bluuebunny/crossref_metadata_2025 huggingface dataset:
Respirometric Evaluation of Comparative Biodegradability of Municipal and Petroleum Refinery Wastewaters
Authors: Mahendraker V. , Viraraghavan T.
Published: March 2019

This study was undertaken to evaluate and compare aerobic biodegradation of petroleum refinery (before API separator) and municipal wastewaters using an automatic laboratory respirometer. Seed activated sludge was acclimated with a small quantity of wastewater under study, in fill and draw type reactors. Relatively high initial substrate to seed biomass ratios of 20 and 15 were used to encourage growth conditions. Each wastewater sample was diluted to five concentrations, and oxygen uptake was recorded till the beginning of the endogenous phase. Oxygen uptake data were analyzed using Monod and Haldane kinetics. Results showed that the refinery wastewater was inhibitory and kinetic data followed only the Haldane equation. However, the municipal wastewater followed Monod kinetics, except when a higher substrate concentration was used. A comparison of the kinetics led to an assessment of relative biodegradability of the wastewaters, which will be useful in understanding the impact of refinery wastewater discharge to municipal wastewater treatment systems.
Biosorption of Chromium by Canola Meal
Authors: Al-Asheh Sameer , Duvnjak Zdravko
Published: March 2019

Canola meal (CM) was tested for its ability to adsorb Cr3+ ions from solutions. It was noticed that a decrease in the CM concentration resulted in an increase of the metal ions adsorbed per unit weight of the meal. The meal adsorbed more metal when the metal concentrations in the solutions were higher. Chromium adsorption increased with temperature between 4 and 50°C. The pH values between 5 and 7 did not have much effect on the adsorption of metal by the meal. Freundlich and Langmuir isotherm models fit the equilibrium data of Cr3+ reasonably well.
Determination of Benzothiazole and Alkylphosphates in Water Samples from the Great Lakes Drainage Basin by Gas Chromatography/Atomic Emission Detection
Authors: Scott Brian F. , Sverko Edward , Maguire R. James
Published: March 2019

Benzothiazole, tri-n-butylphosphate tris(2-chloroethyl)phosphate, tris((β-chloro-propyDphosphate and two isomers of this last chemical were detected in all archived water extracts collected from permanent sampling stations located at Fort Erie, Niagara-on-the-Lake and Wolfe Island. The archived samples initially extracted using a Goulden large sample extractor (GLSE) after centrifuging, were analyzed using gas chromatography/atomic emission detection (GC-AED) for P-, S-, and N-containing compounds. All samples also contained atrazine and metolachlor whose concentrations had previously been determined using gas chromatography/mass spectrometry (GC/MS). The concentration values of atrazine in the 38 archived samples as determined by the AED method were similar to those determined by the GC/MS method. However, the concentrations of metolachlor in the 38 archived samples calculated from the GC/AED generally differed by a factor of 2 relative to concentrations determined for the extracts by GC/MS. The atrazine and metolachlor concentrations determined by GC/AED were in the range 12-141 ng/L compared to 10-89 ng/L determined using GC/MS. The trialkylphosphate concentrations were in the range 5-23 ng/L and the benzothiazole concentrations were in the range 1-10 ng/L. Other archived samples from the St. Lawrence River above and below Montréal also contained the above five trialkylphosphates and benzothiazole, as did fresh samples from the eastern and western basins of Lake Erie. Nonpolar fractions from silica gel cleanup of the St. Clair River sample extracts contained none of the compounds of interest, but the compounds were found in the methanol eluates of the cleanup column material. One sample collected from the middle of Lake Huron contained tris(2-chloroethyl)phosphate. Rain samples collected about Lake Ontario contained benzothiazole and the alkylphosphates.
Zebra Mussels as Biomonitors for Organic Contaminants in the Lower Great Lakes
Authors: Comba Michael E. , Metcalfe-Smith Janice L. , Kaiser Klaus L.E.
Published: March 2019

Zebra mussels were collected from 24 sites in Lake Erie, Lake Ontario and the St. Lawrence River between 1990 and 1992. Composite samples of whole mussels (15 sites) or soft tissues (9 sites) were analyzed for residues of organochlo-rine pesticides and PCBs to evaluate zebra mussels as biomonitors for organic contaminants. Mussels from most sites contained measurable quantities of most of the analytes. Mean concentrations were (in ng/g, whole mussel dry weight basis) 154 ΣPCB, 8.4 ΣDDT, 3.5 Σchlordane, 3.4 Σaldrin, 1.4 ΣBHC, 1.0 Σendosulfan, 0.80 mirex and 0.40 Σchlorobenzene. Concentrations varied greatly between sites, i.e., from 22 to 497 ng/g for ΣPCB and from 0.08 to 11.6 ng/g for ΣBHC, an indication that mussels are sensitive to different levels of contamination. Levels of ΣPCB and Σendosulfan were highest in mussels from the St. Lawrence River, whereas mirex was highest in those from Lake Ontario. Overall, mussels from Lake Erie were the least contaminated. These observations agree well with the spatial contaminant trends shown by other biomoni-toring programs. PCB congener class profiles in zebra mussels are also typical for nearby industrial sources, e.g., mussels below an aluminum casting plant contained 55% di-, tri- and tetrachlorobiphenyls versus 31% in those upstream. We propose the use of zebra mussels as biomonitors of organic contamination in the Great Lakes.
Pilot-Scale Demonstration of DARAMEND Enhanced Bioremediation of Sediment Contaminated with Polycyclic Aromatic Hydrocarbons in Hamilton Harbour
Authors: Bucens Paul , Seech Alan , Marvan Igor
Published: March 2019

