Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
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Determining the distribution of hydraulic conductivity in a fractured limestone aquifer by simultaneous injection and geophysical logging
A field technique for assessing the vertical distribution of hydraulic conductivity in an aquifer was applied to a fractured carbonate formation in southeastern Nevada. The technique combines the simultaneous use of fluid injection and geophysical logging to measure in situ vertical distributions of fluid velocity and hydraulic head down the borehole; these data subsequently are analyzed to arrive
Authors
Roger H. Morin, A.E. Hess, Frederick L. Paillet
Sorption of vapors of some organic liquids on soil humic acid and its relation to partitioning of organic compounds in soil organic matter
Vapor sorption of water, ethanol, benzene, hexane, carbon tetrachloride, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene, and 1,2-dibromoethane on (Sanhedron) soil humic acid has been determined at room temperature. Isotherms for all organic liquids are highly linear over a wide range of relative pressure, characteristic of the partitioning (dissolution) of the organic compounds in s
Authors
G.T. Chlou, D. E. Kile, R. L. Malcolm
A statistical evaluation of formation disturbance produced by well- casing installation methods
Water-resources investigations concerned with contaminant transport through aquifers comprised of very loose, unconsolidated sediments have shown that small-scale variations in aquifer characteristics can significantly affect solute transport and dispersion. Commonly, measurement accuracy and resolution have been limited by a borehole environment consisting of an annulus of disturbed sediments pro
Authors
R. H. Morin, Denis R. LeBlanc, W.E. Teasdale
Hausmannite (Mn3O4) conversion to manganite (γ-MnOOH) in dilute oxalate solution
Oxalic acid retards the alteration of Mn3O4 to γ-MnOOH during aging at pH 7.4 ?? 0.2 in well-aerated, abiotic suspensions that contain 4.4 ?? 10-3 M total Mn. In solutions of 1.25 ?? 10-3 M oxalate and greater, about 15% of the initial Mn3O4 altered to ??-MnOOH by day 10, and in solutions of 6.7 ?? 10-4 M oxalate, about 45% altered to ??-MnOOH by day 67. Although precipitation continued through da
Authors
Carol J. Lind
Contamination of estuarine water, biota, and sediment by halogenated organic compounds: A field study
Studies conducted in the vicinity of an industrial outfall in the Calcasieu River estuary, Louisiana, have shown that water, bottom and suspended sediment, and four different species of biota are contaminated with halogenated organic compounds (HOC) including haloarenes. A "salting-out" effect in the estuary moderately enhanced the partitioning tendency of the contaminants into biota and sediments
Authors
W. E. Pereira, C.E. Rostad, C. T. Chiou, T.I. Brinton, L.B. Barber, D.K. Demcheck, C. R. Demas
Long-term fate of organic micropollutants in sewage-contaminated groundwater
No abstract available.
Authors
Larry B. Barber, M.P. Schroeder, E. Michael Thurman, Denis R. LeBlanc
Hydrogen concentrations as an indicator of the predominant terminal electron-accepting reactions in aquatic sediments
Factors controlling the concentration of dissolved hydrogen gas in anaerobic sedimentary environments were investigated. Results, presented here or previously, demonstrated that, in sediments, only microorganisms catalyze the oxidation of H2 coupled to the reduction of nitrate, Mn(IV), Fe(III), sulfate, or carbon dioxide. Theoretical considerations suggested that, at steady-state conditions, H2 co
Authors
D. R. Lovley, S. Goodwin
Fate of acetone in an outdoor model stream in southern Mississippi, U.S.A.
The fate of acetone in water was investigated in an outdoor model stream located in southern Mississippi, U.S.A. Acetone was injected continuously for 32 days resulting in small milligram-perliter concentrations in the stream. Rhodamine-WT dye was injected at the beginning and at the end of the study to determine the time-of-travel and dispersion characteristics of the stream. A 12-h injection of
Authors
R. E. Rathbun, D. W. Stephens, D.J. Shultz, D. Y. Tai
The feasibility of using sequential extraction techniques for As and Se in soils and sediments
Laboratory experiments were conducted with well-characterized minerals to test the applicability of selective extraction schemes for Se and As partitioning in soils and sediments. Two specific steps were tested: the reductive dissolution of amorphous iron oxides and the oxidation of organic material. Selenium and As associated with amorphous iron oxides were usually not found in solution after red
Authors
Karen A. Gruebel, James A. Davis, James O. Leckie
Groundwater flow and transport modeling
Deterministic, distributed-parameter, numerical simulation models for analyzing groundwater flow and transport problems have come to be used almost routinely during the past decade. A review of the theoretical basis and practical use of groundwater flow and solute transport models is used to illustrate the state-of-the-art. Because of errors and uncertainty in defining model parameters, models mus
Authors
Leonard F. Konikow, J.W. Mercer
Dichlorobenzene in ground water: Evidence for long-term persistence
Hydrologic and geochemical evidence were used to establish the long-term persistence of dichlorobenzene in ground water that has been contaminated from 50 years of rapid-infiltration sewage disposal. An extensive plume of dichlorobenzene extends more than 3,500 meters downgradient from the disposal beds, with concentrations of the combined isomers ranging from less than 0.01 to over 1.0 ??g/l. Bas
Authors
Larry B. Barber
Photolysis of rhodamine-WT dye
Photolysis of rhodamine-WT dye under natural sunlight conditions was determined by measuring the loss of fluorescence as a function of time. Rate coefficients at 30° north latitude ranged from 4.77 × 10−2 day−1 for summer to 3.16 × 10−2 day−2 for winter. Experimental coefficients were in good agreement with values calculated using a laboratory-determined value of the quantum yield.
Authors
D. Y. Tai, R. E. Rathbun