bluuebunny/crossref_metadata_2025 huggingface dataset:
A case for formant analysis in forensic speaker identification
Authors: Nolan Francis , Grigoras Catalin
Published: July 2006

Views differ on the relative importance for forensic speaker identification of different aspects of the speech signal. It is argued here that formants, whose frequencies and dynamics are the product of the interaction of an individual vocal tract with the idiosyncratic articulatory gestures needed to achieve linguistically agreed targets, are so central to speaker identity that they must play a pivotal role in speaker identification. As a practical demonstration a case is described in which F1, F2 analysis of a vowel and F2 analysis of three diphthongs show a consistent separation between two recordings, thus effectively eliminating a suspect from having made obscene telephone calls. Subsequent additional analysis, based on the statistical distribution of formant frequency estimates throughout the samples, confirms the distinctness of the voice of the suspect and that of the obscene caller. The theoretical foundation for several kinds of formant-based analysis is then discussed.
Influence of vocal effort on average and variability of fundamental frequency
Authors: Jessen Michael , Koster Olaf , Gfroerer Stefan
Published: July 2006

Read and spontaneous speech was produced by 100 male adult speakers of German in a neutral setting and in a Lombard setting, where 80 dB noise was presented over headphones. Average f0 (‘f0mean’) and relative standard deviation of f0 (‘f0varco’) were determined for each speaker in each of the four conditions spontaneous neutral, spontaneous loud, read neutral and read loud. The results confirm that
when increasing vocal effort from neutral to loud speech, f0mean increases as well.

None of the 100 speakers posed an exception to this effect, but the size of the effect differed between speakers, even after differences in amplitude level were accounted for. F0varco was significantly higher in loud than normal speech for the reading task, whereas in spontaneous speech no significant difference occurred. These results are compared with the literature and discussed with respect to explanations and forensicphonetic implications.
Theoretical modelling of jet grouting
Authors: Modoni G. , Croce P. , Mongiovì L.
Published: July 2006

Theoretical modelling of the mechanical phenomena induced by jet grouting is presented. The analysis is developed for the single-fluid method. The jet propagation across the space included between the injection nozzles and the intact soil is first modelled on the basis of the theory of submerged flows. Different possible interaction modes between jet and soil are then assumed for gravels, sands and clays, according to the results of previous experimental investigations. In the case of gravels, grout seepage is considered to be the most relevant mechanism. For sandy soils, the injected fluid is assumed to penetrate, for a limited extent, into the soil skeleton, producing a considerable increment of the pore pressures and a corresponding reduction of the grain-to-grain contact forces. The removal of the soil particles is then triggered by the dragging action of the fluid threads, and the analysis is developed under drained conditions. For clayey soils, the jet action is considered as a load imposed on the jet-soil interface, and the erosion process is modelled as an evolving sequence of undrained failures. Theoretical results obtained for the different soil types are compared with available experimental data, and the models are thus calibrated by means of back-analysis.
Installation effects of a bored pile wall in overconsolidated clay
Authors: Richards D. J. , Clark J. , Powrie W.
Published: July 2006

In situ embedded retaining walls are used to form basements and cuttings in urban areas throughout the world, particularly where space is restricted. It is generally accepted that the process of installing such a wall may influence the stress state of the soil and hence the post-construction displacements, wall bending moments and prop loads. However, wall installation is a complex three-dimensional problem, and its effects are not well understood. This paper describes a study carried out on a section of contiguous bored pile retaining wall in an overconsolidated clay in Kent, England, using instrumentation to monitor total horizontal stresses and pore water pressures before, during and after wall installation. Reductions in horizontal stress were recorded during wall installation, bringing the ratio of horizontal to vertical effective stress, K, from an initial value of about 1 to about 0·8. Following wall installation there was no further change in horizontal stress over an additional period of 10 months during which no further construction work took place.
A hybrid empirical-mechanistic modeling approach for extrapolating biota–sediment accumulation factors and bioaccumulation factors across species, time, and/or ecosystems
Authors: Burkhard Lawrence P. , Cook Philip M. , Lukasewycz Marta T.
Published: July 2006

An approach is presented for extrapolating field-measured biota–sediment accumulation factors (BSAFs) and bioaccumulation factors (BAFs) across species, time, and/or ecosystems. This approach, called the hybrid bioaccumulation modeling approach, uses mechanistic bioaccumulation models to extrapolate field-measured bioaccumulation data (i.e., BSAFs and BAFs) to new sets of ecological conditions. The hybrid approach predicts relative differences in bioaccumulation using food web models with two sets of ecological conditions and parameters: One set for the ecosystem where the BSAFs and/or BAFs were measured, and the other set for the ecological conditions and parameters for which the extrapolated BSAFs and/or BAFs are desired. The field-measured BSAF (or BAF) is extrapolated by adjusting the measured BSAF (or BAF) by the predicted relative difference, which is derived from two separate solutions of the food web model. Extrapolations of polychlorinated biphenyl BSAFs and BAFs for lake trout (Salvelinus namaycush) from southern Lake Michigan to Green Bay of Lake Michigan (Green Bay, WI, USA) walleye (Stizostedion vitreum) and brown trout (Salmo trutta), as well as Hudson River largemouth bass (Micropterus salmoides) and yellow perch (Perca flavescens), resulted in generally better agreement between measured and predicted BSAFs and BAFs with the hybrid approach.
Dietary accumulation of hexabromocyclododecane diastereoisomers in juvenile rainbow trout (Oncorhynchus mykiss) I: Bioaccumulation parameters and evidence of bioisomerization
Authors: Law Kerri , Palace Vince P. , Halldorson Thor , Danell Robert , Wautier Kerry , Evans Bob , Alaee Mehran , Marvin Chris , Tomy Gregg T.
Published: July 2006

