Enterococcus spp.] and microbial source tracking (MST) markers (Bacteroides HF183, adenovirus and Lachnospiraceae) was conducted. A significant positive correlation was then recorded for E. coli versus L. monocytogenes (r = 0.6738; p = 0.000), and Enterococcus spp. versus the Bacteroides HF183 marker (r = 0.4071; p = 0.043), while a significant negative correlation was observed for M. tuberculosis versus the Bacteroides HF183 marker (r = −0.4558; p = 0.022). Quantitative microbial risk assessment indicated that the mean annual risk of infection posed by L. monocytogenes in the RHRW samples exceeded the annual infection risk benchmark limit (1 × 10–4 infections per person per year) for intentional drinking (∼10–4). In comparison, the mean annual risk of infection posed by E. coli was exceeded for intentional drinking (∼10–1), accidental consumption (∼10–3) and cleaning of the home (∼10–3). However, while the risk posed by M. tuberculosis for the two relevant exposure scenarios [garden hosing (∼10–5) and washing laundry by hand (∼10–5)] was below the benchmark limit, the risk posed by adenovirus for garden hosing (∼10–3) and washing laundry by hand (∼10–3) exceeded the benchmark limit. Thus, while the correlation analysis confirms that traditional indicators and MST markers should be used in combination to accurately monitor the pathogen-associated risk linked to the utilisation of RHRW, the integration of QMRA offers a more site-specific approach to monitor and estimate the human health risks associated with the use of RHRW.
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Affiliation(s)
- Julia K Denissen
- Department of Microbiology, Faculty of Science, Stellenbosch University, Stellenbosch, South Africa
| | - Brandon Reyneke
- Department of Microbiology, Faculty of Science, Stellenbosch University, Stellenbosch, South Africa
| | - Monique Waso
- Faculty of Health Sciences, University of Johannesburg, Doornfontein, South Africa
| | - Sehaam Khan
- Faculty of Health Sciences, University of Johannesburg, Doornfontein, South Africa
| | - Wesaal Khan
- Department of Microbiology, Faculty of Science, Stellenbosch University, Stellenbosch, South Africa
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11
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Kusumawardhana A, Zlatanovic L, Bosch A, van der Hoek JP. Microbiological Health Risk Assessment of Water Conservation Strategies: A Case Study in Amsterdam. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:2595. [PMID: 33807661 PMCID: PMC7967349 DOI: 10.3390/ijerph18052595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 02/24/2021] [Accepted: 03/03/2021] [Indexed: 11/24/2022]
Abstract
The aim of this study was to assess the health risks that may arise from the implementation of greywater reuse and rainwater harvesting for household use, especially for toilet flushing. In addition, the risk of cross connections between these systems and the drinking water system was considered. Quantitative microbial risk assessment (QMRA) is a method that uses mathematical modelling to estimate the risk of infection when exposure to pathogens happens and was used in this study to assess the health risks. The results showed that using rainwater without prior treatment for toilet flushing poses an annual infection risk from L. pneumophila at 0.64 per-person-per-year (pppy) which exceeds the Dutch standard of 10-4 pppy. The use of untreated greywater showed a risk that is below the standard. However, treatment is recommended due to the ability of P. aeruginosa to grow in the reuse system. Moreover, showering and drinking with cross-connected water has a high annual infection risk that exceeds the standard due to contact with Staphylococcus aureus and E. coli O157:H7. Several measures can be implemented to mitigate the risks such as treating the greywater and rainwater with a minimum of 5-log removal, closing the toilet lid while flushing, good design of greywater and rainwater collection systems, and rigorous plumbing installation procedures.
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Affiliation(s)
- Agung Kusumawardhana
- Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5, 2600 AA Delft, The Netherlands; (A.K.); (L.Z.)
| | - Ljiljana Zlatanovic
- Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5, 2600 AA Delft, The Netherlands; (A.K.); (L.Z.)
- Amsterdam Institute for Advanced Metropolitan Solutions, Kattenburgerstraat 5, 1018 JA Amsterdam, The Netherlands
- Water Supply Company Noord-Holland PWN, Rijksweg 501, 1991 AS Velserbroek, The Netherlands
| | - Arne Bosch
- Waternet, P.O. Box 94370, 1090 GJ Amsterdam, The Netherlands;
| | - Jan Peter van der Hoek
- Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5, 2600 AA Delft, The Netherlands; (A.K.); (L.Z.)
- Amsterdam Institute for Advanced Metropolitan Solutions, Kattenburgerstraat 5, 1018 JA Amsterdam, The Netherlands
- Waternet, P.O. Box 94370, 1090 GJ Amsterdam, The Netherlands;
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12
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Hozalski RM, LaPara TM, Zhao X, Kim T, Waak MB, Burch T, McCarty M. Flushing of Stagnant Premise Water Systems after the COVID-19 Shutdown Can Reduce Infection Risk by Legionella and Mycobacterium spp. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:15914-15924. [PMID: 33232602 DOI: 10.1021/acs.est.0c06357] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
There is concern about potential exposure to opportunistic pathogens when reopening buildings closed due to the COVID-19 pandemic. In this study, water samples were collected before, during, and after flushing showers in five unoccupied (i.e., for ∼2 months) university buildings with quantification of opportunists via a cultivation-based assay (Legionella pneumophila only) and quantitative PCR. L. pneumophila were not detected by either method; Legionella spp., nontuberculous mycobacteria (NTM), and Mycobacterium avium complex (MAC), however, were widespread. Using quantitative microbial risk assessment (QMRA), the estimated risks of illness from exposure to L. pneumophila and MAC via showering were generally low (i.e., less than a 10-7 daily risk threshold), with the exception of systemic infection risk from MAC exposure in some buildings. Flushing rapidly restored the total chlorine (as chloramine) residual and decreased bacterial gene targets to building inlet concentrations within 30 min. During the postflush stagnation period, the residual chlorine dissipated within a few days and bacteria rebounded, approaching preflush concentrations after 6-7 days. These results suggest that flushing can quickly improve water quality in unoccupied buildings, but the improvement may only last a few days.
