bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preferential Leaching in Large Undisturbed Soil Blocks from Conventional Tillage and No-Till Fields in Southern Alberta
Authors: Miller J.J. , Lamond B.J. , Sweetland N.J. , Larney F.J. 
Published: March 2019

Abstract
There is a concern that adoption of conservation tillage practices such as no-till may increase preferential leaching of water and chemicals to the groundwater. Evidence from previous studies of long-term (since 1968) conventional tillage (CT) and no-till (NT) fields in southern Alberta suggests that tillage practice has the potential to influence preferential leaching. However, no studies have been done to test this hypothesis. Our objective was to utilize the two-region (mobile/immobile water) model of solute transport to compare preferential leaching in CT and NT fields of clay loam texture. Four large (46 × 46 × 51 cm) undisturbed blocks of soil were excavated from each tillage field (unreplicated) during the fallow phase of a wheat-fallow rotation. The soil blocks were transported to the laboratory, stored under drying conditions (32 months), and miscible displacement experiments conducted under saturated, steady-state conditions. Because of the long storage period, the focus of our study was on long-term (e.g., structure, earthworm burrows, old root channels) rather than short-term (e.g., tillage of surface soil) tillage effects on preferential leaching. Breakthrough curves (BTCs) for chloride were derived, and the modified convection-dispersion equation fitted to the experimental data using a two-region model (CXTFIT-Version 2.0 ) to allow estimation of the mobile water fraction (B) or extent of preferential leaching. Breakthrough curves for both tillage fields exhibited early initial breakthrough, a rapid rise in tracer concentration, a shift of the BTC peak to the left of one pore volume, and a slow decline (“tailing”) toward zero concentration for the descending limb of the curve. Reasonably good fits were obtained for fitting of the two-region model to the BTCs, as indicated by correlation coefficients ranging from 0.60 to 0.84. Mean values for the mobile water fraction were similar for the CT field (0.78) and NT field (0.80), suggesting no difference in preferential leaching of chloride. We hypothesize that the extent of preferential leaching in earthworm burrows (Aporrectodea caliginosa) in the NT field and leaching in old root channels in the CT field may have been similar. Further research on replicated plots is needed to examine short-term effects of tillage practice (e.g., tillage of surface soil) as well as the individual contribution of earthworm burrows and old root channels, to preferential leaching under CT and NT.
Contamination of Rural Drinking Water Wells by Fecal Origin Bacteria -- Survey Findings
Authors: Conboy M.J. , Goss M.J. 
Published: March 2019

Abstract
In 1997, over 300 rural drinking water wells throughout Southern Ontario and 148 wells in rural Zimbabwe were tested for bacteriological water quality. Total coliform, fecal coliform and fecal streptococci were enumerated in each sample with standard membrane filtration techniques. Clostridium perfringens was monitored by presence or absence. In Ontario, all of the wells were tested in the spring, when the fields were near saturation, and resampled in late summer. Just under 50% of the wells exceeded the Ontario drinking water objectives (DWO) in spring and summer. On both occasions, approximately 20% of the wells tested positive for Clostridium perfringens, which is an indicator for fecal contamination of animal origin. Zimbabwe wells were sampled during the dry season, June 1997. Ninety-five percent of the wells had bacteria in excess of Ontario DWO, and 59% of the wells tested positive for Clostridium perfringens. The wells in Zimbabwe provided a comparison in soil moisture and type, and there were also differences in well construction and management practices. This study shows that a significant percentage of the bacteria of fecal origin found in rural wells originated from animal manure. Some factors affecting well water quality are discussed.
Determination of Heavy Metals in Damascus Drinking Water Using Total Reflection X-Ray Fluorescence
Authors: Bakraji E.H. , Karajo J. 
Published: March 2019

