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HYDROCARBON VAPOR DIFFUSION IN INTACT CORE SLEEVES

GROUND WATER MONITORING AND REMEDIATION 1993年第1期13卷 139-150页

作者： OSTENDORF, DW MOYER, EE XIE, YF RAJAN, RV David W. Ostendorf (Civil Engineering Department University of Massachusetts Amherst MA 01003) is an associate professor in the Environmental Engineering Program of the Civil Engineering Department of the University of Massachusetts at Amherst. His research interests include unconfined aquifer contamination hazardous waste site remediation and analytical modeling of problems in environmental fluid mechanics. Ostendorf is a Registered Professional Engineer in Massachusetts and a member of the American Geophysical Union American Society of Civil Engineers Soil Science Society of America Water Pollution Control Federation and Association of Environmental Engineering Professors as well as the National Ground Water Association. Ellen E. Moyer (Civil Engineering Department University of Massachusetts Amherst MA 01003) is a doctoral candidate in the Environmental Engineering Program of the Civil Engineering Department of the University of Massachusetts at Amherst with an M.S. degree in environmental engineering from that institution. Her research interests include subsurface investigation soil venting bioremediation and analytical modeling of subsurface contamination. She has six years of professional experience managing hazardous waste site investigation and cleanup projects and is a member of the National Ground Water Association and the American Society of Civil Engineers. Yuefeng Xie (Civil Engineering Department University of Massachusetts Amherst MA 01003) is a postdoctoral research associate in the Environmental Engineering Program of the Civil Engineering Department of the University of Massachusetts at Amherst. His research interests include environmental analyses drinking water treatment and the chemical characterization and removal of disinfection by-products. A graduate with a Ph.D. and an M.S. in environmental engineering and a B.S. in chemistry and chemical engineeering from Tsinghua University Beijing China Xie is a member of the American Water Works Association and the Water Poll

The diffusion of 2,2,4-trimethylpentane (TMP) and 2,2,5-trimethylhexane (TMH) vapors out of residually contaminated sandy soil from the U.S. environmental Protection Agency (EPA) field research site at Traverse City, Michigan, was measured and modeled. The headspace of an intact core sleeve sample was swept with nitrogen gas to simulate the diffusive release of hydrocarbon vapors from residual aviation gasoline in and immediately above the capillary fringe to a soil-venting air flow in the unsaturated zone. The resulting steady-state profile was modeled using existing diffusivity and air porosity estimates in a balance of diffusive flux and a first order source term. The source strength, which was calibrated with the observed flux of 2,2,4-TMP leaving the sleeve, varied with the residual gasoline remaining in the core, but was independent of the headspace sweep flow rate. This finding suggested that lower soil-venting air flow rates were in principle as effective as higher air flow rates in venting LNAPL vapors from contaminated soils. The saturated vapor concentration ratio of 2,2,4-TMP to 2,2,5-TMH decreased from 6.6 to 3.5 over the duration of the experiments in an expression of distillation effects. The vertical profile model was tested against sample port data in four separate experiments for both species, yielding mean errors ranging from 0 to -24 percent in magnitude.

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AN OVERVIEW OF IN-SITU AIR SPARGING

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GROUND WATER MONITORING AND REMEDIATION 1993年第4期13卷 127-135页

作者： JOHNSON, RL JOHNSON, PC MCWHORTER, DB HINCHEE, RE GOODMAN, I Dr. Richard L. Johnson is an associate professor in the Department of Environmental Science and Engineering at the Oregon Graduate Institute (P.O. Box 91000 Portland OR 97291). He is also the director of the OGI Center for Groundwater Research and the OGI Large Experimental Aquifer Program. Dr. Paul C. Johnson is a senior research engineer at Shell Development Co. (Westhollow Research Center P.O. Box 1380 Houston TX 77251). Dr. David B. McWhorter is a professor in the Department of Agricultural and Chemical Engineering at Colorado State University (Engineering Research Center Foothills Campus Fort Collins CO 80523). Dr. Robert Hinchee is a research leader in the Environmental Technology Department at Battelle Memorial Institute (505 King Ave. Columbus OH 43201). Iris Goodman is an environmental scientist with the Advanced Monitoring Systems Division at the U.S. EPA Environmental Monitoring Systems Laboratory (P.O. Box 93478 Las Vegas NV 89192).