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Affiliation(s)
- Raymond M Hozalski
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis 55455, Minnesota, United States
| | - Timothy M LaPara
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis 55455, Minnesota, United States
| | - Xiaotian Zhao
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis 55455, Minnesota, United States
| | - Taegyu Kim
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis 55455, Minnesota, United States
| | - Michael B Waak
- Norwegian University of Science and Technology, Trondheim 7031, Norway
- Department of Infrastructure, SINTEF Community, Trondheim 7031, Norway
| | - Tucker Burch
- Agricultural Research Service, U.S. Department of Agriculture, Marshfield, Wisconsin 54449, United States
| | - Michael McCarty
- School of Public Health, University of Minnesota, Minneapolis 55455, Minnesota, United States
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13
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Reyneke B, Hamilton KA, Fernández-Ibáñez P, Polo-López MI, McGuigan KG, Khan S, Khan W. EMA-amplicon-based sequencing informs risk assessment analysis of water treatment systems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 743:140717. [PMID: 32679496 DOI: 10.1016/j.scitotenv.2020.140717] [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: 03/25/2020] [Revised: 06/29/2020] [Accepted: 07/01/2020] [Indexed: 06/11/2023]
Abstract
Illumina amplicon-based sequencing was coupled with ethidium monoazide bromide (EMA) pre-treatment to monitor the total viable bacterial community and subsequently identify and prioritise the target organisms for the health risk assessment of the untreated rainwater and rainwater treated using large-volume batch solar reactor prototypes installed in an informal settlement and rural farming community. Taxonomic assignments indicated that Legionella and Pseudomonas were the most frequently detected genera containing opportunistic bacterial pathogens in the untreated and treated rainwater at both sites. Additionally, Mycobacterium, Clostridium sensu stricto and Escherichia/Shigella displayed high (≥80%) detection frequencies in the untreated and/or treated rainwater samples at one or both sites. Numerous exposure scenarios (e.g. drinking, cleaning) were subsequently investigated and the health risk of using untreated and solar reactor treated rainwater in developing countries was quantified based on the presence of L. pneumophila, P. aeruginosa and E. coli. The solar reactor prototypes were able to reduce the health risk associated with E. coli and P. aeruginosa to below the 1 × 10-4 annual benchmark limit for all the non-potable uses of rainwater within the target communities (exception of showering for E. coli). However, the risk associated with intentional drinking of untreated or treated rainwater exceeded the benchmark limit (E. coli and P. aeruginosa). Additionally, while the solar reactor treatment reduced the risk associated with garden hosing and showering based on the presence of L. pneumophila, the risk estimates for both activities still exceeded the annual benchmark limit. The large-volume batch solar reactor prototypes were thus able to reduce the risk posed by the target bacteria for non-potable activities rainwater is commonly used for in water scarce regions of sub-Saharan Africa. This study highlights the need to assess water treatment systems in field trials using QMRA.
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Affiliation(s)
- B Reyneke
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa
| | - K A Hamilton
- School for Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ 85281, United States; The Biodesign Institute Center for Environmental Health Engineering, Arizona State University, Tempe, AZ 85281, United States
| | - P Fernández-Ibáñez
- Plataforma Solar de Almeria-CIEMAT, P.O. Box 22, Tabernas, Almería, Spain; Nanotechnology and Integrated BioEngineering Centre, School of Engineering, University of Ulster, Newtownabbey, Northern Ireland, United Kingdom
| | - M I Polo-López
- Plataforma Solar de Almeria-CIEMAT, P.O. Box 22, Tabernas, Almería, Spain
| | - K G McGuigan
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - S Khan
- Faculty of Health Sciences, University of Johannesburg, PO Box 17011, Doornfontein 2028, South Africa
| | - W Khan
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa.
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14
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Jamal R, Mubarak S, Sahulka SQ, Kori JA, Tajammul A, Ahmed J, Mahar RB, Olsen MS, Goel R, Weidhaas J. Informing water distribution line rehabilitation through quantitative microbial risk assessment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 739:140021. [PMID: 32758946 DOI: 10.1016/j.scitotenv.2020.140021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/01/2020] [Accepted: 06/04/2020] [Indexed: 06/11/2023]
Abstract
Poor urban water quality has been linked to diminished source water quality, poorly functioning water treatment systems and infiltration into distribution lines after treatment resulting in microbiological contamination. With limited funding to rehabilitate distribution lines, developing nations need tools to identify the areas of greatest concern to human health so as to target cost effective remediation approaches. Herein, a case study of Hyderabad, Pakistan was used to demonstrate the efficacy of combining quantitative microbial risk assessment (QMRA) for multiple pathogens with spatial distribution system modeling to identify areas for pipe rehabilitation. Abundance of Escherichia coli, Enterococcus (enterococci), Salmonella spp., Shigella spp., Giardia intestinalis, Vibrio cholera, norovirus GI and adenovirus 40/41, were determined in 85 locations including the source water, treatment plant effluent and the city distribution lines. Bayesian statistics and Monte Carlo simulations were used in the QMRA to account for left-censored microbial abundance distributions. Bacterial and viral abundances in the distribution system samples decreased as follows: 9400 ± 19,800 norovirus gene copies/100 mL (average ± standard deviation, 100% of samples positive); 340 ± 2200 enterococci CFU/100 mL (94%), 71 ± 97 Shigella sp. CFU/100 mL (97%), 60 ± 360 E. coli CFU/100 mL (89%), 35 ± 79 adenovirus gene copies/100 mL (100%), and 21 ± 46 Salmonella sp. CFU/100 mL (76%). The QMRA revealed unacceptable probabilities of illness (>1 in 10,000 illness level) from the four exposure routes considered (drinking water, or only showering, tooth brushing, and rinsing vegetables consumed raw). Disease severity indices based on the QMRA combined with mapping the distribution system revealed areas for targeted rehabilitation. The combined intensive sampling, risk assessment and mapping can be used in low- and middle-income countries to target distribution system rehabilitation efforts and improve health outcomes.
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Affiliation(s)
- Rubayat Jamal
- Civil and Environmental Engineering, University of Utah, 110 Central Campus Drive Suite 2000, Salt Lake City, UT 84112, USA
| | - Shaista Mubarak
- US Pakistan Center for Advanced Studies in Water, Mehran University of Engineering and Technology, Jamshoro, 76062, Sindh, Pakistan
| | - Sierra Q Sahulka
- Civil and Environmental Engineering, University of Utah, 110 Central Campus Drive Suite 2000, Salt Lake City, UT 84112, USA
| | - Junaid A Kori
- US Pakistan Center for Advanced Studies in Water, Mehran University of Engineering and Technology, Jamshoro, 76062, Sindh, Pakistan
| | - Ayesha Tajammul
- US Pakistan Center for Advanced Studies in Water, Mehran University of Engineering and Technology, Jamshoro, 76062, Sindh, Pakistan
| | - Jamil Ahmed
- US Pakistan Center for Advanced Studies in Water, Mehran University of Engineering and Technology, Jamshoro, 76062, Sindh, Pakistan
| | - Rasool B Mahar
- US Pakistan Center for Advanced Studies in Water, Mehran University of Engineering and Technology, Jamshoro, 76062, Sindh, Pakistan
| | | | - Ramesh Goel
- Civil and Environmental Engineering, University of Utah, 110 Central Campus Drive Suite 2000, Salt Lake City, UT 84112, USA
| | - Jennifer Weidhaas
- Civil and Environmental Engineering, University of Utah, 110 Central Campus Drive Suite 2000, Salt Lake City, UT 84112, USA.
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15
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Xue J, Zhang B, Lamori J, Shah K, Zabaleta J, Garai J, Taylor CM, Sherchan SP. Molecular detection of opportunistic pathogens and insights into microbial diversity in private well water and premise plumbing. JOURNAL OF WATER AND HEALTH 2020; 18:820-834. [PMID: 33095203 PMCID: PMC9115838 DOI: 10.2166/wh.2020.271] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Private well water systems in rural areas that are improperly maintained will result in poor drinking water quality, loss of water supply, and pose human health risk. The purpose of this study was to investigate the occurrence of fecal indicator bacteria (FIB) and opportunistic pathogens in private well water in rural areas surrounding New Orleans, Louisiana. Our results confirmed the ubiquitous nature of Legionella (86.7%) and mycobacteria (68.1%) in private well water in the study area, with gene concentration ranged from 0.60 to 5.53 and 0.67 to 5.95 Log10 of GC/100 mL, respectively. Naegleria fowleri target sequence was detected in 16.8% and Escherichia coli was detected in 43.4% of the water samples. Total coliform, as well as Legionella and mycobacteria genetic markers' concentrations were significantly reduced by 3-minute flushing. Next-generation sequencing (NGS) data indicated that the abundance of bacterial species was significantly increased in water collected in kitchens compared with samples from wells directly. This study provided integrated knowledge on the persistence of pathogenic organisms in private well water. Further study is needed to explore the presence of clinical species of those opportunistic pathogens in private well water systems to elucidate the health risk.
