bluuebunny/crossref_metadata_2025 huggingface dataset:
Seizure‐Promoting Effect of Blood–Brain Barrier Disruption
Authors: Marchi Nicola , Angelov Lilyana , Masaryk Thomas , Fazio Vincent , Granata Tiziana , Hernandez Nadia , Hallene Kerri , Diglaw Tammy , Franic Linda , Najm Imad , Janigro Damir
Published: February 2007

Summary: Purpose:It is generally accepted that blood–brain barrier (BBB) failure occurs as a result of CNS diseases, including epilepsy. However, evidences also suggest that BBB failure may be an etiological factor contributing to the development of seizures.

Methods:We monitored the onset of seizures in patients undergoing osmotic disruption of BBB (BBBD) followed by intraarterial chemotherapy (IAC) to treat primary brain lymphomas. Procedures were performed under barbiturate anesthesia. The effect of osmotic BBBD was also evaluated in naive pigs.

Results:Focal motor seizures occurred immediately after BBBD in 25% of procedures and originated contralateral to the hemisphere of BBBD. No seizures were observed when BBB was not breached and only IAC was administered. The only predictors of seizures were positive indices of BBBD, namely elevation of serum S100β levels and computed tomography (CT) scans. In a porcine model of BBBD, identical procedures generated an identical result, and sudden behavioral and electrographic (EEG) seizures correlated with successful BBB disruption. The contribution of tumor or chemotherapy to acute seizures was therefore excluded.

Conclusion:This is the first study to correlate extent of acute BBB openings and development of seizures in humans and in a large animal model of BBB opening. Acute vascular failure is sufficient to cause seizures in the absence of CNS pathologies or chemotherapy.
Safety of Rapid Intravenous Loading of Valproate
Authors: Limdi Nita A. , Knowlton Robert K. , Cofield Stacey S. , Ver Hoef Lawrence W. , Paige Alfred L. , Dutta Sandeep , Faught Edward
Published: February 2007

Summary:  Background: The introduction of IV valproic acid (VPA) has facilitated its use in situations where oral administration is not feasible. The present study was designed to evaluate the safety of administration of undiluted VPA (20 or 30 mg/kg/min) administered intravenously at rates of 6 or 10 mg/kg/min.

Methods: Forty patients received a VPA loading dose (20 or 30 mg/kg) at 6 or 10 mg/kg/min. Heart rate (HR), mean arterial pressure (MAP), oxygen saturation, respiratory rate, and three lead ECG measurements were taken at baseline. Following dose administration the measurements were repeated at 2.5‐min intervals for the first 20 min, then at 30, 45, 60 min, and 4 h. Local tolerance was defined as absence of irritation or phlebitis at the site of injection. Systemic tolerability was defined as absence of significant changes in vital signs and level of consciousness (LOC). Changes in vital signs and local intolerance scores were compared across time using repeated measures analysis of variance.

Results: Rapid administration was well tolerated with no significant changes in HR (p = 0.9) or MAP (p = 0.7). Complaints of local irritation were transient, lasting less than 3 min in all patients with no indication of redness, irritation, or phlebitis. No patient exhibited a decline in the LOC.

Conclusions: Rapid administration of undiluted valproate is safe and well tolerated at infusion rate up to 10 mg/kg/min and doses of up to 30 mg/kg. The lack of serious cardiovascular, neurological, hepatic, or local adverse effects supports the use of VPA in emergent situations.
Children, Coping, and the Stress of Illness: A Synthesis of the Research
Authors: Ryan‐Wenger Nancy A.
Published: February 2007

purpose. To synthesize and critique the current research on coping strategies used by children who are ill, to identify gaps in the research base, and to provide direction for practice, future research, and theory development

population. 32 research articles on coping strategies used by children with chronic or acute illness

conclusions. Children's repertoire of coping strategies is the same during health and illness, although the frequency or effectiveness of some of the strategies is often different.

practice implications. Much more in‐depth descriptive and longitudinal research is needed, particularly how, when, and why coping strategies are learned, retained, and later discarded. Research is needed to examine the relationship between coping and health outcomes, and on the effectiveness of nursing interventions designed to influence children's coping behavior.
Use of a Projective Technique to Assess Young Children's Appraisal and Coping Responses to a Venipuncture
Authors: Caty Suzanne , Ellerton Mary Lou , Ritchie Judith Anne
Published: February 2007

purpose. To examine the appraisal, emotional and coping responses of young hospitalized children to three phases of a venipuncture procedure.

design. Exploratory, descriptive

setting. Pediatric unit of a community hospital

participants. Four‐ to 9‐year‐old hospitalized children (N = 45)

main outcome measures. Data were obtained by means of a projective technique and interview format. Content analysis of the children's responses was guided by the use of four published measures (appraisal, behavioral coping strategies, cognitive coping strategies, and helpful interventions).

results. The children appraised each phase of the venipuncture as a threat, a benefit, or a threat/benefit. The most frequently identified behavioral coping strategies were self‐protective behaviors and returning to normal activities. The most frequently identified cognitive coping behaviors were reality‐oriented working through, emotion‐regulating cognitions, and diversionary thinking. The children reported the most helpful intervention as providing information about the event.

