bluuebunny/crossref_metadata_2025 huggingface dataset:
Indigenous soil and water conservation: A review of the state of knowledge and prospects for building on traditions
Authors: Critchley W. R. S. , Reij C. , Willcocks T. J.
Published: February 2007

After half a century of failed soil and water conservation projects in tropical developing countries, technical specialists and policy makers are reconsidering their strategy. It is increasingly recognised that the land users have valuable environmental knowledge themselves. This review explores two hypotheses: first, that much can be learned from previously ignored indigenous soil and water conservation (ISWC) practices; second, that ISWC can often act as a suitable starting point for the development of technologies and programmes. However, information on ISWC is patchy and scattered. Many ancient, derelict systems are better described than traditions which still persist today. ISWC has been most commonly developed under dry and marginal conditions, and/or on steep hillsides. Sustained population pressure has often tended to stimulate ISWC. There is a need for more incorporation of ISWC into resource conservation programmes: many projects have ignored local traditions to their detriment. It is widely agreed that further study and research on ISWC is required and justified as a logical starting point towards developing adoptable and sustainable soil and water conservation systems for small‐scale farmers.
Nature, extent and severity of soil erosion in upland Scotland
Authors: Grieve I. C. , Davidson D. A. , Gordon J. E.
Published: February 2007

This paper examines the nature, extent and severity of soil erosion in upland Scotland, an area subject to land management pressures typical of temperate maritime uplands. Erosion features were classified and their area measured from aerial photographs. Some 12 per cent of the upland area sampled was subject to some form of erosion, which is very similar to the percentage for Europe as a whole. The most significant erosion category was peat erosion, with 6 per cent of the area being affected; a figure which increased to 20 per cent in one sub‐region. Peat erosion varied in severity, with the most severe erosion being in areas of eastern Scotland with the greatest land management pressures. Gully erosion of slopes on mineral soils was found in almost 5 per cent of the area sampled, particularly in sub‐regions with large amplitude of relief. Debris flow/cone features and screes were less extensive and largely found at higher altitudes. Footpath erosion was mapped in popular mountain areas, but overall the mean length of eroded footpaths was less than that of large gullies. There was little evidence of spatial linkages between erosion of mineral soils and land management at the scale of the survey. Separating the roles of upland management and extreme rainfall events in the inception of erosion remains a key issue in the study of accelerated erosion in temperate maritime upland areas. Some guidance for management is presented.
Erosion and soil productivity in Australia and New Zealand
Authors: Dregne H. E.
Published: February 2007

Soil erosion assumes a different form in Australia and New Zealand. Sheet, rill and gully erosion are common in eastern Australia and wind erosion in the dry cropland areas. In New Zealand, mass movement dominates the erosion landscape but other kinds, including wind erosion, do occur. It is unclear how much of the mass movement is a natural phenomenon and how much is human‐induced. In either case, it causes long‐term reductions in soil productivity. A landmark analysis of the soil productivity loss due to land degradation was conducted by the Australian state of New South Wales. Water erosion was a greater problem than wind erosion, but soil structure deterioration was more costly than either kind of erosion.
Human activities and their impact on land degradation ‐ psilorites mountain in crete: A historical perspective
Authors: Lyrintzis G. , Papanastasis V.
Published: February 2007

Information ins presented on use of the natural resources of the Psilorites mountain in Crete throughour successive historical periods. The dominant human activities are described and their impact on hydrology, flora and fauna is analysed in an attempt to understand the land degradation processes on this Mediterranean mountain.
Soil degradation in the tropical lowlands of Santa Cruz, Eastern Bolivia
Authors: Barber R. G.
Published: February 2007

This paper examines the soil degradation processes that are threatening the productivity of the mechanized annual cropping areas in the Santa Cruz lowlands of tropical eastern Bolivia. The dominant process is that of machinery‐induced and natural compaction, which has resulted in an estimated 50 per cent of the soils in the Central Zone being moderately to severely compacted, causing serious root restriction and the loss of both transmission and water‐storage pores. Degradation has made the soils increasingly susceptible to moisture stress due to the combined effect of (i) restricted rooting as a result of compaction and the hardsetting characteristics of the soils, (ii) reduced rainfall infiltration due to the loss of transmission pores and surface crusting, and (iii) a decrease in available soil moisture caused by the loss of storage pores, the incorporation of wind‐blown fine sand deposits, and soil organic matter losses due to accelerated decomposition rates. The loss of transmission pores has also made the soils more prone to waterlogging in periods of high rainfall. The degradation tendencies of these soils are exacerbated by the greater variability of seasonal rainfall during the last 20 years that has led to a greater frequency or extremely high or extremely low rainfall events than hitherto.
Reclamation of degraded cocoa lands using Albizia Zygia
Authors: Anim‐Kwapong G. J. , Teklehaimanot Z.
Published: February 2007

The structure of the population of Albizia zygia and the regeneration potential of the species from seed were studied in three site conditions (mature cocoa stand, fallow and intact natural forest) in the moist semi‐deciduous forest zone in Ghana. The potential of the species to regenerate vegetatively was also assessed. Different population structures and different natural regeneration status were observed for each site. Regeneration from seed appeared to be of a little importance in the fallow site, whereas vegetative regeneration was found to be a major mechanism of secondary succession in abandoned cocoa farms. The population of Albizia zygia in the forest appeared to be stable, while in the mature cocoa fields it was in decline.