In situ air sparging (IAS) is becoming a widely used technology for remediating sites contaminated by volatile organic materials such as petroleum hydrocarbons. Published data indicate that the injection of air into subsurface water saturated areas coupled with soil vapor extraction (SVE) can increase removal rates in comparison to SVE alone for cases where hydrocarbons are distributed within the water saturated zone. However, the technology is still in its infancy and has not been subject to adequate research, nor have adequate monitoring methods been employed or even developed. Consequently, most IAS applications are, designed, operated, and monitored based upon the experience of the individual practitioner. The use of in situ air sparging poses risks not generally associated with most practiced remedial technologies: air injection can enhance the undesirable off-site migration of vapors and ground water contamination plumes. Migration of previously immobile liquid hydrocarbons con also be induced. Thus, them is an added incentive to fully understand this technology prior to application. This overview of the current state of the practice of air sparging is a review of available published literature, consultation with practitioners, a range of unpublished data reports, as well as theoretical considerations. Potential strengths and weaknesses of the technology are discussed and recommendations for future investigations given.

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EPAS APPROACH TO VADOSE ZONE MONITORING AT RCRA FACILITIES

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GROUND WATER MONITORING AND REMEDIATION 1993年第1期13卷 151-158页

作者： DURANT, ND MYERS, VB ECCLES, LA Washington D.C. 20460) has worked as an environmental scientist in the RCRA corrective action program at EPA since 1989. After graduating from Colgate University in 1987 Durant worked for GeoTrans Inc. conducting hydrogeologic investigations at numerous waste disposal sites throughout the northeastern United States. At present Durant is pursuing an M.S. degree in environmental science from The Johns Hopkins University. His research is focused on enhancing in situ biodegradation of aromatic organic compounds in the subsurface. Washington D. C. 20460) graduated from The Johns Hopkins University in 1972 with a B.A. degree in natural sciences. Myers received a Ph.D. in oceanography from Florida State University in 1977. During 1978 he held a post doctoral fellowship at University of Florida in the Department of Environmental Engineering and Science. From 1979 to 1983 Myers was employed by the Florida Department of Environmental Regulation where he worked on environmental restoration projects. Since 1984 Myers has worked at EPA managing RCRA ground water monitoring and corrective action programs. Lawrence A. Eccles (U.S. Environmental Protection Agency Environmental Monitoring Systems Laboratory P.O. Box 93478 Las Vegas NV 89193–3478) is a hydrologist with the EPA Environmental Monitoring Systems Research Laboratory in Las Vegas Nevada. Eccles is responsible for the development of vadose zone and in situ monitoring techniques and guidelines. After graduating from Monmouth College with a B.S. degree in chemistry Eccles performed graduate work in chemical engineering at New Mexico State University. He received formal training in hydrology in 1969 from the U.S. Geological Survey in Denver and worked with that agency before joining EPA at Las Vegas in 1984. One of his co-authored articles was chosen for the Best Paper Award by the journal Ground Water in 1975 and another was the subject of a cover story for Water Well Journal in 1977.