Abstract
Total reflection X-ray fluorescence spectrometry and chemical preconcentration have been applied for multi-elemental analysis of Damascus drinking water. Water was taken directly from taps of several city sectors and analyzed for the following trace elements: Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Se and Pb. The detection limits were found to be in the range of 0.1 to 0.4 µg/L. The mean levels of trace elements in the Damascus drinking water were below the World Health Organization drinking water quality guidelines.
Monitoring Agricultural Drainage Ditches and the Receiving Water (Nicomekl River, Surrey, B.C.) for Toxicity to Ceriodaphnia dubia and Probable Cause Due to Organophosphate Contamination
Authors: McLeay M.J. , Hall K.J. 
Published: March 2019

Abstract
The use of organophosphate insecticides on commercial vegetable and blueberry farmlands bordering the Nicomekl River, Surrey, B.C., creates the potential for toxic effects on the biota within the drainage ditches and the river itself. To investigate the frequency and magnitude of the toxicity of drainage ditch water and the river water in the vicinity of ditch discharge points, together with the probable cause, water samples were collected from six drainage ditches, and four river locations, at 3-week intervals between June and November 1997. For each of the water samples collected, chronic (7 ± 1 day) survival and reproduction of the cladoceran test organism Ceriodaphnia dubia were compared to that of Nicomekl River headland waters beyond the influence of commercial growing operations. Portions of samples proving to be lethally toxic to the toxicity-test organism were analyzed for organophosphate insecticides (OPs) and subjected to treatment with piperonyl butoxide to ascertain if OPs were the likely contributing cause of the toxicity.
Throughout the 6-month monitoring period, a total of 50 ditch water samples and 35 Nicomekl river water samples were collected. None of the river water samples tested produced statistically significant mortality. Two (4%) of the ditch water samples were lethally toxic, with 6- and 7-day median lethal concentrations (LC50s) of 39.9 and 36.5%, respectively. Seven (14%) of the ditch water samples and three (9%) of the river water samples inhibited C. dubia reproduction. A biological toxicity identification evaluation using piperonyl butoxide determined that the toxicant(s) in each of the two ditch water samples which proved lethal to C. dubia were likely metabolically active OP insecti-cide(s). Later chemical analyses on stored portions of the samples revealed trace quantities of chlorpyrifos and/or diazinon. These and other non-measured OPs are believed to have been responsible for the observed lethality. The cause of the inhibited reproduction is for the most part unknown. Providing the 1997 growing season is a typical growing season in terms of OP insecticide use and rainfall, the C. dubia toxicity test results suggest that during the growing season the Nicomekl River and its drainage ditches may periodically be contaminated with OP insecticides at concentrations high enough to sublethally or lethally impact sensitive ditch and river invertebrate fish-food organisms.
Interference of Aluminum in Copper Biosorption by an Algal Biosorbent
Authors: Sung Lee Hak , Volesky Bohumil 
Published: March 2019

Abstract
Cu and Al sorption capacities of NaOH-treated Sargassum fluitans biomass were studied using equilibrium methodology. An evaluation of sorption performance and modeling in a two-metal system was carried out using a modified multicomponent Langmuir isotherm. The maximum Cu and Al uptakes calculated from the Langmuir isotherm were 1.54 mmol/g (9.8 weight percent) and 3.75 mmol/g (10.1 weight percent) at pH 4.5, respectively. However, these values were 1.35 mmol/g for Cu and 1.58 mmol/g for Al at pH 3.5. The modified Langmuir model gave the following affinity correlated coefficients: 0.20 for Cu and 6.82 for Al at pH 4.5, and 2.90 for Cu and 3.13 for Al at pH 3.5. The interference of Al in Cu biosorptive uptake was assessed by “cutting” the three-dimensional uptake isotherm surfaces at constant second-metal final concentrations. Equimolar final equilibrium concentrations of Cu and Al of 1 mM at pH 4.5 reduced Cu and Al uptakes by 83.4 and 5.5%, respectively. However, these reductions at pH 3.5 were 53.0 (Cu) and 29.1% (Al).
Extraction and Determination of RDX and HMX in Water
Authors: Vieira Eny M. , Onuska Francis I. 
Published: March 2019

