Douglas Kent
Dr. Douglas Kent is a scientist emeritus with the Earth System Processes Division of the Water Mission Area, U. S. Geological Survey.
Doug Kent received an AA from Pasadena City College, a BA in chemistry from the University of California, San Diego and a PhD from Scripps Institution of Oceanography. He has conducted hydrologic research at the USGS since 1985.
Doug Kent's research at the USGS has focused on processes influencing the mobility of constituents that can affect the availability of water for beneficial use by humans and for sustaining aquatic ecosystems.
Science and Products
Filter Total Items: 15
Geochemistry Data from Samples Collected in 2015-2017 to study an OG wastewater spill in Blacktail Creek, North Dakota Geochemistry Data from Samples Collected in 2015-2017 to study an OG wastewater spill in Blacktail Creek, North Dakota
These metadata sets present the comprehensive geochemical composition of solid and water samples from the site of a 11.4ML (million liters) wastewater spill discovered in January, 2015. Analyses of a pipeline sample (analyses of select analytes), supplied by the North Dakota Department of Health are also included. The spill was near Blacktail Creek, north of Williston, ND. The leak was...
Seasonal and spatial variation in the location and reactivity of a nitrate-contaminated groundwater discharge zone in a lakebed Seasonal and spatial variation in the location and reactivity of a nitrate-contaminated groundwater discharge zone in a lakebed
The U.S. Geological Survey Toxic Substances Hydrology Program at Cape Cod has been investigating the fate and transport of a treated-wastewater, groundwater contaminant plume. A portion of the contaminated groundwater discharges into Ashumet Pond, a kettle hole, freshwater lake. A study was conducted from June 2013 to June 2015 to document transport, transformation, and discharge of...
Natural gradient, lakebed tracer tests using nitrite in a nitrate-contaminated groundwater discharge zone in Ashumet Pond, Massachusetts Natural gradient, lakebed tracer tests using nitrite in a nitrate-contaminated groundwater discharge zone in Ashumet Pond, Massachusetts
The U.S. Geological Survey Toxic Substances Hydrology Program at Cape Cod has been investigating the fate and transport of a treated-wastewater, groundwater contaminant plume. A portion of the contaminated groundwater discharges into Ashumet Pond, a kettle hole, freshwater lake. A study was conducted from June 2013 to June 2015 to document transport, transformation, and discharge of...
Filter Total Items: 53
Extent and persistence of secondary water quality impacts after enhanced reductive bioremediation Extent and persistence of secondary water quality impacts after enhanced reductive bioremediation
Electron donor (ED) addition can be very effective in stimulating enhanced reductive bioremediation (ERB) of a wide variety of groundwater contaminants. However, ERB can result in Secondary Water Quality Impacts (SWQIs) including decreased levels of dissolved oxygen (O2), nitrate (NO3- ), and sulfate (SO42- ), and elevated levels of dissolved manganese (Mn2+), dissolved iron (Fe2+)...
Authors
Robert C. Borden, Jason M. Tillotson, Gene-Hua Crystal Ng, Barbara A. Bekins, Douglas B. Kent, Gary P. Curtis
Environmental signatures and effects of an oil and gas wastewater spill in the Williston Basin, North Dakota Environmental signatures and effects of an oil and gas wastewater spill in the Williston Basin, North Dakota
Wastewaters from oil and gas development pose largely unknown risks to environmental resources. In January 2015, 11.4 M L (million liters) of wastewater (300 g/L TDS) from oil production in the Williston Basin was reported to have leaked from a pipeline, spilling into Blacktail Creek, North Dakota. Geochemical and biological samples were collected in February and June 2015 to identify...
Authors
Isabelle M. Cozzarelli, Katherine Skalak, D.B. Kent, Mark A. Engle, Adam J. Benthem, Adam C. Mumford, Karl B. Haase, Aida M. Farag, David Harper, S. C. Nagel, Luke R. Iwanowicz, William H. Orem, Denise M. Akob, Jeanne B. Jaeschke, Joel M. Galloway, Matthias Kohler, Deborah L. Stoliker, Glenn D. Jolly
Anoxic nitrate reduction coupled with iron oxidation and attenuation of dissolved arsenic and phosphate in a sand and gravel aquifer Anoxic nitrate reduction coupled with iron oxidation and attenuation of dissolved arsenic and phosphate in a sand and gravel aquifer
Nitrate has become an increasingly abundant potential electron acceptor for Fe(II) oxidation in groundwater, but this redox couple has not been well characterized within aquifer settings. To investigate this reaction and some of its implications for redox-sensitive groundwater contaminants, we conducted an in situ field study in a wastewater-contaminated aquifer on Cape Cod. Long-term...