conclusion. The children were able, through a projective technique, to appraise a venipuncture and spontaneously identify many cognitive and behavioral coping strategies and interventions to help them manage a venipuncture.
Outcomes of a Nursing Intervention for Siblings of Chronically Ill Children: A Pilot Study
Authors: Williams Phoebe Dauz , Hanson Sandra , Karlin Robyn , Ridder Lavonne , Liebergen Adrienne , Olson Joyce , Barnard Martha U. , Tobin‐Rommelhart Susan
Published: February 2007

purpose. To evaluate the outcomes of a structured, educational, and support group intervention (ISEE, Intervention for Siblings: Experience Enhancement) for siblings of children with chronic illness (cancer, cystic fibrosis, diabetes, and spina bifida), including a session with parents about sibling needs; and to describe sibling and parent perceptions of sibling experiences at home.

design. One‐group, pretest‐posttest pilot study

participants. A convenience sample of 22 siblings and parents

setting. A Midwestern university medical center

main outcome measures. Knowledge of Illness Test, parent ratings on a global, single item, 10‐point scale

results. Sibling test scores increased significantly after the intervention, compared to baseline. Parents' average evaluation rating was 9 on a 10‐point scale. Parents supported their positive ratings with verbatim descriptors. Sibling and parent perceptions of sibling experiences were congruent, suggesting the sources of potential adjustment problems in siblings, and were consistent with the literature.

conclusions. A randomized, clinical trial with a larger sample size is needed to evaluate the intervention further.
Learning the Baby: A Maternal Thinking and Problem‐Solving Process
Authors: Sullivan Joan M.
Published: February 2007

purpose. To describe a maternal problem‐solving process from new mothers' day‐to‐day experience of caring for and developing a relationship with their babies

design. Qualitative study using grounded theory approach

setting. Mothers' homes (n = 23) and workplaces (n = 2)

participants. 25 mothers of babies from 2 weeks to 7 months

main outcome measures. Semi‐structured interviews

results. “Learning the Baby” was a major thinking process that emerged. Systematic thinking dominated mothers' problem‐solving. Even after the babies were comforted, mothers were not certain their efforts alleviated the babies' problems, because they usually were not certain of the problem.

conclusions. Mothers' thinking directs their caregiving actions. The findings were related to previous problem‐solving and women's thinking perspectives. Nurses must use planned and unplanned encounters effectively to collaborate with and teach mothers about baby behavior and health care.
Genetic Testing for Fragile X
Authors: Prows Cynthia A. , Lovell Anne M. , Froese‐Fretz Ann
Published: February 2007

Ask the Expert provides research‐based answers to practice questions submitted by JSPN readers. Where possible, evidence from research is used to support the experts' recommendations.
Conflicting Responses: The Experiences of Fathers of Infants Diagnosed With Severe Congenital Heart Disease
Authors: Clark Suzanne M. , Miles Margaret Shandor
Published: February 2007

purpose. To explore the experiences of fathers of infants newly diagnosed with severe congenital heart disease.

design. An analysis of qualitative data collected as part of a larger longitudinal study of parenting the medically fragile infant.

participants. Eight fathers whose infants were hospitalized for severe congenital heart disease, were technology dependent at time of enrollment, and were expected to have serious chronic health problems at discharge.

data collection measures. Semistructured interviews in the hospital and the home until the child reached 15 months adjusted age.

results. Findings indicate that fathers experience four interrelated conflicting reactions: the joy of seeing the child born and becoming a father, plus the sadness and loss associated with the baby's illness; the challenge of becoming attached while dealing with fears about the infant's vulnerability and potential death; the need to try to maintain control while feeling a loss of control; and the struggle to remain strong for others while hiding their intense emotions. These findings extend the previous limited research about fathers by identifying the unique conflicts fathers of seriously ill infants experience in coping with the child's diagnosis and treatment. Findings have implications for intervening with fathers during the early diagnostic phase of a serious illness, particularly serious congenital heart disease.
Broken Past, Fragile Future: Personal Stories of High‐Risk Adolescent Mothers
Authors: Williams Christine , Vines Susan W.
Published: February 2007

purpose. To uncover what adolescent mothers view as their childhood struggles, their transition to the role of motherhood following a childhood of abuse/neglect, and their important relationships after they became parents.

design. Qualitative, phenomenological.

setting. Community‐based parenting program for first‐time mothers at risk for abusing or neglecting their children.

participants. Seven first‐time mothers, ages 13 to 20, who reported they had been abused and/or neglected as children. All had healthy newborns.

results. Five themes emerged from the data: impoverished past, disintegration of relationships, emotional distance, problem fixing, and reconnecting. Participants described a process of using the experience of pregnancy and parenting as a mechanism for growth. Becoming a parent provided an opportunity to receive support from family members and to build more positive relationships. They viewed the experience as a second chance for a successful and fulfilling life.
Using Parents' Concerns to Detect and Address Developmental and Behavioral Problems
Authors: Glascoe Frances Page
Published: February 2007

purpose. Half of all children with disabilities are not identified before school entrance, precluding their participation in early intervention programs with known value in reducing high school dropout rates, increasing employment, delaying child‐bearing, and reducing criminal behavior. Screening tests that can greatly improve detection rates have not been popular in primary care. This article describes an alternative approach in an evidence‐based technique relying on professional elicitation and interpretation of parents' concerns.

