bluuebunny/crossref_metadata_2025_split huggingface dataset:
Utilization of Oxygen Models in Environmental Impact Analysis
Authors: Snodgrass W.J. , Holloran M.F. 
Published: March 2019

Abstract
A vertical one-dimensional temperature-oxygen model for reservoirs is used to estimate zones of stress on the aquatic environment of a series of reservoirs in Nova Scotia. Application to cold climates necessitated a few novel developments for the temperature model. The oxygen model whose sinks are water column decay and sediment oxygen demand (SOD) is calibrated using under ice measurements of oxygen stocks and laboratory and in situ measurements of a zero-order kinetic model for sediment oxygen demand. These extensive studies are complementary and indicate a winter SOD of 0.1 gm 02/m2/day and a higher summer value. High epilimnetic temperatures coupled with the predicted anoxic zones in lower waters cause a major stress upon fisheries potential. This model provides a tool for determining the effects of different reservoir management strategies upon water quality and for selecting among these strategies.
Sediment-Water Interchange of Copper and Nickel in Experimental Aquaria
Authors: Stokes P.M. , Szokalo A.M. 
Published: March 2019

Abstract
Lake and stream sediments often reflect recent additions of heavy metals before elevations of such elements are detectable in the overlying water. Concentrations of metals in sediments of lakes may be three to four orders of magnitude greater than in the water. While tests of water quality may, therefore, indicate no elevated metal levels in the soluble phase, a water body may still be heavily polluted, with organic and inorganic material in sediments acting as sites for precipitation and adsorption of the metals. The possibility of reentry of sedimented material into the water, due to physical, chemical or biological processes in natural situations, always exists.
Experimental work was carried out on nickel and copper in the sediments of Middle Lake (recently limed to pH 6.5, and fertilized) and of Clearwater Lake (untreated), Sudbury, Ontario, under a variety of physical and biological conditions in aquaria. Results showed that both copper and nickel increased in concentration in water overlying the sediments, eg. in “live” aerobic systems over 28 days total copper in water increased from 0.15 to 0.85 ppm, and total nickel from 0.3 to 3.0 ppm. The pH of the water, initially 6.5, dropped to below 4.0. In sterile anaerobic conditions, total copper decreased slightly, and total nickel remained constant, while pH in this condition initially dropped only slightly, and at 28 days was 6.0. The “live” anaerobic system was intermediate in all these respects.
“Free” copper at lower pH values (measured by differential pulse anodic stripping voltammetry) was predictably equal to total copper (measured by flame atomic absorption or by anodic stripping), but in the sterile anaerobic treatments where pH was 6.0, “free” copper was less than 50% of the total copper. Since ionic copper is believed to be the form toxic to biota, the lowered pH and increased ionic copper in water close to the sediments appears to have serious implications.
Chemosensory Bioassay of Toxicity of Lake Waters Contaminated with Heavy Metals from Mining Effluents
Authors: Thompson B.E. , Hara T.J. 
Published: March 2019

Abstract
The toxicity of natural lake waters contaminated with heavy metals from mining effluents was studied by perfusing water samples through the olfactory organs of Arctic char (Salvelinus alpinus) while recording the olfactory bulbar electrical responses to the standard stimulant, L-serine.
Of the five lake waters tested, only Ross Lake, the closest to the mining-smelting site, showed significant depressing effect on the olfactory response at levels as high as 100 times dilution. Chemical analysis of lake waters revealed that Ross Lake had the highest concentrations of heavy metals; 43 μg/1 Cd, 98 μg/1 Cu, &lt;15 μg/1 Ni and 7720 μg/1 Zn. Single component experiments showed that Cu and Cd are probably responsible for most of the depressive effect.
The depressive effect of natural lake water was less than that of an artificial lake water composed of heavy metals based on the natural lake concentrations. Possible involvement of complex formation of heavy metals in the reduction of their toxicity is discussed.
The Effect of Metallic and Ionic Species on the Performance of a Biological Effluent Treatment System
Authors: Volesky B. , Samak Q. , Waller P. 
Published: March 2019