Efficient seed pretreatment techniques and vegetative propagation methods using juvenile cuttings, which are useful for enhanced management of the species, are also presented.

Management strategies using the species for the rehabilitation of degraded cocoa farms are discussed.
Influence of mineral fertilizers and different soil types on nutrient leaching: Results of lysimeter studies in East Germany
Authors: Meissner R. , Rupp H. , Seeger J. , Schonert P.
Published: February 2007

A lysimeter experiment on mineral fertilizer use and soil type was begun in 1985 to study the interrelationships between the level of mineral fertilization and the leaching of nutrients. Increased application of mineral fertilizers brought about not only a significant reduction in effluence build‐up, but also a significant increase in yield. The lowest levels of nitrogen leaching were found in clay‐sand soil in use as grassland, and the highest in sandy soil used as arable land. Unexpectedly, the study was unable to prove statistically that a reduction in N, P and K leaching follows automatically from a reduction in mineral fertilization. Hence, suboptimal fertilization cannot be the only corrective measure if a noticeable or marked reduction in the adverse impact on water quality due to nutrient leaching is to be achieved. Interim plantings should be integrated in crop rotations. Agricultural crops must be siteadapted and suited to the fertilization regime.
Gully erosion associated with the expansion of unterraced almond cultivation in the coastal Sierra de Lujar, S. Spain
Authors: Faulkner H.
Published: February 2007

Since Moorish times, the lower slopes of the Sierra de Lujar in southern Spain have been intensively cultivated. Despite steep slopes and the highly erodible nature of the local micaschist/quartzite bedrock and derivative Quaternary sequences, accelerated erosion has largely been contained throughout this history by substantial, well‐maintained rock terraces. However, since 1987, European Union (EU) agricultural policy has been to encourage the cultivation of certain crops by subsidising their expanded cultivation on a ‘per hectare’ basis. This has resulted in hasty clearance of native Mediterranean matorral on sites really unsuitable for the local staple crop (almonds), and erosion‐prevention terraces are often absent or rudimentary. Gullying is now a very serious problem on some of these newly cleared sites.

This paper identifies the lithological, topographic and agricultural policy controls on the consequent gully distribution, and then explores the pedological and hydrological controls on gully initiation on a single unterraced slope. Using these results alongside morphological data from gully surveys, a gully initiation and growth model is presented. This suggests that two types of gully are present in the area. ‘Type 1’ or upper‐slope gullies are initiated by overland flows, which are relatively infrequent. By contrast, ‘type 2’ or slope‐base gully initiation involves saturation and collapse in fossil landslip scars in Holocene colluvium. These two very different morphological systems may integrate through the terminal fan of the upslope gullies, in a manner described by Tiexeira de Oliveira 1990. The implications of this are that in the study area, sediment removal is associated with a very few highly productive sites. Contemporary management is briefly assessed against this model of geomorphic change in the area.
Agroforestry developments and potential in the Brazilian Amazon
Authors: Smith N. J. H. , Fik T. J. , Alvim P. de T. , Falesi I. C. , SerrãO E. A. S.
Published: February 2007

Much attention in the media and scientific literature has focused on the destruction of tropical forests in Amazonia since the early 1970s, especially in the Brazilian states of Rondǒnia, Acre, Paré and Mato Grosso. Concern is mounting that the peeling back of the forests is wiping out biodiversity, destroying soil resources, possibly exacerbating global warming, and provoking land conflicts, among other socioeconomic and ecological problems. Yet little regard has been paid to some of the promising agricultural developments in the region that are helping to counteract pressures on the remaining forest while recuperating debilitated areas. In particular, a pronounced trend towards planting a mix of tree crops on small farms throughout the basin augers well for the future of the rainforest and more sustainable agriculture. Agroforestry developments in Amazonia underscore the linkages between conserving biodiversity and more productive and resilient agricultural systems.
Pricing bridges to cross a river
Authors: Bouhtou Mustapha , Grigoriev Alexander , Hoesel Stan van , van der Kraaij Anton F. , Spieksma Frits C.R. , Uetz Marc
Published: February 2007

We consider a pricing problem in directed, uncapacitated networks. Tariffs must be defined by an operator, the leader, for a subset of m arcs, the tariff arcs. Costs of all other arcs in the network are assumed to be given. There are n clients, the followers, and after the tariffs have been determined, the clients route their demands independent of each other on paths with minimal total cost. The problem is to find tariffs that maximize the operator's revenue. Motivated by applications in telecommunication networks, we consider a restricted version of this problem, assuming that each client utilizes at most one of the operator's tariff arcs. The problem is equivalent to pricing bridges that clients can use in order to cross a river. We prove that this problem is APX‐hard. Moreover, we analyze the effect of uniform pricing, proving that it yields both an m approximation and a (1 + lnD)‐approximation. Here, D is upper bounded by the total demand of all clients. In addition, we consider the problem under the additional restriction that the operator must not reject any of the clients. We prove that this problem does not admit approximation algorithms with any reasonable performance guarantee, unless P = NP, and we prove the existence of an n‐approximation algorithm. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007
Sudden onset blindness in sickle cell disease due to retinal artery occlusion
Authors: Liem Robert I. , Calamaras Diane M. , Chhabra Manpreet S. , Files Beatrice , Minniti Caterina P. , Thompson Alexis A.
Published: February 2007

