bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uranium Tailings Acidification and Subsurface Contaminant Migration in a Sand Aquifer
Authors: Dubrovsky N.M. , Morin K.A. , Cherry J.A. , Smyth D.J.A. 
Published: March 2019

Abstract
Investigations of the geochemistry of inactive pyritic uranium tailings in the Elliot Lake Mining district of Ontario have focused on the Nordic tailings management area, where two impoundments are located in natural bedrock basins. The tailings are 8-12 m thick and overlie a localized deposit of glaciofluvial sands. Analyses of the solid, liquid, and gas phases in the vadose zone of the tailings show that gas-phase oxygen levels drop rapidly within 0.7 to 1.5 m of the surface, indicating rapid oxygen consumption during pyrite oxidation. Oxidation during the past 15 to 20 years has caused a marked depletion of near-surface pyrite.
The oxidation of pyrite in the vadose zone imparts to infiltrating precipitation high concentrations of Fe, SO42-, various heavy metals, and a pH generally between 1.5 and 4. The acidic infiltration moves downward at a rate of 0.2 to 2.0 m/yr, displacing high-pH groundwater that originated as process water discharged from the mill. It now occupies the entire tailings thickness over a small area of the tailings.
At one location a well-defined plume of high-Fe2+ tailings-derived groundwater has developed in the sand aquifer adjacent to the tailings. The plume consists of three zones: an inner core characterized by Fe &gt; 5000 mg/L, pH &lt; 4.8, and elevated concentrations of several heavy metals and radionuclides; an outer zone with Fe &lt; 2500 mg/L, pH &gt; 5.5, and relatively low concentrations of heavy metals and radionuclides; and a transition zone separating the two. Although the average linear groundwater velocity is about 440 m/yr near the dam, reactions such as mineral dissolution, precipitation and coprecipitation retard the migration of the front of the inner core, producing an observed frontal migration rate of approximately 1 m/yr.
Groundwater from the outer zone of the plume flows laterally towards a small stream, where a portion of it is now discharging into the stream bed. The discharge results in the precipitation of amorphous ferric hydroxide on the stream bed. Most of the H+ produced by Fe precipitation is buffered, and only a moderate decrease in stream pH is observed. Inner zone conditions will not reach the stream unless input of low-pH groundwater from the tailings continues for several hundred years.
Although the rate of pyrite oxidation in the Nordic Main tailings has been decreasing, there is sufficient pyrite in the tailings to generate high-Fe groundwater for several decades or more. Calculated groundwater migration rates indicate that in the next few decades acidic, low-pH groundwater will occupy the entire tailings thickness over most of the tailings area, causing an increase in the total flux of contaminated groundwater into the underlying aquifer. The outer zone of the plume has already arrived at a small stream, and acidification of the surface waters may increase if the Fe concentration in the groundwater seepage increases.
The Impact of Mining and Smelting on Trace Metal Distribution in Lake Sediments Around Rouyn-Noranda, Quebec
Authors: Arafat Nabil M. 
Published: March 2019

Abstract
Metal leachate from sediment cores obtained from seven lakes around Noranda Copper smelter in Quebec exhibited maximum levels of 7297 μg/g, 14469 μg/g and 246750 μg/g of Cu, Zn and Fe respectively in lakes near the emissions source, and lower levels in lakes away from the smelter. The sediment enrichment factor (SEF) among these lakes varied with respect to distance from the smelter. Lakes within 10 km from the smelter had an (SEF) of 166, 118 and 130 for Cu, Zn and Pb respectively; lakes at 25 km or more had SEF's ranging from 1 to 5.5, with the exception being lake Duparquet, where Mo value of 25 was obtained. These enrichment factors are among the highest recorded in the world.
Seasonal Variations of 2,4-D in Buckhorn Lake
Authors: Nagy E. , Painter D.S. 
Published: March 2019

Abstract
A five month survey of 2,4-D in Buckhorn Lake water and sediment, combined with streamflow data, produced estimates of the chemical in the lake. The peak concentrations in the water alone were significantly higher than the documented uses would permit. Two distinct concentration peaks were shown by the chemical: one during the June milfoil control season, and one in late August, indicating a release of 2,4-D from the collapsed and decaying milfoil beds. The observed rates of disappearance of the chemical agreed with reported values, showing a limited persistence in the lake. The presence of 2,4-D in the spring sediments was attributed to land runoff.
Toxicity of Para-Chloro Substituted Benzene Derivatives in the Microtox™ Test
Authors: Kaiser Klaus L.E. , Ribo Juan M. , Zaruk Brian M. 
Published: March 2019