Juvenile rainbow trout (Oncorhynchus mykiss) were exposed to three diastereoisomers (α, β, γ) of hexabromocyclododecane (C12H18Br6) via their diet for 56 d followed by 112 d of untreated food to examine bioaccumulation parameters and test the hypothesis of in vivo bioisomerization. Four groups of 70 fish were used in the study. Three groups were exposed to food fortified with known concentrations of an individual diastereoisomer, while a fourth group were fed unfortified food. Bioaccumulation of the γ-diastereoisomer was linear during the uptake phase, while the α- and β-diastereoisomers were found to increase exponentially with respective doubling times of 8.2 and 17.1 d. Both the β- and the γ-diastereoisomers followed a first-order depuration kinetics with calculated half-lives of 157 ± 71 and 144 ± 60 d (±1 × standard error), respectively. The biomagnification factor (BMF) for the α-diastereoisomer (BMF = 9.2) was two times greater than the β-diastereoisomer (BMF = 4.3); the large BMF for the α-diastereoisomer is consistent with this diastereoisomer dominating higher-trophic-level organisms. Although the BMF of the β-diastereoisomer suggests that it will biomagnify, it is rarely detected in environmental samples because it is present in small quantities in commercial mixtures. Results from these studies also provide evidence of bioisomerization of the β- and γ-diastereoisomers. Most importantly, the α-diastereoisomer that was recalcitrant to bioisomerization by juvenile rainbow trout in this study and known to be the dominant diastereosiomer in fish was bioformed from both the β- and the γ-diastereoisomers. To our knowledge, this is the first report of bioisomerization of a halogenated organic pollutant in biota.
Behavior of B, Cr, Se, As, Pb, Cd, and Mo present in waste leachates generated from combustion residues during the formation of ettringite
Authors: Saikia Nabajyoti , Kato Shigeru , Kojima Toshinori
Published: July 2006

The behavior of B, Cr, Se, As, Pb, Cd, and Mo in the leachates generated from two combustion residues, coal-fired power plant fly ash and municipal solid waste incineration ash, during precipitation of ettringite is presented. Experiments also were performed using modeled waste leachates as well as controlled solutions containing all the investigated elements. Moreover, to determine the possible effect of pH, lime treatment was conducted using the waste and modeled leachates. Results indicated the removal of B, Se, and Cr from the leachates because of incorporation of their oxyanions in the ettringite structure. The removal of B could further be explained by considering the structure of ettringite and monosulfoaluminate. The removal of Pb also occurred, probably because of lime-induced precipitation of Pb(OH)2. Similarly, the removal of As was observed as a result of lime-induced precipitation of Ca3(AsO4)2 and incorporation into the ettringite structure. On the other hand, the precipitation of ettringite did not reduce the concentrations of Mo and Cd because of the complex nature of these elements in the leachates. The results also suggest that the presence of high amounts of constituents such as Cl−, an alkali metal in the solution, also affected ettringite precipitation behavior. Moreover, elemental speciations as well as the presence of other constituents in the solution affected the incorporation by ettringite.
Online reading strategy guidance in a foreign language
Authors: Bouvet Eric , Close Elizabeth
Published: July 2006

This paper reports on an online guided reading program designed and developed by the authors, and implemented in class conditions. The program allows students to read a short story from a computer screen and obtain immediate support, in the form of suggested problem-solving strategies designed to help them overcome the lexical and grammatical difficulties commonly encountered by intermediate language students, at local text level, during the reading process. Based on the analysis of case studies of readers, the chief objective of this study is to gauge the pedagogical relevance of the guided reading program and suggest that it facilitates intermediate language students’ first encounters with literary texts.
Economic Feasibility of No‐Tillage and Manure for Soil Carbon Sequestration in Corn Production in Northeastern Kansas
Authors: Pendell Dustin L. , Williams Jeffery R. , Rice Charles W. , Nelson Richard G. , Boyles Scott B.
Published: July 2006

This study examined the economic potential of no‐tillage versus conventional tillage to sequester soil carbon by using two rates of commercial N fertilizer or beef cattle manure for continuous corn (Zea mays L.) production. Yields, input rates, field operations, and prices from an experiment were used to simulate a distribution of net returns for eight production systems. Carbon release values from direct, embodied, and feedstock energies were estimated for each system, and were used with soil carbon sequestration rates from soil tests to determine the amount of net carbon sequestered by each system. The values of carbon credits that provide an incentive for managers to adopt production systems that sequester carbon at greater rates were derived. No‐till systems had greater annual soil carbon gains, net carbon gains, and net returns than conventional tillage systems. Systems that used beef cattle manure had greater soil carbon gains and net carbon gains, but lower net returns, than systems that used commercial N fertilizer. Carbon credits would be needed to encourage the use of manure‐fertilized cropping systems.
Soil Organic Carbon and Nitrogen Accumulation in Plots of Rhizoma Perennial Peanut and Bahiagrass Grown in Elevated Carbon Dioxide and Temperature
Authors: Allen Leon Hartwell , Albrecht Stephan L. , Boote Kenneth J. , Thomas Jean M. G. , Newman Yoana C. , Skirvin Katherine W.
Published: July 2006