The U.S. environmental Protection Agency (EPA) recently proposed to amend federal regulations to require vadose zone monitoring at certain hazardous waste facilities. To support this proposal, EPA evaluated previous policy on vadose zone monitoring and examined advances in vadose zone monitoring technology. Changes in EPA vadose zone monitoring policy were driven by demonstrated advances in the available monitoring technology and improvements in understanding of vadose zone processes. When used under the appropriate conditions, currently available direct and indirect monitoring methods can effectively detect contamination that may leak from hazardous waste facilities into the vadose zone. Direct techniques examined include soil-core monitoring and soil-pore liquid monitoring. Indirect techniques examined include soil-gas monitoring, neutron moderation, complex resistivity, ground-penetrating radar, and electrical resistivity. Properly designed vadose zone monitoring networks can act as a complement to saturated zone monitoring networks at numerous hazardous waste facilities. At certain facilities, particularly those in arid climates where the saturated zone is relatively deep, effective vadose zone monitoring may allow a reduction in the scope of saturated zone monitoring programs.

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CONTRIBUTION OF BENTHIC BLUE-GREEN-ALGAL RECRUITMENT TO LAKE POPULATIONS AND PHOSPHORUS TRANSLOCATION

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FRESHWATER BIOLOGY 1992年第2期27卷 249-260页

作者： BARBIERO, RP WELCH, EB Environmental Engineering & Science Program Department of Civil Engineering University of Washington Seattle WA U.S.A.

1. A two-season investigation was undertaken to determine the contribution of benthic recruitment to the population development of several species of blue-green algae. 2. Gloeotrichia echinulata populations were shown to be heavily subsidized by benthic recruitment, deriving on average 40% of their planktonic colonies from the benthos. 3. Benthic recruitment of Aphanizomenon flos-aquae;Anabaena flos-aquae and a second Anabaena species contributed less than 2% to planktonic increases, while Microcystis aeruginosa recruitment was negligible. 4. Phosphorus translocation via migrating G. echinulata accounted for most of the phosphorus (P) in the planktonic colonies, and constituted a significant portion of the internal loading of the lake. 5. Estimated P translocation via Aph. flos-aquae was relatively minor, although there was evidence of luxury uptake in the benthos.

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COMPARISON OF STAINLESS-STEEL VS PTFE MINIWELLS FOR MONITORING HALOGENATED ORGANIC SOLUTE TRANSPORT

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GROUND WATER MONITORING AND REMEDIATION 1992年第4期12卷 126-131页

作者： BIANCHIMOSQUERA, GC MACKAY, DM Gino Bianchi-Mosquera (51 Claremont Ave. Long Beach CA 90803) is a project geochemist with Watkins-Johnson Environmental Inc. He received a B.A. degree in geochemistry from Occidental College Los Angeles California an M.S. degree in geochemistry from The Pennsylvania State University and a D.Env. degree from the University of California Los Angeles in 1982 1986 and 1992 respectively. His research interests include the transport and fate of organic compounds in the subsurface and in the evaluation of new aquifer cleanup techniques. Douglas Mackay is adjunct professor in the Centre for Groundwater Research at the University of Waterloo (Waterloo Ontario N2L3G1) Canada and a visiting scientist at the UCLA Department of Civil Engineering. From 1986 to mid-1990 he was a faculty member in the Environmental Science and Engineering Program of the UCLA School of Public Health. His research focuses on field studies of transport and fate of organic chemicals in ground water and ground water decontamination technologies. Dr. Mackay received a B.S. in engineering and M.S. and Ph.D. degrees in civil engineering from Stanford University in 1970 1973 and 1981 respectively.

Field tests of organic solute transport behavior have often been monitored using small-diameter wells (miniwells). To determine if experimental results could be significantly biased by sorption to, desorption from, or diffusion through sampling lines, dissolved concentrations of tetrachloroethene and carbon tetrachloride were measured in ground water samples collected simultaneously from the same spatial location during a forced-gradient test in the Borden aquifer using polytetrafluoroethene (PTFE) and stainless steel miniwells (1/8-inch O.D.). A semiautomated organic analytical system was used on-site to obtain real-time results, which avoided sample holding problems and permitted optimizing sampling times. The breakthrough curves (plots of concentration vs. time) for both organic compounds indicate that under the conditions of this experiment (low organic solute concentrations, short exposure time of sampling lines to the plume. adequate flushing of sampling lines) there is no significant difference between concentration histories (breakthrough curves) collected using a polytetrafluoroethene sampling line and those collected using a stainless steel sampling line. This suggests that organic solute tailing seen in this and also in a similar transport experiment previously conducted at the site is the result of transport processes in the aquifer rather than an artifact introduced by the PTFE miniwells.

