Harold W. Bentley, Ph.D.
Principal Scientist

 

Expertise

• Principal Investigator for SBIR grant to develop redox catalytic system to remove organic and halogenated volatile compounds from gas streams.

• Managed on-site and regional-scale tracer tests in karst terrane limestones, north coast Puerto Rico. Dye tracers (sodium fluorescein), conservative tracers (fluorinated acids, sulfonic acids) and environmental tracers (chloride/bromide ratios) were used to identify extent and hazard potential of contaminant plume. Project included hydrogeologic investigation, on-site tracer analysis, well tests, and groundwater modeling. Was selected by USEPA to conduct community public information meeting. The study resulted in USEPA modification of ROD to recommendation of “No further action”.

• Managed baro-pneumatic, landfill gas measurement at 30-acre landfill in Layfayette, LA. Numerical model was used to analyze landfill response (in 20 probes) to diurnal variation in barometric pressure. Results of the test included LFG measurement and calibrated 1st order decay model predicting future LFG production.

• Principal-in-charge of aerobic landfill pilot studies in Tucson, Arizona. Initial test was conducted in heavily instrumented 100-foot square area; second test was 3-acre portion. Air was injected and withdrawn; moisture and energy balances and settling were used to assess biodegradation rates and completion of MSW treatment.

• Principal investigator for identification and development of a water treatment system for N-nitrosodimethylamine (NDMA) in groundwater. This investigation required numerical simulation and optimization of an ultraviolet reactor and laboratory studies of system performance. Subsequent field pilot studies verified the highly efficient performance of the reactor in treating NDMA and equivalently high performance in advanced UV oxidation of other organic species. Process was successfully commercialized and sold to large UV equipment firm.

• Principal Scientist for evaluation of non-methane organic compound mass emissions from State Route 85 Regional Landfill in Phoenix Arizona. NMOC emissions were estimated based on numerical modeling that considered losses by vapor extraction (associated with landfill gas evolution and discharge to atmosphere and LFG collection); anaerobic biodegradation within the refuse; and aerobic and methanotrophic oxidation within the 3-foot permeable cover.

• Developed (with B. Travis, Los Alamos National Laboratories) a 3-dimensional saturated-unsaturated zone numerical model (TRAMP) for evaluating the role of enhanced biodegradation in remediating soils and groundwater contaminated with organic constituents. Applied model to evaluation of bioventing/biodegration cleanup of unsaturated zone impacted by leaking VOC-contaminated mound and cleanup of regional groundwater aquifer. Performed and interpreted tracer tests and column studies evaluating rates of biodegradation in air-stimulated unsaturated soils. Model has subsequently been used in a number of projects, including the biodegradation model used in the DOE/USEPA Savannah River demonstration project for the soil vapor extraction of chlorinated ethenes, simulation of biosparging at a number of remediation sites, aerobic landfill biodegradation, and landfill NMOC attenuation.

• Project manager for baro-pneumatic analysis of LFG production and design of a methane-migration control system at a closed landfill in central Georgia.

• Project manager for feasibility study of SVE at Superfund site in Syracuse, New York. The project included a quantitative evaluation of the relative roles of diffusion and advection in affecting SVE remediation. Project resulted in USEPA overturning Record of Decision mandating thermal treatment and accepting our recommended, much less expensive soil vapor extraction as alternative ROD.

• Principle contributor to development of methodology employing halogen isotopes as environmental tracers. These included the radionuclides 36Cl and 129I, and the stable chlorine ratio 37Cl:35Cl, all of which have subsequently been widely used for hydrogeologic characterization.

• Used 36Cl as environmental tracer to investigate source of salinity in shallow groundwaters and soils in the "Drought Polygon" and in the Amazon delta in N.E. Brazil. Client: International Atomic Energy Agency.

• Used chlorine isotopes as environmental groundwater tracers to construct a conceptual model of flow in the Columbia River Flood Basalts and make preliminary estimates of residence times for Rockwell-Hanford, Basalt Waste Isolation Project (BWIP); to develop a preliminary conceptual model of recharge and flow in the unsaturated zone at Yucca Mountain, Nevada; and with F. Phillips, to develop a conceptual model of geothermal flow at Valles Caldera, New Mexico.

• Used environmental tracers to determine contaminant plumes from flue-gas desulfurization waste pond and blow-down waters holding pond in multi-aquifer system, Rock Springs, Wyoming. Performed similar tracer studies for utility company in western Wyoming and at uranium mine tailings pond in New Mexico.

