bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identifying Potential Pollutant Point Sources in an Area of High Ground Water Consumption
Authors: Davis Ronnie McConnell , Flores Patricia Irene 
Published: February 2007

AbstractThe Commonwealth of Pennsylvania relies heavily upon its ground water resources for drinking water. The U.S. Environmental Protection Agency, Region III, is responsible for regulating the discharge of waste to the subsurface through injection wells within Pennsylvania. To facilitate identification of industrial facilities unregulated by EPA that may be contaminating ground water through industrial water and waste water discharge wells, a screening procedure was devised utilizing a Geographic Information System (GIS). This procedure involved cross‐referencing locations of industrial sites to maps of municipal sewer systems. The effectiveness of this GIS screening procedure was investigated in seven counties in southeastern Pennsylvania. Facilities identified by the procedure were inspected for possible violations of Underground Injection Control (UIC) program regulations. As a result of these inspections, many facilities were found to be illegally discharging waste into ground water. In addition, other EPA program violations were identified. The project demonstrated that the GIS screening procedure can be an effective tool to locate sources of pollution of ground water.
Statistical Modeling of Hydrogeologic Data ‐ Part I: Regression and ANOVA Models
Authors: Kufs Charles T. 
Published: February 2007

AbstractStatistical modeling can be a powerful tool for analyzing complex hydrogeologic and water quality data. The objectives of this paper are to discuss the nature of statistical models; to describe two types of statistical models, regression models, and analysis of variance (ANOVA) models; and to give examples of how the models have been and could be applied to solve hydrogeologic problems.
Suggested Modifications to Ground Water Sampling Procedures Based on Observations from the Colloidal Borescope
Authors: Kearl Peter M. , Korte Nic E. , Cronk Tom A. 
Published: February 2007

AbstractObservations of colloidal movement under natural conditions and during pumping were conducted at several field sites. Results indicate that several modifications to present sampling protocols may improve the representativeness and cost effectiveness of obtaining ground water samples for assessing the total mobile contaminant load. These modifications include the installation of dedicated sampling devices, limited purging of the well prior to sampling, sampling at a flow rate of 100 mL/min, and no filtering of samples. This sampling approach can result in significant cost savings while providing the best possible water samples.
A New Pumping Strategy for Petroleum Product Recovery from Contaminated Hydrogeologic Systems: Laboratory and Field Evaluations
Authors: Abdul Abdul S. 
Published: February 2007

AbstractMore than 200,000 gallons of automatic transmission fluid (ATF) leaked from an underground storage tank system and contaminated an area of about 64,000 ft2 of a soil and ground water system. A pumping strategy for improved drainage and recovery of free oil was developed, tested in a laboratory model aquifer, and implemented and evaluated at the field site. This pumping strategy differs from conventional approaches in two important ways: (1) The oil recovery rate is carefully controlled to maximize the pumping rate while maintaining continuity between the oil layer in the soil and the recovery well, to avoid isolation of the oil in the subsurface; and (2) The rate of ground water pumping is controlled to maintain the depressed oil/water interface at its prepumped position. This approach prevents further spread of oil into the ground water, prevents reduction in the volume of recoverable oil due to residual retention, and maintains a gradient for oil flow toward the recovery well. In a model aquifer study, nearly 100 percent of the recoverable volume of ATF was pumped from the system, and about 56,000 gallons of the ATF has been recovered from the field site.
A Diffusive Sampler for Passive Monitoring of Underground Storage Tanks
Authors: Karp Kenneth E. 
Published: February 2007

AbstractPassive measurements of volatile organic compounds (VOCs) provide a method for early detection and long‐term monitoring of potential leaks from underground storage tanks (USTs) and associated fuel service lines. A diffusive sampler was constructed of a sorbent tube that fits inside a specially designed sampling chamber. VOCs in the soil enter the chamber by molecular diffusion and are collected by the sorbent. The sorbent is easily retrieved for laboratory analyses by thermally desorbing into a gas chromatograph/mass spectrometer (GC/MS), or qualitative concentrations can be determined directly in the field with specific‐indicator detectors.The diffusive samplers were evaluated in an exposure chamber under controlled conditions. Laboratory measurements of the sorbed mass of organic vapor were found to be in close agreement with theoretical values and indicate the passive sampling approach is viable for detecting relatively low concentrations of organic vapors in the vadose zone over a one‐day sampling period, as well as providing relatively long‐term monitoring periods up to 58 days. A field test found the sampling approach successful in identifying an area where the vadose zone was contaminated by leaking petroleum USTs.
Field vs. Lab Alkalinity and pH: Effects on Ion Balance and Calcite Saturation Index
Authors: Shaver Robert B. 
Published: February 2007

