Ronald W Harvey (Former Employee)
Science and Products
Filter Total Items: 80
What makes a natural clay antibacterial? What makes a natural clay antibacterial?
Natural clays have been used in ancient and modern medicine, but the mechanism(s) that make certain clays lethal against bacterial pathogens has not been identified. We have compared the depositional environments, mineralogies, and chemistries of clays that exhibit antibacterial effects on a broad spectrum of human pathogens including antibiotic resistant strains. Natural antibacterial...
Authors
Lynda B. Williams, David W. Metge, Dennis D. Eberl, Ronald W. Harvey, Amanda G. Turner, Panjai Prapaipong, Amisha T. Port-Peterson
Effects of the antimicrobial sulfamethoxazole on groundwater bacterial enrichment Effects of the antimicrobial sulfamethoxazole on groundwater bacterial enrichment
The effects of “trace” (environmentally relevant) concentrations of the antimicrobial agent sulfamethoxazole (SMX) on the growth, nitrate reduction activity, and bacterial composition of an enrichment culture prepared with groundwater from a pristine zone of a sandy drinking-water aquifer on Cape Cod, MA, were assessed by laboratory incubations. When the enrichments were grown under...
Authors
Jennifer C. Underwood, Ronald W. Harvey, David W. Metge, Deborah A. Repert, Laura K. Baumgartner, Richard L. Smith, Timberly M. Roane, Larry B. Barber
Differential effects of dissolved organic carbon upon re-entrainment and surface properties of groundwater bacteria and bacteria-sized microspheres during transport through a contaminated, sandy aquifer Differential effects of dissolved organic carbon upon re-entrainment and surface properties of groundwater bacteria and bacteria-sized microspheres during transport through a contaminated, sandy aquifer
Injection-and-recovery studies involving a contaminated, sandy aquifer (Cape Cod, Massachusetts) were conducted to assess the relative susceptibility for in situ re-entrainment of attached groundwater bacteria (Pseudomonas stuzeri ML2, and uncultured, native bacteria) and carboxylate-modified microspheres (0.2 and 1.0 μm diameters). Different patterns of re-entrainment were evident for...
Authors
Ronald W. Harvey, D.W. Metge, A. Mohanram, X. Gao, J. Chorover
Fluorescent microspheres as surrogates in evaluating the efficacy of riverbank filtration for removing Cryptosporidium parvum oocysts and other pathogens Fluorescent microspheres as surrogates in evaluating the efficacy of riverbank filtration for removing Cryptosporidium parvum oocysts and other pathogens
A major benefit of riverbank filtration (RBF) is that it provides a relatively effective means for pathogen removal. There is a need to conduct more injection-and-recovery transport studies at operating RBF sites in order to properly assess the combined effects of the site heterogeneities and ambient physicochemical conditions, which are difficult to replicate in the lab. For field...
Authors
Ronald W. Harvey, David W. Metge, Rodney A. Sheets, Jay Jasperse
Effects of sediment-associated extractable metals, degree of sediment grain sorting, and dissolved organic carbon upon Cryptosporidium parvum removal and transport within riverbank filtration sediments, Sonoma County, California Effects of sediment-associated extractable metals, degree of sediment grain sorting, and dissolved organic carbon upon Cryptosporidium parvum removal and transport within riverbank filtration sediments, Sonoma County, California
Oocysts of the protozoan pathogen Cryptosporidium parvum are of particular concern for riverbank filtration (RBF) operations because of their persistence, ubiquity, and resistance to chlorine disinfection. At the Russian River RBF site (Sonoma County, CA), transport of C. parvumoocysts and oocyst-sized (3 μm) carboxylate-modified microspheres through poorly sorted (sorting indices, σ1...
Authors
D.W. Metge, R.W. Harvey, G. R. Aiken, R. Anders, G. Lincoln, James Jasperse, M. C. Hill
Effects of altered groundwater chemistry upon the pH-dependency and magnitude of bacterial attachment during transport within an organically contaminated sandy aquifer Effects of altered groundwater chemistry upon the pH-dependency and magnitude of bacterial attachment during transport within an organically contaminated sandy aquifer
The effects of a dilute (ionic strength = 5 × 10−3 M) plume of treated sewage, with elevated levels (3.9 mg/L) of dissolved organic carbon (DOC), upon the pH-dependency and magnitude of bacterial transport through an iron-laden, quartz sand aquifer (Cape Cod, MA) were evaluated using sets of replicate, static minicolumns. Compared with uncontaminated groundwater, the plume chemistry...
