35 results on '"Andrea I. Silverman"'
Search Results
2. Systematic review of the relative concentrations of noroviruses and fecal indicator bacteria in wastewater: considerations for use in quantitative microbial risk assessment
- Author
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Zelfa Hamadieh, Kerry A. Hamilton, and Andrea I. Silverman
- Subjects
fecal indicator bacteria ,norovirus ,quantitative microbial risk assessment (qmra) ,wastewater treatment ,Public aspects of medicine ,RA1-1270 - Abstract
Human noroviruses are a leading cause of food- and water-borne disease, which has led to an interest in quantifying norovirus health risks using quantitative microbial risk assessment (QMRA). Given the limited availability of quantitative norovirus data to input to QMRA models, some studies have applied a conversion factor to estimate norovirus exposure based on measured fecal indicator bacteria (FIB) concentrations. We conducted a review of peer-reviewed publications to identify the concentrations of noroviruses and FIB in raw, secondary-treated, and disinfected wastewater. A meta-analysis was performed to determine the ratios of norovirus-FIB pairs in each wastewater matrix and the variables that significantly impact these ratios. Norovirus-to-FIB ratios were found to be significantly impacted by the norovirus genotype, month of sample collection, geographic location, and the extent of wastewater treatment. Additionally, we evaluated the impact of using a FIB-to-virus conversion factor in QMRA and found that the choice of conversion ratio has a great impact on estimated health risks. For example, the use of a conversion ratio previously used in the World Health Organization Guidelines for the Safe Use of Wastewater, Excreta and Greywater predicted health risks that were significantly lower than those estimated with measured norovirus concentrations used as inputs. This work emphasizes the gold standard of using measured pathogen concentrations directly as inputs to exposure assessment in QMRA. While not encouraged, if one must use a FIB-to-virus conversion ratio to estimate norovirus dose, the ratio should be chosen carefully based on the target microorganisms (i.e., strain, genotype, or class), prevalence of disease, and extent of wastewater treatment. HIGHLIGHTS It is inappropriate to use a static ratio to estimate norovirus concentrations based on measured fecal indicator bacteria (FIB) abundances in all cases.; Calculated ratios between measured norovirus and FIB differed depending on the virus genotype and FIB class considered. Ratios were significantly influenced by the extent of wastewater treatment.; The gold standard is to use measured pathogen concentrations directly as inputs to exposure assessment in quantitative microbial risk assessment.; more...
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- 2021
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- View/download PDF
Catalog
3. SARS-CoV-2 Wastewater Surveillance for Public Health Action
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Jill S. McClary-Gutierrez, Mia C. Mattioli, Perrine Marcenac, Andrea I. Silverman, Alexandria B. Boehm, Kyle Bibby, Michael Balliet, Francis L. de los Reyes, Daniel Gerrity, John F. Griffith, Patricia A. Holden, Dimitrios Katehis, Greg Kester, Nathan LaCross, Erin K. Lipp, Jonathan Meiman, Rachel T. Noble, Dominique Brossard, and Sandra L. McLellan more...
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COVID-19 ,coronavirus disease ,SARS-CoV-2 ,severe acute respiratory syndrome coronavirus 2 ,viruses ,respiratory infections ,Medicine ,Infectious and parasitic diseases ,RC109-216 - Abstract
Wastewater surveillance for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has garnered extensive public attention during the coronavirus disease pandemic as a proposed complement to existing disease surveillance systems. Over the past year, methods for detection and quantification of SARS-CoV-2 viral RNA in untreated sewage have advanced, and concentrations in wastewater have been shown to correlate with trends in reported cases. Despite the promise of wastewater surveillance, for these measurements to translate into useful public health tools, bridging the communication and knowledge gaps between researchers and public health responders is needed. We describe the key uses, barriers, and applicability of SARS-CoV-2 wastewater surveillance for supporting public health decisions and actions, including establishing ethics consideration for monitoring. Although wastewater surveillance to assess community infections is not a new idea, the coronavirus disease pandemic might be the initiating event to make this emerging public health tool a sustainable nationwide surveillance system, provided that these barriers are addressed. more...
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- 2021
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4. Engineering an Interdisciplinary Connection: Bridging Gaps between Chemical, Electrical, and Environmental Engineers
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Yury Dvorkin, Miguel A. Modestino, and Andrea I. Silverman
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Science - Published
- 2020
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5. Assessment of Commonly Measured Wastewater Parameters to Estimate Sewershed Populations for Use in Wastewater-Based Epidemiology: Insights into Population Dynamics in New York City during the COVID-19 Pandemic
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Catherine Hoar, Yitao Li, and Andrea I. Silverman
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Chemistry (miscellaneous) ,Environmental Chemistry ,Chemical Engineering (miscellaneous) ,Water Science and Technology - Published
- 2022
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6. Effect of pH on endogenous sunlight inactivation rates of laboratory strain and wastewater sourced E. coli and enterococci
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Mwale Chiyenge and Andrea I. Silverman
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Public Health, Environmental and Occupational Health ,Environmental Chemistry ,General Medicine ,Management, Monitoring, Policy and Law - Abstract
Solution pH was observed to impact the solar disinfection rates of key fecal indicator bacteria in a sensitizer-free water matrix, with elevated solar disinfection rates observed at the pH extremes. more...
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- 2022
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7. Monitoring SARS-CoV-2 in wastewater during New York City's second wave of COVID-19: sewershed-level trends and relationships to publicly available clinical testing data
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Catherine Hoar, Francoise Chauvin, Alexander Clare, Hope McGibbon, Esmeraldo Castro, Samantha Patinella, Dimitrios Katehis, John J. Dennehy, Monica Trujillo, Davida S. Smyth, and Andrea I. Silverman
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Environmental Engineering ,viruses ,Water Science and Technology - Abstract
New York City’s ongoing wastewater monitoring program tracked trends in sewershed-level SARS-CoV-2 loads starting in the fall of 2020, just before the start of the City’s second wave of the COVID-19 outbreak. During a five-month study period, from November 8, 2020 to April 11, 2021, viral loads in influent wastewater from each of New York City’s 14 wastewater treatment plants were measured and compared to new laboratory-confirmed COVID-19 cases for the populations in each corresponding sewershed, estimated from publicly available clinical testing data. We found significant positive correlations between viral loads in wastewater and new COVID-19 cases. The strength of the correlations varied depending on the sewershed, with Spearman’s rank correlation coefficients ranging between 0.38 and 0.81 (mean = 0.55). Based on a linear regression analysis of a combined data set for New York City, we found that a 1 log10 change in the SARS-CoV-2 viral load in wastewater corresponded to a 0.6 log10 change in the number of new laboratory-confirmed COVID-19 cases/day in a sewershed. An estimated minimum detectable case rate between 2 - 8 cases/day/100,000 people was associated with the method limit of detection in wastewater. This work offers a preliminary assessment of the relationship between wastewater monitoring data and clinical testing data in New York City. While routine monitoring and method optimization continue, information on the development of New York City’s ongoing wastewater monitoring program may provide insights for similar wastewater-based epidemiology efforts in the future. more...