Abstract
Review of the available results appearing in the recent literature is presented focusing particularly upon the effects of metallic ions such as Cr, Cu, Zn, Cd, Hg, V, Zn, Ni and Co. Some original data involving the effects of Na are presented and discussed. Development of parameters used in evaluating the influence of toxic or inhibitory species on the mixed microbial population of an activated sludge system is of crucial importance and different techniques employed such as BOD-COD-TOC-removal rates, Oxygen Uptake Rate, and others are discussed, showing relative inadequacy of currently applied assays.
From the data available, certain trends can be discerned. There is a definite threshold concentration for each metallic ion, depending on the organic load of the feed. In the order of increasing toxicity to activated sludge systems reflected in lower BOD removals the following metals have been listed as inhibiting factors at concentrations starting from 1 ppm applied on a continuous basis: hexavalent chromium, cobalt, zinc, cadmium, trivalent chromium, copper and nickel.
Metals in combination have not been reported to exhibit any significantly different effects as compared to those observed with individually introduced metallic ions. Tolerance of some activated sludge systems to shock loadings by various inorganic ions and metals is reviewed. The conclusions are of particular importance for estimating the performance of biox systems handling industrial effluents which are likely to contain toxic components of inorganic or metallic nature.
Detergent Phosphorus Legislation: A Technical Appraisal of its Effectiveness
Authors: Budd R.A. , Jones P.H. 
Published: March 2019

Abstract
This literature review provides a technological evaluation of government legislation on phosphate contents in commercially available detergents to decrease P inputs and thereby reduce the rate of eutrophi-cation to receiving waters.
The predicted 50-60% reductions of phosphorus in raw sewage were achieved in the cases studied. This was attributable to regulation of detergent phosphorus. This study reports six years after such legislation was enacted in Canada, a statistical analysis of historical data on plants operated by the Ontario Ministry of the Environment. It illustrated that with 95% confidence the 1976 influent phosphorus concentration has decreased from 33 to 55% of the 1970 influent values.
Decreases in energy consumed and sludge volume indicated that detergent reformulation legislation is not only a very effective interim measure for reducing phosphorus loadings (results being realized immediately) , but provides a cost-effective complementary system to existing phosphorus removal programmes.
The reduction in phosphorus loading to receiving waters is an established fact. However, the impact of decreased P loadings, whether through legal measures or chemical removal, is difficult to quantify because of the many complex variables affecting water quality and algal biomass in aquatic ecosystems.
Catalytic Wet Oxidation of Phenolic Solutions
Authors: Doreau G. , Chornet E. 
Published: March 2019

Abstract
In the present study- the activity and selectivity of three oxidation catalysts were tested in order to reduce the severity of wet oxidation of phenolic solutions. A one litre batch reactor was used and intermittent sampling and analysis of the gaseous and liquid phases was carried out on a routine basis.
The first experiments showed that main intermediates formed during the oxidation reactions were polyphenols, acetic acid and formic acid. Temperatures up to 150°C and oxygen pressures resulting in up to five times the stoichiometric amount of oxygen needed for the total oxidation of phenols were used for the studies.
The work done to date shows Pt/C catalyst superior to CuO/Cr2O3 and Ag/Al2O3 as far as activity and selectivity are concerned. Only the Pt/C catalyst yields a complete oxidation without significant formation of acetic and formic acids.
Effects of benzene, a water soluble component of crude oils, on membrane integrity and ionic content of the green alga Ankistrodesmus falcatus var. mirabilis
Authors: Kauss P. B. , Hutchinson T. C. 
Published: March 2019

