Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 4094
Effects of carbon dioxide variations in the unsaturated zone on water chemistry in a glacial-outwash aquifer
The research site at Otis Air Base, Cape Cod, Massachusetts, has been developed for hydrogeological and geochemical studies of sewage-effluent contaminated groundwater since 1982. Research of hydrologic properties, transport, and chemical and biological processes is ongoing, but the origin of background water chemistry has not been determined. The principal geochemical process giving rise to the o
Authors
R. W. Lee
Soil-water movement under natural-site and waste-site conditions: A multiple-year field study in the Mojave Desert, Nevada
Soil-water movement under natural-site and simulated waste-site conditions were compared by monitoring four experimental sites in the Mojave Desert, Nevada, during a 5-year period: one vegetated soil profile, one soil profile where vegetation was removed, and two nonvegetated test trenches. Precipitation ranged from 14 to 162 mm/yr. Temporal changes in water content measured by neutron probe were
Authors
Brian J. Andraski
Historical trends in organochlorine compounds in river basins identified using sediment cores from reservoirs
This study used chemical analyses of dated sediment cores from reservoirs to define historical trends in water quality in the influent river basins. This work applies techniques from paleolimnology to reservoirs, and in the process, highlights differences between sediment-core interpretations for reservoirs and natural lakes. Sediment cores were collected from six reservoirs in the central and sou
Authors
P. C. Van Metre, E. Callender, C. C. Fuller
Geochemical mole-balance modeling with uncertain data
Geochemical mole-balance models are sets of chemical reactions that quantitatively account for changes in the chemical and isotopic composition of water along a flow path. A revised mole-balance formulation that includes an uncertainty term for each chemical and isotopic datum is derived. The revised formulation is comprised of mole-balance equations for each element or element redox state, alkali
Authors
David L. Parkhurst
The design of sampling transects for characterizing water quality in estuaries
The high spatial variability of estuaries poses a challenge for characterizing estuarine water quality. This problem was examined by conducting monthly high-resolution transects for several water quality variables (chlorophyll a, suspended particulate matter and salinity) in San Francisco Bay (California, U.S.A.). Using these data, six different ways of choosing station locations along a transect,
Authors
A.D. Jassby, B.E. Cole, J. E. Cloern
Statistical modeling of agricultural chemical occurrence in midwestern rivers
Agricultural chemicals in surface water may constitute a human health risk or have adverse effects on aquatic life. Recent research on unregulated rivers in the midwestern USA documents that elevated concentrations of herbicides occur for 1-4 months following application in late spring and early summer. In contrast, nitrate concentrations in unregulated rivers are elevated during fall, winter, and
Authors
W.A. Battaglin, D. A. Goolsby
Kinetics of DCE and VC mineralization under methanogenic and Fe(III)- reducing conditions
The kinetics of anaerobic mineralization of DCE and VC under methanogenic and Fe(III)-reducing conditions as a function of dissolved contaminant concentration were evaluated. Microorganisms indigenous to creek bed sedi ments, where groundwater contaminated with chlorinated ethenes continuously discharges, demonstrated significant mineralization of DCE and VC under methanogenic and Fe(III)-reducing
Authors
P. M. Bradley, F. H. Chapelle
Response characteristics of DOC flushing in an alpine catchment
The spatial distribution of source areas and associated residence times of water in the catchment are significant factors controlling the annual cycles of dissolved organic carbon (DOC) concentration in Deer Creek (Summit County, Colorado). During spring snowmelt (April-August 1992), stream DOC concentrations increased with the rising limb of the hydrograph, peaked before maximum discharge, then d
Authors
E. W. Boyer, G.M. Hornberger, K.E. Bencala, Diane M. McKnight
Stream bed temperature profiles as indicators of percolation characteristics beneath arroyos in the middle Rio Grande Basin, USA
Stream bed temperature profiles were monitored continuously during water year 1990 and 1991 (WY90 and 91) in two New Mexico arroyos, similar in their meteorological features and dissimilar in their hydrological features. Stream bed temperature profiles between depths of 30 and 300 cm were examined to determine whether temporal changes in temperature profiles represent accurate indicators of the ti
Authors
J. Constantz, C. L. Thomas
Use of chemical and isotopic tracers to characterize the interactions between ground water and surface water in mantled karst
In the mantled karst terrane of northern Florida, the water quality of the Upper Floridan aquifer is influenced by the degree of connectivity between the aquifer and the surface. Chemical and isotopic analyses [18O/16O (δ18O), 2H/1H (δD), 13C/12C (δ13C), tritium (3H), and strontium‐87/strontium‐86 (87Sr/86Sr)] along with geochemical mass‐balance modeling were used to identify the dominant hydroche
Authors
B. G. Katz, T. B. Coplen, T.D. Bullen, J. Hal Davis
Microbial reduction of iodate
The different oxidation species of iodine have markedly different sorption properties. Hence, changes in iodine redox states can greatly affect the mobility of iodine in the environment. Although a major microbial role has been suggested in the past to account for these redox changes, little has been done to elucidate the responsible microorganisms or the mechanisms involved. In the work presented
Authors
T.B. Councell, E. R. Landa, D. R. Lovley