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- 2022
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8. Escherichia coli and Enterococcus spp. Indigenous to Wastewater Have Slower Free Chlorine Disinfection Rates than Their Laboratory-Cultured Counterparts
- Author
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Andrea I. Silverman and Mwanarusi H. Mwatondo
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Ecology ,biology ,Chemistry ,Health, Toxicology and Mutagenesis ,chemistry.chemical_element ,biology.organism_classification ,medicine.disease_cause ,Pollution ,Wastewater ,polycyclic compounds ,Enterococcus spp ,medicine ,Chlorine ,Environmental Chemistry ,Food science ,Waste Management and Disposal ,Escherichia coli ,Bacteria ,Water Science and Technology - Abstract
Most published data on chlorine disinfection of bacteria are from experiments conducted using reference-strain bacteria cultured in a laboratory. However, indigenous environmental bacteria, such as... more...
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- 2021
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9. Systematic review of the relative concentrations of noroviruses and fecal indicator bacteria in wastewater: considerations for use in quantitative microbial risk assessment
- Author
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Kerry A. Hamilton, Zelfa Hamadieh, and Andrea I. Silverman
- Subjects
quantitative microbial risk assessment (qmra) ,Microbiology (medical) ,Bacteria ,viruses ,fecal indicator bacteria ,Norovirus ,Public Health, Environmental and Occupational Health ,Indicator bacteria ,Wastewater ,Biology ,Risk Assessment ,wastewater treatment ,Feces ,fluids and secretions ,Infectious Diseases ,Microbial risk ,Humans ,Food science ,Public aspects of medicine ,RA1-1270 ,Water Microbiology ,Waste Management and Disposal ,Water Science and Technology - Abstract
Human noroviruses are a leading cause of food- and water-borne disease, which has led to an interest in quantifying norovirus health risks using quantitative microbial risk assessment (QMRA). Given the limited availability of quantitative norovirus data to input to QMRA models, some studies have applied a conversion factor to estimate norovirus exposure based on measured fecal indicator bacteria (FIB) concentrations. We conducted a review of peer-reviewed publications to identify the concentrations of noroviruses and FIB in raw, secondary-treated, and disinfected wastewater. A meta-analysis was performed to determine the ratios of norovirus-FIB pairs in each wastewater matrix and the variables that significantly impact these ratios. Norovirus-to-FIB ratios were found to be significantly impacted by the norovirus genotype, month of sample collection, geographic location, and the extent of wastewater treatment. Additionally, we evaluated the impact of using a FIB-to-virus conversion factor in QMRA and found that the choice of conversion ratio has a great impact on estimated health risks. For example, the use of a conversion ratio previously used in the World Health Organization Guidelines for the Safe Use of Wastewater, Excreta and Greywater predicted health risks that were significantly lower than those estimated with measured norovirus concentrations used as inputs. This work emphasizes the gold standard of using measured pathogen concentrations directly as inputs to exposure assessment in QMRA. While not encouraged, if one must use a FIB-to-virus conversion ratio to estimate norovirus dose, the ratio should be chosen carefully based on the target microorganisms (i.e., strain, genotype, or class), prevalence of disease, and extent of wastewater treatment. HIGHLIGHTS It is inappropriate to use a static ratio to estimate norovirus concentrations based on measured fecal indicator bacteria (FIB) abundances in all cases.; Calculated ratios between measured norovirus and FIB differed depending on the virus genotype and FIB class considered. Ratios were significantly influenced by the extent of wastewater treatment.; The gold standard is to use measured pathogen concentrations directly as inputs to exposure assessment in quantitative microbial risk assessment. more...
- Published
- 2021
- Full Text
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10. Sunlight Photolysis of Extracellular and Intracellular Antibiotic Resistance Genes tetA and sul2 in Photosensitizer-Free Water
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Andrea I. Silverman and Fiona B. Dunn
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biology ,Chemistry ,General Chemistry ,Amplicon ,biology.organism_classification ,medicine.disease_cause ,chemistry.chemical_compound ,Antibiotic resistance ,Biochemistry ,medicine ,Extracellular ,Environmental Chemistry ,Photosensitizer ,Escherichia coli ,Bacteria ,Intracellular ,DNA - Abstract
Antibiotic resistance genes (ARGs; the genetic material in bacteria that encode for resistance to antibiotics) have been found in the aquatic environment, raising concerns of an environmental transmission route. In an effort to contribute to models predicting the fate of ARGs in the environment-to design control measures, predict health risks, inform ARG surveillance activities, and prioritize policy interventions-and given the importance of sunlight in damaging DNA, we evaluated the sunlight photolysis kinetics of antibiotic-resistant bacteria (ARB) and ARGs under laboratory conditions, focusing on Escherichia coli SMS-3-5 and its ARGs tetA and sul2. Experiments were conducted in the absence of photosensitizers, and ARG decay rates were quantified by quantitative polymerase chain reaction (qPCR) with short and long amplicon targets. Long amplicon qPCR targets quantified greater photolysis rate constants, due to greater ARG coverage. After a lag phase, intracellular ARG had faster decay rates than extracellular ARG, likely due to the contribution of intracellular indirect photolysis processes. Furthermore, all ARG decay rates were significantly slower than those of E. coli. Decay rate constants and quantum yields are presented as foundational work in the development of models to describe the persistence of ARGs in sunlit, environmental waters. more...
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- 2021
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11. Looking Forward: The Role of Academic Researchers in Building Sustainable Wastewater Surveillance Programs
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Catherine Hoar, Jill McClary-Gutierrez, Marlene K. Wolfe, Aaron Bivins, Kyle Bibby, Andrea I. Silverman, and Sandra L. McLellan
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Wastewater-Based Epidemiological Monitoring ,SARS-CoV-2 ,Health, Toxicology and Mutagenesis ,microbiology ,Public Health, Environmental and Occupational Health ,Humans ,COVID-19 ,RNA, Viral ,Wastewater ,Pandemics ,United States - Abstract
In just over 2 years, tracking the COVID-19 pandemic through wastewater surveillance advanced from early reports of successful SARS-CoV-2 RNA detection in untreated wastewater to implementation of programs in at least 60 countries. Early wastewater monitoring efforts primarily originated in research laboratories and are now transitioning into more formal surveillance programs run in commercial and public health laboratories. A major challenge in this progression has been to simultaneously optimize methods and build scientific consensus while implementing surveillance programs, particularly during the rapidly changing landscape of the pandemic. Translating wastewater surveillance results for effective use by public health agencies also remains a key objective for the field.We examined the evolution of wastewater surveillance to identify model collaborations and effective partnerships that have created rapid and sustained success. We propose needed areas of research and key roles academic researchers can play in the framework of wastewater surveillance to aid in the transition from early monitoring efforts to more formalized programs within the public health system.Although wastewater surveillance has rapidly developed as a useful public health tool for tracking COVID-19, there remain technical challenges and open scientific questions that academic researchers are equipped to address. This includes validating methodology and backfilling important knowledge gaps, such as fate and transport of surveillance targets and epidemiological links to wastewater concentrations. Our experience in initiating and implementing wastewater surveillance programs in the United States has allowed us to reflect on key barriers and draw useful lessons on how to promote synergy between different areas of expertise. As wastewater surveillance programs are formalized, the working relationships developed between academic researchers, commercial and public health laboratories, and data users should promote knowledge co-development. We believe active involvement of academic researchers will contribute to building robust surveillance programs that will ultimately provide new insights into population health. https://doi.org/10.1289/EHP11519. more...