Central retinal artery occlusion (CRAO) is a rare and potentially devastating cause of acute blindness in sickle cell disease (SCD) that is unique compared to classic sickle retinopathy. Few details related to this complication in SCD are known, including its risk factors, pathogenesis, presentation, treatment and outcomes. We present three patients with SCD and retinal artery occlusion. The overall variability in clinical presentation, treatment and prognosis reported in the literature underscores the need for a greater understanding of these factors as they relate to this complication in SCD. Pediatr Blood Cancer 2008;50:624–627. © 2007 Wiley‐Liss, Inc.
Treatment of children with diffuse intrinsic brain stem glioma with radiotherapy, vincristine and oral VP‐16: A Children's Oncology Group phase II study
Authors: Korones David N. , Fisher Paul G. , Kretschmar Cynthia , Zhou Tianni , Chen Zhengjia , Kepner James , Freeman Carolyn
Published: February 2007

Background

The prognosis for children with brain stem glioma remains grim. Based on studies suggesting efficacy of vincristine and oral VP‐16, The Pediatric Oncology Group (POG, now part of the Children's Oncology Group) conducted a study using these agents in combination with standard external beam radiation for children with newly diagnosed brain stem glioma.

Methods

Children were eligible for the study if they 3–21 years of age, had MRI‐evidence of a diffuse intrinsic pontine glioma, and had neurologic deficits of <6 months duration. Patients received local radiotherapy to a dosage of 54 Gy. Chemotherapy consisted of two 28‐day cycles of vincristine, 1.5 mg/m2, days 1, 8, and 15 and oral VP‐16, 50 mg/m2, days 1–21, starting concurrent with radiation, and continuing for ten cycles following radiation.

Results

Of the 31 children enrolled, 30 were eligible and evaluable for survival and toxicity. Their median age was 8 years (range 3–14 years). Seven patients (23%) had a partial response following radiation, 18 (60%) had stable disease, 2 (7%) had progressive disease, and response in 3 patients (10%) was not measured. All 30 children have died. Overall survival at 1 year was 27 ± 7% and at 2 years, 3 ± 2%. The median survival was 9 months (range 3–36 months). Hematologic toxicity was significant; other toxicities included constipation, mucositis, emesis, and infection.

Conclusion

The addition of vincristine and oral VP‐16 to standard external beam radiation causes moderate toxicity and does not improve survival of children with diffuse intrinsic brain stem glioma. Pediatr Blood Cancer 2008;50:227–230. © 2007 Wiley‐Liss, Inc.
A retrospective review of hearing in children with retinoblastoma treated with carboplatin‐based chemotherapy
Authors: Lambert Michele P. , Shields Carol , Meadows Anna T.
Published: February 2007

Background

Retinoblastoma occurs in approximately 4 per million children per year in the United States, usually before 2 years of age. In developed countries, 95% of children with tumor in one eye can be cured with enucleation, while children with tumor in both eyes require individualized therapy to preserve vision. Although enucleation and radiation are very effective therapies for children with bilateral disease, the resultant visual impairment, cosmetic deformity and risk for new tumors result in morbidity to these children who otherwise have a near normal lifespan. Therefore, since 1994, chemoreduction with vincristine, carboplatin, and etoposide combined with focal treatment, have been used successfully. However, a major concern with the use of carboplatin has been ototoxicity.

Procedures

To determine whether carboplatin, in the doses and schedule used by us and others to treat retinoblastoma (18.6 mg/kg q 4 weeks for six cycles) results in hearing impairment, we reviewed the records of 248 children with retinoblastoma, 164 of whom had received carboplatin. Children generally received carboplatin, vincristine, and etoposide (CEV) for six cycles of chemotherapy.

Results

Hearing evaluations prior to initiating therapy were abnormal in 14 patients (5.6%). No patients with normal initial audiograms were found to have abnormal studies following repeated evaluations.

Conclusion

While ototoxicity is a potential concern in this young patient population, carboplatin in the treatment of retinoblastoma does not appear to produce impairment. Screening can identify children who require frequent audiologic follow‐up, but children whose hearing is normal prior to therapy do not require routine surveillance following six cycles of standard CEV therapy. Pediatr Blood Cancer 2008;50:223–226. © 2007 Wiley‐Liss, Inc.
Poly(acrylate/epoxy) hybrid adhesives for low‐surface‐energy plastic adhesion
Authors: Sonnenschein Mark F. , Webb Steven P. , Cieslinski Robert C. , Wendt Benjamin L.
Published: February 2007

