Formation and transport of the sulfonic acid metabolites of alachlor and metolachlor in soil
D.S. Aga, E.M. Thurman
2001, Environmental Science & Technology (35) 2455-2460
Alachlor and metolachlor are dechlorinated and transformed into their corresponding ethane sulfonic acid (ESA) metabolites in soil. In a field-disappearance study, it was shown that alachlor ESA was formed at a faster rate and at concentrations 2−4 times higher than metolachlor ESA, conforming with the observed longer...
Topographic controls on the chemistry of subsurface stormflow
D.L. Welsch, C.N. Kroll, Jeffery J. McDonnell, Douglas A. Burns
2001, Hydrological Processes (15) 1925-1938
Models are needed that describe how topography and other watershed characteristics affect the chemical composition of runoff waters, yet little spatially distributed data exist to develop such models. A topographically driven flushing mechanism for nitrate (NO3-) and dissolved organic carbon has been described in recent literature; however, this mechanism has...
Hydrology of the coastal sabkhas of Abu Dhabi, United Arab Emirates
Ward E. Sanford, Warren W. Wood
2001, Hydrogeology Journal (9) 358-366
Water fluxes were estimated and a water budget developed for the land surface and a surficial 10-m-deep section of the coastal sabkhas that extend from the city of Abu Dhabi, United Arab Emirates, west to the border with Saudi Arabia. The fluxes were estimated on the basis of water levels...
Laboratory and field evaluations of the LISST-100 instrument for suspended particle size determinations
J. W. Gartner, R. T. Cheng, P.-F. Wang, K. Richter
2001, Marine Geology (175) 199-219
Advances in technology have resulted in a new instrument that is designed for in-situ determination of particle size spectra. Such an instrument that can measure undisturbed particle size distributions is much needed for sediment transport studies. The LISST-100 (Laser In-Situ Scattering and Transmissometry)...
Pollen assemblages as paleoenvironmental proxies in the Florida Everglades
Debra A. Willard, L. M. Weimer, W.L. Riegel
2001, Review of Palaeobotany and Palynology (113) 213-235
Analysis of 170 pollen assemblages from surface samples in eight vegetation types in the Florida Everglades indicates that these wetland sub-environments are distinguishable from the pollen record and that they are useful proxies for hydrologic and edaphic parameters. Vegetation types sampled include sawgrass marshes, cattail marshes, sloughs with floating aquatics,...
Timescales for nitrate contamination of spring waters, northern Florida, USA
B. G. Katz, J.K. Böhlke, H.D. Hornsby
2001, Chemical Geology (179) 167-186
Residence times of groundwater, discharging from springs in the middle Suwannee River Basin, were estimated using chlorofluorocarbons (CFCs), tritium (3H), and tritium/helium-3 (3H/3He) age-dating methods to assess the chronology of nitrate contamination of spring waters in northern Florida. During base-flow conditions for the Suwannee River in 1997–1999, 17 water samples...
Sulfate-reducing bacteria release barium and radium from naturally occurring radioactive material in oil-field barite
Elizabeth J.P. Phillips, E. R. Landa, T. Kraemer, R. Zielinski
2001, Geomicrobiology Journal (18) 167-182
Scale and sludge deposits formed during oil production can contain elevated levels of Ra, often coprecipitated with barium sulfate (barite). The potential for sulfate-reducing bacteria to release 226 Ra and Ba (a Ra analog) from oil-field barite was evaluated. The concentration of dissolved Ba increased when samples containing pipe scale,...
Influence of reactive sulfide (AVS) and supplementary food on Ag, Cd and Zn bioaccumulation in the marine polychaete Neanthes arenaceodentata
J.-S. Lee, B.-G. Lee, H. Yoo, C.-H. Koh, S. N. Luoma
2001, Marine Ecology Progress Series (216) 129-140
A laboratory bioassay determined the relative contribution of various pathways of Ag, Cd and Zn bioaccumulation in the marine polychaete Neanthes arenaceodentata exposed to moderately contaminated sediments. Juvenile worms were exposed for 25 d to experimental sediments containing 5 different reactive sulfide (acid volatile sulfides, AVS) concentrations (1 to 30...