• Evaluated Rustler Formation aquifers at the Waste Isolation Pilot Plant. Consulted on tracer development and conducted groundwater tracer tests. Project included evaluation of anisotropy, porosity, and conduit flow in fractured rock system, and determination of sources and residence times of waters through isotopic and chemical methods.

• Project manager for feasibility study of SVE at Superfund site near Cincinnati, Ohio (resulting in overturning U.S. Environmental Protection Agency (EPA) Record of Decision mandating in-situ vitrification); managed remedial action/remedial design predesign investigation and conceptual engineering design of the accepted alternative, a vacuum-dewatering/SVE system.

• Remediation conceptual design and simulation for in-situ vacuum extraction of volatile organics and soil flushing at Michigan Superfund site, volatile organics at Indiana Superfund site, and volatile organic halocarbons at industrial site in California. Also, bioventing at Wyoming Superfund site (target: polycyclic aromatic hydrocarbons) and industrial site in Texas (target: benzene and mixed organics).

• Conducted critical review of EPA Superfund Remedial Investigation/Feasibility Study studies at Western Processing, Kent, WA, and LDI site, Michigan.

• Designed HGC’s soil gas sampling and analysis methodology: in-field gas collectiona and analysis using modified EPA Method 8021 for chlorinated and aromatic VOCs.

• Oversaw a number of soil gas investigations involving landfills, plumes of chlorinated solvents, leaking tanks of petroleum products, and solvent spills.

• Chaired the session on physical and chemical characteristics of fractured tuff at 1986 Nuclear Regulatory Commission (NRC) sponsored workshop, Tucson, Arizona.

• Chaired session on groundwater travel time for Gain-84, the Geotechnical Assessment and Instrumentation Needs for Isolation of Nuclear Wastes in Crystalline Rocks, an Office of Nuclear Waste Isolation sponsored workshop.

• Chaired session on microbial transport for DOE workshop on fate and transport of groundwater microbes related to deep biodegradation processes, Delaware.

• Evaluated uranium mining impact on the water resources of the Pueblo of Laguna. Developed the use of sulfur isotopes to trace leakage from uranium tailings ponds. Evaluated heavy metal transport under acid conditions.

• Contributed overview and initial design of Rockwell International's geochemistry program regarding potential nuclear waste disposal in the deep aquifers at BWIP, Hanford, Washington.

• Evaluated migration of radionuclides from Cambric underground nuclear test at the Nevada Test Site (for Los Alamos National Laboratory).

• Investigated and designed in-situ remediation of chromium contamination at a hazardous waste site in Casa Grande, Arizona. Project resulted in complete in-situ reduction of Cr(VI) to Cr(III). Also evaluated organic contamination in the groundwater in the vicinity of the site.

Expert Witness Experience

• Represented U.S. Justice Department in U.S. vs. Royal N. Hardage et al. Provided expert testimony regarding use of SVE to remove VOCs from soil.

• Evaluated impact of stream flow on dewatering operation in Pima County, Arizona. Case settled prior to deposition process.

• Evaluated and presented testimony regarding potential contaminant impact of Pima County municipal waste landfill on groundwater. Project included assessment of generation, transport and fate of contaminant species, and assessment of leachate produced prior to landfill closure.

• Evaluated potential impact of second Pima County municipal waste landfill operation on groundwater.

• Represented private sector client in Concord, California. Case involved allocation of costs for remediation of multi-source petroleum product soil contamination.

• Represented private sector client in Kent, Washington. Analyzed USEPA Superfund Site Remedial Investigation and Feasibility Assessment; showed that USEPA and its consultants had neglected to account for migration of organic and inorganic contaminants to soils and groundwater underlying client-owned adjacent property. Case settled in favor of client.

Prior Experience

• Associate Adjunct Professor at the University of Arizona, Department of Hydrology and Water Resources from 1985-1993. Assistant Research Professor from 1979 to 1984. Teaching responsibilities included Water Quality Dynamics, a graduate course in hydrogeochemistry and groundwater contamination. Area of research: the use of isotopes and chemical constituents for dating, tracing, and identifying sources and assessing flow of groundwater. Co-principal investigator with S.N. Davis on ONWI funded study on the viability of the use of 36Cl as a dating tool for old groundwaters. Principal investigator on study of isotopes to quantify leakage from tailings pond into groundwater, an Office of Water Resources funded study. Co-principal investigator on NRC-AAEC funded study of tandem mass-accelerator investigation of radionuclides from uranium ore deposits. Principal investigator on design and development of fluorinated anions as groundwater tracers. Cooperative investigator with F. Phillips, New Mexico Institute of Mining and Technology, on (1) investigation of sources of salinity in Antarctica dry valley lakes and (2) Use of sorbing tracers to evaluate lixiviant contact with copper ore deposits.

