bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of lowered salinity and elevated cadmium on the survival and metamorphosis of trochophores in Capitella sp. I
Authors: Pechenik Jan A. , Berard Richelle , Daniels Dara , Gleason Timothy R. , Champlin Denise
Published: August 2005

Abstract. It is well known that the competent larvae of many marine invertebrate species can be stimulated to metamorphose by exposing them to elevated concentrations of certain ions, neuroactive substances, and pharmacological agents. In this study we report that larvae of the euryhaline polychaete Capitella sp. I are induced to metamorphose within 24–48 h by reducing salinity from 30%‰ to 12–15%‰. At 10%‰, however, fewer larvae metamorphosed and the normal metamorphic response to sediment was inhibited; competence was restored within 3 h of transferring the larvae back to full strength seawater (30%‰). Larvae also metamorphosed within 24 h in response to increased external cadmium concentrations of 1000–2000 μg 1–1. Further understanding of how reduced salinity and elevated cadmium stimulate (or inhibit) metamorphosis may lead to a better understanding of signal perception and transduction in this and other species.
Partial characterization of the secretory material from the dorsal bodies in the snail Helisoma duryi (Mollusca: Pulmonata), and its effects on reproduction
Authors: Mukai Spencer T. , Steel Colin G.H. , Saleuddin A. Saber M.
Published: August 2005

Abstract. Both dorsal body tissue extracts and dorsal body‐conditioned medium stimulated in vitro polysaccharide synthesis in albumen gland explants in Helisoma duryi. This activity is heat‐ and protease‐resistant. Dorsal body tissue extracts and dorsal body‐conditioned medium were passed through solid‐phase extraction cartridges, then eluted with increasing concentrations of methanol (20%, 70%, and 100%) and the various eluates tested for their biological activity. An active factor was found in the 100% methanol wash from both dorsal body tissue extracts and the conditioned medium. In addition, another bioactive factor in the conditioned medium eluted with 70% methanol. The endocrine dorsal bodies in the freshwater snail H. duryi were maintained in vitro, and following incubation, the culture medium was collected and tested for the presence of ecdysteroids. Radioimmunoassay of the culture medium demonstrated the presence of ecdysteroid‐like immunoreactivity, suggesting the dorsal bodies are capable of secreting ecdysteroids in vitro. Identification of released ecdysteroids by HPLC/RIA revealed a number of immunoreactive fractions, which were tested for bioactivity. To test for possible physiological functions of ecdysteroids in Helisoma duryi, 20‐hydroxyecdysone (a potent ecdysteroid in arthropods) was injected into non‐egg laying (virgin) snails. Injections of ecdysteroid induced low egg‐laying activity and the maturation of oocytes in the ovotestis. Incubation of albumen glands with ecdysteroid stimulated polysaccharide synthesis. The results are discussed in relation to the possible function(s) of ecdysteroids in pulmonate snails.
Apical antennal sensilla in nymphs of Libellula depressa (Odonata: Libellulidae)
Authors: Gaino Elda , Rebora Manuela
Published: August 2005

Abstract. In an ultrastructural study of the apical antenna of the last nymphal stages of Libellula depressa (Odonata: Libellulidae), we found long sensilla trichodea, 2 sensory pegs, and a coeloconic sensillum on the last article of the flagellum (the distal part of the antenna). The long sensilla trichodea are mechanoreceptors, almost identical to the long filiform hairs of some terrestrial insects and the first sensilla of this kind to be described in aquatic insects. Particular attention was given to the complex coeloconic sensillum, a compound sensillum innervated by 2 groups of 3 neurons wrapped in a dendritic sheath. A cuticular sleeve envelops the distal portion of the outer dendritic segment. The cuticle of the coeloconic sensillum shows wide channels and is contiguous to the underlying granular and fibrillar layer. Similar structures on the antennae of the adults of other dragonflies were identified as chemoreceptors in previous studies. We hypothesize that this larval coeloconic sensillum might likewise have a chemosensory function, responding to molecules that diffuse through the cuticle and the underlying granular and fibrillar layer, as no clear pore or pore‐tubule system is visible. Alternative functions are also explored on the basis of morphological details.
Prey attraction by larvae of the New Zealand glowworm, Arachnocampa luminosa (Diptera: Mycetophilidae)
Authors: Broadley R. Adam , Stringer Ian A.N.
Published: August 2005

Abstract. The hypothesis that bioluminescence produced by larvae of the New Zealand glow‐worm, Arachnocampa luminosa, attracts prey was tested experimentally in Reserve Cave, Waitomo, New Zealand, and in its bush‐clad entrance over a total of 200 days during winter, spring, and summer. We compared catches on transparent adhesive traps placed either over glowworms or over areas from which glowworms had been removed. Adhesive traps over glowworms caught significantly more invertebrates per trap per day than did control traps. Glowworms in bush attracted greater numbers and types of invertebrates than did glowworms in the cave. Diptera predominated in both bush (86% of the total catch) and cave (89%). Also caught were small numbers of Araneae, Coleoptera, Hymenoptera, Orthoptera, Trichoptera, Gastropoda, Acarina, and Neuroptera—listed in order of abundance—but no adults of A. luminosa were caught. Glowworms under adhesive traps survived with little or no food for up to 78 days.
Induced inflammatory process in the sea urchin Lytechinus variegatus
Authors: Mangiaterra Maria B.B.C.D. , Silva José R.M.C.
Published: August 2005

