Staff Members at RSIL

12201 Sunrise Valley Drive, Mail Stop 431,  Reston, VA 20192
Fax: (703) 648-5832     Phone: (703) 648-5859
E-mail: isotopes@usgs.gov

J.K. Bohlke – (Research Hydrologist: jkbohlke@usgs.gov, 703-648-6325) is interested generally in the sources and fates of fluids and dissolved constituents in the Earth's crust, mass transfers and buffering mechanisms during fluid-rock interactions, stable and radioactive isotope geochemistry, and geochronology. Recent studies have focused on the transfer of various non-point-source pollutants through watersheds, with emphasis on the history and fate of nitrate in ground water.

Bryan Buck– (Engineering Technician: 703-648-5874) provides indispensable mechanical support and development, as well as preparing and analyzing samples for isotopic composition.

Tyler B. Coplen – (Research Chemist: tbcoplen@usgs.gov, 703-648-5862) uses variations in the isotopic abundances of hydrogen, carbon, nitrogen, oxygen, and sulfur to investigate problems in hydrology, geochemistry, and paleoclimatology, oversees the analysis of samples submitted by District personnel to the National Water Quality Laboratory for isotopic analysis, and develops new sample preparation and mass spectrometric data acquisition and control techniques for analysis of the isotopes of light elements.

Sara Coplen Glidewell – (Web Developer)

Janet Hannon – (Chemist: jehannon@usgs.gov, 703-648-5202) analyzes water samples and solids for nitrogen-15 of nitrate, ammonia, and organic nitrogen. Develops ion exchange methods for separating ammonia, nitrite, nitrate, chloride, and sulfate.

James Jordan – (Visiting Scientist: jajordan@usgs.gov, 703-648-5836) is highly experienced in analytical chemistry and is interested in development of new methods for of hydrogen, carbon, nitrogen, oxygen, and sulfur isotope ratio determinations in organic materials

Jennifer Lorenz – (Biological Science Technician: jlorenz@usgs.gov, 703-648-5859) prepares and analyzes water and other samples for hydrogen, carbon, nitrogen, oxygen, and sulfur isotope ratio analysis.

Stanley Mroczkowski – (Chemist: smroczko@usgs.gov, 703-648-5870) performs delta nitrogen-15 analysis of nitrate, ammonia, and dissolved gaseous nitrogen. Performs delta oxygen-18 analysis of nitrate and sulfate.

Nancy Padilla – (Project Assistant: npadilla@usgs.gov, 703-648-5854) provides indispensable administrative support.

Katharine Pecsok – (Hydrologist: kpecsok@usgs.gov, 703-648-5950) is a National Association of Geosciences Teachers (NAGT) scholar and is assisting in the project titled “Developing Hydrogen and Oxygen Isoscapes of U.S. Tap Waters with Application to Hydrology, Ecology and Forensic Discrimination.”

Haiping Qi – (Chemist: haipingq@usgs.gov, 703-648-6338) is experienced in solid-source mass spectrometry (e.g., Li, B, and Cl isotopes) and gas source mass spectrometry techniques as well. She is involved in preparation of new isotopic reference materials, and assists in laboratory management and daily operation of the laboratory, analyzing samples submitted for hydrogen, carbon, nitrogen, oxygen, and sulfur isotope ratio determination.

Kinga M. Revesz – (Research Chemist: krevesz@usgs.gov, 703-648-5865) is concerned broadly with the use of stable isotopes, primarily hydrogen, carbon and oxygen, to examine the dynamics of hydrological systems and associated geochemical problems. Performs studies in the identification and quantification of ground-water recharge, discharge, and surface-water/ground-water interaction, as well as redox processes in contaminated aquifers. Develops new sample preparation techniques in the laboratory including inlet systems for continuous flow isotope ratio analytical techniques , such as EA, TC/EA, GPI, Gasbench, GCC, and TC/GCC.

Glenda Singleton – (Physical Scientist: gsingleton@usgs.gov, 703-648-5864) prepares and analyzes water and other samples for hydrogen, carbon, nitrogen, oxygen, and sulfur isotope ratio analysis.