• Joined Department of Hydrology, University of Arizona in 1977 as Masters candidate. From 1977 to 1978 was graduate research associate. Masters work included the development of 36Cl as a groundwater dating method and the development of fluorinated organic acids as groundwater tracers. From 1970 to 1976 held postdoctoral appointments in the Department of Chemistry and the Department of Agricultural Biochemistry, University of Arizona. Chemical oceanographer at Woods Hole Oceanographic Institution from 1963 to 1967.

PROFESSIONAL PUBLICATIONS:

Bentley, H.W., 2004. Baro-pneumatic Method of Estimating Landfill Gas Generation Rates. Abstracts with Program, Annual Conference on Waste and the Environment. March 17 – 19, 2004, Lafayette, Louisiana.

Walter, G.R., A.M. Geddis, R. Murray, and H.W. Bentley, 2003. Vapor-phase transport as a groundwater contamination process. Proceedings of the 18th International Conference on Solid Waste Technology and Management, Philadelphia, Pennsylvania, March 23-26, 2003.

Bentley, H.W., S. Smith, J. Tang, and G.R. Walter, 2003. A Method for Estimating the Rate of Landfill Gas Generation by Measurement and Analysis of Barometric Pressure Waves. Proceedings of the 18th International Conference on Solid Waste Technology and Management, Philadelphia, Pennsylvania, March 23-26, 2003.

Bentley, H. W., G. R. Walter. S. J. Smith., J. Tang, and C.T. Williamson. June 19, 2002. (US) Patent No. US 6,611,760 B2 Method and system for estimating gas production by a landfill or other subsurface source.

Walter, G.R., S. Smith, J. Tang, and H.W. Bentley, 2002. Comparison of direct techniques for estimating LFG generation rates. Abstracts with Program. SWANA Regional Landfill Conference, Casa Grande, AZ.

Walter, G.R., S. Smith, H.W. Bentley, and J. Tang, 2002. The Baro-pneumatic Method: A Proposed Alternative to The EPA Tier 3 Method For Measurement of Landfill Gas Generation. White Paper Submitted to USEPA Office of Air Quality, Research Triangle Park, North Carolina.

Bentley, H.W. and S. Smith. 1998. Soil Vapor Extraction of Chlorinated VOCs in the Vicinity of a Landfill Equipped with a Landfill Gas Control System. Presented at the 1998 Arizona Hydrological Society Eleventh Annual Symposium. September 23-26, 1998. Abstract with Proceedings.

Bentley, H.W., J. Tang, S. Smith, D. Samorano, and R.G. Arnold. 1998. Analysis of Remedial Options for Chlorinated and Recalcitrant Compounds. In: Bioremediation and Phytoremediation Chlorinated and Recalcitrant Compounds. The First International Conference on Remediation of Chlorinated and Recalcitrant Compounds. Monterey, California. May 18-21, 1998. pp. 21-26.

Bentley, H.W. and B. Travis. 1991. Modeling in-situ biodegradation in unsaturated and saturated soils. (Invited paper.) Proceedings of the EPA conference on Soil Vapor Extraction, Houston, Texas, April 29-May 1, 1991.

Walter, G.R., and H.W. Bentley. 1991. Use of soil gas measurements in the design of soil vapor extraction systems. (Invited paper.) Proceedings of the U.S. Environmental Protection Agency Conference on Soil Vapor Extraction, Houston, Texas, April 29- May 1, 1991.

Carlson, C.A., F.M. Phillips, D. Elmore, and H.W. Bentley. 1989. Chlorine-36 tracing of salinity sources in the dry valleys of Victoria Land, Antarctica. Geochim. Cosmochim Acta.

Walter, G.R., H.W. Bentley, V.K. Gupta, and J. Carrera. 1987. Computer Assisted Site Investigation and Management: A Tool for Assessing and Managing Groundwater Contamination. In Proceedings of the National Water Well Association Conference on Solving Ground Water Problems with Models, Denver, Colorado.

