Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 4094
Flexible digestion strategies and trace metal assimilation in marine bivalves
Pulse-chase experiments show that two marine bivalves take optimal advantage of different types of particulate food by varying food retention time in a flexible two-phase digestive system. For example, carbon is efficiently assimilated from bacteria by subjecting nearly all the ingested bacteria to prolonged digestion. Prolonging digestion also enhances assimilation of metals, many of which are to
Authors
Alan W. Decho, Samuel N. Luoma
Importance of dissolved sulfides and organic substances in controlling the chemical speciation of heavy metals in San Francisco Bay
No abstract available.
Authors
J.S. Kuwabara, C.C.Y. Chang, A.I. Khechfe, Y.R. Hunter
Regional differences in the origins of organic matter in the San Francisco Bay ecosystem: evidence from lipid biomarkers
No abstract available.
Authors
E. A. Canuel, J. E. Cloern
Interannual climate variability and snowpack in the western United States
An important part of the water supply in the western United States is derived from runoff fed by mountain snowmelt Snow accumulation responds to both precipitation and temperature variations, and forms an interesting climatic index, since it integrates these influences over the entire late fall-spring period. Here, effects of cool season climate variability upon snow water equivalent (SWE) over th
Authors
Daniel R. Cayan
Hydrologic evaluation methodology for estimating water movement through the unsaturated zone at commercial low-level radioactive waste disposal site
This report identifies key technical issues related to hydrologic assessment of water flow in the unsaturated zone at low-level radioactive waste (LLW) disposal facilities. In addition, a methodology for incorporating these issues in the performance assessment of proposed LLW disposal facilities is identified and evaluated. The issues discussed fall into four areas:Estimating the water balance at
Authors
P.D. Meyer, M.L. Rockhold, W.E. Nichols, G.W. Gee
Numerical evaluation of static-chamber measurements of soil-atmospheric gas exchange--Identification of physical processes
The exchange of gases between soil and atmosphere is an important process that affects atmospheric chemistry and therefore climate. The static-chamber method is the most commonly used technique for estimating the rate of that exchange. We examined the method under hypothetical field conditions where diffusion was the only mechanism for gas transport and the atmosphere outside the chamber was maint
Authors
Richard W. Healy, Robert G. Striegl, Thomas F. Russell, Gordon L. Hutchinson, Gerald P. Livingston
Uncertainties in assessing contaminant exposure from sediments
No abstract available.
Authors
S. N. Luoma, N.S. Fisher
Anaerobic mineralization of vinyl chloride in Fe(III)-reducing, aquifer sediments
Within anaerobic aquifer systems, reductive dehalogenation of polychlorinated ethenes commonly results in the accumulation of vinyl chloride, which is highly toxic and carcinogenic to humans. Anaerobic reduction of vinyl chloride is considered to be slow and incomplete. Here, we provide the first evidence for anaerobic oxidation of vinyl chloride under Fe(III)reducing conditions. Addition of chela
Authors
P. M. Bradley, F. H. Chapelle
Effects of sampling strategies on estimates of annual mean herbicide concentrations in midwestern rivers
The effects of 10 sampling strategies on estimates of annual mean concentrations of the herbicides atrazine, alachlor, and cyanazine in selected midwestern rivers were tested. The accuracy of the strategies was computed by comparing time-weighted annual mean herbicide concentrations calculated from water samples collected from 17 locations on midwestern rivers, with simulated annual mean concentra
Authors
W.A. Battaglin, L.E. Hay
Comparison of denitrification activity measurements in groundwater using cores and natural-gradient tracer tests
The transport of many solutes in groundwater is dependent upon the relative rates of physical flow and microbial metabolism. Quantifying rates of microbial processes under subsurface conditions is difficult and is most commonly approximated using laboratory studies with aquifer materials. In this study, we measured in situ rates of denitrification in a nitrate-contaminated aquifer using small-scal
Authors
R. L. Smith, S. P. Garabedian, M. H. Brooks
Reactive solute transport in streams: 1. Development of an equilibrium- based model
An equilibrium-based solute transport model is developed for the simulation of trace metal fate and transport in streams. The model is formed by coupling a solute transport model with a chemical equilibrium submodel based on MINTEQ. The solute transport model considers the physical processes of advection, dispersion, lateral inflow, and transient storage, while the equilibrium submodel considers t
Authors
Robert L. Runkel, Kenneth E. Bencala, Robert E. Broshears, Steven C. Chapra
Fate of linear alkylbenzene sulfonate in the Mississippi River
The 2 800-km reach of the Mississippi River between Minneapolis, MN, and New Orleans, LA, was examined for the occurrence and fate of linear alkylbenzene sulfonate (LAS), a common anionic surfactant found in municipal sewage effluents. River water and bottom sediment were sampled in the summer and fall of 1991 and in the spring of 1992. LAS was analyzed using solid-phase extraction/derivatization/
Authors
C.F. Tabor, L.B. Barber