Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 3746
Comparison of heat and bromide as ground-water tracers near streams
Heat and bromide were compared as tracers for examining stream/ground water exchanges along the middle reaches of the Santa Clara River, California, during a 10-hour surface water sodium bromide injection test. Three cross sections that comprise six shallow (
Authors
J. Constantz, M.H. Cox, G.W. Su
Subcellular compartmentalization of Cd and Zn in two bivalves. II. Significance of trophically available metal (TAM)
This paper examines how the subcellular partitioning of Cd and Zn in the bivalves Macoma balthica and Potamocorbula amurensis may affect the trophic transfer of metal to predators. Results show that the partitioning of metals to organelles, Œenzymes¹ and metallothioneins (MT) comprise a subcellular compartment containing trophically available metal (TAM; i.e. metal trophically available to predato
Authors
W.G. Wallace, Samuel N. Luoma
Modeling Np and Pu transport with a surface complexation model and spatially variant sorption capacities: Implications for reactive transport modeling and performance assessments of nuclear waste disposal sites
One-dimensional (1D) geochemical transport modeling is used to demonstrate the effects of speciation and sorption reactions on the ground-water transport of Np and Pu, two redox-sensitive elements. Earlier 1D simulations (Reardon, 1981) considered the kinetically limited dissolution of calcite and its effect on ion-exchange reactions (involving 90Sr, Ca, Na, Mg and K), and documented the spatial v
Authors
P. D. Glynn
Binding of mercury(II) to aquatic humic substances: Influence of pH and source of humic substances
Conditional distribution coefficients (KDOM‘) for Hg(II) binding to seven dissolved organic matter (DOM) isolates were measured at environmentally relevant ratios of Hg(II) to DOM. The results show that KDOM‘ values for different types of samples (humic acids, fulvic acids, hydrophobic acids) isolated from diverse aquatic environments were all within 1 order of magnitude (1022.5±1.0−1023.5±1.0 L k
Authors
M. Haitzer, G. R. Aiken, J. N. Ryan
Variations in flow and transport in thick desert vadose zones in response to paleoclimatic forcing (0-90 kyr): Field measurements, modeling, and uncertainties
An understanding of unsaturated flow and potential recharge in interdrainage semiarid and arid regions is critical for quantification of water resources and contaminant transport. We evaluated system response to paleoclimatic forcing using water potential and Cl profiles and modeling of nonisothermal liquid and vapor flow and Cl transport at semiarid (High Plains, Texas) and arid (Chihuahuan Deser
Authors
Bridget R. Scanlon, K. Keese, R.C. Reedy, Jirka Šimůnek, Brian J. Andraski
Characterization of lake water and ground water movement in the littoral zone of Williams Lake, a closed-basin lake in North central Minnesota
Williams Lake, Minnesota is a closed‐basin lake that is a flow‐through system with respect to ground water. Ground‐water input represents half of the annual water input and most of the chemical input to the lake. Chemical budgets indicate that the lake is a sink for calcium, yet surficial sediments contain little calcium carbonate. Sediment pore‐water samplers (peepers) were used to characterize s
Authors
P. F. Schuster, M.M. Reddy, J. W. LaBaugh, R.S. Parkhurst, D. O. Rosenberry, T. C. Winter, Ronald C. Antweiler, W.E. Dean
Application of ultrafiltration and stable isotopic amendments to field studies of mercury partitioning to filterable carbon in lake water and overland runoff
Results from pilot studies on colloidal phase transport of newly deposited mercury in lake water and overland runoff demonstrate that the combination of ultrafiltration, and stable isotope amendment techniques is a viable tool for the study of mercury partitioning to filterable carbon. Ultrafiltration mass balance calculations were generally excellent, averaging 97.3, 96.1 and 99.8% for dissolved
Authors
Christopher L. Babiarz, J.P. Hurley, D. P. Krabbenhoft, C. Gilmour, B.A. Branfireun
Surface complexation and precipitate geometry for aqueous Zn(II) sorption on ferrihydrite: II. XANES analysis and simulation
X-ray absorption near-edge spectroscopy (XANES) analysis of sorption complexes has the advantages of high sensitivity (10- to 20-fold greater than extended X-ray absorption fine structure [EXAFS] analysis) and relative ease and speed of data collection (because of the short k-space range). It is thus a potentially powerful tool for characterization of environmentally significant surface complexes
Authors
G.A. Waychunas, C. C. Fuller, J.A. Davis, J.J. Rehr
Subcellular compartmentalization of Cd and Zn in two bivalves. I. Significance of metal-sensitive fractions (MSF) and biologically detoxified metal (BDM)
Many aspects of metal accumulation in aquatic invertebrates (i.e. toxicity, tolerance and trophic transfer) can be understood by examining the subcellular partitioning of accumulated metal. In this paper, we use a compartmentalization approach to interpret the significance of metal, species and size dependence in the subcellular partitioning of Cd and Zn in the bivalves Macoma balthica and Potamoc
Authors
W.G. Wallace, B.-G. Lee, S. N. Luoma
Phytoplankton fuels Delta food web
Populations of certain fishes and invertebrates in the Sacramento-San Joaquin Delta have declined in abundance in recent decades and there is evidence that food supply is partly responsible. While many sources of organic matter in the Delta could be supporting fish populations indirectly through the food web (including aquatic vegetation and decaying organic matter from agricultural drainage), a c
Authors
Alan D. Jassby, James E. Cloern, A. B. Muller-Solger
Variability of isotope and major ion chemistry in the Allequash Basin, Wisconsin
As part of ongoing research conducted at one of the U.S. Geological Survey's Water, Energy, and Biogeochem-ical Budgets sites, work was undertaken to describe the spatial and temporal variability of stream and ground water isotopic composition and cation chemistry in the Trout Lake watershed, to relate the variability to the watershed flow system, and to identify the linkages of geochemical evolut
Authors
John F. Walker, Randall J. Hunt, Thomas D. Bullen, David P. Krabbenhoft, Carol Kendall
Summary of synoptic sampling and tracer-injection tests in the Alamosa River basin during high-flow conditions, June 1999: A sampling analysis report for modeling reactive transport of metals for the Summitville Mine, Colorado
No abstract available.
Authors
Roderick F. Ortiz, James W. Ball