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MINIMIZING CONTAMINATION HAZARDS TO WATERBIRDS USING AGRICULTURAL DRAINAGE EVAPORATION PONDS

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environmental MANAGEMENT 1991年第6期15卷 785-795页

作者： BRADFORD, DF SMITH, LA DREZNER, DS SHOEMAKER, JD Environmental Science and Engineering Program School of Public Health University of California Los Angeles USA

In much of the San Joaquin Valley, California, USA. inadequate drainage of applied irrigation water and accumulating salts in the soil have necessitated the installation of subsurface tile drainage systems to preserve crop productivity. At present, these subsurface drainage waters are disposed of by means of evaporation ponds or discharges into the San Joaquin River. Unfortunately, most of these agricultural drainage waters contain high concentrations of salts and naturally occurring trace elements, such as selenium, and recent evidence indicates that substantial numbers of waterbirds are exposed to contamination by selenium in the evaporation ponds. In order to avoid, minimize, or mitigate the adverse impacts on wildlife using the ponds, alternative pond management methods must be identified and evaluated for implementation. A number of methods have the potential to be cost-effective in significantly reducing the contamination hazard to birds using agricultural evaporation ponds. Twenty general methods were evaluated in this study, and four methods are recommended for implementation: remove levee vegetation. remove windbreaks, deepen the ponds, and haze birds. A number of other methods are recommended for further consideration because they appear to have good prospects for reducing the contamination hazard: steepen interior levee slopes, apply herbicides and insecticides, place netting on pond shorelines, and provide freshwater habitat adjacent to evaporation ponds. It may be necessary to use a combination of methods to effectively control selenium contamination of aquatic birds because it is unlikely that a single affordable pond management method will be able to entirely eliminate the contamination hazard.

关键词： AGRICULTURAL PONDS BIRDS EVAPORATION PONDS SELENIUM SELENIUM CONTAMINATION SHOREBIRDS SUBSURFACE DRAINAGE WATERFOWL

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FIELD SAMPLING OF RESIDUAL AVIATION GASOLINE IN SANDY SOIL

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GROUND WATER MONITORING AND REMEDIATION 1991年第2期11卷 107-120页

作者： OSTENDORF, DW LEACH, LE HINLEIN, ES XIE, YF David W. Ostendorf is an associate professor in the Environmental Engineering Program of the Civil Engineering Department at the University of Massachusetts (Civil Engineering Department University of Massachusetts Amherst MA 01003). His research interests include unconfined aquifer contamination hazardous waste site remediation and analytical modeling of problems in environmental fluid mechanics. Dr. Ostendorf is a registered professional engineer in Massachusetts and a member of the American Geophysical Union American Society of Civil Engineers Soil Science Society of America Water Pollution Control Federation and Association of Environmental Engineering Professors as well as the National Water Well Association. Lowell E. Leach is an environmental engineer with the Robert S. Kerr Environmental Research Laboratory of the U.S. Environmental Protection Agency (RS Kerr Environmental Research Laboratory U.S. EPA P.O. Box 1198 Ada OK74820). Leach received his B.S. ingeological engineering at the University of Oklahoma in 1959 and has been a registered professional engineer in Oklahoma since 1966. With 29 years of experience in field applications of geological engineering he is responsible for developing methodology for sampling ground water and subsurface materials for the Robert S. Kerr Environmental Research Laboratory. Erich S. Hinlein is a research assistant in the Environmental Engineering Program of the Civil Engineering Department at the University of Massachusetts (Civil Engineering Department University of Massachusetts Amherst MA 01003). His research interests include ground water pollution hazardous waste site investigation and transport processes in unconfined aquifers. Hinlein graduated with a B.S. in electrical and computer engineering from the University of Massachusetts at Amherst in May 1985 and entered the Environmental Engineering Master's Degree Program in January 1989. Yuefeng Xie is a postdoctoral research associate in the Environmental Engineering Program of the Civil Engine