AbstractGround water samples for a hydrochemical investigation were collected from 92 observation wells completed in a shallow, unconfined aquifer in southeastern North Dakota. The samples showed predominantly an increase in HCO3‐ (positive bias) and both a pH decrease (positive bias) and a pH increase (negative bias) from field to lab. Positive pH bias generally was associated with ground water characterized by dissolved‐solids concentrations less than 400 mg/L. Negative pH bias generally was associated with ground water characterized by dissolvedsolids concentrations greater than 400 mg/L.Observed HCO3‐ bias from field to lab slightly distorted ion balance distribution. Excess anions greater than 2 percent generally corresponded to increased HCO3‐ from field to lab.Observed HCO3‐ and pH bias significantly distorted the distribution of calcite saturation indices. Samples with dissolved‐solids concentrations less than 400 mg/L that generally showed a positive pH bias had a mean change in calcite saturation index of ‐0.214 (toward undersaturation). Samples with dissolved‐solids concentrations greater than 400 mg/L that generally showed a negative pH bias had a mean change in calcite saturation of +0.132 (toward over saturation).Calcite saturation indices were much more sensitive to observed pH bias than to observed HCO3‐ bias. Linear regression analysis indicates % percent of the variability in calcite saturation index change from field to lab is attributed to change in pH from field to lab. Field pH should be used to compute calcite saturation index.
Atrazine in a Stream‐Aquifer System: Transport of Atrazine and Its Environmental Impact Near Ashland, Nebraska
Authors: Blum Darryl A. , Carr James D. , Davis Ralph K. , Pederson Darryll T. 
Published: February 2007

AbstractLincoln's municipal wellfield consists of 44 wells located adjacent to the Platte River near Ashland, Nebraska. The herbicide atrazine was monitored in the river and two transects of monitoring, wells. The amount of atrazine transported down the Platte River in 1989, 1990, and 1991 was shown to increase each year. Induced recharge from the Platte River results in movement of atrazine from the river into the aquifer. A 21‐day lag time was determined for the movement of atrazine from the river to a transect of monitoring wells 10 feet West of the bank. The role that colloids play on the transport of atrazine was determined to be insignificant. A small percentage of atrazine found in the river was determined to come from rain water. The infiltration of agrichemical‐contaminated river water was shown to significantly reduce the quality of raw water and finished water being produced by the adjacent aquifer.
Atrazine in a Stream‐Aquifer System: Estimation of Aquifer Properties from Atrazine Concentration Profiles
Authors: Davis Ralph K. , Pederson Darryll T. , Blum Darryl A. , Carr James D. 
Published: February 2007

AbstractLincolns municipal wellfield consists of 44 wells developed in an alluvial aquifer adjacent to the Platte River near Ashland, Nebraska Induced recharge from the river is the primary source of water for the wellfield. Wafer samples were collected on a periodic basis from the Platte River arid two transects of monitoring wells. These samples were analyzed for the herbicide atrazine, which was used as a tracer of induced recharge in this stream‐aquifer system. Atrazine concentrations in the river and aquifer were much less than 1.0 ppb during late fall and winter, but increased to as high as 18.9 ppb during spring and summer, associated with runoff from upgradient agricultural lands. There was approximately a 21‐day lag time from the first detection of increasing atrazine concentration in the river to the first detection in monitoring wells immediately adjacent to the river. This lag time was relatively constant throughout the year and from one year to the next, even with major fluctuations of river stage and wellfield production. This consistency of lag time indicated that the travel times from the river to the first set of monitoring wells immediately adjacent to the river were fairly constant.Paths of preferential flow were identified in the aquifer at a depth of 25 to 35 feet below land surface. This aquifer zone appeared to play a significant role in movement of water from beneath the river into the wellfield.Aquifer dispersivity was calculated using a method described by Hoehn and Santschi (1987). Macrodispersivity (AL) was shown to increase linearly over the scale of the wellfield. Calculated values of AL were within limits of other reported values for this type of aquifer material and agreed well with values reported by Hoehn and Santschi (1987); These findings will be extremely beneficial for planning and management of the municipal wellfield.
The Resonant Sonic Drilling Method: An Innovative Technology for Environmental Restoration Programs
Authors: Barrow Jeffrey C. 
Published: February 2007

AbstractThe resonant sonic drilling method offers unique capabilities to the environmental restoration market. By using a drill head that imparts high‐frequency, high‐force vibrations into a steel drill pipe, continuous, relatively undisturbed cores can be taken through virtually any formation. The resonant sonic method requires no mud, air, water, or other circulating medium for penetration: drills very fast; easily drills at any angle through formations such as rock, clay, sand, boulders, permafrost, or glacial till; and yields no cuttings in the drilling process. Case histories of projects using the method demonstrate excellent results but also indicate several problem areas with the method in its present state. Expanding research efforts to further develop the resonant sonic drilling method should help solve current drawbacks, and could produce a drilling technology for environmental work that significantly changes the way monitoring wells are drilled and constructed.
Leaching Potential of Turf Care Pesticides: A Case Study of Long Island Golf Courses
Authors: Primi Patricia , Surgan Michael H. , Urban Timothy 
Published: February 2007