Abstract
This paper gives the results of part of a systematic investigation into contaminant toxicity to Photobacterium phosphoreum in the Microtox™ test. Reported are the toxicity values for 39 para-chloro substituted benzene derivatives of the general formula l-Cl-C6h4-4-X=CH2CH(NH2)COOH, F, SO2NH2, OCH2COOH, CH2COOH, CONHNH2, NHCOCH3, CONH2, CH=CHCOOH, SeOOH, CH2NH2, CH2CH2NH2, NO2, H, CF3, CHO, CH2OH, OH, CH3, CCl3, COCH3, COOH, NH2, SO2C6H5, Cl, CH2COCH3, COCl, CN, OCH3, NCO, NHCH3, I, COC6H5, CH2Cl, SH, CH2SH, NCS, CH2CN and SO2C6H4Cl. Except for the last compound, whose solubility is below the required concentration, the toxicities increase in the presented order with a total range of more than three orders of magnitude.
The data are discussed in terms of quantitative structure-toxicity correlations with compound-specific structural parameters. In combination with a previously developed submodel on chlorinated benzenes, phenols, nitrobenzenes and anilines, the observed relationships allow the prediction of the toxicity of some 780 possible chloro derivatives of the general formula C6H5-nClnX, where n=&lt;5 and X is a functional group as listed above.
Non-Intrusive Estimation of Active Volume in Anaerobic Reactors
Authors: Hall Eric R. 
Published: March 2019

Abstract
A stimulus-response and flow modelling technique was developed for the examination of internal mixing patterns in high rate anaerobic reactors. This method allowed the effects of biomass accumulation to be monitored in a non-intrusive manner which avoided interruption of the reactor operation. The analysis was applied to three pilot scale systems which utilized different reactor designs for anaerobic wastewater treatment.
The results of multiple tracer studies demonstrated that high rate anaerobic processes most closely resemble well mixed reactors. However, significant deviations from ideal behaviour were noted. A flow model incorporating bypass and dead volume was found to adequately describe the measured tracer results. Estimates of reactor actively mixed working volumes obtained by the modelling approach were highly correlated to void volumes measured by an intrusive technique. The stimulus-response methodology is suitable for routine application in full scale facilities where an assessment of biomass accumulation effects is required.
Influence of Chloride on Kinetics of the Adsorption of Mercury (II) by Poorly Crystalline Al, Fe, Mn and Si Oxides
Authors: Wang J.S. , Huang P.M. , Hammer U.T. , Liaw W.K. 
Published: March 2019

Abstract
The kinetics of Hg adsorption by poorly crystalline Al, Fe, Mn, and Si oxides in 0, 10-3, and 10-2 M NaCl solutions were investigated. The influence of Cl- on the Hg adsorption very significantly varied with the kinds of the hydrous oxides studied. The rates of Hg adsorption by the hydrous oxides of Al, Fe, and Si steadily decreased with increasing Cl- concentration in solution. The rate constants of the fast adsorption process of Hg by the oxides of Fe, Al, and Si decreased by 21.3, 6.5 and 6.4 times, respectively, in 10-2 M NaCl solution. In the same NaCl concentration, little decrease in the rate constant of the Hg adsorption by Mn oxide was observed. The effect of ionic strength and Na+ on the Hg adsorption by the oxides was not evident. The results indicate that the nature and properties of hydrous oxides which are commonly present in freshwater sediments merit close attention in the extent of the influence of a road deicing salt, NaCl, on the dynamics of Hg in aquatic environments.
Treatment of Landfill Leachate; Management Options
Authors: Maris P.J. , Harrington D.W. , Mosey F.E. 
Published: March 2019

Abstract
Three management options for the treatment of leachate from landfilled domestic solid waste have been evaluated. Research results show that leachate can be treated effectively in aerobic systems, with high organic carbon and ammoniacal nitrogen removals of &gt;90% and &gt;85% respectively. Optimum SRT of about 10 days is required. Anaerobic treatment (UASB) with HRT's of between 1.0 and 4.0 days results in COD destruction of about 85% with high methane production (400-600 mg/g COD removed) and provides an intermediate effluent suitable for polishing to a high standard.
Recirculation of leachate through the landfill by itself cannot provide a complete treatment, although significant reductions in volume and strength of leachate can be obtained.
Influent Constraints on Treatment and Biological Nitrification of Municipal Landfill Leachate
Authors: Jasper S.E. , Atwater J.W. , Mavinic D.S. 
Published: March 2019