Two complementary field sampling methods for the determination of residual aviation gasoline content in the contaminated capillary fringe of a fine, uniform, sandy soil were investigated. The first method featured field extrusion of core barrels into pint-size Mason jars, while the second consisted of laboratory partitioning of intact stainless steel core sleeves. The barrel extrusion procedure involved jar headspace sampling in a nitrogen-filled glove box, which delineated the 0.7m thick residually contaminated interval for subsequent core sleeve withdrawal from adjacent boreholes. Soil samples removed from the Mason jars (in the field) and sleeve segments (in the laboratory) were subjected to methylene chloride extraction and gas chromatographic analysis to compare their aviation gasoline content. The barrel extrusion sampling method yielded a vertical profile with 0.10m resolution over an essentially continuous 5.0m interval from the ground surface to the water table. The sleeve segment alternative yielded a more resolved 0.03m vertical profile over a shorter 0.8m interval through the capillary fringe. The two methods delivered precise estimates of the vertically integrated mass of aviation gasoline at a given horizontal location, and a consistent view of the vertical profile as well. In the latter regard, a 0.2m thick lens of maximum contamination was found in the center of the capillary fringe, where moisture filled all voids smaller than the mean pore size. The maximum peak was resolved by the core sleeve data, but was partially obscured by the barrel extrusion observations, so that replicate barrels or a half-pint Mason jar size should be considered for data supporting vertical transport analyses in the absence of sleeve partitions.

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ASSESSING AND MANAGING environmental RISK

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environmental PROGRESS 1991年第2期10卷 M2-M2页

作者： LOEHR, RC H. M. Alharthy Centennial Chair and Professor Environmental and Water Resources Engineering Program The University of Texas at Austin and Chairman Science Advisory Board U.S. Environmental Protection Agency

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A METHOD FOR ASSESSING RESIDUAL NAPL BASED ON ORGANIC-CHEMICAL CONCENTRATIONS IN SOIL SAMPLES

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GROUND WATER MONITORING AND REMEDIATION 1991年第2期11卷 128-136页

作者： FEENSTRA, S MACKAY, DM CHERRY, JA Stan Feenstra is a hydrogeochemist and president of Applied Groundwater Research Ltd. in Mississauga Ontario He received a B.Sc. in earth sciences and an M.Sc. in hydrogeology from the University of Waterloo in 1978 and 1980 respectively and was designated a Certified Ground Water Professional by AGWSE in 1989. Since 1980 he has been a ground water consultant with Golder Associates in Mississauga Ontario and Zenon Environmental in Burlington Ontario and founded Applied Groundwater Research Ltd. in 1987. Feenstra specializes in the hydrogeochemical evaluation of ground water contamination at waste disposal facilities and chemical spill sites. He is currently a Ph.D. candidate in hydrogeology and research associate in the Waterloo Centre for Ground Water Research at the University of Waterloo (Waterloo Ontario N2L 3G1) and is involved in research related to the behavior of dense organic solvents in ground water. Douglas M. Mackay is an adjunct professor at the Waterloo Centre for Groundwater Research at the University of Waterloo Waterloo Ontario (N2L3G1). Dr. Mackay received a B.S. in engineering and M.S. and Ph.D. in civil engineering from Stanford University in 1970 1973 and 1981 respectively. From 1986 to 1990 he was a faculty member of the Environmental Science and Engineering Program of the UCLA School of Public Health. His research focuses on field studies of transport and fate of organic chemicals in ground water various scale studies of decontamination of soil and ground water and ground water monitoring technologies. John A. Cherry is a professor at the Waterloo Centre for Groundwater Research at the University of Waterloo Waterloo Ontario (N2L 3G1). He received his B.S. in geological engineering from the University of Saskatchewan in 1962. He received his M.S. from the University of California at Berkeley in 1964 and his Ph.D. from the Department of Geology at the University of Illinois in 1966. His research interests include the field study and modeling of contaminants in ground wat

