bluuebunny/crossref_metadata_2025 huggingface dataset:
Survey of the Ecological State of Eight Man-Made Lakes Within the City Limits of Freiburg, Germany
Authors: Pulvermüller Agnes G. , Müller Heidulf E.
Published: March 2019

The survey of the ecological condition of eight lakes within the city limits of Freiburg included hydrochemical measurements and analyses (oxygen profiles, Secchi depth, pH, biochemical oxygen demand) together with biological parameters (chlorophyll a, phytoplanktonbiomass, Escherichia coli counts), as well as parasitic examinations. Only some of the investigated parameters are presented here. Seven of the eight lakes were found to be eutrophic. The process of eutrophication appears to be still in progress. One lake can be considered to be hypertrophic. Schistosome dermatitis was observed. The water quality in general was considered to be acceptable; suggestions to maintain or improve the water quality are made.
Retrofitting Stormwater Ponds for Water Quality Control
Authors: Marsalek J. , Watt W. E. , Henry D.
Published: March 2019

During the last 15 years, many stormwater ponds were built in Canada. These ponds were designed to control runoff flows by peak shaving and thereby prevent flooding resulting from urbanization, but they are ineffective in protection of water quality in the receiving waters. Thus, one of the emerging challenges in urban water management is the retrofitting of existing stormwater ponds to meet the current environmental concerns. The retrofitting measures proposed include changes in flow regimes, storage pool volumes and flow velocities, achievable by structural changes in inlet, storage and outlet structures; treatment of runoff by sedimentation or filtration; enhancement of biological processes contributing to pollutant removal through longer detentions and introduction of aquatic plants; and, improvement of aquatic life habitat. A case is made for an ecosystem approach where the pond is one element in the urban stormwater treatment train which controls catchment, pond and receiving waters.
Impact of a Modernized Bleached Kraft Mill on White Sucker Populations in the Spanish River, Ontario
Authors: Servos M. R. , Carey J. H. , Ferguson M. L. , Van Der Kraak G. , Ferguson H. , Parrott J. , Gorman K. , Cowling R.
Published: March 2019

The impact of effluent from a modern bleached kraft pulp mill was examined on the Spanish River, Ontario. The mill utilizes oxygen deligniflcation, chlorine dioxide substitution, and secondary treatment (aerated lagoon) resulting in the production of < 1.5 kg AOX/air dried metric tonne (ADMT) of pulp. However, the relatively low river flow results in an AOX concentration in the receiving waters of approximately 0.15 mg/L, similar to the level reported for other sites receiving both treated and untreated bleached kraft mill effluents. There was only a minimal reduction in the concentration of AOX and chlorophenolics in river water sampled over 51 km downstream of the outfall. In early August 1990, 14 to 30 live white sucker (Catostomus commersoni) were collected at each of two sites upstream and three sites downstream of the outfall (2, 28, 51 km). Each fish was examined for gross pathological changes, several condition indices, hematocrit, plasma electrolytes, plasma testosterone, and hepatic mixed function oxygenase enzyme activity (ethoxyresorufin-o-deethylase). Selected fish were also examined histologically for liver, gill, kidney, spleen, heart, muscle and gonad abnormalities. Liver somatic index was elevated in fish immediately below the outfall while elevation of EROD activity persisted 51 km downstream. There were no significant histopathological lesions observed observed and there were no consistent patterns observed in condition indices or plasma parameters.
Comprehensive Study of a Bleached Kraft Mill Aerobic Secondary Treatment System
Authors: Fein J. , Beavan M. , Effio A. , Gray N. , Moubayed N. , Cline P.
Published: March 2019

A comprehensive study (physical, chemical and biological parameters) was made of a conventional secondary treatment system (aeration stabilization basin) linked to a state-of-the-art bleached kraft mill. Overall the system removed 88% of the BOD, 62% of the COD, 47% of the TOC, 56% of the AOX and 69% of the suspended solids present in the influent stream. Of the total removed, the first aeration cell was the most active area of the system, responsible for the removal of 70% of the BOD5, 57% of the COD, 43% of the TOC, 75% of the AOX, and all of the acute toxicity entering the system. Cell 2 was found to be carbon limited. Unlike Cell 1, Cell 2 played a significant role in suspended solids removal.
RBC Kinetics in Treating Domestic and Industrial Dairy Wastewater Under Low and High Organic Loading Conditions
Authors: Surampalli Rao Y. , Baumann E. Robert
Published: March 2019

A full-scale, four-stage RBC (rotating biological contactors) plant, having parallel trains used to treat domestic and industrial dairy wastewater, failed to meet standard secondary effluent limits due to overloading in the two initial stages. The plant was first operated under normal loading; subsequently the load to the plant was increased in an incremental fashion by increasing the load from the dairy. This was done to evaluate the effectiveness of the use of supplemental aeration to eliminate oxygen-limiting conditions in the overloaded stages. An enlarged first stage was later created to lower the organic load to the initial stages by removing the wooden baffles between the first and second stages. The experimental work at the plant was conducted for approximately six months, during which daily 24-hour composite samples were collected at the end of each stage and analyzed for various parameters.

