bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical Equilibrium Data Bases and Tools for Calculating Zinc Sulfide Geochemistry in Freshwater Sediments and its Toxicity
Authors: McMahon J.A. , Snodgrass W.J. 
Published: March 2019

Abstract
This paper evaluates chemical modelling tools, thermodynamic equilibrium data, and field data appropriate for estimating the concentration of zinc and other relevant metals in freshwater sediments. To identify the expected primary zinc species, a literature search was completed which summarized the available knowledge. Within the available literature, the largest variability was found in the metal sulfide system. A critical review of the data, together with application of a consistent procedure for incorporating primary sulfide constants in a thermodynamic data base, was used to reduce the variation in the reported values for the solubility and complexation constants. The primary soluble forms of zinc, iron and lead for two field sites impacted by zinc discharges (Hamilton Harbour impacted by steel mill and treated urban wastewater discharges and a base metal mine impacted site) were ZnOHHS0, Fe2+ and Pb(HS)3, respectively. Implications of this work for the evaluation of aquatic toxicity in aquatic sediments are also presented. The chemical equilibrium model used in this study—solid phase speciation measurements—and a sediment phase mass balance model can form the basis for determining the toxicity status of a system due to zinc contamination.
Burlington Bay, Lake Ontario: Its Paleolimnology Based on Fossil Ostracodes
Authors: Delorme L. Denis 
Published: March 2019

Abstract
The history of Burlington Bay for the last 8,400 years has recorded two significant changes in its environment. The first occurred about 2,540 years ago, resulting from a change in mean annual temperature. This, in turn, changed the chemistry of the bay water. The second change occurred about 125 years ago (ca. 1865 A.D.). This time, it was the impact of agricultural practices and industrialization. Agricultural practices caused the lake to become eutrophic. This rapidly (within 40 years) changed the bottom water oxygen conditions to anaerobic. Industrialization had an impact on the fauna and the flora. Some fauna became locally extinct while some phytoplankton became deformed.
Risk Assessment of Copper-Contaminated Sediments in the Tsolum River Near Courtenay, British Columbia
Authors: Deniseger John , Kwong Y.T. John 
Published: March 2019

Abstract
Acidic drainage originating from an abandoned copper mine on Mt. Washington has given rise to elevated dissolved copper concentrations that may threaten aquatic life throughout most of the Tsolum River watershed on central Vancouver Island. Only sediments in the upper portion of the watershed near the mine site, however, have tested acutely toxic to the amphipod Hyalella azteca. Despite evidence of mechanical transport of copper up to 18 km down-stream from the mine site, the sediment-bound copper in the lower watershed appear to be highly stable such that the copper-rich sediments are unlikely to become a secondary source of dissolved copper. In addition to copper attenuation through dilution, extensive wetland areas in the lower watershed contribute significant amounts of dissolved organic carbon that form stable complexes with copper and ameliorate the toxic effects of dissolved copper. These observations imply that successful reclamation at the mine site is probably sufficient to assure acceptable water quality farther downstream.
Minimizing Combined Sewer Overflows in Real-Time Control Applications
Authors: Pleau Martin , Methot François , Lebrun Andrée Moïra , Colas Hubert 
Published: March 2019

Abstract
An approach to design and operate real-time control system for combined sewer overflows is proposed. The methodology is based on nonlinear programming with the peculiarity that all the constraints are linear. The problem definition guarantees a non-null optimization space while preserving the physical and dynamical constraints of the state variables. The nonlinear cost function allows standard control objectives to be met and simulation of the behavior associated with storage facilities and actuators. The linear flow dynamic constraints are defined to simulate flow attenuation as well as to reject unknown disturbances.
Fluorides in Wastewater Discharges: Toxic Challenges to the St. Lawrence River Biological Community
Authors: Wallis Peggy , Gehr Ronald , Anderson Perry 
Published: March 2019

