Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
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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
Methane production and consumption monitored by stable H and C isotope ratios at a crude oil spill site, Bemidji, Minnesota
Stable isotopic ratios of C and H in dissolved CH4 and C in dissolved inorganic C in the ground water of a crude-oil spill near Bemidji, Minnesota, support the concept of CH4production by acetate fermentation with a contemporaneous increase in HCO3−concentration. Methane concentrations in the saturated zone decrease from 20.6 mg L−1 to less than 0.001 mg L−1 along the investigated flow path. Disso
Authors
Kinga Revesz, Tyler B. Coplen, Mary J. Baedecker, Pierre D. Glynn
Combined use of groundwater dating, chemical, and isotopic analyses to resolve the history and fate of nitrate contamination in two agricultural watersheds, Atlantic coastal plain, Maryland
The history and fate of groundwater nitrate (NO3−) contamination were compared in 2 small adjacent agricultural watersheds in the Atlantic coastal plain by combined use of chronologic (CCl2F2, 3H), chemical (dissolved solids, gases), and isotopic (δ15N,δ13C, δ34S) analyses of recharging groundwaters, discharging groundwaters, and surface waters. The results demonstrate the interactive effects of c
Authors
J.K. Böhlke, J. M. Denver
Estimating 14C groundwater ages in a methanogenic aquifer
This paper addresses the problem of 14C age dating of groundwaters in a confined regional aquifer affected by methanogenesis. Increasing CH4 concentrations along the groundwater flow system and 13C and 14C isotopic data for dissolved inorganic carbon, dissolved organic carbon, and CH4 clearly show the effect of methanogenesis on groundwater chemistry. Inverse reaction path modeling using NETPATH i
Authors
Ramon Aravena, Leonard I Wassenaar, Niel Plummer
Pesticide, nutrient, water-discharge and physical-property data for the Mississippi River and some of its tributaries, April 1991-September 1992
No abstract available.
Authors
Richard H. Coupe
Intercomparison experiments on dissolved trace-metal data from the Mississippi River and some of its tributaries, 1989-90
No abstract available.
Authors
Howard E. Taylor, A.M. Shiller, J.R. Garbarino, T.I. Brinton
Concentration and transport data for selected dissolved inorganic constituents and dissolved organic carbon in water collected from the Mississippi River and some of its tributaries, July 1991-May 1992
No abstract available.
Authors
John R. Garbarino, Ronald C. Antweiler, T.I. Brinton, D.A. Roth, Howard E. Taylor
Spatial data in geographic information system format on agricultural chemical use, land use, and cropping practices in the United States
The spatial data in geographic information system format described in this report consist of estimates for all counties in the conterminous United States of the annual use of 96 herbicides in 1989; annual sales of nitrogen fertilizer, in tons, for 1985-91; and agricultural expenses, land use, chemical use, livestock holdings, and cropping practices in 1987. The source information, originally in ta
Authors
William A. Battaglin, Donald A. Goolsby
Supporting data for hydrologic studies in San Francisco Bay, California: Meteorological measurements at the Port of Redwood City during 1992-1994
Meteorological data were collected during 1992-94 at the Port of Redwood City, California, to support hydrologic studies in southern San Francisco Bay. The meteorological variables that were measured were air temperature, atmospheric pressure, quantum flux (insolation), and four parameters of wind speed and direction: scalar mean horizontal wind speed, (vector) resultant horizontal wind speed, res
Authors
Laurence E. Schemel
Measurements of salinity, temperature, and tides in south San Francisco Bay, California, at Dumbarton Bridge: 1990-93 water years
The U.S. Geological Survey measures salinity, temperature, and water levels (tides) in southern San Francisco Bay at Dumbarton Bridge as part of a cooperative program with the California State Department of Water Resources. During water years 1990-93, measurements were made at 15-minute intervals with electonic sensors located approximately one meter above the substrate in approximately six meters
Authors
Laurence E. Schemel
Dissolved pesticide data for the San Joaquin River at Vernalis and the Sacramento River at Sacramento, California, 1991-94
Water samples were collected from sites on the San Joaquin and Sacramento Rivers, California and were analyzed for dissolved organic pesticides. This data collection and analysis are a part of an ongoing project by the U.S. Geological Survey Toxic Contaminants Hydrology program to determine the fate and transport of organic pesticides that enter the San Francisco Bay Estuary. Concentrations of sel
Authors
Dorene E. MacCoy, Kathryn L. Crepeau, Kathryn Kuivila
The Mirror Lake fractured-rock research site: A multidisciplinary research effort in characterizing ground-water flow and chemical transport in fractured rock
No abstract available.
Authors
Allen M. Shapiro, P. A. Hsieh, Thomas C. Winter