Peter B McMahon (Former Employee)
Science and Products
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Filter Total Items: 118
Quantity and quality of ground-water discharge to the South Platte River, Denver to Fort Lupton, Colorado, August 1992 through July 1993 Quantity and quality of ground-water discharge to the South Platte River, Denver to Fort Lupton, Colorado, August 1992 through July 1993
Water-quality studies conducted by the Metro Wastewater Reclamation District have indicated that during low flow in segments of the South Platte River between Denver and Fort Lupton, concentrations of dissolved oxygen are less than minimum concen- trations set by the State of Colorado. Low dissolved-oxygen concentrations are observed in two reaches of the river-they are about 3.3 to 6.4...
Authors
P.B. McMahon, K.J. Lull, K.F. Dennehy, J.A. Collins
Effects of carbon and nitrate on denitrification in bottom sediments of an effluent-dominated river Effects of carbon and nitrate on denitrification in bottom sediments of an effluent-dominated river
Nitrogen and carbon limitation of denitrification in the bed sediments of an effluent-dominated stream were investigated by quantifying the effects of nitrate and glucose additions on the rate of sediment N2O production. Bed sediment samples were collected from a 30-km stretch of the South Platte River where up to 95% of the base flow discharge consists of effluent from a water treatment...
Authors
P. M. Bradley, P.B. McMahon, F. Chapelle
Effect of atrazine on potential denitrification in aquifer sediments Effect of atrazine on potential denitrification in aquifer sediments
Agriculturaf use of fertilizers and herbicides has often resulted in nitrate and atrazine contamination of the shallow aquifers that underlay cultivated fields. In several cases, the concentrations of atrazine and nitrate dissolved in ground water are positively correlated (Spalding ef al., 1979; Chen and Druliner, 1987; Spalding et al., 1989). Because simultaneous application of nitrate
Authors
P. M. Bradley, F. Chapelle, M.L. Jagucki, P.B. McMahon
Atrazine mineralization potential of alluvial-aquifer sediments under aerobic conditions Atrazine mineralization potential of alluvial-aquifer sediments under aerobic conditions
No abstract available.
Authors
P.B. McMahon, F. Chapelle, M.L. Jagucki
Role of microbial processes in linking sandstone diagenesis with organic-rich clays Role of microbial processes in linking sandstone diagenesis with organic-rich clays
Numerous chemical reactions within clay sequences have been proposed to produce dissolved material for diagenesis of deeply-buried sands. However, reactions responsible for solubilizing inorganic and organic constituents in clays at intermediate depths, and their importance to sandstone diagenesis, have not been evaluated. Results from this study show that the processes of microbial...
Authors
P.B. McMahon, F. Chapelle, W. Falls, P. M. Bradley
Geochemistry of dissolved inorganic carbon in a Coastal Plain aquifer. 2. Modeling carbon sources, sinks, and δ13C evolution Geochemistry of dissolved inorganic carbon in a Coastal Plain aquifer. 2. Modeling carbon sources, sinks, and δ13C evolution
Stable isotope data for dissolved inorganic carbon (DIC), carbonate shell material and cements, and microbial CO2 were combined with organic and inorganic chemical data from aquifer and confining-bed pore waters to construct geochemical reaction models along a flowpath in the Black Creek aquifer of South Carolina. Carbon-isotope fractionation between DIC and precipitating cements was...
Authors
Peter McMahon, Francis Chapelle
Science and Products
Filter Total Items: 14
No Result Found
Filter Total Items: 118
Quantity and quality of ground-water discharge to the South Platte River, Denver to Fort Lupton, Colorado, August 1992 through July 1993 Quantity and quality of ground-water discharge to the South Platte River, Denver to Fort Lupton, Colorado, August 1992 through July 1993
Water-quality studies conducted by the Metro Wastewater Reclamation District have indicated that during low flow in segments of the South Platte River between Denver and Fort Lupton, concentrations of dissolved oxygen are less than minimum concen- trations set by the State of Colorado. Low dissolved-oxygen concentrations are observed in two reaches of the river-they are about 3.3 to 6.4...
Authors
P.B. McMahon, K.J. Lull, K.F. Dennehy, J.A. Collins
Effects of carbon and nitrate on denitrification in bottom sediments of an effluent-dominated river Effects of carbon and nitrate on denitrification in bottom sediments of an effluent-dominated river
Nitrogen and carbon limitation of denitrification in the bed sediments of an effluent-dominated stream were investigated by quantifying the effects of nitrate and glucose additions on the rate of sediment N2O production. Bed sediment samples were collected from a 30-km stretch of the South Platte River where up to 95% of the base flow discharge consists of effluent from a water treatment...
Authors
P. M. Bradley, P.B. McMahon, F. Chapelle
Effect of atrazine on potential denitrification in aquifer sediments Effect of atrazine on potential denitrification in aquifer sediments
Agriculturaf use of fertilizers and herbicides has often resulted in nitrate and atrazine contamination of the shallow aquifers that underlay cultivated fields. In several cases, the concentrations of atrazine and nitrate dissolved in ground water are positively correlated (Spalding ef al., 1979; Chen and Druliner, 1987; Spalding et al., 1989). Because simultaneous application of nitrate
Authors
P. M. Bradley, F. Chapelle, M.L. Jagucki, P.B. McMahon
Atrazine mineralization potential of alluvial-aquifer sediments under aerobic conditions Atrazine mineralization potential of alluvial-aquifer sediments under aerobic conditions
No abstract available.
Authors
P.B. McMahon, F. Chapelle, M.L. Jagucki
Role of microbial processes in linking sandstone diagenesis with organic-rich clays Role of microbial processes in linking sandstone diagenesis with organic-rich clays
Numerous chemical reactions within clay sequences have been proposed to produce dissolved material for diagenesis of deeply-buried sands. However, reactions responsible for solubilizing inorganic and organic constituents in clays at intermediate depths, and their importance to sandstone diagenesis, have not been evaluated. Results from this study show that the processes of microbial...
Authors
P.B. McMahon, F. Chapelle, W. Falls, P. M. Bradley
Geochemistry of dissolved inorganic carbon in a Coastal Plain aquifer. 2. Modeling carbon sources, sinks, and δ13C evolution Geochemistry of dissolved inorganic carbon in a Coastal Plain aquifer. 2. Modeling carbon sources, sinks, and δ13C evolution
Stable isotope data for dissolved inorganic carbon (DIC), carbonate shell material and cements, and microbial CO2 were combined with organic and inorganic chemical data from aquifer and confining-bed pore waters to construct geochemical reaction models along a flowpath in the Black Creek aquifer of South Carolina. Carbon-isotope fractionation between DIC and precipitating cements was...
Authors
Peter McMahon, Francis Chapelle