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Affiliation(s)
- Jia Xue
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, 70112, USA E-mail:
| | - Bowen Zhang
- Department of Natural Resources and Environmental Management, Ball State University, Muncie, Indiana, 47306, USA
| | - Jennifer Lamori
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, 70112, USA E-mail:
| | - Kinjal Shah
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, 70112, USA E-mail:
| | - Jovanny Zabaleta
- Department of Pediatrics and Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center, New Orleans, Louisiana, 70112, USA
| | - Jone Garai
- Department of Pediatrics and Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center, New Orleans, Louisiana, 70112, USA
| | - Christopher M Taylor
- Department of Microbiology, Immunology & Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, 70112, USA
| | - Samendra P Sherchan
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, 70112, USA E-mail:
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16
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Ley CJ, Proctor CR, Jordan K, Ra K, Noh Y, Odimayomi T, Julien R, Kropp I, Mitchell J, Nejadhashemi AP, Whelton AJ, Aw TG. Impacts of Municipal Water-Rainwater Source Transitions on Microbial and Chemical Water Quality Dynamics at the Tap. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:11453-11463. [PMID: 32786341 DOI: 10.1021/acs.est.0c03641] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
When rainwater harvesting is utilized as an alternative water resource in buildings, a combination of municipal water and rainwater is typically required to meet water demands. Altering source water chemistry can disrupt pipe scale and biofilm and negatively impact water quality at the distribution level. Still, it is unknown if similar reactions occur within building plumbing following a transition in source water quality. The goal of this study was to investigate changes in water chemistry and microbiology at a green building following a transition between municipal water and rainwater. We monitored water chemistry (metals, alkalinity, and disinfectant byproducts) and microbiology (total cell counts, plate counts, and opportunistic pathogen gene markers) throughout two source water transitions. Several constituents including alkalinity and disinfectant byproducts served as indicators of municipal water remaining in the system since the rainwater source does not contain these constituents. In the treated rainwater, microbial proliferation and Legionella spp. gene copy numbers were often three logs higher than those in municipal water. Because of differences in source water chemistry, rainwater and municipal water uniquely interacted with building plumbing and generated distinctively different drinking water chemical and microbial quality profiles.
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Affiliation(s)
- Christian J Ley
- Environmental and Ecological Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Caitlin R Proctor
- Environmental and Ecological Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Lyles School of Civil Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Kathryn Jordan
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, 1440 Canal Street, Suite 2100, New Orleans, Louisiana 70112, United States
| | - Kyungyeon Ra
- Lyles School of Civil Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Yoorae Noh
- Lyles School of Civil Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Tolulope Odimayomi
- Environmental and Ecological Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Ryan Julien
- Department of Biosystems Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - Ian Kropp
- Department of Biosystems Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - Jade Mitchell
- Department of Biosystems Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - A Pouyan Nejadhashemi
- Department of Biosystems Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - Andrew J Whelton
- Environmental and Ecological Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Lyles School of Civil Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Tiong Gim Aw
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, 1440 Canal Street, Suite 2100, New Orleans, Louisiana 70112, United States
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17
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Huang C, Shen Y, Smith RL, Dong S, Nguyen TH. Effect of disinfectant residuals on infection risks from Legionella pneumophila released by biofilms grown under simulated premise plumbing conditions. ENVIRONMENT INTERNATIONAL 2020; 137:105561. [PMID: 32088542 DOI: 10.1016/j.envint.2020.105561] [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: 07/04/2019] [Revised: 02/05/2020] [Accepted: 02/06/2020] [Indexed: 06/10/2023]
Abstract
The ubiquitous presence of biofilms in premise plumbing and stagnation, which commonly occurs in premise plumbing, can exacerbate the decay of chlorine residual in drinking water. Using biofilms grown in a simulated premise plumbing setup fed directly with freshly treated water at two full-scale water treatment plants, we previously determined the mass transfer coefficients for chlorine decay in premise plumbing. These coefficients coupled with inactivation kinetics of L. pneumophila released from biofilms reported previously were integrated into a Monte Carlo framework to estimate the infection risk of biofilm-derived L. pneumophila from 1 to 48 h of stagnation. The annual infection risk was significantly higher when water stayed stagnant for up to 48 h in pipes covered internally with biofilms, compared to clean pipes without biofilms. The decay of residual chlorine due to biofilms during 48-hour stagnation led to up to 6 times increase in the annual infection risk compared to the case where biofilms was absent. Global sensitivity analysis revealed that the rate of L. pneumophila detachment from biofilms and the decay of chlorine residual during stagnation are the two most important factors influencing the infection risks. Stagnation caused by water use patterns and water-saving devices in the premise plumbing can lead to increased infection risk by biofilm-derived L. pneumophila. Overall, this study's findings suggested that biofilms could induce chlorine decay and consequently increase L. pneumophila infection risk. Thus, reducing stagnation, maintaining residual chlorine, and suppressing biofilm growth could contribute to better management of L. pneumophila infection risk.
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Affiliation(s)
- Conghui Huang
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Yun Shen
- Department of Chemical and Environmental Engineering, The University of California, Riverside, Riverside, CA 92521, United States
| | - Rebecca L Smith
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Shengkun Dong
- Guangdong Engineering Technology Research Center of Water Security Regulation and Control for Southern China, Key Laboratory of Water Cycle and Water Security in Southern China of Guangdong Higher Education Institute, School of Civil Engineering, Sun Yat-sen University, Guangzhou, Guangdong 510275, China.
| | - Thanh H Nguyen
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
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Abstract
Burden of disease analyses can quantify the relative impact of different exposures on population health outcomes. Gastroenteritis where the causative pathogen was not determined and respiratory illness resulting from exposure to opportunistic pathogens transmitted by water aerosols have not always been considered in waterborne burden of disease estimates. We estimated the disease burden attributable to nine enteric pathogens, unspecified pathogens leading to gastroenteritis, and three opportunistic pathogens leading primarily to respiratory illness, in Ontario, Canada (population ~14 million). Employing a burden of disease framework, we attributed a fraction of annual (year 2016) emergency department (ED) visits, hospitalisations and deaths to waterborne transmission. Attributable fractions were developed from the literature and clinical input, and unattributed disease counts were obtained using administrative data. Our Monte Carlo simulation reflected uncertainty in the inputs. The estimated mean annual attributable rates for waterborne diseases were (per 100 000 population): 69 ED visits, 12 hospitalisations and 0.52 deaths. The corresponding 5th–95th percentile estimates were (per 100 000 population): 13–158 ED visits, 5–22 hospitalisations and 0.29–0.83 deaths. The burden of disease due to unspecified pathogens dominated these rates: 99% for ED visits, 63% for hospitalisations and 40% for deaths. However, when a causative pathogen was specified, the majority of hospitalisations (83%) and deaths (97%) resulted from exposure to the opportunistic pathogens Legionella spp., non-tuberculous mycobacteria and Pseudomonas spp. The waterborne disease burden in Ontario indicates the importance of gastroenteritis not traced back to a particular pathogen and of opportunistic pathogens transmitted primarily through contact with water aerosols.