In 1992, GRACE Dearborn, Inc. was contracted by Environment Canada to conduct a field-scale demonstration of the DARAMEND bioremediation technology under the auspices of the Great Lakes Cleanup Fund's Contaminated Sediment Treatment Technology Program. The demonstration on approximately 150 tonnes of sediment dredged from Hamilton Harbour was completed by January 1994. Two distinct batches of sediment were treated. One batch of 90 tonnes of sediment, dredged directly from the harbour without any pretreatment, is the focus of this paper. Sediment was received in October 1992 and was treated through to December 1993. Treatment was conducted in an high-density polyethylene-lined treatment cell that was covered by a steel framed greenhouse. The treatment involved amending, tilling and closely controlling the sediment water content. In approximately 300 days of treatment, the level of total polycyclic aromatic hydrocarbon contamination was reduced from approximately 1,000 µg/g to 100 µg/g, corresponding to a destruction and removal efficiency of approximately 90%. Notably, the high molecular weight polycyclic aromatic hydrocarbons (containing 4 to 6 benzene rings) were effectively degraded to concentrations below the Ministry of the Environment and Energy’s Soil Placement Guideline for controlled fill (MOEE 1992). The trend in the data suggest that following addition of DARAMEND amendment and several months of active management, the polycyclic aromatic hydrocarbons would continue to biodegrade as a result of the DARAMEND amendment even without active management of the sediment.
Water Quality Trends in Hamilton Harbour: 1987 to 1995
Authors: Charlton Murray N. , Le Sage Robin
Published: March 2019

A series of water samples and Secchi depth measurements were conducted in Hamilton Harbour between 1987 and 1995. The data indicate little recent improvement in the harbour generally. Detection of real improvements may require high frequency sampling and a more extensive sample grid once a cause for improvement is in place. Some measures, such as chlorophyll and Secchi depth, approach RAP initial goals sometimes during recent years, but algal blooms still occur, which prevent attainment of satisfactory average conditions. The cause of aesthetic improvements in water clarity reported in the media was investigated with sampling along an inshore-offshore transect and intense Secchi measurements in the LaSalle Park area. The data are consistent with a transient clarifying effect of zebra mussels on structures near shore. The need to reduce nutrient loads as recommended in the Remedial Action Plan continues.
Surficial Sediments of Hamilton Harbour: Physical Properties and Basin Morphology
Authors: Rukavina N.A. , Versteeg J.K.
Published: March 2019

Studies of surficial sediments of Hamilton Harbour over the past decade have established the sediment-distribution pattern and its temporal and spatial variation. Data are now available for 226 sites sampled during 10 surveys between 1984 and 1993. They include particle size, particle density, water content, shear strength, magnetic susceptibility and sedimentation rate. The basic sediment pattern consists of inshore sands along the undeveloped north and east coasts, disturbed sandy muds along the industrial south shore, and uniform silty sediments in basin depths of 5–25 m. Sediment grain size is dependent upon both water depth and position in the basin, and grain-size statistics for the past decade indicate that the size pattern has been stable over that time span. Limited data on other physical properties give some idea of their scale but not of their areal or temporal trends. Modern sedimentation rates from 210Pb dating range from 0.067 to 0.222 g cm-2 y-1. The average rate is about five times the presettlement rate from radiocarbon dating of long piston cores and is in agreement with sediment-loading data. Reliable data on rates are difficult to obtain because of extensive disturbance of the southern half of the harbour by shipping, dredging and dumping.
Factors Influencing the Light Environment in Cootes Paradise, Hamilton Harbour, and Other Coastal Marshes of Lake Ontario
Authors: Sager Eric P.S.
Published: March 2019

A common characteristic in many degraded coastal marshes of the Great Lakes is the absence of a submersed macrophyte community. A poor light environment due to high levels of turbidity is one factor which has been implicated in inhibiting their recovery. The overall purpose of this study was to examine the relative impacts of suspended materials on the light environment in turbid areas during the critical period of macrophyte germination and growth and causal factors. It also addresses the components of turbidity, partitioning these into three different types: algae (as measured by chlorophyll a), detritus and inorganic material. Through the use of least squares multiple regression, it was found that suspended inorganic material was playing the largest role in increasing light attenuation at all four sites over the course of the study. It was also found that the majority of suspended solids was made up of inorganic material. The sources of this material are discussed.
Loadings, Dynamics and Response Time of Seven Metals in Hamilton Harbour: Results of a Mass Balance Study
Authors: Diamond Miriam , Ling-Lamprecht Helen W.
Published: March 2019