Abstract
A laboratory-scale treatment process was set up to treat Port Mann Landfill leachate, a high ammonia, low degradable carbon leachate with occasional high metals. A single sludge, nitrification/denitrification system was run for 25 weeks, with methanol added as a carbon source to improve denitrification. The objective of the treatment process was to remove biodegradable carbon and ammonia (feed levels of 25 to 250 mg/L).
Carbon removal, including methanol, was adequate at SRT's of 10 days or greater. An SRT of 5 days produced inadequate treatment. Of the metals of concern, all except nickel were concentrated in the biomass. Ammonia removal was inconsistent. Good nitrification occurred at the start of the study but no denitrification occurred until operating conditions were optimized. Both processes deteriorated as the study progressed. The study clearly demonstrated that changing influent characteristics constrained the overall treatment of the leachate.
Aerial Photography for the Detection of Leachate Migration from Landfills
Authors: Birkbeck A.E. , Tomlins G.F. 
Published: March 2019

Abstract
Aerial photography of the perimeters of two landfilled areas in British Columbia was acquired in colour and infrared emulsions. The photography was examined for evidence of leakage, or flooding of the leachate collection ditches surrounding the landfill and vegetation stress caused by the landfilling.
At. one site the photography was acquired using a miniature experimental remotely piloted aircraft. This aircraft carries two gimbal-mounted 35 mm cameras which allow simultaneous vertical photography using two different film emulsions, different lenses, and/or filter combinations. At the second landfill site, oblique aerial photography was acquired from a Cessna 172 aircraft.
Preliminary interpretation of the photography was followed by visits to locations where possible problems associated with leachate containment were apparent. The results indicated several locations where leachate was not fully contained by the ditch network and some areas of vegetation stress.
Further studies at the second site confirmed that improved containment was effective in preventing further environmental damage.
Factors Affecting the Recovery of Heavy Minerals from Oilsand Tailings by Flotation
Authors: Ityokumbul M.J. , Kosaric N. , Bulani W. , Cairns W.L. 
Published: March 2019

Abstract
The recovery of heavy minerals from oilsand tailings by flotation has been studied. The results obtained indicate that the optimum pH is in the range of 8.3–11.7. Pine oil was used as a frother and the optimum concentration was found to be 0.15% (v/v) while frothing was depressed at its critical micelle concentration (CMC) in the extraction cell water (0.30% v/v). The use of starch to depress iron recovery also resulted in the depression of the heavy minerals. It is therefore suggested that iron removal be accomplished in the subsequent upgrading operations. The residual bitumen in these tailings appears to be associated with the gangue component of the solids. With a feed containing 10–12% TiO2 and 4–5% zircon, a heavy minerals concentrate containing 28–30% TiO2 and 10–12% zircon is obtainable at 85–95% recovery of these minerals if frothers are used. The flotation process under study has been shown to offer significant advantages over other heavy minerals recovery processes that have been developed and patented to date.
Considerations for Network Design for Water Quality and Quantity Surveys in Canada
Authors: Ongley Edwin D. 
Published: March 2019

Abstract
A network of water quantity and/or quality stations is a composite of many different management information requirements. Conventionally, the objective of such stations has been to describe and quantify one or more of discharge, sediment flux, or water chemistry. This perspective is site-specific and descriptive. While quantity and quality surveying are usually separated, comprehensive water resource management is a composite activity involving the interrelationships amongst discharge, chemistry, biology, land use, etc.. The static and site-specific objectives of contemporary network stations fulfil limited management information requirements. Future network design should include a specific focus on functional behaviour of the watershed and its aquatic ecosystem. Behavioural data serve two contemporary objectives. One pertains to aquatic ecosystem management and/or protection. The second pertains to assessment of anthropogenic interventions within watersheds. The network requirements to meet these new information demands are examined in the context of conceptual, methodological and normative developments within the field of aquatic science and environmental assessment.
Studies of the Production of Volatile Fatty Acids in the Anaerobic Digestion of Municipal Sludge
Authors: Jones P.H. , Szekely J. 
Published: March 2019

