Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 3787
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
The determination and fate of unstable constituents of contaminated groundwater
No abstract available
Authors
M.J. Baedecker, M. Cozzarelli
Nitrate is a preferred electron acceptor for growth of freshwater selenate-respiring bacteria
An anaerobic, freshwater enrichment grew with either nitrate or selenate as an electron acceptor. With both ions present, nitrate reduction preceded selenate reduction. An isolate from the enrichment grew on either ion, but the presence of nitrate precluded the reduction of selenate. Stock cultures of denitrifiers grew anaerobically on nitrate but not on selenate.
Authors
Nisan A. Steinberg, Jodi Switzer Blum, Lawrence Hochstein, Ronald S. Oremland
Tensiometers: Theory, construction, and use
Standard tensiometers are used to measure matric potential as low as −870 cm of water in the unsaturated zone by creating a saturated hydraulic link between the soil water and a pressure sensor. The direction and, in some cases, quantity of water flux can be determined using multiple installations.A variety of commercial and fabricated tensiometers are commonly used. Saturated porous ceramic mater
Authors
D.I. Stannard
Synthetic organic agrochemicals in the lower Mississippi River and its major tributaries--Distribution, transport and fate
The Mississippi River and its major tributaries transport herbicides and their degradation products from agricultural areas in the mid-western U.S.A. These compounds include atrazine and its degradation products (desethyl- and desisopropylatrazine), simazine, cyanazine, metolachlor, and alachlor and its degradation products (2-chloro-2′,6′-diethylacetanilide 2-hydroxy-2′,6′-diethylacetanilide and
Authors
W. E. Pereira, C.E. Rostad, T.J. Leiker
Geochemical heterogeneity in a sand and gravel aquifer: Effect of sediment mineralogy and particle size on the sorption of chlorobenzenes
The effect of particle size, mineralogy and sediment organic carbon (SOC) on sorption of tetrachlorobenzene and pentachlorobenzene was evaluated using batch-isotherm experiments on sediment particle-size and mineralogical fractions from a sand and gravel aquifer, Cape Cod, Massachusetts. Concentration of SOC and sorption of chlorobenzenes increase with decreasing particle size. For a given particl
Authors
Larry B. Barber, E. Michael Thurman, Donald D. Runnells
Nitrogen-15 and carbon-13 NMR investigation of hydroxylamine-derivatized humic substances
No abstract available.
Authors
Kevin A. Thorn, Jeffrey B. Arterburn, Michael A. Mikita
Sampling vadose-zone water for a volatile organic compound at Picatinny Arsenal, New Jersey
A new method of collecting samples of unsaturated-zone water for quantitative analysis for a volatile organic compound, trichloroethene (TCE), was compared to three other, previously described sampling methodologies in the laboratory and in the field. In the laboratory, prepared water samples containing TCE in a known concentration (20 µg/L) were sampled repeatedly by using each of the four method
Authors
James A. Smith, H. Jean Cho, Peter R. Jaffe, Cecilia L. MacLeod, Susan A. Koehnlein