Dirt: The Erosion of Civilizations. David R. Montgomery, 2007, University of California Press,Berkeley, CA, 295 pp., $24.95 (hardcover)     

W. Cullen Sherwood 《Geoarchaeology》2008,23(3):420-422

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Is Our Ground Water Monitoring Strategy Illogical?     

Stephen J. Cullen  John H. Kramer  Lome G. Everett  Lawrence A. Eccles 《Ground Water Monitoring & Remediation》1992,12(3):103-107

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Vadose Zone Monitoring with the Neutron Moisture Probe     

John H. Kramer  Stephen J. Cullen  Lome G. Everett 《Ground Water Monitoring & Remediation》1992,12(3):177-187

The neutron moisture probe is widely applicable to vadose zone monitoring problems which require measuring variable moisture contents. Neutron data are proportional to hydrogen density (modified by local chemistry) and sensitive to wetting fronts as well as changing volumes of hydrocarbon liquids. They cannot, however, be used to confirm contaminant chemistry, nor to detect steady-state flow. Neutron data are amenable to statistical analysis, providing a measure of the significance of data variations. Detection of incipient moisture changes at numerous monitoring locations is more practical using raw neutron data than data calibrated for moisture content because calibrations suffer from uncertainties associated with soil heterogeneities. When properly applied, the neutron probe is an effective monitoring tool as illustrated by three example applications described in this paper: (1) neutron moisture logs are used to detect subtle lithologic changes and identify monitoring horizons; (2) sequential neutron data are used to track induced saturation at a soil flushing pilot study; and (3) neutron logs from a horizontal access tube beneath a waste facility are used to pinpoint moisture anomalies.  相似文献   

Early oxidation of organic matter in pelagic sediments of the eastern equatorial Atlantic: suboxic diagenesis   总被引：2，自引：0，他引：2  

P.N. Froelich  G.P. Klinkhammer  M.L. Bender  N.A. Luedtke  G.R. Heath  Doug Cullen  Paul Dauphin  Doug Hammond  Blayne Hartman  Val Maynard 《Geochimica et cosmochimica acta》1979,43(7):1075-1090

Pore water profiles of total-CO₂, pH, PO^3?₄, NO^?₃ plus NO^?₂, SO^2?₄, S^2?, Fe²⁺ and Mn²⁺ have been obtained in cores from pelagic sediments of the eastern equatorial Atlantic under waters of moderate to high productivity. These profiles reveal that oxidants are consumed in order of decreasing energy production per mole of organic carbon oxidized (O₂ > manganese oxides ~ nitrate > iron oxides > sulfate). Total CO₂ concentrations reflect organic regeneration and calcite dissolution. Phosphate profiles are consistent with organic regeneration and with the effects of release and uptake during inorganic reactions. Nitrate profiles reflect organic regeneration and nitrate reduction, while dissolved iron and manganese profiles suggest reduction of the solid oxide phases, upward fluxes of dissolved metals and subsequent entrapment in the sediment column. Sulfate values are constant and sulfide is absent, reflecting the absence of strongly anoxic conditions.  相似文献   

RIVER-WATER POLLUTION IN NORWAY: SOME REGIONAL ENVIRONMENTAL POLICY IMPLICATIONS*     

Lawrence M. Sommers  Bradley T. Cullen 《The Professional geographer》1982,34(2):208-219

This paper presents a systematic method of classifying water quality and identifies factors influencing the water quality of Norwegian rivers. Water quality and potential-pollution indices are developed for selected Norwegian drainage basins. The lowest-quality water is in the Mandals and Auli drainage areas, but the Glomma-Gudbrandsdal-Mjosa-Vorma system has the greatest pollution potential. Thus even in a waterrich country such as Norway, water policy is a major concern.  相似文献   

A Systematic Approach to Designing a Multiphase Unsaturated Zone Monitoring Network     

Stephen J. Cullen  John H. Kramer  Jon R. Luellen 《Ground Water Monitoring & Remediation》1995,15(3):124-135

A systematic approach is presented for the design of a multiphase vadose zone monitoring system recognizing that, as in ground water monitoring system design, complete subsurface coverage is not practical. The approach includes identification and prioritization of vulnerable areas: select ion of cost-effective indirect monitoring methods that will provide early warning of contaminant migration: selection of direct monitoring methods for diagnostic confirmation; identification of background monitoring locations; and identification of an appropriate temporal monitoring plan. An example of a monitoring system designed for a solid waste landfill is presented and utilized to illustrate the approach and provide details of system implementation. The example design described incorporates the use of neutron moisture probes deployed in both vertical and horizontal access tubes beneath the lcachate recovery collection system of the landfill. Early warning of gaseous phase contaminant migration is monitored utilizing whole-air active soil gas sampling points deployed in gravel- filled trenches beneath the subgrade. Diagnostic confirmation of contaminant migration is provided utilizing pore- liquid samplers. Conservative tracers can be used to distinguish between chemical species released by a landfill from those attributable to other (e.g. off-site) sources or present naturally in the subsurface. A discussion of background monitoring point location is also presented.  相似文献   