Walter, G.R. and H.W. Bentley. 1986. The value and pitfalls of numerical modeling applied to groundwater contamination investigations. In Proceedings of a Symposium on Current Practices for Hazardous Waste Management in Arizona, Phoenix, Arizona.

Adams, M.C., J. Ahn, H.W. Bentley, and J.N. Moore. 1986. Tracer developments: results of experimental studies. Proceedings of the 11th Workshop on Geothermal Reservoir Engineering, Stanford, California.

Adams, M.C., J. Ahn, J.N. Moore, and H.W. Bentley. 1985. Geothermal tracer research. Poster session, Geothermal Resources Council, August 28, 1989.

Bentley, H.W., G.R. Walter, and M.W. Kuhn. 1985. Ground water modeling in contamination assessment: Application to FGD pond leakage. Proceedings of the Edison Electric Institute Groundwater Workshop, New Orleans.

Bentley, H.W., F.M. Phillips, S.N. Davis, M.A. Habermehl, P.L. Airey, G.E. Calf, D. Elmore, H.E. Gove, and T. Torgersen. 1986. Chlorine-36 dating of very old ground water I: The Great Artesian Basin, Australia, Water Resources Research.

Phillips, F.M., H.W. Bentley, S.N. Davis, D. Elmore, and G.B. Swanick. 1986. Chlorine-36 dating of very old ground water II: Milk River Aquifer, Canada. Water Resources Research.

Phillips, F.M. and H.W. Bentley. 1986. Isotopic fractionation during ion filtration I. Theory. Submitted to Geochim. Cosmochim Acta.

Norris, A.E., K. Wolfsberg, H.W. Bentley, and S.K. Gifford. 1985. The use of 36Cl for infiltration measurements at Yucca Mountain, Nevada. Proceedings of the Accelerator-based Mass Spectrometry Symposium, American Chemical Society National Meeting, Chicago, Illinois, Sept. 8-13, 1985.

Phillips, F.M., F. Goff, F. Vautaz, H.W. Bentley, D. Elmore, and H.E. Gove. 1985. 36Cl as a tracer in geothermal systems: example from Valles Caldera, New Mexico. Geophysical Research Letters.

Fabryka-Martin, J., H.W. Bentley, D. Elmore, and P.L. Airey. 1985. Natural iodine-129 as an environmental tracer, Geochimica et Cosmochimica Acta 49, pp. 337-347.

Gifford, S., H.W. Bentley, and D. Graham. 1985. Use of chlorine isotopes as environmental tracers in the Columbia River Basalts. Part I: Proceedings of a Symposium on the Hydrogeology of Rocks of Low Permeability, University of Arizona, Tucson, Arizona, pp. 417-429.

Phillips, F.M., G.I. Smith, H.W. Bentley, D. Elmore, and H.E. Gove. 1984. 36Cl dating of saline sediments: preliminary results from Searles Lake, California. Science 222 pp. 41-43.

Carrera, J., G.R. Walter, M.W. Kuhn, H.W. Bentley, and G. Swanick. 1984. Three-dimensional modeling of saline pond leakage calibrated by INVERT-3, a quasi-three-dimensional, transient, parameter-estimation program. Proceedings of the 1984 Conference on Practical Applications of Ground-Water Modeling, NWWA, Worthington, Ohio.

Kaufmann, R., A. Long, H.W. Bentley, and S. N. Davis. 1984. Natural Chlorine Isotope Variations. Nature 309, pp. 338-340.


Kuhn, M.W., S.N. Davis, H.W. Bentley, and R. Zito. 1984. Measurements of thermal neutrons in the subsurface. Geophys. Res. Letters, 11, pp. 607-610.

Neuman, S.P., G.R. Walter, H.W. Bentley, J.J. Ward, and D.D. Gonzalez. 1984. Determination of horizontal aquifer anisotropy with three wells. Ground Water 22, pp. 66-72.

Wolfsberg, K., P.L. Wanek, K.S. Daniels, S.L. Fraser, R.S. Rundberg, J.L. Thompson, W.R. Daniels, H.W. Bentley, D. Elmore, L.E. Tubbs, and J. Fabryka-Martin. 1984. The migration of 129I and 36Cl from an underground nuclear-explosion cavity under forced conditions. Amer. Chem. Soc. Symp., St. Louis, MO.

Kaufmann, R., H.W. Bentley, S. Davis, and A. Long. 1983. Application of chloride stable isotope analysis to hydrogeology. Hydrology and Water Resources in Arizona and the Southwest, Volume 13, Proceedings of the 1983 Meetings of the Arizona Section, AWRA.