Possible environmental factors underlying amphibian decline in eastern Puerto Rico: Analysis of U.S. government data archives
R.F. Stallard
2001, Conservation Biology (15) 943-953
The past three decades have seen major declines in populations of several species of amphibians at high elevations in eastern Puerto Rico, a region unique in the humid tropics because of the degree of environmental monitoring that has taken place through the efforts of U.S. government agencies. I examined changes...
Long-term changes in consentrations and flux fo nitrogen in the Mississippi River Basin, USA
D. A. Goolsby, W.A. Battaglin
2001, Hydrological Processes (15) 1209-1226
Current and historical data show that nitrogen concentrations and flux in the Mississippi River Basin have increased significantly during the past 100 years. Most of the increase observed in the lower Mississippi River has occurred since the early 1970s and is due almost entirely to an increase in nitrate. The...
Chemical and optical changes in freshwater dissolved organic matter exposed to solar radiation
C.L. Osburn, D.P. Morris, K. A. Thorn, R.E. Moeller
2001, Biogeochemistry (54) 251-278
We studied the chemical and optical changes inthe dissolved organic matter (DOM) from twofreshwater lakes and a Sphagnum bog afterexposure to solar radiation. Stable carbonisotopes and solid-state 13C-NMR spectraof DOM were used together with optical andchemical data to interpret results fromexperimental exposures of DOM to sunlight andfrom seasonal observations of...
Scleria lacustris (Cyperaceae), an aquatic and wetland sedge introduced to Florida
C.C. Jacono
2001, SIDA, Contributions to Botany (19) 1163-1170
A non-native species of Scleria, S. lacustris is reported from six counties and three major hydrologic regions in Florida. Biogeography and habitat in Florida are addressed. A description, key features and illustration are presented....
Mercury and methylmercury in water and sediment of the Sacramento River Basin, California
Joseph L. Domagalski
2001, Applied Geochemistry (16) 1677-1691
Mercury (Hg) and methylmercury (CH3Hg+) concentrations in streambed sediment and water were determined at 27 locations throughout the Sacramento River Basin, CA. Mercury in sediment was elevated at locations downstream of either Hg mining or Au mining activities where Hg was used in the recovery of Au. Methylmercury in sediment...
Streamflow forecasting using the modular modeling system and an object-user interface
A.E. Jeton
2001, Conference Paper, Proceedings of The Western Snow Conference
The U.S. Geological Survey (USGS), in cooperation with the Bureau of Reclamation (BOR), developed a computer program to provide a general framework needed to couple disparate environmental resource models and to manage the necessary data. The Object-User Interface (OUI) is a map-based interface for models and modeling data. It provides...
Pesticides in the hydrologic system - What do we know and what's next?
R. J. Gilliom
2001, Hydrological Processes (15) 3197-3201
Even though the occurrence and behaviour of pesticides in the environment have been studied for decades, water-quality managers and the public still demand more complete and consistent information, and there are many unanswered questions for environmental scientists. In many respects, the greatest potential for unintended adverse effects of pesticides is...
The geology and palynology of lower and Middle Pennsylvanian strata in the Western Kentucky Coal Field
C.F. Eble, S.F. Greb, D.A. Williams
2001, International Journal of Coal Geology (47) 189-206
The Western Kentucky Coal Field is the southern tip of the Eastern Interior, or Illinois Basin. Pennsylvanian rocks in this area, which include conglomerate, sandstone, shale, limestone and coal, were deposited primarily in coastal-deltaic settings at a time when western Kentucky was located close to the equator. This paper discusses...
Hydraulic head applications of flow logs in the study of heterogeneous aquifers
Frederick L. Paillet
2001, Ground Water (39) 667-675
Permeability profiles derived from high-resolution flow logs in heterogeneous aquifers provide a limited sample of the most permeable beds or fractures determining the hydraulic properties of those aquifers. This paper demonstrates that flow logs can also be used to infer the large-scale properties of aquifers surrounding boreholes. The analysis is...