The experimental results indicated that substrate removal with supplemental air and an enlarged first stage followed first-order kinetics at both lower and higher organic loadings. Without supplemental air, substrate removal followed second-order kinetics at lower loadings and zero-order kinetics at higher organic loadings. With an enlarged first stage only, substrate removal followed first-order kinetics at lower loading and zero-order kinetics at higher loadings. Overall, RBC performance improved significantly with supplemental air and an enlarged first stage. The results also suggest that higher organic loadings and removals can be achieved in the presence of supplemental air due to the maintenance of higher dissolved oxygen levels in the mixed liquor.
Utilization of Calcium-Loaded Low-Rank Brown Coals for Removing Heavy Metals from Waste Solutions
Authors: Horáćek J. , Punćochář M. , Drahoš J.
Published: March 2019

Calcium-loaded low-rank brown coal was used to extract various heavy metals (Cu, Hg, Pb, Zn) from aqueous solutions. The results showed a high efficiency of extraction — almost 99.9% of metals in the concentration range of 3,000–10,000 mg/1 were removed from the solutions. Both the batch and continuous modes of contacting were tested and for the latter, the process of penetration was also studied.
Distribution of Chlorobenzenes, Pesticides and PCB Congeners in Lake Ontario Near the Toronto Waterfront
Authors: Halfon Efraim , Poulton Don
Published: March 2019

Concentrations of 89 toxic organic pollutants (25 contaminants, including chlorobenzenes and pesticides, and 64 PCB isomers) were measured in Lake Ontario along the Toronto Waterfront area during the spring, summer and fall of 1987. Data indicate that Humber Bay, the inner harbour, and the areas near the Toronto Main Sewage Treatment Plant (STP) are the most polluted. While contaminant levels in some offshore areas are high, average levels for most contaminants are similar to whole-lake levels. Lake Ontario receives large amounts of pollutants from atmospheric sources and the Niagara River. Consequently, the impact of both local and whole-lake sources is felt in the Toronto Waterfront Area. Thus, even if all local sources of pollution were removed, the Toronto Waterfront Area would probably remain affected by other sources, primarily the Niagara River. Concentrations of toxic pollutants would remain approximately the same as far as two kilometers from shore.
Comparaison entre la capacité de bioaccumulation du mercure chez le gastéropode de faible longévité Vivipanis georgianus (Lea) et le pélécypode Elliptio complanata (Lightfoot) dans l’estuaire d’eau douce du fleuve Saint-Laurent
Authors: Tessier Louis , Vaillancourt Guy , Pazdernik LeRoy
Published: March 2019

Nous avons comparé la capacité de bioaccumulation du mercure chez le gastéropode de faible longévité Viviparus georgianus (Lea) ainsi que chez le pélécypode Elliptio complanata (Lightfoot) échantillonnés dans le haut estuaire supérieur et inférieur du fleuve Saint-Laurent. La concentration en mercure a été mesurée dans la chair et la coquille des mollusques. Des comparaisons ont été faites entre les espèces et entre les deux milieux échantillonnés. Les résultats indiquent que la teneur en mercure du secteur étudié est relativement faible. Le prosobranche V. georgianus concentre le mercure biodisponible du sédiment et le pélécypode E. complanata celui de l’eau, résultant de modes alimentaires différents. Le taux de déposition du mercure dans la coquille dépend de la concentration biodisponible dans l’eau lors de la formation de celle-ci.
Relationships Between Concentrations of Metals in Sediment and Two Species of Freshwater Mussels in the Ottawa River
Authors: Metcalfe-Smith J.L. , Merriman J.C. , Batchelor S.P.
Published: March 2019

This study examined the relationships between concentrations of metals in sediment and freshwater mussels from the Ottawa River to determine whether mussels could provide useful Information on the bioavailability of sediment-associated metals. Sediment and two species of mussels, Elliptio complanata and Lampsilis radiata (F. Unionidae), were collected from several sites on the river and analyzed for residues of nine metals. Significant positive correlations between concentrations in mussels and sediment were observed for only four metals (Cd, Cr, As, Se), even though the readily extractable or “bioavailable” fraction of the total load in sediment was compared for all metals except As, Se and Hg. Lack of correlation for other metals may have been due to a narrow range of exposure concentrations tested or to the regulatory capabilities of the mussels themselves. Interspecific differences in bioaccumulation were observed for As, Cr, Cu, Ni and Zn. Interpretation of data from mussel monitoring programs requires knowledge of the complex processes influencing bioaccumulation.
An Overview of Dynamics and Biotoxicity of Metals in the Freshwater Environment
Authors: Huang P.M.
Published: March 2019

The toxic metals, including metalloids, in the freshwater ecosystem are largely associated with surficial sediments and suspended particulate materials. These metals are in dynamic equilibrium with interstitial water and the overlying water column. The bioavailability and toxicity of metals in the freshwater environment are influenced by their speciation and dynamics. Our current understanding of the nature of metal partitioning in particulate materials, interstitial water and the overlying water column is quite limited because of the limitations of the metal fractionation methods and difficulties in obtaining thermodynamic information which approaches the realities in streams, rivers and lakes. Little is known about the in situ metal dynamics. Kinetic studies of metal reactions, thus, warrant in-depth research for years to come. Besides inorganic and organic colloids, microbes contribute to metal transformations. The impact of the interactions of microbes with minerals and organic components on the dynamics and biotoxicity of metals merits attention. Over the last decade, there has been much research on the development of hydrochemical models for better understanding and predicting metal transport in the freshwater system, yet little research has been focused on how well they describe field data. The supply of biologically available metals in the freshwater environment is governed by a series of physical, physicochemical, biochemical and biological processes. To date, there are very few studies on the subject in which an integrated approach has been taken. The roles of these interacting processes in affecting metal dynamics and their impacts on freshwater toxicology deserve increasing attention.
Effects of Speciation of Toxic Metals on their Biological Activity
Authors: Kushner Donn J.
Published: March 2019