Abstract. In vitro and in vivo studies confirmed endocytic activity of free phagocytic amebocytes in Lytechinus variegatus. Amebocytes in the perivisceral coelom were labeled with injected ferritin, and ferritin‐labeled amebocytes were found in the peristomial connective tissue only one hour after injection of India ink or yeast into this tissue. The presence of ferritin inside the amebocytes indicates that these cells migrated from the perivisceral coelom to the peristomial connective tissue. After 24 hours, particles of India ink or yeast were observed inside the ferritin‐labeled amebocytes, indicating the amebocytes' ability to respond to an inflammatory stimulus. These were the only inflammatory cells found in L. variegatus, using the above mentioned stimuli and time spans.
The peripheral nervous system of an ascidian, Botryllus schlosseri, as revealed by cholinesterase activity
Authors: Burighel Paolo , Sorrentino Marina , Zaniolo Giovanna , Thorndyke Michael C. , Manni Lucia
Published: August 2005

Abstract. In this study we present the first detailed description of the motor component of the peripheral nervous system of an ascidian showing its three‐dimensional organization and the spatial relationships between nerves and contiguous organs. Nerves of the oozooid and blastozooid of the colonial ascidian Botryllus schlosseri were analyzed using a histochemical method for detecting cholinesterase activity in whole‐mount preparations and in sections for light and electron microscopy. Except for the neural gland and gonads, all tissues are well innervated by cholinesterase‐reactive neurites. Each blastozooid of the colony possesses an individual nerve plexus which is not in continuity with that of adjacent zooids. The innervation of the mantle, oral and cloacal siphons, branchial basket, heart, and gut are described. Most organs possess a complex network of nerves often with multiple origins from different pathways. A sophisticated pattern is described for the first time in the gut, which receives innervation from the endostyle, the roof of the branchial basket, and the posterior mantle. Dilated axonal regions but no obvious cell bodies were recognized in the peripheral nervous system revealed by cholinesterase activity. The localization of nerves is discussed together with a consideration of their physiological role.
Introduction to Sevelamer Hydrochloride and its Clinical Effects
Authors: Tahara Hideki , Tsujimoto Yoshihiro , Shoji Tetsuo , Inaba Masaaki , Tabata Tsutomu , Nishizawa Yoshiki
Published: August 2005

Abstract:  Sevelamer hydrochloride (SH) is widely used for the treatment of hyperphosphatemia in patients with renal failure who are on maintenance hemodialysis. In this study, we investigated the clinical effects of SH, administered as either monotherapy or combined with a calcium carbonate formulation, on the metabolism of calcium (Ca) and phosphorus (P) in patients who had been taking a Ca‐based binder. Patients were divided into three groups (i): switched completely from a Ca‐based binder to SH (complete switch); (ii) dosage of the Ca‐based binder was reduced, and SH introduced (partial switch); and (iii) dosage of the Ca‐based binder was not reduced and SH introduced (combination therapy). We also examined the effects of the introduction of SH on the lipid profile and parathyroid hormone (PTH) concentration. Comparison between groups of the numbers of successfully treated cases (reaching target concentrations of serum P = 5.5 mg/dL and Ca × P product = 55 mg2/dL2 within 6 months of treatment) showed that the likelihood of reaching target levels was higher if Ca‐based binder was maintained as much as possible (combination therapy > partial changeover > complete changeover). Furthermore, treatment with SH decreased total cholesterol and non‐HDL cholesterol concentrations significantly, and also increased HDL cholesterol and PTH concentrations compared to pre‐treatment. These results suggest that when a calcium carbonate formulation is already in use, as far as compliance allows, the dosage should not be reduced when SH is added. Despite its beneficial effects on the lipid and PTH concentrations, preventing an excessive increase in the PTH concentration is essential when using SH.
Impact of Sevelamer Hydrochloride and the K/DOQI Guidelines
Authors: Yumita Shigeru
Published: August 2005

Abstract:  Sevelamer hydrochloride (SH) was registered as a new drug under the Japanese national health insurance scheme in 2003, and the Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines for the treatment of renal osteodystrophy were released the same year. At that time, treatment objectives for hemodialysis outpatients at the Kojinkai Ishimaki Clinic were settled established and the outcomes reviewed 18 months later. The relationship between the type and dosage of phosphate binder (PB), and the concentrations of adjusted calcium (Ca), phosphorus (P), intact parathyroid hormone (PTH), and bone alkaline phosphatase (BAP) was examined. Patients receiving calcitriol or maxacalcitol intravenous pulse therapy, or who had undergone simultaneous pancreas–kidney transplant, were excluded from this analysis. The PB was CaCO3 in 60% of cases, SH in 33.3%, and a combination of both in 21.9%; no PB was used in 6.7% of cases. The dosage of CaCO3 was 2.8 ± 1.0 g/day, and 1α‐hydroxy activated vitamin D3 (VD) was 0.46 ± 0.24 µg/day; the respective concentrations of adjusted Ca, P, intact PTH, and BAP were 9.4 ± 0.7 mg/dL, 5.6 ± 1.7 mg/dL, 104 ± 83.9 pg/mL, and 22.7 ± 10.9 IU/L. In the SH monotherapy group, the dosage of SH was 3.9 ± 0.725 g/day, and VD 0.62 ± 0.21 µg/day, and the concentrations for adjusted Ca, P, intact PTH, and BAP were 9.6 ± 0.4 mg/dL, 6.2 ± 1.5 mg/dL, 150 ± 42.9 pg/mL, and 38.5 ± 14.2 IU/L, respectively. In the combined therapy group, the dosage of CaCO3 was 2.9 ± 0.9 g/day, SH was 3.3 ± 1.1 g/day, VD was 0.53 ± 0.27 µg/day, and the respective concentrations were 9.2 ± 1.0 mg/dL, 5.7 ± 1.4 mg/dL, 160 ± 107.8 pg/mL, and 31.3 ± 42.0 IU/L. One‐third of all subjects were administered SH, either as monotherapy or in combination with CaCO3, and in these patients the dosage of VD was able to increase.
Parathyroid Interventions for Secondary Hyperparathyroidism in Hemodialyzed Patients
Authors: Onoda Noritaka , Kashiwagi Tetsuya , Nakamura Tadashi , Niitsu Yoshifumi , Omata Momoyo , Kurihara Satoshi
Published: August 2005