Authors
Richard L. Smith, Douglas B. Kent, Deborah A. Repert, J. K. Böhlke
Wastewater disposal from unconventional oil and gas development degrades stream quality at a West Virginia injection facility Wastewater disposal from unconventional oil and gas development degrades stream quality at a West Virginia injection facility
The development of unconventional oil and gas (UOG) resources has rapidly increased in recent years; however, the environmental impacts and risks are poorly understood. A single well can generate millions of liters of wastewater, representing a mixture of formation brine and injected hydraulic fracturing fluids. One of the most common methods for wastewater disposal is underground...
Authors
Denise M. Akob, Adam C. Mumford, William H. Orem, Mark A. Engle, Julia Klinges, Douglas B. Kent, Isabelle M. Cozzarelli
Hydrologic controls on nitrogen cycling processes and functional gene abundance in sediments of a groundwater flow-through lake Hydrologic controls on nitrogen cycling processes and functional gene abundance in sediments of a groundwater flow-through lake
The fate and transport of inorganic nitrogen (N) is a critically important issue for human and aquatic ecosystem health because discharging N-contaminated groundwater can foul drinking water and cause algal blooms. Factors controlling N-processing were examined in sediments at three sites with contrasting hydrologic regimes at a lake on Cape Cod, MA. These factors included water...
Authors
Deborah L. Stoliker, Deborah A. Repert, Richard L. Smith, Bongkeun Song, Denis R. LeBlanc, Timothy D. McCobb, Christopher H. Conaway, Sung Pil Hyun, Dong-Chan Koh, Hee Sun Moon, Douglas B. Kent
Mercury speciation and mobilization in a wastewater-contaminated groundwater plume Mercury speciation and mobilization in a wastewater-contaminated groundwater plume
We measured the concentration and speciation of mercury (Hg) in groundwater down-gradient from the site of wastewater infiltration beds operated by the Massachusetts Military Reservation, western Cape Cod, Massachusetts. Total mercury concentrations in oxic, mildly acidic, uncontaminated groundwater are 0.5–1 pM, and aquifer sediments have 0.5–1 ppb mercury. The plume of impacted...
Authors
Carl H. Lamborg, Doug B. Kent, Gretchen J. Swarr, Kathleen M. Munson, Tristan Kading, Alison E. O’Connor, Gillian M. Fairchild, Denis R. LeBlanc, Heather A. Wiatrowski
Evaluating chemical extraction techniques for the determination of uranium oxidation state in reduced aquifer sediments Evaluating chemical extraction techniques for the determination of uranium oxidation state in reduced aquifer sediments
Extraction techniques utilizing high pH and (bi)carbonate concentrations were evaluated for their efficacy in determining the oxidation state of uranium (U) in reduced sediments collected from Rifle, CO. Differences in dissolved concentrations between oxic and anoxic extractions have been proposed as a means to quantify the U(VI) and U(IV) content of sediments. An additional step was...
Authors
Deborah L. Stoliker, Kate M. Campbell, Patricia M. Fox, David M. Singer, Nazila Kaviani, Minna Carey, Nicole E. Peck, John R. Barger, Douglas B. Kent, James A. Davis
Kinetics of homogeneous and surface-catalyzed mercury(II) reduction by iron(II) Kinetics of homogeneous and surface-catalyzed mercury(II) reduction by iron(II)
Production of elemental mercury, Hg(0), via Hg(II) reduction is an important pathway that should be considered when studying Hg fate in environment. We conducted a kinetic study of abiotic homogeneous and surface-catalyzed Hg(0) production by Fe(II) under dark anoxic conditions. Hg(0) production rate, from initial 50 pM Hg(II) concentration, increased with increasing pH (5.5–8.1) and...
Authors
Aria Amirbahman, Douglas B. Kent, Gary P. Curtis, Mark C. Marvin-DiPasquale
Characterizing particle-scale equilibrium adsorption and kinetics of uranium(VI) desorption from U-contaminated sediments Characterizing particle-scale equilibrium adsorption and kinetics of uranium(VI) desorption from U-contaminated sediments
Rates of U(VI) release from individual dry-sieved size fractions of a field-aggregated, field-contaminated composite sediment from the seasonally saturated lower vadose zone of the Hanford 300-Area were examined in flow-through reactors to maintain quasi-constant chemical conditions. The principal source of variability in equilibrium U(VI) adsorption properties of the various size...