Some properties of different toxic metals and metal ions are considered, especially the ability of the latter to form complexes with inorganic and organic ligands of low and high molecular weight. The effect of such complexation, of pH changes, and of changes of valence on toxic action towards microorganisms (including bacteria, algae, yeast and fungi) and higher animals are reviewed. Mechanisms of microbial tolerance towards toxic metals, especially those that involve changes in metal speciation, are also considered. Intracellular binding compounds, including metallothioneins and phytochelatins, which control metal movement and toxicity are briefly described. Neurological, immunological and carcinogenic effects of different metallic species on humans and other animals are also described.
Algal Bioassays for Metal Toxicity Identification
Authors: Peterson Hans G. , Nyholm Niels
Published: March 2019

There is a need for algal bioassays that reflect the toxicity and bioavailability of metals in aquatic ecosystems. Reliable results can be achieved only when physical, chemical and biological factors are carefully controlled throughout the test period, and when they reflect the environmental conditions to be simulated. These can be either some consensus universal standard conditions or they can be specific environmental scenarios. Tests carried out under different controlled physical-chemical experimental conditions will give us an understanding of metal toxicity as a function of the environmental conditions. Here we address some factors that ought to be considered in the development of sensitive, cost-effective and ecologically realistic algal bioassays. The goal of bioassay protocol development is to produce algal toxicity data that are reproducible and can be used in risk assessments for aquatic ecosystems, and to detect the effects of metal contaminants in these systems.
Effects of Environmental Factors and Primary Production on the Distribution and Methylation of Mercury in a Chain of Highly Eutrophic Riverine Lakes
Authors: Jackson Togwell A.
Published: March 2019

A chain of six highly eutrophic lakes linked by the Qu’Appelle River of southern Saskatchewan is polluted with mercury (Hg) introduced by the river from sources upstream from the lakes. Microbial production of methyl Hg (CH3Hg+) from inorganic Hg in the river and lakes is independent of the total abundance of inorganic Hg but is strongly dependent on environmental conditions that control microbial activity, including the factors which determine the abundance of phytoplankton, the primary source of the organic nutrient substrates utilized by Hg methylating and demethylating microbes. Most of the inorganic Hg transported into the lakes by the river is evidently adsorbed to FeOOH coatings on detrital clay and is deposited with the clay on a delta near its point of entry into the first lake of the series, although afterwards some of the Hg may be remobilized and transferred to organic matter and sulfides on reduction and dissolution of FeOOH in anaerobic bottom environments. Thus, inorganic Hg concentrations in lake water and sediments are highest in deltaic environments near the inflow; but Hg methylating activity is most intense in lake basins further downstream, where conditions are more favourable for the growth of methylating microbes, owing to a greater abundance of organic nutrient substrates derived from phytoplankton blooms and a higher proportion of organic matter to mineral detritus (and possibly a lower concentration of toxic pollutants). Therefore, the concentrations of CH3Hg+ and inorganic Hg in the first lake of the series are inversely related even though a supply of bioavailable inorganic Hg is essential to CH3Hg+ production. The most favourable conditions for CH3Hg+ production occur in lake basins characterized by low concentrations of fluvial clay and silt, deep water of high transparency, high primary productivity, intense heterotrophic microbial activity, and low sediment Eh. Despite the occurrence of relatively high concentrations of sulfide in these extremely eutrophic environments, the net effect of the prevailing conditions is stimulation of Hg methylating activity. The CH3Hg+ generated in the lake is supplemented by fluvial CH3Hg+ formed when plankton blooms develop in the river under conditions of slack flow.
Application of Molecular Biology Techniques for Isolating and Monitoring Pollutant-Degrading Bacteria
Authors: Greer Charles , Masson Luke , Comeau Yves , Brousseau Roland , Samson Rejean
Published: March 2019

The characterization of genes from bacterial organic pollutant degradation pathways has enabled the development and application of molecular techniques to study the microbial ecology of contaminated environments. The techniques include the use of catabolic gene probes, nucleic acid hybridization techniques, and use of the polymerase chain reaction (PCR) to amplify specific target regions of nucleic acid.

Gene probes encoding enzymes involved in the dissimilation of chlorobiphenyls (bphC) and chlorobenzoic acids (clcA) have been used to isolate bacteria from polychlorinated biphenyl (PCB) contaminated soils. The xylE (toluene, xylene degradation), ndoB (naphthalene degradation) and alkB (C6 to C12 n-paraffin degradation) gene probes have been used to isolate indigenous bacteria from petroleum hydrocarbon-contaminated soils and to enrich bacteria expressing these genotypes for subsequent bioaugmentation of the soils.