Ground water contamination by non-aqueous phase liquid (NAPL) chemicals is a serious concern at many industrial facilities and waste disposal sites. NAPL in the form of immobile residual contamination, or pools of mobile or potentially mobile NAPL, can represent continuing sources of ground water contamination. In order to develop rational and cost-effective plans for remediation of soil and ground water contamination at such sites, it is essential to determine if non-aqueous phase liquid (NAPL) chemicals are present in the subsurface and delineate the zones of NAPL contamination. The presence of NAPL pools may be evident as a floating or sinking phase in monitoring wells. The residual NAPL contamination may be identified in soil samples if residual contents are high and contaminated zones in the soil cores are thick. However, visual identification may not be effective if residual contents ar elow or if the NAPL residual is distributed heterogeneously in the samples. The chemical analysis of soil samples provides a measure of the total chemical concentration in the soil but cannot determine directly whether NAPL is present in the samples. Qualitatively, soil analyses that exhibit chemical concentrations in the percent range or > 10,000 mg/kg would generally be considered to indicate the presence of NAPL. However, the results of soil analyses are seldom used in a quantitative manner to assess the possible presence of residual NAPL contamination when chemical concentrations are lower and the presence of NAPL is not obvious. The assessment of the presence of NAPL in soil samples is possible using the results of chemical and physical analyses of the soil, and the fundamental principles of chemical partitioning in unsaturated or saturated soil. The method requires information on the soil of the type typically considered in ground water contamination studies and provides a simple tool for the investigators of chemical spill and waste disposal sites to assess whether soil

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BINATIONAL MANAGEMENT OF HAZARDOUS-WASTE - THE MAQUILADORA INDUSTRY AT THE UNITED-STATES MEXICO BORDER

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environmental MANAGEMENT 1990年第4期14卷 441-450页

作者： PERRY, DM SANCHEZ, R GLAZE, WH MAZARI, M Environmental Science and Engineering Program School of Public Health University of California Los Angeles USA

Foreign-owned industry in the form of assembly plants, termed maquiladora, has become very important in Mexico to the extent that it represents the second largest source of foreign exchange and is a valuable source for employment and regional development. The economic prosperity gained from the rapid growth of the maquiladora industry has been accomapanied by increased environmental and human health risks associated with generation of hazardous waste. Diversification of industry has resulted in the predomination of those sectors that likely use hazardous substances. The Mexicali-Calexico border region was selected to demonstrate the potential for environmental and health risks associated with the generation of hazardous waste. Estimates for the generation of hazardous waste were obtained from 34 maquiladora plants in Mexicali, represented by the electronic and electronic equipment and parts, mechanical and transportation equipment, and toys and sporting equipment sectors. Repeated detection of volatile organic compounds in the New River at the US-Mexico border suggests that hazardous waste from the printed circuit board industry in Mexicali is not being disposed of in a proper manner. Potential adverse health effects, such as carcinogenic and mutagenic responses associated with the detected volatiles, are discussed. US and Mexico national legislation and the Binational environmental Agreement were examined for their adequacy to ensure proper management of hazardous waste generated by the maquiladora industry. environmental policy options are presented that focus on: (1) increased environmental accountability of US parent companies for their maquiladora assembly plants in Mexico;and (2) more integration between US Customs and border states with the US environmental Protection Agency to improve the binational management of hazardous waste generated by the maquiladora industry.

关键词： environmental policy Hazardous waste Maquiladora industry US-Mexico border

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