Carbon sequestration in soils might mitigate the increase of carbon dioxide (CO2) in the atmosphere. Two contrasting subtropical perennial forage species, bahiagrass (BG; Paspalum notatum Flügge; C4), and rhizoma perennial peanut (PP; Arachis glabrata Benth.; C3 legume), were grown at Gainesville, Florida, in field soil plots in four temperature zones of four temperature‐gradient greenhouses, two each at CO2 concentrations of 360 and 700 μmol mol−1 The site had been cultivated with annual crops for more than 20 yr. Herbage was harvested three to four times each year. Soil samples from the top 20 cm were collected in February 1995, before plant establishment, and in December 2000 at the end of the project. Overall mean soil organic carbon (SOC) gains across 6 yr were 1.396 and 0.746 g kg−1 in BG and PP, respectively, indicating that BG plots accumulated more SOC than PP. Mean SOC gains in BG plots at 700 and 360 μmol mol−1 CO2 were 1.450 and 1.343 g kg−1, respectively (not statistically different). Mean SOC gains in PP plots at 700 and 360 μmol mol−1 CO2 were 0.949 and 0.544 g kg−1, respectively, an increase caused by elevated CO2 Relative SON accumulations were similar to SOC increases. Overall mean annual SOC accumulation, pooled for forages and CO2 treatments, was 540 kg ha−1 yr−1 Eliminating elevated CO2 effects, overall mean SOC accumulation was 475 kg ha−1 yr−1 Conversion from cropland to forages was a greater factor in SOC accumulation than the CO2 fertilization effect.
Greenhouse Gas Emissions from Forestry Operations
Authors: Sonne Edie
Published: July 2006

Most forest carbon assessments focus only on biomass carbon and assume that greenhouse gas (GHG) emissions from forestry activities are minimal. This study took an in‐depth look at the direct and indirect emissions from Pacific Northwest (PNW) Douglas‐fir [Pseudotsuga menziesii (Mirbel) Franco] forestry activities to support or deny this claim. Greenhouse gas budgets for 408 “management regimes” were calculated using Life Cycle Assessment (LCA) methodology. These management regimes were comprised of different combinations of three types of seedlings (P + 1, 1 + 1, and large plug), two types of site preparation (pile and burn, and chemical), 17 combinations of management intensity including fertilization, herbicide treatment, pre‐commercial thinning (PCT), commercial thinning (CT), and nothing, and four different rotation ages (30, 40, 50, and 60 yr). Normalized to 50 yr, average direct GHG emissions were 8.6 megagrams (Mg) carbon dioxide equivalents (CO2e) ha−1, which accounted for 84% of total GHG emissions from the average of 408 management regimes. Harvesting (PCT, CT, and clear cutting) contributed the most to total GHG emissions (5.9 Mg CO2e per 700 m3 harvested timber), followed by pile and burn site preparation (4.0 Mg CO2e ha−1 or 32% of total GHG emissions) and then fertilization (1.9 Mg CO2e ha−1 or 15% of total GHG emissions). Seedling production, seedling transportation, chemical site preparation, and herbicide treatment each contributed less than 1% of total GHG emissions when assessed per hectare of planted timberland. Total emissions per 100 m3 averaged 1.6 Mg CO2e ha−1 over all 408 management regimes. An uncertainty analysis using Monte Carlo simulations revealed that there are significant differences between most alternative management regimes.
Free‐Air Carbon Dioxide Enrichment of Soybean
Authors: Prior S. A. , Torbert H. A. , Runion G. B. , Rogers H. H. , Ort D. R. , Nelson R. L.
Published: July 2006

Elevated atmospheric CO2 can result in larger plants returning greater amounts of residue to the soil. However, the effects of elevated CO2 on carbon (C) and nitrogen (N) cycling for different soybean varieties have not been examined. Aboveground residue of eight soybean [Glycine max (L.) Merr.] varieties was collected from a field study where crops had been grown under two different atmospheric CO2 levels [370 μmol mol−1 (ambient) and 550 μmol mol−1 (free‐air carbon dioxide enrichment, FACE)]. Senesced residue material was used in a 60‐d laboratory incubation study to evaluate potential C and N mineralization. In addition to assessing the overall effects of CO2 level and variety, a few specific variety comparisons were also made. Across varieties, overall residue N concentration was increased by FACE, but residue C concentration was only slightly increased. Overall residue C to N ratio was lower under FACE and total mineralized N was increased by FACE, suggesting that increased N2 fixation impacted residue decomposition; total mineralized C was also slightly increased by FACE. Across CO2 levels, varietal differences were also observed with the oldest variety having the lowest residue N concentration and highest residue C to N ratio; mineralized N was lowest in the oldest variety, illustrating the influence of high residue C to N ratio. It appears (based on our few specific varietal comparisons) that the breeding selection process may have resulted in some varietal differences in residue quality which can result in increased N or C mineralization under elevated CO2 conditions. This limited number of varietal comparisons indicated that more work investigating varietal influences on soil C and N cycling under elevated CO2 conditions is required.
Carbon Accounting Rules and Guidelines for the United States Forest Sector
Authors: Birdsey Richard A.
Published: July 2006