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- 2022
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12. Cleaner water with light
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Andrea I. Silverman and Jeremy S. Guest
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Urban Studies ,Global and Planetary Change ,Ecology ,Renewable Energy, Sustainability and the Environment ,Geography, Planning and Development ,Management, Monitoring, Policy and Law ,Nature and Landscape Conservation ,Food Science - Published
- 2022
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13. Systematic Review and Meta-Analysis of the Persistence of Enveloped Viruses in Environmental Waters and Wastewater in the Absence of Disinfectants
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Alexandria B. Boehm and Andrea I. Silverman
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biology ,Paramyxoviridae ,Orthomyxoviridae ,Filoviridae ,General Chemistry ,Wastewater ,biology.organism_classification ,Virology ,Pneumoviridae ,Disease Outbreaks ,Togaviridae ,Viruses ,Environmental Chemistry ,Coronaviridae ,Animals ,Humans ,Poxviridae ,Pandemics ,Virus classification ,Disinfectants - Abstract
Enveloped viruses are characterized by a lipid-containing envelope that encapsulates the virion, and they have been the cause of major outbreaks and pandemics. Some enveloped viruses are excreted in feces and other bodily fluids of infected people and animals, raising the question of their fate in the aquatic environment. Consequently, we conducted a systematic review and meta-analysis of the decay rate constants (k) of enveloped viruses from 12 families (i.e., Coronaviridae, Cystoviridae (specifically Phi6), Filoviridae, Hepadnaviridae, Herpesviridae, Orthomyxoviridae, Paramyxoviridae, Pneumoviridae, Poxviridae, Retroviridae, Rhabdoviridae, Togaviridae) in environmental waters and wastewater to evaluate their decay kinetics and identify the environmental and virus characteristics that influence k. A total of 812 k that met inclusion criteria were identified in the literature, with the number of k for each family ranging from 0 to 560, and the virus family averaged values of k ranging from 0.11 d-1 and 1.85 d-1. Virus type (i.e., genus, species, subspecies, or subtype), method of virus enumeration (i.e., culture-based or (RT-)QPCR), and experimental water matrix type, temperature and sterility were found to have significant effects on k. Additionally, enveloped viruses were found to have statistically significantly greater k than nonenveloped viruses. Multiple linear regression models that allow prediction of log10k as a function of virus type, enumeration method, water temperature, and water type are provided for six virus families that had sufficient data available for model fitting (i.e., Coronaviridae, Phi6, Herpesviridae, Orthomyxoviridae, Rhabdoviridae, Togaviridae). Compiled log10k and multiple regression models can be used to inform management of human and animal waste, operation of water and wastewater facilities, and exposure risks to treatment plant workers and communities living in regions that lack treatment facilities. Given limited data available for some enveloped virus families with a potential water-related transmission route, there is need for additional data collection to aid academic researchers, public health agencies, and water and wastewater professionals involved in outbreak response. more...
- Published
- 2021
14. Sunlight Photolysis of Extracellular and Intracellular Antibiotic Resistance Genes
- Author
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Fiona B, Dunn and Andrea I, Silverman
- Abstract
Antibiotic resistance genes (ARGs; the genetic material in bacteria that encode for resistance to antibiotics) have been found in the aquatic environment, raising concerns of an environmental transmission route. In an effort to contribute to models predicting the fate of ARGs in the environment-to design control measures, predict health risks, inform ARG surveillance activities, and prioritize policy interventions-and given the importance of sunlight in damaging DNA, we evaluated the sunlight photolysis kinetics of antibiotic-resistant bacteria (ARB) and ARGs under laboratory conditions, focusing on more...
- Published
- 2021
15. Photocatalytic hydrogels for removal of organic contaminants from aqueous solution in continuous flow reactors
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Miguel A. Modestino, Andrea L. Quispe, Adlai Katzenberg, Nicole L. Schnabel, Akash Raman, and Andrea I. Silverman
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Fluid Flow and Transfer Processes ,chemistry.chemical_classification ,Aqueous solution ,Materials science ,Process Chemistry and Technology ,Nanoparticle ,Polymer ,Catalysis ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Chemistry (miscellaneous) ,Ionic strength ,Titanium dioxide ,Self-healing hydrogels ,Photocatalysis ,Chemical Engineering (miscellaneous) ,Degradation (geology) - Abstract
Light-driven degradation of organic contaminants by photocatalytic nanoparticles has attracted significant attention for wastewater treatment applications. However, implementation of these approaches has been limited by challenges in reactor design, which often require post-treatment separation of nanoparticles or exhibit low reactivity owing to immobilization of particles at the surface of heterogeneous supports. In this work, we present a material design strategy that circumvents these challenges by encapsulating photocatalytic particles in three-dimensional polymer networks, leading to structurally-stable photocatalytic hydrogels that were used as the walls of a flow reactor. This design leverages the volumetric reactions of commonly-implemented slurry reactors but circumvents the need for downstream separation of photocatalytic particles. A two-step soft lithography technique was used to fabricate a patterned poly(hydroxyethyl methacrylate-co-acrylic acid) hydrogel composite with embedded titanium dioxide (TiO2) nanoparticles that were employed as a photocatalyst. In this configuration, contaminant molecules introduced via a flow channel were absorbed into the hydrogel, and subsequently diffused to the surface of the embedded photocatalyst particles where they were oxidized upon light irradiation. Using reactor configurations with low residence times (15 seconds) and moderate UV irradiation (0.28 mW cm−2 at 365 nm), we demonstrated removal of up to 33% of model contaminant methylene blue (MB) and 13% of the antibiotic norfloxacin, both of which were introduced at a concentration of 3 mg L−1. The influence of molecular design parameters, such as hydrogel ionic strength, crosslinking density, and photocatalyst loading on transport and reactor performance were investigated and shown to have a strong influence on the transport properties of the hydrogels, providing options for optimizing the material to enhance treatment efficiency. more...
- Published
- 2020
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16. Comparison of biological weighting functions used to model endogenous sunlight inactivation rates of MS2 coliphage
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Andrea I. Silverman, Nikolaos Machairas, and Nerissa Tay
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Environmental Engineering ,Virus inactivation ,0208 environmental biotechnology ,Endogeny ,02 engineering and technology ,010501 environmental sciences ,Coliphages ,01 natural sciences ,Model validation ,Bacteriophage MS2 ,Coliphage ,Waste Management and Disposal ,Levivirus ,0105 earth and related environmental sciences ,Water Science and Technology ,Civil and Structural Engineering ,Sunlight ,biology ,Chemistry ,Ecological Modeling ,biology.organism_classification ,Pollution ,020801 environmental engineering ,Weighting ,Disinfection ,Virus Inactivation ,Water Microbiology ,Biological system - Abstract
Sunlight inactivation is important for disinfection of viruses in sunlit waters. As such, attempts have been made to predict the endogenous photoinactivation rate of bacteriophage MS2 using biological weighting functions, which describe microorganism sensitivity to sunlight inactivation as a function of wavelength. In this study, four biological weighting function models were compared to assess their ability to predict endogenous inactivation rates (kendo) of MS2. Previously-published and newly-collected datasets consisting of an incident irradiance spectrum (used as an input to the model) and a measured inactivation rate (kobs) were used for model validation and comparison. kendo values predicted by each model were compared with measured kobs to evaluate the ability of each biological weighting function to predict endogenous sunlight inactivation rates. A model previously developed by Mattle et al. (Env. Sci. Technol. 49, 334–342) over-predicted inactivation rates, whereas the other three models – a model from Fisher et al. (Env. Sci. Technol. 45, 9249–9255), a new model developed in this study, and a modification of the model by Mattle et al. (developed as part of this study) – were better able to estimate inactivation rates. The biological relevance of the spectral shape of each biological weighting function is discussed. more...