Abstract
Volatile fatty acids (VFA’s) produced during anaerobic digestion of sludge have higher commercial value than methane produced subsequently. Therefore it was decided to determine conditions necessary to maximise production of VFA’s. Five anaerobic digesters were operated in parallel in the laboratory to investigate the effect of pH on the formation of VFA’s. Concentrations of individual fatty acids were measured. Both VFA production as well as gas production was favoured by pH approaching neutrality.
Évaluation de la toxicité subléthale des effluents industriels vis-à-vis du poisson en mesurant l’ATP du muscle squelettique
Authors: Blaise C. , Trottier B. , van Coillie R. , Couture P. 
Published: March 2019

Résumé
Une procédure relativement simple a été développée pour déterminer le stress énergétique chez la truite arc-en-ciel par des concentrations sublétales d’effluents industriels. Les principales conditions expérimentales sont les suivantes: exposition de 96 heures aux effluents, prélèvement de tissu musculaire, détermination de l’ATP extrait à l’aide du dimethylsulfoxide. Les poissons ont été exposés à sept effluents pour lesquels on a précisé des valeurs CL50 et des CMS (concentrations minimales induisant le stress). Une forte relation log-log linéaire (r=0,948) a été observée entre les données de létalité et de sublétalité. Ceci rend possible la prédiction des seuils de stress pour les effluents à partir des données CL50. D’autres constatations (expérience avec poissons stressés, détermination d’une valeur CMS pour le cuivre, comparaisons avec des données de létalité et de sublétalité dans la littérature) ont confirmé la représentativité environnementale du test CMS. Ainsi, l’utilisation d’un indicateur biochimique tel que l’ATP semble approprié pour la mise en évidence du potentiel écotoxique sublétal des effluents.
Microbiological Detoxificaion of Resin Acids
Authors: Servizi James A. , Martens Dennis W. , Gordon Robert W. , Kutney James P. , Singh Mahatam , Dimitriadis Eugene , Hewitt Gary M. , Salisbury Philip J. , Choi Lewis S. L. 
Published: March 2019

Abstract
The fungus, Mortierella isabellina, was used to define the biochemical transformations required to detoxify three resin acids and three chlorinated resin acids commonly found in pulp mill effluents. Detoxification was based on bioassays using Daphnia pulex and, whenever feasible, sockeye fry (Oncorhynchus nerka). Hydroxylation at C(2a) generally was the initial step in detoxification and usually resulted in at least a ten-fold reduction in acute toxicity. Additional hydroxylation further reduced acute toxicity. Ring cleavage was not required to detoxify the resin acids or their chlorinated derivatives. Furthermore, substantial reductions in acute toxicities of chlorinated compounds were achieved without chlorine removal.
Evaluation of Reverse Osmosis for the Treatment of Oil Sands Produced Water
Authors: Mehrotra Anil K. , Banerjee Abhijit 
Published: March 2019

Abstract
The “produced” water obtained from Shell’s Peace River In Situ Project was found to contain moderately high levels of dissolved sodium and calcium salts along with about 350 mg/L, total carbon. Two commercially a vailable spiral1y wound non-cellulosic reverse osmosis cartridges tested in this study were able to bring down the total dissolved solids content of the waste to less than 100 mg/L.
The effects of several process variables such as the feed rate, pressure and pH we re investigated. Prior to the actual wastewater treatment runs, a series of control experiments with distilled water, and NaCl and CaCl2 solutons were performed. These control experiments helped in standardizing the membranes and in evaluating import ant membrane parameters. The membranes were tested with the wastewater sample at pressures from 1.7 to 6.2 MPa, flow rates from 1 to 10 L/min, and at pH levels of 4, 6 and 7. Overall, the UOP membrane was found to be more effective in treating the wastewater than the ABCOR membrane.
Organic Extractables in Municipal Wastewater Vancouver, British Columbia
Authors: Rogers Ian H. , Birtwell Ian K. , Kruzynski George M. 
Published: March 2019

Abstract
Composite five to seven-day sample s of chlorinated and unchlorinated primary-treated municipal wastewater were collected at the Iona Island treatment plant during a 62-day exposure of juvenile chinook salmon (Oncorhynchus tshawytscha). No differences between chlorinated and unchlorinated samp les were detectable and only 9 chlorinated extractables we re identified.
Mass spectrometric analysis of sewage and sludge extracts identified 100 base/neutral components and 60 acidic substances. Some major constituent s we re quantified. Fatty acids, petroleum hydrocarbons, aromatic acids and chemical disinfectants we re predominant.
Toxic compounds present included chlorophenols, polynuclear aromatic hydrocarbons (PAH’s) and nonylphenols plus nonylphenolethoxylates. Tetrachlorophenol (TCP) and pentachlorophenol (PCP) reached maximum levels of 7.8 and 13.2 μg · L−l respectively. The PAH’s we re heavily concentrated in sludge samples. Nonylphenol was present in wastewater and sludge but the corresponding ethoxylates occurred only in wastewater. PCB’s were detectable only in sludge. Some novel identifications included two substituted monochiorophenol disinfectants and two generic drugs.
Heavy Metal and Organochlorine Contaminants in the Five Major Ontario Rivers of the Hudson Bay Lowland
Authors: McCrea Robert C. , Fischer John D. 
Published: March 2019

