Sources of speciated atmospheric mercury at a residential neighborhood impacted by industrial sources
H. Manolopoulos, D.C. Snyder, James J Schauer, J.S. Hill, J.R. Turner, Mark L. Olson, David P. Krabbenhoft
2007, Environmental Science & Technology (41) 5626-5633
Speciated measurements of atmospheric mercury plumes were obtained at an industrially impacted residential area of East St. Louis, IL. These plumes were found to result in extremely high mercury concentrations at ground level that were composed of a wide distribution of mercury species. Ground level concentrations as high as 235...
Revisiting the cape cod bacteria injection experiment using a stochastic modeling approach
Reed M. Maxwell, Claire Welty, Ronald W. Harvey
2007, Environmental Science & Technology (41) 5548-5558
Bromide and resting-cell bacteria tracer tests conducted in a sandy aquifer at the U.S. Geological Survey Cape Cod site in 1987 were reinterpreted using a three-dimensional stochastic approach. Bacteria transport was coupled to colloid filtration theory through functional dependence of local-scale colloid transport parameters upon hydraulic conductivity and seepage velocity...
Water table fluctuations under three riparian land covers, Iowa (USA)
K. E. Schilling
2007, Hydrological Processes (21) 2415-2424
Water table depth is known to play an important role in nitrogen cycling in riparian zones, but little detailed monitoring of water table fluctuations has been reported. In this study, results of high-resolution water table monitoring under three common riparian land covers (forest, cool season grass, corn) were analysed to...
Distributed energy-balance modeling of snow-cover evolution and melt in rugged terrain: Tobacco Root Mountains, Montana, USA
S.L. Letsinger, G.A. Olyphant
2007, Journal of Hydrology (336) 48-60
A distributed energy-balance model was developed for simulating snowpack evolution and melt in rugged terrain. The model, which was applied to a 43-km2 watershed in the Tobacco Root Mountains, Montana, USA, used measured ambient data from nearby weather stations to drive energy-balance calculations and to constrain the model of Liston...
Climate variability controls on unsaturated water and chemical movement, High Plains aquifer, USA
J.J. Gurdak, R. T. Hanson, P.B. McMahon, B. W. Bruce, J.E. McCray, G.D. Thyne, R.C. Reedy
2007, Vadose Zone Journal (6) 533-547
Responses in the vadose zone and groundwater to interannual, interdecadal, and multidecadal climate variability have important implications for groundwater resource sustainability, yet they are poorly documented and not well understood in most aquifers of the USA. This investigation systematically examines the role of interannual to...
Distribution of selected halogenated organic compounds among suspended particulate, colloid, and aqueous phases in the Mississippi River and major tributaries
Colleen E. Rostad, S.R. Daniel
2007, Archives of Environmental Contamination and Toxicology (53) 151-158
Suspended particulate, colloid, and aqueous phases were separated and analyzed to determine spatial variation of specific organic compound transport associated with each phase in a dynamic river system. Sixteen sites along the Mississippi River and its major tributaries were sampled at low-flow conditions to maximize the possibility of equilibrium. Across...
A method to estimate groundwater depletion from confining layers
Leonard F. Konikow, Christopher E. Neuzil
2007, Water Resources Research (43)
Although depletion of storage in low‐permeability confining layers is the source of much of the groundwater produced from many confined aquifer systems, it is all too frequently overlooked or ignored. This makes effective management of groundwater resources difficult by masking how much water has been derived from storage and, in...
Holocene sea level and climate change in the Black Sea: Multiple marine incursions related to freshwater discharge events
R.E. Martin, E. Leorri, P.P. McLaughlin
2007, Quaternary International (167-168) 61-72
Repeated marine invasions of the Black Sea during the Holocene have been inferred by many eastern scientists as resulting from episodes of marine inflow from the Mediterranean beneath a brackish outflow from the Black Sea. We support this scenario but a fundamental question remains: What caused the repeated marine invasions?...
Estimating the bankfull velocity and discharge for rivers using remotely sensed river morphology information
D.M. Bjerklie
2007, Journal of Hydrology (341) 144-155
A method to estimate the bankfull velocity and discharge in rivers that uses the morphological variables of the river channel, including bankfull width, channel slope, and meander length was developed and tested. Because these variables can be measured remotely from topographic and river alignment information derived from aerial photos and...