- Published
- 2019
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17. Interlaboratory performance and quantitative PCR data acceptance metrics for NIST SRM® 2917
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Mano Sivaganesan, Jessica R. Willis, Mohammad Karim, Akin Babatola, David Catoe, Alexandria B. Boehm, Maxwell Wilder, Hyatt Green, Aldo Lobos, Valerie J. Harwood, Stephanie Hertel, Regina Klepikow, Mondraya F. Howard, Pongpan Laksanalamai, Alexis Roundtree, Mia Mattioli, Stephanie Eytcheson, Marirosa Molina, Molly Lane, Richard Rediske, Amanda Ronan, Nishita D'Souza, Joan B. Rose, Abhilasha Shrestha, Catherine Hoar, Andrea I. Silverman, Wyatt Faulkner, Kathleen Wickman, Jason G. Kralj, Stephanie L. Servetas, Monique E. Hunter, Scott A. Jackson, and Orin C. Shanks more...
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Benchmarking ,Environmental Engineering ,Water Quality ,Ecological Modeling ,Bayes Theorem ,DNA ,Real-Time Polymerase Chain Reaction ,Pollution ,Waste Management and Disposal ,Water Science and Technology ,Civil and Structural Engineering - Abstract
Surface water quality quantitative polymerase chain reaction (qPCR) technologies are expanding from a subject of research to routine environmental and public health laboratory testing. Readily available, reliable reference material is needed to interpret qPCR measurements, particularly across laboratories. Standard Reference Material® 2917 (NIST SRM® 2917) is a DNA plasmid construct that functions with multiple water quality qPCR assays allowing for estimation of total fecal pollution and identification of key fecal sources. This study investigates SRM 2917 interlaboratory performance based on repeated measures of 12 qPCR assays by 14 laboratories (n = 1008 instrument runs). Using a Bayesian approach, single-instrument run data are combined to generate assay-specific global calibration models allowing for characterization of within- and between-lab variability. Comparable data sets generated by two additional laboratories are used to assess new SRM 2917 data acceptance metrics. SRM 2917 allows for reproducible single-instrument run calibration models across laboratories, regardless of qPCR assay. In addition, global models offer multiple data acceptance metric options that future users can employ to minimize variability, improve comparability of data across laboratories, and increase confidence in qPCR measurements. more...
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- 2022
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18. Sars-Cov-2 Wastewater Surveillance for Public Health Action: Connecting Perspectives From Wastewater Researchers and Public Health Officials During a Global Pandemic
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Andrea I. Silverman, Erin K. Lipp, Patricia A. Holden, Alexandria B. Boehm, Kyle Bibby, Jill S. McClary-Gutierrez, Greg Kester, Francis L. de los Reyes, Dominique Brossard, Daniel Gerrity, Dimitrios Katehis, Nathan LaCross, Mia C Mattioli, Perrine Marcenac, Jonathan G. Meiman, Michael Balliet, Rachel T. Noble, John F. Griffith, and Sandra L. McLellan more...
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Economic growth ,medicine.medical_specialty ,Geography ,Action (philosophy) ,Wastewater ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Public health ,Pandemic ,medicine ,other - Abstract
Wastewater surveillance for SARS-CoV-2 has garnered extensive public attention during the COVID-19 pandemic as a proposed complement to existing disease surveillance systems. Over the past year, environmental microbiology and engineering researchers have advanced methods for detection and quantification of SARS-CoV-2 viral RNA in untreated sewage and demonstrated that the trends in wastewater are correlated with trends in cases reported days to weeks later depending on the location. At the start of the pandemic, the virus was also detected in wastewater in locations prior to known cases. Despite the promise of wastewater surveillance, for these measurements to translate into useful public health tools, it is necessary to bridge the barriers between researchers and the public health responders who will ultimately use the data. Here we describe the key uses, barriers, and applicability of SARS-CoV-2 wastewater surveillance for supporting public health decisions and actions. This perspective was formed from a multidisciplinary group of environmental microbiology, engineering, wastewater, and public health experts, as well as from opinions shared during three focus group discussions with officials from ten state and local public health agencies. The key barriers to use of wastewater surveillance data identified were: (1) As a new data source, most public health agencies are not yet comfortable interpreting wastewater data; (2) Public health agencies want to see SARS-CoV-2 wastewater data in their own communities to gain confidence in its utility; (3) New institutional knowledge and increased capacity is likely needed to sustain wastewater surveillance systems; and (4) The ethics of wastewater surveillance data collection, sharing, and use are not yet established. Overall, while wastewater surveillance to assess community infections is not a new idea, by addressing these barriers, the COVID-19 pandemic may be the initiating event that turns this emerging public health tool into a sustainable nationwide surveillance system. more...
- Published
- 2021
19. Scaling of SARS-CoV-2 RNA in Settled Solids from Multiple Wastewater Treatment Plants to Compare Incidence Rates of Laboratory-Confirmed COVID-19 in Their Sewersheds
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Mhara M. Coffman, Duc J. Vugia, Nasa Sinnott-Armstrong, Alexandria B. Boehm, Samuel Dorevich, Winnie Zambrana, Lorelay M. Mendoza Grijalva, Katherine E. Graham, Laura Roldan-Hernandez, David Catoe, Marlene K. Wolfe, Andrea I. Silverman, Sooyeol Kim, Alexander T. Yu, Anand Archana, and Krista R. Wigginton more...
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0303 health sciences ,Veterinary medicine ,East coast ,Ecology ,Coronavirus disease 2019 (COVID-19) ,030306 microbiology ,Relative incidence ,Health, Toxicology and Mutagenesis ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Incidence (epidemiology) ,RNA ,010501 environmental sciences ,01 natural sciences ,Pollution ,Article ,03 medical and health sciences ,Environmental Chemistry ,Environmental science ,Sewage treatment ,Waste Management and Disposal ,U s population ,0105 earth and related environmental sciences ,Water Science and Technology - Abstract
Published and unpublished reports show that SARS-CoV-2 RNA in publicly owned treatment work (POTW) wastewater influent and solids is associated with new COVID-19 cases or incidence in associated sewersheds, but methods for comparing data collected from diverse POTWs to infer information about the relative incidence of laboratory-confirmed COVID-19 cases, and scaling to allow such comparisons, have not been previously established Here, we show that SARS-CoV-2 N1 and N2 concentrations in solids normalized by concentrations of PMMoV RNA in solids can be used to compare incidence of laboratory confirmed new COVID-19 cases across POTWs Using data collected at seven POTWs along the United States West Coast, Midwest, and East Coast serving ∼3% of the U S population (9 million people), we show that a 1 log change in N gene/PMMoV is associated with a 0 24 (range 0 19 to 0 29) log10 change in incidence of laboratory confirmed COVID-19 Scaling of N1 and N2 by PMMoV is consistent, conceptually, with a mass balance model relating SARS-CoV-2 RNA to the number of infected individuals shedding virus in their stool This information should support the application of wastewater-based epidemiology to inform the response to the COVID-19 pandemic and potentially future viral pandemics © more...