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19
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Zhang X, Xia S, Zhao R, Wang H. Effect of temperature on opportunistic pathogen gene markers and microbial communities in long-term stored roof-harvested rainwater. ENVIRONMENTAL RESEARCH 2020; 181:108917. [PMID: 31759642 DOI: 10.1016/j.envres.2019.108917] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 11/07/2019] [Accepted: 11/10/2019] [Indexed: 06/10/2023]
Abstract
Roof-harvested rainwater (RHRW) has received increasing attention in recent years as an alternative water source for domestic use, yet its biological stability during storage is not fully understood. This study investigated the effects of temperature (4 °C, 20 °C and 30 °C) on the microbiological characteristics of RHRW over a storage period of 60 days by targeting different microbial groups including total bacteria and fecal indictor Escherichia coli, bacterial opportunistic pathogen genera and species (Legionella spp, Legionella pneumophila, Mycobacterium spp, Mycobacterium avium, Pseudomonas aeruginosa), and two amoebas (Acanthamoeba and Vermamoeba vermiformis). The rainwater chemistry demonstrated no obvious change during storage. The highest biomass was observed in RHRW stored at 30 °C, as measured by heterotrophic bacterial counts, adenosine triphosphate, and 16S rRNA gene numbers. Gene markers of E. coli, Legionella spp., P. aeruginosa, and V. vermiformis were detected in fresh RHRW and can persist during RHRW storage; whereas P. aeruginosa was the only species demonstrated significant regrowth at higher storage temperatures (P < 0.05). Acanthamoeba spp. was only detected in RHRW after 50 days of storage at three investigated temperatures, highlighting increased health risks in long-term stored RHRW. Bacterial community compositions were significantly different in RHRW stored at different temperatures, with increased variations among triplicate storage bottles noted at higher temperatures along with storage time. The results provide insights into RHRW storage practices in terms of mitigating microbial contamination risks.
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Affiliation(s)
- Xiaodong Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Siqing Xia
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Renzun Zhao
- Civil, Architectural and Environmental Engineering Department, North Carolina Agricultural and Technical State University, Greensboro, NC 27411, USA
| | - Hong Wang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
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Ma Y, Deilami K, Egodawatta P, Liu A, McGree J, Goonetilleke A. Creating a hierarchy of hazard control for urban stormwater management. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 255:113217. [PMID: 31541818 DOI: 10.1016/j.envpol.2019.113217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 09/06/2019] [Accepted: 09/07/2019] [Indexed: 06/10/2023]
Abstract
Urban stormwater reuse is becoming increasingly prevalent to overcome the serious urban water scarcity being experienced around the world. Therefore, the adoption of reliable approaches to minimise the human health risk posed by pollutants commonly present in urban stormwater such as heavy metals and polycyclic aromatic hydrocarbons (PAHs) is critical for safe stormwater reuse. This study collected a total of 40 pollutant build-up samples and analysed the concentrations of nine heavy metals and 15 PAH species. Based on pollutant build-up data, pollutant concentrations in stormwater were estimated through modelling. Risk assessment was conducted using an existing model developed by previous studies. The study outcomes confirmed that simply evaluating the individual pollutant concentrations based on guideline threshold values cannot comprehensively estimate the overall human health risk posed by these pollutants. Accordingly, it is recommended that the assessment of the overall human health risk should be based on the pollutant mix present as provided by the models discussed in this paper. The study also demonstrated the practical application of a robust risk assessment model to derive the hierarchy of hazard control to provide a reliable underpinning to urban stormwater risk management. The outcomes suggest that decentralised hazard control methods such as the provision of custom designed Water Sensitive Urban Design (WSUD) measures can be implemented in priority areas with high risk from stormwater pollution based on the risk assessment undertaken. Distributed hazard control methods can be applied to reduce the generation of primary toxic pollutants, especially chromium (Cr) and heavy PAHs, through elimination and substitution measures. The percentage reduction in traffic volume required to mitigate the human health risk can be quantified through the risk models presented. The study outcomes will contribute to the development of efficient, targeted and reliable stormwater management strategies and to identify viable opportunities for stormwater reuse.
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Affiliation(s)
- Yukun Ma
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, 19 Xinjiekou Outer Street, Beijing, 100875, China; Science and Engineering Faculty, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, 4001 Queensland, Australia
| | - Kaveh Deilami
- Centre for Urban Research, School of Global, Urban and Social Studies, RMIT University, GPO Box 2476, Melbourne, Victoria 3001, Australia
| | - Prasanna Egodawatta
- Science and Engineering Faculty, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, 4001 Queensland, Australia
| | - An Liu
- Science and Engineering Faculty, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, 4001 Queensland, Australia; College of Chemistry and Environmental Engineering, Shenzhen University, 518060 Shenzhen, China
| | - James McGree
- Science and Engineering Faculty, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, 4001 Queensland, Australia
| | - Ashantha Goonetilleke
- Science and Engineering Faculty, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, 4001 Queensland, Australia.
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21
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Reverse QMRA as a Decision Support Tool: Setting Acceptable Concentration Limits for Pseudomonas aeruginosa and Naegleria fowleri. WATER 2019. [DOI: 10.3390/w11091850] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Opportunistic premise plumbing pathogens such as Pseudomonas aeruginosa and Naegleria fowleri are a growing concern in building water systems because of their potential risks to human health. The aim of this study was to determine the critical concentrations of P. aeruginosa and N. fowleri in water that are associated with meaningful public health risks. To determine these concentrations, a reverse quantitative microbial risk assessment (QMRA) was conducted. Environmental concentrations of P. aeruginosa and N. fowleri corresponding to the risk target of one micro-disability-adjusted life year (DALY) per person per year and 10−4 annual risks of illness were calculated for several applicable exposure scenarios. To calculate the concentration of P. aeruginosa, cleaning contact lenses with potentially contaminated tap water in the absence of an appropriate cleaning solution was considered. For N. fowleri, two exposure scenarios, recreational exposure (swimming) and nasal cleansing (via the use of a neti pot™ or similar device) were considered. The highest critical concentration for P. aeruginosa was found to be 33 CFU/L with a 95% confidence interval of (2.0, 118) for the drop exposure scenario using the 10−4 annual risk target. For N. fowleri, based on the DALY approach, critical concentrations were 0.000030 N. fowleri/L for swimming and 0.00000060 N. fowleri/L for neti pot™ use scenario. Considering heat inactivation, the critical concentration limits for P. aeruginosa using the DALY approach and the 10−4 annual risk target approach were found to be 0.55 CFU/L and 55 CFU/L, respectively. For N. fowleri, the 10−4 annual risk target approach resulted in 0.022 N. fowleri/L and the DALY approach resulted in 0.00000064 N. fowleri/L for the neti pot™ scenario. For P. aeruginosa, N50 (the median infective dose) and alpha (α) contributed the most and contact rates the least to the variability and uncertainty of the estimates for all the scenarios. For N. fowleri, N50 and contact rates contributed the most and α the least to the variability and uncertainty to calculate the concentrations for all the scenarios. The QMRA framework implemented in this research can be used to incorporate more information regarding opportunistic pathogens to inform management decisions, and to prioritize the best interventions regarding estimated reduction in infections caused by opportunistic pathogens.