A reporter gene system has been developed to study the fate of a 2,4-dichlorophenoxyacetate-degrading pseudomonad. The genes for lactose utilization (lacYZ) and for bioluminescence (luxAB) were integrated into the chromosome, providing genetically stable, non-transferable markers. This strain can be unequivocally differentiated from indigenous bacteria and is detectable to 10 viable cells per gram of soil.
Comparison of Captor System with Other Fixed-Film Media Nitrification Systems
Authors: Banerji Shankha K. , Liu Min-Hsin
Published: March 2019

Laboratory experiments were conducted at 20–25°C to compare the performance of three different types of Captor media with a rock-gravel media and a plastic trickling filter-packing media. The open-cell Captor media performed better than the gravel media and plastic trickling filter media at all loading rates up to 0.592 kg NH3-N/m3/d. Even at the highest NH3-N loading rate, the effluent NH3-N concentration was less than 1.0 mg/L in the open-cell Captor media effluent. The closed-cell, carbon-impregnated Captor media did not perform as well as the open-cell media. The reduction of temperature to 10–12°C reduced the performance of the Captor system to some extent, but NH3-N levels of less than 1.0 mg/L were obtained at loading rates up to 0.339 kg NH3-N/m3/d. At the highest NH3-N loading rate tested (0.852 kg NH3-N/m3/d), the nitrification performance of all the systems decreased, probably due to D.O. limitations, increased BOD loading and the consequent displacement of the nitrifiers by the heterotrophic organisms and lower detention time.
Use of Fly Ash in the Removal of Copper, Nickel and Zinc from Wastewater
Authors: Viraraghavan T. , Dronamraju Murali M.
Published: March 2019

The effectiveness of fly ash in adsorbing copper, nickel and zinc was studied by conducting batch kinetic and isotherm studies. The effect of contact time, pH, initial concentration of the adsorbate, and temperature on the adsorption process was studied. Fly ash was found to be an effective adsorbent. The contact time necessary to attain equilibrium was found to be two hours. Maximum adsorption occurred in the pH range of 3.0 to 3.5. The Langmuir and Freundlich models were found to be applicable to the adsorption data of copper, nickel and zinc. Thermodynamic parameters suggested the exothermic nature of the adsorption process.
Sulphur Management Strategies in Anaerobic Treatment of a BCTMP/TMP Effluent
Authors: Stephenson R.J. , Branion R.M.R. , Pinder K.L.
Published: March 2019

Anaerobic treatment of a bleached chemithermomechanlcal/ thermomechanical BCTMP/TMP (2:1 by volume) effluent obtained from Quesnel River Pulp Co. was studied on a laboratory scale at 35°C. The experimental apparatus consisted of upflow anaerobic sludge bed (UASB) acidogenic reactors followed by hybrid upflow anaerobic sludge bed/fixed-film methanogenic reactors.

Under anaerobic conditions, sulphite and sulphate are reduced to sulphide, presenting problems of toxicity, odour, corrosion and reduced methane yields, and treatment efficiencies. The fate of these compounds was examined under various hydraulic retention times and sulphur management strategies, including: (i) pH control; (ii) inhibition of the sulphur reducing bacteria via molybdenum addition; and (iii) stripping hydrogen sulphide dissolved in the reactor liquor by recycling hydrogen sulphide-free off gas.

Controlling the pH of the acidogenic reactor from 5.5 (uncontrolled) to 8.0, in order to shift the formed sulphide species to the less toxic ionic form, appeared to be ineffective in promoting wastewater treatment efficiency. Molybdenum addition to the wastewater, tested at levels from 0.1 to 1.0 mM, was effective at 1.0 mM in retarding sulphide formation. Hydrogen sulphide stripping, using scrubbed and recycled off gas, appeared to be the most effective means of sulphur management for this type of wastewater under these conditions.
Évaluation écotoxicologique de la baie des Anglais à Baie-Comeau (Québec)
Authors: Pellerin-Massicotte Jocelyne , Vincent Bruno , Pelletier Émilien
Published: March 2019

La baie des Anglais à Baie-Comeau (Québec) est un site industriel reconnu comme étant contaminé aux hydrocarbures et aux biphényls polychlorés (BPC). Une expérience de transfert à moyen terme de deux bivalves marins, Mya arenaria et Mytilus edulis L., a été réalisée entre un site de référence en aval de la baie des Anglais (Franquelin) et des sites contaminés près de Baie-Comeau suivant un gradient de contamination déterminé selon des données physico-chimiques antérieures. Les analyses chimiques de contaminants ont montré qu’il n’y a pas eu d’enrichissement en hydrocarbures, au mercure et en BPC pour toute la durée du protocole mais, parmi les sondes bioanalytiques choisies pour évaluer l’état de santé de cet écosystème, celles qui se sont avérées les plus sensibles chez Mya arenaria furent le glycogène et les lipides dans les gonades, et pour les deux bivalves, la fragilité de la membrane lysosomale de la glande digestive qui est un excellent indicateur de stress toxique. Les présents résultats sont compatibles avec un modèle qui consisterait à établir une évaluation ecotoxicologique d’un écosystème que l’on soupçonne perturbé par la pollution par (i) l’analyse de la bioaccumulation des substances toxiques que l’on croit présentes dans l’écosystème (hydrocarbures, BPC et métaux lourds) et (ii) l’évaluation des effets physiologiques et biochimiques des polluants à l’aide de sondes bioanalytiques appropriées.
Potentiel de la spectroscopic par effet mirage au domaine de la pollution de l’eau: effets de polluants sur l’activité photosynthétique
Authors: Charland Marc , Lorrain Lucie , Leblanc Roger M.
Published: March 2019