- Published
- 2021
20. Making waves: Uses of real-time, hyperlocal flood sensor data for emergency management, resiliency planning, and flood impact mitigation
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Andrea I. Silverman, Tega Brain, Brett Branco, Praneeth sai venkat Challagonda, Petra Choi, Rebecca Fischman, Kathryn Graziano, Elizabeth Hénaff, Charlie Mydlarz, Paul Rothman, and Ricardo Toledo-Crow more...
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Environmental Engineering ,Ecological Modeling ,Urbanization ,Pollution ,Waste Management and Disposal ,Floods ,Water Science and Technology ,Civil and Structural Engineering - Abstract
Flooding is expected to increase due to intensification of extreme precipitation events, sea-level rise, and urbanization. Low-cost water level sensors have the ability to fill a critical data gap on the presence, depth, and duration of street-level floods by measuring flood profiles (i.e., flood stage hydrographs) in real-time with a time interval on the order of minutes. Hyperlocal flood data collected by low-cost sensors have many use cases for a variety of stakeholders including municipal agencies, community members, and researchers. Here we outline examples of potential uses of flood sensor data before, during, and after flood events, based on dialog with stakeholders in New York City. These uses include inputs to predictive flood models, generation of real-time flood alerts for community members and emergency response teams, storm recovery assistance and cataloging of storm impacts, and informing infrastructure design and investment for long-term flood resilience project planning. more...
- Published
- 2022
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21. Engineering an Interdisciplinary Connection: Bridging Gaps between Chemical, Electrical, and Environmental Engineers
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Miguel A. Modestino, Andrea I. Silverman, and Yury Dvorkin
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Backstory ,Engineering ,Multidisciplinary ,Bridging (networking) ,business.industry ,lcsh:Q ,business ,lcsh:Science ,Construction engineering - Published
- 2020
22. Systematic Review and Meta-Analysis of the Persistence and Disinfection of Human Coronaviruses and Their Viral Surrogates in Water and Wastewater
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Andrea I. Silverman and Alexandria B. Boehm
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0303 health sciences ,2019-20 coronavirus outbreak ,Coronavirus disease 2019 (COVID-19) ,Ecology ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,viruses ,Health, Toxicology and Mutagenesis ,virus diseases ,Review ,010501 environmental sciences ,Biology ,01 natural sciences ,Virology ,Pollution ,Persistence (computer science) ,03 medical and health sciences ,Wastewater ,Meta-analysis ,Environmental Chemistry ,Waste Management and Disposal ,030304 developmental biology ,0105 earth and related environmental sciences ,Water Science and Technology - Abstract
A systematic review and meta-analysis was conducted to identify decay rate constants (k) of human coronaviruses and their viral surrogates (i.e., animal coronaviruses and the enveloped bacteriophage Phi6) in water and wastewater and disinfection rates with exposure to free chlorine and germicidal ultraviolet light (UV254). Here, 73 k were identified, with only 12 for human coronaviruses, as opposed to animal coronaviruses or Phi6. In the absence of disinfectants, k increased with temperature. Between 22 and 25 °C, mean k for coronaviruses ranged from 0.19 ± 0.06 d–1 in laboratory buffer (n = 4) to 2.9 ± 0.03 d–1 in sterilized wastewater (n = 3), which are within the ranges observed for Phi6 and nonenveloped viruses. No free chlorine or UV254 disinfection studies for coronaviruses were identified that met the systematic review inclusion criteria, although evidence from the literature suggests that coronaviruses would be inactivated if disinfectant doses recommended for nonenveloped viruses were applied. Three disinfection experiments were identified for Phi6. However, given different genome compositions and virion structures between coronaviruses and Phi6, it is not clear whether Phi6 should be used as a surrogate for evaluating free chlorine or UV254k. Therefore, there is a critical need for additional studies that specifically evaluate disinfection kinetics of coronaviruses in the aqueous environment. more...
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- 2020
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23. Simplified Process to Determine Rate Constants for Sunlight-Mediated Removal of Trace Organic and Microbial Contaminants in Unit Process Open-Water Treatment Wetlands
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Andrea I. Silverman, Kara L. Nelson, and David L. Sedlak
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geography ,geography.geographical_feature_category ,Natural water ,food and beverages ,Wetland ,02 engineering and technology ,010501 environmental sciences ,021001 nanoscience & nanotechnology ,01 natural sciences ,Pollution ,Reaction rate constant ,Open water ,Microbial contaminants ,Environmental chemistry ,Scientific method ,Constructed wetland ,Environmental Chemistry ,Environmental science ,0210 nano-technology ,Waste Management and Disposal ,Unit process ,0105 earth and related environmental sciences - Abstract
Unit process, open-water (UPOW) treatment wetlands are a unique type of constructed wetlands that are designed to promote photo- and microbiologically mediated natural water treatment proc...
- Published
- 2019
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24. Correction for 'Scaling of SARS-CoV-2 RNA in Settled Solids from Multiple Wastewater Treatment Plants to Compare Incidence Rates of Laboratory-Confirmed COVID-19 in Their Sewersheds'
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Katherine E. Graham, Laura Roldan-Hernandez, David Catoe, Marlene K. Wolfe, Lorelay M. Mendoza Grijalva, Andrea I. Silverman, S. Dorevitch, Alexander T. Yu, Anand Archana, W. Zambrana, Alexandria B. Boehm, Krista R. Wigginton, Mhara M. Coffman, Duc J. Vugia, Nasa Sinnott-Armstrong, and Sooyeol Kim more...
- Subjects
2019-20 coronavirus outbreak ,Ecology ,Coronavirus disease 2019 (COVID-19) ,Health, Toxicology and Mutagenesis ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Environmental Chemistry ,RNA ,Sewage treatment ,Pollution ,Waste Management and Disposal ,Virology ,Water Science and Technology ,Chemical society - Abstract
The name of author Samuel Dorevitch was mispelled in the original paper. © 2021 American Chemical Society. All rights reserved.
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- 2021
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25. Global Sensitivity Analysis of Environmental, Water Quality, Photoreactivity, and Engineering Design Parameters in Sunlight Inactivation of Viruses
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Jeremy S. Guest, Amanda Lardizabal, Andrea I. Silverman, Tamar Kohn, Xinyi Zhang, Thanh H. Nguyen, and Davide Vione
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Sunlight ,Total organic carbon ,Hydraulic retention time ,Microorganism ,Bacteriophage phi X 174 ,Humans ,Levivirus ,Ponds ,Water Quality ,General Chemistry ,010501 environmental sciences ,Solar irradiance ,01 natural sciences ,Wastewater ,Global sensitivity analysis ,Environmental chemistry ,Environmental Chemistry ,Environmental science ,Water quality ,0105 earth and related environmental sciences - Abstract
Sunlight-mediated inactivation of microorganisms is a low-cost approach to disinfect drinking water and wastewater. The reactions involved are affected by a wide range of factors, and a lack of knowledge about their relative importance makes it challenging to optimize treatment systems. To characterize the relative importance of environmental conditions, photoreactivity, water quality, and engineering design in the sunlight inactivation of viruses, we modeled the inactivation of three-human adenovirus and two bacteriophages-MS2 and phiX174-in surface waters and waste stabilization ponds by integrating solar irradiance and aquatic photochemistry models under uncertainty. Through global sensitivity analyses, we quantitatively apportioned the variability of predicted sunlight inactivation rate constants to different factors. Most variance was associated with the variability in and interactions among time, location, nonpurgeable organic carbon (NPOC) concentration, and pond depth. The photolysis quantum yield of the virus outweighed the seasonal solar motion in the impact on inactivation rates. Further, comparison of simulated sunlight inactivation efficacy in maturation ponds under different design decisions showed that reducing pond depth can increase the log inactivation at the cost of larger land area, but increasing hydraulic retention time by adding ponds in series yielded greater improvements in inactivation. more...