The United States Climate Change Initiative includes improvements to the U.S. Department of Energy's Voluntary Greenhouse Gas Reporting Program. The program includes specific accounting rules and guidelines for reporting and registering forestry activities that reduce atmospheric CO2 by increasing carbon sequestration or reducing emissions. In the forestry sector, there is potential for the economic value of emissions credits to provide increased income for landowners, to support rural development, to facilitate the practice of sustainable forest management, and to support restoration of ecosystems. Forestry activities with potential for achieving substantial reductions include, but are not limited to: afforestation, mine land reclamation, forest restoration, agroforestry, forest management, short‐rotation biomass energy plantations, forest protection, wood production, and urban forestry. To be eligible for registration, the reported reductions must use methods and meet standards contained in the guidelines. Forestry presents some unique challenges and opportunities because of the diversity of activities, the variety of practices that can affect greenhouse gases, year‐to‐year variability in emissions and sequestration, the effects of activities on different forest carbon pools, and accounting for the effects of natural disturbance.
Assessing Alternatives for Mitigating Net Greenhouse Gas Emissions and Increasing Yields from Rice Production in China Over the Next Twenty Years
Authors: Li Changsheng , Salas William , DeAngelo Benjamin , Rose Steven
Published: July 2006

Assessments of the efficacy of mitigation of greenhouse gas (GHG) emissions from paddy rice systems have typically been analyzed based on field studies. Extrapolation of the mitigation potential of alternative management practices from field studies to a national scale may be enhanced by spatially explicit process models, like the DeNitrification and DeComposition (DNDC) model. Our objective was to analyze the impacts of mitigation alternatives, management of water, fertilizer, and rice straw, on net GHG emissions (carbon dioxide, methane, and nitrous oxide fluxes), yields, and water use. After constructing a GIS database of soil, climate, rice cropping area and systems, and management practices, we ran DNDC with 21‐yr alternative management schemes for each of the approximately 2500 counties in China. Results indicate that, despite large‐scale adoption of midseason drainage, there is still large potential for additional methane reductions from Chinese rice paddies of 20 to 60% over 2000–2020. However, changes in management for reducing CH4 emissions simultaneously affect soil carbon dynamics as well as N2O emissions and can thereby reorder the ranking of technical mitigation effectiveness. The order of net GHG emissions reduction effectiveness found here is upland rice > shallow flooding > ammonium sulfate > midseason drainage > off‐season straw > slow‐release fertilizer > continuous flooding. Most of the management alternatives produced yields comparable to the baseline; however, continuous flooding and upland rice significantly reduced yields. Water management strategies appear to be the most technically promising GHG mitigation alternatives, with shallow flooding providing additional benefits of both water conservation and increased yields.
Root Penetration of Sealing Layers Made of Fly Ash and Sewage Sludge
Authors: Neuschütz Clara , Stoltz Eva , Greger Maria
Published: July 2006

Fly ash and sewage sludge are suggested materials for constructing sealing layers covering mine tailings impoundments. Little is known, however, of their effect on vegetation or resistance to root penetration. We investigate: (i) the ability of different plant species to grow in sealing layers comprising fly ash and sewage sludge, (ii) the impact on plant growth of freshly hardened fly ash compared to aged and leached ash, and (iii) the plant stress response to fly ashes of different properties. A 6‐mo greenhouse study using birch (Betula pendula Roth.), Scots pine (Pinus sylvestris L.), Kentucky bluegrass (Poa pratensis L.), and willow (Salix viminalis L.) demonstrated that no roots could grow into a compacted layer consisting only of ash, while a 6:4, ash–sludge mixture admitted roots into the upper part and a 1:9, ash–sludge mixture was totally penetrated (to 15 cm in depth) by roots of willow and Scots pine. Freshly hardened ash prevented root growth more effectively than aged ash did, as was observed in tests using reed canarygrass (Phalaris arundinacea L.) and pea (Pisum sativum L.). Furthermore, extracts of highly alkaline ash were more toxic to pea in a 48‐h toxicity test than less alkaline ash was. However, stress responses to diluted ash extracts of lower pH, measured as enzyme capacities in dwarf bean (Phaseolus vulgaris L.), were more related to the metal and ion contents. Root penetration of sealing layers is most effectively prevented if little sewage sludge is added, and if ash of high alkalinity is chosen.
Distance and Flow Effects on Microsphere Transport in a Large Gravel Column
Authors: Close Murray E. , Pang Liping , Flintoft Mark J. , Sinton Lester W.
Published: July 2006

