Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 3787
Physiological considerations in applying laboratory-determined buoyant densities to predictions of bacterial and protozoan transport in groundwater: Results of in-situ and laboratory tests
Buoyant densities were determined for groundwater bacteria and microflagellates (protozoa) from a sandy aquifer (Cape Cod, MA) using two methods: (1) density-gradient centrifugation (DGC) and (2) Stoke's law approximations using sedimentation rates observed during natural-gradient injection and recovery tests. The dwarf (average cell size, 0.3 μm), unattached bacteria inhabiting a pristine zone j
Authors
R.W. Harvey, D.W. Metge, N. Kinner, N. Mayberry
Assessing hydrogeochemical heterogeneity in natural and constructed wetlands
While 'water quality function' is cited as an important wetland function to design for and preserve, we demonstrate that the scale at which hydrochemical samples are collected can significantly influence interpretations of biogeochemical processes in wetlands. Subsurface, chemical profiles for both nutrients and major ions were determined at a site in southwestern Wisconsin that contained areas of
Authors
R. J. Hunt, D. P. Krabbenhoft, M.P. Anderson
Differential cytochrome content and reductase activity in Geospirillum barnesii strain SeS3
The protein composition, cytochrome content, and reductase activity in the dissimilatory selenate-reducing bacterium Geospirillum barnesii strain SeS3, grown with thiosulfate, nitrate, selenate, or fumarate as the terminal electron acceptor, was investigated. Comparison of seven high-molecular-mass membrane proteins (105.3, 90.3, 82.6, 70.2, 67.4, 61.1, and 57.3 kDa) by SDS-PAGE showed that their
Authors
J.F. Stolz, T. Gugliuzza, Blum J. Switzer, R. Oremland, Murillo F. Martinez
Ambiguity in measuring matrix diffusion with single-well injection/recovery tracer tests
Single-well injection/recovery tracer tests are considered for use in characterizing and quantifying matrix diffusion in dual-porosity aquifers. Numerical modeling indicates that neither regional drift in homogeneous aquifers, nor heterogeneity in aquifers having no regional drift, nor hydrodynamic dispersion significantly affects these tests. However, when drift is coupled simultaneously with het
Authors
S.C. Lessoff, Leonard F. Konikow
Hydrogeologic framework of western Cape Cod, Massachusetts
The aquifer of western Cape Cod consists of several hydrogeologic units composed of sand, gravel, silt, and clay (fig. 1) that were deposited during the late Wisconsinan glaciation of New England. The aquifer is a shallow, unconfined hydrologic system in which ground-water flows radially outward from the apex of the ground-water mound near the center of the peninsula toward the coast (fig.2). The
Authors
John P. Masterson, Byron D. Stone, Donald A. Walter, Jennifer G. Savoie
Analysis of environmental data with censored observations
The potential threats to humans and to terrestrial and aquatic ecosystems from environmental contamination could depend on the sum of the concentrations of different chemicals. However, direct summation of environmental data is not generally feasible because it is common for some chemical concentrations to be recorded as being below the analytical reporting limit. This creates special problems in
Authors
S. Liu, J.-C. Lu, D.W. Kolpin, W.Q. Meeker
Concentration and transport of chlordane and nonachlor associated with suspended sediment in the Mississippi River, May 1988 to June 1990
Technical chlordane, a formerly widely used organochlorine pesticide, has become widespread in the environment. The distribution of technical chlordane in riverine environments may be due in part to resuspension and aqueous transport of contaminated bed sediment. To test this hypothesis, the Mississippi River was sampled for suspended sediment five times over a two- year period, at up to 17 sites
Authors
C.E. Rostad
Marine bacterial degradation of brominated methanes
Brominated methanes are ozone-depleting compounds whose natural sources include marine algae such as kelp. Brominated methane degradation by bacteria was investigated to address whether bacterial processes might effect net emission of these compounds to the atmosphere. Bacteria in seawater collected from California kelp beds degraded CH2Br2 but not CHBr3. Specific inhibitors showed that methanotro
Authors
K.D. Goodwin, M.E. Lidstrom, R.S. Oremland
Groundwater record of halocarbon transport by the Danube River
Groundwater dating studies have supported the concept that aquifers with low coefficients of dispersion may contain coherent records of past conditions in recharge areas. Groundwater records can provide unique information about natural or anthropogenic changes in the atmosphere and hydrosphere where long-term monitoring data are not available. Here we describe a 40-year record of halocarbon contam
Authors
J.K. Böhlke, K. Revesz, E. Busenberg, J. Deak, E. Deseo, M. Stute
The urban atmosphere as a non-point source for the transport of MTBE and other volatile organic compounds (VOCS) to shallow groundwater
Infiltration and dispersion (including molecular diffusion) can transport volatile organic compounds (VOCs) from urban air into shallow groundwater. The gasoline additive methyl-tert-butyl ether (MTBE) is of special interest because of its (1) current levels in some urban air, (2) strong partitioning from air into water, (3) resistance to degradation, (4) use as an octane-booster since the 1970s,
Authors
J. F. Pankow, N.R. Thomson, Richard L. Johnson, A. L. Baehr, J.S. Zogorski
Bacterial oxidation of methyl bromide in fumigated agricultural soils
The oxidation of [14C]methyl bromide ([14C]MeBr) to 14CO2 was measured in field experiments with soils collected from two strawberry plots fumigated with mixtures of MeBr and chloropicrin (CCl3NO2). Although these fumigants are considered potent biocides, we found that the highest rates of MeBr oxidation occurred 1 to 2 days after injection when the fields were tarped, rather than before or severa
Authors
L.G. Miller, T.L. Connell, J.R. Guidetti, R.S. Oremland
Effects of exchanged cation and layer charge on the sorption of water and EGME vapors on montmorillonite clays
The effects of exchanged cation and layer charge on the sorption of water and ethylene glycol monoethyl ether (EGME) vapors on montmorillonite have been studied on SAz-1 and SWy-1 source clays, each exchanged respectively with Ca, Na, K, Cs and tetramethylammonium (TMA) cations. The corresponding lattice expansions were also determined, and the corresponding N2 adsorption data were provided for co
Authors
Cary T. Chiou, David W. Rutherford