Michelot, J.L., H.W. Bentley, I. Brissaud, D. Elmore, J. Ch. Fontes. 1983. Progress in environmental isotopes studies 36Cl, 34S, 18O on the Stripa Site. International Symposium on Isotope Hydrology in Water Resources Development, Vienna, Austria, 12-16 September (IAEA).

Bentley, H.W. 1983. Development and use of groundwater tracers at the Waste Isolation Pilot Plant, Southeastern New Mexico. EOS (abs), 64.

Walter, G.R., H.W. Bentley, J.J. Ward and D.D. Gonzalez. 1983. Continuum and non-continuum aspects of groundwater movement at the Waste Isolation Pilot Plant, Southeastern New Mexico. EOS (abs), 64.

Airey, P.L., H. Bentley, G. Calf, S.N. Davis, D. Elmore, H. Gove, M.A. Habermehl, F. Phillips, J. Smith, and T. Torgeson. 1983. Isotope hydrology of the Great Artesian Basin. Proc. Int. Conf. on Groundwater and Man (Sydney, Australia), Vol. 1, 1.

Bentley, H.W., F.M. Phillips, S.N. Davis, S.K. Gifford, D. Elmore, L.E. Tubbs, H. Gove. 1982. Thermonuclear Cl-36 pulse in natural water. Nature 300 23/30 December, pp. 737-740.

Thurnblad, T.W., H.W. Bentley, and D.K. Kreamer. 1982. An evaluation of the effectiveness of hydrogen and oxygen isotopes used in concert with chemical water-quality parameters as indicators of subsurface water movement and source, A completion report for the Office of Water Research and Technology, U.S.D.O.I., Proj. No. 1-103-ARIZ, University of Arizona.

Bentley, H.W. and S.N. Davis. 1982. Application of accelerator mass spectrometry to hydrology. Proceedings of the Second Annual AMS Symposium, Argonne National Laboratories, Ed., W. Kuchera. (Also an invited paper.)

Wolfsberg, K., P.L. Wanek, H.W. Bentley, and D. Elmore. 1981. Chlorine-36 in Cambric waters: 2. Determination of Cl-36 and I-129 in RNM water samples. Laboratory and field studies related to the radio nuclide migration project-annual report, Oct 12, 1980-Sept. 30, 1981, W.R. Daniels, ed. Los Alamos National Laboratory.

Bentley, H.W. and S.N. Davis. 1980. Feasibility of Cl-36 dating of very old groundwater. American Geophysics Union, EOS v. 61, no. 17, p. 230.

Bentley, H.W. and S.N. Davis. 1980. Isotope geochemistry as a tool for determining groundwater flow. Proceedings of the 1980 Natl. Waste Terminal Storage Program Information Meeting, Columbus, Ohio, ONWI-212.

Finkel, R.C., K. Nishiizumi, D. Elmore, R.D. Ferraro, H.E. Gove, and H.W. Bentley. 1980. Cl-36 in Polar ice, rainwater, and seawater. University of Rochester Nuclear Structure Research Laboratory UR-NSRL-225, August, 1980.

Zito, R., D.J. Donahue, S.N. Davis, H.W. Bentley, and P. Fritz. 1980. Possible subsurface production of carbon-14. Geophysical Research Letters, V. 7, No. 4, pp. 235-238.

Davis, S.N., G.M. Thompson, H.W. Bentley, and G. Stiles. 1980. Groundwater tracers - a short review. Ground Water v. 18, no. 1, pp 14-23.

Davis, S.N., G.M. Thompson, and H.W. Bentley. 1979. Methods of groundwater dating. Geo. Soc. of America, Abst. with Programs, v. 11, no. 3, p. 74.

Bentley, H.W. 1978. Some comments on the use of chlorine-36 for dating very old groundwater. Workshop on Dating Old Ground Water. S.N. Davis, ed. University of Arizona, Department of Hydrology and Water Resources.

BOOK CHAPTERS AND MANUALS:

Bentley, H.W., D. L. Marin, and C. Cooper. Innovative Soil Gas Monitoring and Remediation Applications, 1997. Manual Provided by Groundwater Resources Association of California Seminar Series (Short Course). McClelland Air Force Base, Sacramento, CA, Sept. 24, 1997 and Wyndham Garden Hotel, Costa Mesa, CA, Sept. 25, 1997.

