Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 3746
Methods of analysis by the U.S. Geological Survey Organic Geochemistry Research Group: Determination of triazine and phenylurea herbicides and their degradation products in water using solid-phase extraction and liquid chromatography/mass spectrometry
An analytical method for the determination of 7 triazine and phenylurea herbicides and 12 of their degradation products in natural water samples using solid-phase extraction and liquid chromatography/mass spectrometry is presented in this report. Special consideration was given during the development of the method to prevent the formation of degradation products during the analysis. Filtered water
Authors
Edward Alan Lee, Alex P. Strahan, Earl Michael Thurman
Assessing ground-water vulnerability to contamination: Providing scientifically defensible information for decision makers
Throughout the United States increasing demands for safe drinking water and requirements to maintain healthy ecosystems are leading policy makers to ask complex social and scientific questions about how to assess and manage our water resources. This challenge becomes particularly difficult as policy and management objectives require scientific assessments of the potential for ground-water resource
Authors
Michael J. Focazio, Thomas E. Reilly, Michael G. Rupert, Dennis R. Helsel
Mechanisms of uranium interactions with hydroxyapatite: Implications for groundwater remediation
The speciation of U(VI) sorbed to synthetic hydroxyapatite was investigated using a combination of U LIII-edge XAS, synchrotron XRD, batch uptake measurements, and SEM-EDS. The mechanisms of U(VI) removal by apatite were determined in order to evaluate the feasibility of apatite-based in-situ permeable reactive barriers (PRBs). In batch U(VI) uptake experiments with synthetic hydroxyapatite (HA),
Authors
C. C. Fuller, J.R. Bargar, J.A. Davis, M.J. Piana
Choosing appropriate techniques for quantifying groundwater recharge
Various techniques are available to quantify recharge; however, choosing appropriate techniques is often difficult. Important considerations in choosing a technique include space/time scales, range, and reliability of recharge estimates based on different techniques; other factors may limit the application of particular techniques. The goal of the recharge study is important because it may dictate
Authors
Bridget R. Scanlon, Richard W. Healy, Peter G. Cook
A hydrogen-based subsurface microbial community dominated by methanogens
The search for extraterrestrial life may be facilitated if ecosystems can be found on Earth that exist under conditions analogous to those present on other planets or moons. It has been proposed, on the basis of geochemical and thermodynamic considerations, that geologically derived hydrogen might support subsurface microbial communities on Mars and Europa in which methanogens form the base of the
Authors
F. H. Chapelle, Kyle O'Neil, P. M. Bradley, B.A. Methe, S.A. Ciufo, L. L. Knobel, D. R. Lovley
Simulation of the mobility of metal-EDTA complexes in groundwater: The influence of contaminant metals
Reactive transport simulations were conducted to model chemical reactions between metal−EDTA (ethylenediaminetetraacetic acid) complexes during transport in a mildly acidic quartz−sand aquifer. Simulations were compared with the results of small-scale tracer tests wherein nickel−, zinc−, and calcium−EDTA complexes and free EDTA were injected into three distinct chemical zones of a plume of sewage-
Authors
J.C. Friedly, D.B. Kent, J.A. Davis
Leisingera methylohalidivorans gen. nov., sp. nov., a marine methylotroph that grows on methyl bromide
A marine methylotroph, designated strain MB2T, was isolated for its ability to grow on methyl bromide as a sole carbon and energy source. Methyl chloride and methyl iodide also supported growth, as did methionine and glycine betaine. A limited amount of growth was observed with dimethyl sulfide. Growth was also noted with unidentified components of the complex media marine broth 2216, yeast extrac
Authors
J.K. Schaefer, K.D. Goodwin, I.R. McDonald, J.C. Murrell, Ronald S. Oremland
Energy budget above a high-elevation subalpine forest in complex topography
Components of the energy budget were measured above a subalpine coniferous forest over two complete annual cycles. Sensible and latent heat fluxes were measured by eddy covariance. Bowen ratios ranged from 0.7 to 2.5 in the summer (June–September) depending upon the availability of soil water, but were considerably higher (∼3–6) during winter (December–March). Energy budget closure averaged better
Authors
A.A. Turnipseed, P.D. Blanken, D.E. Anderson, Russell K. Monson
Influence of fracture anisotropy on ground water ages and chemistry, Valley and Ridge province, Pennsylvania
Model ground water ages based on chlorofluorocarbons (CFCs) and tritium/helium-3 (3H/3He) data were obtained from two arrays of nested piezometers located on the north limb of an anticline in fractured sedimentary rocks in the Valley and Ridge geologic province of Pennsylvania. The fracture geometry of the gently east plunging fold is very regular and consists predominately of south dipping to sub
Authors
W. C. Burton, Niel Plummer, E. Busenberg, B.D. Lindsey, W.J. Gburek
Crosswell seismic investigation of hydraulically conductive, fracture bedrock near Mirror Lake, New Hampshire
Near Mirror Lake, New Hampshire (USA), hydraulically conductive, fractured bedrock was investigated with the crosswell seismic method to determine whether this method could provide any information about hydraulic conductivity between wells. To this end, crosswell seismic data, acoustic logs from boreholes, image logs from boreholes, and single borehole hydraulic tests were analyzed. The analysis s
Authors
K.J. Ellefsen, P. A. Hsieh, A.M. Shapiro
Thermocouple psychrometry
Thermocouple psychrometry is a technique that infers the water potential of the liquid phase of a sample from measurements within the vapor phase that is in equilibrium with the sample. The theoretical relation between water potential of the liquid phase and relative humidity of the vapor phase is given by the Kelvin equation Ψ = energy/volume = (RT/Vw) ln(p/po) [3.2.3–1]where ψ is water potential
Authors
Brian J. Andraski, Bridget R. Scanlon
Hydrogeologic framework, ground-water geochemistry, and assessment of nitrogen yield from base flow in two agricultural watersheds, Kent County, Maryland
Hydrostratigraphic and geochemical data collected in two adjacent watersheds on the Delmarva Peninsula, in Kent County, Maryland, indicate that shallow subsurface stratigraphy is an important factor that affects the concentrations of nitrogen in ground water discharging as stream base flow. The flux of nitrogen from shallow aquifers can contribute substantially to the eutrophication of streams and
Authors
L. J. Bachman, D.E. Krantz, John K. Böhlke