Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 4094
Use of a reactive gas transport model to determine rates of hydrocarbon biodegradation in unsaturated porous media
A mathematical model is presented that simulates the transport and reaction of any number of gaseous phase constituents (e.g. CO2, O2, N2, and hydrocarbons) in unsaturated porous media. The model was developed as part of a method to determine rates of hydrocarbon biodegradation associated with natural cleansing at petroleum product spill sites. The one-dimensional model can be applied to analyze d
Authors
Arthur L. Baehr, Ronald J. Baker
Evaluation of lipid-containing semipermeable membrane devices for monitoring organochlorine contaminants in the Upper Mississippi river
Organochlorine contaminants sequestered in lipid-containing semipermeable membrane devices (SPMDs) were compared to those found in tangential-flow ultrafilter permeates as part of a pilot study at 10 sites in the Upper Mississippi River system. Caged and feral fish from three primary sites were also analyzed for comparison. Concentrated organochlorine (OC) compounds were readily extracted from the
Authors
Geoffrey S. Ellis, Colleen E. Rostad, James N. Huckins, Christopher J. Schmitt, Patrick MacCarthy
Hydrogeology and geochemistry of acid mine drainage in ground water in the vicinity of Penn Mine and Camanche Reservoir, Calaveras County, California: First-year summary
Acid drainage from the Penn Mine in Calaveras County, California, has caused contamination of ground water between Mine Run Dam and Camanche Reservoir. The Penn Mine was first developed in the 1860's primarily for copper and later produced lesser amounts of zinc, lead, silver, and gold from steeply dipping massive sulfide lenses in metamorphic rocks. Surface disposal of sulfidic waste rock and tai
Authors
S. N. Hamlin, Charles N. Alpers
Hydrologic data from the lower Cedar River Basin, Iowa, 1989-91
Hydrologic data were collected from May 1989 through July 1991 from the Cedar River and the adjacent alluvial aquifer. The data were collected during various flow regimes of the river to evaluate the movement of agricultural chemicals between surface water and ground water. Water-quality samples from 34 surface-water sites and 95 ground-water sites were analyzed for 11 herbicides, 2 dealkylated at
Authors
P.M. Schulmeyer, K.K. Barnes, P. J. Squillace
Benthic macrofauna data for San Francisco Bay, California, September 1986
Benthic macrofauna were collected during September 1986 to evaluate locations for long-term monitoring stations as part of the U.S. Geological Survey Regional Effects Monitoring Program in San Francisco Bay, California. Three to ten replicate samples were collected with a modified Van Veen sampler (0.05 m2 area) at ten locations. One box core sample (0.06 m2 area) was collected at seven to the ten
Authors
Laurence E. Schemel, J.K. Thompson, J.G. Harmon, B. T. Yost
A computer program (MACPUMP) for interactive aquifer-test analysis
This report introduces MACPUMP (Version 1.0), an aquifer-test-analysis package for use with Macintosh4 computers. The report outlines the input- data format, describes the solutions encoded in the program, explains the menu-items, and offers a tutorial illustrating the use of the program. The package reads list-directed aquifer-test data from a file, plots the data to the screen, generates and plo
Authors
F. D. Day-Lewis, M.A. Person, Leonard F. Konikow
Data on natural organic substances in dissolved, colloidal, suspended-silt and -clay, and bed-sediment phases in the Mississippi River and some of its tributaries, 1991-92
No abstract available.
Authors
J. A. Leenheer, L. B. Barber, C.E. Rostad, T.I. Noyes
A Lagrangian stochastic model for aerial spray transport above an oak forest
An aerial spray droplets' transport model has been developed by applying recent advances in Lagrangian stochastic simulation of heavy particles. A two-dimensional Lagrangian stochastic model was adopted to simulate the spray droplet dispersion in atmospheric turbulence by adjusting the Lagrangian integral time scale along the drop trajectory. The other major physical processes affecting the transp
Authors
Yansen Wang, David R. Miller, Dean E. Anderson, Michael L. McManus
Hydrologic and geochemical effects on oxygen uptake in bottom sediments of an effluent-dominated river
More than 95% of the water in the South Platte River downstream from the largest wastewater treatment plant serving the metropolitan Denver, Colorado, area consists of treated effluent during some periods of low flow. Fluctuations in effluent-discharge rates caused daily changes in river stage that promoted exchange of water between the river and bottom sediments. Groundwater discharge measurement
Authors
P. B. McMahon, J.A. Tindall, J.A. Collins, K.J. Lull, J.R. Nuttle
Gross-beta activity in ground water: natural sources and artifacts of sampling and laboratory analysis
Gross-beta activity has been used as an indicator of beta-emitting isotopes in water since at least the early 1950s. Originally designed for detection of radioactive releases from nuclear facilities and weapons tests, analysis of gross-beta activity is widely used in studies of naturally occurring radioactivity in ground water. Analyses of about 800 samples from 5 ground-water regions of the Unite
Authors
Alan H. Welch, Zoltan Szabo, David L. Parkhurst, Peter C. Van Metre, Ann H. Mullin
Geometry of sorbed arsenate on ferrihydrite and crystalline FeOOH: Re-evaluation of EXAFS results and topological factors in predicting sorbate geometry, and evidence for monodentate complexes
Manceau's (1995) reinterpretation of some of our EXAFS results (Waychunas et al., 1993) has been analyzed using both old and newly collected data in an attempt to clarify the nature of proposed monodentate and edge-sharing bidentate arsenate complexes on the ferrihydrite surface. It is shown that EXAFS analysis utilizing data with sufficient k-range does indicate the presence of relatively short A
Authors
Glenn A. Waychunas, James A. Davis, Christopher C. Fuller
State-dependent anisotrophy: Comparison of quasi-analytical solutions with stochastic results for steady gravity drainage
Anisotropy in large-scale unsaturated hydraulic conductivity of layered soils changes with the moisture state. Here, state-dependent anisotropy is computed under conditions of large-scale gravity drainage. Soils represented by Gardner's exponential function are perfectly stratified, periodic, and inclined. Analytical integration of Darcy’s law across each layer results in a system of nonlinear equ
Authors
Timothy R. Green, David L. Freyberg