Abstract
Experiments were devised to investigate the effects of the aromatic hydrocarbon benzene on the membrane integrity of the green freshwater alga Ankistrodesmus falcatus var. mirabilis. The ability of cells to retain ions (e.g. calcium, chlorine, copper, magnesium, manganese and potassium) when exposed to benzene was used as a measure of cell membrane disruption. Cells were exposed to various dosages of benzene in the light and the dark. Samples removed at pre-determined time intervals were analyzed for the above elements using neutron activation analysis. It was found that, (at dosages greater than ~24 umoles benzene per μl−1 cell volume), the rate of loss of potassium and manganese was proportional to both the benzene dosage and the time of exposure, but not affected by illumination. However, although loss of potassium and manganese from cells was complete after 24h exposure to the highest benzene dosage used (48 μmoles. μl−1) only a fraction of calcium, chlorine, copper and magnesium had been lost. This suggests a difference in the degree that these elements are bound or free in the cells, and that loss of potassium and manganese from cells is a sensitive indicator of cell membrane damage.
Mixing Efficiencies in Full-Scale Anaerobic Digesters by Tracer Methods
Authors: Monteith H.D. , Stephenson J.P. 
Published: March 2019

Abstract
Tracer analyses of the full-scale anaerobic digestion processes as two water pollution control plants revealed that nonideal mixing conditions existed. In both systems, 75% of the total volume of the gas-mixed primary digesters was inactive, significantly reducing the effective hydraulic retention time in one system to approximately 5 days compared to the theoretical mean of 22 days. In the other primary digester, short-circuiting around the actively mixed zone accounted for 61% of the input flow. The fundamental objectives of digestion cannot be realized under these operating conditions. The results prove that greater attention must be given to reactor mixing in the design and operation of anaerobic digesters.
Modeling Nitrate Transport in a Small Upland Stream
Authors: Stammers W.N. , Robinson J.B. , Whiteley H.R. , Kaushik N. K. , Sain P. 
Published: March 2019

Abstract
Swifts Brook, a small headwater stream within the Grand River Watershed in Southern Ontario, originates, during baseflow periods, in a spring with a high nitrate concentration. The spring, which is the principle source of summer streamflow for the brook, has peak flow rates of up to 5.5 l sec 1 in March and April and minimum flowrates as low as 2.8 l sec in August or September. The nitrate concentration in the spring is highest during periods of highest flowrate and lowest in October or November. The mean annual concentrations of NO3 ~*-N in the spring outflow, weighted by flowrate, were 4.3 mg SL * in 1975 and 4.1 mg l in 1976.
During dry summer conditions a two km reach of the main channel, beginning at the spring, receives no surface flow contributions from ephemeral tributaries. Stream processes in this portion of the stream channel were studied in detail (Robinson et al. 1977). The location of the spring and study reaches are shown in Fig. 1. For this reach, the stream water surface width varied from 0.7 to 3.8 meters and the water depth and average velocity vary from 0.08 to 0.23 meters and 0.004 to 0.05 m sec respectively.
Fecal Sterols: Their Distribution in Water and Resultant Significance
Authors: Switzer-Howse K.D. , Dutka B.J. 
Published: March 2019

Abstract
Samples of raw sewage and clarifier effluent were collected to study the effect of (!) centrifugation, (2) sonication, and (3) sonica-tion followed by centrifugation, on the distribution of fecal sterols within a sample, as compared to untreated samples. Samples were analyzed by GLC immediately after treatment. The procedure was repeated on samples which were stored for 1 week at 4°C. Bottles which had been used to store the samples were analyzed to determine whether adherence of fecal sterols to the glass storage container occurred.
Results Indicated that centrifugation of the raw sewage sample produced an average ten-fold concentration of fecal sterols in the sediment pellet as compared to the supernatant, while similar treatment of the clarifier effluent produced an average four-fold increase in fecal sterols in the sediment pellet. Sonication of samples prior to centrifuging did not affect these results significantly. Data obtained from the stored samples showed a similar distribution of fecal sterols upon centrifuging of sample prior to analysis. Analysis of the glass storage bottles (for fecal sterols) showed that the adherence of fecal sterols was not a problem.
Field Observations of Tracer Dispersion Under Natural Flow Conditions in an Unconfined Sandy Aquifer
Authors: Sudicky E.A. , Cherry J.A. 
Published: March 2019

