Molecular analysis of microbial community structures in pristine and contaminated aquifers: Field and laboratory microcosm experiments
Y. Shi, M.D. Zwolinski, M.E. Schreiber, J.M. Bahr, G.W. Sewell, W.J. Hickey
1999, Applied and Environmental Microbiology (65) 2143-2150
This study used phylogenetic probes in hybridization analysis to (i) determine in situ microbial community structures in regions of a shallow sand aquifer that were oxygen depleted and fuel contaminated (FC) or aerobic and noncontaminated (NC) and (ii) examine alterations in microbial community structures resulting from exposure to toluene and/or...
Isotopic composition of water in a deep unsaturated zone beside a radioactive-waste disposal area near Beatty, Nevada
David A. Stonestrom, David E. Prudic, Robert G. Striegl
David W. Morganwalp, Herbert T. Buxton, editor(s)
1999, Report, U.S. Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Charleston, South Carolina, March 8-12, 1999: Volume 3 (Part C) (WRI 99-4018C)
The isotopic composition of water in deep unsaturated zones is of interest because it provides information relevant to hydrologic processes and contaminant migration. Profiles of oxygen-18 (18O), deuterium (D), and tritium (3H) from a 110-meter deep unsaturated zone, together with data on the isotopic composition of ground water...
Overview of research on water, gas, and radionuclide transport at the Amargosa Desert Research Site, Nevada: A section in U.S. Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Charleston, South Carolina, March 8-12, 1999: Volume 3 (Part C) (WRI 99-4018C)
Brian J. Andraski, David A. Stonestrom
David W. Morganwalp, Herbert T. Buxton, editor(s)
1999, Report, U.S. Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Charleston, South Carolina, March 8-12, 1999: Volume 3 (Part C) (WRI 99-4018C)
Studies at the U.S. Geological Survey Amargosa Desert Research Site have focused on characterizing factors and processes that control transport and fate of contaminants in arid environments. This paper summarizes research results that have been published through 1998. Results have improved understanding of water and gas movement through a thick...
Tritium in water vapor in the shallow unsaturated zone at the Amargosa Desert Research Site
Richard W. Healy, Robert G. Striegl, Robert L. Michel, David E. Prudic, Brian J. Andraski
David W. Morganwalp, Herbert T. Buxton, editor(s)
1999, Report, U.S. Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Charleston, South Carolina, March 8-12, 1999: Volume 3 (Part C) (WRI 99-4018C)
Samples of water vapor in soil gas were obtained at the U.S. Geological Survey's Amargosa Desert Research Site in 1997 and 1998 from a depth of 1.5 m (meters) within a 300 m by 300 m grid that lies immediately to the south and west of a low-level radioactive-waste disposal...
Tritium and 14C concentrations in unsaturated-zone gases at test hole UZB-2, Amargosa Desert Research Site, 1994-98: A section in U.S. Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Charleston, South Carolina, March 8-12, 1999: Volume 3 (Part C) (WRI 99-4018C)>
David E. Prudic, Robert G. Striegl, Richard W. Healy, Robert L. Michel, Herbert Haas
David W. Morganwalp, Herbert T. Buxton, editor(s)
1999, Report, U.S. Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Charleston, South Carolina, March 8-12, 1999: Volume 3 (Part C) (WRI 99-4018C)
Tritium concentrations have been determined yearly since April 1994 from water-vapor samples collected at test hole UZB-2. The hole was drilled about 100 m (meters) south of the southwest corner of a commercial burial site for low-level radioactive wastes in September 1993. UZB-2 is equipped with ten 2.5-cm (centimeters) diameter...
The spring runoff pulse from the Sierra Nevada
D.R. Cayan, D. H. Peterson, L. Riddle, M. D. Dettinger, R. Smith
1999, Conference Paper, Proceedings of 14th Conference on Hydrology
Just about every year there is one major first pulse of snowmelt runoff (streamflow) that marks the transition from winter to spring in high elevation, snowmelt driven watersheds in the western United States. As a index, we have used the record of relatively pristine streamflow at the Merced River, Happy...
Wetlands of the Prairie Pothole Region: Invertebrate species composition, ecology, and management
N.H. Euliss Jr., D.A. Wrubleski, D.M. Mushet
D.P. Batzer, R.B. Rader, S.A. Wissinger, editor(s)
1999, Book chapter, Invertebrates in freshwater wetlands of North America: Ecology and management
The Prairie Pothole Region (PPR) of the United States and Canada is a unique area where shallow depressions created by the scouring action of Pleistocene glaciation interact with mid-continental climate variations to create and maintain a variety of wetland classes. These wetlands possess unique environmental and biotic characteristics that add...