Kaufmann, R., S.K. Frape, P. Fritz, and H.W. Bentley, 1987. Chlorine stable isotope composition of Canadian Water and Gases in Crystalline Rocks. P. Fritz and S. Frape, Geological Association of Canada Special Paper 33, Runge Press Ltd, Ottawa Canada, pp. 89-94.

Bentley, H.W., F. Phillips, and S.N. Davis. 1986. Chlorine-36 in the Terrestrial Environment. Handbook of Environmental Isotope Geochemistry, v. Ib, Ed. J.C. Fontes and P. Fritz, Elsevier, Amsterdam, pp. 422-475.

Davis, S.N., D.J. Campbell, H.W. Bentley, and T.J. Flynn. 1985. Groundwater Tracers. National Water Well Association, Worthington, Ohio.

Gonzalez, D.D. and H.W. Bentley. 1984. Field test for effective porosity and dispersivity in fractured dolomite, the WIPP, Southeastern New Mexico. In Groundwater Hydraulics, the Water Resources Monograph Series, Ed. J.S. Rosenshein and G.D. Bennett, American Geophysical Union.

Davis, S.N. and H.W. Bentley. 1981. Groundwater dating, a short review. In ACS Symposium Series, American Chemical Society, Washington, D.C.

INVITED PAPERS AND TALKS:

Bentley, H.W., S.J. Smith, and T. Schrauf, 2004. Baro-pneumatic Estimation of landfill gas generation rates at four operating landfills. Presentation at 3rd Intercontinental Landfill Research Symposium, Hokkaido, Japan November 29-December 2, 2004.

Bentley, H.W. 1992. Design and performance of vapor extraction pilot studies. Seminar on Vapor Extraction for Soil Cleanup. California Regional Water Quality Control Board, Los Angeles Region. Monterey Park, California, August 12, 1992.

Bentley, H.W. 1992. The design and application of groundwater tracers. Invited speaker, Pittsburgh Geologic Society, Pittsburgh Pennsylvania. April 21, 1992.

Bentley, H.W. 1992. Hydrogeologic modeling and applications to soil and groundwater remediation. New York Department of Environmental Conservation. Albany, New York. January 30, 1992.

Bentley, H.W. and B.R. Travis. 1991. Simulation of SVE-enhanced biodegradation in unsaturated and saturated soils. Symposium of Soil Vapor Extraction and Bioventing, U.S. Environmental Protection Agency. Houston, Texas, April 30, 1991.

Bentley, H.W. 1991. Soil gas surveys: theory and practice. Seminar on Soil Gas Surveys for Assessment of Soils Contamination. California Regional Water Quality Control Board--Los Angeles Region. Monterey Park, California. November 1991.

Bentley, H.W. and G.R. Walter. 1986. Use of soil gas measurements to derive soil mass concentrations of volatile organic compounds. Symposium on Current Waste Handling Practices, Arizona Hydrologic Society, Phoenix, October 23, 1986.

Bentley, H.W. 1983. The dating of old and young groundwaters with Cl-36 and I-129. United States Geological Survey, Menlo Park, California, April 6, 1983.

Bentley, H.W. 1982. Salinity sources in the "Drought Polygon", N.E. Brazil. International Atomic Energy Association sponsored lectures at Centro de Energia Nuclear na Agricultura, Aug 15-16, 1982.

Bentley, H.W., and S. Alweis. 1982. Use of sulfur isotopes to evaluate groundwater contamination by mining and industrial processes. ACS Symposium on the Hydrology of Mining and Industrial Wastes, El Paso, Dec. 2, 1982.

Bentley, H.W. 1982. Selection of tracers for evaluation of aquifer parameters. ACS Symposium on the Hydrology of Mining and Industrial Wastes, El Paso, Texas, Dec. 2, 1982.

Bentley, H.W. and S.N. Davis. 1982. Applications of Cl-36 to the hydrology of nuclear waste. Presented at the Symposium on the Geochemistry of Nuclear Waste Disposal, Las Vegas, March 29-April 2, 1982.

Bentley, H.W. 1982. Uses of Cl-36 in hydrology. Australian Geological Society Meetings, Brisbane, May 17, 1982.

Bentley, H.W. and S.N. Davis. 1982. Cl-36 as a groundwater dating tool and environmental tracer. American Geophysical Union Symposium on Isotope Studies of Hydrologic Processes, Northern Illinois University.

 

 

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