Abstract:  Although parathyroidectomy (PTX) is the ultimate treatment for secondary hyperparathyroidism (SHPT) that is resistant to medical treatment, recent advances in ultrasonographic techniques have increased the treatment options in Japan. Percutaneous ethanol injection therapy (PEIT) of the parathyroid was approved under the national health insurance system in 2004, and there have been trials of direct injection of vitamin D (VD) preparations. We followed 30 patients for at least 1 year who had undergone PEIT at the same institution. The overall mean concentration of intact parathyroid hormone (PTH) fell from 865.3 ± 388.4 pg/mL to 291.9 ± 277.8 pg/mL, or 34% of the pretreatment value. The effect was even more pronounced for one or two glands, with 68.4% reaching the target of intact PTH ≤ 300 pg/mL recommended in the K/DOQI guidelines, in comparison with 36.4% of cases of hypertrophy of three or four glands. The average time taken to achieve the target PTH concentration was 4 months. No correlation was found between the response to PEIT and the total parathyroid volume, or the volume of glands with suspected nodular hyperplasia. Cases in which PTH does not fall sufficiently after five or more injections should be considered refractory to PEIT and evaluated for PTX. Following PEIT, PTH falls relatively slowly, whereas after total PTX with forearm autograft the PTH concentration falls immediately and may still be less than 60 pg/mL 4 or 5 years later. Bone biopsies performed 1 year after total PTX with autograft showed a change from an osteitis fibrosa pattern to an adynamic bone disease pattern. In some cases of hypertrophy of three to four glands, markers of bone metabolism kept decreasing more than did PTH, corresponding to marked improvement in the patients’ quality of life. Important considerations for treatment selection include: (i) ultrasonography of the cervical region as screening; (ii) earlier recognition of the limits of medical therapy; and (iii) the number of affected glands, the age of the patient, and the likely course postintervention.
Parathyroid Cell Growth in Patients with Advanced Secondary Hyperparathyroidism: Vitamin D Receptor, Calcium Sensing Receptor, and Cell Cycle Regulating Factors
Authors: Tokumoto Masanori , Taniguchi Masatomo , Matsuo Dai , Tsuruya Kazuhiko , Hirakata Hideki , Iida Mitsuo
Published: August 2005

Abstract:  The parathyroid gland (PTG) is a unique endocrine organ in which the quiescent glandular cells begin to proliferate in rsponse to the demand for maintaining calcium (Ca) homeostasis in the progressive course of renal failure, leading to secondary hypereparathyroidism (SHPT). SHPT is characterized with continuous over‐secretion of parathyroid hormone (PTH) and high turn‐over bone disease, osteitis fibrosa, and the major factors include a deficiency of active vitamin D, hypocalcemia, and phosphate retention. With long‐term end‐stage renal failure, SHPT becomes resistant to conventional medical treatment such as phosphate binders and active vitamin D supplementation, and the growth of the PTG accelerates with the pattern of hyperplasia changing from diffuse to nodular type. In this process, the sigmoid curve between extracellular Ca concentration (exCa) and the plasma level of PTH shifts to the upper‐rightward, indicating both an absolute increase in PTH secretion and the resistance of PT cells to exCa. Many experimental and human studies have revealed down‐regulation of vitamin D receptor (VDR), calcium‐sensing receptor (CaSR), and retinoid X receptor (RXR) in PT cells. The sustained proliferation of PT cells after obtaining autonomicity is another characteristic feature of SHPT. In this context, it has been demonstrated that the cell cycle is markedly progressed, where the expression of cyclin‐dependent kinase inhibitor (CDKI), p21 and p27, is depressed in a VDR‐dependent manner. These pathological features are most evident in nodular hyperplasia, in which monoclonal proliferation is obvious, indicating the phenotypic changes have occured in PT cells. It has been observed by Fukagawa and colleagues that pharmacologically high dose of active vitamin D administered orally can cause small‐size PTG hyperplasia to regress in patients with advanced SHPT. Successful renal transplantation may also restore VDR and CaSR expressions in the diffuse type, in association with increasing TUNEL‐positive cells. Thus, it is important to vigorously treat SHPT when the PT cell proliferation is in the reversible stage of diffuse hyperplasia.
Management of Secondary Hyperparathyroidism
Authors: Cunningham John
Published: August 2005

