Peter B McMahon (Former Employee)
Science and Products
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Microbial production of organic acids in aquitard sediments and its role in aquifer geochemistry Microbial production of organic acids in aquitard sediments and its role in aquifer geochemistry
Microbial activity in aquifers plays an important part in the chemical evolution of ground water1–5. The most important terminal electron-accepting microbial processes in deeply buried anaerobic aquifers are iron reduction, sulphate reduction and methanogenesis5–8, each of which requires simple organic compounds or hydrogen (H2) as electron donors. Until now, the source of these...
Authors
P.B. McMahon, F. Chapelle
Geochemistry of dissolved inorganic carbon in a Coastal Plain aquifer. 1. Sulfate from confining beds as an oxidant in microbial CO2 production Geochemistry of dissolved inorganic carbon in a Coastal Plain aquifer. 1. Sulfate from confining beds as an oxidant in microbial CO2 production
A primary source of dissolved inorganic carbon (DIC) in the Black Creek aquifer of South Carolina is carbon dioxide produced by microbially mediated oxidation of sedimentary organic matter. Groundwater chemistry data indicate, however, that the available mass of inorganic electron acceptors (oxygen, Fe(III), and sulfate) and observed methane production is inadequate to account for...
Authors
F. Chapelle, P.B. McMahon
Streamflow, lake-flow patterns, rainfall, and quality of water and sediment in the vicinity of a hazardous-waste landfill near Pinewood, South Carolina, March 1987 through early January 1989 Streamflow, lake-flow patterns, rainfall, and quality of water and sediment in the vicinity of a hazardous-waste landfill near Pinewood, South Carolina, March 1987 through early January 1989
No abstract available.
Authors
R.A. Burt, P.B. McMahon, J. F. Robertson, D.D. Nagle
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
Reconnaissance hydrogeologic investigation of the Defense Waste Processing Facility and vicinity, Savannah River Plant, South Carolina Reconnaissance hydrogeologic investigation of the Defense Waste Processing Facility and vicinity, Savannah River Plant, South Carolina
The hydrogeologic framework of the area around the Savannah River Plant, South Carolina consists of 2 to 3 separate water bearing units. In the northern half of the study area, the Barnwell and underlying McBean aquifers are considered one aquifer owing to the absence of the tan clay-confining unit between them. In the southern half of the study area they are separated by the tan clay...
Authors
K.F. Dennehy, D.C. Prowell, P.B. McMahon
Water movement in the unsaturated zone at a low-level radioactive-waste burial site near Barnwell, South Carolina Water movement in the unsaturated zone at a low-level radioactive-waste burial site near Barnwell, South Carolina
Four unsaturated-zone monitoring sites and a meteorologic station were installed at the low-level radioactive-waste burial site near Barnwell, S.C., to investigate the geohydrologic and climatologic factors affecting water movement in the unsaturated zone. The study site is located in the Atlantic Coastal Plain. The unsaturated zone consists of a few centimeters to more than 1 meter of...
Authors
Kevin Dennehy, Peter McMahon
Science and Products
Filter Total Items: 14
No Result Found
Filter Total Items: 118
Microbial production of organic acids in aquitard sediments and its role in aquifer geochemistry Microbial production of organic acids in aquitard sediments and its role in aquifer geochemistry
Microbial activity in aquifers plays an important part in the chemical evolution of ground water1–5. The most important terminal electron-accepting microbial processes in deeply buried anaerobic aquifers are iron reduction, sulphate reduction and methanogenesis5–8, each of which requires simple organic compounds or hydrogen (H2) as electron donors. Until now, the source of these...
Authors
P.B. McMahon, F. Chapelle
Geochemistry of dissolved inorganic carbon in a Coastal Plain aquifer. 1. Sulfate from confining beds as an oxidant in microbial CO2 production Geochemistry of dissolved inorganic carbon in a Coastal Plain aquifer. 1. Sulfate from confining beds as an oxidant in microbial CO2 production
A primary source of dissolved inorganic carbon (DIC) in the Black Creek aquifer of South Carolina is carbon dioxide produced by microbially mediated oxidation of sedimentary organic matter. Groundwater chemistry data indicate, however, that the available mass of inorganic electron acceptors (oxygen, Fe(III), and sulfate) and observed methane production is inadequate to account for...
Authors
F. Chapelle, P.B. McMahon
Streamflow, lake-flow patterns, rainfall, and quality of water and sediment in the vicinity of a hazardous-waste landfill near Pinewood, South Carolina, March 1987 through early January 1989 Streamflow, lake-flow patterns, rainfall, and quality of water and sediment in the vicinity of a hazardous-waste landfill near Pinewood, South Carolina, March 1987 through early January 1989
No abstract available.
Authors
R.A. Burt, P.B. McMahon, J. F. Robertson, D.D. Nagle
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
Reconnaissance hydrogeologic investigation of the Defense Waste Processing Facility and vicinity, Savannah River Plant, South Carolina Reconnaissance hydrogeologic investigation of the Defense Waste Processing Facility and vicinity, Savannah River Plant, South Carolina
The hydrogeologic framework of the area around the Savannah River Plant, South Carolina consists of 2 to 3 separate water bearing units. In the northern half of the study area, the Barnwell and underlying McBean aquifers are considered one aquifer owing to the absence of the tan clay-confining unit between them. In the southern half of the study area they are separated by the tan clay...
Authors
K.F. Dennehy, D.C. Prowell, P.B. McMahon
Water movement in the unsaturated zone at a low-level radioactive-waste burial site near Barnwell, South Carolina Water movement in the unsaturated zone at a low-level radioactive-waste burial site near Barnwell, South Carolina
Four unsaturated-zone monitoring sites and a meteorologic station were installed at the low-level radioactive-waste burial site near Barnwell, S.C., to investigate the geohydrologic and climatologic factors affecting water movement in the unsaturated zone. The study site is located in the Atlantic Coastal Plain. The unsaturated zone consists of a few centimeters to more than 1 meter of...
Authors
Kevin Dennehy, Peter McMahon