Steady-state and unsteady-state mass balance models based on the QWASI fugacity/aquivalence model (Mackay 1991; Mackay and Diamond 1989) are used to describe the fate of lead, zinc, copper, cadmium, chromium, arsenic and nickel in Hamilton Harbour. To examine the effect of sediment “hot spots” on chemical dynamics in the harbour, a steady-state model with two sediment segments was developed. Model results indicate that the major contamination sources are land-based; sediments are of secondary importance as a source, and Lake Ontario can play a relatively important role as a diluent in some cases. The correspondence between measured and observed water and sediment concentrations obtained with the steady-state model suggests that average sediment concentrations are supported by present inputs rather than historical loadings. We suggest that a 20% annual loading reduction can decrease the average sediment concentrations of Zn, Cr and Cu to below the “severe effect level” of the provincial sediment quality guidelines in 2 to 6 years. The “lowest effect level” can be achieved within 10 years for As and Ni, and more than 20 years for the remaining chemicals at this loading rate. The results of the two-sediment model are illustrative since input values are uncertain, but are consistent with our understanding of harbour dynamics: the central zone accumulates more chemical and is slower to loose chemical, whereas chemical is lost from the nearshore sediment more rapidly.
Toxicity of Halifax Harbour Sediments: an Evaluation of the Microtox® Solid-Phase Test
Authors: Cook Nancy H. , Wells Peter G.
Published: March 2019

Subtidal sediments were collected in Halifax Harbour, Nova Scotia, in July and August, 1992, to study sediment toxicity and hazards near the proposed location of a sewage treatment plant and outfall. A set of 110 samples from eight stations was evaluated. Interstitial water from surface (0-2 cm) and subsurface (2-4 cm) sediments was analyzed by the Microtox® 100% toxicity test protocol. The sediment particles were analyzed using the Microtox® solid-phase test. Interstitial water from surface and subsurface sediments from all stations was usually non-toxic, compared to a phenol standard. The mean 5 min-EC50 of surface sediments (n=57) was 5,433mg/L; the mean 5 min-EC50 of subsurface sediments (n=50) was 804 mg/L. Toxicity thresholds for the harbour sediments were compared with National Research Council marine analytical sediment reference materials and a selection of natural sediments, and ranked. An experiment with the marine reference sediments (certified for PAHs and trace metals) and their mixtures showed the ability of the solid-phase test to discriminate among different levels of contaminated sediments. Intra- and inter-sample variability in toxicity at different locations in relation to time, sediment depth, sediment properties, and types and concentrations of contaminants was evaluated by multivariate and PCA tech-niques. This laboratory-field study provided insights into the sensitivity, repro-ducibility, significance and discriminatory ability of the Microtox® solid-phase bioassay and its value in the study of complex natural sediment mixtures.
Effects of Sampling Technique on the Determination of Major and Trace Elements on Sediment Pore Water
Authors: Azcue Jose M. , Rosa Fernando
Published: March 2019

Pore water samples obtained by squeezing, centrifuging followed by filtration, and in situ dialysis were compared. The effects of the three methods on the measured concentrations of eight elements (Ca, Fe, K, Mg, Mn, Na, Si and Sr) were studied. Iron and Mn proved to be extremely sensitive to oxygen exposure. Immediate centrifugation followed by filtration under nitrogen yield very similar results for almost all the elements as the in situ dialysis technique. The squeezing technique was the most susceptible to handling variables such as pressure-, oxygen- and temperature-related changes. Whenever possible, we recommend the use of in situ techniques that minimize the sampling artifacts. However, the choice of the technique for sampling sediment pore water should be dictated by the objectives of the study.
Total Mercury and Methylmercury Contents of Insects from Boreal Lakes: Ecological, Spatial and Temporal Patterns
Authors: Tremblay Alain , Lucotte Marc , Meili Markus , Cloutier Louise , Pichet Pierre
Published: March 2019

Mercury (Hg) and methylmercury (MeHg) concentrations in insects from 19 lakes in Quebec (Canada) and Sweden ranged from 550 ng Hgg−1 dry weight (dw). The mean proportion of MeHg to total Hg concentrations depended on the feeding behaviour of the animals, increasing from 35-50% in detritivores-grazers (dipterans, ephemeropterans, trichopterans) to 70–95% in predators (heteropterans, coleopterans, odonates). These differences were attributed to the biomagnification of MeHg in the food web since the MeHg/total Hg ratio in the organisms was not related to their body size. A large part of the overall variability of total Hg (r2=0.57, p=0.0001) and MeHg (r2=0.79, p=0.0001) concentrations in insects was explained by taxonomic differences, probably related to feeding behaviour, and the differences between lakes. MeHg concentrations in chironomids and in odonates were significantly correlated with sediment MeHg contents (r=0.78, p=0.005; r=0.62, p=0.001, respectively). However, our results suggest that animal feeding behaviour and the quality of ingested food are more important in determining MeHg accumulation in insects than either MeHg contents of sediment or atmospheric Hg deposition rates. Our data indicate that the bioavailability of Hg to the lower trophic levels of the food web is determined by abiotic factors and controls contamination of predators at the top of the food chain. Total Hg concentrations in insects increased from spring to fall, from 60–80 ng Hgg−1 dw to 125–175 ng Hgg−1 dw in the detritivore-grazer taxa, and from 88–120 ng Hgg−1 dw to 180–200 ng Hgg−1 dw in the predator taxa. MeHg/total Hg ratios showed little variability from spring to fall and the increase of Hg and MeHg concentrations in insects seemed to be related to enhanced methylation resulting from the rise of water temperature and to the variations in the nature of the food ingested.
A Species Tolerance Index for Maximum Water Temperature
Authors: Wichert Gordon A. , Lin Ping
Published: March 2019

