Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 4094
Scales in chemical hydrogeology: A historical perspective
No abstract available.
Authors
W. Back, Mary Jo Baedecker, W. Wood
Seasonal relationships between planktonic microorganisms and dissolved organic material in an alpine stream
The relationships between the abundance and activity of planktonic, heterotrophic microorganisms and the quantity and characteristics of dissolved organic carbon (DOC) in a Rocky Mountain stream were evaluated. Peak values of glucose uptake, 2.1 nmol L−1 hr−1, and glucose concentration, 333 nM, occurred during spring snowmelt when the water temperature was 4.0°C and the DOC concentration was great
Authors
Diane M. McKnight, R. L. Smith, R.A. Harnish, C.L. Miller, K.E. Bencala
Manganese minerals and associated fine particulates in the streambed of Pinal Creek, Arizona, U.S.A.: a mining-related acid drainage problem
The Pinal creek drainage basin in Arizona is a good example of the principal non-coal source of mining-related acid drainage in the U.S.A., namely copper mining. Infiltration of drainage waters from mining and ore refining has created an acid groundwater plume that has reacted with calcite during passage through the alluvium, thereby becoming less acid. Where O2 is present and the water is partial
Authors
Carol J. Lind, J. D. Hem
Tidal, Residual, Intertidal Mudflat (TRIM) Model and its Applications to San Francisco Bay, California
A numerical model using a semi-implicit finite-difference method for solving the two-dimensional shallow-water equations is presented. The gradient of the water surface elevation in the momentum equations and the velocity divergence in the continuity equation are finite-differenced implicitly, the remaining terms are finite-differenced explicitly. The convective terms are treated using an Eulerian
Authors
R. T. Cheng, V. Casulli, J. W. Gartner
Effects of small-scale vertical variations in well-screen inflow rates and concentrations of organic compounds on the collection of representative ground-water-quality samples
Because a water sample collected from a well is an integration of water from different depths along the well screen, measured concentrations can be biased if analyte concentrations are not uniform along the length of the well screen. The resulting concentration in the sample, therefore, is a function of variations in well-screen inflow rate and analyte concentration with depth. A multiport sampler
Authors
Jacob Gibs, G. Allan Brown, Kenneth S. Turner, Cecilia L. MacLeod, James Jelinski, Susan A. Koehnlein
Surface chemistry of ferrihydrite: Part 1. EXAFS studies of the geometry of coprecipitated and adsorbed arsenate
EXAFS spectra were collected on both the As and Fe K-edges from samples of two-line ferrihydrite with adsorbed (ADS) and coprecipitated (CPT) arsenate prepared over a range of conditions and arsenate surface coverages. Spectra also were collected for arsenate adsorbed on the surfaces of three FeOOH crystalline polymorphs, α (goethite), β (akaganeite), and γ (lepidocrocite), and as a free ion in aq
Authors
G.A. Waychunas, B.A. Rea, C. C. Fuller, J.A. Davis
Effect of treated-sewage contamination upon bacterial energy charge, adenine nucleotides, and DNA content in a sandy aquifer on Cape Cod
Changes in adenylate energy charge (ECA) and in total adenine nucleotides (AT) and DNA content (both normalized to the abundance of free-living, groundwater bacteria) in response to carbon loading were determined for a laboratory-grown culture and for a contaminated aquifer. The latter study involved a 3-km-long transect through a contaminant plume resulting from continued on-land discharge of sec
Authors
David W. Metge, Myron H. Brooks, Richard L. Smith, Ronald W. Harvey
The role of water exchange between a stream channel and its hyporheic zone in nitrogen cycling at the terrestrial-aquatic interface
The subsurface riparian zone was examined as an ecotone with two interfaces. Inland is a terrestrial boundary, where transport of water and dissolved solutes is toward the channel and controlled by watershed hydrology. Streamside is an aquatic boundary, where exchange of surface water and dissolved solutes is bi-directional and flux is strongly influenced by channel hydraulics. Streamside, bi-dire
Authors
F.J. Triska, J.H. Duff, R. J. Avanzino
A finite-volume Eulerian-Lagrangian Localized Adjoint Method for solution of the advection-dispersion equation
A new mass-conservative method for solution of the one-dimensional advection-dispersion equation is derived and discussed. Test results demonstrate that the finite-volume Eulerian-Lagrangian localized adjoint method (FVELLAM) outperforms standard finite-difference methods, in terms of accuracy and efficiency, for solute transport problems that are dominated by advection. For dispersion-dominated p
Authors
R. W. Healy, T.F. Russell
Spatial variability of triazine herbicides in the Lower Mississippi River
No abstract available.
Authors
J. A. Moody, D. A. Goolsby
Effects of climatic variations over 11 years on nitrate-nitrogen concentrations in the Raccoon River, Iowa
Nitrate-nitrogen (NO3-N) concentrations at public water supply intakes on the Des Moines and Raccoon Rivers in Iowa exceeded the maximum contaminant level (MCL) of 10 mg L-1 for public water supplies established by the USEPA for extended periods of time from March through early August 1990. The excessive NO3-N levels followed 2 yr of less-than normal precipitation in 1988 and 1989. The largest dai
Authors
K.J. Lucey, D. A. Goolsby
Assessing the effect of pesticides in agricultural runoff on aquatic life in the Sangamon River near Monticello, Illinois
Stream-water samples collected from a midwest stream, following a thunderstorm during May 1991 were toxic to water fleas (Ceriodaphnia dubia), but not fathead minnows (Pimephales promelas), or a bacterium (Photobacterium phosphoreum) or green alga (Selenastrum capricornutum). It was unlikely that the toxicity to the water fleas was caused by herbicides, but it may have been caused by insecticides.
Authors
R.H. Coupe, M.S. Henebry, M.R. Branham