The formulation, polymerization, and performance of a new class of low‐surface‐energy adhesives for plastics are described. The polymerization involves the simultaneous room‐temperature polymerization of polyoxirane monomers in an acrylic monomer phase. The polymerization of the acrylic phase and adhesion promotion to plastics are catalyzed after the decomplexation and oxidation of trialkylborane–amine complexes. The polymerization of the epoxy phase is catalyzed with a Lewis acid such as BF3, ZnCl2, or SnCl4 complexed with ether or amine. This article explores the resulting adhesives as a function of the epoxy monomer functionality, concentration, solubility in the acrylic monomer, Lewis acid catalyst concentration, phase crosslinking, and postprocessing thermal history. The adhesive morphology exhibits a finely dispersed epoxy phase strongly interacting with the major acrylic phase resulting from a nucleation‐and‐growth phase‐separation mechanism. Excellent adhesion to plastics, including polyethylene, polypropylene, poly(tetrafluoroethylene), poly(ethylene terephthalate), and nylon, is achieved with a much higher thermal performance than that achievable with acrylic polymers alone. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 989–998, 2007
Silicon‐containing benzoxazines and their polymers: Copolymerization and copolymer properties
Authors: Liu Ying‐Ling , Hsu Chih‐Wei , Chou Chin‐I
Published: February 2007

A silicon‐containing benzoxazine BATMS‐Bz (1,3‐bis(3‐aminopropyl)tetramethyldisiloxane‐benzoxazine) was used for polybenzoxazine modification by means of formation of benzoxazine copolymers with 3,4‐dihydro‐3‐phenyl‐2H‐1,3‐benzoxazine (Ph‐Bz) and 3‐furfuryl‐3,4‐dihydro‐2H‐1,3‐benzoxazine (F‐Bz), respectively. Ph‐Bz/BATMS‐Bz copolymers showed a positive deviation due the presence of intermolecular hydrogen bonding. However, this effect was not observed with F‐Bz/BATMS‐Bz copolymers. Meanwhile, BATMS‐Bz incorporation exhibited significant effect on toughening polybenzoxazines. It is therefore demonstrated that BATMS‐Bz is a high performance modifier to simultaneously enhance the Tg and toughness of polybenzoxazines. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1007–1015, 2007
Polymer encapsulation of yttrium oxysulfide phosphorescent particles via miniemulsion polymerization
Authors: Kim Hyungsoo , Daniels Eric S. , Li Shang , Mokkapati Vijaya K. , Kardos Keith
Published: February 2007

Yttrium oxysulfide upconverting phosphor particles can absorb infrared light and emit dopant‐dependent visible phosphorescence. This unique optical property has been used for particle‐based immunoassay applications. In this study, upconverting phosphor particles were encapsulated with a functionalized polymer (carboxylated polystyrene) shell layer via several approaches, which included the following: (1) the physical adsorption of the carboxylated polystyrene polymer onto the phosphor surfaces, (2) the miniemulsification of the preformed carboxylated polystyrene in a solvent in the presence of the phosphor particles and the subsequent stripping off of the solvent, and (3) the miniemulsification and miniemulsion copolymerization of styrene and methacrylic acid in the presence of the phosphor particles with hexadecane as a costabilizer in combination with a surfactant (sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, or sodium dihexyl sulfosuccinate). Miniemulsion technology proved to be the most effective method for forming a functionalized polymeric nanoshell surrounding the phosphor particles. The morphology of the encapsulated phosphor particles was found to vary from symmetric core–shell (i.e., a uniform nanoshell layer with varying shell thicknesses), asymmetric core–shell, dumbbell‐like, or raspberry‐like partial encapsulation to multiparticle encapsulation. The amount of multiparticle encapsulation could be reduced by the postaddition of a surfactant, but it could not be eliminated completely. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1038–1054, 2007
Raft mediated surface grafting of t‐butyl acrylate onto an ethylene–propylene copolymer initiated by gamma radiation
Authors: Kiani Khalid , Hill David J. T. , Rasoul Firas , Whittaker Michael , Rintoul Llewellyn
Published: February 2007

RAFT mediated grafting of poly(t‐butyl acrylate) onto the surface of a commercial poly(ethylene‐co‐propylene), Elpro, has been carried out using initiation by 60Co γ‐radiation at 298 and 273 K. The polymerizations were in bulk monomer and using the RAFT agent 1‐phenylethyl phenyldithioacetate. The rates of homopolymerization and grafting were found to decrease with increasing RAFT agent concentration, indicating that both polymerization processes involve participation of the RAFT agent. There was good agreement between the predicted and experimental molecular weights of the homopolymer that had a narrow polydispersity. The poly(t‐butyl acrylate) grafts were hydrolyzed by trifluoroacetic acid to form poly(acrylic acid) grafts, which could either be further functionalized or used to control the surface polarity of the Elpro. ATR‐FTIR spectroscopy was used to characterize the grafts and Raman spectroscopy was used to assess the depth of the grafts. The water contact angle for the Elpro surface grafted with poly(acrylic acid) was found to be linearly dependent on the amount of the graft present. The living nature of the grafted chains was demonstrated by the addition of a second block of polystyrene. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1074–1083, 2007
Synthesis of hyperbranched polymers with precise conjugation length
Authors: Li Jing , Sun Minghao , Bo Zhishan
Published: February 2007