Consumption of microbially contaminated ground water can cause adverse health effects and the processes involved in pathogen transport in aquifers need to be understood. The influences of distance, flow velocity, and colloid size on colloid transport were examined in homogenous pea‐gravel media using an 8‐m column and three sizes (1, 5, and 10 μm) of microspheres. Experiments were conducted at three flow rates by simultaneously injecting microspheres with a conservative tracer, bromide. Observed concentrations were simulated with CXTFIT and analyzed with filtration theory. The results demonstrate that colloid concentration is strongly log‐linearly related to transport distance (as suggested by filtration theory) in coarse gravels, similar to our previous field studies. In contrast, the log‐linear relationship is often reported to be invalid in fine porous media. The observed log‐linear relationship is possibly because straining is negligible in the coarse gravels investigated. This has implications in predicting setback distances for land disposal of effluent, and suggests that setback distances in gravel aquifers can be estimated using constant spatial removal rates (f). There was an inverse relationship between transport distance and colloidal concentration, but not with temporal attachment rate (katt) and collision coefficient (α). Increases in flow velocity result in increasing colloidal recovery, katt and α but decreasing f Increases in sphere size result in decreasing colloidal recovery with increasing katt, f, α, and velocity enhancement. Diffusion is the dominant collision mechanism for 1‐μm spheres (81–88%), while settling dominates for 5‐ and 10‐μm spheres (>87%), and interception is very small for all spheres investigated.
Microbial Populations Identified by Fluorescence In Situ Hybridization in a Constructed Wetland Treating Acid Coal Mine Drainage
Authors: Nicomrat Duongruitai , Dick Warren A. , Tuovinen Olli H.
Published: July 2006

Microorganisms are an integral part of the biogeochemical processes in wetlands, yet microbial communities in sediments within constructed wetlands receiving acid mine drainage (AMD) are only poorly understood. The purpose of this study was to characterize the microbial diversity and abundance in a wetland receiving AMD using fluorescence in situ hybridization (FISH) analysis. Seasonal samples of oxic surface sediments, comprised of Fe(III) precipitates, were collected from two treatment cells of the constructed wetland system. The pH of the bulk samples ranged between pH 2.1 and 3.9. Viable counts of acidophilic Fe and S oxidizers and heterotrophs were determined with a most probable number (MPN) method. The MPN counts were only a fraction of the corresponding FISH counts. The sediment samples contained microorganisms in the Bacteria (including the subgroups of acidophilic Fe‐ and S‐oxidizing bacteria and Acidiphilium spp.) and Eukarya domains. Archaea were present in the sediment surface samples at <0.01% of the total microbial community. The most numerous bacterial species in this wetland system was Acidithiobacillus ferrooxidans, comprising up to 37% of the bacterial population. Acidithiobacillus thiooxidans was also abundant. Heterotrophs in the Acidiphilium genus totaled 20% of the bacterial population. Leptospirillum ferrooxidans was below the level of detection in the bacterial community. The results from the FISH technique from this field study are consistent with results from other experiments involving enumeration by most probable number, dot‐blot hybridization, and denaturing gradient gel electrophoresis analyses and with the geochemistry of the site.
Nitrogen and Phosphorus Attenuation within the Stream Network of a Coastal, Agricultural Watershed
Authors: Ensign Scott H. , McMillan Sara K. , Thompson Suzanne P. , Piehler Michael F.
Published: July 2006

Streams alter the concentration of nutrients they transport and thereby influence nutrient loading to estuaries downstream; however, the relationship between in‐stream uptake, discharge variability, and subsequent nutrient export is poorly understood. In this study, in‐stream N and P uptake were examined in the stream network draining a row‐crop agricultural operation in coastal North Carolina. The effect of in‐stream nutrient uptake on estuarine loading was examined using continuous measurements of watershed nutrient export. From August to December 2003, 52 and 83% of the NH4+ and PO43− loads were exported during storms while concurrent storm flow volume was 34% of the total. Whole‐ecosystem mass transfer velocities (Vf) of NH4+ and PO43−, measured using short‐term additions of inorganic nutrients, ranged from 0.1 to 25 mm min−1 Using a mass balance approach, this in‐stream uptake was found to attenuate 65 to 98% of the NH4+ flux and 78 to 98% of the PO43− flux in small, first‐order drainage ditches. For the larger channel downstream, an empirical model based on Vf and discharge was developed to estimate the percentage of the nutrient load retained in‐stream. The model predicted that all of the upstream NH4+ and PO43− load was retained during base flow, while 65 and 37% of the NH4+ and PO43− load was retained during storms. Remineralization from the streambed (vs. terrestrial sources) was the apparent source of NH4+ and PO43− to the estuary during base flow. In‐stream uptake reduced the dissolved inorganic N to dissolved inorganic P ratio of water exported to the N‐limited estuary, thus limiting the potential for estuarine phytoplankton growth.
Assessing waterborne risks: an introduction
Authors: Craun Gunther F. , Calderon Rebecca L. , Wade Timothy J.
Published: July 2006