Suite à l’absorption d’une lumière monochromatique modulée, un échantillon dégage de la chaleur via les processus de désactivation thermique. La spectroscopic photothermique de déflection (par effet mirage) détecte les changements d’indice de réfraction d’un fluide causés par la perte de chaleur de l’échantillon. Cette méthodologie expérimentale permet d’étudier différents niveaux d’organisation de l’appareil photosynthétique. Des spectres d’action ont été obtenus et montrent une bonne résolution. De plus, l’activité de l’échantillon est mesurée via la détermination de l’emmagasinage d’énergie. Il est ainsi possible de suivre l’activité photosynthétique suite à l’addition d’un agent polluant dans le milieu, ce qui confère à la méthode une capacité de déterminer l’effet de cet agent polluant, en plus de son site d’action.
Réponse des cellules du foie de truite arc-en-ciel exposées à des métaux lourds toxiques
Authors: Marion M. , Denizeau F.
Published: March 2019

Plusieurs métaux toxiques tels le cadmium (Cd), le mercure (Hg) et le cuivre (Cu) possèdent de nombreuses applications domestiques et industrielles. Au Canada, les métaux lourds sont reconnus comme polluants aquatiques majeurs. Notre laboratoire a récemment entrepris l’examen des effets des métaux lourds sur les hépatocytes de truite arc-en-ciel. Vu le manque de connaissances sur les interactions toxiques des métaux chez les organismes aquatiques, une attention particulière est portée à l’étude des mélanges. Les objectifs du présent travail sont (!) de déterminer l’accumulation du Cd, Hg et Cu par les hépatocytes de truite lors d’une exposition à ces métaux, seuls ou combinés, et (ii) de déceler les perturbations métaboliques induites telles que reflétées par l’activité de synthèse protéique des cellules. L’incorporation d’arginine tritiée ([3H]Arg) a été mesurée sur des hépatocytes soumis à des concentrations croissantes de Cd, Hg ou Cu. Dans chaque cas, on a noté une diminution de l’incorporation de 3H dans les protéines cellulaires. Cependant, si on en juge par les niveaux minimums nécessaires pour l’observer, le Cu apparaît comme le métal le moins cytotoxique. Un second groupe d’expériences a cherché à détecter si le Hg ou le Cu pouvaient altérer la réponse toxique causée par le Cd. Une incorporation légèrement plus faible a été observée lorsque le Hg est ajouté au Cd, mais sans que celle-ci soit statistiquement significative. De la même façon avec la paire Cd/Cu, il n’y a pas eu de modulation de la réponse au Cd par l’ajout du Cu. La capture de métaux a été évaluée dans les mêmes conditions que précédemment. L’analyse des métaux montre que les hépatocytes de truite sont capables de capter des quantités significatives des métaux non essentiels Cd et Hg. De plus, aucune compétition réciproque n’est observée pour leur entrée dans les hépatocytes. Enfin, en présence de Cd, la teneur cellulaire en Cu est comparable à celle des témoins. Les modèles cellulaires présentent plusieurs avantages dans le domaine de la toxicologie environnementale dont: la détection du potentiel nocif d’échantillons environnementaux complexes ainsi que l’Investigation du mode d’action des polluants toxiques.
Étude de l’activité photosynthétique à l’aide de la spectroscopic photoacoustique: applications potentielles en écotoxicologie
Authors: Charlebois Denis , Veeranjaneyulu Konka , Leblanc Roger M.
Published: March 2019

La spectroscopic photoacoustique permet la détection de la chaleur émise lors de désactivations thermiques suite à l’absorption, par un échantillon, de la lumière monochromatique modulée. En faisant varier la longueur d’onde du faisceau d’analyse, nous obtenons un spectre comparable à celui obtenu par la spectroscopic d’absorption. La spectroscopic photoacoustique possède l’avantage d’être applicable aux échantillons dont les propriétés optiques ne se prêtent pas aux techniques spectroscopiques conventionnelles, par exemple dans le cas des algues unicellulaires. Cette technique permet, en plus de l’analyse spectrale, la mesure de l’activité photosynthétique d’échantillons sains ou soumis à divers agents environnementaux (polluants, chaleur, …). Des résultats obtenus avec Anacystis nidulans, Phaeodactylum tricornutum et Pisum sativum sont présentés dans le présent travail. Nous croyons que les possibilités de la spectroscopic photoacoustique sont suffisantes pour susciter l’intérêt des chercheurs dans le domaine de la toxicologie et en particulier dans l’évaluation des dangers environnementaux reliés à l’utilisation des substances toxiques.
Endocrine Responses as Indicators of Sublethal Toxic Stress in Fish from Polluted Environments
Authors: Hontela Alice , Rasmussen Joseph B. , Chevalier Gaston
Published: March 2019