A set of AB2 type monodisperse conjugated oligomers carrying two bromo functional groups and one boronic ester functional group were prepared by iterative deprotection and Sonogashira cross‐coupling reactions. Suzuki polycondensation of these AB2 type monodisperse oligomers afforded hyperbranched polymers. The hyperbranched conjugated polymers we prepared possess not only precisely controlled conjugation length like monodisperse conjugated oligomers but also the structural feature of hyperbranched polymers. Optical property investigation demonstrated that the maximum absorption and emission wavelength red‐shifted along with the increasing of the conjugation length between the two branching points and the hyperbranched structure could effectively reduce the aggregation of the conjugated polymer chains. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1084–1092, 2007
Spontaneous formation of hierarchical proton‐conductive structures in sulfonated poly(p‐phenylene terephthalamide) copolymer films
Authors: Sisbandini Ciptanti , Every Hayley A. , Viale Sebastien , Mendes Eduardo , Picken Stephen J.
Published: February 2007

Two partially sulfonated copolymers of poly(p‐phenylene terephthalamide) were studied; the sulfonated diamine to nonsulfonated diamine ratios were x = 1 and x = 2. Polymer solutions in water demonstrated lyotropic liquid‐crystalline behavior, with the critical concentration for nematic phase formation being around 0.7 wt %. Films of these copolymers could be considered for fuel‐cell applications. The in‐plane proton conductivities were of the order of 10−3 to 10−2 S cm−1 between 20 and 90 °C. Increasing the sulfonation level resulted in a more conductive material. Spontaneous alignment of the polymer occurred during film formation, as revealed by X‐ray diffraction. Scattering along the polymer backbone was observed perpendicular to the film, implying that the polymer chains were homeotropically aligned with respect to the film. The average degree of alignment was determined to be 0.66 and 0.77 for x = 1 and x = 2, respectively. Evidence of secondary layering within the plane of the film was seen in SEM images. These layers could provide a pathway for proton conduction to occur within the plane of the film. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 666–676, 2007
Three‐dimensional structural analysis of a block copolymer by scanning electron microscopy combined with a focused ion beam
Authors: Kato Mitsuro , Ito Toshihiko , Aoyama Yoshitaka , Sawa Koji , Kaneko Takeshi , Kawase Noboru , Jinnai Hiroshi
Published: February 2007

A three‐dimensional (3D) lamellar structure of a poly(styrene‐block‐isoprene) block copolymer was observed at submicrometer and micrometer levels by scanning electron microscopy combined with a focused ion beam (FIB–SEM). The 3D lamellar structure with an exceptionally large periodicity, about 0.1 μm, was successfully reconstructed, and the size of the reconstructed image by FIB–SEM was 6.0 × 6.0 × 4.0 μm3, which was greater than the transmission electron microtomography data, 3.8 × 3.9 × 0.24 μm3, by a factor of about 40. This result indicates that 3D reconstruction using FIB–SEM is quite useful for direct 3D observations, especially analyses of polymeric materials at the submicrometer and micrometer levels. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 677–683, 2007
Estimating the costs of corrective action at land disposal facilities
Authors: Huffman Larry , Karam Joseph , Bailey Paul
Published: February 2007

The U.S. Environmental Protection Agency (EPA) has proposed regulations that would require corrective action (e.g., soil excavation and groundwater removal and treatment) at municipal solid waste landfills (MSWLFs) and hazardous waste treatment, storage, and disposal facilities (TSDFs). This paper presents an overview of the proposed corrective action regulations, and discusses their relationship to proposed or existing closure and post‐closure care regulations. The paper then presents estimated corrective action cost curves for various MSWLF scenarios defined by landfill area, average waste thickness, and the presence or absence of a clay liner. The paper finally illustrates the economic benefits of sound closure and postclosure care by comparing estimated costs of corrective action to estimated costs of closure and postclosure care at MSWLFs.
The process and potential of bioremediation
Authors: Shorthouse Barry
Published: February 2007

Bioremediation has proven to be a powerful weapon in cleaning up contaminated soils and aquifers. This article gives the perspective of time, cost, and extent of remediation. It warns that disappointment will follow unless adequate site assessments are made and that the support of nutrients and supply of oxygen must be assured. Bioremediation cannot deal with all contaminants and the process is not instantaneous. However, the method is fail safe. In spite of any mistakes we may make, nature will eventually come to our rescue.
Reductive dehalogenation: A subsurface bioremediation process
Authors: Sims Judith L. , Suflita Joseph M. , Russell Hugh H.
Published: February 2007

Introduction and large‐scale production of synthetic halogenated organic chemicals over the last fifty years has resulted in a group of contaminants that tend to persist in the environment and resist both biotic and abiotic degradation. The low solubility of these types of contaminants, along with their toxicity and tendency to accumulate in food chains, make them particularly relevant targets for remediation activities.

Among the mechanisms that result in dehalogenation of some classes of organic contaminants are stimulation of metabolic sequences through introduction of electron donor and acceptor combinations; addition of nutrients to meet the needs of dehalogenating microorganisms; possible use of engineered microorganisms; and use of enzyme systems capable of catalyzing reductive dehalogenation.

