Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 4094
Effect of water saturation in soil organic matter on the partition of organic compounds
No abstract available.
Authors
D.W. Rutherford, G.T. Chlou
A reconnaissance study of herbicides and their metabolites in surface water of the midwestern united states using immunoassay and gas chromatography/mass spectrometry
Preemergent herbicides and their metabolites, particularly atrazine, deethylatrazine, and metolachlor, persisted from 1989 to 1990 in the majority of rivers and streams in the midwestern United States. In spring, after the application of herbicides, the concentrations of atrazine, alachlor, and simazine were frequently 3-10 times greater than the U.S. Environmental Protection Agency maximum contam
Authors
E. Michael Thurman, D. A. Goolsby, M. T. Meyer, M. S. Mills, M.L. Pomes, Dana W. Kolpin
Modeling transport in transient ground-water flow: An unacknowledged approximation
During unsteady or transient ground-water flow, the fluid mass per unit volume of aquifer changes as the potentiometric head changes, and solute transport is affected by this change in fluid storage. Three widely applied numerical models of two-dimensional transport partially account for the effects of transient flow by removing terms corresponding to the fluid continuity equation from the transpo
Authors
Daniel J. Goode
A systematic approach to modelling the dynamic linkage of climate, physical catchment descriptors and hydrologic response components
No abstract available.
Authors
A.J. Jakeman, G.M. Hornberger, I.G. Littlewood, P.G. Whitehead, J. W. Harvey, K.E. Bencala
An improved method for field extraction and laboratory analysis of large, intact soil cores
Various methods have been proposed for the extraction of large, undisturbed soil cores and for subsequent analysis of fluid movement within the cores. The major problems associated with these methods are expense, cumbersome field extraction, and inadequate simulation of unsaturated flow conditions. A field and laboratory procedure is presented that is economical, convenient, and simulates unsatura
Authors
J.A. Tindall, K. Hemmen, J.F. Dowd
The aqueous photolysis of α-pinene in solution with humic acid
Terpenes are produced abundantly by environmental processes but are found in very low concentrations in natural waters. Aqueous photolysis of solutions containing α-pinene, a representative terpene, in the presence of humic acid resulted in degradation of the pinene. Comparison of this reaction to photolysis of α-pinene in the presence of methylene blue leads to the conclusion that the reactive pa
Authors
Marvin C. Goldberg, Kirkwood M. Cunningham, George R. Aiken, Eugene R. Weiner
Inhibition of existing denitrification enzyme activity by chloramphenicol
Chloramphenicol completely inhibited the activity of existing denitrification enzymes in acetylene-block incubations with (i) sediments from a nitrate-contaminated aquifer and (ii) a continuous culture of denitrifying groundwater bacteria. Control flasks with no antibiotic produced significant amounts of nitrous oxide in the same time period. Amendment with chloramphenicol after nitrous oxide prod
Authors
M. H. Brooks, R. L. Smith, D.L. Macalady
Consumption of freons CFC-11 and CFC-12 by anaerobic sediments and soils
A variety of anaerobic sediments and soils consumed CFC-11 (CFCl3) and CFC-12 (CF2Cl2). An aerobic soil did not. Active microbial metabolism was required for CFC-12 uptake in all of the sediments examined. CFC-11 uptake was faster in the presence of microbial activity, but reduced components in the sediments also resulted in nonenzymatic CFC-11 consumption in most instances. CFC-12 uptake in a cul
Authors
D. R. Lovley, J.C. Woodward
Aquatic insects as bioindicators of trace element contamination in cobble-bottom rivers and streams
In one river, Cu, Cd, Pb, and Zn were analysed in insects and in fine bed sediments over a 381-km reach downstream of a large copper mining complex. In another river, As contamination from a gold mine was assessed in insects and bed sediments over a 40-km reach. All insect taxa collected in contaminated river reaches had elevated whole-body trace element concentrations, but few species were distri
Authors
D.J. Cain, S. N. Luoma, J.L. Carter, S.V. Fend
Ground-water models cannot be validated
Ground-water models are embodiments of scientific hypotheses. As such, the models cannot be proven or validated, but only tested and invalidated. However, model testing and the evaluation of predictive errors lead to improved models and a better understanding of the problem at hand. In applying ground-water models to field problems, errors arise from conceptual deficiencies, numerical errors, and
Authors
Leonard F. Konikow, J. D. Bredehoeft
Chloride interference in the analysis of dissolved organic carbon by the wet oxidation method
The presence of Cl- in concentrations greater than 0.02 M is shown to interfere with the analysis of aqueous DOC concentrations by the wet oxidation method of analysis when a reaction time of 5 min is employed. Chloride competes with DOC for S2O82-, lowering the overall oxidation efficiency. The resulting HOCl from the oxidation of Cl- reacts with DOC, producing significant amounts of chlorinated
Authors
George R. Aiken
Discussion of "Aeration at Ohio River basin navigation dams"
No abstract available.
Authors
John S. Gulliver, Steven C. Wilhelms