Soil respiration at the Amargosa Desert Research site: A section in U.S. Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Charleston, South Carolina, March 8-12, 1999: Volume 3 (Part C) (WRI 99-4018C)
Alan C. Riggs, Robert G. Striegl, Florentino B. Maestas
David W. Morganwalp, Herbert T. Buxton, editor(s)
1999, Report, U.S. Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Charleston, South Carolina, March 8-12, 1999: Volume 3 (Part C) (WRI 99-4018C)
Automated opaque flux-chamber measurements of soil carbon dioxide (CO2) flux (soil respiration) into the atmosphere at the Amargosa Desert Research Site show seasonal and diel cycles of soil respiration that are closely linked with soil temperature and soil moisture. During 1998, soil respiration increased with soil warming through spring, reaching...
Inhibition of precipitation and aggregation of metacinnabar (mercuric sulfide) by dissolved organic matter isolated from the Florida Everglades
M. Ravichandran, G. R. Aiken, J. N. Ryan, M.M. Reddy
1999, Environmental Science & Technology (33) 1418-1423
Precipitation and aggregation of metacinnabar (black HgS) was inhibited in the presence of low concentrations (≥3 mg C/L) of humic fractions of dissolved organic matter (DOM) isolated from the Florida Everglades. At low Hg concentrations (≤5 × 10-8 M), DOM prevented the precipitation of metacinnabar. At moderate Hg...
The distribution of, and relation among, mercury and methylmercury, organic carbon, carbonate, nitrogen and phosphorus, in periphyton of the south Florida ecosystem
N.S. Simon, R. Spencer, T. Cox
1999, Toxicological and Environmental Chemistry (69) 417-433
Periphyton samples from Water Conservation Areas, Big Cypress National Preserve, and Everglades National Park in south Florida were analyzed for concentrations of total mercury, methylmercury, nitrogen, phosphorus, organic carbon, and inorganic carbon. Concentrations of total mercury in periphyton decrease slightly along a gradient from north‐to‐south. Both...
Tributary stream infiltration as a source of herbicides in an alluvial aquifer
Michael R. Burkart, William W. Simpkins, Paul J. Squillace, Martin Helmke
1999, Journal of Environmental Quality (28) 69-74
Where Walnut Creek flows across the South Skunk River alluvial aquifer, it provides a potential source of herbicides and herbicide metabolites. This straightened reach of the creek loses water and dissolved contaminants to the alluvial aquifer through a layer of fine-grained flood plain deposits. Estimates of...
Distribution of microbial physiologic types in an aquifer contaminated by crude oil
B.A. Bekins, E.M. Godsy, E. Warren
1999, Microbial Ecology (37) 263-275
We conducted a plume-scale study of the microbial ecology in the anaerobic portion of an aquifer contaminated by crude-oil compounds. The data provide insight into the patterns of ecological succession, microbial nutrient demands, and the relative importance of free-living versus attached microbial populations. The most probable number (MPN) method was...
Bioremediation of petroleum hydrocarbon-contaminated ground water: The perspectives of history and hydrology
F. H. Chapelle
1999, Ground Water (37) 122-132
Bioremediation, the use of microbial degradation processes to detoxify environmental contamination, was first applied to petroleum hydrocarbon-contaminated ground water systems in the early 1970s. Since that time, these technologies have evolved in some ways that were clearly anticipated early investigators, and in other ways that were not foreseen. The expectation...
Evaluation of stream water quality in Atlanta, Georgia, and the surrounding region (USA)
N.E. Peters, S.J. Kandell
1999, IAHS-AISH Publication 279-290
A water-quality index (WQI) was developed from historical data (1986-1995) for streams in the Atlanta Region and augmented with 'new' and generally more comprehensive biweekly data on four small urban streams, representing an industrial area, a developed medium-density residential area and developing and developed low-density residential areas. Parameter WQIs were...
Comparison of the stable-isotopic composition of soil water collected from suction lysimeters, wick samplers, and cores in a sandy unsaturated zone
M.K. Landon, G. N. Delin, S.C. Komor, C.P. Regan
1999, Journal of Hydrology (224) 45-54
Soil water collected from suction lysimeters and wick samplers buried in the unsaturated zone of a sand and gravel aquifer and extracted from soil cores were analyzed for stable oxygen and hydrogen isotope values. Soil water isotopic values differed among the three sampling methods in most cases. However, because each...
Processes governing phytoplankton blooms in estuaries. I: The local production-loss balance
L.V. Lucas, Jeffrey R. Koseff, J. E. Cloern, Stephen G. Monismith, J.K. Thompson
1999, Marine Ecology Progress Series (187) 1-15
The formation and spatial distribution of phytoplankton blooms in estuaries are controlled by (1) local mechanisms, which determine the production-loss balance for a water column at a particular spatial location (i.e. control if a bloom is possible), and (2) transport-related mechanisms, which govern biomass distribution (i.e. control if and where...