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22
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Federigi I, Verani M, Donzelli G, Cioni L, Carducci A. The application of quantitative microbial risk assessment to natural recreational waters: A review. MARINE POLLUTION BULLETIN 2019; 144:334-350. [PMID: 31180003 DOI: 10.1016/j.marpolbul.2019.04.073] [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: 02/14/2019] [Revised: 04/26/2019] [Accepted: 04/28/2019] [Indexed: 06/09/2023]
Abstract
This review examines the aims of and approaches to the Quantitative Microbial Risk Assessment (QMRA) of untreated recreational waters. The literature search was conducted on four databases and yielded 54 papers, which were analyzed on a quantitative (time-trend, geographical distribution, water type) and qualitative (aims, source of microbial data, pathogens and their measurement or estimation, ways to address variability and uncertainty, sensitivity analysis) basis. In addition, the parameters, implications, and limitations were discussed for each QMRA step. Since 2003, the number of papers has greatly increased, highlighting the importance of QMRA for the risk management of recreational waters. Nevertheless, QMRA still exhibits critical issues, above all regarding contamination data and dose-response relationships. To our knowledge, this is the first review to give a wide panoramic view on QMRA in relation to recreational exposure to untreated waters. This could be useful in identifying the current knowledge gaps and research needs.
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Affiliation(s)
- Ileana Federigi
- QMRA Lab, Department of Biology, University of Pisa, Via S. Zeno 35/39, Pisa 56127, Italy.
| | - Marco Verani
- QMRA Lab, Department of Biology, University of Pisa, Via S. Zeno 35/39, Pisa 56127, Italy.
| | - Gabriele Donzelli
- QMRA Lab, Department of Biology, University of Pisa, Via S. Zeno 35/39, Pisa 56127, Italy.
| | - Lorenzo Cioni
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56123 Pisa, Italy.
| | - Annalaura Carducci
- QMRA Lab, Department of Biology, University of Pisa, Via S. Zeno 35/39, Pisa 56127, Italy.
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23
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Dowdell K, Haig SJ, Caverly LJ, Shen Y, LiPuma JJ, Raskin L. Nontuberculous mycobacteria in drinking water systems - the challenges of characterization and risk mitigation. Curr Opin Biotechnol 2019; 57:127-136. [PMID: 31003169 DOI: 10.1016/j.copbio.2019.03.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 03/05/2019] [Accepted: 03/05/2019] [Indexed: 12/18/2022]
Abstract
Nontuberculous mycobacteria (NTM) pulmonary infections are a growing concern worldwide, with a disproportionate incidence in persons with pre-existing health conditions. NTM have frequently been found in municipally-treated drinking water and building plumbing, leading to the hypothesis that an important source of NTM exposure is drinking water. The identification and quantification of NTM in environmental samples are complicated by genetic variability among NTM species, making it challenging to determine if clinically relevant NTM are present. Additionally, their unique cellular features and lifestyles make NTM and their nucleic acids difficult to recover. This review highlights a recent work focused on quantification and characterization of NTM and on understanding the influence of source water, treatment plants, distribution systems, and building plumbing on the abundance of NTM in drinking water.
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Affiliation(s)
- Katherine Dowdell
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Sarah-Jane Haig
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI, USA; Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Lindsay J Caverly
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Yun Shen
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI, USA
| | - John J LiPuma
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Lutgarde Raskin
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI, USA.
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Hamilton KA, Hamilton MT, Johnson W, Jjemba P, Bukhari Z, LeChevallier M, Haas CN, Gurian PL. Risk-Based Critical Concentrations of Legionella pneumophila for Indoor Residential Water Uses. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:4528-4541. [PMID: 30629886 DOI: 10.1021/acs.est.8b03000] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Legionella spp. is a key contributor to the United States waterborne disease burden. Despite potentially widespread exposure, human disease is relatively uncommon, except under circumstances where pathogen concentrations are high, host immunity is low, or exposure to small-diameter aerosols occurs. Water quality guidance values for Legionella are available for building managers but are generally not based on technical criteria. To address this gap, a quantitative microbial risk assessment (QMRA) was conducted using target risk values in order to calculate corresponding critical concentrations on a per-fixture and aggregate (multiple fixture exposure) basis. Showers were the driving indoor exposure risk compared to sinks and toilets. Critical concentrations depended on the dose response model (infection vs clinical severity infection, CSI), risk target used (infection risk vs disability adjusted life years [DALY] on a per-exposure or annual basis), and fixture type (conventional vs water efficient or "green"). Median critical concentrations based on exposure to a combination of toilet, faucet, and shower aerosols ranged from ∼10-2 to ∼100 CFU per L and ∼101 to ∼103 CFU per L for infection and CSI dose response models, respectively. As infection model results for critical L. pneumophila concentrations were often below a feasible detection limit for culture-based assays, the use of CSI model results for nonhealthcare water systems with a 10-6 DALY pppy target (the more conservative target) would result in an estimate of 12.3 CFU per L (arithmetic mean of samples across multiple fixtures and/or over time). Single sample critical concentrations with a per-exposure-corrected DALY target at each conventional fixture would be 1.06 × 103 CFU per L (faucets), 8.84 × 103 CFU per L (toilets), and 14.4 CFU per L (showers). Using a 10-4 annual infection risk target would give a 1.20 × 103 CFU per L mean for multiple fixtures and single sample critical concentrations of 1.02 × 105, 8.59 × 105, and 1.40 × 103 CFU per L for faucets, toilets, and showers, respectively. Annual infection risk-based target estimates are in line with most current guidance documents of less than 1000 CFU per L, while DALY-based guidance suggests lower critical concentrations might be warranted in some cases. Furthermore, approximately <10 CFU per mL L. pneumophila may be appropriate for healthcare or susceptible population settings. This analysis underscores the importance of the choice of risk target as well as sampling program considerations when choosing the most appropriate critical concentration for use in public health guidance.