Abstract:  Secondary hyperparathyroidism (SHPT) remains an inevitable consequence of untreated chronic uremia. It is the result of a combination of phosphate (P) retention, failure of calcitriol synthesis, and hypocalcemia. Therapies used to correct these abnormalities, namely active vitamin D replacement, calcium (Ca) supplementation, and phosphate (P) restriction, have moderate efficacy but are prone to unacceptable side‐effects. However, there have been new developments in the control of P, vitamin D replacement and modulation of the Ca sensing receptor (CaSR) using calcimimetics. Sevelamer, and in the near future lanthanum, are offering a reasonable level of P control without the toxicities inherent with either aluminum‐ or Ca‐based phosphate binders, and other phosphate binders are in development. ‘Non calcemic’ vitamin D metabolites include 22‐oxacalcitriol, paricalcitol, and doxercalciferol. In various experimental models 22‐oxacalcitriol, in particular, exhibits impressive suppression of parathyroid hormone (PTH) with minimal calcemia, although it has been less impressive when compared with calcitriol in controlled studies in hemodialysis (HD) patients. The advantages of these agents over conventional treatment with calcitriol or alfacalcidol remain uncertain. Cinacalcet, a calcimimetic agent that up‐regulates the sensitivity of the CaSR in parathyroid and other cells, is a new type of therapy for SHPT that simultaneously reduces the concentrations of PTH, Ca, and P in HD patients, enabling a significant number to achieve K/DOQI or other national guidelines. The extent to which this new therapy will improve clinical outcomes remains uncertain. In conclusion, with the advent of new therapies the emphasis in the management of SHPT has evolved to incorporate reduction of Ca loading, control of PTH within specific target ranges, and avoidance of hypercalcemia, hyperphosphatemia and elevation of the calcium phosphorus product.
Role of Sevelamer Hydrochloride in the Coronary Artery Calcification Score
Authors: Tsuruta Yoshinari , Kaneshiro Kana , Narita Yukio , Obayashi Takaaki , Fujii Mikiko , Narita Masayasu , Sasai Kanna , Yoshimata Takayuki , Watanabe Yuzo , Maeda Kenji
Published: August 2005

Abstract:  The coronary artery calcification score (CACS) is higher in hemodialysis (HD) patients than in non‐HD patients for each age group from the fifth to the eighth decade of life. In order to clarify the relationship between the rate of change in the CACS and several factors related to calcium (Ca) and phosphate (P) metabolism in HD patients, we determined the CACS twice in 144 HD outpatients at an interval of approximately 12 months (2003 and 2004). The dosage of vitamin D formulations (alfacalcidol or maxacalcitol) was reduced or ceased if the serum Ca concentration exceeded 5.0 mEq/L, or the serum P concentration exceeded 6.0 mg/dL, and the dosage of combined sevelamer hydrochloride (SH) and calcium carbonate (CaCO3), as the phosphate binder, was adjusted to maintain the concentrations below these levels. The study parameters were: (1) the total dosage of alfacalcidol (µg), maxacalcitol (µg), SH (mg), and CaCO3 at the time of each CACS measurement; and (2) serum concentrations of Ca, P, alkaline phosphatase, high‐sensitivity parathyroid hormone (HS‐PTH), total protein, albumin, total cholesterol, triglycerides (TG). Regression analysis showed a significant correlation among the total SH dosage, TG, and αCACS. Future investigations will include the differences in αCACS between patients treated with SH who experience a rise in Ca and/or P and those with a decrease in Ca and/or P.
Management of Calcium, Phosphorus and Bone Metabolism in Dialysis Patients Using Sevelamer Hydrochloride and Vitamin D Therapy
Authors: Ishida Mari , Yao Naoyuki , Yachiku Setsuko , Anzai Tsutomu , Kobayashi Takeshi , Ishida Hironori
Published: August 2005

Abstract:  Abnormalities of mineral metabolism, including those of calcium (Ca), phosphorus (P), and parathyroid hormone (PTH) in patients on maintenance hemodialysis induce severe bone involvement, which manifests as renal osteodystrophy. Recently, vascular calcification caused by abnormal mineral metabolism has been attracting attention because cardiovascular diseases (CVD) are a major cause of death in hemodialysis patients. Since 2000, the treatment standard for overt secondary hyperparathyroidism (SHPT) in our facilities has shifted from conventional or pulse therapy with oral vitamin D3 (VitD) to intravenous pulse therapy with maxacalcitriol or calcitriol. After selecting the criterion of overt SHPT as intact‐PTH > 500 pg/mL, the proportion of overt SHPT cases among all hemodialysis patients decreased from 12% at the start of intravenous pulse treatment to 6.4% after 4 years’ treatment. However, the number of patients who had an interruption to pulse treatment because of hypercalcemia and/or hyperphosphatemia was high and it became a bottleneck for the continuation of the therapy. The major cause of hypercalcemia is considered to be Ca load derived from oral calcium carbonate. In Japan, sevelamer hydrochrolide (SH), which does not contain Ca, has been available commercially since 2003 and potentially should enable a reduction in the incidence of overt SHPT during long‐term intravenous treatment when combined with careful adjustment of the dose of VitD and strict monitoring of Ca and P level concentrations. In this study, we found that the proportion of patients who satisfy the recommended serum concentrations of Ca and P reported by K/DOQI guideline was low irrespective of the serum concentration of intact‐PTH. The aortic calcification index was high in the patient group with lower intact‐PTH level concentration, probably because of reduced Ca and P buffering ability associated with reduced bone turnover. We consider that VitD treatment with SH might give better control of the intact‐PTH level concentration within the range recommended by the K/DOQI guideline.
Observations of Delayed Gravity Response in Partially Penetrating Wells
Authors: Mock Peter , Merz Jeanne
Published: August 2005