population. 971 children from pediatric practices, day‐care centers, public schools, and their siblings.

conclusions. Research shows that parents' concerns are as accurate as quality screening tests and that parents are equally able to raise important concerns regardless of differences in education and child‐rearing experience. Parents' concerns can be elicited quickly, and 92% of parents can answer questions in writing while in exam or waiting rooms. Parents' concerns can help make a range of other important decisions about children's developmental and behavioral needs.
Improving Access to Health Care for Children
Authors: Sochalski Julie , Villarruel Antonia M.
Published: February 2007

issues and purpose. The number of uninsured children has been growing at an alarming rate. The most vulnerable children are those in lower‐income families who are falling through the cracks between evolving government‐sponsored health insurance programs. Recent policy initiatives may not be adequate to extend coverage to more children.

conclusions. Many low‐income children actually are eligible for Medicaid but are not enrolled for a variety of reasons. The numbers of these children have risen due to welfare reform. Better outreach efforts are needed to ensure that new child health insurance programs and Medicaid expansions achieve their goals.

implications for practice. A comprehensive assessment of insurance status and referral to community agencies should be an integral part of patient care for all healthcare providers.
Agenda for Children and Youth: Linking Research, Policy, and Practice
Authors: Montoya Patricia
Published: February 2007

issues and purpose. In this past century, we have made significant strides in our understanding of children's needs, but there is still much to learn as we enter the coming century. We must seek this new knowledge not only for the sake of knowing, but also for the sake of making change, ensuring that what we learn helps improve the future for our children and youth. These efforts require a strong link between policy, practice, and research.

conclusions. Research partnerships can build our base of knowledge and help answer emerging policy and practice questions. Through research that focuses on the diversity and developmental phases of children, we can bring policy and practice into line with an increasingly refined understanding of children and their needs.

practice implications. Because nurses look at the holistic needs of individuals, it is critical that they are involved in setting the social service research agenda and seeking ways that policy and practice can both inform and be informed by this research.
Talking with Teens: Successfully Screening for High‐Risk Behavior
Authors: Beall Sherrod , Froese‐Fretz Ann
Published: February 2007

Ask the Expert provides research‐based answers to practice questions submitted by JSPN readers.
Linking Practice With Research: The Role of the Unit Research Coordinator
Authors: Kotzer Anne Marie , Curley Martha
Published: February 2007

Scientific Inquiry provides a forum to facilitate the ongoing process of questioning and evaluating practice, presents informed practice based on available data, and innovates new practices through research and experimental learning.
“Love Is All You Need”? Student Nurses' Interest in Working With Children
Authors: Happell Brenda M.
Published: February 2007

ISSUES AND PURPOSE. To investigate the impact of comprehensive nursing education on the future career interests of undergraduate nursing students, with particular emphasis on attitudes toward working with children.

DESIGN AND METHODS. Descriptive design with surveys of 793 undergraduates in university schools of nursing throughout Victoria, Australia.

RESULTS. Working with children is the most popular of nine possible career choices. Student explanations reflected a love of, and desire to work with, children, suggesting a relatively naive and uninformed view.

PRACTICE IMPLICATIONS. In view of the problems experienced in the recruitment and retention of adequate numbers of pediatric nurses, there is an urgent need to promote a more realistic view of this area of practice.
Bone Loss in Adolescents Using Depo‐Provera
Authors: Kass‐Wolff Jane H.
Published: February 2007

ISSUES AND PURPOSE. Contraceptive methods that decrease bone density in a population already deficient in calcium are a rising concern in women's health.

CONCLUSIONS. Use of Depo‐Provera (DMPA) significantly decreases bone mass density (BMD) in normal adolescents up to the age of 21. DMPA is often used in adolescents with disabilities who may already be at high risk for osteoporosis. The effects are likely to be similar to that in ablebodied adolescents, but research is limited.

PRACTICE IMPLICATIONS. Through early identification of risk factors in able‐bodied and disabled adolescents, primary care providers considering the use of DMPA in adolescents can optimize BMD by providing adequate nutritional assessment, counseling on nutritional sources of calcium, calcium supplementation, guidance on exercise, and alcohol and smoking prevention or cessation.
Child Safety Seats Work!
Authors: McCue Mary , Villarruel Antonia
Published: February 2007

Scientific Inquiry provides a forum to facilitate the ongoing process of questioning and evaluating practice, presents informed practice based on available data, and innovates new practices through research and experimental learning.
Nursing Judgment: The Key to Pain Assessment in Critically III Children
Authors: Foster Roxie L. , Froese‐Fretz Ann
Published: February 2007

Ask the Expert provides answers to clinical questions for nurses in practice settings. Where possible, evidence from research is used to support the experts' recommendations.
Vaccine Safety Communication: The Role of the Pediatric Nurse
Authors: Stinchfield Patricia Kenefick , Froese‐Fretz Ann
Published: February 2007

Ask the Expert provides research‐based answers to practice questions submitted by JSPN readers.
Rearing the Child Who Is Technology Dependent: Perceptions of Parents and Home Care Nurses
Authors: O'Brien Maureen E. , Wegner Carole B.
Published: February 2007

ISSUES AND PURPOSE. Most children who are dependent on technology for survival live with their families at home. This study explores the perceptions of parents and home care nurses regarding rearing the technology‐dependent child.