Vadose Zone Monitoring: Experiences and Trends in the United States     

Stephen J. Cullen 《Ground Water Monitoring & Remediation》1995,15(3):136-143

The vadose zone is the portion of the geologic profile above a perennial aquifer. Inclusion of mandatory vadose zone monitoring techniques as an approach to aquifer protect ion was first proposed under the Resource Conservation and Recovery Act in the United States in 1978 and has since received increasing acceptance at federal and stale levels. The goals of a vadose zone characterization and monitoring effort are to establish background conditions, identify contaminant transport pathways, identify the extent and degree of existing contamination, establish the basis for monitoring network design, measure the parameters needed in a risk assessment, and provide detection of contaminant migration toward ground water resources. The benefits of vadose zone monitoring include early warning of contaminant migration, potential reduction of ground water monitoring efforts, reduction of contaminant spreading and volume, and reduced time and cost of remediation once a contaminant release occurs. Vadose zone characterization and monitoring techniques should be considered as critical hydrologic tools in the prevention of ground water resource degradation.  相似文献   

THE APPLICATION OF A MICROCOMPUTER IN THE ANALYSIS OF PUMPING TEST DATA IN CONFINED AQUIFERS     

Peter Dumble  Kevin T. Cullen 《Ground water》1983,21(1):79-83

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A stable oxygen, but not carbon, isotope chronology of Callitris columellaris reflects recent climate change in north-western Australia   总被引：1，自引：0，他引：1  

Louise E. Cullen  Pauline F. Grierson 《Climatic change》2007,85(1-2):213-229

We investigated the dendroclimatic potential of stable carbon (δ¹³C) and oxygen (δ¹⁸O) abundances in tree rings of Callitris columellaris F. Muell. Tree-ring chronologies were constructed from the central Pilbara, north-western Australia and span 1919–1999. Variation in δ¹⁸O was more strongly related to climate than δ¹³C; ecological and physiological factors may have dampened the climate signal in the δ¹³C chronology. Tree-ring δ¹⁸O was most strongly correlated with relative humidity (RH) and rainfall (r = −0.36 and −0.39) of the wettest months of the summer period, January and February. The correlation with RH reflects its effect on evaporative enrichment of leaf water. However, tree-ring δ¹⁸O may also partly reflect the variability in ¹⁸O signatures of rainfall, which are influenced by the amount of rainfall and atmospheric humidity. From the δ¹⁸O chronology, we inferred that from 1919 to 1955 summers were relatively dry and warm, but since 1955, summers in the Pilbara region have become increasingly cooler and more humid. Since 1980, conditions have been the wettest and coolest of the last 80 years. These inferred changes in climate correspond to a measured increase in rainfall since 1980 in north-western Australia associated with a greater intensity of tropical cyclones. We conclude that δ¹⁸O abundances in tree rings of C. columellaris have significant potential for reconstructing the climate of semi-arid Australia, a region for which observational climate records are sparse.  相似文献   

Single-Well Injection-Drift Test to Estimate Groundwater Velocity     

Charles Paradis  Nathan Van Ee  Kendyl Hoss  Cullen Meurer  Aaron Tigar  Paul Reimus  Raymond Johnson 《Ground water》2022,60(4):565-570

A simple algebraic equation is presented here to estimate the magnitude of groundwater velocity based on data from a single-well injection-drift test thereby eliminating the time-consuming and costly extraction phase. A volume of tracer-amended water was injected by forced-gradient into a single well followed by monitoring of the conservative solute tracers under natural-gradient conditions as their upgradient portions drifted back through the well. The breakthrough curve data from the single well during the drift phase was analyzed to determine the mean travel times of the tracers. The estimated mean upgradient travel distance back through the single well and the mean travel times of the tracers were used in a simple algebraic equation to estimate groundwater velocity. The groundwater velocity based on the single-well injection-drift test was estimated to be approximately 0.64 ft per day. Two transects of observation wells were used to monitor the natural-gradient tracer transport downgradient of the injection well. The one-dimensional, or dual-well, transport of the tracer from the injection well to the nearest downgradient observation well indicated that the groundwater velocity was 0.55 ft per day. The two-dimensional, or multi-well, transport of the center of mass of the tracers indicated that the groundwater velocity was 0.60 ft per day; the dual- and multi-well results were in excellent agreement with those from the single-well and validated the simple algebraic equation. The new single-well method presented here is relatively simple, rapid, and does not require an extraction phase.  相似文献