A 72‐hour aquifer test was conducted at the Sweet‐water Recharge site in Tucson, Arizona for the purpose of estimating aquifer parameters using the graphical curve‐matching technique of Neuman (1974). These parameter estimates will be used to estimate the movement of ground water under seasonal recharge and recovery operations at the site. The lithology of the saturated sediments at the site appears to be relatively uniform and homogeneous from the water table at about 100 feet below land surface to about 600 feet below land surface. The aquifer base is a finegrained unit which extends from 600 feet to an unknown depth below the site. Poorly sorted sandy gravels and gravelly sands are predominant above 600 feet. A well was pumped at an average rate of 2,020 gallons per minute for 72 hours. Drawdown and recovery measurements of water levels were made in five shallow monitoring wells and one deep monitoring well.

The log‐log drawdown versus time plots indicated delayed gravity response. The method of Neuman (1974) was used to estimate aquifer parameters from the test results. Because the pumped and monitoring wells were characterized by varying degrees of partial penetration, the computer program code developed by Neuman (1974) called DELAY2 was used to generate type curves for the unique arrangement of wells at the site.
Extraction of TCE‐Contaminated Ground Water by Subsurface Drains and a Pumping Well
Authors: Meiri David , Ghiasi Mansour , Patterson Ronald J. , Ramanujam Narayan , Tyson Mary P.
Published: August 2005

Ground water in a shallow glacial till aquifer and a deeper weathered shale aquifer at a site near Rock Creek, Ohio has been contaminated with trichloroethylene (TCE). Evaluation of remedial alternatives indicated that a system of subsurface drains would be most effective for decontaminating the shallow ground water. The performance of the proposed subsurface drainage system for the shallow aquifer was simulated using finite‐element flow and transport models. Model results indicate that the drains should reduce TCE concentration in the shallow aquifer to about 8 ppb in approximately 24 years.

A single extraction well was the selected alternative to remediate trichloroethylene concentrations in the deeper weathered shale aquifer. The performance of the proposed well was analyzed by an analytical method. Results of the analysis indicated that the extraction well should reduce contamination in less time than required for the shallow glacial till aquifer. Validation of the predicted performance of the remedial system will be assessed following installation of the system and collection of field data.
A Laboratory and Numerical Investigation of Solute Transport in Discontinuous Fracture Systems
Authors: Robinson J. W. , Gale J. E.
Published: August 2005

Mixing of fluids at fracture intersections was examined using both a series of plexiglass models and a two‐dimensional, finite‐element, discrete fracture model. The physical laboratory models included 12 models having two continuous, fully intersecting fractures with different intersection angles and apertures, a single model consisting of a single continuous fracture offsetting a second fracture, and a fracture system model consisting of parallel fractures in two intersecting sets. The plexiglass model results indicated essentially no mixing occurred in the fully intersecting fracture models when the apertures were equal. Mixing was found to be dependent only upon the relative size of the inlet and outlet fractures even with multiple intersections.

For transport of a conservative solute in a discontinuous, random, discrete fracture system, the numerical model used the mixing algorithm for fracture intersections, developed from the physical model study. At each four‐way intersection, a novel approach was used to uncouple and recouple the nodal points to ensure the proper assignment of concentrations to each fracture element. Using the laboratory‐determined mixing algorithm, the numerical model demonstrated that more longitudinal and less lateral dispersion takes place than when complete mixing at fracture intersections is assumed. In addition, more longitudinal transport takes place in discontinuous than in continuous fracture systems. These findings indicate that contaminants migrating through fractured media, where the fracture walls are not in contact, will not be dispersed and diluted to the extent that previous numerical models have predicted; hence, the contaminant will be discharged to the biosphere in much greater concentration than expected.
Simulated Effects of Quarry Dewatering Near a Municipal Well Field
Authors: Eberts Sandra M. , Bair E. Scott
Published: August 2005

The City of Columbus, Ohio, obtains nearly 15 percent of its municipal water supply from four radial‐collector wells located along the Scioto River and Big Walnut Creek. Upstream from the three wells located adjacent to the Scioto River are five uncontrolled landfills and two aggregate mines that operate quarry‐dewatering systems. Flow paths along which leachate could migrate from the landfills, under existing conditions and under various hypothetical conditions related to the cessation of quarry dewatering, were simulated with a two‐layer, steady‐state, ground‐water flow model incorporating spatially variable recharge, transmissivity, and hydraulic conductivity. The model was calibrated with two sets of water‐level data and with the results of a seepage study along the Scioto River and Scioto Big Run. Results of simulations indicate that water levels near the quarries and landfills will rise to an altitude sufficient to saturate some of the landfill wastes. Predicted flow directions associated with all the hypothetical conditions indicate that leachate migrating from the landfills will not discharge directly into the capture zones of the collector wells; rather, the leachate will be diverted into one or the other quarry‐dewatering systems and/or into the Scioto River. The model simulations also indicate that approximately 60 percent of the ground water discharged within the study area is by quarry dewatering, and about 13 percent of the yield of the collector wells under normal pumping rates is from induced stream infiltration.
Volume Estimation of Light Nonaqueous Phase Liquids in Porous Media
Authors: Farr A. M. , Houghtalen R. J. , McWhorter D. B.
Published: August 2005