River flow mass exponents with fractal channel networks and rainfall
B.M. Troutman, T.M. Over
2001, Advances in Water Resources (24) 967-989
An important problem in hydrologic science is understanding how river flow is influenced by rainfall properties and drainage basin characteristics. In this paper we consider one approach, the use of mass exponents, in examining the relation of river flow to rainfall and the channel network, which provides the primary conduit...
Developing a post-fire flood chronology and recurrence probability from alluvial stratigraphy in the Buffalo Creek watershed, Colorado, USA
J. G. Elliott, R. S. Parker
2001, Hydrological Processes (15) 3039-3051
Stratigraphic and geomorphic evidence indicate floods that occur soon after forest fires have been intermittent but common events in many mountainous areas during the past several thousand years. The magnitude and recurrence of these post-fire flood events reflects the joint probability between the recurrence of fires and the recurrence of...
Effect of basin physical characteristics on solute fluxes in nine alpine/subalpine basins, Colorado, USA
J.K. Sueker, D. W. Clow, J. N. Ryan, R.D. Jarrett
2001, Hydrological Processes (15) 2749-2769
Alpine/subalpine basins may exhibit substantial variability in solute fluxes despite many apparent similarities in basin characteristics. An evaluation of controls on spatial patterns in solute fluxes may allow development of predictive tools for assessing basin sensitivity to outside perturbations such as climate change or deposition of atmospheric pollutants. Relationships between...
Delineating a recharge area for a spring using numerical modeling, Monte Carlo techniques, and geochemical investigation
R. J. Hunt, J. J. Steuer, M.T.C. Mansor, T.D. Bullen
2001, Ground Water (39) 702-712
Recharge areas of spring systems can be hard to identify, but they can be critically important for protection of a spring resource. A recharge area for a spring complex in southern Wisconsin was delineated using a variety of complementary techniques. A telescopic mesh refinement (TMR) model was constructed from an...
Predictions of hydrothermal alteration within near-ridge oceanic crust from coordinated geochemical and fluid flow models
L.R. Wetzel, Jeff P. Raffensperger, E.L. Shock
2001, Journal of Volcanology and Geothermal Research (110) 319-342
Coordinated geochemical and hydrological calculations guide our understanding of the composition, fluid flow patterns, and thermal structure of near-ridge oceanic crust. The case study presented here illustrates geochemical and thermal changes taking place as oceanic crust ages from 0.2 to 1.0 Myr. Using a finite element code, we model fluid...
Rapid arsenite oxidation by Thermus aquaticus and Thermus thermophilus: Field and laboratory investigations
T.M. Gihring, G.K. Druschel, R. Blaine McCleskey, R.J. Hamers, J.F. Banfield
2001, Environmental Science & Technology (35) 3857-3862
Thermus aquaticus and Thermus thermophilus, common inhabitants of terrestrial hot springs and thermally polluted domestic and industrial waters, have been found to rapidly oxidize arsenite to arsenate. Field investigations at a hot spring in Yellowstone National Park revealed conserved total arsenic transport and rapid arsenite oxidation occurring within the drainage...
Comparison of soil infiltration rates in burned and unburned mountainous watersheds
D.A. Martin, J. A. Moody
2001, Hydrological Processes (15) 2893-2903
Steady-state infiltration measurements were made at mountainous sites in New Mexico and Colorado, USA, with volcanic and granitic soils after wildfires and at comparable unburned sites. We measured infiltration in the New Mexico volcanic soils under two vegetation types, ponderosa pine and mixed conifer, and in the Colorado granitic soils...
Differentiating nonpoint sources of deisopropylatrazine in surface water using discrimination diagrams
M. T. Meyer, E.M. Thurman, D. A. Goolsby
2001, Journal of Environmental Quality (30) 1836-1843
Pesticide degradates account for a significant portion of the pesticide load in surface water. Because pesticides with similar structures may degrade to the same degradate, it is important to distinguish between different sources of parent compounds that have different regulatory and environmental implications. A discrimination diagram, which is a sample...