The current state of research and development in the area of reductive dehalogenation is discussed along with possible technological application of relevant processes and mechanisms to remediation of soil and groundwater contaminated with chlorinated organics. In addition, an overview of research needs is suggested, which might be of interest for development of in‐situ systems to reduce the mass of halogenated organic contaminants in soil and groundwater.
Petroleum biodegradation in soil: The effect of direct application of surfactants
Authors: Graves Duane , Leavitt Maureen
Published: February 2007

The direct application of surfactants to petroleum‐contaminated soil has been proposed as a mechanism to increase the bioavailability of insoluble compounds. Solubilization of hydrophobic compounds into the aqueous phase appears to be a significant rate limiting factor in petroleum biodegradation in soil. Nonionic surfactants have been developed to solubilize a variety of compounds, thus increasing the desorption of contaminants from the soil. In this study, laboratory scale land treatment scenarios were used to monitor the bioremediation of petroleum contaminated soils. In efforts to achieve the lowest levels of residual petroleum hydrocarbons in the soil following biotreatment, 0.5 and 1.0% (volume/weight) surfactant was blended into soils under treatment. Two soil types were studied, a high clay content soil and a sandy, silty soil. In both cases, the addition of surfactant (Adsee 799®, a blend of ethoxylated fatty acids, Witco Corporation) stimulated biological activity as indicated by increased heterotropbic colony forming units per gram of soil. However, the increased activity was not correlated with removal of petroleum hydrocarbons. The results suggest that the application of surfactants directly to the soil for the purpose of solubilizing hydropbobic compounds was not successful in achieving greater levels of petroleum hydrocarbon removal.
Remediation of sites contaminated with TCE
Authors: Russell Hugh H. , Matthews John E. , Sewell Guy W.
Published: February 2007

Widespread use of trichloroethylene (TCE) in the U.S. has resulted in its frequent detection in soil and groundwater. TCE can become a health hazard after being processed in the human liver; or reductive dehalogenation in the environment may result in production of vinyl chloride, a known carcinogen. This has generated a high degree of interest in efficient and cost‐effective technologies that can be used to remediate soil and ground‐water contaminated with TCE. The purpose of this paper is to present and discuss relevant physicochemical properties and reactive mechanisms of TCE, and to delineate and discuss promising remediation methodologies that have been proposed and/or demonstrated for restoring contaminated subsurface environments. The information in this article has been funded wholly or in part by the U.S. EPA under contract No. 68–C8–0058 to Dynamac Corporation; it has been subjected to the Agency's peer and administrative review process and approved for publication.
The proposed RCRA corrective action rule and its effect on remediation technologies
Authors: Simon John A.
Published: February 2007

The U.S. Environmental Protection Agency (EPA) published the Proposed Rule for Corrective Action for Solid Waste Management Units at Hazardous Waste Management Facilities in the July 27, 1990 Federal Register. The proposed rule sets forth mechanisms for implementing corrective actions under the Resource Conservation and Recovery Act of 1976 (RCRA). To date, the EPA has had the authority to require corrective actions at hazardous waste facilities, but has not had a defined framework to follow when requiring corrective actions. The proposed rule identifies when corrective actions are necessary, procedures to follow when developing corrective measure studies for corrective actions, and methods for implementing corrective actions.

This article focuses on the effect the proposed rule will have on the development and implementation of remediation technologies. It provides not an in‐depth interpretation of the proposed rule, but an analysis of the overall value of its framework for selecting remedial alternatives and the proposed action levels that are likely to drive cleanups. The article begins by presenting a brief background of the proposed rule, including how the rule fits into the overall RCRA regulation and what the major points of interest in the rule are. The article then discusses how corrective measure studies are to be performed. The development and the importance of the action levels in the proposed rule are also presented. This is followed by a description of EPA's regulatory impact analysis of the proposed rule.
Mobile infrared incineration of PCB‐contaminated soils
Authors: Hay George H. , McCartney Gregory J.
Published: February 2007

OHM owns and operates a mobile infrared thermal destruction unit (TDU) that is capable of effective, on‐site remediation of TSCA and RCRA contaminants. The TDU has demonstrated a destruction and removal efficiency (DRE) of 99.9999 percent for PCBs. The unit has undergone extensive testing and holds a National TSCA Permit in the United States and a Federal Permit in Canada for the treatment of PCB‐contaminated materials.

This article discusses the introduction of the TDU to the industry, and also provides a description of the TDU process, past thermal destruction projects, and TDU performance data.
Incineration treatment of arsenic‐contaminated soil
Authors: Waterland Larry R. , King Charly , Richards Marta K. , Thurnau Robert C.
Published: February 2007

An incineration test program was conducted at the U.S. Environmental Protection Agency's Incineration Research Facility to evaluate the potential of incineration as a treatment option for contaminated soils at the Baird and McGuire Superfund site in Holbrook, Massachusetts. The purpose of these tests was to evaluate the incinerability of these soils in terms of the fate of arsenic and lead and the destruction of organic contaminants during the incineration process. The test program consisted of a series of bench‐scale experiments with a muffle furnace and a series of incineration tests in a pilot‐scale rotary kiln incinerator system.