An analytic method is described for estimating the volume of mobile Light Nonaqueous Phase Liquids (LNAPL) in porous media from observed LNAPL thicknesses in monitoring wells. Static (mechanical) equilibrium of fluids in a homogeneous porous medium is the key condition on which the method is based. Both the Brooks‐Corey and van Genuchten equations, with parameters derived from laboratory column experiments reported in the literature, are used to relate fluid contents to capillary pressures. The calculations show that LNAPL in the vadose zone does not distribute itself as a distinct layer floating on the top of a capillary fringe. Rather, the traditional concept of a capillary fringe is not applicable when LNAPL is present. Further, neither the LNAPL level nor the water level in monitoring wells is equal to the water‐table elevation. The water table, being the surface on which the water pressure is zero gage, is located above the LNAPL‐water interface in the well, and LNAPL in the porous media will reside below the water table.

It is shown that finite volumes of LNAPL theoretically can exist in materials with positive entry pressures (e.g., Brooks‐Corey porous media) without revealing their presence in the form of an LNAPL layer in monitoring wells. However, LNAPL in porous media with zero entry pressure will always appear in monitoring wells, regardless of the volume of LNAPL in the porous medium. In addition, the theory shows that the ratio of the volume of LNAPL per unit area in the vadose zone to the thickness of LNAPL in monitoring wells is strongly dependent upon the capillary properties of the porous medium. Only in porous media with very uniform pore sizes is the volume of LNAPL in the vadose zone approximately proportional to the thickness of LNAPL in monitoring wells.
Estimation of Free Hydrocarbon Volume from Fluid Levels in Monitoring Wells
Authors: Lenhard R. J. , Parker J. C.
Published: August 2005

Under the assumption of local vertical equilibrium, fluid pressure distributions specified from well fluid levels in monitoring wells may be used to predict water and hydrocarbon saturation profiles given expressions for air‐water‐hydrocarbon saturation‐pressure relations. Vertical integration of the oil‐saturation profile yields the actual oil volume in porous media per unit area adjacent to the well. Three‐phase fluid distributions are predicted using a scaling procedure which requires knowledge of two‐phase air‐water saturation‐pressure relations, hydrocarbon density, and hydrocarbon surface tension. Air‐water saturation‐pressure relations are parameterized by either the Brooks‐Corey or van Genuchten expressions. Parameters in the models are estimated from grain‐size distribution data for two hypothetical soils.

Results reveal that whereas the distance above an oil‐water table at which oil saturations become zero may be independent of soil type, estimated light nonaqueous phase liquid (LNAPL) volumes per unit area may differ substantially. Hence, estimates of LNAPL volume cannot be inferred directly from soil LNAPL thickness or well LNAPL thickness data without consideration of effects of soil properties. Furthermore, it is demonstrated that no simple linear conversion scheme can be employed to relate the height of LNAPL in a monitoring well to the LNAPL volume in porous media. Effects of grain‐size distribution and well LNAPL thickness on the ratio of actual LNAPL thickness in the aquifer to well LNAPL thickness are shown.
Well‐Purging Criteria for Sampling Purgeable Organic Compounds
Authors: Gibs Jacob , Lmbrigiotta Thomas E.
Published: August 2005

Ground‐water‐sampling protocols generally recommend that a well be purged prior to sampling. This recommendation is based on the assumption that the water quality of the water standing in the casing is not the same as that in the aquifer. Three criteria that have been used to determine when a well has been purged sufficiently to yield “representative” water‐quality samples are (1) flushing an arbitrary number of casing volumes, usually a minimum of three, (2) flushing the well until field water‐quality characteristics‐temperature, pH, specific conductance, and dissolved oxygen‐in the purge water are stable, and (3) flushing until hydraulic equilibrium between casing water and aquifer water is achieved. The primary purpose of this study was to evaluate the effectiveness of these criteria in sampling for purgeable organic compounds.

Wells, screened in unconsolidated sand and gravel aquifers at six sites, were sampled during a total of 10 purgings. The discharge from each well and the field characteristics were monitored as a function of time and number of casing volumes flushed. Grab samples for purge‐able organic compounds, chloride, and ultraviolet absorbance at 254 nanometers wavelength‐a gross indicator of the presence of aromatic organic compounds‐were taken each time a set of field measurements was taken. The variation of field characteristics, purgeable organic compounds, chloride, and ultraviolet absorbance at 254 nanometers was compared with time and number of casing volumes flushed.