Development of new methods for detection of sublethal toxic effects of pollutants in aquatic organisms has become a focus of interest in ecotoxicology. The endocrine response to pollutants is an integral part of the homeostatic physiological processes activated in response to environmental stressors including pollutants. Changes in concentrations of hormones, particularly those regulating vital functions such as osmoregulation, energy metabolism, reproduction, or growth, may have potential as early warning indicators of toxic stress in fish. We review the recent literature in fish endocrine toxicology and illustrate the use of hormonal indicators in detection of acid stress in the brook trout. Salvelinus fontinalis, from lakes in the Canadian Shield, and of general toxic stress in the pike, Esox lucius, and the perch, Perca flavescens, from the St. Lawrence River system polluted by a mixture of chemicals.
Phosphorus Removal from Aerated Lagoons Using Alum, Ferric Chloride and Lime
Authors: Narasiah K. Subba , Morasse C. , Lemay J.
Published: March 2019

Laboratory and on-site studies were conducted over a period of 18 months on two wastewater treatment plants. The main objective was the removal of phosphorus. Three coagulants were used: alum, ferric chloride and lime. In the precipitation process, alum was found to react preferentially with polyphosphates, but not with orthophosphates. Seasonal temperature variations in wastewater did not have a detrimental effect on the coagulation and flocculation processes. The molar capacity of alum for precipitating the orthophosphate fraction was greater at the secondary level of treatment than at the primary level. The phosphorus removal efficiency varied between 90 and 95% for all coagulants. For lime, the dosage was relatively high in order to achieve the same degree of dephosphatation, leading to sludge accumulation in the aerated lagoons.
Microbiological Study of the Carboxylation of Phenols by Methanogenic Fermentation: A Summary
Authors: Bisaillon J.-G. , Beaudet R. , Lépine F. , Sylvestre M.
Published: March 2019

An anaerobic consortium was isolated for its ability to degrade phenolic compounds under methanogenic conditions. The addition of proteose peptone to the minimal salt medium was necessary in order to maintain its activity. The consortium was shown to degrade phenol via its carboxylation to benzoate. Potential intermediates of benzoate degradation given as substrates to the consortium suggest that benzoate is transformed to 1-cyclohexene carboxylate and to heptanoate. The carboxylating activity of the consortium is not restricted to phenol but efficiently transforms the ortho but not the meta and para isomers of cresol, fluorophenol and chlorophenol. The carboxylation occurs at the para position relative to the phenolic hydroxyl group. The consortium is composed of seven different morphological forms. Phenol carboxylating microorganisms were evaluated at 1 × l08 − 8 × l09 cells/ml. These microorganisms are probably nonsyntrophic since inhibition of methanogenesis and the presence of hydrogen in the gaseous phase did not prevent the carboxylation of phenol. The carboxylating microorganisms have not yet been isolated but an active consortium containing only five morphological forms has been obtained.
Physical Limnology and Water Quality Modeling of North American Great Lakes
Authors: Murthy C.R. , Schertzer W.M.
Published: March 2019

Physical limnological research relevant to large lake water quality issues conducted in the Laurentian Great Lakes over the last two decades is presented. Particular attention is given to Lake Ontario. Persistent boundary currents are observed near the north and especially the south shore. The coastal boundary layer characteristics are defined as well as coastal upwelling and coastal circulation characteristics, including the occurrence of internal Kelvin wave propagation following major upwelling events. In addition, fundamental turbulent diffusion characteristics, based on large scale experiments and specialized studies, are described.
Physical Limnology and Water Quality Modelling of North American Great Lakes
Authors: Murthy C.R. , Schertzer W.M.
Published: March 2019

Incorporation of physical limnological processes within the water quality/contaminant modelling framework of large lake systems is fundamental for accurate simulation of transport, distribution and pathways of pollutants. Specific examples of water quality/contaminant model applications to the North American Great Lakes are presented with emphasis on models which incorporate physical processes to solve eutrophic and toxic contaminant problems. Examples of circulation and transport model application to lakes and coastal areas as well as thermocline models are briefly described. Water quality models which incorporate such physical limnological processes include eutrophication models, contaminant transport models (river plume, lake and coastal cases). Specific examples are provided primarily from applications in the lower Great Lakes.
Initial Implementation of the Great Lakes Forecasting System: A Real-Time System for Predicting Lake Circulation and Thermal Structure
Authors: Schwab D.J. , Bedford K.W.
Published: March 2019

The Great Lakes Forecasting System is a real-time coastal prediction system for forecasting, on a daily basis, the physical state of each of the Great Lakes for the next two days. Forecast variables include the surface water level fluctuation, horizontal and vertical structure of temperature and currents, and turbulence. The system uses meteorological observations, satellite data, and forecasts from numerical weather prediction models as input. Lake circulation and thermal structure are calculated using a three-dimensional hydrodynamic prediction model. Output from the model is used to provide information on the current state of the lake and to predict changes for the next two days. This information is used by scientists, government agencies, commercial operations, and the public for enhancement of commercial and recreational activity, resource management, and hazard avoidance.

