Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 4094
The developing framework of marine ecotoxicology: Pollutants as a variable in marine ecosystems?
Marine ecosystems include a subset in which at least some interrelated geochemical, biochemical, physiological, population and community characteristics are changed by pollutants. Moderate contamination is relatively widespread in coastal and estuarine ecosystems, so the subset of ecosystems with at least some processes affected could be relatively large. Pollutant influences have changed and will
Authors
Samuel N. Luoma
Phytoplankton bloom dynamics in coastal ecosystems: A review with some general lessons from sustained investigation of San Francisco Bay, California
Phytoplankton blooms are prominent features of biological variability in shallow coastal ecosystems such as estuaries, lagoons, bays, and tidal rivers. Long-term observation and research in San Francisco Bay illustrates some patterns of phytoplankton spatial and temporal variability and the underlying mechanisms of this variability. Blooms are events of rapid production and accumulation of phytopl
Authors
James E. Cloern
US Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Colorado Springs, Colorado, September 20-24, 1993
No abstract available.
Authors
D.W. Morganwalp, D. A. Aronson
A three-dimensional method-of-characteristics solute-transport model (MOC3D)
This report presents a model, MOC3D, that simulates three-dimensional solute transport in flowing ground water. The model computes changes in concentration of a single dissolved chemical constituent over time that are caused by advective transport, hydrodynamic dispersion (including both mechanical dispersion and diffusion), mixing (or dilution) from fluid sources, and mathematically simple chemic
Authors
Leonard F. Konikow, D.J. Goode, G.Z. Hornberger
Evaluating the reliability of the stream tracer approach to characterize stream-subsurface water exchange
Stream water was locally recharged into shallow groundwater flow paths that returned to the stream (hyporheic exchange) in St. Kevin Gulch, a Rocky Mountain stream in Colorado contaminated by acid mine drainage. Two approaches were used to characterize hyporheic exchange: sub-reach-scale measurement of hydraulic heads and hydraulic conductivity to compute streambed fluxes (hydrometric approach) an
Authors
Judson W. Harvey, Brian J. Wagner, Kenneth E. Bencala
Inferring shallow groundwater flow in saprolite and fractured rock using environmental tracers
The Ridge and Valley Province of eastern Tennessee is characterized by (1) substantial topographic relief, (2) folded and highly fractured rocks of various lithologies that have low primary permeability and porosity, and (3) a shallow residuum of medium permeability and high total porosity. Conceptual models of shallow groundwater flow and solute transport in this system have been developed but ar
Authors
P.G. Cook, D. K. Solomon, W. E. Sanford, E. Busenberg, Niel Plummer, R.J. Poreda
Integrated borehole logging methods for wellhead protection applications
Modeling of ground water infiltration and movement in the wellhead area is a critical part of an effective wellhead protection program. Such models depend on an accurate description of the aquifer in the wellhead area so that reliable estimates of contaminant travel times can be used in defining a protection area. Geophysical and hydraulic measurements in boreholes provide one of the most importan
Authors
Frederick L. Paillet, W.H. Pedler
Reactive solute transport in an acidic stream: Experimental pH increase and simulation of controls on pH, aluminum, and iron
Solute transport simulations quantitatively constrained hydrologic and geochemical hypotheses about field observations of a pH modification in an acid mine drainage stream. Carbonate chemistry, the formation of solid phases, and buffering interactions with the stream bed were important factors in explaining the behavior of pH, aluminum, and iron. The precipitation of microcrystalline gibbsite acco
Authors
R. E. Broshears, R.L. Runkel, B. A. Kimball, Diane M. McKnight, K.E. Bencala
Properties and variability of soil and trench fill at an arid waste-burial site
Arid sites commonly are assumed to be ideal for long-term isolation of wastes. Information on properties and variability of desert soils is limited, however, and little is known about how the natural site environment is altered by installation of a waste facility. During fall construction of two test trenches next to the waste facility on the Amargosa Desert near Beatty, NV, samples were collected
Authors
Brian J. Andraski
Occurrence of selected pesticides and their metabolites in near-surface aquifers of the midwestern United States
The occurrence and distribution of selected pesticides and their metabolites were investigated through the collection of 837 water-quality samples from 303 wells across the Midwest. Results of this study showed that five of the six most frequently detected compounds were pesticide metabolites. Thus, it was common for a metabolite to be found more frequently in groundwater than its parent compound.
Authors
D.W. Kolpin, Thurman E. Michael, D. A. Goolsby
Distributions and fate of chlorinated pesticides, biomarkers and polycyclic aromatic hydrocarbons in sediments along a contamination gradient from a point-source in San Francisco Bay, California
The distribution and fate of chlorinated pesticides, biomarkers, and polycyclic aromatic hydrocarbons (PAHs) in surficial sediments along a contamination gradient in the Lauritzen Canal and Richmond Harbor in San Francisco Bay was investigated. Compounds were identified and quantified using gas chromatography-ion trap mass spectrometry. Biomarkers and PAHs were derived primarily from weathered pet
Authors
W. E. Pereira, F. D. Hostettler, J. B. Rapp
Simulation of phosphate transport in sewage-contaminated groundwater, Cape Cod, Massachusetts
Sewage-contaminated groundwater currently discharges to Ashumet Pond, located on Cape Cod, Massachusetts. Phosphate concentrations as high as 60 μmol l−1 have been measured in groundwater entering Ashumet Pond, and there is concern that the rate of eutrophication could increase. Phosphate in the sewage plume is sorbed by aquifer sediment; the amount is a function of phosphate concentration and pH.
Authors
K.G. Stollenwerk