The results indicate that (1) purgeable organic compound concentrations sbailized when three casing volumes were purged in only 55 percent of the cases evaluated in this study, (2) purgeable organic compounds concentrations did not consistently follow the temporal variation of, nor stabilize at the same time as, the measured field characteristics, and (3) purging to achieve hydraulic equilibrium between casing and aquifer water consistently underestimated the time and casing volumes needed to achieve stable values of water‐quality measurements in highly transmissive aquifers. The conclusion from these data is that none of the previously recommended criteria for purging a well can be applied reliably to collecting a “representative” sample of purgeable organic compounds. These results indicate that the criteria for purging a well prior to sampling for purgeable organic compounds must take into account other factors, such as the unique hydrogeologic characteristics of a site, the nature and extent of purgeable organic compounds present, the areal extent of the contamination, the well construction, and the sampling objectives of the investigation.
A Compatible Single‐Phase/Two‐Phase Numerical Model: 1. Modeling the Transient Salt‐Water/Fresh‐Water Interface Motion
Authors: Ledoux Emmanuel , Sauvagnac Serge , Rivera Alfonso
Published: August 2005

Abstract A numerical model (NEWVAR) to simulate the transient movement of a discrete interface between salt water and fresh water has been developed. NEWVAR is designed to allow the analysis of a regional two‐dimensional ground‐water flow in coastal aquifers. The numerical solution permits the prediction of both regional fresh‐water levels and two‐dimensional fresh‐water/salt‐water interface by using nested square meshes.

The numerical solution is based on the finite‐difference method; the Gauss‐Jordan direct method is used for solving steady‐ and unsteady‐state linear equations. Different procedures are used to avoid numerical difficulties in the transient position of the interface toe for two‐dimensional areal flow.

The numerical solution was tested against the analytical ones for the cases of an advancing interface and of a floating fresh‐water lens over sea water. These tests showed good agreement, thus verifying the finite‐difference approximation. The results of an application of this model to a real aquifer are discussed in a companion paper entitled: “A Compatible Single‐Phase/Two‐Phase Numerical Model 2. Application to a Coastal Aquifer in Mexico.”
Evaluation of Methods for Determining the Vertical Distribution of Hydraulic Conductivity
Authors: Taylor Kendrick , Wheatcraft Stephen , Hess John , Hayworth Joel , Molz Fred
Published: August 2005

Six borehole methods for determining the vertical distribution of hydraulic conductivity in unconsolidated geologic formations are evaluated. Straddle packer tests are inappropriate if there is a hydraulic path around the packer on the outside of the well screen. Methods based on grain‐size analysis fail to incorporate the influence of small‐scale structure and packing. Methods based on relationships between electrical and hydraulic conductivity require special conditions and are site‐ and formation‐specific. Borehole effects invalidate methods based on the natural flow of fluid through a well bore. Stoneley wave attenuation methods are not effective in unconsolidated formations. A single‐well electrical tracer test is effective, but requires the injection of significant volumes of fluid.
ANALYSIS OF AQUIFER TESTS CONDUCTED IN FRACTURED ROCK: A REVIEW OF THE PHYSICAL BACKGROUND AND THE DESIGN OF A COMPUTER PROGRAM FOR GENERATING TYPE CURVES
Authors: Novakowski Kent S.
Published: August 2005

Abstract. Assessing the hydrogeological character of fractured bedrock between two or more wells is usually accomplished through an analysis of the results of traditional pumping tests. Because these tests are subject to field boundary conditions that may be different from those conducted in porous media, alternative testing techniques or analytical methods are required. To provide an adaptable interpretive package for analyzing interwell hydraulic tests in fractured rock, a FORTRAN program was developed to generate type curves for pumping tests and pulse interference tests. A review of the physical conditions which most influence the results of these tests is conducted to provide the background for the development and use of the program. The analytical solutions included in the program consider inner boundary conditions such as wellbore storage, infinitesimally thin skin and finite‐thickness skin. In addition, a solution is included to analyze results influenced by wellbore storage and infinitesimally thin skin at both the pumping and observation wells. The solutions are given in the Laplace domain and are numerically inverted to generate data for the type curves. The curves can be plotted using any standard plotting program, or they can be plotted manually. The program is menu driven, easily adaptable to include additional solutions, and can be executed on a personal computer.
AUTOMATED ANALYSIS OF PUMPING TESTS IN UNCONFINED AQUIFERS OF SEMI‐INFINITE THICKNESS
Authors: Sayed Shabbir A. S.
Published: August 2005

Abstract A procedure is described for automated fitting of test data for pumping from an unconfined aquifer of semi‐infinite thickness. The fitting is achieved by sensitivity analysis and the least‐squares method. The early time data are fitted to the Streltsova (1974) model and the late time data are matched to the Dagan (1967) model. These solutions are useful where the aquifer thickness is extensive and unknown. Data from a test in the Indus Basin, Pakistan, was analyzed to test this procedure.
Investigation by DC Resistivity Methods of a Ground‐Water Barrier Beneath the San Bernardino Valley, Southern California
Authors: Park Stephen K. , Lambert Douglas W. , Lee Tien‐Chang
Published: August 2005

DC resistivity methods were used to confirm the existence of the Bryn Mawr fault and to evaluate its efficacy as a barrier to ground water in the Bunker Hill basin beneath the San Bernardino valley, California. Vertical electrical sounding indicates layering and vertical offsets across the fault. Dipole‐dipole measurements located the fault and determined its attitude. Our modeling indicates that the fault gouge has decreasing resistivity with depth. The resistivity trend is likely caused by increasing clay content. If the interpretation is correct, the ability of the fault to impede ground‐water flow will increase with declining water levels. This theory is supported by greater offset of water levels across the fault when the levels were deeper. DC resistivity methods independently yield models which are consistent with known hydrogeological conditions, and can be used to predict them.
Aquifer Parameters from a One‐Dimensional Steady‐Leaky Type Curve
Authors: Motz Louis H.
Published: August 2005