DESIGN AND METHODS. In this qualitative study, interviews were conducted with 16 parents whose child is technology dependent and 15 registered nurses who provided home care.

RESULTS. Rearing the child who is technology dependent is similar to but different from raising other children. Parental communication and negotiation of child‐rearing expectations with home care nurses is essential.

PRACTICE IMPLICATIONS. Improved collaboration and communication between parents and nurses may reduce parental stress and enhance development for children who are dependent on technology.
How to Help Children and Adolescents Deal With the Threat of Terrorism
Authors: Hanze Douglas , Kuntz Kathleen Ryan
Published: February 2007

Collaborative Practice provides a forum for healthcare professionals to share expertise and enhance communication.
The Effects of Infant Feeding Decisions on Infant Growth
Authors: Barton Sharon Jackson , Howard Patricia Kunz , Rayens Mary Kay
Published: February 2007

ISSUES AND PURPOSE. To determine the effects of feeding decisions on infant growth in the first 6 months of life.

DESIGN AND METHODS. Growth measurements were collected twice during the first 6 months of infancy as part of a larger investigation of infant feeding practices (N = 52).

RESULTS. Infants who received solid foods before the age of 4 to 6 months weighed less than those who received solid foods after 4 to 6 months. There were no differences in growth measurements between formula‐fed and breastfed infants, although breast‐fed infants weighed more at birth.

PRACTICE IMPLICATIONS. Emphasize the importance of feeding breast milk (preferably) or formula only for the first 6 months. Advise parents to withhold fruit juices until the infant is at least 6 months old.
Balancing High‐Tech Nursing With Holistic Healing
Authors: Ward Susan L. , McDowell Betsy M.
Published: February 2007

Ask the Expert Provides research‐based answers to practice questions submitted by JSPN readers.
Selecting an Accurate Point‐of‐Care Testing System: Clinical and Technical Issues and Implications in Neonatal Blood Glucose Monitoring
Authors: Sirkin Amy , Jalloh Tina , Lee Luisa
Published: February 2007

issues and purpose.
Rapid identification and treatment of glucose abnormalities is crucial in the prevention of potentially devastating neurological injury in neonates. Choice of a point‐of‐care glucose testing system must consider accuracy, clinical advantages, and data management capabilities.

conclusions.
The benefits and limitations of point‐of‐care testing must be weighed against the time delay of central laboratory testing.

practice implications.
Considerations in selecting a point‐of‐care blood glucose monitoring system include accuracy, precision, versatility, and the potential for cross infection and blood loss. When a system is selected, studies must be done to identify potential sources of error and confirm the utility and accuracy of the system in the identified population.
Lucky Girls: Unintentional Avoidance of Adolescent Pregnancy Among Low‐Income African‐American Females
Authors: Martyn Kristy K. , Hutchinson Sally A. , Martin Jacquelyn H.
Published: February 2007

PURPOSE. To describe lucky adolescents who unintentionally avoid pregnancy.

DESIGN AND METHODS. The second phase of a descriptive qualitative study in which 17 low‐income African‐American females ages 19 to 26 participated in open‐ended interviews on how they avoided pregnancy as adolescents.

RESULTS. Constant comparative analysis revealed that five of the girls avoided pregnancy because they were “lucky“ that others insisted they use contraceptives. These lucky girls were unaware of sexual risks, but used contraceptives because they complied with decisions made by their parents, grandparents, and partners.

PRACTICE IMPLICATIONS. Lucky girls are at risk for adolescent pregnancy because they abdicate decision making to others and are likely to be overlooked in practice because they are using contraceptives. Promoting self‐protection includes assessment, knowledge, skills‐building strategies, and health‐promoting contracts between the nurse and adolescent.
The Application of Combined Seismic and Electrical Measurements to the Determination of the Hydraulic Conductivity of a Lake Bed
Authors: Taylor Robert W. , Cherkauer Douglas S.
Published: February 2007

The hydraulic properties of lake beds control the interactions between lakes and ground water systems, but these properties are normally difficult to measure directly. The authors’method combines seismic reflection and electrical measurements to map the relative hydraulic conductivity of lake bed sediments. A shipboard seismic profiling system provides sediment thickness, while a towed electrical array yields longitudinal conductance and electrical chargeability. The sediment's leakance (hydraulic conductivity/thickness) can be calculated from the longitudinal conductance data. Leakance may then be converted to relative hydraulic conductivity through the seismically derived sediment thicknesses. Simultaneously acquired electrical chargeability provides an independent measure of clay content. The seismic and electrical systems are computer automated and yield production rates of approximately five line‐kilometers/hour or 300 electrical soundings/hour. The systems provide continuous hydraulic information along the ship track rather than the point information derived from coring.