A weighted species association tolerance index with respect to water temperature (WSATI-WT) is based on the final temperature preferendum (FTP) of each of the fish species present in a locale of a stream ecosystem. The WSATI-WT is a measure of the distributional consequences of “behaviour” or habitat selection of an interactive set of species with respect to temperature and extends the indicator species concept to an entire association of fishes. Several relationships were exploited to estimate the FTP of several species for which direct estimates were not available: FTP inferred directly from behavioral responses are found to be related approximately by a 1:1 ratio with optimal temperatures for growth, upper lethal temperatures estimated using ultimate upper incipient lethal temperatures,or critical temperature maximum, are related to the FTP by a straight-line relationship across species (within a limited temperature range). When the WSATI-WT was tested in the field, we found positive relationships between it and maximal summer habitat temperatures. The WSATI-WT can be used with observed maximum summer stream water temperatures to forecast change in index scores from a known reference community structure due to warming.
A Planning Tool for Stormwater Quality Management in Urbanized Areas: the City of Scarborough Case Study
Authors: LI James , Weatherbe Don , Mack-Mumford Derek , D’Andrea Michael
Published: March 2019

One of the many challenges municipalities in the Great Lakes Remedial Action Plan (RAP) areas must face is the lack of a screening tool to determine stormwater quality management options in their urbanized areas. In support of the RAP process, Environment Canada, through the Great Lakes 2000 Cleanup Fund, the Ontario Ministry of Environment and Energy, and the City of Scarborough, commissioned Ryerson Polytechnic University to develop a generic planning strategy for stormwater quality management in urbanized areas. The generic planning strategy comprises five steps: (1) identification of ecosystem and economic goals and objectives; (2) identification of feasible retrofit stormwater management practices (RSWMPs); (3) formulation of alternative stormwater quality management strategies in accordance with a preferred hierarchy of RSWMPs; (4) evaluation of alternative strategies with respect to cost-effectiveness; and (5) selection of a stormwater quality management strategy. To demonstrate the application of the generic planning strategy, a stormwater quality management plan was developed for the Centennial Subwatershed (730 hectares) in the City of Scarborough, which is fully urbanized. Using the generic planning strategy, the recommended stormwater quality plan assumes (1) all the roads in poor condition will be retrofitted with stormwater exfiltration systems as they are reconstructed or rehabilitated; (2) an existing quantity pond will be retrofitted with a water quality function; (3) a new water quality pond will be constructed on a government-owned site; (4) 50% of the feasible residential areas will have downspouts disconnected; and (5) all the roads in the feasible commercial areas will be retrofitted with oil/grit separators. The average annual runoff volume reduction and solids loading reduction of this strategy were estimated to be about 9 and 30%, respectively, and the associated cost was about $1.2 million.
Physical and Chemical Characteristics of Sediments from a Stormwater Management Pond
Authors: Watt W.E. , Marsalek J. , Anderson B.C. , JASKOT C.
Published: March 2019

Physical and chemical properties of bottom sediment and suspended particu-lates were studied at the Kingston stormwater pond. The bottom sediments have accumulated in the pond at an average rate of 0.02 m/year and comprised gravel, sand, silt and clay; the first two materials accumulated only by the inlet and the last two were spread throughout the pond and represented up to 45% and 54% of the total sediment, respectively. The water content of the accumulated sediment ranged from the low of 48% (by the inlet) to the high of 78% (at the outlet), by volume. The assessment of total metals in the pond sediment against the MOEE sediment quality guidelines indicated a gross pollution by Cr, and a marginal-to-significant pollution by Cd, Cu, Fe, Pb, Mn, Ni and Zn. Sequential analysis of sediment samples indicated that 40-90% of the retained metals were in potentially mobile forms. The chemistry of suspended particu-lates, representing silt and clay, was similar to that of the bottom sediment, except in the case of Cr.
Field-Scale Studies of Subsurface Flow Constructed Wetlands for Stormwater Quality Enhancement
Authors: ROCHFORT Q.J. , Watt W.E. , Marsalek J. , Anderson B.C. , Crowder A.A.
Published: March 2019

Two subsurface flow constructed wetlands were tested for pollutant removal performance in conjunction with an on-line stormwater detention pond, in Kingston Township, Ontario. The 4.9 m2 wetland cells were filled with 9 mm limestone gravel, and planted with cattail, common reed and spike rush. Changes in nutrient (total organic carbon, PO43- and NH4+), suspended solids and metal (Cu, Pb, Zn) concentrations were used to assess performance. Contaminant removal occurred through a combination of physical, chemical and biological means. As with any biological system, variation in performance of stormwater wetlands can be expected to occur as a result of fluctuations in contaminant loading, contact time and ambient environmental conditions.

Storm pond effluent was delivered in continuous flow through the wetlands (during baseflow and event conditions), with a detention time of 1 to 3 days. The wetlands were able to maintain removal rates of up to 39% for orthophosphate even during the more severe conditions of fall dieback. Average removal of suspended solids (46%) and dissolved metals (Cu 50%) remained similar throughout all tests. Organic carbon was reduced by less than 10% during these tests.

Low nutrient levels in the pond effluent were supplemented by spiking with sources of carbon, nitrogen and phosphorus during pulsed loading conditions. Daily sampling produced a time series, which illustrated the rates of decline in concentration of nutrients. First order kinetic assimilation rates ranged from 1.7 d-1 for NH4002B to 0.12 d-1 for organic carbon, which were noticeably lower when compared with municipal and industrial wastewater treatment rates.

