Surface complexation model of uranyl sorption on Georgia kaolinite
T.E. Payne, J.A. Davis, G.R. Lumpkin, R. Chisari, T.D. Waite
2004, Applied Clay Science (26) 151-162
The adsorption of uranyl on standard Georgia kaolinites (KGa-1 and KGa-1B) was studied as a function of pH (3–10), total U (1 and 10 μmol/l), and mass loading of clay (4 and 40 g/l). The uptake of uranyl in air-equilibrated systems increased with pH and reached...
Using fish communities to assess streams in Romania: Initial development of an index of biotic integrity
P. L. Angermeier, G. Davideanu
2004, Hydrobiologia (511) 65-78
Multimetric biotic indices increasingly are used to complement physicochemical data in assessments of stream quality. We initiated development of multimetric indices, based on fish communities, to assess biotic integrity of streams in two physiographic regions of central Romania. Unlike previous efforts to develop such indices for European streams, our metrics...
Food web pathway determines how selenium affects aquatic ecosystems: A San francisco Bay case study
A.R. Stewart, S. N. Luoma, C.E. Schlekat, M.A. Doblin, K.A. Hieb
2004, Environmental Science & Technology (38) 4519-4526
Chemical contaminants disrupt ecosystems, but specific effects may be under-appreciated when poorly known processes such as uptake mechanisms, uptake via diet, food preferences, and food web dynamics are influential. Here we show that a combination of food web structure and the physiology of trace element accumulation explain why some species...
Calculation of individual isotope equilibrium constants for geochemical reactions
D.C. Thorstenson, D.L. Parkhurst
2004, Geochimica et Cosmochimica Acta (68) 2449-2465
Theory is derived from the work of Urey (Urey H. C. [1947] The thermodynamic properties of isotopic substances. J. Chem. Soc. 562–581) to calculate equilibrium constants commonly used in geochemical equilibrium and reaction-transport models for reactions of individual isotopic species. Urey showed that equilibrium constants of isotope exchange reactions for molecules...
Ground water chlorinated ethenes in tree trunks: Case studies, influence of recharge, and potential degradation mechanism
D.A. Vroblesky, B.D. Clinton, J.M. Vose, C.C. Casey, G. J. Harvey, P. M. Bradley
2004, Ground Water Monitoring and Remediation (24) 124-138
Trichloroethene (TCE) was detected in cores of trees growing above TCE-contaminated ground at three sites: the Carswell Golf Course in Texas, Air Force Plant PJKS in Colorado, and Naval Weapons Station Charleston in South Carolina. This was true even when the depth to water was 7.9 m or when the...
Use of qualitative and quantitative information in neural networks for assessing agricultural chemical contamination of domestic wells
A. Mishra, C. Ray, D.W. Kolpin
2004, Journal of Hydrologic Engineering (9) 502-511
A neural network analysis of agrichemical occurrence in groundwater was conducted using data from a pilot study of 192 small-diameter drilled and driven wells and 115 dug and bored wells in Illinois, a regional reconnaissance network of 303 wells across 12 Midwestern states, and a study of 687 domestic wells...
Effects of nutrient enrichment on the decomposition of wood and associated microbial activity in streams
V. Gulis, A.D. Rosemond, K. Suberkropp, H.S. Weyers, J.P. Benstead
2004, Freshwater Biology (49) 1437-1447
1. We determined the effects of nutrient enrichment on wood decomposition rates and microbial activity during a 3-year study in two headwater streams at Coweeta Hydrologic Laboratory, NC, U.S.A. After a 1-year pretreatment period, one of the streams was continuously enriched with inorganic nutrients (nitrogen and phosphorus) for 2 years...
Persistence of pharmaceutical compounds and other organic wastewater contaminants in a conventional drinking-water-treatment plant
P. E. Stackelberg, E. T. Furlong, M. T. Meyer, S.D. Zaugg, A.K. Henderson, D.B. Reissman
2004, Science of the Total Environment (329) 99-113
In a study conducted by the US Geological Survey and the Centers for Disease Control and Prevention, 24 water samples were collected at selected locations within a drinking-water-treatment (DWT) facility and from the two streams that serve the facility to evaluate the potential for...
