Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 4094
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
Bacterial ethane formation from reduced, ethylated sulfur compounds in anoxic sediments
Trace levels of ethane were produced biologically in anoxic sediment slurries from five chemically different aquatic environments. Gases from these locations displayed biogenic characteristics, having 12C-enriched values of δ13CH4 (−62 to −86%.), δ13C2H6 (−35 to −55%.) and high ratios (720 to 140,000) of CH4[C2H6+ C3H8]. Endogenous production of ethane by slurries was inhibited by autoclaving or b
Authors
R.S. Oremland, Michael J. Whiticar, F.E. Strohmaier, R.P. Kiene
Accumulation and bioconcentration of polycyclic aromatic hydrocarbons in a nearshore estuarine environment near a Pensacola (Florida) creosote contamination site
Long-term accumulation of creosote wastes at a wood-preserving facility near Pensacola, Florida, has produced high levels of organic contamination of groundwaters near Pensacola Bay. Impacts of this contamination on the nearshore environment of the bay were examined by analysis of water, sediment and tissues of two mollusc species. One of the species (Thais haemastoma) was native to the study area
Authors
J. F. Elder, P.V. Dresler
Laboratory investigation of longitudinal dispersion in anisotropic porous media
In this study, laboratory experiments were used to investigate mechanisms that may cause anisotropy in the dispersion coefficient and to investigate the relation between anisotropy in hydraulic conductivity and anisotropy in longitudinal dispersion. Measurements of sodium chloride concentration (used as a tracer) were made at 105 in situ sampling locations in a new type of sand box designed to all
Authors
Stephen E. Silliman, Leonard F. Konikow, C.I. Voss
Discussion of "Volatilization rates of organic chemicals of public health concern"
No abstract available.
Authors
R.E. Rathburn, D. Y. Tai
Selective transport of hydrocarbons in the unsaturated zone due to aqueous and vapor phase partitioning
Long-term groundwater contamination can result from vapors and solutes emanating from organic liquids spilled in the unsaturated zone. The mathematical modeling analysis presented in this paper demonstrates for gasoline-range hydrocarbons, and other volatile organics commonly spilled, that diffusive transport in the unsaturated zone is a significant transport mechanism which can cause aqueous and
Authors
Arthur L. Baehr
Fracture characterization by means of attenuation and generation of tube waves in fractured crystalline rock at Mirror Lake, New Hampshire
Results are presented from experiments carried out in conjunction with the U. S. Geological Survey at the Hubbard Brook Experimental Forest near Mirror Lake, New Hampshire. The study focuses on our ability to obtain orientation and transmissivity estimates of naturally occurring fractures. The collected data set includes a four-offset hydrophone vertical seismic profile, full waveform acoustic log
Authors
E.L. Hardin, C.H. Cheng, F.L. Paillet, J.D. Mendelson
Rapid assay for microbially reducible ferric iron in aquatic sediments
The availability of ferric iron for microbial reduction as directly determined by the activity of iron-reducing organisms was compared with its availability as determined by a newly developed chemical assay for microbially reducible iron. The chemical assay was based on the reduction of poorly crystalline ferric iron by hydroxylamine under acidic conditions. There was a strong correlation between
Authors
Derek R. Lovely, Elizabeth J.P. Philips