Three methods of sizing stormwater wetlands (impervious surface area, volumetric load and kinetic reaction rates) were compared using the same design storm and data from this study. From this comparison it was seen that the kinetic sizing approach proved to be the most versatile, and allowed for adaptation to northern climatic conditions and anticipated nutrient loading.
Design and Operation of an Aerobic Biological Filter for the Treatment of Urban Stormwater Runoff
Authors: Anderson B.C. , Caldwell R.J. , Crowder A.A. , Marsalek J. , Watt W.E.
Published: March 2019

The primary objective of this research is to develop a field-scale submerged aerobic biological filter (SABF) system for the treatment of urban stormwater runoff. This could be either directly through the introduction of raw runoff to the system, or indirectly by using effluent from a stormwater detention pond as the contaminant source (in a post pond configuration). The SABF influent in all phases of the research was collected from the outlet of a stormwater management pond, constructed in 1982 to provide runoff quantity control for an urban shopping mall complex. This on-line pond also receives runoff from the upstream suburban and rural connected areas, as well as base flow, with a total catchment area of 4.4 km2 (440 ha). Continuous development in the catchment area and the unfavourable shape of the detention pond, have resulted in very poor quantity and quality control. The SABF research was therefore initiated to provide additional cost-effective quality control for this overloaded system.

A number of research phases have been undertaken. The first phase involved development of a bench-scale laboratory SABF, which was used to examine the treatment processes and to establish operating parameters for the system. The second phase used these preliminary results to design, construct, install and assess the operation of a field-scale unit at the stormwater pond site. A third phase has involved long-term operation of the field system, and detailed examination of the influence of operational variables on system performance. This paper summarizes the findings from the lab-scale research and the first phase of field filter operation. The results indicate that this biotechno-logical treatment system may be suitable for the proposed application.
Vortex Separation Technology
Authors: Field Richard , Averill David , O'Connor Thomas P. , Steel Paula
Published: March 2019

Several types of vortex separators have been developed during the last 30 years. Their major function has been to provide both flow regulation and settleable solids concentration for the control of combined sewer overflows (CSOs). A variety of opinions have developed regarding the application of these technologies, ranging from overwhelming support to reservations of their effectiveness. The performance of vortex devices depends on the settling velocity distribution of the particles in the wastewater. When correctly installed with other controls in combined sewer or separate stormwater systems, vortex devices can play an important role in the control of pollution from CSO and stormwater discharge. Reliable determination of performance depends principally upon accurate sampling techniques, suspended solids and other pollutant analyses, and the settling velocity distributions of the influent and effluent. Simultaneous flow rate measurement, synchronized to sampling time, is also necessary. This paper discusses design, application and evaluation of swirl/vortex technologies as part of CSO and stormwater pollution control systems.
Restoration of an Interior Lake Ecosystem: the Kootenay Lake Fertilization Experiment
Authors: Ashley Ken , Thompson Lisa C. , Lasenby David C. , McEachern Laurie , Smokorowski Karen E. , Sebastian Dale
Published: March 2019

Kootenay Lake, B.C. (395 km2), has experienced a series of major perturbations in the past 50 years, resulting in the 1980s’ collapse of South Arm kokanee salmon stocks and a dramatic decrease in the abundance of North Arm stocks. Historical data indicate the collapse was due to reservoir construction together with subsequent impoundment and nutrient retention on both main inflow tributaries (Kootenai and Duncan rivers) to Kootenay Lake, combined with the introduction of an exotic mysid shrimp which is an efficient competitor with kokanee for zooplankton. Nutrients (47.1 t of P and 206.7 t of N) are now being added annually to the 174 km2 North Arm of Kootenay Lake (271.3 mg-m-2 P and 1,190.5 mg-m-2 N) in a 5-year (1992-96) experiment with the goal of restoring historical kokanee salmon biomass and productivity. The concentration of total phosphorus in the North Arm currently ranges from 4–10 µg-L-1 P, which indicates oligotrophic to mesotrdphic conditions, whereas the concentration of dissolved inorganic nitrogen remains in the oligotrophic range (i.e., <200 mg L-1 N) throughout the year. The seasonal mean zooplankton density observed in 1994 was higher than in 1992 and 1993, and similar to the highest densities observed from 1972 to 1984. Cladocerans comprised about 7.5% of the zooplankton in the North Arm in 1994, 12% in 1993 and 7.5% in 1992 as compared with less than 5% between 1949 and 1991. Combined North Arm kokanee escapement (Lardeau River and Meadow Creek) was 1.25 million fish in 1994 and was the highest observed since 1986, but lower than some escapements observed in the 1970s. Kokanee spawner size and fecundity have also increased. No significant trends have been observed in the Gerrard rainbow trout population. To date, the fertilization experiment has been successful at increasing the abundance of clado-ceran zooplankton and restoring kokanee populations in the North Arm of Kootenay Lake.
Water Quality Improvements during Hypolimnetic Oxygenation in Two Ontario Lakes
Authors: Gemza A.F.
Published: March 2019