A drain function and type curve were defined for the one‐dimensional steady‐state leaky aquifer case, and a match‐point procedure was developed for determining the aquifer parameters of transmissivity and leakance. Values for these parameters can be determined by plotting steady‐state values of drawdown versus distance and matching the distance‐drawdown data to the steady‐leaky type curve. The procedure is illustrated by an example that utilizes field data from a canal pumping test in the Tampa, Florida area. Values of transmissivity = 164,000 ft2/day and leakance = 4.9 X 10‐3 day‐1 were determined for the Upper Floridan aquifer from distance‐drawdown and canal flowrate data. These values compare favorably with values of transmissivity and leakance determined from pumping tests and a digital model study in the same area.
Estimating the Precision of Ground‐Water Elevation Data
Authors: Gibbons Robert D.
Published: August 2005

1. Abstract

A common problem in ground‐water monitoring and hydrogeology in general is determining the precision with which to plot ground‐water elevation contours. If ground water represented a completely static system and could be measured without error, the choice would simply be a function of the ambition of the graphic artist or the capabilities of the available computer algorithm. Since contour maps involve an interpolation from a set of irregularly spaced points (i.e., wells or piezometers) to a grid or mesh of evenly spaced points, which in general contains far more points or “nodes” than the original dataset, virtually any level of “graphical precision” is possible (e.g., one‐tenth of a foot). However, ground‐water elevation measurements represent the results of a dynamic process that, in general, does not affect all wells equally. Furthermore, as in any measuring process in which humans are involved, errors of measurement must certainly exist. The natural consequence, of course, is that one component of the total variation in ground‐water elevation data represents random sampling fluctuations. The magnitude of these random sampling fluctuations can in turn be used to make probabilistic statements regarding the precision of ground‐water elevation data such that ground‐water elevation contours may be determined at meaningful intervals.

The importance of empirically determining ground‐water elevation precision is that it assures us that the plotting interval will never be less than the precision of the generating ground‐water elevation data. Without this assurance, which of course is the typical case in practice, structure and even gradients that are observed in a contour plot may be nothing more than the effects of random sampling variability.
A Study of Acid Mine Drainage Using Earth Resistivity Measurements
Authors: Ebraheem A. M. , Hamburger M. W. , Bayless E. R. , Krothe N. C.
Published: August 2005

A resistivity survey was conducted in a reclaimed mine spoils disposal site near Wheatland, Indiana to study the ground‐water contamination. Due to the high conductivity of the acidic leachate from coal refuse, it was possible to detect the valleys in which this material was dumped (gob valleys) by using the horizontal resistivity profiling technique. The thickness of the gob valleys and information about the stratigraphy of the site were obtained by using the vertical electrical sounding (VES) technique. The VES data for sounding points located near monitoring wells, together with the chemical analyses of water samples taken from these wells, were used to obtain an empirical relationship between the inferred earth resistivity and the amount of Total Dissolved Solids (TDS) in the ground water. The horizontal resistivity profiling data and the VES data at a 30‐ft electrode spacing were contoured. The resulting isoresistivity map, together with the empirical relationship, can be used to predict the approximate TDS concentration at a depth of approximately 30 ft at any point on the Wheatland site.
Survey of Microbial Populations in Buried‐Valley Aquifer Sediments from Northeastern Kansas
Authors: Sinclair James L. , Randtke Stephen J. , Denne Jane E. , Hathaway Lawrence R. , Ghiorse William C.
Published: August 2005

Twenty‐two aseptically collected sediment core samples were obtained from below the water table (60 to 280 feet deep) at four pristine sites along a major buried‐valley aquifer system in northeastern Kansas. Samples were examined for total numbers of bacteria, viable aerobic bacteria, protozoa, and fungi. Contiguous samples were obtained in some transition zones of sediment texture or color in order to detect possible population shifts over small vertical distances related to changes in sediment characteristics. Total counts of bacteria varied between 106 and 108 per gram of dry sediment. Viable bacterial counts varied between 0 and 108 colony forming units per gram, usually being higher in sandy or gravelly sediments than in silty or clayey sediments. The relationship between sediment texture and microbial population density was confirmed statistically. Total numbers of bacteria correlated highly with variations in sediment sand and clay content. The population densities of viable bacteria and protozoa correlated moderately with these indicators of sediment texture. In some samples, populations of viable bacteria approached the total count of bacteria and the diversity of bacterial colony types appraoched that found in surface soil. Protozoa were found at low population densities in the coarser textured samples. The protozoa were similar to types commonly encountered in surface soil. No actinomycetes, fungi, or algae were detected in any samples.
Estimation of Leak Rates from Underground Storage Tanks
Authors: Levy Benjamin S. , Riordan Peter J. , Schreiber Robert P.
Published: August 2005

A methodology for estimating the rate and volume of leakage from an underground storage tank (UST) is presented; by estimating leak rate and volume, the leak duration may be calculated. This is accomplished by measuring liquid hydrocarbon thickness upon the water table at two or more monitoring wells located at differing distances from the leaking UST. The methodology is based on Hantush (1967, 1968) and uses type‐curve fitting. Two solutions are developed: one for the case of a flat, rigid water table, and another for the case of a deflected water table. These solutions provide upper and lower estimates for leak rate and duration. The use of the technique is demonstrated by its application to a field case. The technique is best applied to sites with medium‐ to coarse‐grained sands and gravels with minimal capillary effects; application of the technique to sites of fine‐grained porous media may produce unreasonable results.