AbstractPesticides used to maintain golf course turf can threaten ground water. This concern is particularly important in most of New York's Long Island, where generally sandy soils overlie a sole source aquifer. This study uses two methods to evaluate the potential for pesticides that are commonly used on Long Island's golf courses to leach to ground water.Adapting the Pesticide Root Zone Model (PRZM). Release 1. for dense turf and applying site‐specific soil data, certain pesticides, including metalaxyl and trichlorfon, are identified as potential problem leachers. PRZM simulations also identify the Long Island soils, including the sandy Plymouth and Carver soils, which arc most vulnerable to leaching.When adequate input data for PRZM is unavailable, the ground water ubiquity score (GUS) method may be useful. GUS teachability classifications of pesticides commonly applied on Long Island golf courses, and of pesticides actually detected in ground water samples taken on Long Island, agree with PRZM predictions and the field data. The GUS method is applied to the evaluation of the leaching potential of pesticide degradation products (DCPA, maneb, and mancozeb metabolites), and the degradation products are shown to be a greater threat to ground water than their parent compounds.These methods are potentially useful in designing ground water monitoring programs and for guiding the pesticide use and selection decisions of golf course managers.
Ground Water Monitoring Statistics Update: Part II: Nonparametric Prediction Limits
Authors: Davis Charles B. , McNichols Roger J. 
Published: February 2007

AbstractNonparametric prediction limits can be useful statistical tools for ground water monitoring at facilities regulated under RCRA Subtitle C. Subtitle D. and similar regulations. New, exact tables arc presented for both “1 of m” plans (m chances to gel one observation inbounds at each of r monitoring wells to avoid a statistically significant increase) and “California” plans (first or all of the next m‐1 observations inbounds at each well). The tables provide per‐constituent significance levels (false positive rates) as a function of the background sample size n. m. r, the prediction limit (the largest or the next to largest, background observation), and the confirmatory resampling plan selected.When used in a monitoring program, future observations from several wells are compared with a prediction limit obtained from a common background sample. The table significance levels therefore depend critically on having IID (independent and identically distributed) observations. In particular, the false positive rate computations are not valid, and the procedures should not be used, with constituents whose measurements exhibit inherent spatial or systematic temporal variability.Recent U.S. EPA guidance explicitly encourages controlling facility‐wide false positive rates over both constituents and wells. Nonparametric prediction limits, particularly with California resampling plans, will have greater difficulty in meeting the new. lower per‐constituent false positive rate goals than previous ones, especially if many constituents are involved. Nonetheless, nonparametric prediction limits remain superior to other commonly used procedures for dealing with data with high proportions of nondctects.
A Risk‐Based Approach for Managing Hazardous Waste
Authors: Chiang C.Y. , Petkovsky P.D. , McAllister P.M. 
Published: February 2007

AbstractIn 1992, the U.S. Environmental Protection Agency (EPA) proposed risk‐based management of hazardous waste. A major component of the proposed rule is the determination of non‐site‐ specific screening concentration levels from waste leachate. Ground water at a downgradient exposure point must not exceed those screening levels, or more stringent requirements would apply.The screening concentration level is determined with verified models and equations that simulate the transport and attenuation of chemicals as they travel from the source area to the exposure point. A consortium of screening levels is determined in this paper by considering varying physical, chemical, and biological conditions. In addition, a method is developed for multi component leaching from contaminated soils in a landfill to determine the time‐dependent behavior of a finite source. Finally, this paper discusses infiltration rate through the clay liner.
A Field Study of Enhanced Recovery of DNAPL Pooled Below the Water Table
Authors: Michalski Andrew , Metlitz Michael N. , Whitman Ira L. 
Published: February 2007