Abstract
This literature review examines the risk to fluvial organisms of fluoride released to the St. Lawrence River by the Montréal Urban Community waste-water treatment plant. The following key points are presented regarding the behaviour of fluoride in aquatic systems: fluoride is not removed by primary sewage treatment methods; fluoride from the treatment plant is rapidly diluted to background levels; aquatic plants do not accumulate significant levels of fluoride; fluoride is generally sequestered in the shell/exoskeleton/skeleton and skin of animals and released via the urinary system; fluoride ion is not very toxic in aquatic systems; there is rarely a large difference between acute and chronic (or lethal and sublethal) threshold levels of fluoride in aquatic systems; the most sensitive aquatic organisms are trout and fingernail clams; finally, the only significant evidence of synergistic action is with aluminium. It is concluded that fluoridation of the city of Montréal’s drinking water would not pose any significant additional risk to the biological community in the receiving waters of the St. Lawrence River.
Extending Retention Times in a Stormwater Pond with Retrofitted Baffles
Authors: MATTHEWS R.R. , Watt W.E. , Marsalek J. , Anderson B.C. , Crowder A.A. 
Published: March 2019

Abstract
Dye-tracing experiments performed in a stormwater pond in Kingston Township, Ontario revealed low average retention times, mainly due to the small size of the pond. However, simulations of the pond flow regime using a numerical model indicated irregular circulation patterns, resulting in short-circuiting and dead zones in the pond. Installation of baffles as a retrofitting measure increased the length-to-width ratio of the flow path in the pond from 1.5:1 to 4.5:1 and corrected the observed flow regime problems. Results of dye-tracing studies performed after the retrofit demonstrated an increase in retention times with a reduction in the speed and volume of short-circuiting flow, and a decrease in wind generated flow patterns due to the installation of the baffles. In addition, an increase in the hydraulic efficiency of the pond (defined as the ratio of measured to volumetric retention times) from 0.65 to 0.86 has been observed. An increase in pollutant removal through sedimentation processes has been inferred from a comparison of retention time distributions measured before and after baffle installation.
Modelling, Design and Optimization of a Combined Sewer Overflow Treatment System
Authors: Gall B. , Averill D. , Weatherbe D. 
Published: March 2019

Abstract
A process modelling and simulation program is being developed as part of a pilot-scale study of satellite treatment options for the control of combined sewer overflows (CSOs). The initial objectives are (1) the development of mathematical models for satellite wastewater treatment processes; (2) the implementation of these models in a computer simulator; and 3) the application of these models to provide a preliminary design of a full-scale CSO treatment facility that will satisfy the local regulatory agency. Results to date show that the models and simulation algorithms constitute a useful planning level tool for investigating CSO control options. The results also indicate the direction of further model development work.
Real-Time Control of Combined Sewer Overflows in Hamilton-Wentworth Region
Authors: Stirrup M. , Vitasovic Z. , Strand E. 
Published: March 2019

Abstract
The Regional Municipality of Hamilton-Wentworth operates and maintains a large combined sewer system in the Great Lakes basin. During dry weather and small storm events, two large interceptor sewers convey all sanitary and storm flows to the Woodward Avenue wastewater treatment plant. Larger rainfall events, specifically high intensity summer thunderstorms, generate flows which exceed the design capacity of the sanitary interceptors and result in combined sewer overflows to Hamilton Harbour and Cootes Paradise, which ultimately discharge to Lake Ontario. The Region is implementing a comprehensive program for reducing the pollution caused by these overflows. This program includes the construction of several off-line detention storage facilities and the implementation of a real-time control system for combined sewer overflow reduction. Real-time control will enable maximum utilization of the storage available within the combined sewer network and help reduce the frequency and volume of combined sewer overflows. New hydrologic and hydraulic simulation models have been specially developed for this project to help identify, test and implement optimal real-time control strategies. This paper discusses some of the more important aspects related to the design and implementation of the Region’s real-time control system, and focuses mainly on the development of these hydrologic and hydraulic simulation models.
Systemic Barriers to the Restoration of Aquatic Ecosystems
Authors: Ellsworth J. 
Published: March 2019

Abstract
An ecosystem perspective is interdisciplinary and holistic, recognizing the interconnections among ecosystem components. The ecosystem approach incorporates social, economic and environmental elements into its definition (Environment Canada 1995). In instances where ecosystem initiatives fail to generate the body of public and political support necessary to address complex issues, barriers can often be found in the ecosystem initiatives themselves. Systemic barriers to the restoration of aquatic ecosystems are generated by the reluctance of some initiatives to go beyond pure sciences and an inability to integrate social, economic and environmental interests. It is common practice to allow the issues at hand to define the scale of an ecosystem initiative. Experience has shown that the issues at hand can also define the appropriate level of engagement. This paper explores Level 3: Community-Based Ecosystem Initiatives and the qualities that enable Level 3 initiatives to avoid and overcome systemic barriers to the restoration of aquatic ecosystems.
The Sewage Issue in Hamilton Harbour: Implications of Population Growth for the Remedial Action Plan
Authors: Charlton Murray N. 
Published: March 2019