Using an ecoregion framework to analyze land-cover and land-use dynamics.
Alisa L. Gallant, Thomas R. Loveland, Terry L. Sohl, D.E. Napton
2004, Environmental Management (34) S89-S110
The United States has a highly varied landscape because of wide-ranging differences in combinations of climatic, geologic, edaphic, hydrologic, vegetative, and human management (land use) factors. Land uses are dynamic, with the types and rates of change dependent on a host of variables, including land accessibility, economic considerations, and the...
Baseflow contribution to nitrate-nitrogen export from a large, agricultural watershed, USA
K. Schilling, Y.-K. Zhang
2004, Journal of Hydrology (295) 305-316
Nitrate-nitrogen export from the Raccoon River watershed in west-central Iowa is among the highest in the United State and contributes to impairment of downstream water quality. We examined a rare long-term record of streamflow and nitrate concentration data (1972-2000) to evaluate annual and seasonal patterns of nitrate losses in streamflow...
Use of an electromagnetic seepage meter to investigate temporal variability in lake seepage
D.O. Rosenberry, R. H. Morin
2004, Ground Water (42) 68-77
A commercially available electromagnetic flowmeter is attached to a seepage cylinder to create an electromagnetic seepage meter (ESM) for automating measurement of fluxes across the sediment/water interface between ground water and surface water. The ESM is evaluated through its application at two lakes in New England, one where water seeps...
Comparison of 13 equations for determining evapotranspiration from a prairie wetland, Cottonwood Lake Area, North Dakota, USA
Donald O. Rosenberry, David L. Stannard, Thomas C. Winter, Margo L. Martinez
2004, Wetlands (24) 483-497
Evapotranspiration determined using the energy-budget method at a semi-permanent prairie-pothole wetland in east-central North Dakota, USA was compared with 12 other commonly used methods. The Priestley-Taylor and deBruin-Keijman methods compared best with the energy-budget values; mean differences were less than 0.1 mm d−1, and standard deviations were less than 0.3...
Microbial precipitation of dolomite in methanogenic groundwater
Jennifer A. Roberts, Philip C. Bennett, Luis A. Gonzalez, G.L. Macpherson, Kitty L. Milliken
2004, Geology (32) 277-280
We report low-temperature microbial precipitation of dolomite in dilute natural waters from both field and laboratory experiments. In a freshwater aquifer, microorganisms colonize basalt and nucleate nonstoichiometric dolomite on cell walls. In the laboratory, ordered dolomite formed at near-equilibrium conditions from groundwater with molar Mg:Ca ratios of <1; dolomite was...
Inhibition and enhancement of microbial surface colonization: the role of silicate composition
Jennifer A. Roberts
2004, Chemical Geology (212) 313-327
Classical treatment of cell attachment by models of filtration or coulombic attraction assumes that attachment of cells to mineral surfaces would be controlled by factors such as response to predation, collision efficiency, or coulombic attraction between the charged groups at the mineral and cell surfaces. In the study reported here,...
Monitored natural attenuation forum: A panel discussion
Bruce E. Rittmann, Fran Kremer, Barbara Bekins
2004, Remediation Journal (14) 153-158
No abstract available....
Potential exposure of larval and juvenile delta smelt to dissolved pesticides in the Sacramento-San Joaquin Delta, California
K.M. Kuivila, G.E. Moon
2004, American Fisheries Society Symposium 229-241
The San Francisco Estuary is critical habitat for delta smelt Hypomesus transpacificus, a fish whose abundance has declined greatly since 1983 and is now listed as threatened. In addition, the estuary receives drainage from the Central Valley, an urban and agricultural region with intense and diverse pesticide usage. One possible...