- Published
- 2020
26. Systematic review and meta-analysis of decay rates of waterborne mammalian viruses and coliphages in surface waters
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Andrea I. Silverman, Alexandria B. Boehm, Kelly D. Goodwin, and Alexander Schriewer
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Rotavirus ,Environmental Engineering ,viruses ,0208 environmental biotechnology ,Zoology ,02 engineering and technology ,010501 environmental sciences ,Biology ,medicine.disease_cause ,01 natural sciences ,Coliphages ,Virus ,Astrovirus ,medicine ,Animals ,Humans ,Coliphage ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Water Science and Technology ,Civil and Structural Engineering ,Enterovirus ,Pollutant ,Ecological Modeling ,Infectious dose ,virus diseases ,biology.organism_classification ,Pollution ,020801 environmental engineering ,Viruses ,Norovirus ,Water Microbiology ,Norwalk virus ,Surface water - Abstract
Surface waters are essential natural resources. They are also receiving waters for a variety of anthropogenic waste streams that carry a myriad of pollutants including pathogens. Watershed and fate and transport models can help inform the spatial and temporal extent of microbial pollution from point and non-point sources and thus provide useful information for managing surface waters. Viruses are particularly important water-related pathogens because they often have a low infectious dose, which means that ingestion of even a small volume of water containing a low concentration of virions has the potential to cause disease. We conducted a systematic review of the literature, following best practices, to gather decay rate constants (k) of mammalian waterborne viruses (enteroviruses, adenoviruses, noroviruses, astroviruses, rotaviruses, and hepatitis A viruses) and coliphages in raw surface waters to aid in the parameterization of virus fate and transport models. We identified 562 k values from the literature, with the largest number identified for enteroviruses and coliphages and the smallest for astrovirus, hepatitis A virus, and norovirus. Average k values for each virus varied from 0.07 to 0.9 per day, in order from smallest to largest: Norwalk virus (i.e., noroviruses) Human astrovirus Mastadenovirus (i.e., adenoviruses) Hepatovirus A (i.e., hepatitis A viruses) Rotavirus A coliphages Enterovirus. A meta-analysis investigated how k varied among viruses for experiments conducted with different virus serotypes or species at different temperatures, salinities, and sunlight exposures, and for experiments that enumerated viruses using different methodologies. Virus species or serotype did not affect k among decay experiments. k values were generally larger for experiments conducted at higher temperatures, in sunlight, and in estuarine waters, and enumerated using culture methods. k values were statistically different between virus types with Norwalk virus, Hepatovirus A, and Mastadenovirus having smaller k values than other viruses, controlling for experimental condition and enumeration method. While F+ coliphage k values were similar to those of Enterovirus, Human astrovirus, and Rotavirus A, they were different from those of the other mammalian viruses. This compilation of coliphage and mammalian virus k values provides essential information for researchers and risk assessors who model virus fate and transport in surface waters and identifies avenues for future research to fill knowledge gaps. more...
- Published
- 2019
27. Sunlight-mediated inactivation of health-relevant microorganisms in water: a review of mechanisms and modeling approaches
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Tamar Kohn, Roberto A. Rodriguez, Kimberly M. Parker, Peter A. Maraccini, Kara L. Nelson, William A. Mitch, Karl G. Linden, Richard G. Zepp, Robert J. Davies-Colley, Kristopher McNeill, Krista R. Wigginton, Yuanyuan Liu, Michael C. Dodd, Thanh H. Nguyen, Alexandria B. Boehm, Lauren M. Sassoubre, and Andrea I. Silverman more...
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0301 basic medicine ,Sunlight ,Bacteria ,integumentary system ,Photochemistry ,Microorganism ,030106 microbiology ,Public Health, Environmental and Occupational Health ,Natural surface ,food and beverages ,General Medicine ,Models, Theoretical ,Management, Monitoring, Policy and Law ,Article ,6. Clean water ,Natural organic matter ,03 medical and health sciences ,13. Climate action ,Viruses ,Recreational water quality ,Biophysics ,Environmental Chemistry ,Water Microbiology ,Organism - Abstract
Health-relevant microorganisms present in natural surface waters and engineered treatment systems that are exposed to sunlight can be inactivated by a complex set of interacting mechanisms. The net impact of sunlight depends on the solar spectral irradiance, the susceptibility of the specific microorganism to each mechanism, and the water quality; inactivation rates can vary by orders of magnitude depending on the organism and environmental conditions. Natural organic matter (NOM) has a large influence, as it can attenuate radiation and thus decrease inactivation by endogenous mechanisms. Simultaneously NOM sensitizes the formation of reactive intermediates that can damage microorganisms via exogenous mechanisms. To accurately predict inactivation and design engineered systems that enhance solar inactivation, it is necessary to model these processes, although some details are not yet sufficiently well understood. In this critical review, we summarize the photo-physics, -chemistry, and -biology that underpin sunlight-mediated inactivation, as well as the targets of damage and cellular responses to sunlight exposure. Viruses that are not susceptible to exogenous inactivation are only inactivated if UVB wavelengths (280–320 nm) are present, such as in very clear, open waters or in containers that are transparent to UVB. Bacteria are susceptible to slightly longer wavelengths. Some viruses and bacteria (especially Gram-positive) are susceptible to exogenous inactivation, which can be initiated by visible as well as UV wavelengths. We review approaches to model sunlight-mediated inactivation and illustrate how the environmental conditions can dramatically shift the inactivation rate of organisms. The implications of this mechanistic understanding of solar inactivation are discussed for a range of applications, including recreational water quality, natural treatment systems, solar disinfection of drinking water (SODIS), and enhanced inactivation via the use of sensitizers and photocatalysts. Finally, priorities for future research are identified that will further our understanding of the key role that sunlight disinfection plays in natural systems and the potential to enhance this process in engineered systems. ISSN:2050-7887 ISSN:2050-7895 more...
- Published
- 2018
28. On-farm treatment of wastewater used for vegetable irrigation: bacteria and virus removal in small ponds in Accra, Ghana
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Andrea I. Silverman, M. O. Akrong, Kara L. Nelson, and Pay Drechsel
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Irrigation ,biology ,Sedimentation (water treatment) ,fungi ,Environmental engineering ,Indicator bacteria ,Filtration and Separation ,STREAMS ,Contamination ,biology.organism_classification ,Wastewater ,Environmental science ,Coliphage ,Bacteria ,Water Science and Technology - Abstract
Many urban farmers in Accra collect irrigation water from streams and open drains, which they store in small, on-farm ponds before use. Given that this water can be highly contaminated with wastewater, another potential role of the ponds is to disinfect irrigation water prior to use. To better understand the factors influencing bacteria and virus removal in these small ponds, we investigated the removal of culturable fecal indicator bacteria (Escherichia coli and enterococci) and coliphage (F+ and somatic coliphage) in a single batch of water stored for 3 days. Sunlight exposure was found to be important for removal. Bacteria and coliphage removal rates were faster in shallow sun-exposed water than in deeper water, due to sunlight attenuation with depth. Bacteria removal rates varied depending on solar irradiation, and correlations between total daily UVB fluence and bacteria removal rates were observed. Coliphage removal was observed in sun-exposed water but not in dark controls that allowed for sedimentation, further highlighting the importance of sunlight-mediated processes. These small ponds appear to have similar disinfection processes to larger-scale waste stabilization ponds, but can have more efficient inactivation due to their shallow depth and operation as batch reactors. Design and management recommendations for on-farm ponds are discussed. more...