Information in this paper can help readers evaluate the results of epidemiologic studies of waterborne disease risks. It is important that readers understand the various epidemiologic study designs, their strengths and limitations, and potential biases. Terminology used by epidemiologists to describe disease risks can be confusing. Thus, readers should not only evaluate the adequacy of the information to estimate waterborne risks but should also understand how the risk was estimated. For example, one author's definition of attributable risk may be quite different from another author's in terms of the population to which the risk may apply and how it should be interpreted.
A review of household drinking water intervention trials and an approach to the estimation of endemic waterborne gastroenteritis in the United States
Authors: Colford John M. , Roy Sharon , Beach Michael J. , Hightower Allen , Shaw Susan E. , Wade Timothy J.
Published: July 2006

The incidence of acute gastrointestinal illness (AGI) attributable to public drinking water systems in the United States cannot be directly measured but must be estimated based on epidemiologic studies and other information. The randomized trial is one study design used to evaluate risks attributable to drinking water. In this paper, we review all published randomized trials of drinking water interventions in industrialized countries conducted among general immunocompetent populations. We then present an approach to estimating the incidence (number of cases) of AGI attributable annually to drinking water. To develop a national estimate, we integrate trial results with the estimated incidence of AGI using necessary assumptions about the estimated number of residents consuming different sources of drinking water and the relative quality of the water sources under different scenarios. Using this approach we estimate there to be 4.26–11.69 million cases of AGI annually attributable to public drinking water systems in the United States. We believe this preliminary estimate should be updated as new data become available.
Observational epidemiologic studies of endemic waterborne risks: cohort, case-control, time-series, and ecologic studies
Authors: Craun Gunther F. , Calderon Rebecca L.
Published: July 2006

Observational studies have assessed endemic waterborne risks in a number of countries. Time-series analyses associated increased water turbidity with increased gastroenteritis risks in several public water systems. Several cohort studies reported an increased risk of gastroenteritis in populations using certain public or individual water systems. Although several case-control studies found increased waterborne risks, they also found increased risks associated with other exposures. An increased risk of campylobacteriosis was associated with drinking untreated water from non-urban areas and some tap waters; other significant risks included contaminated poultry and foreign travel. Increased risks of cryptosporidiosis and giardiasis were associated with drinking water in some populations; other risk factors included foreign travel, day care exposures, and swimming. These observational studies provide evidence that some populations may be at an increased risk of endemic or sporadic illness from waterborne exposures, but not all studies found an increased risk. Differences in waterborne risks may be due to differences in water quality. System vulnerabilities and contamination likely differed in the areas that were studied. The information from these studies may help inform estimates of waterborne illness for the US population but is inadequate to estimate a population attributable risk.
The role of disease burden measures in future estimates of endemic waterborne disease
Authors: Rice Glenn , Heberling Matthew T. , Rothermich Mary , Wright J. Michael , Murphy Patricia A. , Craun Michael F. , Craun Gunther F.
Published: July 2006

The 1996 Safe Drinking Water Act amendments require the US Environmental Protection Agency and the Centers for Disease Control and Prevention to develop a national estimate of the occurrence of waterborne infectious disease that is attributable to public drinking water systems in the United States. Much of the information for developing the national estimate will be derived from epidemiologic data, and the primary outcome of this effort will be an estimate of the number of cases of gastrointestinal illness. While quantifying the number of these cases provides some measure of waterborne disease impact, the usefulness of this measure may be limited because the full spectrum of societal impact also involves consideration of the additional effects of these diseases such as hospitalization costs and lost productivity. If decision-makers wish to compare the impact of waterborne infectious diseases to the impact of some other public health concern (e.g. to aid in resource allocation decisions), then a comparison of case numbers may prove inadequate. Case numbers alone do not provide sufficient information about the severity of different illnesses. Society may value the avoidance of a few cases of severely debilitating illness more than it values the avoidance of many cases of mild illness. In order to compare disparate public health concerns, “burden of disease” measures that incorporate indicators of disease severity, costs, or societal values may prove essential for some types of decisions. We describe epidemiologic measures of severity, quality adjusted life years (QALYs), disability adjusted life years (DALYs), willingness-to-pay, and cost-of-illness methods commonly used for burden of disease estimates, and discuss how some of these summary measures of burden might be used for waterborne disease estimates.
Reinforcing water and sanitation sector reform in South Africa
Authors: Busari Ola , Jackson Barry
Published: July 2006

Some ten years ago, South Africa's newly elected government inherited huge services backlogs with respect to access to water supply and sanitation. About 15 million people were without safe water supply and over 20 million without adequate sanitation services. Since then, the country has made remarkable progress with regard to accelerating the pace of services provision and restructuring and refocusing the entire water sector. Having ensured access to an additional population of over 10 million people, South Africa is well on track to wipe out the infrastructure backlog for basic water supply by 2008, exceeding the Millennium Development Goals (MDG) target. But first, with respect to sanitation for which the national target is universal access to a functioning facility by 2010, the picture is somewhat different. Second, substantial challenges remain in addressing historical inequalities in access to both water supply and sanitation, and in sustaining service provision over the long term.
Catchment water deficits: an application to Zambia's Kafue river basin
Authors: Merrett Stephen
Published: July 2006