Authors
Ronald W. Harvey, David W. Metge, Larry B. Barber, George R. Aiken
Science and Products
Filter Total Items: 80
What makes a natural clay antibacterial? What makes a natural clay antibacterial?
Natural clays have been used in ancient and modern medicine, but the mechanism(s) that make certain clays lethal against bacterial pathogens has not been identified. We have compared the depositional environments, mineralogies, and chemistries of clays that exhibit antibacterial effects on a broad spectrum of human pathogens including antibiotic resistant strains. Natural antibacterial...
Authors
Lynda B. Williams, David W. Metge, Dennis D. Eberl, Ronald W. Harvey, Amanda G. Turner, Panjai Prapaipong, Amisha T. Port-Peterson
Effects of the antimicrobial sulfamethoxazole on groundwater bacterial enrichment Effects of the antimicrobial sulfamethoxazole on groundwater bacterial enrichment
The effects of “trace” (environmentally relevant) concentrations of the antimicrobial agent sulfamethoxazole (SMX) on the growth, nitrate reduction activity, and bacterial composition of an enrichment culture prepared with groundwater from a pristine zone of a sandy drinking-water aquifer on Cape Cod, MA, were assessed by laboratory incubations. When the enrichments were grown under...
Authors
Jennifer C. Underwood, Ronald W. Harvey, David W. Metge, Deborah A. Repert, Laura K. Baumgartner, Richard L. Smith, Timberly M. Roane, Larry B. Barber
Differential effects of dissolved organic carbon upon re-entrainment and surface properties of groundwater bacteria and bacteria-sized microspheres during transport through a contaminated, sandy aquifer Differential effects of dissolved organic carbon upon re-entrainment and surface properties of groundwater bacteria and bacteria-sized microspheres during transport through a contaminated, sandy aquifer
Injection-and-recovery studies involving a contaminated, sandy aquifer (Cape Cod, Massachusetts) were conducted to assess the relative susceptibility for in situ re-entrainment of attached groundwater bacteria (Pseudomonas stuzeri ML2, and uncultured, native bacteria) and carboxylate-modified microspheres (0.2 and 1.0 μm diameters). Different patterns of re-entrainment were evident for...
Authors
Ronald W. Harvey, D.W. Metge, A. Mohanram, X. Gao, J. Chorover
Fluorescent microspheres as surrogates in evaluating the efficacy of riverbank filtration for removing Cryptosporidium parvum oocysts and other pathogens Fluorescent microspheres as surrogates in evaluating the efficacy of riverbank filtration for removing Cryptosporidium parvum oocysts and other pathogens
A major benefit of riverbank filtration (RBF) is that it provides a relatively effective means for pathogen removal. There is a need to conduct more injection-and-recovery transport studies at operating RBF sites in order to properly assess the combined effects of the site heterogeneities and ambient physicochemical conditions, which are difficult to replicate in the lab. For field...
Authors
Ronald W. Harvey, David W. Metge, Rodney A. Sheets, Jay Jasperse
Effects of sediment-associated extractable metals, degree of sediment grain sorting, and dissolved organic carbon upon Cryptosporidium parvum removal and transport within riverbank filtration sediments, Sonoma County, California Effects of sediment-associated extractable metals, degree of sediment grain sorting, and dissolved organic carbon upon Cryptosporidium parvum removal and transport within riverbank filtration sediments, Sonoma County, California
Oocysts of the protozoan pathogen Cryptosporidium parvum are of particular concern for riverbank filtration (RBF) operations because of their persistence, ubiquity, and resistance to chlorine disinfection. At the Russian River RBF site (Sonoma County, CA), transport of C. parvumoocysts and oocyst-sized (3 μm) carboxylate-modified microspheres through poorly sorted (sorting indices, σ1...
Authors
D.W. Metge, R.W. Harvey, G. R. Aiken, R. Anders, G. Lincoln, James Jasperse, M. C. Hill
Effects of altered groundwater chemistry upon the pH-dependency and magnitude of bacterial attachment during transport within an organically contaminated sandy aquifer Effects of altered groundwater chemistry upon the pH-dependency and magnitude of bacterial attachment during transport within an organically contaminated sandy aquifer
The effects of a dilute (ionic strength = 5 × 10−3 M) plume of treated sewage, with elevated levels (3.9 mg/L) of dissolved organic carbon (DOC), upon the pH-dependency and magnitude of bacterial transport through an iron-laden, quartz sand aquifer (Cape Cod, MA) were evaluated using sets of replicate, static minicolumns. Compared with uncontaminated groundwater, the plume chemistry...
Authors
Ronald W. Harvey, David W. Metge, Larry B. Barber, George R. Aiken