bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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., &lt;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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.