Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 3787
Solubility of jarosite solid solutions precipitated from acid mine waters, Iron Mountain, California
Because of the common occurrence of 15 to 25 mole percent hydronium substitution on the alkali site in jarosites, it is necessary to consider the hydronium content of jarosites in any attempt at rigorous evaluation of jarosite solubility or of the saturation state of natural waters with respect to jarosite. A Gibbs free energy of 3293.5±2.1 kJ mol-1 is recommended for a jarosite solid solution of
Authors
Charles N. Alpers, D. Kirk Nordstrom, J. W. Ball
Spectroscopic evidence for organic diacid complexation with dissolved silica in aqueous systems—I. Oxalic acid
Increased solubility of quartz and mobilization in contaminated groundwater due to the complexation with dissolved organic acids has been recently proposed [Bennett and Siegel, Nature326, 684–686 (1987)]. Using laser Raman and Fourier transform infrared spectroscopies, we have examined mixed solutions of oxalic and silicic acids at near neutral pH in the tenth molar concentration ranges in an atte
Authors
N.A. Marley, P. Bennett, D.R. Janecky, J.S. Gaffney
Use of on-site high performance liquid chromatography to evaluate the magnitude and extent of organic contaminants in aquifers
Appraisal of ground water contaminated by organic substances raises problems of difficult sample collection and timely chemical analysis. High-performance liquid chromatography was evaluated for on-site determination of specific organic contaminants in ground water samples and was used at three study sites. Organic solutes were determined directly in water samples, with little or no preparation, a
Authors
D.F. Goerlitz, B.J. Franks
Retardation of ammonium and potassium transport through a contaminated sand and gravel aquifer: The Role of cation exchange
The role of cation exchange in the retardation of ammonium (NH4+) and potassium (K+) transport in a shallow sand and gravel aquifer was evaluated by use of observed distributions of NH4+ and K+ within a plume of sewage-contaminated groundwater, small-scale tracer injection tests, and batch sorption experiments on aquifer material. Both NH4+ and K+ were transported ???2 km in the 4-km-long contamin
Authors
M.L. Ceazan, E.M. Thurman, R. L. Smith
Book review--"Coupled processes associated with nuclear waste repositories"
No abstract available.
Authors
D. Kirk Nordstrom
The dissolution of quartz in dilute aqueous solutions of organic acids at 25°C
The dissolution of quartz in dilute aqueous solutions of organic acids at 25° and standard pressure was investigated by the batch dissolution method. The bulk dissolution rate of quartz in 20 mmole/Kg citrate solutions at pH 7 was 8 to 10 times faster than that in pure water. After 1750 hours the concentration of dissolved silica in the citrate solution was 167 μmole/Kg compared to 50 μmole/Kg in
Authors
P.C. Bennett, M.E. Melcer, D. I. Siegel, J.P. Hassett
Arsenic in ground water of the Western United States
Natural occurrences of ground water with moderate (10 to 50 micrograms per liter) to high (greater than 50 micrograms per liter) concentrations of arsenic are common throughout much of the Western United States. High concentrations of arsenic are generally associated with one of four geochemical environments: (1) basin-fill deposits of alluvial-lacustrine origin, particularly in semiarid areas, (2
Authors
Alan H. Welch, Michael S. Lico, Jennifer L. Hughes
Denitrification in a sand and gravel aquifer
Denitrification was assayed by the acetylene blockage technique in slurried core material obtained from a freshwater sand and gravel aquifer. The aquifer, which has been contaminated with treated sewage for more than 50 years, had a contaminant plume greater than 3.5-km long. Near the contaminant source, groundwater nitrate concentrations were greater than 1 mM, whereas 0.25 km downgradient the ce
Authors
R. L. Smith, J.H. Duff
Iron photoreduction and oxidation in an acidic mountain stream
In a small mountain stream in Colorado that receives acidic mine drainage, photoreduction of ferric iron results in a well-defined increase in dissolved ferrous iron during the day. To quantify this process, an instream injection of a conservative tracer was used to measure discharge at the time that each sample was collected. Daytime production of ferrous iron by photoreduction was almost four ti
Authors
D.M. McKnight, B. A. Kimball, K.E. Bencala
Internal inconsistencies in dispersion-dominated models that incorporate chemical and microbial kinetics
Current understanding of transport processes in aquifers is limited by lack of precise point chemical concentration measurements. Recently, however, some careful measurements of vertical chemical concentration profiles have been made at several locations around the world that appear to support a consistent picture concerning the persistence of large vertical concentration gradients in aquifers and
Authors
Fred J. Molz, Mark A. Widdowson
Discussion of "Flume tests on hydrocarbon reaeration tracer gases"
No abstract available.
Authors
Ronald E. Rathbun
Use of electrothermal vaporization-multiple-wavelength absorption spectrometry to qualitatively screen for the presence of polycyclic aromatic hydrocarbons
No abstract available
Authors
Joseph M. Shekiro, Rodney K. Skogerboe, Howard E. Taylor