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Affiliation(s)
- Kerry A Hamilton
- School for Sustainable Engineering and the Built Environment , Arizona State University , Tempe , Arizona 85281 , United States
- The Biodesign Institute Center for Environmental Health Engineering , Arizona State University , Tempe , Arizona 85281 , United States
| | - Mark T Hamilton
- Microsoft Applied Artificial Intelligence Group , 1 Memorial Drive , Cambridge , Massachusetts 02142 , United States
| | - William Johnson
- American Water Research Laboratory , 213 Carriage Lane , Delran , New Jersey 08075 , United States
| | - Patrick Jjemba
- American Water Research Laboratory , 213 Carriage Lane , Delran , New Jersey 08075 , United States
| | - Zia Bukhari
- American Water Research Laboratory , 213 Carriage Lane , Delran , New Jersey 08075 , United States
| | - Mark LeChevallier
- American Water Research Laboratory , 213 Carriage Lane , Delran , New Jersey 08075 , United States
| | - Charles N Haas
- Drexel University , 3141 Chestnut Street , Philadelphia , Pennsylvania 19104 , United States
| | - P L Gurian
- Drexel University , 3141 Chestnut Street , Philadelphia , Pennsylvania 19104 , United States
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25
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Rainwater Harvesting for Drinking Water Production: A Sustainable and Cost-Effective Solution in The Netherlands? WATER 2019. [DOI: 10.3390/w11030511] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
An increasing number of people want to reduce their environmental footprint by using harvested rainwater as a source for drinking water. Moreover, implementing rainwater harvesting (RWH) enables protection against damage caused by increasing precipitation frequency and intensity, which is predicted for Western Europe. In this study, literature data on rainwater quality were reviewed, and based on Dutch climatological data the usable quantity of rainwater in the Netherlands was calculated. For two specific cases, (1) a densely populated city district and (2) a single house in a rural area, the total costs of ownership (TCO) for decentralized drinking water supply from harvested rainwater was calculated, and a life cycle assessment (LCA) was made. For the single house it was found that costs were very high (€60–€110/m3), and the environmental impact would not decrease. For the city district, costs would be comparable to the present costs of centralized drinking water production and supply, but the environmental benefit is negligible (≤1‰). Furthermore, it was found that the amount of rainwater that can be harvested in the city district only covers about 50% of the demand. It was concluded that the application of rainwater harvesting for drinking water production in the Netherlands is not economically feasible.
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26
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Eslami M, Shafiei M, Ghasemian A, Valizadeh S, Al-Marzoqi AH, Shokouhi Mostafavi SK, Nojoomi F, Mirforughi SA. Mycobacterium avium paratuberculosis and Mycobacterium avium complex and related subspecies as causative agents of zoonotic and occupational diseases. J Cell Physiol 2019; 234:12415-12421. [PMID: 30673126 DOI: 10.1002/jcp.28076] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 12/07/2018] [Indexed: 12/23/2022]
Abstract
Mycobacterium avium complex (MAC) and Mycobacterium avium paratuberculosis (MAP) cause zoonotic infections transmitted by birds and livestock herds. These pathogens have remained as serious economic and health threats in most areas of the world. As zoonotic diseases, the risk of development of occupational disease and even death outcome necessitate implementation of control strategies to prevent its spread. Zoonotic MAP infections include Crohn's disease, inflammatory bowel disease, ulcerative colitis, sarcoidosis, diabetes mellitus, and immune-related diseases (such as Hashimoto's thyroiditis). Paratuberculosis has classified as type B epidemic zoonotic disease according to world health organization which is transmitted to human through consumption of dairy and meat products. In addition, MAC causes pulmonary manifestations and lymphadenitis in normal hosts and human immunodeficiency virus (HIV) progression (by serotypes 1, 4, and 8). Furthermore, other subspecies have caused respiratory abscesses, neck lymph nodes, and disseminated osteomyelitis in children and ulcers. However, the data over the occupational relatedness of these subspecies is rare. These agents can cause occupational infections in susceptible herd breeders. Several molecular methods have been recognized as proper strategies for tracking the infection. In this study, some zoonotic aspects, worldwide prevalence and control strategies regarding infections due to MAP and MAC and related subspecies has been reviewed.
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Affiliation(s)
- Majid Eslami
- Department of Bacteriology and Virology, Semnan University of Medical Sciences, Semnan, Iran
| | - Morvarid Shafiei
- Department of Microbiology, Pasteur Institute of Iran, Tehran, Iran
| | - Abdolmajid Ghasemian
- Department of Biology, Central Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Saeid Valizadeh
- Department of Bacteriology and Virology, Semnan University of Medical Sciences, Semnan, Iran
| | | | | | - Farshad Nojoomi
- Microbiology Department, Faculty of Medicine, AJA University of Medical Sciences, Tehran, Iran
| | - Seyede Amene Mirforughi
- Social Determinants of Health Research Center, Shahrekord University of Medical Sciences, Shahrekord, Iran
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27
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Facciponte DN, Bough MW, Seidler D, Carroll JL, Ashare A, Andrew AS, Tsongalis GJ, Vaickus LJ, Henegan PL, Butt TH, Stommel EW. Identifying aerosolized cyanobacteria in the human respiratory tract: A proposed mechanism for cyanotoxin-associated diseases. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 645:1003-1013. [PMID: 30248825 PMCID: PMC6159226 DOI: 10.1016/j.scitotenv.2018.07.226] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/12/2018] [Accepted: 07/17/2018] [Indexed: 05/10/2023]
Abstract
Cyanobacteria produce harmful toxins that have been associated with several acute conditions and chronic human diseases, like gastroenteritis, non-alcoholic liver disease, and amyotrophic lateral sclerosis. Aerosol from waterbodies appears to be a likely mechanism for exposure. We conducted a study of human biospecimens focused on the cyanobacterial aerosilization process by evaluating the extent to which cyanobacteria can invade the human respiratory tract. Our study suggests that humans routinely inhale aerosolized cyanobacteria, which can be harbored in the nostrils and the lungs. Using PCR, cyanobacteria were found at high frequencies in the upper respiratory tract (92.20%) and central airway (79.31%) of our study subjects. Nasal swabs were not predictive of bronchoalveolar lavage (BAL) when detecting inhaled cyanobacteria. Interestingly, we found no evidence that time of year was a significant factor for cyanobacteria positivity (BAL cytology p = 1.0 and PCR p = 1.0); (nasal swab cytology p = 0.051 and PCR p = 0.65). Additionally, we found that proximity to a waterbody was not a significant factor for cyanobacteria positivity in BAL and nasal swabs collected during cyanobacteria bloom season [May-October] (p = 0.46 and p = 0.38). These data suggest that cyanobacteria exposure may be a prevalent and chronic phenomenon not necessarily restricted to waterbodies alone. Sources of indoor exposure warrant future investigation. Given the widespread prevalence of cyanobacterial exposure in the airway, investigation of the aerosol spread of cyanotoxins, more specifically, is warranted. Our findings are consistent with the hypothesis that aerosol is a significant route for cyanobacteria exposure, and thus a likely route of transmission for cyanotoxin-associated human diseases.
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Affiliation(s)
- Dominic N Facciponte
- Dartmouth-Hitchcock Medical Center, Department of Neurology, One Medical Center Dr., Lebanon, NH 03756, USA.