Abstract
Much work remains to be done in the implementation and restoration of the beneficial-use phase of the Great Lakes Remedial Action Plans. As plans were being made to reduce nutrient loads at many Areas of Concern, other plans to accommodate population growth were occurring. Population growth has the potential to slow or reverse progress in eutrophication control. A recent proposal to expand one of the local sewage plants without enhancing the treatment level caused a review of Remedial Action Plan goals and water quality responses in Hamilton Harbour. Data on Hamilton Harbour show that phosphorus in the water responds well to load reductions. Moreover, the response of water quality indicators, chlorophyll and Secchi transparency is consistent with expectations of the Organization for Economic Cooperation and Development worldwide relationships. Thus, there is little doubt that proposed expansion of the sewage treatment plant would harm the harbour or that the Remedial Action Plan goals can be achieved by nutrient load reductions. A new proposal to discharge the treated sewage into Lake Ontario instead of the harbour is discussed.
Sediment Resuspension and Dissolved Oxygen Levels Associated with Ship Traffic: Implications for Habitat Remediation
Authors: Irvine K.N. , Droppo I.G. , Murphy T.P. , Lawson A. 
Published: March 2019

Abstract
Many of the Great Lakes Areas of Concern include harbours and navigable channels that experience disturbance of bed sediment due to the passage of large ships. Sediment resuspension due to ship passage may impact efforts to restore habitat and remediate contaminated bed sediment through in situ treatment. To examine the impacts of ship passage, water column profiles of temperature, pH, turbidity and dissolved oxygen, as well as suspended sediment samples, were taken at varying distances behind ships entering an industrial slip area of the Hamilton Harbour Area of Concern during the summer of 1995. Weekly water column profiles and suspended sediment samples also were collected at three sites in the slip area and a harbour control site to characterize ambient water quality. Ship passage significantly increased turbidity above ambient levels due to sediment resuspension, although the increase was less in the deeper areas of the slip. Levels of turbidity and suspended sediment concentration associated with ship passage exceeded that recommended for a moderate level of fish habitat protection. In association with the increased turbidity, levels of dissolved oxygen declined and often were less than 5 and 6.5 mg L-1, the Canadian Water Quality Guideline for later life stage warm and cold water fisheries, respectively. Based on the sample data and in situ flume experiments, the estimated depth of bed erosion due to a ship passage ranged from 1 to 8 mm. The impacts of sediment disturbance due to a ship passage should be considered when selecting and designing appropriate sites and technologies for remediation.
Hydrogeochemistry of Toxic Elements in Urbanized Geotechnical Systems
Authors: Volkov S.N. 
Published: March 2019

Abstract
In urbanized geotechnical systems (UGSs), the majority of problems related to the ecological hydrochemistry of Cd, Pb, Ni and other heavy metals are the result of emergent characteristics of a system as a whole as opposed to individual pollution sources. In petrochemical UGSs, pollution of the environment from compounds containing methylating or alkylating agents results in an increase in the mobility of Cd, Pb, Ni, Cr and As. This process is controlled by environmental and microclimatic factors rather than by pollution sources. Under conditions of predominant dust and element effects, geo-chemically paradoxical associations of Cd with Ni, Mn and Cr can be formed in the main life support media in mining and metallurgical UGSs. Uncontrolled processes of hydrochemical interactions take place in complex multifunctional UGSs, leading to a change in speciation of heavy metals, particularly cadmium. This report is part of a 5-year study of the geotechnical systems in the Urals.
Manganese Greensand for Removal of Arsenic in Drinking Water
Authors: Subramanian K.S. , Viraraghavan T. , Phommavong T. , Tanjore S. 
Published: March 2019