Identifying sources of nitrogen to Hanalei Bay, Kauai, utilizing the nitrogen isotope signature of macroalgae
E. Derse, K.L. Knee, Scott D. Wankel, Carol Kendall, Carl J. Berg Jr., A. Paytan
2007, Environmental Science & Technology (41) 5217-5223
Sewage effluent, storm runoff, discharge from polluted rivers, and inputs of groundwater have all been suggested as potential sources of land derived nutrients into Hanalei Bay, Kauai. We determined the nitrogen isotopic signatures (δ15N) of different nitrate sources to Hanalei Bay...
Deglacial climate variability in central Florida, USA
Debra A. Willard, C.E. Bernhardt, G. R. Brooks, T. M. Cronin, T. Edgar, R. Larson
2007, Palaeogeography, Palaeoclimatology, Palaeoecology (251) 366-382
Pollen and ostracode evidence from lacustrine sediments underlying modern Tampa Bay, Florida, document frequent and abrupt climatic and hydrological events superimposed on deglacial warming in the subtropics. Radiocarbon chronology on well-preserved mollusk shells and pollen residue from core MD02-2579 documents continuous sedimentation in a variety of non-marine habitats in a...
Monitoring engineered remediation with borehole radar
John W. Lane Jr., Frederick D. Day-Lewis, Peter K. Joesten
2007, The Leading Edge (26) 1032-1035
The success of engineered remediation is predicated on correct emplacement of either amendments (e.g., vegetable-oil emulsion, lactate, molasses, etc.) or permeable reactive barriers (e.g., vegetable oil, zero-valent iron, etc.) to enhance microbial or geochemical breakdown of contaminants and treat contaminants. Currently, site managers have limited tools to provide information about...
Thioarsenates in geothermal waters of Yellowstone National Park: Determination, preservation, and geochemical importance
B. Planer-Friedrich, J. London, R. Blaine McCleskey, D. Kirk Nordstrom, D. Wallschlager
2007, Environmental Science & Technology (41) 5245-5251
Mono-, di-, tri-, and tetrathioarsenate, as well as methylated arsenic oxy- and thioanions, were determined besides arsenite and arsenate in geothermal waters of Yellowstone National Park using anion-exchange chromatography inductively coupled plasma mass spectrometry. Retention time match with synthetic standards, measured S:As ratios, and molecular electrospray mass spectra support the...
Oxygen isotopes in nitrite: Analysis, calibration, and equilibration
K.L. Casciotti, John Karl Bohlke, M.R. McIlvin, Stanley J. Mroczkowski, Janet E. Hannon
2007, Analytical Chemistry (79) 2427-2436
Nitrite is a central intermediate in the nitrogen cycle and can persist in significant concentrations in ocean waters, sediment pore waters, and terrestrial groundwaters. To fully interpret the effect of microbial processes on nitrate (NO3-), nitrite (NO2-), and nitrous oxide (N2O) cycling in these systems, the nitrite pool must be...
Water use regimes: Characterizing direct human interaction with hydrologic systems
Peter K. Weiskel, Richard M. Vogel, Peter A. Steeves, Philip J. Zarriello, Leslie A. DeSimone, Kernell G. Ries III
2007, Water Resources Research (43)
The sustainability of human water use practices is a rapidly growing concern in the United States and around the world. To better characterize direct human interaction with hydrologic systems (stream basins and aquifers), we introduce the concept of the water use regime. Unlike scalar indicators of anthropogenic hydrologic stress in...
Isotopic analysis of N and O in nitrite and nitrate by sequential selective bacterial reduction to N2O
John Karl Bohlke, Richard L. Smith, Janet E. Hannon
2007, Analytical Chemistry (79) 5888-5895
Nitrite is an important intermediate species in the biogeochemical cycling of nitrogen, but its role in natural aquatic systems is poorly understood. Isotopic data can be used to study the sources and transformations of NO2- in the environment, but methods for independent isotopic analyses of NO2- in the presence of...
Ecohydrological controls on soil moisture and hydraulic conductivity within a pinyon‐juniper woodland
I. Lebron, M.D. Madsen, D.G. Chandler, D.A. Robinson, O. Wendroth, J. Belnap
2007, Water Resources Research (43)
The impact of pinyon‐juniper woodland encroachment on rangeland ecosystems is often associated with a reduction of streamflow and recharge and an increase in soil erosion. The objective of this study is to investigate vegetational control on seasonal soil hydrologic properties along a 15‐m transect in pinyon‐juniper woodland with biocrust. We...
