Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 3746
Water-quality and amphibian population data for Maryland, Washington, D.C., and Virginia, 2001-2004
Data on the chemical composition of water and on amphibian populations were collected at least annually from vernal pool and stream sites in Maryland, Washington, D.C., and Virginia, from 2001 through 2004. The data were collected as part of long-term monitoring projects of the Northeast Region of the Amphibian Research and Monitoring Initiative (ARMI) of the U.S. Geological Survey. Water samples
Authors
Karen C. Rice, Robin E. Jung
The influence of groundwater chemistry on arsenic concentrations and speciation in a quartz sand and gravel aquifer
We examined the chemical reactions influencing dissolved concentrations, speciation, and transport of naturally occurring arsenic (As) in a shallow, sand and gravel aquifer with distinct geochemical zones resulting from land disposal of dilute sewage effluent. The principal geochemical zones were: (1) the uncontaminated zone above the sewage plume [350 μM dissolved oxygen (DO), pH 5.9]; (2) the su
Authors
D.B. Kent, P.M. Fox
Modeling selenium bioaccumulation through arthropod food webs in San Francisco Bay, California, USA
Trophic transfer is the main process by which upper trophic level wildlife are exposed to selenium. Transfers through lower levels of a predator's food web thus can be instrumental in determining the threat of selenium in an ecosystem. Little is known about Se transfer through pelagic, zooplankton‐based food webs in San Francisco Bay ([SFB], CA, USA), which serve as an energy source for important
Authors
C.E. Schlekat, D.G. Purkerson, S. N. Luoma
Uranium adsorption on weathered schist - Intercomparison of modeling approaches
Experimental data for uranium adsorption on a complex weathered rock were simulated by twelve modelling teams from eight countries using surface complexation (SC) models. This intercomparison was part of an international project to evaluate the present capabilities and limitations of SC models in representing sorption by geologic materials. The models were assessed in terms of their predictive abi
Authors
T.E. Payne, J.A. Davis, M. Ochs, M. Olin, C.J. Tweed
Sensitivity to acidification of subalpine ponds and lakes in north-western Colorado
Although acidifying deposition in western North America is lower than in many parts of the world, many high-elevation ecosystems there are extremely sensitive to acidification. Previous studies determined that the Mount Zirkel Wilderness Area (MZWA) has the most acidic snowpack and aquatic ecosystems that are among the most sensitive in the region. In this study, spatial and temporal variability o
Authors
K. Campbell, E. Muths, J.T. Turk, P. S. Corn
Winter orographic precipitation ratios in the Sierra Nevada: Large-scale atmospheric circulations and hydrologic consequences
The extent to which winter precipitation is orographically enhanced within the Sierra Nevada of California varies from storm to storm, and season to season, from occasions when precipitation rates at low and high altitudes are almost the same to instances when precipitation rates at middle elevations (considered here) can be as much as 30 times more than at the base of the range. Analyses of large
Authors
M. Dettinger, K. Redmond, D. Cayan
Potential exposure of larval and juvenile delta smelt to dissolved pesticides in the Sacramento-San Joaquin Delta, California
The San Francisco Estuary is critical habitat for delta smelt Hypomesus transpacificus, a fish whose abundance has declined greatly since 1983 and is now listed as threatened. In addition, the estuary receives drainage from the Central Valley, an urban and agricultural region with intense and diverse pesticide usage. One possible factor of the delta smelt population decline is pesticide toxicity d
Authors
K.M. Kuivila, G.E. Moon
Hydrochemical tracers in the middle Rio Grande Basin, USA: 2. Calibration of a groundwater-flow model
The calibration of a groundwater model with the aid of hydrochemical data has demonstrated that low recharge rates in the Middle Rio Grande Basin may be responsible for a groundwater trough in the center of the basin and for a substantial amount of Rio Grande water in the regional flow system. Earlier models of the basin had difficulty reproducing these features without any hydrochemical data to c
Authors
W. E. Sanford, Niel Plummer, D. P. McAda, L. M. Bexfield, S. K. Anderholm
Food web pathway determines how selenium affects aquatic ecosystems: A San francisco Bay case study
Chemical contaminants disrupt ecosystems, but specific effects may be under-appreciated when poorly known processes such as uptake mechanisms, uptake via diet, food preferences, and food web dynamics are influential. Here we show that a combination of food web structure and the physiology of trace element accumulation explain why some species in San Francisco Bay are threatened by a relatively low
Authors
A.R. Stewart, S. N. Luoma, C.E. Schlekat, M.A. Doblin, K.A. Hieb
Approaches to surface complexation modeling of Uranium(VI) adsorption on aquifer sediments
Uranium(VI) adsorption onto aquifer sediments was studied in batch experiments as a function of pH and U(VI) and dissolved carbonate concentrations in artificial groundwater solutions. The sediments were collected from an alluvial aquifer at a location upgradient of contamination from a former uranium mill operation at Naturita, Colorado (USA). The ranges of aqueous chemical conditions used in the
Authors
J.A. Davis, D.E. Meece, M. Kohler, G.P. Curtis
Fractionation and characterization of organic matter in wastewater from a swine waste-retention basin
Organic matter in wastewater sampled from a swine waste-retention basin in Iowa was fractionated into 14 fractions on the basis of size (particulate, colloid, and dissolved); volatility; polarity (hydrophobic, transphilic, hydrophilic); acid, base, neutral characteristics; and precipitate or flocculates (floc) formation upon acidification. The compound-class composition of each of these fractions
Authors
Jerry A. Leenheer, Colleen E. Rostad
Questa baseline and pre-mining ground-water-quality investigation. 16. Quality assurance and quality control for water analyses
The Questa baseline and pre-mining ground-water quality investigation has the main objective of inferring the ground-water chemistry at an active mine site. Hence, existing ground-water chemistry and its quality assurance and quality control is of crucial importance to this study and a substantial effort was spent on this activity. Analyses of seventy-two blanks demonstrated that contamination fro
Authors
R. Blaine McCleskey, D. Kirk Nordstrom, Cheryl A. Naus