| | - Matthew W Bough
- Dartmouth-Hitchcock Medical Center, Department of Neurology, One Medical Center Dr., Lebanon, NH 03756, USA; Dartmouth College, Hanover, NH 03755, USA
| | - Darius Seidler
- Dartmouth-Hitchcock Medical Center, Department of Pulmonary and Critical Care Medicine, One Medical Center Dr., Lebanon, NH 03756, USA; Geisel School of Medicine at Dartmouth, One Rope Ferry Rd., Hanover, NH 03755, USA
| | - James L Carroll
- Dartmouth-Hitchcock Medical Center, Department of Pulmonary and Critical Care Medicine, One Medical Center Dr., Lebanon, NH 03756, USA; Geisel School of Medicine at Dartmouth, One Rope Ferry Rd., Hanover, NH 03755, USA
| | - Alix Ashare
- Dartmouth-Hitchcock Medical Center, Department of Pulmonary and Critical Care Medicine, One Medical Center Dr., Lebanon, NH 03756, USA; Geisel School of Medicine at Dartmouth, One Rope Ferry Rd., Hanover, NH 03755, USA
| | - Angeline S Andrew
- Dartmouth-Hitchcock Medical Center, Department of Neurology, One Medical Center Dr., Lebanon, NH 03756, USA; Geisel School of Medicine at Dartmouth, One Rope Ferry Rd., Hanover, NH 03755, USA
| | - Gregory J Tsongalis
- Dartmouth-Hitchcock Medical Center, Department of Pathology and Laboratory Medicine, One Medical Center Dr., Lebanon, NH 03756, USA; Geisel School of Medicine at Dartmouth, One Rope Ferry Rd., Hanover, NH 03755, USA
| | - Louis J Vaickus
- Dartmouth-Hitchcock Medical Center, Department of Pathology and Laboratory Medicine, One Medical Center Dr., Lebanon, NH 03756, USA; Geisel School of Medicine at Dartmouth, One Rope Ferry Rd., Hanover, NH 03755, USA
| | - Patricia L Henegan
- Dartmouth-Hitchcock Medical Center, Department of Neurology, One Medical Center Dr., Lebanon, NH 03756, USA
| | - Tanya H Butt
- Dartmouth-Hitchcock Medical Center, Department of Neurology, One Medical Center Dr., Lebanon, NH 03756, USA
| | - Elijah W Stommel
- Dartmouth-Hitchcock Medical Center, Department of Neurology, One Medical Center Dr., Lebanon, NH 03756, USA; Geisel School of Medicine at Dartmouth, One Rope Ferry Rd., Hanover, NH 03755, USA.
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Honda JR, Virdi R, Chan ED. Global Environmental Nontuberculous Mycobacteria and Their Contemporaneous Man-Made and Natural Niches. Front Microbiol 2018; 9:2029. [PMID: 30214436 PMCID: PMC6125357 DOI: 10.3389/fmicb.2018.02029] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 08/10/2018] [Indexed: 11/15/2022] Open
Abstract
Seminal microbiological work of environmental nontuberculous mycobacteria (NTM) includes the discovery that NTM inhabit water distribution systems and soil, and that the species of NTM found are geographically diverse. It is likely that patients acquire their infections from repeated exposures to their environments, based on the well-accepted paradigm that water and soil bioaerosols - enriched for NTM - can be inhaled into the lungs. Support comes from reports demonstrating NTM isolated from the lungs of patients are genetically identical to NTM found in their environment. Well documented sources of NTM include peat-rich soils, natural waters, drinking water, hot water heaters, refrigerator taps, catheters, and environmental amoeba. However, NTM have also been recovered in biofilms from ice machines, heated nebulizers, and heater-cooler units, as well as seat dust from theaters, vacuum cleaners, and cobwebs. New studies on the horizon aim to significantly expand the current knowledge of environmental NTM niches in order to improve our current understanding of the specific ecological factors driving the emergence of NTM lung disease. Specifically, the Hawaiian Island environment is currently being studied as a model to identify other point sources of exposure as it is the U.S. state with the highest number of NTM lung disease cases. Because of its geographic isolation and unique ecosystem, the Hawaiian environment is being probed for correlative factors that may promote environmental NTM colonization.
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Affiliation(s)
- Jennifer R. Honda
- Department of Biomedical Research and the Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, United States
| | - Ravleen Virdi
- Department of Biomedical Research and the Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, United States
| | - Edward D. Chan
- Medicine and Academic Affairs, National Jewish Health, Denver, CO, United States
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Denver, Aurora, CO, United States
- Department of Medicine, Denver Veterans Affairs Medical Center, Denver, CO, United States
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29
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Steege L, Moore G. The presence and prevalence of Legionella spp in collected rainwater and its aerosolisation during common gardening activities. Perspect Public Health 2018; 138:254-260. [PMID: 29969060 DOI: 10.1177/1757913918786322] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
AIMS To determine the presence and prevalence of Legionella spp in domestic rainwater storage butts and to quantify its aerosolisation when collected rainwater is used for common gardening activities. METHODS Volunteers were asked to take a water sample from their garden rainwater storage butt. The presence of Legionella was determined using quantitative polymerase chain reaction (qPCR). Two new rainwater storage butts were installed on-site at PHE Porton and positioned in sunlight or in the shade. Ambient conditions and those within the two 'experimental' water butts were continually monitored. A cyclone air sampler was used to detect the presence of Legionella in the air when collected rainwater was poured from a watering can or delivered via a hosepipe attached to a submersible water butt pump. RESULTS A total of 63 volunteers provided water samples from 113 different rainwater storage butts. Legionella spp was detected in 107 of these samples at a mean concentration of 4.7 × 104 genomic units l-1. Two of these samples also contained L. pneumophila. The water butt positioned in the shade stored water at a significantly lower temperature than that exposed to sunlight. While the concentration of Legionella was significantly higher in this cooler water, meteorological conditions rather than conditions within the water butt had the greatest effect upon Legionella concentration. No Legionella was detected in the air when rainwater was poured from a watering can. However, using a hose pipe on a 'fine spray' setting increased both the number of organisms detected in the air and their dissemination. CONCLUSION In this study, Legionella spp were common contaminants of collected rainwater. However, the use of rainwater for common gardening activities should not be discouraged. Aerosolisation of Legionella when using a watering can is minimal and any increased risk associated with hose pipe use can be mitigated by using a coarse spray setting.
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Affiliation(s)
- L Steege
- Biosafety, Air and Water Microbiology Group, National Infection Service, Public Health England, Salisbury, UK.,School of Biosciences and Medicine, University of Surrey, Guildford, UK
| | - G Moore
- Biosafety, Air and Water Microbiology Group, National Infection Service, Public Health England, Porton Down, Salisbury SP4 0JG, UK
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30
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Hamilton KA, Prussin AJ, Ahmed W, Haas CN. Outbreaks of Legionnaires’ Disease and Pontiac Fever 2006–2017. Curr Environ Health Rep 2018; 5:263-271. [DOI: 10.1007/s40572-018-0201-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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31
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Hamilton KA, Hamilton MT, Johnson W, Jjemba P, Bukhari Z, LeChevallier M, Haas CN. Health risks from exposure to Legionella in reclaimed water aerosols: Toilet flushing, spray irrigation, and cooling towers. WATER RESEARCH 2018; 134:261-279. [PMID: 29428779 DOI: 10.1016/j.watres.2017.12.022] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 11/30/2017] [Accepted: 12/12/2017] [Indexed: 05/05/2023]
Abstract
The use of reclaimed water brings new challenges for the water industry in terms of maintaining water quality while increasing sustainability. Increased attention has been devoted to opportunistic pathogens, especially Legionella pneumophila, due to its growing importance as a portion of the waterborne disease burden in the United States. Infection occurs when a person inhales a mist containing Legionella bacteria. The top three uses for reclaimed water (cooling towers, spray irrigation, and toilet flushing) that generate aerosols were evaluated for Legionella health risks in reclaimed water using quantitative microbial risk assessment (QMRA). Risks are compared using data from nineteen United States reclaimed water utilities measured with culture-based methods, quantitative PCR (qPCR), and ethidium-monoazide-qPCR. Median toilet flushing annual infection risks exceeded 10-4 considering multiple toilet types, while median clinical severity infection risks did not exceed this value. Sprinkler and cooling tower risks varied depending on meteorological conditions and operational characteristics such as drift eliminator performance. However, the greatest differences between risk scenarios were due to 1) the dose response model used (infection or clinical severity infection) 2) population at risk considered (residential or occupational) and 3) differences in laboratory analytical method. Theoretical setback distances necessary to achieve a median annual infection risk level of 10-4 are proposed for spray irrigation and cooling towers. In both cooling tower and sprinkler cases, Legionella infection risks were non-trivial at potentially large setback distances, and indicate other simultaneous management practices could be needed to manage risks. The sensitivity analysis indicated that the most influential factors for variability in risks were the concentration of Legionella and aerosol partitioning and/or efficiency across all models, highlighting the importance of strategies to manage Legionella occurrence in reclaimed water.