This paper describes system design, data acquisition and analysis procedures, the hydrodynamic model, and sample model output. The initial implementation of the system provides daily nowcasts of system variables for one lake, Lake Erie. Requirements for implementing actual lake forecasts are discussed.
Mixed Layer Models and Their Application to Water Quality Problems
Authors: McCormick M.J.
Published: March 2019

Four one-dimensional models which have been used to characterize surface mixed layer (ML) processes and the thermal structure are described. Although most any model can be calibrated to mimic surface water temperatures, it does not imply that the corresponding mixing processes are well described. Eddy diffusion or "K" models can exhibit this problem. If a ML model is to be useful for water quality applications, then it must be able to resolve storm events and, therefore, be able to simulate the ML depth, h, and its time rate of change, dh/dt. A general water quality model is derived from mass conservation principles to demonstrate how ML models can be used in a physically meaningful way to address water quality issues.
Transfer Function Model for Current to Wind
Authors: Virta J. , Elo A.-R.
Published: March 2019

In some cases it may be useful to study the dependence of physical variables, like the current velocity or the depth of an isotherm in a lake, on the wind velocity from experimental data. In this study a transfer function model is applied to the current velocity vector for three separate cases. The first case concerns the hypolimnetic current in a sound between two basins (surface areas of 26.4 km2 and 52.1 km2) of a large lake in the temperature-stratified situation. In the second case, time series analysis is applied to the oscillatory currents in the hypolimnion of a stratified lake (surface area of 13.6 km2), and the third case concerns near surface currents in a homogeneous lake (surface area of 154 km2). The results of the transfer function may be used for computation of steady-state current due to long periods of constant wind, and also for comparison of measured and computed oscillatory characteristics of current velocity. The results from each of the computations were rather promising.
Operational Model and its Validation with Drift Tests in Water Areas Around the Baltic Sea
Authors: Koponen J. , Virtanen M. , Vepsä H. , Alasaarela E.
Published: March 2019

Three-dimensional (3-D) mathematical models of water currents, transport, mixing, reaction kinetic, and interactions with bottom and air have been used in Finland regularly since 1982 and applied to about 40 cases in large lakes, inland seas and their coastal waters. In each case, model validity has been carefully tested with available flow velocity measurements, tracer studies and water quality observations.

For operational use, i.e., for spill combatting and sea rescue, the models need fast response, proven validity and illustrative visualization. In 1987-90, validated models were implemented for operational use at five sea areas along the Finnish coast. Further validation was obtained in model applications from nine documented or arranged cases and from seven emergency situations. Sensitivity tests supplement short-term validation. In the Bothnian Sea, it was nescessary to start the calculation of water currents three days prior to the start of the experiment to reduce initial inaccuracies and to make the coastal transport estimates meaningful.
Fractal Dimensions and Shape Factors of Digested Sludge Particle Aggregates
Authors: Námer Juraj , Ganczarczyk Jerzy J.
Published: March 2019

In a previous paper, digested sludge particle aggregates were examined by an image analysis system and by a free-settling multi-exposure photographic method. Based on microscopic observations, it was found that these aggregates exhibited the characteristics of statistically self-similar fractals. The experimentally determined terminal settling velocities and 2-D settling shape factors, which described the irregularity of aggregates during the settling operation, were utilized in this work to estimate the parameters of a settling equation in which the fractal geometry of aggregates was incorporated. Based on these equations, the 2-D and 3-D size-density fractal dimension of digested sludge particles were determined.
Partitioning of Heavy Metals in Some Quebec Municipal Sludges
Authors: Ravishankar B.R. , Auclair J.-C. , Tyagi R.D.
Published: March 2019

The process efficiency of metal bioleaching from sewage sludges depends upon various physicochemical characteristics of sludges and the forms in which metals are present in these sludge solids. The aim of this research work was to evaluate the metal speciation in some Quebec sludges with the help of a sequential extraction procedure, in order to better predict the bioleaching process. The distribution of Al, Cu, Fe, Mn and Zn in exchangeable, sorbed, organically bound, carbonate, and residual forms were compared among both undigested and digested sludges. Metal redistribution after aerobic sludge stabilization was also studied.

Results indicate that the organic and residual fractions were the principal metal binding phases. Copper was present mostly in the residual fraction while the other metals were mostly organically bound. Statistical tests showed that metal speciation varied significantly from one sludge to another. In terms of metal distribution pattern observed, these sludges could not be regrouped according to the sludge type, their total solids concentration or their total metal concentration. However, the variation in metal distribution among Quebec sludges was similar to the variation range found in the U.K. and U.S. sludges. The metals showed a tendency to redistribute and move towards the organic fraction in stabilized sludges. In conclusion, the present study shows that sewage sludges of different origins do not have similar metal distribution and hence, the speciation of metals must be considered for each sludge on an individual basis in order to predict their fate during the bioleaching process.
Heavy Metal Content of the Keban Lead Plant Slag and Movement of Metals in Soil of the Surrounding Region
Authors: Rüstem Gül
Published: March 2019

