Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 3746
Spatial and temporal changes in microbial community structure associated with recharge-influenced chemical gradients in a contaminated aquifer
In a contaminated water‐table aquifer, we related microbial community structure on aquifer sediments to gradients in 24 geochemical and contaminant variables at five depths, under three recharge conditions. Community amplified ribsosomal DNA restriction analysis (ARDRA) using universal 16S rDNA primers and denaturing gradient gel electrophoresis (DGGE) using bacterial 16S rDNA primers indicated: (
Authors
S.K. Haack, L.R. Fogarty, T.G. West, E.W. Alm, J.T. McGuire, D.T. Long, D.W. Hyndman, L.J. Forney
Herbicide concentrations in the Mississippi River basin: The importance of chloroacetanilide herbicide degradates
The proportion of chloroacetanilide herbicide degradates, specifically the ethane sulfonic (ESA) and oxanilic (OA) acids, averaged 70% of the total herbicide concentration in samples from the Upper Mississippi River. In samples from the Missouri River and the Ohio River, the proportion of chloroacetanilide degradates in the total herbicide concentration was much less, 24% and 41%, respectively. Th
Authors
R.A. Rebich, R.H. Coupe, E. M. Thurman
Historical trends in occurrence and atmospheric inputs of halogenated volatile organic compounds in untreated ground water used as a source of drinking water
Analyses of samples of untreated ground water from 413 community-, non-community- (such as restaurants), and domestic-supply wells throughout the US were used to determine the frequency of detection of halogenated volatile organic compounds (VOCs) in drinking-water sources. The VOC data were compiled from archived chromatograms of samples analyzed originally for chlorofluorocarbons (CFCs) by purge
Authors
S.D. Shapiro, E. Busenberg, M. J. Focazio, Niel Plummer
Distribution of total and methyl mercury in sediments along Steamboat Creek (Nevada, USA)
In the late 1800s, mills in the Washoe Lake area, Nevada, used elemental mercury to remove gold and silver from the ores of the Comstock deposit. Since that time, mercury contaminated waste has been distributed from Washoe Lake, down Steamboat Creek, and to the Truckee River. The creek has high mercury concentrations in both water and sediments, and continues to be a constant source of mercury to
Authors
J. Stamenkovic, M.S. Gustin, M. C. Marvin-DiPasquale, B.A. Thomas, J.L. Agee
Testing density-dependent groundwater models: Two-dimensional steady state unstable convection in infinite, finite and inclined porous layers
This study proposes the use of several problems of unstable steady state convection with variable fluid density in a porous layer of infinite horizontal extent as two-dimensional (2-D) test cases for density-dependent groundwater flow and solute transport simulators. Unlike existing density-dependent model benchmarks, these problems have well-defined stability criteria that are determined analytic
Authors
D. Weatherill, C.T. Simmons, C.I. Voss, N.I. Robinson
Reach-scale cation exchange controls on major ion chemistry of an Antarctic glacial meltwater stream
McMurdo dry valleys of Antarctica represent the largest of the ice-free areas on the Antarctic continent, containing glaciers, meltwater streams, and closed basin lakes. Previous geochemical studies of dry valley streams and lakes have addressed chemical weathering reactions of hyporheic substrate and geochemical evolution of dry valley surface waters. We examine cation transport and exchange reac
Authors
Michael N. Gooseff, Diane M. McKnight, Robert L. Runkel
Enhanced gas-phase transport in a deep unsaturated zone, Amargosa Desert (U.S.A.)
No abstract available.
Authors
Michelle Ann Walvoord, David A. Stonestrom
Monitoring radionuclide contamination in the unsaturated zone - Lessons learned at the Amargosa Desert Research Site, Nye County, Nevada
Contaminant-transport processes are being investigated at the U.S. Geological Survey’s Amargosa Desert Research Site (A DRS), adjacent to the Nation’s first commercial disposal facility for low-level radioactive waste. Gases containing tritium and radiocarbon are migrating through a 110-m thick unsaturated zone from unlined trenches that received waste from 1962 to 1992. Results relevant to long-
Authors
David A. Stonestrom, Jared D. Abraham, Brian J. Andraski, Ronald J. Baker, C. Justin Mayers, Robert L. Michel, David E. Prudic, Robert G. Striegl, Michelle Ann Walvoord
Object-based inversion of crosswell radar tomography data to monitor vegetable oil injection experiments
Crosswell radar methods can be used to dynamically image ground-water flow and mass transport associated with tracer tests, hydraulic tests, and natural physical processes, for improved characterization of preferential flow paths and complex aquifer heterogeneity. Unfortunately, because the raypath coverage of the interwell region is limited by the borehole geometry, the tomographic inverse proble
Authors
John W. Lane, Frederick D. Day-Lewis, Roelof J. Versteeg, Clifton C. Casey
Alkaline hydrolysis/polymerization of 2,4,6-Trinitrotoluene: Characterization of products by 13C and 15N NMR
Alkaline hydrolysis has been investigated as a nonbiological procedure for the destruction of 2,4,6-trinitrotoluene (TNT) in explosives contaminated soils and munitions scrap. Nucleophilic substitutions of the nitro and methyl groups of TNT by hydroxide ion are the initial steps in the alkaline degradation of TNT. Potential applications of the technique include both in situ surface liming and ex s
Authors
Kevin A. Thorn, Philip G. Thorne, Larry G. Cox
Impact of clay minerals on sulfate-reducing activity in aquifers
Previous studies have shown that sulfate-reduction activity occurs in a heterogeneous manner throughout the terrestrial subsurface. Low-activity regions are often observed in the presence of clay minerals. Here we report that clays inhibit sulfate reduction activity in sediments and in a pure culture of Desulfovibriovulgaris. Clay minerals including bentonite and kaolinite inhibited sulfate reduct
Authors
D. Wong, J.M. Suflita, J.P. McKinley, L.R. Krumholz
Importance of clay size minerals for Fe(III) respiration in a petroleum-contaminated aquifer
The availability of Fe(III)-bearing minerals for dissimilatory Fe(III) reduction was evaluated in sediments from a petroleum-contaminated sandy aquifer near Bemidji, Minnesota (USA). First, the sediments from a contaminated area of the aquifer, in which Fe(III) reduction was the predominant terminal electron accepting process, were compared with sediments from a nearby, uncontaminated site. Data f
Authors
Evgenya S. Shelobolina, Robert T. Anderson, Yury N. Vodyanitskii, Anatolii V. Sivtsov, Richard Yuretich, Derek R. Lovely