Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 3787
Practical considerations for measuring hydrogen concentrations in groundwater
Several practical considerations for measuring concentrations of dissolved molecular hydrogen (H2) in groundwater including 1 sampling methods 2 pumping methods and (3) effects of well casing materials were evaluated. Three different sampling methodologies (a downhole sampler, a gas- stripping method, and a diffusion sampler) were compared. The downhole sampler and gas-stripping methods gave simil
Authors
F. H. Chapelle, D. A. Vroblesky, J.C. Woodward, D. R. Lovley
Logistic model of nitrate in streams of the upper-midwestern United States
Nitrate in surface water can have adverse effects on aquatic life and, in drinking-water supplies, can be a risk to human health. As part of a regional study, nitrates as N (NO3-N) was analyzed in water samples collected from streams throughout 10 Midwestern states during synoptic surveys in 1989, 1990, and 1994. Data from the period immediately following crop planting at 124 sites were analyzed d
Authors
D. K. Mueller, B. C. Ruddy, W.A. Battaglin
A theoretically based determination of bowen-ratio fetch requirements
Determination of fetch requirements for accurate Bowen-ratio measurements of latent- and sensible-heat fluxes is more involved than for eddy-correlation measurements because Bowen-ratio sensors are located at two heights, rather than just one. A simple solution to the diffusion equation is used to derive an expression for Bowen-ratio fetch requirements, downwind of a step change in surface fluxes.
Authors
D.I. Stannard
Near field receiving water monitoring of trace metals in Clams (Macoma balthica) and sediments near the Palo Alto and San Jose/Sunnyvale Water Quality Control Plants in South San Francisco Bay: 1996
No abstract available.
Authors
S. N. Luoma, D.J. Cain, C. Brown, M. Hornberger, R. Bouse
In situ ecosystem effects of trace contaminants in San Francisco Bay Estuary - The necessary link to establishing water quality standards II
No abstract available.
Authors
Francis Parcheso, C. L. Brown, J.K. Thompson, S.L. Luoma
Soil, plant, and structural considerations for surface barriers in arid environments: Application of results from studies in the Mojave Desert near Beatty, Nevada
The suitability of a waste-burial site depends on hydrologic processes that can affect the near-surface water balance. In addition, the loss of burial trench integrity by erosion and subsidence of trench covers may increase the likelihood of infiltration and percolation, thereby reducing the effectiveness of the site in isolating waste. Although the main components of the water balance may be defi
Authors
Brian J. Andraski, David E. Prudic
Analysis of the Cape Cod tracer data
An analysis of the Cape Cod test was performed using several first- and higher-order theoretical models. We compare conditional and unconditional solutions of the transport equation and employ them for analysis of the experimental data. We consider spatial moments, mass breakthrough curves, and the distribution of the solute mass in space. The concentration measurements were also analyzed using th
Authors
Souheil Ezzedine, Yoram Rubin
Tritium/3He dating of river infiltration: An example from the Danube in the Szigetköz area, Hungary
3H, He, 4He, and Ne data were obtained from a shallow ground-water system being recharged by bank infiltration from the Danube River in northwestern Hungary. After correting for excess air, 4He and Ne concentrations reflect a recharge temperature of about 9° C., close to the mean annual temperature of the Danube (10.4° C). Values of H plus 3Hetrit (“initial tritium”) as a function of the tritium/H
Authors
M. Stute, J. Deák, K. Révész, J. K. Böhlke, E. Deseö, R. Weppernig, P. Schlosser
Potential for intrinsic bioremediation of a DNT-contaminated aquifer
Microorganisms indigenous to a shallow aquifer, which underlies an explosives-contaminated site, mineralized 28% of [U-ring-14C] 2,4–dinitrotoluene to 14CO2 within 28 days under aerobic conditions. Approximately 20% of added 2,4–dinitrotoluene remained undegraded at the end of the incubation while approximately 22% and 6% were transformed to 4–amino-2–nitrotoluene and 2–amino-4–nitrotoluene, respe
Authors
P. M. Bradley, F. H. Chapelle, J. E. Landmeyer, J.G. Schumacher
Deep well injection of brine from Paradox Valley, Colorado: Potential major precipitation problems remediated by nanofiltration
Groundwater brine seepage into the Dolores River in Paradox Valley, Colorado, increases the dissolved solids load of the Colorado River annually by ∼2.0 × 108 kg. To abate this natural contamination, the Bureau of Reclamation plans to pump ∼3540 m3/d of brine from 12 shallow wells located along the Dolores River. The brine, with a salinity of 250,000 mg/L, will be piped to the deepest (4.9 km) dis
Authors
Yousif K. Kharaka, Gil Ambats, James J. Thordsen, Roy A. Davis
Quantifying macropore recharge: Examples from a semi-arid area
The purpose of this paper is to illustrate the significantly increased resolution of determining macropore recharge by combining physical, chemical, and isotopic methods of analysis. Techniques for quantifying macropore recharge were developed for both small-scale (1 to 10 km2) and regional-scale areas in and semi-arid areas. The Southern High Plains region of Texas and New Mexico was used as a re
Authors
W.W. Wood, Ken A. Rainwater, D.B. Thompson
Binding of pyrene to aquatic and commercial humic substances: The role of molecular weight and aromaticity
The binding of pyrene to a number of humic substances isolated from various aquatic sources and a commercial humic acid was measured using the solubility enhancement method. The humic materials used in this study were characterized by various spectroscopic and liquid chromatography methods. A strong correlation was observed between the pyrene binding coefficient, K(doc), and the molecular weights,
Authors
Y.-P. Chin, G. R. Aiken, K.M. Danielsen