The procedure and systems have been used to map the bed of Lake Michigan offshore from an area of heavy pumpage. This location has been chosen to test the method because lake water has intruded the aquifer in plumes largely controlled by lake bed hydraulics. Mapping these plumes onshore permits the inference of the spatial distribution of offshore hydraulic conductivities. Offshore seepage measurements and numerical, chemical transport modeling of this site have confirmed the reliability of the geophysically derived hydraulic conductivities and have also demonstrated the improvement in numerical results achieved through the availability of spatially determined hydraulic conductivities.
A State‐Of‐The‐Art Approach to Hydrologic Data Management
Authors: Way S.C. , Wainwright H.K. , Ward W.P.
Published: February 2007

High‐accuracy electronic data acquisition equipment, a solid‐state memory, computer interface and software have been developed to provide a complete system for measuring and recording water level changes.

A small, stand‐alone hydrologic instrument (SE1000) provides the automation and accuracy of solid‐state electronics in pump tests, slug tests, and long‐ and short‐term ground water monitoring. The unit is powered by a high‐performance battery pack with a minimum life of four years. This instrument can be buried at the monitoring site for protection from vandals, animals and temperature extremes. Ten pre‐programmed 949‐point data schedules are standard. One schedule is logarithmic with an initial data interval of 0.2 seconds. Nine linear schedules provide data intervals ranging from 15 minutes to 1.5 days and corresponding test durations ranging from 10 days to 46 months. The stored data can be recovered directly via the LCD display or transferred to a computer. Software provides automatic data reduction with hard copy tables and plots.

This instrument has been used successfully in various locations in the United States.
Environmental Analysis of Iron‐Precipitating Bacteria in Ground Water and Wells
Authors: Smith Stuart A. , Tuovinen Olli H.
Published: February 2007

Iron‐precipitating bacteria are frequently cited as being involved in economically serious well and aquifer degradation that may also have a public health impact. Quantifying the populations of the iron‐precipitating bacteria present in ground water is a complex problem not yet resolved. A survey of historical and modern environmental literature provides numerous descriptions of iron bacteria in aquifers and wells, along with physicochemical data collected during bacterial sampling. These data are not conclusively linked with iron bacteria occurrence. Iron bacteria is a concept encompassing many genera and species of bacteria with varying morphology and physiology. Methods to detect bacteria and to quantify bacterial biomass in aquifers are being developed, but representative sampling remains a problem. Predictive analysis of iron bacterial growth awaits additional physiological and sampling research.
Geophysical Techniques to Delineate Saturated Alluvial Zones for the Siting of HVDC Power Transmission Return Electrodes
Authors: Hennon Kerry
Published: February 2007

As high‐voltage, direct‐current (HVDC) electrical power transmission technology advances, the siting and design of the grounded return electrodes become critical factors. Electrode sites should be chosen where surrounding geologic conditions will not unfavorably channel large earth currents and harmfully affect nearby populations. An optimum site allows direct contact between the electrode and a large volume of a stable, low‐resistivity material. A saturated alluvial zone between dry surface soils and an underlying crystalline bedrock is an ideal material for containing the current flow from the electrode.

A hydrogeologic investigation was conducted to delineate the saturated zone in several alluvial valleys in the southwestern desert region. Regional ground water flow directions, water quality, and seasonal fluctuations of the water table elevations were determined. The structural shape and topography of the crystalline basement beneath the valleys were interpreted from gravity data. Iterative forward‐modeling of the data provided a low‐cost means of deducing the volume of the lightweight alluvium. Electrical resistivity surveys were completed to measure the lateral and vertical variations in soil resistivities throughout the valleys. The geophysical data were used to extend the known hydrologic information into areas with no wells.

Composite models of the saturated zones in each valley were produced by integrating gravity interpretations with hydrologic and resistivity results. The composite models were used to predict current density in the ground that would be associated with a HVDC electrode. This methodology proved to be a cost‐effective means of siting electrodes in a suitable geologic environment that would minimize their detrimental effects.
Chemical Fate of Injected Wastes
Authors: Scrivner Noel C. , Bennett Karl E. , Pease Richard A. , Kopatsis Alex , Sanders Steven J. , Clark Diane M. , Rafal Marshall
Published: February 2007

The chemical fate of wastes put into disposal wells can be determined using standard chemical engineering techniques. The concentration of hazardous constituents is typically reduced by reactions within the waste itself or by reactions with the injection zone material, thus reducing any potential impact on the environment. Such reactions include neutralization, hydrolysis, ion exchange, adsorption, precipitation, co‐precipitation and microbial degradation.

Extensive research was done to quantify these phenomena, so they could be used in a predictive model.

Neutralization, hydrolysis and precipitation were modeled using data from the open literature: reaction rates and equilibrium constants for the dominant reactions were incorporated into a sophisticated computer simulation that calculates solid‐liquid equilibria of aqueous electrolyte solutions.