The study reported in this paper was funded by the Environmental Protection Agency under Contract 68–C9–0038 to Acurex Corporation. It has been subjected to the Agency's review and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
Developing incineration process designs and remediation projects from treatability studies
Authors: Tillman David A. , Seeker W. Randall , Pershing David W. , DiAntonio Katherine
Published: February 2007

The Bog Creek Farm CERCLA (Superfund) site in Howell Township, New Jersey, was extensively contaminated, allegedly with wastes from paint manufacturing. The site contained two types of incinerable wastes: contaminated soils and sediments. A remedial investigation and feasibility study (RI/FS) was conducted, leading to a recommendation to treat the most contaminated areas by incineration. This recommendation was converted into the selected approach through the Record of Decision (ROD) mechanism. Contaminants at the Bog Creek Farm site included a wide range of volatiles, semivolatiles, and heavy metals. The incineration approach chosen, therefore, had to remove the organics from the soil without creating additional problems associated with heavy metals emissions. In order to evaluate the incineration problem and develop an advisory conceptual design for its solution, Ebasco Services Incorporated performed extensive characterizations of the material. Such characterizations included performing proximate and ultimate analyses and determining other key physical, chemical, and thermodynamic properties of the soils and sludges.

Energy and Environmental Research Corporation (EER) then performed treatability studies in its rotary kiln test incinerator. These treatability studies focused upon the rotary kiln, and the environment required for cleaning the soil. They assumed that contaminants in the vapor phase could be destroyed in the afterburner. Tests were conducted at bed temperatures of 1,000°F, 1,460°F, and 1,800°F. Samples were drawn from the kiln at intermediate times. Combustion regimes were therefore constructed for the treatment of Bog Creek Farm wastes, maximizing organic removal while managing the heavy metals problem.

Ebasco then converted the results of the incinerability or treatability studies into an advisory conceptual design. This advisory conceptual design called for a kiln temperature of 1,600°F (bed temperature of 1,200°F) and a solids residence time in the kiln of 40 minutes. Additional data indicated that the afterburner could operate at 1,800°F in order to ensure destruction of the POHCs. Combustion chemistry fundamentals demonstrated that the minimum afterburner temperature required was 1,650°F. Ebasco converted this conceptual design into a performance specification to be used in the bid process, under the management of the U.S. Army Corps of Engineers. The remediation was then put out to bid. Chemical Waste Management was the successful bidder. The incineration was successfully completed by August 1990; the system was then demobilized, as the site was remediated.
Bioremediation of PCP‐contaminated soil: Bench to full‐scale implementation
Authors: Mahaffey William R. , Sanford Robert A.
Published: February 2007

Pentachlorophenol (PCP) is a widely used wood treatment agent and pesticide that is often listed among the contaminants at hazardous waste sites. Bench‐scale studies were performed to develop a microbial culture and biodegradative process that could treat PCP at higher concentrations than previously reported. Several substrate formulations and culture techniques were evaluated. Ultimately a “self‐feeding” (pH auxostat) continuous culture system (pH auxostat) was used to select for biodegradative activity with PCP as the carbon and energy source. After a period of 50 days, influent PCP concentrations reached 3,500 mg/liter at a dilution rate of 0.066 H−1. Of the total theoretical chloride that could be released from PCP, 99% was detected as free chloride in the reactor effluent. PCP analysis of the effluent verified complete degradation by the microbial consortium. The reactor was converted to a constant PCP feed. At steady state conditions, the dilution rate was 0.05 H−1 with an influent PCP concentration of 2,560 mg/liter and a biomass yield of 018 mg (dry weight) per mg of PCP. Mineralization studies performed with the microbial consortium using [U‐14C1]‐PCP indicated that 36.5% of the label was released as 14C‐carbon dioxide.
Cost estimating of the closure/post‐closure phase
Authors: Cressman Kenneth R.
Published: February 2007

The U.S. Department of Energy (DOE) is beginning major environmental restoration projects of both active and inactive sites throughout the United States. The problems at the sites include contaminated soils, groundwater and surface waters, structures, and old waste disposal areas.

IT Corporation, under the direction of the Office of Independent Cost Estimating (OICE) for DOE, developed a list of environmental problems at the sites and probable cleanup technologies and techniques that could be used. Estimated unit costs were then developed for these cleanup technologies, using available data and references.

Some procedures developed were common to many or all cleanup projects. These included site characterization, remedial investigation (RI), feasibility studies (FS), and the closure/post‐closure phase. The article will focus on cost estimating of the closure/post‐closure phase of a cleanup project. The cost data provided are for budget level or check estimates. Site‐specific conditions as well as items peculiar to the environmental industry, such as governmental regulations and community relations, can influence both the cost and duration of a cleanup project.
Successful UV/oxidation of VOC‐contaminated groundwater
Authors: Fletcher David B.
Published: February 2007

Ultraviolet light/oxidation has proven its effectiveness in destroying volatile organic chemicals (VOCs) found in groundwater during a U.S. Environmental Protection Agency (EPA) field study. Under the Superfund Innovative Technology Evaluation (SITE) program, PRC Environmental Management, Inc., and EPA monitored the performance of a system employing advanced oxidation techniques at the Lorentz Barrel & Drum (LB&D) Superfund site in San Jose, California.