Abstract
The present study was initiated to identify treatment techniques suitable for the removal of As from small community groundwater supplies below the current interim maximum acceptable (IMAC) concentration of 25 µg/L prescribed in the Guidelines for Canadian Drinking Water Quality. The effectiveness of manganese greensand filtration (MGSF), including the effect of Fe(II) in the influent, was studied in batch (intermittent) and column (continuous) modes. Batch studies based on the Freundlich adsorption isotherm model showed that the percent removal efficiency of arsenic by MGSF to the IMAC value was 60 for 24-h equilibration. Column studies gave an overall percent removal efficiency of 41. However, in the presence of Fe(II), especially at an Fe/As concentration ratio of 20, manganese greensand gave an overall efficiency of 83% and a throughput volume of 1,440 L. Results showed that at a Fe/As ratio of at least 20 and in the presence of Fe(II), manganese greensand is capable of removing As to below the IMAC value, under continuous mode of operation and when the influent As concentration is &lt;200 µg/L.
Created and Restored Marshes in the Lower Fraser River, British Columbia: Summary of their Functioning as Fish Habitat
Authors: Levings CD. , Nishimura D.J.H. 
Published: March 2019

Abstract
Ecological comparisons of transplanted, natural (reference) and disrupted (unvegetated) marsh sites on the Fraser River estuary, British Columbia, were conducted between 1991 and 1994. The study examined vegetative biomass and cover, invertebrate abundance, fish abundance, fish residency, fish food, and submergence time for the three habitats. Standing crop biomass at three transplant sites was within the range of values for reference sites, but was much lower at an unstable site where sediment slumping had occurred. The percent cover of Lyngbyei's sedge (Carex lyngbyei) in eight transplant sites was 0.05) was observed among marsh sites when chum salmon (Oncorhynchus keta) and chinook salmon (O. tschawytscha) fry abundance were compared. However, chinook and sockeye smolt catches were significantly different (p&gt;0.05) was observed among marsh sites when chum salmon (Oncorhynchus keta) and chinook salmon (O. tschawytscha) fry abundance were compared. However, chinook and sockeye smolt catches were significantly different (p&lt;0.05) among marsh sites and were usually higher at disrupted sites. In nine sites in the North Arm and Deas Slough area chum fry residency was examined. At one transplant site (DEI) marked chum fry were caught up to 48 h after release. No fry were caught 1 h after release at a transplant site (Dll) and a disrupted site (DE4). At the remaining sites, fry were caught up to 1 and 3 h after release. At all sites, over 80% of the total number of food organisms examined in chum fry stomachs were harpacticoid copepods. Mean submergence time for reference marshes ranged from 33.2 to 50.7%, but for transplanted sites the value ranged from 26.4 to 60.1%. Our study shows that numerous factors need to be examined in determining if restored marshes will function as natural habitats. The development of a standardized set of reference criteria would assist in evaluating whether or not transplanted marshes are functioning as designed.
Uptake and Bioconcentration of 2,2′,4,4′,5,5′-Hexachlorobiphenyl by Lotic Periphyton
Authors: Sallenave R.M. , Day K.E. 
Published: March 2019

Abstract
Laboratory experiments were conducted to examine the uptake and bioconcentration of 2,2′,4,4′,5,5′-hexachlorobiphenyl (HCBP), a model hydrophobic organic compound, in lotic periphyton. The instantaneous rate of uptake and bioconcentration factor (BCF) were determined by following the time course of uptake of 14C-HCBP in periphytic communities established on glass slides. The rate of accumulation was highest in the first 3 hours, and steady state was reached within 8 days. The bioconcentration factor on a dry weight basis (BCFd) averaged 21,000. The results of a depuration experiment indicated that HCBP desorbed from periphyton, but at a much slower rate than its adsorption. The results support the hypothesis that the mechanism of uptake of HCBP in periphyton is a rapid surface sorption followed by a much slower transfer into lipids, and that sorption is largely dependent on the surface area available. The results of this study suggest that lotic periphyton provide a large surface area for adsorption and uptake of persistent hydrophobic compounds such as HCBP and, depending on the extent of grazing pressure, could greatly influence the fate and transport of these compounds in lotic systems.
CTMP Wastewater Treatment Using a Rotating Biological Contactor
Authors: Mathys R.G. , Branion R.M.R. , LO K.V. , Anderson K.B. , Leyen P. , Louie D. 
Published: March 2019