Authors
Deborah L. Stoliker, Chongxuan Liu, Douglas B. Kent, John M. Zachara
Evaluating ion exchange resin efficiency and oxidative capacity for the separation of uranium(IV) and uranium(VI) Evaluating ion exchange resin efficiency and oxidative capacity for the separation of uranium(IV) and uranium(VI)
No abstract available.
Authors
Deborah L. Stoliker, Douglas B. Kent, Nazila Kaviani, James A. Davis
Groundwater-quality data for a treated-wastewater plume near the Massachusetts Military Reservation, Ashumet Valley, Cape Cod, Massachusetts, 2006-08 Groundwater-quality data for a treated-wastewater plume near the Massachusetts Military Reservation, Ashumet Valley, Cape Cod, Massachusetts, 2006-08
A plume of contaminated groundwater extends from former disposal beds at the Massachusetts Military Reservation's wastewater-treatment plant toward Ashumet Pond, coastal ponds, and Vineyard Sound, Cape Cod, Massachusetts. Treated sewage-derived wastewater was discharged to the rapid-infiltration beds for nearly 60 years before the disposal site was moved to a different location in...
Authors
Jennifer G. Savoie, Denis R. LeBlanc, Gillian M. Fairchild, Richard L. Smith, Douglas B. Kent, Larry B. Barber, Deborah A. Repert, Charles P. Hart, Steffanie H. Keefe, Luke A. Parsons
Mineralogy, morphology, and textural relationships in coatings on quartz grains in sediments in a quartz-sand aquifer Mineralogy, morphology, and textural relationships in coatings on quartz grains in sediments in a quartz-sand aquifer
Mineralogical studies of coatings on quartz grains and bulk sediments from an aquifer on Western Cape Cod, Massachusetts, USA were carried out using a variety of transmission electron microscopy (TEM) techniques. Previous studies demonstrated that coatings on quartz grains control the adsorption properties of these sediments. Samples for TEM characterization were made by a gentle...
Authors
Shouliang Zhang, Douglas B. Kent, David C. Elbert, Zhi Shi, James A. Davis, David R. Veblen
Non-USGS Publications**
Kent, D. B., and Kastner, M., 1985, Mg2+ removal in the system Mg2+‑amorphous SiO2‑H2O by adsorption and Mg‑hydroxysilicate precipitation: Geochimica et Cosmochimica Acta, v. 49, p. 1123‑1136.
Kent, D. B., 1983, On the surface chemical properties of synthetic and biogenic amorphous silica: Ph.D. dissertation, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California, 420 pp.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 15
Geochemistry Data from Samples Collected in 2015-2017 to study an OG wastewater spill in Blacktail Creek, North Dakota Geochemistry Data from Samples Collected in 2015-2017 to study an OG wastewater spill in Blacktail Creek, North Dakota
These metadata sets present the comprehensive geochemical composition of solid and water samples from the site of a 11.4ML (million liters) wastewater spill discovered in January, 2015. Analyses of a pipeline sample (analyses of select analytes), supplied by the North Dakota Department of Health are also included. The spill was near Blacktail Creek, north of Williston, ND. The leak was...
Seasonal and spatial variation in the location and reactivity of a nitrate-contaminated groundwater discharge zone in a lakebed Seasonal and spatial variation in the location and reactivity of a nitrate-contaminated groundwater discharge zone in a lakebed
The U.S. Geological Survey Toxic Substances Hydrology Program at Cape Cod has been investigating the fate and transport of a treated-wastewater, groundwater contaminant plume. A portion of the contaminated groundwater discharges into Ashumet Pond, a kettle hole, freshwater lake. A study was conducted from June 2013 to June 2015 to document transport, transformation, and discharge of...
Natural gradient, lakebed tracer tests using nitrite in a nitrate-contaminated groundwater discharge zone in Ashumet Pond, Massachusetts Natural gradient, lakebed tracer tests using nitrite in a nitrate-contaminated groundwater discharge zone in Ashumet Pond, Massachusetts
The U.S. Geological Survey Toxic Substances Hydrology Program at Cape Cod has been investigating the fate and transport of a treated-wastewater, groundwater contaminant plume. A portion of the contaminated groundwater discharges into Ashumet Pond, a kettle hole, freshwater lake. A study was conducted from June 2013 to June 2015 to document transport, transformation, and discharge of...
