Todd Hoefen
Todd Hoefen is a Geophysicist with the Geology, Geophysics, and Geochemistry Science Center.
Science and Products
Filter Total Items: 110
Simultaneous speciation of arsenic, selenium, and chromium: species, stability, sample preservation, and analysis of ash and soil leachates Simultaneous speciation of arsenic, selenium, and chromium: species, stability, sample preservation, and analysis of ash and soil leachates
An analytical method using high-performance liquid chromatography separation with inductively coupled plasma mass spectrometry (ICP-MS) detection previously developed for the determination of Cr(III) and Cr(VI) has been adapted to allow the determination of As(III), As(V), Se(IV), Se(VI), Cr(III), and Cr(VI) under the same chromatographic conditions. Using this method, all six inorganic...
Authors
Ruth E. Wolf, Suzette A. Morman, Philip L. Hageman, Todd M. Hoefen, Geoffrey S. Plumlee
Shoreline surveys of oil-impacted marsh in southern Louisiana, July to August 2010 Shoreline surveys of oil-impacted marsh in southern Louisiana, July to August 2010
This report describes shoreline surveys conducted in the marshes of Louisiana in areas impacted by oil spilled from the Deepwater Horizon offshore oil drilling platform in the Gulf of Mexico. Three field expeditions were conducted on July 7-10, August 12-14, and August 24-26, 2010, in central Barataria Bay and the Bird's Foot area at the terminus of the Mississippi River delta. This...
Authors
Raymond F. Kokaly, David Heckman, JoAnn Holloway, Sarai C. Piazza, Brady R. Couvillion, Gregory D. Steyer, Christopher T. Mills, Todd M. Hoefen
Simultaneous speciation of arsenic, selenium, and chromium: Species stability, sample preservation, and analysis of ash and soil leachates Simultaneous speciation of arsenic, selenium, and chromium: Species stability, sample preservation, and analysis of ash and soil leachates
An analytical method using high-performance liquid chromatography separation with inductively coupled plasma mass spectrometry (ICP-MS) detection previously developed for the determination of Cr(III) and Cr(VI) has been adapted to allow the determination of As(III), As(V), Se(IV), Se(VI), Cr(III), and Cr(VI) under the same chromatographic conditions. Using this method, all six inorganic...
Authors
R.E. Wolf, S.A. Morman, P. L. Hageman, T.M. Hoefen, G.S. Plumlee
Mapping the distribution of materials in hyperspectral data using the USGS Material Identification and Characterization Algorithm (MICA) Mapping the distribution of materials in hyperspectral data using the USGS Material Identification and Characterization Algorithm (MICA)
Identifying materials by measuring and analyzing their reflectance spectra has been an important method in analytical chemistry for decades. Airborne and space-based imaging spectrometers allow scientists to detect materials and map their distributions across the landscape. With new satellite-borne hyperspectral sensors planned for the future, for example, HYSPIRI (HYPerspectral InfraRed...
Authors
Raymond F. Kokaly, T. V. V. King, Todd M. Hoefen
The dispersion of fibrous amphiboles by glacial processes in the area surrounding Libby, Montana, USA The dispersion of fibrous amphiboles by glacial processes in the area surrounding Libby, Montana, USA
Mining operations began at a world-class vermiculite deposit at Vermiculite Mountain near Libby, Montana, circa 1920 and ended in 1990. Fibrous and asbestiform amphiboles intergrown with vermiculite ore are suspected to be a causative factor in an abnormally high number of cases of respiratory diseases in former mine and mill workers, and in residents of Libby. The question addressed in...
Authors
William H. Langer, Bradley S. Van Gosen, Gregory P. Meeker, David T. Adams, Todd M. Hoefen
Speciation of arsenic, selenium, and chromium in wildfire impacted soils and ashes Speciation of arsenic, selenium, and chromium in wildfire impacted soils and ashes
In 2007-09, California experienced several large wildfires that damaged large areas of forest and destroyed many homes and buildings. The U.S. Geological Survey collected samples from the Harris, Witch, Grass Valley, Ammo, Santiago, Canyon, Jesusita, and Station fires for testing to identify any possible characteristics of the ashes and soils from burned areas that may be of concern for...