Abstract
The analysis of energetic materials such as RDX and HMX in water at trace levels was accomplished by using micro-extraction by miscible solvents, such as acetonitrile, 2-propanol and acetone, and salting out the organic phase. This paper compares the results obtained with solid-phase extraction (SPE) to those obtained by demixing techniques for spiked Milli-Q water and an unfiltered lake water. A review of the data indicates that demixing with acetonitrile-sodium chloride and 2-propanol ammonium sulfate gives better extraction recoveries than solid-phase extraction. Salting-out extractions are performed in less time and with less solvent than by SPE techniques.
Spatial Characterization of the Occurrence of Road Salts and Their Environmental Concentrations as Chlorides in Canadian Surface Waters and Benthic Sediments
Authors: Mayer T. , Snodgrass W.J. , Morin D. 
Published: March 2019

Abstract
Increased concern over the contamination of surface waters by road salts and their adverse effects on the freshwater organisms led to the inclusion of “road salts” on the second Priority Substances List (PSL2) under the Canadian Environmental Protection Act The list identifies substances that must be assessed on a priority basis to characterize the nature and extent of the risk they pose to the environment or human health. This paper adds to the collection of several reports which constitute “supporting documentation” for the environmental risk assessment of the priority substance “road salts”. It reviews the physical-chemical properties of inorganic salts commonly used for road maintenance and their fate and transport in surface waters and sediments, together with the environmental concentrations of road salt constituents in the context of watershed geology and other environmental factors governing their concentrations. The paper also provides a spatial map of chloride concentrations as a basis for developing an understanding of a spatially based, ecological risk assessment for surface water systems and relates the spatial risk map to observed concentrations of chlorides. The data suggest that the surface waters most sensitive to road salts impacts are small ponds and streams draining large urbanized areas. Environment Canada is presently considering several alternatives for dealing with road salts.
Effects of Irradiation and Freezing on Toxicity of Sewage Sludge Elutriate Samples
Authors: Renoux Agnes Y. , Tyagi Rajeswar D. , Samson Réjean 
Published: March 2019

Abstract
The Microtox® assay (Vibrio fischeri) was used to determine if the handling of environmental or industrial samples affects their toxicity. Irradiation and 3-month freezing of sewage sludge elutriates decreased the toxicity of these samples as measured using the Microtox® test. The effect of storage at -20°C was also confirmed with the lettuce Lactuca sativa root elongation assay. Statistical independence (P &gt;0.05) between each handling and previous sludge treatment was observed, however, which indicated the possibility of comparing toxicity data obtained from different samples handled consistently.
Structure and Porosity of Alum Coagulation Flocs
Authors: Gorczyca B. , Ganczarczyk J. 
Published: March 2019

Abstract
It is generally assumed that flocs grow according to the following model: primary particles form compact flocculi which assemble themselves into microflocs. Microflocs bind together to form floc aggregates. The main difference between flocculi, microflocs and floc aggregates is their structure. Porosity can be used to indicate differences in this structure. The objective of this study was to establish whether alum flocs disperse into floc components that represent different structures, as indicated by different porosities. Alum coagulation floes were broken up with increasing amounts of mixing energy. The size and porosity of the studied particles were determined on microtome sections of the resin-stabilized samples. The results, as expected, indicated that the size and porosity of alum flocs decreased with the increase of applied mixed energy. Fractal analysis of pores revealed that alum floes contained at least three distinctive populations of pores: small, medium and large. The three pore populations indicate three levels of aggregation, i.e., flocculi, microflocs and floe aggregates. The results of this study confirm the previous theoretical and experimental investigations that argued for the multilevel floc structure.
Development of a Protocol for Sampling Faecal Coliform Bacteria Originating from Manure in the Vadose Zone
Authors: Unc Adrian , Goss Michael J. 
Published: March 2019