In an article in Water Policy (Merrett, Water Policy 7(2), 2005), the author presented a general theory on the likelihood of catchments moving from surplus to deficit in terms of their precipitation's adequacy to meet social, economic and environmental flows. The paper called for networked, international research to test the general theory and its causal hypotheses. The paper presented below applies the theory to the Kafue Basin in Zambia and suggests that understanding river basin surpluses and deficits requires the analysis of various measures of catchment density.
Economic valuation of resuscitating the Dead Sea
Authors: Becker Nir , Katz David
Published: July 2006

As a result of diversion of upstream waters and intensive mineral extraction along its shores, the level of the Dead Sea is dropping at a rate of almost one meter per year, causing the sea continuously to break its own record as the lowest place on earth. The loss of the sea and the accompanying ecological and cultural damage in the basin has traditionally been regarded as an unavoidable consequence of rational economic policy. This study investigates for the first time the non-market economic value of conservation of the Dead Sea basin using both contingent valuation (stated preference) and travel cost (revealed preference) studies. Study results indicate that all three local populations, Israeli, Jordanian and Palestinian, demonstrate a substantial willingness to pay to preserve the cultural and environmental heritage of the region. Such results strengthen the case for conservation of the region, which, heretofore, has relied strictly on ethical and ecological rationales.
Removal of boron (B) from waste liquors
Authors: Jiang J.-Q. , Xu Y. , Simon J. , Quill K. , Shettle K.
Published: July 2006

This paper explores the use of electrocoagulation to remove boron from waste effluent in comparison with alum coagulation. In treating model test wastes, greater boron removals were achieved with electrocoagulation at low doses than conventional alum coagulation when reaction was undertaken for the same conditions (pH 8.5, and initial boron concentration was 500 mg/L). Al electrocoagulation can achieve good boron removal performance (68.3%) at a dose of 2.1 (as molar ratio of Al:B, and for current density of 62.1 A/m2), while alum coagulation can only achieve the maximum boron removal of 56% at a dose of 2.4. Also, Al electrocoagulation can remove 15–20% more boron than alum coagulation for the same dose compared in the treatment of both model test wastes and industry effluent. The estimation of running costs shows that to achieve 75% boron removal from industry waste effluent, i.e. removing 150 g of boron from 1 m3 of effluent, electrocoagulation was 6.2 times cheaper than alum coagulation. The economic advantage of electrocoagulation in the treatment of boron-containing waste effluent is thus significant.
Biological treatment of industrial wastes in a photobioreactor
Authors: Tamer E. , Amin M.A. , Ossama E.T. , Bo M. , Benoit G.
Published: July 2006

An algal-bacterial consortium was tested for the treatment from a coke factory. A Chlorella vulgaris strain and a phenol-degrading Alcaligenes sp. were first isolated from the wastewater treatment plant to serve as inocula in the subsequent biodegradation tests. Batch tests were then conducted with samples from the real wastewater or using a synthetic wastewater containing 325 mg phenol/l and 500 mg NH4+/l as target pollutants. Direct biological treatment of the real wastewater was not possible due to the toxicity of organic compounds. Activated carbon adsorption and UV(A-B)-irradiation were efficient in detoxifying the effluent for subsequent biological treatment as inoculation of pretreated samples with the algal-bacterial consortium was followed by complete phenol removal and NH4+ removal of 45%. Complete phenol removal and 33% NH4+ removal were achieved during the fed-batch treatment of artificial wastewater at 6 d hydraulic retention time (HRT). Under continuous feeding at 3.6 d HRT, phenol and NH4+ removal dropped to 58 and 18%, respectively. However, complete phenol removal and 29% NH4+ removal were achieved when 8 g NaHCO3/l was added to the artificial wastewater to enhance algal growth. This study confirms the potential of solar-based industrial wastewater treatment based on solar-based UV pretreatment followed by algal-bacterial biodegradation.
Dynamical modelling of an activated sludge system of a petrochemical plant operating at high temperatures
Authors: Maqueda M.A.M. , Martinez D. Sergio A. , Narváez D. , Rodriguez R. Miriam G. , Aguilar L. Ricardo , Herrero V. Victor M.
Published: July 2006

The Mexican petrochemical industry, Morelos S.A. de C.V., is one of the biggest and more important petroleum industries in Mexico and Latin America. It has an activated sludge system to treat its wastewater flow, which is approximately 7,000 m3/d. The wastewater contains volatile organic carbon substances classified as toxics. The old surface aeration system was changed for fine bubble diffusers; however, one major drawback of the new aeration system is that the temperature in the bioreactor has increased due to the compression of the air, which at the compressor exit reaches 85 °C. This effect results in the temperature in the bioreactor attaining 32 °C during the fall, whereas in the spring and summer, the bioreactor temperature reaches higher values than 40 °C. The high temperatures reduce the microorganism activity and cause a higher volatilisation rate of volatile compounds, among other effects, which affect the performance of the biological treatment. This work was performed to obtain a better modelling of the wastewater treatment from the petrochemical industry. The model describes the effect of the temperature on the performance of the biological treatment. The model was obtained from tests that were carried out in laboratory reactors with 14 L capacity, which were operated at different temperatures (from 30 to 45 °C), with the same wastewater and conditions as the actual system.
Treatment of dye works wastewater using anaerobic–oxic biological filter reactor packed with carbon fibre and aerated with micro-bubbles
Authors: Yamashita T. , Yamamoto-Ikemoto R. , Sakurai E.
Published: July 2006

