Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 3787
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
Big Soda Lake (Nevada). 3. Pelagic methanogenesis and anaerobic methane oxidation
In situ rates of methanogenesis and methane oxidation were measured in meromictic Big Soda Lake. Methane production was measured by the accumulation of methane in the headspaces of anaerobically sealed water samples; radiotracer was used to follow methane oxidation. Nearly all the methane oxidation occurred in the anoxic zones of the lake. Rates of anaerobic oxidation exceeded production at all de
Authors
Niels Iversen, Ronald S. Oremland, Michael J. Klug
Big Soda Lake (Nevada). 4. Vertical fluxes of particulate matter: Seasonality and variations across the chemocline
Vertical fluxes of particulate organic matter were measured with sediment traps above and below the chemocline of Big Soda Lake to define the seasonality of sinking losses from the mixolimnion and determine the effectiveness of the chemocline (pycnocline) as a barrier to the sinking of biogenic particles. Seasonality of sedimentation rates reflected seasonal changes in the community of autotrophs.
Authors
James E. Cloern, Brian E. Cole, Sally M. Wienke
Big Soda Lake (Nevada). 2. Pelagic sulfate reduction
The epilimnion of hypersaline, alkaline, meromictic Big Soda Lake contains an average 58 mmol sulfate liter−1 and 0.4 µmol dissolved iron liter−1. The monimolimnion, which is permanently anoxic, has a sulfide concentration ranging seasonally from 4 to 7 mmol liter−1. Depth profiles of sulfate reduction in the monimolimnion, assayed with a 35S tracer technique and in situ incubations, demonstrated
Authors
Richard L. Smith, Ronald S. Oremland
A wireline piston core barrel for sampling cohesionless sand and gravel below the water table
A coring device has been developed to obtain long and minimally disturbed samples of saturated cohesionless sand and gravel. The coring device, which includes a wireline and piston, was developed specifically for use during hollow-stem auger drilling but it also offers possibilities for cable tool and rotary drilling. The core barrel consists of an inner liner made of inexpensive aluminum or plast
Authors
Michael M. Zapico, Samuel Vales, John A. Cherry
Synthesis and stability of hetaerolite, ZnMn2O4, at 25°C
A precipitate of nearly pure hetaerolite, ZnMn2O4, a spinel-structured analog of hausmannite, Mn3O4, was prepared by an irreversible wprecipitation of zinc with manganese at 25°C. The synthesis technique entailed constant slow addition of a dilute solution of Mn2+ and Zn2+ chlorides having a Mn/Zn ratio of 2:1 to a reaction vessel that initially contained distilled deionized water, maintained at a
Authors
J. D. Hem, C. E. Roberson, C.J. Lind
Aqueous pyrite oxidation by dissolved oxygen and by ferric iron
Rates of aqueous, abiotic pyrite oxidation were measured in oxygen-saturated and anaerobic Fe(III)-saturated solutions with initial pH from 2 to 9. These studies included analyses of sulfite, thiosulfate, polythionates and sulfate and procedures for cleaning oxidation products from pyrite surfaces were evaluated. Pyrite oxidation in oxygen-saturated solutions produced (1) rates that were only slig
Authors
Carl O. Moses, D. Kirk Nordstrom, Janet S. Herman, Aaron L. Mills