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Publications

Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).

Filter Total Items: 4093

Groundwater forecasting Groundwater forecasting

No abstract available.
Authors
Leonard F. Konikow, E.P. Patten

Pyrolysis-mass spectrometry/pattern recognition on a well-characterized suite of humic samples Pyrolysis-mass spectrometry/pattern recognition on a well-characterized suite of humic samples

A suite of well-characterized humic and fulvic acids of freshwater, soil and plant origin was subjected to pyrolysis-mass spectrometry and the resulting data were analyzed by pattern recognition and factor analysis. A factor analysis plot of the data shows that the humic acids and fulvic acids can be segregated into two distinct classes. Carbohydrate and phenolic components are more...
Authors
P. MacCarthy, S.J. DeLuca, K.J. Voorhees, Ronald L. Malcolm, E.M. Thurman

Error bounds in cascading regressions Error bounds in cascading regressions

Cascading regressions is a technique for predicting a value of a dependent variable when no paired measurements exist to perform a standard regression analysis. Biases in coefficients of a cascaded-regression line as well as error variance of points about the line are functions of the correlation coefficient between dependent and independent variables. Although this correlation cannot be...
Authors
M.R. Karlinger, B.M. Troutman

Origin of caves and other solution openings in the unsaturated (vadose) zone of carbonate rocks: A model for CO2 generation Origin of caves and other solution openings in the unsaturated (vadose) zone of carbonate rocks: A model for CO2 generation

The enigma that caves and other solution openings form in carbonate rocks at great depths below land surface rather than forming from the surface downward can be explained by the generation of CO2 within the aquifer system. In the proposed model, CO2 is generated by the oxidation of particulate and/or dissolved organic carbon that is transported from the land surface deep into the...
Authors
W.W. Wood

Simulation of steady-state flow in three-dimensional fracture networks using the boundary-element method Simulation of steady-state flow in three-dimensional fracture networks using the boundary-element method

An efficient method for simulating steady-state flow in three-dimensional fracture networks is formulated with the use of the boundary-element method. The host rock is considered to be impervious, and the fractures can be of any orientation and areal extent. The fractures are treated as surfaces where fluid movement is essentially two-dimensional. Fracture intersections are regarded as...
Authors
A.M. Shapiro, J. Andersson

Errors and parameter estimation in precipitation-runoff modeling: 1. Theory Errors and parameter estimation in precipitation-runoff modeling: 1. Theory

Errors in complex conceptual precipitation-runoff models may be analyzed by placing them into a statistical framework. This amounts to treating the errors as random variables and defining the probabilistic structure of the errors. By using such a framework, a large array of techniques, many of which have been presented in the statistical literature, becomes available to the modeler for...
Authors
Brent M. Troutman

Geochemical mass-balance relationships for selected ions in precipitation and stream water, Catoctin Mountains, Maryland Geochemical mass-balance relationships for selected ions in precipitation and stream water, Catoctin Mountains, Maryland

Results of a study of input/output mass balances for major ions based on the chemical composition of precipitation and stream-water, geochemical reactions with different loading rates of hydrogen ion, and watershed processes influencing the chemical character of stream-waters in two small watershed areas are reported with a view to predicting the effect of additions of acidic rain to the...
Authors
B. G. Katz, O.P. Bricker, M.M. Kennedy
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