Filter Total Items: 53
Extent and persistence of secondary water quality impacts after enhanced reductive bioremediation Extent and persistence of secondary water quality impacts after enhanced reductive bioremediation
Electron donor (ED) addition can be very effective in stimulating enhanced reductive bioremediation (ERB) of a wide variety of groundwater contaminants. However, ERB can result in Secondary Water Quality Impacts (SWQIs) including decreased levels of dissolved oxygen (O2), nitrate (NO3- ), and sulfate (SO42- ), and elevated levels of dissolved manganese (Mn2+), dissolved iron (Fe2+)...
Authors
Robert C. Borden, Jason M. Tillotson, Gene-Hua Crystal Ng, Barbara A. Bekins, Douglas B. Kent, Gary P. Curtis
Environmental signatures and effects of an oil and gas wastewater spill in the Williston Basin, North Dakota Environmental signatures and effects of an oil and gas wastewater spill in the Williston Basin, North Dakota
Wastewaters from oil and gas development pose largely unknown risks to environmental resources. In January 2015, 11.4 M L (million liters) of wastewater (300 g/L TDS) from oil production in the Williston Basin was reported to have leaked from a pipeline, spilling into Blacktail Creek, North Dakota. Geochemical and biological samples were collected in February and June 2015 to identify...
Authors
Isabelle M. Cozzarelli, Katherine Skalak, D.B. Kent, Mark A. Engle, Adam J. Benthem, Adam C. Mumford, Karl B. Haase, Aida M. Farag, David Harper, S. C. Nagel, Luke R. Iwanowicz, William H. Orem, Denise M. Akob, Jeanne B. Jaeschke, Joel M. Galloway, Matthias Kohler, Deborah L. Stoliker, Glenn D. Jolly
Anoxic nitrate reduction coupled with iron oxidation and attenuation of dissolved arsenic and phosphate in a sand and gravel aquifer Anoxic nitrate reduction coupled with iron oxidation and attenuation of dissolved arsenic and phosphate in a sand and gravel aquifer
Nitrate has become an increasingly abundant potential electron acceptor for Fe(II) oxidation in groundwater, but this redox couple has not been well characterized within aquifer settings. To investigate this reaction and some of its implications for redox-sensitive groundwater contaminants, we conducted an in situ field study in a wastewater-contaminated aquifer on Cape Cod. Long-term...
Authors
Richard L. Smith, Douglas B. Kent, Deborah A. Repert, J. K. Böhlke
Wastewater disposal from unconventional oil and gas development degrades stream quality at a West Virginia injection facility Wastewater disposal from unconventional oil and gas development degrades stream quality at a West Virginia injection facility
The development of unconventional oil and gas (UOG) resources has rapidly increased in recent years; however, the environmental impacts and risks are poorly understood. A single well can generate millions of liters of wastewater, representing a mixture of formation brine and injected hydraulic fracturing fluids. One of the most common methods for wastewater disposal is underground...
Authors
Denise M. Akob, Adam C. Mumford, William H. Orem, Mark A. Engle, Julia Klinges, Douglas B. Kent, Isabelle M. Cozzarelli
Hydrologic controls on nitrogen cycling processes and functional gene abundance in sediments of a groundwater flow-through lake Hydrologic controls on nitrogen cycling processes and functional gene abundance in sediments of a groundwater flow-through lake
The fate and transport of inorganic nitrogen (N) is a critically important issue for human and aquatic ecosystem health because discharging N-contaminated groundwater can foul drinking water and cause algal blooms. Factors controlling N-processing were examined in sediments at three sites with contrasting hydrologic regimes at a lake on Cape Cod, MA. These factors included water...
Authors
Deborah L. Stoliker, Deborah A. Repert, Richard L. Smith, Bongkeun Song, Denis R. LeBlanc, Timothy D. McCobb, Christopher H. Conaway, Sung Pil Hyun, Dong-Chan Koh, Hee Sun Moon, Douglas B. Kent
Mercury speciation and mobilization in a wastewater-contaminated groundwater plume Mercury speciation and mobilization in a wastewater-contaminated groundwater plume
We measured the concentration and speciation of mercury (Hg) in groundwater down-gradient from the site of wastewater infiltration beds operated by the Massachusetts Military Reservation, western Cape Cod, Massachusetts. Total mercury concentrations in oxic, mildly acidic, uncontaminated groundwater are 0.5–1 pM, and aquifer sediments have 0.5–1 ppb mercury. The plume of impacted...