Two eutrophic lakes with seasonally anoxic hypolimnion were oxygenated utilizing hypolimnetic pure oxygen injection during 1995. Natural stratification was not disturbed. At Whittaker Lake, hypolimnetic oxygen levels were maintained between 4.0 and 5.0 ppm. Hypolimnetic total phosphorus concentrations did not increase beyond spring turnover levels, and lower concentrations of iron and manganese were measured, along with the elimination of all detectable hydrogen sulphide. The typical blue-green algal blooms fouling shorelines in the late summer and fall did not manifest themselves, but improvements in water clarity were not as dramatic as those observed at the second study site. During hypolimnetic oxygen injection in Heart Lake, where hypolimnetic oxygen levels were maintained at 2.0 ppm, the decline of zooplankton populations after a brief spring surge (clear water phase) was stopped and a shift to larger-bodied herbivorous cladocerans was observed — Bosminids were replaced by Ceriodaphnia species. Annual median water clarity improved from preaeration readings of 1.9 m to over 3.0 m. Small increases in hypolimnetic total phosphorus concentrations were observed in late summer under low level oxygenation, but were significantly less than pretreatment concentrations. The maintenance of an oxic hypolimnetic refugia not accessible to predator fish, but still able to oxidize sediments, was deemed important to the water clarity improvements. Historically low blue-green algal biovolumes and chlorophyll concentrations were recorded, and no beach closures due to algal blooms occurred. Hypolimnetic oxygenation is an effective tool which can improve lake water quality and ecosystem integrity.
Coping with Water Quality Problems due to Hypolimnetic Anoxia in Central Ontario Lakes
Authors: Nürnberg Gertrud
Published: March 2019

Many lakes experience oxygen depletion in their hypolimnia during summer or winter stratification. This study investigates the remedial actions that are available to combat the harmful effects of hypolimnetic anoxia in three types of Central Ontario lakes with different trophic states. In more eutrophic lakes, e.g., Lake Wilcox, southern Ontario, much phosphorus accumulates in the hypolimnion during anoxia and represents ca. 60% of the annual P budget. To diminish the detrimental effects of such a high internal phosphorus load, withdrawal of the hypolimnetic waters, together with damming of the surface water outflow, has been suggested. In oligo- to mesotrophic Chesley Lake, on the Niagara Escarpment, phosphorus accumulation in the hypolimnion is only slight and metals with a binding capacity for phosphorus are available. Here a hypolimnetic oxygenation has been suggested to alleviate the stress on fish and also to prevent further P release from the sediments. Lakes in the District of Muskoka are softwater lakes because of their location on the Canadian Shield. Although the geochemistry of the catchment typically renders these lakes nutrient poor and oligotrophic, long-term development on their shores has led to phosphorus accumulation in the sediments that is released under anoxic conditions in some lakes. To prevent the deterioration of the water quality in these lakes, water quality models to manage and control future development in its watersheds, as those of the district municipality, should include anoxia and internal P recycling in a quantitative manner.
Preliminary Results of Demonstration Capping Project in Hamilton Harbour
Authors: Zeman A.J. , Patterson T.S.
Published: March 2019

Placement of a pilot-scale sand cap occurred in Hamilton Harbour between July 31 and September 20, 1995. The harbour site is at a location where contamination of the bottom sediments is of concern. One ha of contaminated finegrained sediments was covered with 6,600 tonnes of clean sand to an average thickness of 30 cm. A very accurate positioning system was required and placement with adequate accuracy was possible up to wind speeds of about 30 km/h. Initial readings of settlement gauges taken in September 1995 show the ultimate settlement due to primary consolidation to range between 6 and 8 cm. Preliminary results indicate that the suspended material found in the water column during cap placement was almost entirely composed of fines associated with the cap sand. Vibracores showed a sharp interface between the sand cap and sediments with no signs of extensive mixing. Based on multibeam echo sounding results and other supporting data collected at the site, the sand cap was successfully placed in the designated area without any significant sediment disturbance. Some horizontal spreading of sand fines occurred beyond the site boundary.
Occurrence of Organotin Compounds in the Canadian Aquatic Environment Five Years after the Regulation of Antifouling Uses of Tributyltin
Authors: Chau Y.K. , Maguire R.J. , Brown M. , Yang F. , Batchelor S.P.
Published: March 2019

A survey was conducted of water and sediment from across Canada in 1993-94 to assess the effectiveness of the 1989 regulation of antifouling uses of tributyltin (TBT) under the Canadian Pest Control Products Act. The survey was also designed to assess concentrations of 13 other organotin species in water and sediment, and in sewage treatment plant influents, effluents and sludges. The main conclusion is that the 1989 regulation has only been partially effective. It has had some effect in the reduction of TBT concentrations in fresh water, but not in sea water. It has had less effect in the reduction of TBT concentrations in sediment, probably because of the longer persistence of TBT in sediment than in water. In many locations the TBT concentration was high enough to cause acute and chronic toxicity to aquatic and benthic organisms. In some areas there may be potential for recycling TBT from contaminated sediments back into the water column. In addition, it appears that large harbours that handle ships legally painted with TBT-containing antifouling paints continued to experience ecotoxicologically significant TBT contamination. Other organotin species found appear to pose no acute or chronic hazards to fresh water or marine organisms, but nothing is known of their hazards to benthic organisms. The presence of monooctyltin and dioctyltin in sediments and sewage treatment plant influents, effluents and sludges is reported for the first time, and tripropyltin is quantified in sediments for the first time.
Content of 3,4-Benzopyrene in Sediments of Lake Ladoga, Neva River and Eastern Gulf of Finland System
Authors: Frumin G.T. , Krylenkova N.L.
Published: March 2019