A new anaerobic–oxic biological filter reactor, which was packed with carbon fibre and aerated with micro-bubbles, was proposed. The reactor performance was examined using dye works wastewater compared with the activated sludge reactor. Effluent SS from the experimental reactor was significantly lower than that from the activated sludge reactor, and transparency was higher. Temperatures of the activated sludge reactor were over 35 °C and DOC removal ratios were 40–80% depending on the influent wastewater. On the other hand, the DOC removal efficiency of the experimental reactor was over 70%, when the reactor temperature was over 22 °C. In the anaerobic zone, sulphate reduction occurred predominantly and acetate was produced. In the oxic reactor, sulphur oxidation and organic removal occurred. When the amount of sulphate reduction in the anaerobic zone increased, DOC and colour in effluent decreased. The sulphate reducing activity of biofilm at 30 °C was three times higher than those at 20 °C. The sulphate reducing activity of biofilm in the oxic zone was higher than those in the anaerobic zone, meaning that the sulphate reduction-oxidation cycles were established in the biofilm of the oxic zone. Microbial community of sulphate reducing bacteria was examined by in situ hybridisation with 16S rRNA targeted oligonucleotide probes. Desulfobulbus spp. was most common sulphate reducing bacteria in the anaerobic zone. In the oxic zone, Desulfobulbus spp. and Desulfococcus spp. were observed.
Operation and management of the Fukashiba treatment plant
Authors: Ochiai E. , Igarashi T. , Itou S. , Seya H. , Matsui S.
Published: July 2006

Since the opening of the Fukashiba Treatment Plant in 1970, the number of industries and the amount of wastewater requiring treatment in the service area have been steadily increasing. In response to the recent economic downturn in Japan, these rates of increase have slowed, but are not decreasing. The pollution load in the wastewater from these industries has decreased and is now stable. Unlike the case of ordinary domestic sewage, the effects of the various types of substances contained in wastewaters delivered from the petrochemical complex to the treatment plant, for example, corrosion, are quite large. Measures to deal with corrosion problems, such as replacement or modification of the facilities, improvement of the efficiencies of facility operation and wastewater treatment, and improvement of measures against odours, are being implemented.
Study on risk management of heavy metals for reuse of biosolids
Authors: Ozaki M. , Suwa M. , Suzuki Y.
Published: July 2006

The behaviour of heavy metals was investigated at 22 wastewater treatment plants (WWTPs). In addition, the survey of heavy metal balance was conducted in detail at one WWTP. For the measurement, 22 types of heavy metals were selected from the chemical materials of pollutant release and transfer register (PRTR). There were some heavy metals, which were detected not in wastewater but in dewatered sludge. By means of the detailed survey at one WWTP, 60 to 80% of some heavy metals, such as B, Mn, Co, Ni and Mo, were discharged with treated water. According to the results of PRTR, Zn, B and Mn accounted for a large part of the discharge into the water course. To estimate the behaviour of heavy metals in the environment, leaching tests were applied to the products made of biosolids. During a series of leaching tests for building materials, it was observed that the concentration of heavy metals was very small, but the ratio of increase keeps a constant value. Therefore, it was considered that the acid extractable contents of heavy metal would be important.
Application of biological activated carbon anaerobic reactor for treatment of hazardous chemicals
Authors: Tsuno H. , Kawamura M. , Oya T.
Published: July 2006

An expanded-bed anaerobic reactor with granular activated carbon (GAC) medium has been developed to treat wastewaters that contain a high concentration of inhibitory and/or refractory organic compounds as well as readily degradable organic compounds. The process is characterised by a combination of two removal mechanisms; adsorption on GAC and biological degradation by microorganisms grown on GAC. Applicability of the reactor to treatment of phenol, chloroacetaldehyde (CAA), pentachlorophenol (PCP) and tetrachloroethylene (PCE) was discussed based on experimental data. All chemicals focused on here were removed well and stably at a removal efficiency of more than 98% even during starting operation and shock load operation. Chemicals in influent that exceeded biological degradation capacity was initially adsorbed on GAC and then gradually degraded, and hence the adsorptive capacity of GAC was regenerated biologically. These results proved that a biological activated carbon anaerobic reactor was effective for treatment of wastewater containing hazardous chemicals, especially for strongly absorbable chemicals, as well as readily degradable organic compounds at high concentration.
Biodegradation of high 4-chlorophenol concentrations in a discontinuous reactor fed with an optimally controlled influent flow rate
Authors: Moreno-Andrade I. , Buitrón G. , Pérez J. , Betancur M.J. , Moreno J.A.
Published: July 2006

This work presents the results of the application of an optimally controlled influent flow rate strategy to biodegrade, in a discontinuous reactor, high concentrations of 4-chlorophenol used as toxic compound model. The influent is fed into the reactor in such a way as to obtain the maximal degradation rate, thus avoiding the inhibition of the microorganisms. The optimal strategy was able to manage increments of toxic concentrations in the influent up to 7,000 mg 4CP/L without any problem. It was shown not only that higher concentrations of toxic could be treated, but also that a reduction in degradation time (around 52%) and in the supplied air volume was obtained.