AbstractA large subsurface pool of waste solvent product, consisting primarily of 1,1,1‐tichloroethanc and carbon tetrachloride, was encountered during investigations at an industrial site in northern New Jersey. In the 1950s the product was discharged through a settling chamber directly below the shallow water table. Eventually the product accumulated within elongated depressions of erosional surface of varved clays at depths 10 to 15 feet below grade. The host sediment, line to medium sand, was overlain by line sand and silt. The delineated area of pooled DNAPLs covered 2750 feet2, and the maximum pool thickness exceeded 3 feel.The primary recovery involved pumping product from nine wells. Each recovery well was equipped with a sump extending into the clay, which enabled the system to keep the product pumping level below the bottom of the pool. A total of 3495 gallons of solvent product was recovered over two years. Nearly half of this volume was produced by two wells placed at the lowest points of the pools. Postpumping sampling of the former pools indicated that 43 to 94 percent of the pooled solvent mass was removed during the primary recovery. Average initial product salutation within the pool was estimated at 53.2 percent of the total porosity measured at 31 percent. Average residual saturation after the primary product recovery was 3.7 percent of the total pore volume.To test the feasibility of residual product recovery, an experimental secondary recovery was undertaken. Using sheet piling, a 506 feet2 lest cell was constructed inside the former DNAPL pool. The cell featured a central recovery well, six peripheral wells, and monitoring probes. I he selected sequence of secondary operations included partial dewatering. hot water injection, final dewatering, and thermally enhanced vapor extraction (TVE). During six weeks of the secondary recovery operations. 87.9 gallons of product were removed, of which 72 percent was from TVE. 25 percent from hydraulic mobilization effects. and 3 percent from dissolution of residuals. Confirmatory soil sampling showed an average reduction of residual contamination by 93.4 percent in comparison to the concentration of residuals prior to the secondary recovery. For the lest cell, a combined total solvent recovery of 99.6 percent was achieved. This high recovery exceeded DNAPL recoveries expected or achieved in other field‐scale attempts.
Low‐Flow Purging and Sampling of Ground Water Monitoring Wells with Dedicated Systems
Authors: Puls Robert W. , Paul Cynthia J. 
Published: February 2007

AbstractA field study was conducted to assess purging requirements for dedicated sampling systems in conventional monitoring wells and for pumps encased in short screens and buried within a shallow sandy aquifer. Low‐flow purging methods were used, and wells were purged until water quality indicator parameters (dissolved oxygen, specific conductance, turbidity) and contaminant concentrations (chromate, trichloroethylene, dichloroethylene) reached equilibrium. Eight wells, varying in depth from 4.6 to 15.2 m below ground surface, were studied. The data show that purge volumes were independent of well depth or casing volumes. Contaminant concentrations equilibrated with less than 7.5 I. of purge volume in all wells. Initial contaminant concentration values were generally within 20 percent of final values. Water quality parameters equilibrated in less than 10 L in all wells and were conservative measures for indicating the presence of adjacent formation water. Water quality parameters equilibrated faster in dedicated sampling systems than in portable systems and initial turbidity levels were lower.
The Occurrence of Agricultural Chemicals in Illinois' Rural Private Wells: Results from the Pilot Study
Authors: Mehnert E. , Schock S.C. , Earnhardt M.L. , Caughey M.E. , Chou S.F.J. , Dey W.S. , Dreher G.B. , Ray C. 
Published: February 2007

AbstractWater samples from 240 private wells in rural Illinois were collected over one year and analyzed for 39 agricultural chemicals. Sampling was conducted to provide preliminary information to refine a plan for a statewide survey of the agricultural chemical contamination of rural private wells. Wells were sampled according to a stratified random sampling plan that included four classes of depth lo the uppermost aquifer material and two classes of well type. Depth lo uppermost aquifer material was defined as the depth from ground surface to a geologic material that, if saturated, could he used as an aquifer.Occurrence, defined as the presence of one or more target analytes in a well water sample above some specified concentration, was shown to be higher in large‐diameter bored or dug wells than in small‐diameter drilled wells. For small‐diameter wells, occurrence generally decreased as the depth to the uppermost aquifer material increased, In addition, depth to the uppermost aquifer material could be used to predict the occurrence of some individual agricultural chemicals, such as nitrate and atrazine, but could not be used to predict the occurrence of pielorarn or pesticides in small‐diameter wells.Of the 39 target analytes, 10 were detected at concentrations exceeding their respective minimum reporting levels. Nitrate and atrazine were the only compounds found at concentrations exceeding their respective maximum contaminant levels (MCLs) or U.S. EPA lifetime health advisory limits (HAI.s).A nonparametric statistical technique, contingency table analysis, identified factors associated with the occurrence of agricultural chemicals in three of the file study areas. Elevated specific conductance (>500 μmhos/cm) of the sampled water was strongly associated with the occurrence of agricultural chemicals. This association was common to all three study areas analyzed. Identification of the source of the specific conductance could help identify the dominant pathway for transport of agricultural chemicals to ground water.
Organic Acid Derivatization Techniques Applied to Petroleum Hydrocarbon Transformations in Subsurface Environments
Authors: Barcelona Michael J. , Lu Jie , Tomczak Daniel M. 
Published: February 2007

AbstractEvidence for the natural microbial remediation of subsurface fuel contamination situations should include identification and analysis of transformation or degradation products. In this way. u mass balance between fuel constituents and end products may be approached to monitor cleanup progress. Application of advanced organic acid metabolite derivatization techniques to several known sites of organic compounds and fuel mixture contamination provide valuable information on the pathways and progress of microbial transformation. Good correlation between observed metabolites and transformation pathways of aromatic fuel constituents were observed at the sites.