Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
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Effects of physical and chemical heterogeneity on water-quality samples obtained from wells
Factors that affect the mass of chemical constituents entering a well include the distributions of flow rate and chemical concentrations along and near the screened or open section of the well. Assuming a layered porous medium (with each layer being characterized by a uniform hydraulic conductivity and chemical concentration), a knowledge of the flow from each layer along the screened zone and of
Authors
Thomas E. Reilly, Jacob Gibs
A Fast Fourier transform stochastic analysis of the contaminant transport problem
A three-dimensional stochastic analysis of the contaminant transport problem is developed in the spirit of Naff (1990). The new derivation is more general and simpler than previous analysis. The fast Fourier transformation is used extensively to obtain numerical estimates of the mean concentration and various spatial moments. Data from both the Borden and Cape Cod experiments are used to test the
Authors
F.W. Deng, J.H. Cushman, J.W. Delleur
Degradation of trichloroethylene by Pseudomonas cepacia G4 and the constitutive mutant strain G4 5223 PR1 in aquifer microcosms
Pseudomonas cepacia G4 degrades trichloroethylene (TCE) via a degradation pathway for aromatic compounds which is induced by substrates such as phenol and tryptophan. P. cepacia G4 5223 PR1 (PR1) is a Tn5 insertion mutant which constitutively expresses the toluene ortho-monooxygenase responsible for TCE degradation. In groundwater microcosms, phenol-induced strain G4 and noninduced strain PR1 degr
Authors
M.L. Krumme, K.N. Timmis, D.F. Dwyer
Effect of pH on bacteriophage transport through sandy soils
Effects of pH and hydrophobicity on attachment and detachment of PRD-1 and MS-2 in three different sandy soils were investigated in a series of laboratory-column experiments. Concentrations of the lipid-containing phage PRD-1 decreased 3–4 orders of magnitude during passage through the 10–15-cm-long columns. Attachment of the lipid-containing phage PRD-1 was insensitive to pH and was apparently co
Authors
Takashi Kinoshita, Roger C. Bales, Kimberley M. Maguire, Charles P. Gerba
Role of physical heterogeneity in the interpretation of small-scale laboratory and field observations of bacteria, microbial-sized microsphere, and bromide transport through aquifer sediments
The effect of physical variability upon the relative transport behavior of microbial-sized microspheres, indigenous bacteria, and bromide was examined in field and flow-through column studies for a layered, but relatively well sorted, sandy glaciofluvial aquifer. These investigations involved repacked, sieved, and undisturbed aquifer sediments. In the field, peak abundance of labeled bacteria trav
Authors
Ronald W. Harvey, Nancy E. Kinner, Dan MacDonald, David W. Metge, Amoret Bunn
Determination of size and element composition distributions of complex colloids by sedimentation field-flow fractionation—inductively coupled plasma mass spectrometry
Sedimentation field-flow fractionation (SdFFF) and inductively coupled plasma mass spectrometry (ICP-MS) have been directly combined and the resulting SdFFF-ICP-MS instrument can be used to produce element based size distributions of colloidal samples. Using appropriate tracer elements the size distributions of specific components can be picked out from a complex mixture. Changes in chemical compo
Authors
Deirdre M. Murphy, John R. Garbarino, Howard E. Taylor, Ronald Beckett, B. Hart
A pressure-packer system for conducting rising head tests in water table wells
The pressure system developed for fully-saturated well screens has been modified for conducting rising head tests in water table wells installed in highly permeable aquifers. The pressure system consists of a compressed air source and 1 inch diameter PVC piping with a packer attached at the end. The pressure system was evaluated in a series of rising head tests conducted in a well at a Superfund s
Authors
Benjamin S. Levy, Lawrence J. Pannell, John P. Dadoly
Groundwater as a nonpoint source of atrazine and deethylatrazine in a river during base flow conditions
Alluvial groundwater adjacent to the main stem river is the principal nonpoint source of atrazine and deethylatrazine in the Cedar River of Iowa after the river has been in base flow conditions for 5 days. Between two sites along a 116-km reach of the Cedar River, tributaries contributed about 25% of the increase in the atrazine and deethylatrazine load, whereas groundwater from the alluvial aquif
Authors
Paul J. Squillace, E.M. Thurman, Edward T. Furlong
Surface chemical effects on colloid stability and transport through natural porous media
Surface chemical effects on colloidal stability and transport through porous media were investigated using laboratory column techniques. Approximately 100 nm diameter, spherical, iron oxide particles were synthesized as the mobile colloidal phase. The column packing material was retrieved from a sand and gravel aquifer on Cape Cod, MA. Previous studies have indicated enhanced stability and transpo
Authors
Robert W. Puls, Cynthia J. Paul, Donald A. Clark
Landscape linkages between geothermal activity and solute composition and ecological response in surface waters draining the Atlantic slope of Costa Rica
Surface waters draining three different volcanoes in Costa Rica, ranging from dormant to moderately active to explosive, have a wide range of solute compositions that partly reflects the contribution of different types of solute-rich, geothermal waters. Three major physical transport vectors affect flows of geothermally derived solutes: thermally driven convection of volcanic gases and geothermal
Authors
Catherine M. Pringle, Gary L. Rowe, Frank J. Triska, Jose F. Fernandez, John West
Simulation of fluid distributions observed at a crude oil spill site incorporating hysteresis, oil entrapment, and spatial variability of hydraulic properties
Subsurface oil, water, and air saturation distributions were determined using 146 samples collected from seven boreholes along a 120-m transect at a crude oil spill site near Bemidji, Minnesota. The field data, collected 10 years after the spill, show a clearly defined oil body that has an oil saturation distribution that appears to be influenced by sediment heterogeneities and water table fluctua
Authors
H.I. Essaid, W.N. Herkelrath, K.M. Hess
Fate and transport of bacteria injected into aquifers
Advances in our understanding of the fate and transport of bacteria introduced into aquifers, including the potential use of genetically engineered bacteria for biorestoration, are highlighted by new findings in the following areas: modeling of bacterial attachment during transport through porous media, the long-term survival of a chlorobenzoate-degrading bacterium injected into a contaminated san
Authors
Ronald W. Harvey