Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 3787
A model for trace metal sorption processes at the calcite surface: Adsorption of Cd2+ and subsequent solid solution formation
The rate of Cd2+ sorption by calcite was determined as a function of pH and Mg2+ in aqueous solutions saturated with respect to calcite but undersaturated with respect to CdCO3. The sorption is characterized by two reaction steps, with the first reaching completion within 24 hours. The second step proceeded at a slow and nearly constant rate for at least 7 days. The rate of calcite recrystallizati
Authors
J.A. Davis, C. C. Fuller, A.D. Cook
Fate and movement of azaarenes and their anaerobic biotransformation products in an aquifer contaminated by wood-treatment chemicals
Infiltration of wastes containing creosote and pentachlorophenol from surface impoundments at an abandoned wood-treatment facility near Pensacola, Florida, resulted in contamination of the underlying sand and gravel aquifer. Pond sludges and sediments near the source were contaminated with 2- to 5-ring azaarenes having log Kow values of from 2.0 to 5.6. However, the ground water contained only aza
Authors
W. E. Pereira, C.E. Rostad, D.M. Updegraff, J.L. Bennett
Determination of alkylbenzenesulfonate surfactants in groundwater using macroreticular resins and carbon-13 nuclear magnetic resonance spectrometry
Alkylbenzenesulfonate surfactants were determined in groundwater at concentrations as low as 0.3 mg/L. The method uses XAD-8 resin for concentration, followed by elution with methanol, separation of anionic and nonionic surfactants by anion exchange, quantitation by titration, and identification by 13C nuclear magnetic resonance spectrometry. Laboratory standards and field samples containing strai
Authors
E. Michael Thurman, T. Willoughby, Larry B. Barber, Kevin A. Thorn
Growth determinations for unattached bacteria in a contaminated aquifer
Growth rates of unattached bacteria in groundwater contaminated with treated sewage and collected at various distances from the source of contamination were estimated by using frequency of dividing cells and tritiated-thymidine uptake and compared with growth rates obtained with unsupplemented, closed-bottle incubations. Estimates of bacterial generation times [(In 2)/μ] along a 3-km-long transect
Authors
R.W. Harvey, L.H. George
Big Soda Lake (Nevada). 1. Pelagic bacterial heterotrophy and biomass
Bacterial activities and abundance were measured seasonally in the water column of meromictic Big Soda Lake which is divided into three chemically distinct zones: aerobic mixolimnion, anaerobic mixolimnion, and anaerobic monimolimnion. Bacterial abundance ranged between 5 and 52 x 106 cells ml−1, with highest biomass at the interfaces between these zones: 2–4 mg C liter−1 in the photosynthetic bac
Authors
Jon P. Zehr, Ronald W. Harvey, Ronald S. Oremland, James E. Cloern, Leah H. George, Judith L. Lane
Volatilization of ethylene dibromide from water
Overall mass-transfer coefficients for the volatilization of ethylene dibromide from water were measured simultaneously with the oxygen absorption coefficient in a laboratory stirred tank. Coefficients were measured as a function of mixing conditions in the water for two windspeeds. The ethylene dibromide mass-transfer coefficient depended on windspeed; the ethylene dibromide liquid-film coefficie
Authors
R. E. Rathbun, D. Y. Tai
A compositional multiphase model for groundwater contamination by petroleum products: 2. Numerical solution
In this paper we develop a numerical solution to equations developed in part 1 (M. Y. Corapcioglu and A. L. Baehr, this issue) to predict the fate of an immiscible organic contaminant such as gasoline in the unsaturated zone subsequent to plume establishment. This solution, obtained by using a finite difference scheme and a method of forward projection to evaluate nonlinear coefficients, provides
Authors
Arthur L. Baehr, M. Yavuz Corapcioglu
Solute transport with equilibrium aqueous complexation and either sorption or ion exchange: Simulation methodology and applications
Methodologies that account for specific types of chemical reactions in the simulation of solute transport can be developed so they are compatible with solution algorithms employed in existing transport codes. This enables the simulation of reactive transport in complex multidimensional flow regimes, and provides a means for existing codes to account for some of the fundamental chemical processes t
Authors
F.M. Lewis, Clifford I. Voss, J. Rubin
Thermodynamics of aragonite-strontianite solid solutions: Results from stoichiometric solubility at 25 and 76°C
Dissolution of synthetic strontianite-aragonite solid solutions was followed analytically to stoichiometric saturation using large solid to solution ratios in CO2-H2O solution at 25 and 76°C. The compositional dependence of the equilibrium constant was calculated from the composition of saturated (stoichiometric) solutions and used to calculate the activities and activity coefficients of CaCO3 and
Authors
Niel Plummer, E. Busenberg
Stable isotope dilution analysis of hydrologic samples by inductively coupled plasma mass spectrometry
Inductively coupled plasma mass spectrometry is employed in the determination of Ni, Cu, Sr, Cd, Ba, Ti, and Pb in nonsaline, natural water samples by stable isotope dilution analysis. Hydrologic samples were directly analyzed without any unusual pretreatment. Interference effects related to overlapping isobars, formation of metal oxide and multiply charged ions, and matrix composition were identi
Authors
John R. Garbarino, Howard E. Taylor
Characterization of fracture permeability with high-resolution vertical flow measurements during borehole pumping.
The distribution of fracture permeability in granitic rocks was investigated by measuring the distribution of vertical flow in boreholes during periods of steady pumping. Pumping tests were conducted at two sites chosen to provide examples of moderately fractured rocks near Mirror Lake, New Hampshire and intensely fractured rocks near Oracle, Arizona. A sensitive heat-pulse flowmeter was used for
Authors
Frederick L. Paillet, A.E. Hess, C.H. Cheng, E. Hardin
Playa-lake basins on the Southern High Plains of Texas and New Mexico: Part I. Hydrologic, geomorphic, and geologic evidence for their development
Playa-lake basins of the Southern High Plains, Texas and New Mexico, may originate wherever water periodically can collect in a surficial depression. They expand, however, by hydrologic and geomorphic processes including (1) dissolution of lithologic carbonates by infiltrating water; (2) transport downward of fine-grained clastic and organic material by the infiltrating ground water, leading to co
Authors
Waite Osterkamp, W.W. Wood