Abstract
Studies on the treatment of CTMP mill wastewater were done using a laboratory-scale rotating biological contactor (RBC). Analysis of the wastewater is given. The effects of organic loading rates in the range 0.007 to 0.033 kg BOD m-2 day1 (0.012 to 0.055 kg COD m-2 day-1) and temperature (20 and 31°C) on the percent removal of BOD and COD are presented. Average BOD (COD) removals ranged from 70% (46%) at 20°C to 86% (72%) at 31°C. The acetic acid content of the wastewater was almost completely biologically oxidized in the RBC and very little acetic acid volatilization was observed. Sulfite and sulfide compounds tended to be oxidized to sulfate compounds during the RBC treatment. Over the range of dissolved oxygen (DO) concentrations (0.3 to 2.0 mg/L) measured in the RBC trough, DO appeared to have no effect on BOD removal, even though some of these DO levels were very low. The discs carried wet microbial biofilms of the order of 0.5 kg m-2. Biomass sloughed off the discs at a rate that was approximately 0.04 kg m-2 day-1.
The Effect of Ambient Concentrations of Chlorate on Survival of Freshwater Aquatic Invertebrates
Authors: Dosdall L.M. , Goodwin L.R. , Casey R.J. , Noton L. 
Published: March 2019

Abstract
Chlorate (ClO3-) is present in some pulp and paper mill wastewater as a byproduct of the use of chlorine dioxide in the bleaching processes. Chlorate is harmful to some species of algae and consequently research was undertaken to determine its impact on survival of freshwater aquatic invertebrates. Five species representing four orders of Insecta (Plecoptera: Isoperla transmarina (Newman); Ephemeroptera: Baetis tricaudatus Dodds and Tricorythodes minutus Traver; Hemiptera: Dasycorixa hybrida (Hungerford); and Coleoptera: Haliplus sp.) were exposed to 5.0, 50.0 and 100.0 mg L-1 chlorate for 10 days. The plecopteran Isoperla longiseta Banks was exposed to 0.5, 5.0 and 50.0 mg L-1 chlorate for 10 days. Survival of specimens exposed to chlorate did not differ significantly from that of the controls. The LC50 for Daphnia magna Straus, determined using the 48 h acute lethality test, was estimated at 3,162 mg L-1. Chlorate levels from a bleached kraft pulp mill in northwestern Alberta that employs 100% chlorine dioxide substitution in its bleaching process ranged from nondetectable. (&lt;0.002 mg L-1) to approximately 75 mg L-1 in effluent at the point of entry to the river system. At 25 and 127 km downstream from the mill, highest levels of chlorate in water samples were 3.25 and 1.00 mg L-1, respectively. Comparisons of laboratory results with field measurements suggest that chlorate discharges from this pulp mill would have no adverse effect on the survival of the aquatic insect species evaluated here.
Occurrence of Alkylphenoxyacetic Acids in Canadian Sewage Treatment Plant Effluents
Authors: Lee Hing-Biu , Weng Jianhua , Peart Thomas E. , Maguire R. James 
Published: March 2019

Abstract
Alkylphenoxyacetic acids such as 4-tert-octylphenoxyacetic acid (OP1EC) and nonylphenoxyacetic acid (NF1EC) are metabolites of non-ionic surfactants derived from the ethoxylation of 4-tert-octylphenol (OP) and nonylphenol (NP). Although the occurrence of OP1EC and NP1EC was suspected in many Canadian sewage treatment plant effluents due to the extensive use of the alkylphenol ethoxylate surfactants and their degradation under sewage treatment conditions, the acids have never been reported due to the lack of authentic standards. In this work, OP1EC and NP1EC were synthesized by the condensation of OP and NP, respectively, with chloroacetic acid in the presence of a base. With these standards, the occurrence of OP1EC and NP1EC in Canadian sewage treatment plant effluents was confirmed for the first time. The level of OP1EC ranged from 0.18 to 1.2 μg/L and from 0.45 to 6.8 μg/L, in the primary and final effluents, respectively. In contrast, the level of NP1EC in the same sample was much higher and it ranged from 2.4 to 17.7 μg/L in the primary effluents and from 3.2 to 703 μg/L in the final effluents.