The model predicted the fate of two waste streams: (1) high‐pH, cyanide‐containing waste injected into sandstone is made less hazardous by hydrolysis and sand dissolution, and (2) FeCl3‐FeCl2 HCl‐H2 O waste is made non‐hazardous by reaction with dolomite. Experiments are planned to confirm certain model predictions. Further development and public access of the model are planned.
Theory, Construction and Operation of Simple Tensiometers
Authors: Stannard David I.
Published: February 2007

The tensiometer, introduced by Richards and Gardner (1936) has been a tool often ignored in unsaturated zone investigations. Hazardous waste disposal studies that require values of unsaturated zone matric potentials will expand tensiometer use. Familiarity with operation and installation principles is necessary to ensure quality data collection.

The essential elements of a tensiometer are a porous cup connected with tubing to a vacuum gauge; all are filled with water. When the porous cup is buried in unsaturated soil, the soil draws water through the cup wall, until the water tension inside the cup equals the surrounding soil‐water tension. The tension is transmitted through the water filled tube to an accessible vacuum gauge (manometer or transducer) and is recorded manually or automatically.

Although specialized tensiometers exist, the tensiometer presented here in detail is suited to diverse on‐site applications. Constructed from readily available, inexpensive parts, it can measure as much as 0.85 bar of tension. Design features include a flushing system for removal of entrapped air or mercury, and an easily maintained modular network of nylon manometers and water‐supply tubes.

Good hydraulic connection between porous cup and soil and meticulous backfill procedures are necessary for accurate measurement of representative matric potentials. Proper and consistent use of tensiometers should yield reliable values of matric potentials, and lead to a better understanding of unsaturated zone processes.
Suitability of Polyvinyl Chloride Well Casings for Monitoring Munitions in Ground Water
Authors: Parker Louise V. , Jenkins Thomas F.
Published: February 2007

A number of samples of polyvinyl chloride (PVC) well casings used for ground water monitoring that varied in schedule, diameter or manufacturer were placed in contact with low concentrations of aqueous solutions of TNT, RDX, HMX and 2,4‐DNT for 80 days. Analysis indicated that there was more loss of TNT and HMX with the PVC casing than with the glass controls, but that the amount lost was, for the most part, equivalent among different types. A second experiment was performed to determine if these losses were due to sorption or if biodegradation was involved. Several different ground water conditions were simulated by varying salinity, initial pH and dissolved oxygen content. The only case where there was an in‐creased loss of any substance due to the presence of PVC casing was with the TNT solution under non‐sterile conditions. The extent of loss was small, however, considering the length of the equilibration period. This increased loss is thought to be associated with increased microbial degradation rather than sorption. Several samples of PVC casing were also leached with ground water for 80 days. No detectable interferences were found by reversed‐phase high performance liquid chromatography (HPLC) analysis. Therefore, it is concluded that PVC well casings are suitable for monitoring ground water for the presence of these munitions.
Shallow Seismic Refraction Survey of Near‐Surface Ground Water Flow
Authors: Sverdrup Keith A.
Published: February 2007

A shallow seismic refraction survey was conducted as part of a geologic and hydrologic investigation of an area adjacent to a proposed coal strip mine in southeastern Illinois. Data obtained from the survey were used to estimate the thickness and geometry of litho‐logic units within approximately 40 feet of the surface in unconsolidated material overlying bedrock. Data from a nearby ground water monitoring well and several shallow geologic cores obtained in the survey area indicated the presence of a silt‐clay unit roughly 10 feet beneath the surface. This unit strongly inhibits the vertical movement of ground water, resulting in a perched water table.

The refraction survey revealed that the morphology of the top of this silt‐clay layer is dominated by a narrow, sinuous channel criss‐crossing the survey region with an overall downward trend in elevation from the mine site to a small creek roughly 0.25 miles away. Detailed knowledge of the location of this channel was used to identify optimal sites for shallow ground water monitoring stations. The method proved to be a relatively rapid and cost‐efficient means of obtaining detailed information concerning the thickness and geometry of the near‐surface unconsolidated materials.
A Low‐Cost System to Remotely Measure Piezometric Head
Authors: Schaefer Mark E. , Hemond H.F.
Published: February 2007

Alow‐cost rapid response system to remotely collect piezometric head data in compressible porous media has been constructed. The system is based on low‐cost temperature compensated pressure transducers, standard low‐cost CMOS logic devices, low‐cost commercially available two‐way radios and a portable microcomputer. The basic system operation involves encoding a pressure transducer output, which is then transmitted on command via two‐way FM radios to a base station located up to one‐half mile away. The base station includes a TRS‐80 Model 100 microcomputer which controls the network of remote stations and decodes and stores the information. This information is partially processed in the microcomputer and may be readily transferred to a mainframe for further data analysis. The base station interrogates as many as 16 remote stations at a specified sampling rate. The versatility of the system also allows it to be used to operate any remote instrumentation system having a suitable voltage output.
Electronic Sensing Devices Used for In Situ Ground Water Monitoring
Authors: Ritchey Joseph D.
Published: February 2007

Progress in the fields of electronics and computers has produced data‐acquisition equipment beneficial to ground water field studies. This equipment controls data collection from sensing devices and saves the data for later processing. There are many types of sensors available for in situ use in water quality monitoring wells, observation wells and water supply wells. Sensors are separated into two groups, those used to measure water levels and those used to measure water quality parameters.