- Published
- 2014
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29. Sunlight Inactivation of MS2 Coliphage in the Absence of Photosensitizers: Modeling the Endogenous Inactivation Rate Using a Photoaction Spectrum
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Kara L. Nelson, Mi T. Nguyen, and Andrea I. Silverman
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Sunlight ,Photosensitizing Agents ,Time Factors ,Meteorology ,Irradiance ,Endogeny ,General Chemistry ,Models, Theoretical ,Biology ,Solar irradiance ,biology.organism_classification ,Biophysics ,Virus Inactivation ,Environmental Chemistry ,Coliphage ,Seasons ,sense organs ,Water Microbiology ,skin and connective tissue diseases ,Levivirus ,Action spectrum - Abstract
The endogenous sunlight inactivation rates of MS2 coliphage in photosensitizer-free water were measured (kobs) under different light conditions and compared to modeled inactivation rates (kmod) computed using a previously published action spectrum. Experiments were conducted under simulated and natural sunlight. There was generally good agreement between modeled and observed MS2 sunlight inactivation rates in the summer and winter, suggesting that the action spectrum can be used to predict changes in the inactivation rate caused by diurnal and seasonal changes in natural sunlight irradiance. However, we show that a major source of uncertainty in the predictions is the ability to accurately measure or model the comparatively weak and highly variable solar irradiance between 280 and 300 nm, a range to which the inactivation rate is very sensitive. The action spectrum was also used to predict the endogenous inactivation rates of MS2 at different depths in a column of strongly humic-colored [i.e., solar ultraviolet (UV)-attenuating] wetland water under simulated sunlight; we observed fairly good agreement between kobs and kmod, suggesting that the action spectrum can be used to estimate the decrease in the endogenous inactivation rate caused by spectrally selective sunlight attenuation in the water column. more...
- Published
- 2014
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30. Quantification of human norovirus GII, human adenovirus, and fecal indicator organisms in wastewater used for irrigation in Accra, Ghana
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Andrea I. Silverman, M. O. Akrong, Kara L. Nelson, Pay Drechsel, and Philip Amoah
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Microbiology (medical) ,Veterinary medicine ,Agricultural Irrigation ,Stabilization pond ,Colony Count, Microbial ,Indicator bacteria ,Guidelines as Topic ,Wastewater ,Real-Time Polymerase Chain Reaction ,World Health Organization ,medicine.disease_cause ,Ghana ,Risk Assessment ,Microbiology ,Feces ,medicine ,Humans ,Waste Management and Disposal ,Water Science and Technology ,Indicator organism ,Bacteria ,biology ,Adenoviruses, Human ,Norovirus ,Public Health, Environmental and Occupational Health ,biology.organism_classification ,Bacteroidales ,Fecal coliform ,Infectious Diseases ,Sewage treatment ,Water Microbiology ,Environmental Monitoring - Abstract
Quantitative microbial risk assessment (QMRA) is frequently used to estimate health risks associated with wastewater irrigation and requires pathogen concentration estimates as inputs. However, human pathogens, such as viruses, are rarely quantified in water samples, and simple relationships between fecal indicator bacteria and pathogen concentrations are used instead. To provide data that can be used to refine QMRA models of wastewater-fed agriculture in Accra, stream, drain, and waste stabilization pond waters used for irrigation were sampled and analyzed for concentrations of fecal indicator microorganisms (human-specific Bacteroidales, Escherichia coli, enterococci, thermotolerant coliform, and somatic and F+ coliphages) and two human viruses (adenovirus and norovirus genogroup II). E. coli concentrations in all samples exceeded limits suggested by the World Health Organization, and human-specific Bacteroidales was found in all but one sample, suggesting human fecal contamination. Human viruses were detected in 16 out of 20 samples, were quantified in 12, and contained 2–3 orders of magnitude more norovirus than predicted by norovirus to E. coli concentration ratios assumed in recent publications employing indicator-based QMRA. As wastewater irrigation can be beneficial for farmers and municipalities, these results should not discourage water reuse in agriculture, but provide motivation and targets for wastewater treatment before use on farms. more...
- Published
- 2013
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31. Modeling the Endogenous Sunlight Inactivation Rates of Laboratory Strain and Wastewater E. coli and Enterococci Using Biological Weighting Functions
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Andrea I. Silverman and Kara L. Nelson
- Subjects
0301 basic medicine ,Sunlight ,Strain (chemistry) ,biology ,030106 microbiology ,Environmental engineering ,General Chemistry ,Numerical models ,Wastewater ,biology.organism_classification ,Disinfection ,03 medical and health sciences ,Environmental chemistry ,Escherichia coli ,Environmental Chemistry ,Sewage treatment ,Water Microbiology ,Bacteria ,Enterococcus - Abstract
Models that predict sunlight inactivation rates of bacteria are valuable tools for predicting the fate of pathogens in recreational waters and designing natural wastewater treatment systems to meet disinfection goals. We developed biological weighting function (BWF)-based numerical models to estimate the endogenous sunlight inactivation rates of E. coli and enterococci. BWF-based models allow the prediction of inactivation rates under a range of environmental conditions that shift the magnitude or spectral distribution of sunlight irradiance (e.g., different times, latitudes, water absorbances, depth). Separate models were developed for laboratory strain bacteria cultured in the laboratory and indigenous organisms concentrated directly from wastewater. Wastewater bacteria were found to be 5-7 times less susceptible to full-spectrum simulated sunlight than the laboratory bacteria, highlighting the importance of conducting experiments with bacteria sourced directly from wastewater. The inactivation rate models fit experimental data well and were successful in predicting the inactivation rates of wastewater E. coli and enterococci measured in clear marine water by researchers from a different laboratory. Additional research is recommended to develop strategies to account for the effects of elevated water pH on predicted inactivation rates. more...
- Published
- 2016
32. Comparison of enterovirus and adenovirus concentration and enumeration methods in seawater from Southern California, USA and Baja Malibu, Mexico
- Author
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Alexandria B. Boehm, Andrea I. Silverman, David C. Love, Lauren M. Sassoubre, and Kara L. Nelson
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Microbiology (medical) ,food.ingredient ,Biology ,medicine.disease_cause ,California ,Adenoviridae ,law.invention ,Microbiology ,food ,law ,Skimmed milk ,medicine ,Humans ,Seawater ,Mexico ,Waste Management and Disposal ,Polymerase chain reaction ,Enterovirus ,Water Science and Technology ,Infectivity ,Bacteriological Techniques ,Reverse Transcriptase Polymerase Chain Reaction ,Public Health, Environmental and Occupational Health ,Reverse transcriptase ,Reverse transcription polymerase chain reaction ,Infectious Diseases ,Water quality ,Water Microbiology ,Cell culture assays - Abstract
Despite being important etiological agents of waterborne illness, the sources, transport and decay of human viruses in recreational waters are not well understood. This study examines enterovirus and adenovirus concentrations in coastal water samples collected from four beaches impacted by microbial pollution: (1) Malibu Lagoon, Malibu; (2) Tijuana River, Imperial Beach; (3) Baja Malibu, Baja California; and (4) Punta Bandera, Baja California. Water samples were concentrated using a flocculation-based skim milk method and dead-end membrane filtration (MF). Viruses were enumerated using cell culture infectivity assays and reverse transcription quantitative polymerase chain reaction (RT-QPCR). Across concentration and quantification methods, enteroviruses were detected more often than adenoviruses. For both viruses, MF followed by (RT)QPCR yielded higher concentrations than skim milk flocculation followed by (RT)QPCR or cell culture assays. Samples concentrated by skim milk flocculation and enumerated by (RT)QPCR agreed more closely with concentrations enumerated by cell culture assays than MF followed by (RT)QPCR. The detection of viruses by MF and (RT)QPCR was positively correlated with the presence of infectious viruses. Further research is needed to determine if detection of viruses by rapid methods such as (RT)QPCR can be a useful water quality monitoring tool to assess health risks in recreational waters. more...
