Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 4094
Reactive solute transport in streams: 2. Simulation of a pH modification experiment
We present an application of an equilibrium-based solute transport model to a pH-modification experiment conducted on the Snake River, an acidic, metal-rich stream located in the Rocky Mountains of Colorado. During the experiment, instream pH decreased from 4.2 to 3.2, causing a marked increase in dissolved iron concentrations. Model application requires specification of several parameters that ar
Authors
Robert L. Runkel, Diane M. McKnight, Kenneth E. Bencala, Steven C. Chapra
Observed and simulated movement of bank-storage water
Detailed hydrologic and water-chemistry data were collected that document the movement of bank-storage water during March 7-April 17, 1990, in an alluvial aquifer adjacent to the Cedar River, Iowa. Hydrologic data included 745 daily ground-water-level measurements from 27 observation wells. Water-chemistry data indicate that bank-storage water had smaller specific conductance and larger concentrat
Authors
P. J. Squillace
The relationships among three habitat scales and stream benthic invertebrate community structure
1. The relationships between three habitat scales and lotic invertebrate species composition were investigated for the 15 540 km2 Yakima River basin in south-central Washington, U.S.A.
2. The three spatial scales were sample (the sampled riffle), reach (a length of ten–twenty stream widths) and segment (a length of stream of nearly uniform slope and valley form having no change in stream order).
3
Authors
J.L. Carter, S.V. Fend, S.S. Kennelly
Near field receiving water monitoring of trace metals in clams (Macoma balthica) and sediments near the Palo Alto and San Jose/Sunnyvale Water Quality Control Plants in South San Francisco Bay: December 1994 - December 1995
No abstract available.
Authors
S. N. Luoma, D.J. Cain, C. Brown, M. Hornberger, R. Bouse
U.S. Geological Survey Nitrogen-Cycling Workshop: Denver, Colorado October 30 - November 2, 1995
No abstract available.
Authors
Frank J. Triska
Using a geographic information system and scanning technology to create high-resolution land-use data sets
A geographic information system (GIS) procedure was developed to compile low-altitude aerial photography, digitized data, and land-use data from U.S. Department of Agriculture Consolidated Farm Service Agency (CFSA) offices into a high-resolution (approximately 5 meters) land-use GIS data set. The aerial photography consisted of 35-mm slides which were scanned into tagged information file format (
Authors
Craig A. Harvey, Dana W. Kolpin, William A. Battaglin
Vulnerability of public drinking water supplies in New Jersey to pesticides
Beginning in 1993, Safe Drinking Water Act (SDWA) regulations required the 626 large community water systems in New Jersey to monitor their 2,600 wells and 45 surface-water intakes quarterly for 23 pesticides. Monitoring costs would increase consumers’ water bills by $6.4 million each year. The New Jersey Department of Environmental Protection (NJDEP) can waive monitoring requirements for wells or
Authors
Eric F. Vowinkel, R.M. Clawges, D.E. Buxton, D.A. Stedfast, J.B. Louis
Cadmium in the California Current system: Tracer of past and present upwelling
Over 100 samples were collected off the west coast of North America during 1991–1993 to determine the relation between wind‐driven upwelling and nearshore concentrations of dissolved silicate (Si), phosphate (P), and cadmium (Cd). Highly enriched in deep water offshore, these constituents are sensitive indicators of upwelling. Coastal water was sampled from the shore in January and June 1992 at 12
Authors
A. VanGeen, D.M. Husby
Use of 13C NMR and ftir for elucidation of degradation pathways during natural litter decomposition and composting I. early stage leaf degradation
Oxidative degradation of plant tissue leads to the formation of natural dissolved organic carbon (DOC) and humus. Infrared (IR) and 13C nuclear magnetic resonance (NMR) spectrometry have been used to elucidate the chemical reactions of the early stages of degradation that give rise to DOC derived from litter and compost. The results of this study indicate that oxidation of the lignin components of
Authors
R. L. Wershaw, J. A. Leenheer, K. R. Kennedy, T.I. Noyes
The long-term salinity field in San Francisco Bay
Data are presented on long-term salinity behaviour in San Francisco Bay, California. A two-level, width averaged model of the tidally averaged salinity and circulation has been written in order to interpret the long-term (days to decades) salinity variability. The model has been used to simulate daily averaged salinity in the upper and lower levels of a 51 segment discretization of the Bay over th
Authors
R.J. Uncles, D.H. Peterson
Kinetic and mineralogic controls on the evolution of groundwater chemistry and 87Sr/86Sr in a sandy silicate aquifer, northern Wisconsin, USA
Substantial flowpath-related variability of 87Sr/86Sr is observed in groundwaters collected from the Trout Lake watershed of northern Wisconsin. In the extensive shallow aquifer composed of sandy glacial outwash, groundwater is recharged either by seepage from lakes or by precipitation that infiltrates the inter-lake uplands. 87Sr/86Sr of groundwater derived mainly as seepage from a precipitation-
Authors
T.D. Bullen, D. P. Krabbenhoft, C. Kendall
Experimental investigation and modeling of uranium (VI) transport under variable chemical conditions
The transport of adsorbing and complexing metal ions in porous media was investigated with a series of batch and column experiments and with reactive solute transport modeling. Pulses of solutions containing U(VI) were pumped through columns filled with quartz grains, and the breakthrough of U(VI) was studied as a function of variable solution composition (pH, total U(VI) concentration, total fluo
Authors
M. Kohler, G.P. Curtis, D.B. Kent, J.A. Davis