Authors
Ruth E. Wolf, Todd M. Hoefen, Philip L. Hageman, Suzette A. Morman, Geoffrey S. Plumlee
Science and Products
Filter Total Items: 110
Simultaneous speciation of arsenic, selenium, and chromium: species, stability, sample preservation, and analysis of ash and soil leachates Simultaneous speciation of arsenic, selenium, and chromium: species, stability, sample preservation, and analysis of ash and soil leachates
An analytical method using high-performance liquid chromatography separation with inductively coupled plasma mass spectrometry (ICP-MS) detection previously developed for the determination of Cr(III) and Cr(VI) has been adapted to allow the determination of As(III), As(V), Se(IV), Se(VI), Cr(III), and Cr(VI) under the same chromatographic conditions. Using this method, all six inorganic...
Authors
Ruth E. Wolf, Suzette A. Morman, Philip L. Hageman, Todd M. Hoefen, Geoffrey S. Plumlee
Shoreline surveys of oil-impacted marsh in southern Louisiana, July to August 2010 Shoreline surveys of oil-impacted marsh in southern Louisiana, July to August 2010
This report describes shoreline surveys conducted in the marshes of Louisiana in areas impacted by oil spilled from the Deepwater Horizon offshore oil drilling platform in the Gulf of Mexico. Three field expeditions were conducted on July 7-10, August 12-14, and August 24-26, 2010, in central Barataria Bay and the Bird's Foot area at the terminus of the Mississippi River delta. This...
Authors
Raymond F. Kokaly, David Heckman, JoAnn Holloway, Sarai C. Piazza, Brady R. Couvillion, Gregory D. Steyer, Christopher T. Mills, Todd M. Hoefen
Simultaneous speciation of arsenic, selenium, and chromium: Species stability, sample preservation, and analysis of ash and soil leachates Simultaneous speciation of arsenic, selenium, and chromium: Species stability, sample preservation, and analysis of ash and soil leachates
An analytical method using high-performance liquid chromatography separation with inductively coupled plasma mass spectrometry (ICP-MS) detection previously developed for the determination of Cr(III) and Cr(VI) has been adapted to allow the determination of As(III), As(V), Se(IV), Se(VI), Cr(III), and Cr(VI) under the same chromatographic conditions. Using this method, all six inorganic...
Authors
R.E. Wolf, S.A. Morman, P. L. Hageman, T.M. Hoefen, G.S. Plumlee
Mapping the distribution of materials in hyperspectral data using the USGS Material Identification and Characterization Algorithm (MICA) Mapping the distribution of materials in hyperspectral data using the USGS Material Identification and Characterization Algorithm (MICA)
Identifying materials by measuring and analyzing their reflectance spectra has been an important method in analytical chemistry for decades. Airborne and space-based imaging spectrometers allow scientists to detect materials and map their distributions across the landscape. With new satellite-borne hyperspectral sensors planned for the future, for example, HYSPIRI (HYPerspectral InfraRed...
Authors
Raymond F. Kokaly, T. V. V. King, Todd M. Hoefen
The dispersion of fibrous amphiboles by glacial processes in the area surrounding Libby, Montana, USA The dispersion of fibrous amphiboles by glacial processes in the area surrounding Libby, Montana, USA
Mining operations began at a world-class vermiculite deposit at Vermiculite Mountain near Libby, Montana, circa 1920 and ended in 1990. Fibrous and asbestiform amphiboles intergrown with vermiculite ore are suspected to be a causative factor in an abnormally high number of cases of respiratory diseases in former mine and mill workers, and in residents of Libby. The question addressed in...
Authors
William H. Langer, Bradley S. Van Gosen, Gregory P. Meeker, David T. Adams, Todd M. Hoefen
Speciation of arsenic, selenium, and chromium in wildfire impacted soils and ashes Speciation of arsenic, selenium, and chromium in wildfire impacted soils and ashes
In 2007-09, California experienced several large wildfires that damaged large areas of forest and destroyed many homes and buildings. The U.S. Geological Survey collected samples from the Harris, Witch, Grass Valley, Ammo, Santiago, Canyon, Jesusita, and Station fires for testing to identify any possible characteristics of the ashes and soils from burned areas that may be of concern for...
Authors
Ruth E. Wolf, Todd M. Hoefen, Philip L. Hageman, Suzette A. Morman, Geoffrey S. Plumlee