The firm of Ultrox International (Santa Ana, CA) demonstrated its technology for combining ultraviolet light, hydrogen peroxide and ozone to oxidize toxic organic chemicals found in water. All evaluation criteria were successfully met in the study's results. Greater than 90% of the VOCs were removed. The applicable discharge standards (National Pollution Discharge Elimination System) were attained, and there were no emissions.
Effective low‐temperature thermal aeration of soils
Authors: Bell Brian M. , Giese Raymond G.
Published: February 2007

Low‐temperature thermal aeration (LTTA) is a remedial technology developed by Canonie Environmental Services Corp. (Canonie) for use on soils containing nonchlorinated hydrocarbons, chlorinated solvents, volatile organic compounds (VOCs), chlorinated pesticides, and low levels of polynuclear aromatic hydrocarbons (PAHs). The LTTA system separates these hazardous constituents from excavated soils and allows the treated soils to be redeposited on‐site without restriction.

This article describes the various components and operation of LTTA systems for the remediation of soils contaminated with chlorinated and nonchlorinated constituents. The article also details the results of projects completed to date, principally for soil impacted with chlorinated hydrocarbons, and discusses the general characteristics and results of systems used for soils contaminated with nonchlorinated hydrocarbons (gasoline, etc.).
State‐of‐the‐art VOC abatement from soil‐venting operations
Authors: Buck F. A. M. , Seider E. L.
Published: February 2007

The development of treatment technologies to limit the discharge of volatile organic compounds (VOCs) into the atmosphere has proceeded apace with the increasing use of soil venting for the remediation of contaminated soil. This article surveys the commonly‐used emission control systems that have developed under air pollution control regulations in California. Emphasis is on equipment operating characteristics, typical performance results (destruction efficiencies of VOCs), and operating costs. A recently commercialized process for treating halogen‐containing VOCs is described, and some operating and cost data are included.
Remediating groundwater using a hydraulic containment system for pump and treat
Authors: Harrod Peter E.
Published: February 2007

Twenty years of waste disposal operations at the Conservation Chemical Company (CCC) site in Kansas City, Missouri, led to contamination of soils and groundwater on a six‐acre site. As a result of this contamination, the site was listed on the federal government's National Priorities List.

Following extensive litigation initiated in 1982, more than 200 contributors to the site (Potentially Responsive Parties or PRPs), CCC's insurance companies, and the government ultimately reached a settlement to fund the remedial action. The remedy that was agreed upon included: (1) a permeable cap to allow water intrusion to assist groundwater cleanup; (2) a with drawal well system to achieve an inward groundwater gradient; and (3) a groundwater treatment system employing several unit operations. Containment of the contaminated plume relied on hydraulic, rather than structural, containment to prevent mitigation of contaminants from the site. ABB Environmental Services, Inc. (ABB‐ES) was retained to perform treatability tests and to design, construct, and start up the groundwater treatment plant after the installation of the permeable cap by others.
How to negotiate remediation projects with regulatory agencies
Authors: Evans Louis A.
Published: February 2007

The news that a company has been identified as a potentially responsible party (PRP) at a federal or state Superfund site usually sends a current of fear through the company's management. Even executives with experience in Superfund projects foresee a lengthy, complicated process that involves enormous expenditures and a possible public relations disaster. The author argues, however, that the Superfund process can be managed in a cost‐effective way, prevent reactive responses, inaction, and ineffective action, and applying the business acumen that enabled the company to prosper in the first place. This article explores a critical aspect of the remediation process—negotiation of settlements with regulatory agencies (EPA or a state department of environmental protection)—and details the practical steps needed to conduct those negotiations. It also describes common mistakes that can be avoided. For brevity and clarity, it is assumed that the company in question is the only PRP that has received a notice letter from the regulatory agency.
Removing gasoline from soil and groundwater through air sparging
Authors: Marley Michael C.
Published: February 2007

Although a soil vapor extraction system (SVES) had effectively remediated the vadose zone soils at a gasoline spill site in Pawtucket, Rhode Island, gasoline remained in the soils below the water table. The state Department of Environmental Management (DEM) closure criteria of 10,000 parts per billion (ppb) were still not met after five years. This article describes how an air sparging system was added to the effort for $57,000, and how after three weeks, closure criteria were achieved.
Two granular‐activated carbons for adsorbing army explosives
Authors: Dennis Ronald M. , Lowe William L. , Wujcik Walter J.
Published: February 2007

Explosives‐contaminated groundwater percolating from storage ponds at the Milan Army Ammunition Plant (MAAP) in Milan, Tennessee, into the Claiborne aquifer threatens to contaminate more groundwater—and possibly surface water—in the area. The research described in this article sought to determine whether granular‐activated carbon (GAC) could help remove the explosives from the water and to identify which carbons can adsorb the most TNT, RDX, HMX, Tetryl, and others. Two carbons—Atochem, Inc. GAC 830 and Calgon Filtrasorb 300—were found to be promising candidates. As for what to do with the explosives that would be adsorbed, as well as the contaminated carbon, stay tuned.