Spatial and temporal variations in silver contamination and toxicity in San Francisco Bay
A.R. Flegal, Cynthia L. Brown, S. Squire, J.R.M. Ross, G.M. Scelfo, S. Hibdon
2007, Environmental Research (105) 34-52
Although San Francisco Bay has a "Golden Gate", it may be argued that it is the "Silver Estuary". For at one time the Bay was reported to have the highest levels of silver in its sediments and biota, along with the only accurately measured values of silver in solution, of...
Nitrification in the euphotic zone as evidenced by nitrate dual isotopic composition: Observations from Monterey Bay, California
Scott D. Wankel, Carol Kendall, J.T. Pennington, Francisco P. Chavez, Adina Paytan
2007, Global Biogeochemical Cycles (21)
Coupled measurements of nitrate (NO3−), nitrogen (N), and oxygen (O) isotopic composition (δ15NNO3 and δ18ONO3) were made in surface waters of Monterey Bay to investigate multiple N cycling processes occurring within surface waters. Profiles collected throughout the year at three sites exhibit a wide range of values, suggesting simultaneous...
Recent climate trends and implications for water resources in the Catskill Mountain region, New York, USA
Douglas A. Burns, Julian Klaus, Michael R. McHale
2007, Journal of Hydrology (336) 155-170
Climate scientists have concluded that the earth’s surface air temperature warmed by 0.6 °C during the 20th century, and that warming induced by increasing concentrations of greenhouse gases is likely to continue in the 21st century, accompanied by changes in the hydrologic cycle. Climate change has important implications in the Catskill...
Isotopic characterization of three groundwater recharge sources and inferences for selected aquifers in the upper Klamath Basin of Oregon and California, USA
P.C. Palmer, M. W. Gannett, S.R. Hinkle
2007, Journal of Hydrology (336) 17-29
Stable isotope (??D and ??18O) signatures of three principal groundwater recharge areas in the 21,000-km2 upper Klamath Basin are used to infer recharge sources for aquifers in the interior parts of the basin. Two of the principal recharge areas, the Cascade Range on the western and southern margin of the...
Evidence for terrigenic SF6 in groundwater from basaltic aquifers, Jeju Island, Korea: Implications for groundwater dating
Dong-Chan Koh, Niel Plummer, Eurybiades Busenberg, Yongje Kim
2007, Journal of Hydrology (339) 93-104
Measurements of the concentrations of dichlorodifluoromethane (CFC-12), tritium (3H), and sulfur hexafluoride (SF6) in groundwater from basaltic aquifers in Jeju Island, Korea, demonstrate a terrigenic source of SF6. Using a lumped-parameter dispersion model, groundwater was identified as young water (<15 years), old water with negligible CFC-12 and 3H, and binary mixtures...
Nitrate dynamics within the Pajaro River, a nutrient-rich, losing stream
C.R. Ruehl, A.T. Fisher, Huertos M. Los, Scott D. Wankel, C.G. Wheat, Carol Kendall, C.E. Hatch, C. Shennan
2007, Journal of the North American Benthological Society (26) 191-206
The major ion chemistry of water from an 11.42-km reach of the Pajaro River, a losing stream in central coastal California, shows a consistent pattern of higher concentrations during the 2nd (dry) half of the water year. Most solutes are conserved during flow along the reach, but [NO3−] decreases by...
Correcting acoustic Doppler current profiler discharge measurement bias from moving-bed conditions without global positioning during the 2004 Glen Canyon Dam controlled flood on the Colorado River
J. W. Gartner, N. K. Ganju
2007, Limnology and Oceanography: Methods (5) 156-162
Discharge measurements were made by acoustic Doppler current profiler at two locations on the Colorado River during the 2004 controlled flood from Glen Canyon Dam, Arizona. Measurement hardware and software have constantly improved from the 1980s such that discharge measurements by acoustic profiling instruments are now routinely made over a...
Flux and age of dissolved organic carbon exported to the Arctic Ocean: A carbon isotopic study of the five largest arctic rivers
P.A. Raymond, J.W. McClelland, R.M. Holmes, A.V. Zhulidov, K. Mull, B. J. Peterson, Robert G. Striegl, G. R. Aiken, T.Y. Gurtovaya
2007, Global Biogeochemical Cycles (21)
The export and Δ14C-age of dissolved organic carbon (DOC) was determined for the Yenisey, Lena, Ob', Mackenzie, and Yukon rivers for 2004–2005. Concentrations of DOC elevate significantly with increasing discharge in these rivers, causing approximately 60% of the annual export to occur during a 2-month period following spring ice breakup....