Modeling impact of storage zones on stream dissolved oxygen
S.C. Chapra, R.L. Runkel
1999, Journal of Environmental Engineering (125) 415-419
The Streeter-Phelps dissolved oxygen model is modified to incorporate storage zones. A dimensionless number reflecting enhanced decomposition caused by the increased residence time of the biochemical oxygen demand in the storage zone parameterizes the impact. This result provides a partial explanation for the high decomposition rates observed in shallow streams....
Indexing the relative abundance of age-0 white sturgeons in an impoundment of the lower Columbia River from highly skewed trawling data
T.D. Counihan, Allen I. Miller, M.J. Parsley
1999, North American Journal of Fisheries Management (19) 520-529
The development of recruitment monitoring programs for age-0 white sturgeons Acipenser transmontanus is complicated by the statistical properties of catch-per-unit-effort (CPUE) data. We found that age-0 CPUE distributions from bottom trawl surveys violated assumptions of statistical procedures based on normal probability theory. Further, no single data transformation uniformly satisfied these...
Hydraulic and geochemical performance of a permeable reactive barrier containing zero-valent iron, Denver Federal Center
P.B. McMahon, K.F. Dennehy, Mark W. Sandstrom
1999, Ground Water (37) 396-404
The hydraulic and geochemical performance of a 366 m long permeable reactive barrier (PRB) at the Denver Federal Center, Denver, Colorado, was evaluated. The funnel and gate system, which was installed in 1996 to intercept and remediate ground water contaminated with chlorinated aliphatic hydrocarbons (CAHs), contained four 12.2 m wide...
Dissolved sulfide distributions in the water column and sediment pore waters of the Santa Barbara Basin
J.S. Kuwabara, A. VanGeen, D.C. McCorkle, J.M. Bernhard
1999, Geochimica et Cosmochimica Acta (63) 2199-2209
Dissolved sulfide concentrations in the water column and in sediment pore waters were measured by square-wave voltammetry (nanomolar detection limit) during three cruises to the Santa Barbara Basin in February 1995, November–December 1995, and April 1997. In the water column, sulfide concentrations measured outside...
High-pressure size exclusion chromatography analysis of dissolved organic matter isolated by tangential-flow ultra filtration
C.R. Everett, Y.-P. Chin, G. R. Aiken
1999, Limnology and Oceanography (44) 1316-1322
A 1,000-Dalton tangential-flow ultrafiltration (TFUF) membrane was used to isolate dissolved organic matter (DOM) from several freshwater environments. The TFUF unit used in this study was able to completely retain a polystyrene sulfonate 1,800-Dalton standard. Unaltered and TFUF-fractionated DOM molecular weights were assayed by high-pressure size exclusion chromatography (HPSEC). The...
Prediction of episodic acidification in North-eastern USA: An empirical/mechanistic approach
T.D. Davies, M. Tranter, P.J. Wigington Jr., K.N. Eshleman, N.E. Peters, J. Van Sickle, David R. DeWalle, Peter S. Murdoch
1999, Hydrological Processes (13) 1181-1195
Observations from the US Environmental Protection Agency's Episodic Response Project (ERP) in the North-eastern United States are used to develop an empirical/mechanistic scheme for prediction of the minimum values of acid neutralizing capacity (ANC) during episodes. An acidification episode is defined as a hydrological event during which ANC decreases. The...
Are shifts in herbicide use reflected in concentration changes in Midwestern rivers?
W.A. Battaglin, D. A. Goolsby
1999, Environmental Science & Technology (33) 2917-2925
In many Midwestern rivers, elevated concentrations of herbicides occur during runoff events for 1-3 months following application. The highest or 'peak' herbicide concentration often occurs during one of these runoff events. Herbicide concentrations in rivers are affected by a number of factors, including herbicide use patterns within the associated basin....
Iron reduction in the sediments of a hydrocarbon-contaminated aquifer
M.E. Tuccillo, I.M. Cozzarelli, J.S. Herman
1999, Applied Geochemistry (14) 655-667
Sediments sampled at a hydrocarbon-contaminated, glacial-outwash, sandy aquifer near Bemidji, Minnesota, were analyzed for sediment-associated Fe with several techniques. Extraction with 0.5 M HCl dissolved poorly crystalline Fe oxides and small amounts of Fe in crystalline Fe oxides, and extracted Fe from phyllosilicates. Use...
A spatially distributed energy balance snowmelt model for application in mountain basins
D. Marks, J. Domingo, D. Susong, T. Link, D. Garen
1999, Hydrological Processes (13) 1935-1959
Snowmelt is the principal source for soil moisture, ground-water re-charge, and stream-flow in mountainous regions of the western US, Canada, and other similar regions of the world. Information on the timing, magnitude, and contributing area of melt under variable or changing climate conditions is required...
