Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Filter Total Items: 3746
Improved online δ18O measurements of nitrogen‐ and sulfur‐bearing organic materials and a proposed analytical protocol
It is well known that N2 in the ion source of a mass spectrometer interferes with the CO background during the δ18O measurement of carbon monoxide. A similar problem arises with the high‐temperature conversion (HTC) analysis of nitrogenous O‐bearing samples (e.g. nitrates and keratins) to CO for δ18O measurement, where the sample introduces a significant N2 peak before the CO peak, making determin
Authors
Haiping Qi, Tyler B. Coplen, Leonard I Wassenaar
Lagrangian sampling of wastewater treatment plant effluent in Boulder Creek, Colorado, and Fourmile Creek, Iowa, during the summer of 2003 and spring of 2005— Hydrological and water-quality data
This report presents methods and data for a Lagrangian sampling investigation into chemical loading and in-stream attenuation of inorganic and organic contaminants in two wastewater treatment-plant effluent-dominated streams: Boulder Creek, Colorado, and Fourmile Creek, Iowa. Water-quality sampling was timed to coincide with low-flow conditions when dilution of the wastewater treatment-plant efflu
Authors
Larry B. Barber, Steffanie H. Keefe, Dana W. Kolpin, Douglas J. Schnoebelen, Jennifer L. Flynn, Gregory K. Brown, Edward T. Furlong, Susan T. Glassmeyer, James L. Gray, Michael T. Meyer, Mark W. Sandstrom, Howard E. Taylor, Steven D. Zaugg
Investigation of preparation techniques for δ2H analysis of keratin materials and a proposed analytical protocol
Accurate hydrogen isotopic measurements of keratin materials have been a challenge due to exchangeable hydrogen in the sample matrix and the paucity of appropriate isotopic reference materials for calibration. We found that the most reproducible δ2HVSMOW‐SLAP and mole fraction of exchangeable hydrogen, x(H)ex, of keratin materials were measured with equilibration at ambient temperature using two d
Authors
Haiping Qi, Tyler B. Coplen
IUPAC Periodic Table of the Isotopes
For almost 150 years, the Periodic Table of the Elements has served as a guide to the world of elements by highlighting similarities and differences in atomic structure and chemical properties. To introduce students, teachers, and society to the existence and importance of isotopes of the chemical elements, an IUPAC Periodic Table of the Isotopes (IPTI) has been prepared and can be found as a supp
Authors
N.E. Holden, T. B. Coplen, J.K. Böhlke, M.E. Wieser, G. Singleton, T. Walczyk, S. Yoneda, P.G. Mahaffy, L.V. Tarbox
Application of MODFLOW for oil reservoir simulation during the Deepwater Horizon Crisis
When the Macondo well was shut in on July 15, 2010, the shut-in pressure recovered to a level that indicated the possibility of oil leakage out of the well casing into the surrounding formation. Such a leak could initiate a hydraulic fracture that might eventually breach the seafloor, resulting in renewed and uncontrolled oil flow into the Gulf of Mexico. To help evaluate whether or not to reopen
Authors
Paul A. Hsieh
Grazing impact of the invasive clam Corbula amurensis on the microplankton assemblage of the northern San Francisco Estuary
Grazing by the overbite clam Corbula amurensis (formerly known as Potamocorbula) may be the cause of substantial declines in phytoplankton biomass and zooplankton in the San Francisco Estuary (SFE) following its introduction in 1986. While grazing rates have been examined on bacteria, phytoplankton, and copepod nauplii, the consumption of protistan microzooplankton by C. amurensis has not previous
Authors
Valerie E. Greene, Lindsay J. Sullivan, Janet K. Thompson, Wim J. Kimmerer
Diel biogeochemical processes in terrestrial waters
Many biogeochemical processes in rivers and lakes respond to the solar photocycle and produce persistent patterns of measureable phenomena that exhibit a day–night, or 24-h, cycle. Despite a large body of recent literature, the mechanisms responsible for these diel fluctuations are widely debated, with a growing consensus that combinations of physical, chemical, and biological processes are involv
Authors
David A. Nimick, Christopher H. Gammons
The aquatic real-time monitoring network; in-situ optical sensors for monitoring the nation's water quality
Floods, hurricanes, and longer-term changes in climate and land use can have profound effects on water quality due to shifts in hydrologic flow paths, water residence time, precipitation patterns, connectivity between rivers and uplands, and many other factors. In order to understand and respond to changes in hydrology and water quality, resource managers and policy makers have a need for accurate
Authors
Brian A. Pellerin, Brian A. Bergamaschi, Peter S. Murdoch, Bryan D. Downing, John Franco Saraceno, George R. Aiken, Robert G. Striegl
Stable-isotope ratios of hydrogen and oxygen in precipitation at Norman, Oklahoma, 1996–2008
Precipitation samples for measurement of stable-isotope ratios of hydrogen (delta2H) and oxygen (delta18O) were collected at the Norman Landfill Research Site in Norman, Oklahoma, from May 1996 to October 2008. Rainfall amounts also were measured at the site (U.S. Geological Survey gaging station 07229053) during the collection period. The delta2H of precipitation samples ranged from -121.9 to +8.
Authors
Jeanne B. Jaeschke, Martha A. Scholl, Isabelle M. Cozzarelli, Jason R. Masoner, Scott Christenson, Haiping Qi
Isotopic tracing of perchlorate in the environment
Isotopic measurements can be used for tracing the sources and behavior of environmental contaminants. Perchlorate (ClO 4 − ) has been detected widely in groundwater, soils, fertilizers, plants, milk, and human urine since 1997, when improved analytical methods for analyzing ClO 4 −concentration became available for routine use. Perchlorate ingestion poses a risk to human health because of its inte
Authors
Neil C. Sturchio, John K. Böhlke, Baohua Gu, Paul B. Hatzinger, W. Andrew Jackson
Seasonal dynamics of CO2 profiles across a soil chronosequence, Santa Cruz, California
Concentrations of CO2 in soil atmosphere and CO2 efflux were measured across a marine terrace soil chronosequence near Santa Cruz, California. Soil development, specifically the formation of an argillic horizon, has created a two-tier soil gas profile in the older terrace soils. The soil above the argillic horizon has seasonal variations in soil CO2 associated with plant respiration. The older soi
Authors
Marjorie S. Schulz, David A. Stonestrom, Guntram von Kiparski, Corey R. Lawrence, C.A. Masiello, Arthur F. White, John Fitzpatrick
Suspended sediment and organic contaminants in the San Lorenzo River, California, water years 2009-2010
This report presents analyses of suspended sediment and organic contaminants measured during a two-year study of the San Lorenzo River, central California, which discharges into the Pacific Ocean within the Monterey Bay National Marine Sanctuary. Most suspended-sediment transport occurred during flooding caused by winter storms; 55 percent of the sediment load was transported by the river during a
Authors
Amy E. Draut, Christopher H. Conaway, Kathy R. Echols, Curt D. Storlazzi, Andrew Ritchie