Abstract
Contamination of water resources with components of manure is a significant concern in Ontario. One aspect is the potential for bacterial transport through the vadose zone to groundwater following field application of manure. One obstacle to characterizing the movement of faecal bacteria in the vadose zone is the sampling of soil solution for bacteria. Porous-cup suction samplers are commonly used in estimating solute transport through this zone. However, there is little information on the calibration of such samplers for estimating numbers of bacteria in soil solution. This paper reports an attempt to make such a calibration. Tests were carried out under laboratory conditions which simulated the sampling of soil solution under field situation. As the suction applied was less than the air entry value for the ceramic porous cups used, the saturation status of the medium surrounding the cups was only important in terms of the number of colonies-forming units collected and not whether they were detected. The results indicated that although there were limitations in the use of the porous-cup suction samplers for bacterial sampling because of filtration effects, such samplers could be used for field collection of faecal bacteria from soil solution in situations with contrasting initial boundary conditions.
Performance of UASB Reactors at 6 to 32°C in Municipal Wastewater Treatment
Authors: Singh Kripa Shankar , Viraraghavan T. 
Published: March 2019

Abstract
The feasibility of using a high-rate upflow anaerobic sludge blanket (UASB) system for the treatment of low-strength municipal wastewater at 6 to 32°C was investigated for temperate climate applications. UASB reactors could be started up successfully in about 60 days at 20°C. Under stable conditions, the removal of COD, BOD and SS ranged from 38 to 90%, 47 to 91% and 50 to 92%, respectively, for a temperature range of 6 to 32°C. Sulfate reduction ranged from 10 to 90%, showing a decreasing trend with a decrease in temperature at each HRT. The average biogas production and methane content ranged from 167 to 199 mL CH4/g-CODremoved and 65 to 86%, respectively. The recovery of methane in the gas phase was very low compared with soluble COD removals, especially during operation at lower temperatures (6 to 15°C). Digital image analysis and scanning electron microscopy results indicated the aggregation of biomass in the form of flocs and small granules. The mean size of aggregated sludge particles increased from 0.2 to 3.0 mm, with a sludge volume index of 18 ± 2 mL/g during the operation.
Pollution métallique et organique des eaux et des sédiments d’un cours d’eau marocain par les rejets liquides urbains
Authors: Khamar Mohamed , Bouya Driss , Ronneau Claude 
Published: March 2019

Abstract
L’oued Sebou, l’une des ressources en eau les plus importantes du Maroc, reçoit quotidiennement un important volume d’eaux usées de la ville de Fès. La présente étude analyse l’impact de ces rejets sur la qualité de ce système aquatique. Les métaux lourds et éléments toxiques (Cr, Zn, Fe, Co, As, Ba, Sr, Ag, Hg, Sb et Rb) ont été déterminés, par activation neutronique, dans l’effluent urbain et dans les eaux et les sédiments du cours en amont et en aval de sa confluence avec les rejets. Les résultats ont montré qu’il y a une forte contamination du cours d’eau par ces métaux et que les facteurs de contamination les plus élevés ont été observés pour Cr et Zn, alors que Hg, Ag et As ne se retrouvent que dans les stations avales. De plus, dans les stations avales il y a une forte augmentation de la charge organique (DCO, DBO, matières organique volatiles), de la salinité et de la teneur en ammonium, en orthophosphates, en sulfate, en sodium et en calcium, et une chute drastique de la teneur en oxygène dissous. Outre la dégradation de la qualité des eaux, on a relevé une chute importante de l’indice biotique qui passe de 8 en amont à 2 en aval. Du fait du régime hydrologique du cours d’eau et des conditions climatiques de la région, les métaux lourds accumulés dans les sédiments peuvent être remobilisés et constituent un risque d’une contamination à grande échelle.
Effect of Additives on Biological Treatment of Landfill Leachate
Authors: Pouliot Julie-Marie , Yanful Ernest K. , Bassi Amarjeet S. 
Published: March 2019

Abstract
Aerobic batch bioreactors were used in this research to study the effects of different additives on the biological treatment of landfill leachate. Those additives were phosphoric acid, powdered activated carbon, polyethylenimine and BOD Balance™. Both synthetic and natural landfill leachates were investigated. The natural leachate was collected at a landfill site near London, Ontario. It was observed that the addition of phosphoric acid increased the COD utilization rate as well as decreased the effluent COD. The other additives did not affect the effluent COD but were found to have a small influence on the COD utilization rates, especially PEI and BOD Balance. A maximum average COD utilization rate of 90 mg L-1 h-1 was obtained with the following combination of additives: phosphoric acid and BOD Balance at 5 mg L-1.
The Urban Drainage Program of Canada’s Great Lakes 2000 Cleanup Fund
Authors: Kok Sandra , Shaw J. , Seto P. , Weatherbe D. 
Published: March 2019