There are three major types of sensors for measuring water levels. They are floats, transducers and acoustic devices. Most types have proven accuracy and can be successfully applied to short‐term monitoring (i.e., aquifer tests) and long‐term field studies (i.e., one month to multi‐year trend analyses). They are most cost‐effective when augmented with the programmability of computers. For example, water level measurements are made only when the water level has changed some predetermined amount.

Sensors to measure water quality include those that measure temperature, pH, specific conductance, dissolved oxygen and specific ions. Unlike water level sensors the accuracy of water quality sensors, with the exception of temperature, is difficult to verify in field conditions. This is because measurement of water quality parameters is dependent on the water in contact with the sensor being representative of the ground water in the formation. In addition, the performance of the sensor over periods greater than a few hours is reduced either because of the naturally occurring constituents in the water that interfere with the sensor or because of loss of sensor calibration.

A potential use of water quality sensors for in situ investigations is to aid in surveillance monitoring to indicate the arrival of contaminants at the earliest possible moment. This has a narrow limit of practicality at this time because of problems associated with sensor accuracy.

Many water quality sensing devices are well‐suited for research purposes. This includes measuring the migration of thermal fronts and application in conducting tracer tests.
An In Situ Multilevel Sampler for Preventive Monitoring and Study of Hydrochemical Profiles in Aquifers
Authors: Ronen Daniel , Magaritz Mordeckai , Levy Itzhak
Published: February 2007

Abstract

A modular multilevel sampler was developed and utilized for sampling undisturbed ground water chemical profiles and gases in both the saturated and the unsaturated zone. Sampling at 3cm depth intervals is based on the dialysis‐cell method and has no depth limitations. The sampler may be used for the development of early warning monitoring systems and research.
Simulation of Sampling and Hydraulic Tests to Assess a Hybrid Monitoring Well Design
Authors: Cohen Robert M. , Rabold Richard R.
Published: February 2007

Determination of the nature, extent, and rate of off‐site chemical migration are common objectives of hazardous waste site investigations. Chemical analyses of water samples from monitoring wells and measurements of hydraulic head and hydraulic conductivity provide the basis for making these determinations. Accurate site assessment, therefore, depends upon the appropriate monitoring well design and sampling and testing procedures.

During the course of remedial investigations in Niagara Falls, New York, it has been necessary to evaluate the ground water quality and hydraulic characteristics of 5‐ to 30‐feet thick overburden formations. Many of the monitoring wells completed to these formations consist of a partially penetrating screen (5 feet at the base of the formation) with a fully penetrating sandpack. Questions regarding how this well design influences the source of sampled ground water and hydraulic tests were examined using an extremely fine axisymmetric grid with SATURN, a two‐dimensional, finite‐element ground water model, and a particle tracking post‐processor.

A discrete sensitivity analysis was made to determine how flow patterns induced by pumping at 1 gpm are affected by: different screen and sandpack configurations, the ratio of sandpack to formation hydraulic conductivities, heterogeneity, anisotropy, and sandpack thickness. The simulations show that the source (and chemistry given a non‐uniform chemical distribution) of ground water sampled will vary considerably depending on a number of factors. Analysis of simulated drawdowns in the monitoring well during purging shows that calculated transmissivities for the range of well designs and conditions modeled will be accurate to within one‐half order of magnitude.
The Effect of Construction, Installation, and Development on the Turbidity of Water in Monitoring Wells in Fine‐Grained Glacial Till
Authors: Paul Duane G. , Palmer Carl D. , Cherkauer Douglas S.
Published: February 2007

Twenty monitoring wells were installed in fine‐grained glacial till at two sites in southeastern Wisconsin to study the effects of monitoring well construction, installation, and development on the amount of fine‐grained suspended material in the well. The types of well screens used were continuous slot, factory slot, factory slot with a filter wrap, and porous piezometer tips. Some of the wells were installed before the open borehole began to fill with water; others were installed after the water levels in the lower section of the borehole had begun to rise. About half of the wells were developed by surging while the others were simply bailed without surging. Installation of the wells in the initially dry holes resulted in wells that yielded samples with very low turbidity compared to wells installed in wet holes. Water samples from wells that were surged were more turbid than those that were not. The type of construction materials investigated had no effect on the turbidity of samples from the wells.
Monitoring the Vadose Zone in Fractured Tuff
Authors: Montazer Parviz , Weeks E.P. , Thamir Falah , Hammermeister Dale , Yard S.N. , Hofrichter Peter B.
Published: February 2007

