Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 3787
Comment on "Horizontal aquifer movement in a theis-theim confined system" by Donald C. Helm
In a recent paper, Helm [1994] presents an analysis of horizontal aquifer movement induced by groundwater withdrawal from a confined aquifer in which fluid and grains are incompressible. The analysis considers the aquifer in isolation (ignoring overlying and underlying strata) and assumes that the aquifer deforms purely in the horizontal direction (with no vertical movement). Helm's solution for g
Authors
Paul A. Hsieh, Richard L. Cooley
Simulation of aerobic and anaerobic biodegradation processes at a crude oil spill site
A two-dimensional, multispecies reactive solute transport model with sequential aerobic and anaerobic degradation processes was developed and tested. The model was used to study the field-scale solute transport and degradation processes at the Bemidji, Minnesota, crude oil spill site. The simulations included the biodegradation of volatile and nonvolatile fractions of dissolved organic carbon by a
Authors
Hedeff I. Essaid, Barbara A. Bekins, E. Michael Godsy, Ean Warren, Mary Jo Baedecker, Isabelle M. Cozzarelli
Concentrations and mass transport of pesticides and organic contaminants in the Mississippi River and some of its tributaries, 1987-89 and 1991-92
No abstract available.
Authors
Wilfred E. Pereira, J. A. Moody, F. D. Hostettler, C.E. Rostad, T.J. Leiker
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; June 1993 through October 1994
No abstract available.
Authors
S. N. Luoma, D.J. Cain, C. L. Brown, Michelle I. Hornberger, R. M. Bouse-Schaenemann
Modeling hexavalent chromium reduction in groundwater in field-scale transport and laboratory batch experiments
A plausible and consistent model is developed to obtain a quantitative description of the gradual disappearance of hexavalent chromium (Cr(VI)) from groundwater in a small-scale field tracer test and in batch kinetic experiments using aquifer sediments under similar chemical conditions. The data exhibit three distinct timescales. Fast reduction occurs in well-stirred batch reactors in times much l
Authors
J.C. Friedly, J.A. Davis, D.B. Kent
An empirical model of the phytoplankton chlorophyll : carbon ratio-the conversion factor between productivity and growth rate
We present an empirical model that describes the ratio of phytoplankton chlorophyll a to carbon, Chl: C, as a function of temperature, daily irradiance, and nutrient-limited growth rate. Our model is based on 219 published measurements of algal cultures exposed to light-limited or nutrient-limited growth conditions. We illustrate an approach for using this estimator of Chl: C to calculate phytopla
Authors
James E. Cloern, Christian Grenz, Lisa Vidergar-Lucas
Use of a reactive gas transport model to determine rates of hydrocarbon biodegradation in unsaturated porous media
A mathematical model is presented that simulates the transport and reaction of any number of gaseous phase constituents (e.g. CO2, O2, N2, and hydrocarbons) in unsaturated porous media. The model was developed as part of a method to determine rates of hydrocarbon biodegradation associated with natural cleansing at petroleum product spill sites. The one-dimensional model can be applied to analyze d
Authors
Arthur L. Baehr, Ronald J. Baker
Evaluation of lipid-containing semipermeable membrane devices for monitoring organochlorine contaminants in the Upper Mississippi river
Organochlorine contaminants sequestered in lipid-containing semipermeable membrane devices (SPMDs) were compared to those found in tangential-flow ultrafilter permeates as part of a pilot study at 10 sites in the Upper Mississippi River system. Caged and feral fish from three primary sites were also analyzed for comparison. Concentrated organochlorine (OC) compounds were readily extracted from the
Authors
Geoffrey S. Ellis, Colleen E. Rostad, James N. Huckins, Christopher J. Schmitt, Patrick MacCarthy
Hydrogeology and geochemistry of acid mine drainage in ground water in the vicinity of Penn Mine and Camanche Reservoir, Calaveras County, California: First-year summary
Acid drainage from the Penn Mine in Calaveras County, California, has caused contamination of ground water between Mine Run Dam and Camanche Reservoir. The Penn Mine was first developed in the 1860's primarily for copper and later produced lesser amounts of zinc, lead, silver, and gold from steeply dipping massive sulfide lenses in metamorphic rocks. Surface disposal of sulfidic waste rock and tai
Authors
S. N. Hamlin, Charles N. Alpers
Hydrologic data from the lower Cedar River Basin, Iowa, 1989-91
Hydrologic data were collected from May 1989 through July 1991 from the Cedar River and the adjacent alluvial aquifer. The data were collected during various flow regimes of the river to evaluate the movement of agricultural chemicals between surface water and ground water. Water-quality samples from 34 surface-water sites and 95 ground-water sites were analyzed for 11 herbicides, 2 dealkylated at
Authors
P.M. Schulmeyer, K.K. Barnes, P. J. Squillace
Benthic macrofauna data for San Francisco Bay, California, September 1986
Benthic macrofauna were collected during September 1986 to evaluate locations for long-term monitoring stations as part of the U.S. Geological Survey Regional Effects Monitoring Program in San Francisco Bay, California. Three to ten replicate samples were collected with a modified Van Veen sampler (0.05 m2 area) at ten locations. One box core sample (0.06 m2 area) was collected at seven to the ten
Authors
Laurence E. Schemel, J.K. Thompson, J.G. Harmon, B. T. Yost
A computer program (MACPUMP) for interactive aquifer-test analysis
This report introduces MACPUMP (Version 1.0), an aquifer-test-analysis package for use with Macintosh4 computers. The report outlines the input- data format, describes the solutions encoded in the program, explains the menu-items, and offers a tutorial illustrating the use of the program. The package reads list-directed aquifer-test data from a file, plots the data to the screen, generates and plo
Authors
F. D. Day-Lewis, M.A. Person, Leonard F. Konikow