Abstract
Since 1990, Canada’s Great Lakes 2000 Cleanup Fund, which is administered by Environment Canada, has been supporting the development and implementation of cleanup technologies to control municipal pollution sources, to clean up contaminated sediments, and to rehabilitate fish and wildlife habitats. These efforts are focused on Canada’s 16 Great Lakes Areas of Concern (AOCs) identified by the International Joint Commission for priority cleanup action and restoration of beneficial uses. Remedial Action Plans (RAPs) developed by federal/provincial teams and the public provide the strategy for restoring the beneficial uses of the AOCs.
Impairments in beneficial uses in the AOCs have been, in part, caused by discharges from combined sewer overflows (CSOs), Stormwater and sewage treatment plants (STPs). To assist municipalities in addressing the problems posed by urban drainage (CSOs and Stormwater), the Cleanup Fund’s Urban Drainage Program has been supporting the development and demonstration of innovative, cost-effective technologies and approaches. These projects include high-rate treatment of CSOs, real-time control of CSOs, performance assessment of Stormwater treatment technologies, pollution prevention and control plans, and development of Stormwater management planning tools for urban areas. These projects are carried out in collaboration with the Ontario Ministry of the Environment, municipalities, professional groups, universities and conservation authorities and other Environment Canada’s facilities (National Water Research Institute and Wastewater Technology Centre).
The Urban Drainage Program has been instrumental in advancing the state of the art in CSO and Stormwater management in Ontario. Projects supported under the program have quantified pollutant loadings from municipal wastewater sources in several Ontario Areas of Concern, provided hard data on the performance of best management practices for Stormwater treatment, identified and evaluated new cost-effective technologies for CSO reduction and Stormwater treatment, and developed strategies and decision-making tools for Stormwater management
The work done through the Urban Drainage Program is making it possible for Great Lakes communities to achieve important environmental objectives at significantly lower cost As a result, the communities should be able to achieve many of these objectives much earlier than they would have if their choices had been limited to more conventional and capital-intensive solutions. Although the program has focused on the needs of Areas of Concern in the Great Lakes basin, the lessons learned there can easily be applied to communities in other parts of the country and around the world.
Using Benthic Assessment Techniques To Determine Combined Sewer Overflow and Stormwater Impacts in the Aquatic Ecosystem
Authors: Rochfort Q. , Grapentine L. , Marsalek J. , Brownlee B. , Reynoldson T. , Thompson S. , Milani D. , Logan C. 
Published: March 2019

Abstract
Urban wet-weather sources of pollution such as Stormwater and combined sewer overflows (CSOs) can contribute significantly to the contamination of receiving waters, particularly in sediment depositional areas near outfalls. Analyses of sediment chemistry alone are not sufficient to fully assess the effects of these discharges. Toxicity testing and evaluations of benthic invertebrate communities, in conjunction with chemical analyses, provide a more complete characterization. This study assessed relationships among three separate aspects of the benthic environment:sediment chemistry (metals, PAHs and nutrients) and particle size, sediment toxicity (ten endpoints with four benthic taxa), and benthic invertebrate community structure. In this initial survey, ten sites in five different study areas, representing a range of receiving water environments exposed to Stormwater and CSO discharges, were sampled in October 1998. Results of analyses indicated that while contaminant (metals and PAHs) concentrations were relatively high in sediments, biological effects were not evident Toxicity of sediments was low and altered benthic communities were not detected. Neither toxicity endpoints nor benthic community descriptors were related to sediment contaminant levels. To improve the power of these assessments, future investigations of Stormwater and CSO discharge impacts should use “upstream/downstream” sampling designs and study sites with minimal variability of habitat conditions.