In 1993-94, sediment samples of the aquatic system comprising Lake Ladoga, the Neva River and the Eastern Gulf of Finland were collected to determine the content of 3,4-benzopyrene (3,4-PB) as an indicator of polycyclic aromatic hydrocarbons in the environment. Two methods were used: (1) microspectrofluorom-etry with quasi-linear spectra fluorescence and (2) high-performance liquid chromatography. Results show the heterogeneous distribution of 3,4-benzopyrene in the sediments. The highest concentrations (20 to 100 µg kg−1) were found in Lake Ladoga, near urban areas, and in the Neva River, near industrial compounds. High concentrations were also detected in the central part of Neva Bay and near a resort in the Gulf of Finland.
Feed Forward Backpropagation Neural Networks and their Use in Predicting the Acute Toxicity of Chemicals to the Fathead Minnow
Authors: Kaiser Klaus L.E. , Niculescu Stefan P. , Schüürmann Gerrit
Published: March 2019

Various aspects connected to the use of feed forward backpropagation neural networks to build multivariate QSARs based on large data sets containing considerable amounts of important information are investigated. Based on such a model and a 419 compound data set, the explicit equation of one of the resulting multivariate QSARs for the computation of toxicity to the fathead minnow is presented as function of measured Microtox, logarithms of molecular weight and octanol/water partition coefficient, and 48 other functional group and discrete descriptors.
Impacts of Municipal Wastewater Effluents on Canadian Waters: a Review
Authors: Chambers P.A. , Allard M. , Walker S.L. , Marsalek J. , Lawrence J. , Servos M. , Busnarda J. , Munger K.S. , Adare K. , Jefferson C. , Kent R.A. , Wong M.P.
Published: March 2019

Domestic sewage is a major threat to receiving waters throughout the world. In Canada, a high proportion of the population (81%) is served by municipal wastewater treatment facilities. Nevertheless, discharges from wastewater treatment plants, stormwater sewers and combined sewers have caused adverse impacts on some lakes, rivers and coastal waters. The most publicly recognized impacts are shellfish harvesting restrictions and beach closures resulting from microbial contamination. Habitat degradation and contamination also occur and these, in turn, have altered the abundance and diversity of aquatic organisms. Our findings on the effects of municipal wastewater discharge suggest that there is a need to review sewage treatment requirements in Canada. Further research is also required on the interactive and cumulative responses to habitat degradation and to long-term exposure to persistent and bioaccumula-tive pollutants. Finally, an integrated approach to wastewater management is needed that addresses loadings from treatment plants, stormwater sewers, combined sewer overflows and other wastewater sources.
Réduction de la demande en chlore et des précurseurs de sous-produits de désinfection par une ozonation suivie d'une biodégradation : effets de la reminéralisation
Authors: Zoungrana Charles J. , Desjardins Raymond , Prevost Michele
Published: March 2019

Des essais ont été faits afin de montrer les effets d'une reminéralisation sur les performances d'un traitement biologique. La demande en chlore ainsi que les potentiels de formation des trihalométhanes, des acides haloacétiques, des haloacétonitriles, des haloacétones et de la chloropicrine ont été suivis. Une augmentation de l'alcalinité des eaux permet un meilleur enlèvement des paramètres étudiés tant par l'ozonation que par la biodégradation. Par exemple, l'abattement des précurseurs de trihalométhanes, des haloacétonitriles et des acides acétiques est respectivement de 21, 50 et 28% dans les eaux non reminéralisées (alcalinité de 25 mg/L CaCO3). Dans les eaux reminéralisées à 250 mg/L CaCO3 ces abattements sont plus importants soit : 30, 68 et 50%. Un effet similaire est observé pour la biodégradation. Ainsi dans les eaux non reminéralisées les enlèvements sont de 54, 77 et 69%, alors qu’ils sont de 67, 86 et 80% dans les eaux reminéralisées.
Characterization of Treated Effluent from a Chemithermomechanical Pulping Process Using Macroporous Resins
Authors: Agbekodo K.M. , Huck P.M. , Andrews S.A. , Peldszus S.
Published: March 2019

This study developed a characterization of the organic matter remaining in a chemithermomechanical pulping (CTMP) effluent after biological treatment and evaluated the potential impact of this effluent when discharged into the receiving environment. The methodology employed involved fractionation with macroporous resins to allow for the isolation of hydrophobic and hydro-philic organic materials. The study also examined the treated effluent’s reactivity with chlorine, a typical drinking water disinfectant, in order to assess the formation potential of chlorinated by-products and the chlorine demand in a downstream drinking water treatment plant. Results showed that the dissolved organic carbon (DOC) in a treated effluent from a CTMP mill consisted of 87% hydrophobic material (primarily humic substances), 5% hydrophilic acids and 3 to 4% nitrogenous compounds. At least 95% of the DOC was isolated using three different macroporous resins. The chlorine demand of the biotreated CTMP effluent was two to three times higher than is typical for natural organic matter from surface water. This indicated that the organic material in the CTMP effluent was highly reactive with chlorine and will likely be reactive with other oxidants such as ozone, which is also applied in the drinking water industry. Moreover, the disinfection by-products chloroform and trichloroacetic acid were formed in high concentrations as a result of chlorination. The biotreated CTMP effluent had a high chemical oxygen demand (at least 1,100 mg/L) but a relatively low biochemical oxygen demand (less than 100 mg/L), which was to be expected after biological treatment. Hence, discharge of these effluents could release high concentrations of non- or slowly biodegradable organic matter into the downstream aquatic environment. Water pollution control policies should therefore consider the potential impact of treated effluents from CTMP mills with regard to their high DOC and the potential for chlorinated by-product formation upon drinking water disinfection.
Heavy Metals and PAHs in Stormwater Runoff from the Skyway Bridge, Burlington, Ontario
Authors: Marsalek J. , Brownlee B. , Mayer T. , Lawal S. , Larkin G.A.
Published: March 2019