Abstract
ABSTRACT An exceptionally detailed field determination of the solute transport parameters was performed in an unconfined sandy aquifer near an abandoned landfill at the Canadian Forces Base at Borden, Ontario. The test site is located above the contaminant plume originating from the landfill. The aquifer consists of slightly stratified sands with minor laminations. A chloride salt solution was injected into a two m3 volume of aquifer about one meter below the water-table and then migration of the tracer occurred under the natural hydraulic gradient. The migration of the chloride pulse was monitored in detail using a three-dimensional array of bundle-type multilevel samplers. Hydraulic head measurements in the zone of transport were obtained from a network of miniature piezometers. The test results demonstrated the influence of zones of local aquifer heterogeneity on solute migration rates and the ability of a porous medium to disperse solutes in these zones. Different rates of groundwater flow between a fast and slow transport zone caused the pulse to split into two halves. Each half was found to be Gaussian in shape in accord with the classical theory of solute transport. The measured chloride distributions closely fit an analytical solution of the advection-dispersion equation. Dispersivity values for chloride obtained from the analytical solution increased with mean travel distance in the groundwater flow domain, which suggests that calibration of a deterministic model at one spatial scale may lead to erroneous predictions when applied to a different scale. From this it is concluded that, if deterministic models are to yield useful predictions of contaminant migration, it will be necessary to establish scaling functions from studies of the variability of transport parameters in a wide range of hydrogeological settings.
Comparison of Methods and Concepts Used in Assessing the Extent of Water Pollution in a Canadian Shield Lake
Authors: Moore J.W. , Sutherland D.J. , Beaubien V.A. 
Published: March 2019

Abstract
The relative merits of several different methods and concepts used in the assessment of water pollution were determined during 1977 in Giauque Lake, situated in the Northwest Territories. The lake had become polluted through the operations of a gold mine, which discharged mercury-1aden tailings and other waste material directly into the water. The concentration of mercury in the sediments decreased as the distance from the mine increased. Concentrations of over 5000 µg/kg (dry weight) were found in the immediate vicinity of the tailings fan, whereas, at distances of 1.0 and 1.3 km from the fan, the level of mercury averaged 1000 and 100 µg/kg, respectively. Because an extensive series of bottom samples were collected, it was possible to designate a well-defined zone of chemical contamination in the sediments. There was a strong, negative correlation between the density of benthic invertebrates in the sediments and the level of mercury contamination. Consequently, a zone of influence paralleling that outlined for the chemical analysis could again be delineated. However, the diversity index and species composition of the benthic communities gave no indication of environmental impact. Since the waters of Giauque Lake contained extremely low levels of heavy metals, the diversity, species composition and density of zooplankton communities were not useful in assessing the zone of influence. It is concluded that direct determinations of the concentrations of heavy metals in the sediments and the density of benthic organisms were the only effective means of monitoring the extent of pollution in the lake. Other traditional methods, such as diversity indices and the species composition of the fauna and the measurements of water quality gave little if any indication of contamination.
Improvement of Clarifier Performance
Authors: Cordoba-Molina J.F. , Hudgins R.R. , Silveston P.L. 
Published: March 2019

Abstract
Clarifier operation is a fluid flow problem which, up to now, has been viewed in terms of homogeneous fluid concepts. However, flow in clarifiers is stratified since its density decreases with height. This stratification gives rise to phenomena that do not exist in homogeneous fluids. These appear to cause mixing which decreases removal efficiency. In this paper, we show how by using downstream contractions in the flow, it is possible to virtually double the capacity and increase the removal efficiency of clarifiers.
The Impact of Industrial Shock Loading on Selected Biocoenoses in the Lower Welland River, Ontario
Authors: Dickman M. , Smol J. , Steele P. 
Published: March 2019