Authors
Carl H. Lamborg, Doug B. Kent, Gretchen J. Swarr, Kathleen M. Munson, Tristan Kading, Alison E. O’Connor, Gillian M. Fairchild, Denis R. LeBlanc, Heather A. Wiatrowski
Evaluating chemical extraction techniques for the determination of uranium oxidation state in reduced aquifer sediments Evaluating chemical extraction techniques for the determination of uranium oxidation state in reduced aquifer sediments
Extraction techniques utilizing high pH and (bi)carbonate concentrations were evaluated for their efficacy in determining the oxidation state of uranium (U) in reduced sediments collected from Rifle, CO. Differences in dissolved concentrations between oxic and anoxic extractions have been proposed as a means to quantify the U(VI) and U(IV) content of sediments. An additional step was...
Authors
Deborah L. Stoliker, Kate M. Campbell, Patricia M. Fox, David M. Singer, Nazila Kaviani, Minna Carey, Nicole E. Peck, John R. Barger, Douglas B. Kent, James A. Davis
Kinetics of homogeneous and surface-catalyzed mercury(II) reduction by iron(II) Kinetics of homogeneous and surface-catalyzed mercury(II) reduction by iron(II)
Production of elemental mercury, Hg(0), via Hg(II) reduction is an important pathway that should be considered when studying Hg fate in environment. We conducted a kinetic study of abiotic homogeneous and surface-catalyzed Hg(0) production by Fe(II) under dark anoxic conditions. Hg(0) production rate, from initial 50 pM Hg(II) concentration, increased with increasing pH (5.5–8.1) and...
Authors
Aria Amirbahman, Douglas B. Kent, Gary P. Curtis, Mark C. Marvin-DiPasquale
Characterizing particle-scale equilibrium adsorption and kinetics of uranium(VI) desorption from U-contaminated sediments Characterizing particle-scale equilibrium adsorption and kinetics of uranium(VI) desorption from U-contaminated sediments
Rates of U(VI) release from individual dry-sieved size fractions of a field-aggregated, field-contaminated composite sediment from the seasonally saturated lower vadose zone of the Hanford 300-Area were examined in flow-through reactors to maintain quasi-constant chemical conditions. The principal source of variability in equilibrium U(VI) adsorption properties of the various size...
Authors
Deborah L. Stoliker, Chongxuan Liu, Douglas B. Kent, John M. Zachara
Evaluating ion exchange resin efficiency and oxidative capacity for the separation of uranium(IV) and uranium(VI) Evaluating ion exchange resin efficiency and oxidative capacity for the separation of uranium(IV) and uranium(VI)
No abstract available.
Authors
Deborah L. Stoliker, Douglas B. Kent, Nazila Kaviani, James A. Davis
Groundwater-quality data for a treated-wastewater plume near the Massachusetts Military Reservation, Ashumet Valley, Cape Cod, Massachusetts, 2006-08 Groundwater-quality data for a treated-wastewater plume near the Massachusetts Military Reservation, Ashumet Valley, Cape Cod, Massachusetts, 2006-08
A plume of contaminated groundwater extends from former disposal beds at the Massachusetts Military Reservation's wastewater-treatment plant toward Ashumet Pond, coastal ponds, and Vineyard Sound, Cape Cod, Massachusetts. Treated sewage-derived wastewater was discharged to the rapid-infiltration beds for nearly 60 years before the disposal site was moved to a different location in...
Authors
Jennifer G. Savoie, Denis R. LeBlanc, Gillian M. Fairchild, Richard L. Smith, Douglas B. Kent, Larry B. Barber, Deborah A. Repert, Charles P. Hart, Steffanie H. Keefe, Luke A. Parsons
Mineralogy, morphology, and textural relationships in coatings on quartz grains in sediments in a quartz-sand aquifer Mineralogy, morphology, and textural relationships in coatings on quartz grains in sediments in a quartz-sand aquifer
Mineralogical studies of coatings on quartz grains and bulk sediments from an aquifer on Western Cape Cod, Massachusetts, USA were carried out using a variety of transmission electron microscopy (TEM) techniques. Previous studies demonstrated that coatings on quartz grains control the adsorption properties of these sediments. Samples for TEM characterization were made by a gentle...
Authors
Shouliang Zhang, Douglas B. Kent, David C. Elbert, Zhi Shi, James A. Davis, David R. Veblen
Non-USGS Publications**
Kent, D. B., and Kastner, M., 1985, Mg2+ removal in the system Mg2+‑amorphous SiO2‑H2O by adsorption and Mg‑hydroxysilicate precipitation: Geochimica et Cosmochimica Acta, v. 49, p. 1123‑1136.
Kent, D. B., 1983, On the surface chemical properties of synthetic and biogenic amorphous silica: Ph.D. dissertation, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California, 420 pp.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.