Download or read book Application of Groundwater Tracers and Nitrogen Isotopes in the Evaluation of Septic System Contamination at Washoe Valley Nevada written by W. Alan McKay and published by . This book was released on 1993 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Use of Environmental Tracers and Isotopes to Evaluate Sources of Water Nitrate and Uranium in an Irrigated Alluvial Valley Nebraska written by and published by . This book was released on 2002 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Identifying Sources of Subsurface Nitrate Pollution with Stable Nitrogen Isotopes written by Timothy J. Wolterink and published by . This book was released on 1979 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Strategy for Remediation of Groundwater Contamination at the Nevada Test Site written by and published by Institute of Electrical & Electronics Engineers(IEEE). This book was released on 2001 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Prepared through the collaborative efforts of the American Society of Mechanical Engineers (ASME) Center for Research and Technology Development and the Institute for Regulatory Science ... for the Office of Science and Technology of the U.S. Department of Energy"--T.p. verso.

Download or read book Quantification of the Contribution of Nitrogen from Septic Tanks to Ground Water in Spanish Springs Valley Nevada written by Michael R. Rosen and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Use of Environmental Tracers and Isotopes to Evaluate Sources of Water Nitrate and Uranium in an Irrigated Alluvial Valley Nebraska written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluation of Groundwater Monitoring at Offsite Nuclear Test Areas written by Jenny B. Chapman and published by . This book was released on 1991 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Results of Ground water Tracer Tests Using Tritiated Water at Oak Ridge National Laboratory Tennessee written by D. A. Webster and published by . This book was released on 1996 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Exposure Assessment of Groundwater Transport of Tritium from the Central Nevada Test Area written by Karl F. Pohlmann and published by . This book was released on 1995 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: This exposure assessment provides a range of possible human health risk at two locations due to groundwater transport from the Faultless underground nuclear test. These locations correspond to the boundary of the land under DOE control (where no wells currently exist) and the closest existing well (Six Mile Well). The range in excess risk is within the EPA goal for excess risk due to environmental contaminants (10−6) at Six Mile Well. Calculations considering high spatial variability in hydraulic properties and/or high uncertainty in the mean groundwater velocity are also within the EPA goal. At the DOE boundary, the range in excess risk exceeds the EPA goal, regardless of the values of spatial variability and uncertainty. The range in values of excess risk can be reduced with additional field data from the site; however, incorporation of additional data, which would likely be obtained at great expense, is unlikely to result in significant refinement of the results.

Download or read book Assessing Nitrogen Leaching in Unsaturated Media from Septic Tank Wastes for the North Animas Valley La Plata County Colorado written by Robert F. Carsel and published by . This book was released on 1996 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Rapid Assessment of Potential Ground water Contamination Under Emergency Response Conditions written by Anthony S. Donigian (Jr.) and published by . This book was released on 1984 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluation of Sampling and Field filtration Methods for the Analysis of Trace Metals in Ground Water written by Karl F. Pohlmann and published by . This book was released on 1994 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Using Dissolved Noble Gas and Isotopic Tracers to Evaluate the Vulnerability of Groundwater Resources in a Small High Elevation Catchment to Predicted Climate Changes written by and published by . This book was released on 2009 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: We use noble gas concentrations and multiple isotopic tracers in groundwater and stream water in a small high elevation catchment to provide a snapshot of temperature, altitude, and physical processes at the time of recharge; and to determine subsurface residence times of different groundwater components. They identify three sources that contribute to groundwater flow: (1) seasonal groundwater recharge with short travel times, (2) water from bedrock aquifers that have elevated radiogenic 4He, and (3) upwelling of deep fluids that have 'mantle' helium and hydrothermal carbon isotope signatures. Although a bimodal distribution in apparent groundwater age indicates that groundwater storage times range from less than a year to several decades, water that recharges seasonally is the largest likely contributor to stream baseflow. Under climate change scnearios with earlier snowmelt, the groundwater that moves through the alluvial aquifer seasonally will be depleted earlier, providing less baseflow and possible extreme low flows in the creek during summer and fall. Dissolved noble gas measurements indciate recharge temperatures are 5 to 11 degrees higher than would be expected for direct influx of snowmelt, and that excess air concentrations are lower than would be expected for recharge through bedrock fractures. Instead, recharge likely occurs over diffuse vegetated areas, as indicated by [delta]13C-DIC values that are consistent with incorporation of CO2 from soil respiration. Recharge temperatures are close to or slightly higher than mean annual air temperature, and are consistent with recharge during May and June, when snowpack melting occurs.