Abstract
A baseline for biological and chemical water quality conditions was established for a section of the Welland River which daily receives large quantities of nitrogenous and carbonaceous inorganic compounds from Cyanamid of Canada Limited.
Specific conductivity transects across the river at various locations indicated that the effluents discharged clung to the north shore of the River. In addition, simultaneous continuous conductivity measurements from above and below the plant were made during five one-week long periods and the results temperature corrected. At the upstream site conductivity never exceeded 400 limhos/cm while below the plant it averaged 950 umhos/cm with sporadic peaks exceeding 1 0,000 umhos/cm.
Epiphytic diatoms scraped from typha stalks growing in the water at sites above the plant were dominated by Nitzschia dissipata, while the pollution tolerant diatom, Nitzschia palea, dominated at the majority of the downstream sites. In addition, blue green algae replaced filamentous green algae below the plant.
Higher aquatic plants reflected a very distinctive zonation pattern. No higher aquatics were found growing in the water in the impact zones immediately below the effluent outfalls. The first macrophytes to appear downstream of these sites were cattails, while further downstream the arrowheads (sagittaria) and later the submersed macrophytes, such as Elodea and Myriophyllum appeared.
No resident fish population occurred along the north shore downstream of the plant. Shiners and other small transient fish species which were observed entering the effluent plume near Thompson's Creek during periods of shock loading went "belly-up" within one minute indicating the extreme toxicity of these waters.
Variation in Sludge Settleability with Temperature
Authors: Henry J.G. , Salenieks E.E. 
Published: March 2019

Abstract
This study examined the effect of temperature on the settleabi1ity of activated sludge at various organic loading rates. Five completely mixed, bench-scale, activated sludge plants, operating under similar conditions at 5, 10 and 19°C, were continuously fed diluted, settled sewage supplemented with carbohydrate (sucrose). Hydraulic loading rates, MLSS and pH were maintained at constant levels during the experiments to eliminate these factors are variables. Dissolved oxygen was kept in excess of 3 mg/1 so that it would not be a limiting factor. Sludge Volume Indices (SVI ) and zone settling velocities were used to indicate changes in sludge settleability.
Microscopic examination of the activated sludge indicated significant differences in the morphological features of filamentous microorganisms present at the two temperature extremes. At 19°C, the predominant forms were characterized by long curving trichomes, occasionally falsely branching, containing short cylindrical cells. At 5 °C, much smaller straight filaments, composed of long, narrow, rod-shaped cells appeared to be the principal microorganisms responsible for bulking. Various other filamentous forms were always present at each of the temperatures studied.
Stirred sludge settling tests of moderately bulking sludges generally exhibited much higher settling velocities and lower SVI's than unstirred bulking samples. However, extremely filamentous bulking sludge exhibited comparable stirred and unstirred settling velocity and SVI values. The standard SVI test was found to be an inadequate indicator of the extent of bulking when trying to correlate the SVI failures from bench-scale performance with the results from continuous units. Lower temperature had no appreciable effect on COD removal efficiency as long as bulking did not cause a loss of solids in the effluent. However, results suggested that less than half the organic load could be accepted at 5°C, that could be handled at 19°C, before filamentous bulking occurred. A plot of loading versus temperature for various SVI's provided a visual indication of the safe loading limit below which bulking was unlikely to occur. The study clearly demonstrated that temperature can have a significant effect on sludge settleability.
Volatilization Rates of Organic Contaminants from Rivers
Authors: Mackay D. , Yuen T.K. 
Published: March 2019

Abstract
A review is first presented of the present state of knowledge concerning the volatilization of organic contaminants from rivers. A series resistance model is derived which enables the volatilization rate to be calculated from a knowledge of river bulk resistance and the air and water near-interface resistances. The importance of Henry's Constant in determining the prevailing volatilization regime is demonstrated. It is shown that the considerable body of information on reaeration rates and particularly the more recent development of the Rathbun hydrocarbon-dye tracer technique provide valuable data on liquid phase resistance. The flux equation is coupled to the river mass flow balance to give an expression for contaminant concentration decay as a function of time or distance of flow. The feasibility of artificially aerating a stream to enhance volatilization is discussed and feasibility shown to be restricted to compounds of high Henry's Constant, except possibly in the presence of ice when volatilization rates may be reduced to undesirably low levels. The rate of sorption in reducing volatilization rate is discussed and quantified. Comparison between the few available literature data and the derived equations shows satisfactory agreement.