Unsaturated tuff beneath Yucca Mountain, Nevada, is being evaluated by the U.S. Department of Energy as a host rock for a potential repository for high‐level radioactive waste. As part of the Nevada Nuclear Waste Storage Investigations Project of the U.S. Department of Energy, the U.S. Geological Survey has been conducting hydrologic, geologic and geophysical investigations at Yucca Mountain and the surrounding region to provide data for evaluation of the potential suitability of the site. Hydrologic investigations of the unsaturated zone at this site began in 1982. A 17.5‐inch‐ (44.5‐centimeter) diameter borehole (USW UZ‐1) was drilled by the reverse‐air vacuum‐drilling technique to a depth of 1269 feet (387 meters). This borehole was instrumented at 33 depth levels. At 15 of the levels, three well screens were embedded in coarse‐sand columns. The sand columns were isolated from each other by thin layers of bentonite, columns of silica flour, and isolation plugs consisting of expansive cement. Thermocouple psychrometers and pressure transducers were installed within the screens and connected to the data‐acquisition system at the land surface through thermocouple and logging cables. Two of the screens at each level were equipped with access tubes to allow collection of pore‐gas samples. In addition to these instruments, 18 heat‐dissipation probes were installed within the columns of silica flour, some of which also had thermocouple psychrometers.

After more than two years of monitoring, the majority of the instruments were still functioning and producing reasonable data. A slow recovery from the disturbed state to natural conditions was detected during the first 90 days of monitoring; this recovery was probably a result of the large diameter of the borehole. Preliminary results indicated that suction pressures for the welded units ranged from −2 to −15 bars (−0.2 to −1.5 mega pascals). Some agreement existed between data from psychrometers and from heat‐dissipation probes, except where silica flour was not in equilibrium with the formation. Water fluxes estimated in the matrix of the repository host‐rock unit range from 4 × 10−3 to 2 × 10−2 inches per year (0.1 to 0.5 millimeter per year) using matric‐potential distribution, and from −1 × 10−3 to −2 × 10−3 inches per year (−0.025 to −0.05 millimeter per year) using geothermal gradient.

Responses to short‐term barometric fluctuations were detected to a maximum depth of about 300 feet (91 meters) in the borehole. Below this depth, only long‐term barometric fluctuations were detectable. Equivalent effective hydraulic conductivity, estimated from air permeability, ranged from 0.6 to 2 feet per day (0.2 to 0.6 meters per day).
Design of Lysimeter Leak Detector Networks for Surface Impoundments and Landfills
Authors: Bumb Amar C. , McKee Chester R. , Evans Roy B. , Eccles Lawrence A.
Published: February 2007

Sampling of soil pore moisture in the vadose zone underneath land disposal facilities (landfills and surface impoundments) for hazardous waste has been suggested as an “early warning system” to detect leakage from these facilities. Some states require vadose zone moisture sampling at such sites. Given a leak of a particular size, mathematical models can estimate the necessary moisture sample volume collection times and lysimeter spacings to guarantee detection of the leak in a homogeneous medium. Examination of 47 hazardous waste sites existing in 1984 indicated the most were located in areas with water tables too shallow to permit vadose zone detection monitoring. Several of the 47 sites had soils that could be described as loamy sand, silt loam or silty clay. Using these three soils as examples, the process of lysimeter leak‐detector network design has been illustrated. For a particular loamy sand with a saturates hydraulic conductivity of 10‐6 cm/ sec, the maximum ceramic lysimeter spacing is 15.5 feet at a depth of 30 feet to collec a moisture sample of 10 mL in one week from a 1 ft2 leak. For a silt loam, maximum lysimeter spacing would be 17 feet at depth of 15 feet. For silty clays, the maximum lysimeter spacing is 7 feet at a depth of 2 feet; maximum emplacement depth is about 9 feet. Calculations show that in some soils, suction lysimeters will not be able to collect usable moisture samples. Since soil properties vary widely and lysimeter spacing is strongly dependent on soil‐moisture characteristics appropriate soil measurements and modeling must be performed at each disposal facility to estimate lysimete performance and to select locations for emplacement.
Simulation of Vapor Transport Through the Unsaturated Zone — Interpretation of Soil‐Gas Surveys
Authors: Silka Lyle R.
Published: February 2007

Soil‐gas surveys are becoming more widely accepted as a tool for the preliminary determination of the extent of soil and ground water contamination by volatile organic compounds (VOCs). The interpretation of the results of published soil‐gas surveys has been necessarily limited and qualitative due to a lack of adequate models. There has been considerable effort in the recent past to characterize the transport and fate of pesticides in soil. However, the behavior of pesticides generally differ substantially from those of VOCs.

This paper presents a computer model developed to simulate the diffusive transport of VOC vapor through unsaturated soils using a two‐dimensional, finite‐difference, solution to Fick's second law of diffusion. An effective diffusion coefficient that incorporates the effects of tortuosity, moisture content, and soil organic carbon content is computed. Although the model has not been validated due to the unavailability of adequate field or laboratory data, nevertheless, sensitivity analyses demonstrate the importance of soil moisture and, secondarily, organic matter content in controlling the migration of VOC vapor through the unsaturated zone. The interpretation of soil‐gas surveys can be complicated by unknown spatial heterogeneities in soil moisture and organic carbon content, temporal variations in moisture content, extent of contaminant migration as a non‐aqueous phase liquid and by the unknown extent of VOC liquid and contaminated ground water.