Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 3740
The distribution of, and relation among, mercury and methylmercury, organic carbon, carbonate, nitrogen and phosphorus, in periphyton of the south Florida ecosystem
Periphyton samples from Water Conservation Areas, Big Cypress National Preserve, and Everglades National Park in south Florida were analyzed for concentrations of total mercury, methylmercury, nitrogen, phosphorus, organic carbon, and inorganic carbon. Concentrations of total mercury in periphyton decrease slightly along a gradient from north‐to‐south. Both total mercury and methylmercury are posi
Authors
N.S. Simon, R. Spencer, T. Cox
Inhibition of precipitation and aggregation of metacinnabar (mercuric sulfide) by dissolved organic matter isolated from the Florida Everglades
Precipitation and aggregation of metacinnabar (black HgS) was inhibited in the presence of low concentrations (≥3 mg C/L) of humic fractions of dissolved organic matter (DOM) isolated from the Florida Everglades. At low Hg concentrations (≤5 × 10-8 M), DOM prevented the precipitation of metacinnabar. At moderate Hg concentrations (5 × 10-5 M), DOM inhibited the aggregation of colloidal metacinnaba
Authors
M. Ravichandran, G. R. Aiken, J. N. Ryan, M.M. Reddy
Distribution of microbial physiologic types in an aquifer contaminated by crude oil
We conducted a plume-scale study of the microbial ecology in the anaerobic portion of an aquifer contaminated by crude-oil compounds. The data provide insight into the patterns of ecological succession, microbial nutrient demands, and the relative importance of free-living versus attached microbial populations. The most probable number (MPN) method was used to characterize the spatial distribution
Authors
B.A. Bekins, E.M. Godsy, E. Warren
Nitrate in groundwater of the midwestern United States: A regional investigation on relations to land use and soil properties
The intense application of nitrogen-fertilizer to cropland in the midwestern United States has created concern about nitrate contamination of the region's aquifers. Since 1991, the US Geological Survey has used a network of 303 wells to investigate the regional distribution of nitrate in near-surface aquifers of the midwestern United States. Detailed land use and soil data were compiled within a 2
Authors
D. Kolpin, M. Burkart, D. Goolsby
Spatial variability of turbulent fluxes in the roughness sublayer of an even-aged pine forest
The spatial variability of turbulent flow statistics in the roughness sublayer (RSL) of a uniform even-aged 14 m (= h) tall loblolly pine forest was investigated experimentally. Using seven existing walkup towers at this stand, high frequency velocity, temperature, water vapour and carbon dioxide concentrations were measured at 15.5 m above the ground surface from October 6 to 10 in 1997. These se
Authors
G. Katul, C.-I. Hsieh, D. Bowling, K. Clark, N. Shurpali, A. Turnipseed, J. Albertson, K. Tu, D. Hollinger, B. M. Evans, B. Offerle, D. Anderson, D. Ellsworth, C. Vogel, R. Oren
Water-quality variability in San Francisco Bay: general patterns of change during 1997
The 1997 Annual Report is the fifth Annual Report from the Regional Monitoring Program for Trace Substances (RMP) and contains a comprehensive description of RMP results from the 1997 monitoring year. As in previous years, the report includes results from the Base Program (water, sediment, and bivalve monitoring) and results from Pilot and Special Studies completed in 1997, in addition to an updat
Authors
J. E. Cloern, B.E. Cole, J.L. Edmunds, J.I. Baylosis
Numerical simulation of vertical ground-water flux of the Rio Grande from ground-water temperature profiles, central New Mexico
An important gap in the understanding of the hydrology of the Middle Rio Grande Basin, central New Mexico, is the rate at which water from the Rio Grande recharges the Santa Fe Group aquifer system. Several methodologies-including use of the Glover-Balmer equation, flood pulses, and channel permeameters- have been applied to this problem in the Middle Rio Grande Basin. In the work presented here,
Authors
James R. Bartolino, Richard G. Niswonger
Bioaccumulation of metals by the bivalve Macoma balthica at a site in South San Francisco Bay between 1977 and 1997: Long-term trends and associated biological effects with changing pollutant loadings
No abstract available.
Authors
Michelle I. Hornberger, S. N. Luoma, D. Cain, F. Parchaso, C. Brown, R. Bouse, C.J. Wellise, John Thompson
Characterizing hydrology and the importance of ground-water discharge in natural and constructed wetlands
Although considered the most important component for the establishment and persistence of wetlands, hydrology has been hard to characterize and linkages between hydrology and other environmental conditions are often poorly understood. In this work, methods for characterizing a wetland’s hydrology from hydrographs were developed, and the importance of ground water to the physical and geochemical co
Authors
Randall J. Hunt, John F. Walker, David P. Krabbenhoft
Discharge of herbicides from the Mississippi River Basin to the Gulf of Mexico, 1991-97
No abstract available.
Authors
Gregory M. Clark, Donald A. Goolsby
Chemical data and lead isotopic compositions in stream-sediment samples from the Boulder River watershed, Jefferson County, Montana
Metal-mining related wastes in the Boulder River basin study area in northern Jefferson County, Montana, have been evaluated for their environmental effects as a part of the U.S. Geological Survey Abandoned Mine Lands Project. Many mine and prospect waste dumps, and mill wastes are located in the drainage basins of Basin Creek, Cataract Creek, and High Ore Creek, the three major tributaries to the
Authors
David L. Fey, Dan M. Unruh, Stan E. Church
User's guide to PHREEQC (Version 2): A computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations
PHREEQC version 2 is a computer program written in the C programming language that is designed to perform a wide variety of low-temperature aqueous geochemical calculations. PHREEQC is based on an ion-association aqueous model and has capabilities for (1) speciation and saturation-index calculations; (2) batch-reaction and one-dimensional (1D) transport calculations involving reversible reactions,
Authors
David L. Parkhurst, C.A.J. Appelo