Abstract
Water, bottom sediment and two species of fish collected upstream of the mouths of the Moose, Albany, Attawapiskat, Winisk and Severn Rivers were analyzed for heavy metals and a wide range of organic contaminants. Iron and aluminum were present in raw water samples with mean concentrations ranging from 260 to 860 ug/L and 60 to 470 ug/L respectively. Polycnlorinated biphenyls (PCBs), α-BHC, γ-BHC, cis-chlordane, trans-chloroane, p,p’-DDE, dieldrin and HCB were also found in water at levels comparable to an industrialized region of Ontario. Organochlorine pesticides, cnlorobenzenes, polyaromatic hydrocarbons and phthalates were not detected in bottom sediments, however, trace amounts of PCBs were found in Moose and Severn River sediments. Trace concentrations of a few organochlorine contaminants were detected in both fish species. The solubi1ization, absorption and bioaccumulation of many of the contaminants were thought to have been affected by the presence of naturally occurring organic acids.
Organochlorine Contaminants in Headwater Peatlands, and Selected Estuary Sites of the Moose River
Authors: McCrea Robert C. , Wickware Greg M. 
Published: March 2019

Abstract
Peatland waters of the Moose River basin, as well as surficial sediments and vascular plants of the estuary were sampled in 1982. Elevated levels of PCBs were found at all five peatland sites; concentrations ranged from 28 to 65 ng/L. Of the seventeen organochlorine pesticides investigated, the hexachlorocyclohexane isomers (a-and y-BHC) were the most prominent with total BHC concentrations ranging from 1.5 to 13.7 ng/L. The presence of these contaminants in ombrotrophic bogs indicated that there was atmospheric deposition of organochlorine contaminants in the basin. Analyses of surficial sediments, collected from tidal flats and coastal marshes, showed that PCBs and organochlorine pesticides were not present. Samples of Triglochin maritima L. seed heads and Typha latifolia L. roots were also free of PCBs.
Inhibition of Nitrite Oxidation During Nitrification: Some Observations
Authors: Suthersan S. , Ganczarczyk J.J. 
Published: March 2019

Abstract
A series of laboratory experiments were performed under controlled pH conditions and at room temperature to quantitatively study the inhibitory effects on Nitrobacter during nitrification. The results indicated that, in addition to the free ammonia (FA) concentration, the pH itself played an additive role in the inhibition of Nitrobacter. Reactors which were maintained at the same FA concentrations but at different pH levels exhibited different inhibition characteristics. It was also found that the acclimatization of Nitrobacter for an extended period of time may increase its FA tolerance limit from 0.1–1.0 mg/L cited in literature to 2.5 mg/L. Laboratory units containing less biomass (about 1000 mg/L) were more sensitive to FA inhibition than those with a higher concentration (1500 mg/L). A new concept of “recovery time” was introduced in this study to describe the microbial behaviour under inhibited conditions. The recovery time of Nitrobacter was found to depend on FA concentration, pH, time of exposure and biomass concentration.
Priority Site Selection for Degraded Areas Based on Microbial and Toxicant Screening Tests
Authors: Dutka B.J. , Walsh K. , Kwan K.K. , El-Shaarawi A. , Liu D.L. , Thompson K. 
Published: March 2019

Abstract
The results of a study to evaluate the suitability of a variety of microbiological, biochemical and bioassay tests to become part of a battery of test procedures to identify degraded or degrading water bodies, are presented. Data for this study were obtained from 51 inshore sampling sites along the north shore of Lake Ontario from Kingston to Niagara River. Data examination indicated that microbial population, biochemical or bioassay tests performed independently do not provide realistic estimates of priority concern areas and that the battery approach is required. From this study the sampling sites of highest concern were: Humber River STP out fall, mouth of Mimico Creek, mouth of Credit River and Bay of Quinte near the Belleville STP outfall.