Samples of stormwater runoff from the Skyway Bridge in Burlington, Ontario, were analyzed for five heavy metals (Zn, Pb, Ni, Cu and Cd) and 14 polycyclic aromatic hydrocarbons (PAHs) in dissolved and particulate-bound phases. Among the metals studied, the highest mean event-mean concentrations in whole-water samples were found for Zn, Cu and Pb (0.337, 0.136 and 0.072 mg L-1). These data compared well with those in the literature. Pb concentrations had to be compared to the most recent data reflecting the use of unleaded gasoline. Zn, Ni and Cu in the dissolved phase accounted for 35 to 45% of concentrations in whole-water samples. Mean PAH event-mean concentrations in whole-water samples ranged from 0.015 to 0.5 µg L-1 for individual compounds. Dissolved phase PAHs represented less than 11% of whole-water concentrations. Mean concentrations of Zn, Cu and Pb (997, 314 and 402 µg g-1) in runoff sediment were rather high and indicated that this sediment was “grossly polluted” according to the (Ontario) Ministry of Environment and Energy guidelines for sediment quality. Metal concentrations in the
An Integrated Acid Rain Assessment Model for Canada: from Source Emission to Ecological Impact
Authors: Lam D.C.L. , Puckett K.J. , Wong I. , Moran M.D. , Fenech G. , Jeffries D.S. , Olson M.P. , Whelpdale D.M. , McNicol D. , Mariam Y.K.G. , Minns C.K.
Published: March 2019

Integration of data and component models describing acidifying emissions, atmospheric transport, water and soil quality, fisheries, wildlife and socio-economics forms part of a decision-support system development for examining management options for acid rain issues in Canada post-year 2000. The emphasis is on scale consistency, optimization solutions, scenario testing and uncertainty propagation. The integrated model was evaluated with recent data and model consistency cross-checked with optimized and scenario testing results for Eastern Canada. Examples of predicted results on water quality and ecological impact were presented as part of an assessment for the evaluation of control options for acidifying emissions.
Acute Toxicity Testing with Juvenile White Sturgeon (Acipenser transmontanus)
Authors: Bennett W.R. , Farrell A.P.
Published: March 2019

The primary goal of this study was to investigate the possibility of using early life stages of white sturgeon (Acipenser transmontanus) (eggs, larvae and fry) as a species relevant to the Fraser River, B.C., for the acute and sublethal toxico-logical testing of forest industry effluents. Here we report the first successful acute toxicity tests for 8-day-old larvae and 42-day-old fry exposed to several chemicals known to be released into the Fraser River (i.e., 6 monochlorovanillin [6 MVAN], 4,5 dichloroguaiacol [4,5 DCG], 4,5 dichlorocatechol [4,5 DCAT], pentachlorophenol [PCP], and didecyldimethylammonium chloride [DDAC]). In most cases, white sturgeon fry were at the lower end of the range for acute toxicity values for chlorinated phenolic compounds, when compared with other juvenile fish species, and they were extremely sensitive to DDAC. The larval stage was usually more sensitive than the fry stage. Acute toxicity tests with fertilized eggs were unsuccessful. A postexposure growth study was inconclusive because neither control nor toxicant-exposed larvae and fry withstood the additional handling used for measuring body mass. At 62-days-old, fry were more tolerant of handling. This allowed measurement of their swimming performance. Although we have concerns about the reliability of using larvae for acute toxicity testing at this time, 60-day-old white sturgeon fry would appear to be both a sensitive and relevant species for assessing environmental impacts relevant to the Fraser River.
A Micro-Algal Solid-Phase Test To Assess the Toxic Potential of Freshwater Sediments
Authors: Blaise Christian , Menard Lucie
Published: March 2019

To assess the degree of toxicity of freshwater sediments which may arise from both readily available and ad(ab)sorbed contaminants, we have developed a novel "direct contact" solid-phase assay with the widely used Chlorophyte Selenastrum capricornutum. With this procedure, algal cells were exposed for 4 or 24 h to serial dilutions of test sediments. The capacity of exposed cell esteras-es to cleave the non-polar stain fluorescein diacetate and liberate fluorescein, a polar and fluorescent by-product, then becomes a criterion to determine the extent to which the algae have been intoxicated by the sediment. Individual cell fluorescence (from fluorescein) is rapidly and precisely quantified with the help of flow cytometry to determine a toxicity endpoint which relates to both esterase inhibition and cell membrane integrity. The algal solid-phase assay (ASPA) was appraised with certified reference material sediments prepared by the National Water Research Institute in Burlington as well as with some naturally contaminated sediments originating from various locations in the Québec portion of the Saint-Lawrence River. ASPA toxicity responses (IC50s) generated for sediments span over more than two orders of magnitude, indicating its apparent discriminatory power to demarcate their toxic potential on the basis of their contamination level. Correlation analysis, conducted with selected certified reference material sediments, suggests that ASPA responses may be partly linked to PAH and total PCB hold content. While further validation studies are planned for ASPA, it appears to promise as a useful phytotoxicity screening tool to assess the toxic potential of freshwater sediments.