Download or read book Methodology to Evaluate the Potential for Ground Water Contamination from Geothermal Fluid Releases written by Karen Summers and published by . This book was released on 1980 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Regional Groundwater Flow and Tritium Transport Modeling and Risk Assessment of the Underground Test Area Nevada Test Site Nevada written by and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The groundwater flow system of the Nevada Test Site and surrounding region was evaluated to estimate the highest potential current and near-term risk to the public and the environment from groundwater contamination downgradient of the underground nuclear testing areas. The highest, or greatest, potential risk is estimated by assuming that several unusually rapid transport pathways as well as public and environmental exposures all occur simultaneously. These conservative assumptions may cause risks to be significantly overestimated. However, such a deliberate, conservative approach ensures that public health and environmental risks are not underestimated and allows prioritization of future work to minimize potential risks. Historical underground nuclear testing activities, particularly detonations near or below the water table, have contaminated groundwater near testing locations with radioactive and nonradioactive constituents. Tritium was selected as the contaminant of primary concern for this phase of the project because it is abundant, highly mobile, and represents the most significant contributor to the potential radiation dose to humans for the short term. It was also assumed that the predicted risk to human health and the environment from tritium exposure would reasonably represent the risk from other, less mobile radionuclides within the same time frame. Other contaminants will be investigated at a later date. Existing and newly collected hydrogeologic data were compiled for a large area of southern Nevada and California, encompassing the Nevada Test Site regional groundwater flow system. These data were used to develop numerical groundwater flow and tritium transport models for use in the prediction of tritium concentrations at hypothetical human and ecological receptor locations for a 200-year time frame. A numerical, steady-state regional groundwater flow model was developed to serve as the basis for the prediction of the movement of tritium from the underground testing areas on a regional scale. The groundwater flow model was used in conjunction with a particle-tracking code to define the pathlines followed by groundwater particles originating from 415 points associated with 253 nuclear test locations. Three of the most rapid pathlines were selected for transport simulations. These pathlines are associated with three nuclear test locations, each representing one of the three largest testing areas. These testing locations are: BOURBON on Yucca Flat, HOUSTON on Central Pahute Mesa, and TYBO on Western Pahute Mesa. One-dimensional stochastic tritium transport simulations were performed for the three pathlines using the Monte Carlo method with Latin hypercube sampling. For the BOURBON and TYBO pathlines, sources of tritium from other tests located along the same pathline were included in the simulations. Sensitivity analyses were also performed on the transport model to evaluate the uncertainties associated with the geologic model, the rates of groundwater flow, the tritium source, and the transport parameters. Tritium concentration predictions were found to be mostly sensitive to the regional geology in controlling the horizontal and vertical position of transport pathways. The simulated concentrations are also sensitive to matrix diffusion, an important mechanism governing the migration of tritium in fractured carbonate and volcanic rocks. Source term concentration uncertainty is most important near the test locations and decreases in importance as the travel distance increases. The uncertainty on groundwater flow rates is as important as that on matrix diffusion at downgradient locations. The risk assessment was performed to provide conservative and bounding estimates of the potential risks to human health and the environment from tritium in groundwater. Risk models were designed by coupling scenario-specific tritium intake with tritium dose models and cancer and genetic risk estimates using the Monte Carlo method. Estimated radiation doses received by individuals from chronic exposure to tritium, and the corresponding human health risks at hypothetical point-of-use locations along each of the pathlines were calculated for six potential land-use scenarios. Conservative land-use scenarios were postulated to ensure that the calculated exposures would bound any realistic dose received by individuals. Based on the human-health risk estimates, tritium exposures associated with the HOUSTON and BOURBON pathlines do not present a human health hazard off the Nevada Test Site in the present, the near term, or in the future. However, the estimates show that the TYBO pathline has the greatest potential for off-site release with a projected groundwater discharge at Oasis Valley. Using the most conservative scenario for tritium exposure demonstrates that dose could exceed the 100-mrem/yr limit at locations along the TYBO pathline.

Download or read book Determining the Source of Nitrate Contamination in Groundwater Using 15 nitrogen as a Tracer written by Kevin Michael Morrissey and published by . This book was released on 1989 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluation Of Groundwater Pathways And Travel Times From The Nevada Test Site To The Potential Yucca Mountain Repository written by J. Chapman and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Yucca Mountain (YM), Nevada, has been recommended as a deep geological repository for the disposal of spent fuel and high-level radioactive waste. If YM is licensed as a repository by the Nuclear Regulatory Commission, it will be important to identify the potential for radionuclides to migrate from underground nuclear testing areas located on the Nevada Test Site (NTS) to the hydraulically downgradient repository area to ensure that monitoring does not incorrectly attribute repository failure to radionuclides originating from other sources. In this study, we use the Death Valley Regional Flow System (DVRFS) model developed by the U.S. Geological Survey to investigate potential groundwater migration pathways and associated travel times from the NTS to the proposed YM repository area. Using results from the calibrated DVRFS model and the particle tracking post-processing package MODPATH, we modeled three-dimensional groundwater advective pathways in the NTS and YM region. Our study focuses on evaluating the potential for groundwater pathways between the NTS and YM withdrawal area and whether travel times for advective flow along these pathways coincide with the prospective monitoring timeframe at the proposed repository. We include uncertainty in effective porosity, as this is a critical variable in the determination of time for radionuclides to travel from the NTS region to the YM withdrawal area. Uncertainty in porosity is quantified through evaluation of existing site data and expert judgment and is incorporated in the model through Monte Carlo simulation. Since porosity information is limited for this region, the uncertainty is quite large and this is reflected in the results as a large range in simulated groundwater travel times.