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Affiliation(s)
- Kerry A Hamilton
- Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA.
| | | | - William Johnson
- American Water Research Laboratory, 213 Carriage Lane, Delran, New Jersey 08075, USA
| | - Patrick Jjemba
- American Water Research Laboratory, 213 Carriage Lane, Delran, New Jersey 08075, USA
| | - Zia Bukhari
- American Water Research Laboratory, 213 Carriage Lane, Delran, New Jersey 08075, USA
| | - Mark LeChevallier
- American Water Research Laboratory, 213 Carriage Lane, Delran, New Jersey 08075, USA
| | - Charles N Haas
- Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
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Assessment of Water Quality in Roof-Harvested Rainwater Barrels in Greater Philadelphia. WATER 2018. [DOI: 10.3390/w10020092] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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A Review of Roof Harvested Rainwater in Australia. JOURNAL OF ENVIRONMENTAL AND PUBLIC HEALTH 2018; 2018:6471324. [PMID: 29606962 PMCID: PMC5828256 DOI: 10.1155/2018/6471324] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 11/15/2017] [Accepted: 11/20/2017] [Indexed: 12/19/2022]
Abstract
To address concern regarding water sustainability, the Australian Federal Government and many state governments have implemented regulatory mechanisms and incentives to support households to purchase and install rainwater harvesting systems. This has led to an increase in rainwater harvesting in regional and urban Australia. This review examines the implementation of the regulatory mechanisms across Australia. In addition, the literature investigating the potential health consequences of rainwater consumption in Australia was explored. Studies demonstrated that although trace metals such as arsenic, cadmium, chromium, lead, and iron were present in Australian rainwater, these metallic elements were generally found below the health limit guideline, except in high industrial areas. In addition, pathogenic or indicator microorganisms that include, but are not limited to, Escherichia coli, total and faecal coliforms, Campylobacter, Salmonella, Legionella, Pseudomonas, Cryptosporidium, Enterococci, Giardia, Aeromonas, and Mycobacterium avium Complex (MAC) have been detected in rainwater collected in Australia. However, epidemiological evidence suggests that drinking rainwater does not increase the risk of gastrointestinal disease. It was also identified that there is a need for further research investigating the potential for rainwater to be a source of infection for opportunistic pathogens.
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Murphy HM, Meng Z, Henry R, Deletic A, McCarthy DT. Current Stormwater Harvesting Guidelines Are Inadequate for Mitigating Risk from Campylobacter During Nonpotable Reuse Activities. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:12498-12507. [PMID: 29035523 DOI: 10.1021/acs.est.7b03089] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Campylobacter is a pathogen frequently detected in urban stormwater worldwide. It is one of the leading causes of enteric disease in many developed countries and is the leading cause of enteric disease in Australia. Prior to harvesting stormwater, adequate treatment is necessary to mitigate risks derived from such harmful pathogens. The goal of this research was to estimate the health risks associated with the exposure to Campylobacter when harvesting urban stormwater for toilet flushing and irrigation activities, and the role treatment options play in limiting risks. Campylobacter data collected from several urban stormwater systems in Victoria, Australia, were the inputs of a Quantitative Microbial Risk Assessment model. The model included seven treatment scenarios, spanning wetlands, biofilters, and more traditional treatment trains including those recommended by the Australian Guidelines for Water Recycling. According to our modeling and acceptable risk thresholds, only two treatment scenarios could supply water of sufficient quality for toilet flushing and irrigation end-uses: (1) using stormwater biofilters coupled with UV-treatment and (2) a more conventional coagulation, filtration, UV, and chlorination treatment plant. Importantly, our modeling results suggest that current guidelines in place for stormwater reuse are not adequate for protecting against exposure to Campylobacter. However, more research is required to better define whether the Campylobacter detectable in stormwater are pathogenic to humans.
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Affiliation(s)
- Heather M Murphy
- Division of Environmental Health, College of Public Health, Temple University , Philadelphia, Pennsylvania 19122, United States
| | - Ze Meng
- Environmental and Public Health Microbiology Laboratory (EPHM Lab), Department of Civil Engineering, Monash Infrastructure Institute, Monash University , Clayton, Victoria 3800, Australia
| | - Rebekah Henry
- Environmental and Public Health Microbiology Laboratory (EPHM Lab), Department of Civil Engineering, Monash Infrastructure Institute, Monash University , Clayton, Victoria 3800, Australia
| | - Ana Deletic
- Environmental and Public Health Microbiology Laboratory (EPHM Lab), Department of Civil Engineering, Monash Infrastructure Institute, Monash University , Clayton, Victoria 3800, Australia
| | - David T McCarthy
- Environmental and Public Health Microbiology Laboratory (EPHM Lab), Department of Civil Engineering, Monash Infrastructure Institute, Monash University , Clayton, Victoria 3800, Australia
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Prussin AJ, Schwake DO, Marr LC. Ten Questions Concerning the Aerosolization and Transmission of Legionella in the Built Environment. BUILDING AND ENVIRONMENT 2017; 123:684-695. [PMID: 29104349 PMCID: PMC5665586 DOI: 10.1016/j.buildenv.2017.06.024] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Legionella is a genus of pathogenic Gram-negative bacteria responsible for a serious disease known as legionellosis, which is transmitted via inhalation of this pathogen in aerosol form. There are two forms of legionellosis: Legionnaires' disease, which causes pneumonia-like symptoms, and Pontiac fever, which causes influenza-like symptoms. Legionella can be aerosolized from various water sources in the built environment including showers, faucets, hot tubs/swimming pools, cooling towers, and fountains. Incidence of the disease is higher in the summertime, possibly because of increased use of cooling towers for air conditioning systems and differences in water chemistry when outdoor temperatures are higher. Although there have been decades of research related to Legionella transmission, many knowledge gaps remain. While conventional wisdom suggests that showering is an important source of exposure in buildings, existing measurements do not provide strong support for this idea. There has been limited research on the potential for Legionella transmission through heating, ventilation, and air conditioning (HVAC) systems. Epidemiological data suggest a large proportion of legionellosis cases go unreported, as most people who are infected do not seek medical attention. Additionally, controlled laboratory studies examining water-to-air transfer and source tracking are still needed. Herein, we discuss ten questions that spotlight current knowledge about Legionella transmission in the built environment, engineering controls that might prevent future disease outbreaks, and future research that is needed to advance understanding of transmission and control of legionellosis.
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Affiliation(s)
- Aaron J. Prussin
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
- Corresponding Author:
| | - David Otto Schwake
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Linsey C. Marr
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
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