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- 2012
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33. Human Virus and Bacteriophage Inactivation in Clear Water by Simulated Sunlight Compared to Bacteriophage Inactivation at a Southern California Beach
- Author
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Andrea I. Silverman, Kara L. Nelson, and David C. Love
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Virus Cultivation ,food.ingredient ,Ultraviolet Rays ,viruses ,Buffers ,medicine.disease_cause ,Coliphages ,Bathing Beaches ,California ,Microbiology ,Bacteriophage ,food ,Bacteriophage MS2 ,medicine ,Humans ,Environmental Chemistry ,Agar ,Bacteriophages ,Seawater ,Coliphage ,Sunlight ,biology ,General Chemistry ,Reference Standards ,biology.organism_classification ,Saline water ,Kinetics ,Virus Inactivation ,Enterovirus ,Solar simulator ,Water Microbiology - Abstract
Few quantitative data exist on human virus inactivation by sunlight and the relationship between human and indicator viruses under sunlit conditions. We investigated the effects of sunlight on human viruses (adenovirus type 2, poliovirus type 3) and bacteriophages (MS2, Q-Beta SP, Fi, M13, PRD1, Phi-X174, and coliphages isolated from Avalon Bay, California). Viruses were inoculated into phosphate buffered saline or seawater, exposed to a laboratory solar simulator for ≤12 h, and enumerated by double agar layer or cell culture to derive first-order inactivation rate constants (k(obs), h(-1)). The viruses most resistant to sunlight were adenovirus type 2 (k(obs)= 0.59 ± 0.04 h(-1)) and bacteriophage MS2 (k(obs)= 0.43 ± 0.02 h(-1)), which suggests MS2 may be a conservative indicator for sunlight resistant human viruses in clear water when sunlight inactivation is the main removal mechanism. Reasonable agreement was observed between somatic coliphage inactivation rates measured in the solar simulator (k(mean) = 1.81 h(-1)) and somatic coliphages measured in the surf zone during a field campaign at Avalon Bay during similar sunlight intensity (k = 0.75 h(-1) at log-RMSE minimum; k(range) = 0.54 h(-1) to >1.88 h(-1); Boehm, A. B. et al. Environ. Sci. Technol. 2009, 43, (21), 8046-8052). Hence, measuring sunlight inactivation rates of viruses in the laboratory can be used to estimate inactivation in the environment under similar sunlight and water quality conditions. more...
- Published
- 2010
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34. Sunlight Inactivation of Viruses in Open-Water Unit Process Treatment Wetlands: Modeling Endogenous and Exogenous Inactivation Rates
- Author
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Andrea I. Silverman, Kara L. Nelson, Mi T. Nguyen, Iris E. Schilling, and Jannis Wenk
- Subjects
Sunlight ,geography ,geography.geographical_feature_category ,Ultraviolet Rays ,viruses ,Environmental engineering ,food and beverages ,Endogeny ,Wetland ,General Chemistry ,Biology ,Wastewater ,Models, Biological ,Water Purification ,Open water ,SDG 3 - Good Health and Well-being ,Viruses ,Biophysics ,Environmental Chemistry ,Virus Inactivation ,Poliovirus type - Abstract
Sunlight inactivation is an important mode of disinfection for viruses in surface waters. In constructed wetlands, for example, open-water cells can be used to promote sunlight disinfection and remove pathogenic viruses from wastewater. To aid in the design of these systems, we developed predictive models of virus attenuation that account for endogenous and exogenous sunlight-mediated inactivation mechanisms. Inactivation rate models were developed for two viruses, MS2 and poliovirus type 3; laboratory- and field-scale experiments were conducted to evaluate the models' ability to estimate inactivation rates in a pilot-scale, open-water, unit-process wetland cell. Endogenous inactivation rates were modeled using either photoaction spectra or total, incident UVB irradiance. Exogenous inactivation rates were modeled on the basis of virus susceptibilities to singlet oxygen. Results from both laboratory- and field-scale experiments showed good agreement between measured and modeled inactivation rates. The modeling approach presented here can be applied to any sunlit surface water and utilizes easily measured inputs such as depth, solar irradiance, water matrix absorbance, singlet oxygen concentration, and the virus-specific apparent second-order rate constant with singlet oxygen (k2). Interestingly, the MS2 k2 in the open-water wetland was found to be significantly larger than k2 observed in other waters in previous studies. Examples of how the model can be used to design and optimize natural treatment systems for virus inactivation are provided. more...
- Published
- 2015
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35. Sunlight inactivation of human viruses and bacteriophages in coastal waters containing natural photosensitizers
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Alexandria B. Boehm, Britt M. Peterson, Kristopher McNeill, Andrea I. Silverman, and Kara L. Nelson
- Subjects
Sunlight ,Salinity ,biology ,viruses ,Natural water ,General Chemistry ,Hydrogen-Ion Concentration ,biology.organism_classification ,Virology ,Adenoviridae ,Bacteriophage ,Oxygen ,Poliovirus ,Water matrix ,Environmental chemistry ,Environmental Chemistry ,Humans ,Bacteriophage PRD1 ,Poliovirus type ,Water Microbiology ,Surface water ,Levivirus - Abstract
Sunlight inactivation of poliovirus type 3 (PV3), adenovirus type 2 (HAdV2), and two bacteriophage (MS2 and PRD1) was investigated in an array of coastal waters to better understand solar inactivation mechanisms and the effect of natural water constituents on observed inactivation rates (k(obs)). Reactor scale inactivation experiments were conducted using a solar simulator, and k(obs) for each virus was measured in a sensitizer-free control and five unfiltered surface water samples collected from different sources. k(obs) values varied between viruses in the same water matrix, and for each virus in different matrices, with PV3 having the fastest and MS2 the slowest k(obs) in all waters. When exposed to full-spectrum sunlight, the presence of photosensitizers increased k(obs) of HAdV2, PRD1 and MS2, but not PV3, which provides evidence that the exogenous sunlight inactivation mechanism, involving damage by exogenously produced reactive intermediates, played a greater role for these viruses. While PV3 inactivation was observed to be dominated by endogenous mechanisms, this may be due to a masking of exogenous k(obs) by significantly faster endogenous k(obs). Results illustrate that differences in water composition can shift absolute and relative inactivation rates of viruses, which has important implications for natural wastewater treatment systems, solar disinfection (SODIS), and the use of indicator organisms for monitoring water quality. more...
- Published
- 2013
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