Importance of clay size minerals for Fe(III) respiration in a petroleum-contaminated aquifer
Evgenya S. Shelobolina, Robert T. Anderson, Yury N. Vodyanitskii, Anatolii V. Sivtsov, Richard Yuretich, Derek R. Lovely
2004, Geobiology (2) 67-76
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,...
Hydrology, metals, and aquatic physical habitat in the Upper Animas watershed, Colorado
R.T. Milhous
2004, Conference Paper, Watershed Management and Operations Management 2000
The Upper Animas River watershed in southwestern Colorado is a watershed with historic mining districts with many small mines and mills and a few larger mines and mills. The numbers of trout may be limited by high flows during the spring runoff period and by winter streamflows. In some locations...
Flood hydrology for Dry Creek, Lake County, Northwestern Montana
C. Parrett, R.D. Jarrett
2004, Conference Paper, Joint Conference on Water Resource Engineering and Water Resources Planning and Management 2000: Building Partnerships
Dry Creek drains about 22.6 square kilometers of rugged mountainous terrain upstream from Tabor Dam in the Mission Range near St. Ignatius, Montana. Because of uncertainty about plausible peak discharges and concerns regarding the ability of the Tabor Dam spillway to safely convey these discharges, the flood hydrology for Dry...
Water year 2004: Western water managers feel the heat
Thomas Pagano, Phil Pasteris, Michael D. Dettinger, Daniel Cayan, Kelly Redmond
2004, Eos, Earth and Space Science News (85) 385-393
This spring, a rare combination of exceptionally warm temperatures and near-record lack of precipitation in the western United States caused a rapid change in hydrologic conditions and an unexpectedly early onset of spring conditions. With much of the western U.S. already in its fifth year of drought, an above-average western snowpack...
Uranium adsorption on weathered schist - Intercomparison of modeling approaches
T.E. Payne, J.A. Davis, M. Ochs, M. Olin, C.J. Tweed
2004, Radiochimica Acta (92) 651-661
Experimental data for uranium adsorption on a complex weathered rock were simulated by twelve modelling teams from eight countries using surface complexation (SC) models. This intercomparison was part of an international project to evaluate the present capabilities and limitations of SC models in representing sorption by geologic materials. The models...
Benefits and impacts of road removal
T.A. Switalski, J.A. Bissonette, T.H. DeLuca, C.H. Luce, Mary Ann Madej
2004, Frontiers in Ecology and the Environment (2) 21-28
Road removal is being used to mitigate the physical and ecological impacts of roads and to restore both public and private lands. Although many federal and state agencies and private landowners have created protocols for road removal and priorities for restoration, research has not kept pace with the rate of...
Great Lakes clams find refuge from zebra mussels in restored, lake-connected marsh (Ohio)
S. Jerrine Nichols, Douglas A. Wilcox
2004, Ecological Restoration (22) 51-52
Since the early 1990s, more than 95 percent of the freshwater clams once found in Lake Erie have died due to the exotic zebara mussel (Dreissena polymorpha). Zebra mussels attach themselves to native clams in large numbers, impeding the ability of the clams to eat and burrow. However, in...
Hydrologic and hydraulic factors affecting passage of paddlefish through dams in the Upper Mississippi River
S. J. Zigler, M. R. Dewey, B.C. Knights, A.L. Runstrom, M.T. Steingraeber
2004, Transactions of the American Fisheries Society (133) 160-172
Populations of paddlefish Polyodon spathula have been adversely affected by dams that can block their movements. Unlike high-head dams that preclude fish passage (unless they are equipped with fishways), the dams on the upper Mississippi River are typically low-head dams with bottom release gates that may allow fish passage under...
Pocomoke Sound Sedimentary and Ecosystem History
Thomas M. Cronin
2004, Open-File Report 2004-1350
Summary of Results: Pocomoke Sound Sediment and Sediment Processes Transport of sediment from coastal marshes. Analyses of pollen and foraminifera from surface sediments in Pocomoke Sound suggest that neither the upstream forested wetlands nor coastal marshes bordering the sound have contributed appreciably to particulate matter in the 10- to 1000-micron size...