The heavy metal content of the Keban lead plant (KLP) slag, its variation with time under rain and snow, the capacity of the Keban region soil to remove heavy metal ions, and the distribution of these metals in soil were investigated. For this purpose, the dilute acetic acid extraction test of the U.S. Environmental Protection Agency was applied to the slag samples and amounts of heavy metals extracted with hot (80°C) 4 M HNO3 from soil samples at different depths were determined. The concentrations of heavy metal ions in the soil varied with depth, and the heavy metal content of the slag changed with time, showing effects of rain and melt water from snow. From the observed relationships, which take into account the heavy metal content of the slag and the capacity of the soil to remove metal ions leached from the slag, it was concluded that KLP slag from different sites can be applied to land.
Environmental Effects of Aluminum Used in Water Treatment Plants of Rio de Janeiro State, Brazil
Authors: Azcue Jose M. , Malam Olaf , Pfeiffer Wolfgang G.
Published: March 2019

The effect of the extended use of alum on the concentration of aluminum in water treatment was investigated. Water from the Paraiba do Sul-Guandu River (PSR-GR) system, collected after conventional treatment, was analyzed from the six water treatment plants (WTPs). One of the WTPs, the Guandu WTP, supplies water to the city of Rio de Janeiro (11 million inhabitants) with a flow of 40 m3/s. The concentrations of aluminum found were near and sometimes over the values recommended by the World Health Organization (200 µg/L), with an average concentration of 306 µg/L, reaching seasonally maximum values of 877 µg/L at the WTP and 2,100 µg/L in household taps. The discharge of alum sludge back to the river system is the predominant pathway in the aluminum cycling in the study area, followed by sedimentation and enhanced availability to the biota.
Environmental Chemical Behaviour of Metal Contaminants in Aquatic Environments in China
Authors: Liu J.Y. , Lin Y.H. , Mao M.Z.
Published: March 2019

The chemical species of metal contaminants and their transformation in aquatic systems are largely dependent on environmental conditions. This paper reports on some work on metal contamination in a number of rivers in China. Speciation by sequential extraction and some physicochemical processes involving the transformation and transport of metals in the aquatic systems are also reported.
Sunlight Photocatalytic Degradation of o-Chloroaniline
Authors: Daoxin You , Yongsheng Chen , Shugui Dai
Published: March 2019

o-chloroaniline (o-CA) is a priority organic pollutant that exists widely in industrial pesticide wastewater. Recent reviews on the wastewater treatment methods for the pesticide industry indicate that the treatment methods utilized do not always lead to complete degradation of o-CA. The photocatalytic degradation behaviour of o-CA has been studied in the presence of a catalyst. The effects of the kind of catalyst, pH of the solution and the influence of dissolved oxygen have been examined. After treatment, the organic pesticide wastewater with chloroanilines was non-toxic, and chloroanilines were almost completely degraded after a certain period of irradiation (photodegradation up to 98%, COD removal up to 62.6%.) Experiments on photocatalytic degradation of o-CA with sunlight showed a promising route for pesticide wastewater treatment.
Renovated Water Reuse from Rapid Infiltration System
Authors: ZhenBo Duan , ShaoTang Wang Shang , RuQi Li , XureQing Wu , Erjing Gao
Published: March 2019

The use of renovated water from a rapid infiltration system for fish and duck farming was evaluated. It was concluded that the flesh of fish and duck was edible. The use of this approach is beneficial to the environment and economy, especially in developing countries. The production of fish and duck can offset the cost of wastewater treatment in many cases.
Recent Advances in Treatment of Selected Hazardous Wastes
Authors: Bewtra J.K. , Biswas N. , Henderson W.D. , Nicell J.A.
Published: March 2019

Horseradish peroxidase, once activated by hydrogen peroxide, initiates the oxidation of a wide variety of aromatic compounds. The products of this reaction undergo a non-enzymatic polymerization to form water insoluble aggregates which are easily separated from solution. This process shows great promise for removing aromatic compounds from industrial wastewaters which are not efficiently removed through conventional treatment methods. The capability of solubilized horseradish peroxidase in catalyzing the precipitation of phenols from solution in batch reactors is discussed. Studies have been conducted on the biological sulfate reduction process to remove metals from synthetic and actual industrial wastewaters. Under anaerobic conditions, bacteria of the genera Desulfovibrio and Desulfotomaculum produce hydrogen sulfide which reacts with metals to form metal sulfide precipitates. An anaerobic upflow fixed-film reactor with continuous flow was used to treat actual wastewater from a plating plant supplemented with lactate. The results indicate that soluble metals can be precipitated at efficiencies of up to 99%. The rates of organic conversion, sulfate reduction and metal removal have been found to be dependent on the hydraulic retention time.
Improving the Operation of Wastewater Treatment Systems by Automatic Control
Authors: Olsson Gustaf
Published: March 2019

Some basic ideas of process control applied to the activated sludge process are presented. The focus is rather on controller structures than on models. The main reason for the control is to dampen the influence of disturbances and load changes. Due to the wide span of time scales of the process, it is possible to decouple many control actions from each other. Some of the controllers are quite simple and do not require any model, while others are related to quality parameters and are based on model descriptions. By combining simple controllers, more complex structures can be obtained, such as cascaded control and feedforward control. For some control tasks the simple controllers are inadequate. Processes with time-variable parameters present special problems. Since many variables and parameters are not directly measurable, it is valuable to apply estimation techniques in order to obtain calculated variables indirectly. The interdisciplinary character of the problems has to be understood in order to find relevant solutions to the complex control problems.