bluuebunny/crossref_metadata_2025_split huggingface dataset:
Groundwater Contamination by Chlorinated Hydrocarbon Impurities Present in Soil Fumigant Formulations
Authors: Zebarth B.J. , Szeto S.Y. , Hii B. , Liebscher H. , Grove G. 
Published: March 2019

Abstract
Groundwater contamination of the Abbotsford aquifer by 1,2-dichloropropane (1,2-DCP) was reported previously. The purpose of the present study is to quantify groundwater contamination by other chlorinated hydrocarbon compounds which are present in fumigant formulations containing 1,2-DCP. Widespread contamination of 1,2,2-trichloropropane (1,2,2-TCP) was measured consistent with a non-point source. 1,2,2-TCP concentration generally decreased with depth suggesting a surface source. Localized contamination by 1,2,3-trichloro-propane, 2,3-dichloropropene and 1,3-dichloropropane was detected. Detection of these compounds was associated with higher concentrations of 1,2-DCP suggesting contamination by these compounds may have been from the same fumigant sources. The lack of a decrease in the concentration of most of these compounds over time suggests that the measured contamination will persist for some time. The results highlight the potential for persistent trace impurities in chlorinated fumigant formulations to contaminate groundwater in vulnerable aquifers.
Toxicity of Tributyltin to Four Species of Freshwater Benthic Invertebrates Using Spiked Sediment Bioassays
Authors: Day Kristin E. , Maguire R. James , Milani Danielle , Batchelor Suzanne P. 
Published: March 2019

Abstract
The toxicity of tributyltin (TBT) in sediment in fresh water was determined using spiked sediment bioassays for four benthic invertebrates, (the oligochaete worm Tubifex tubifex, the chironomid Chironomus riparius, the amphipod Hyalella azteca, and the mayfly Hexagenia). Although there was some degradation of spiked TBT into dibutyltin (DBT) and monobutyltin (MBT) in the sediment-water mixtures during the equilibration phase before toxicity testing, the contribution of these degradation products to the observed toxicity was assumed to be minimal based on evidence that TBT is up to orders of magnitude more toxic to many aquatic organisms than its degradation products. The results of this work indicated that Hexagenia was the most sensitive benthic organism to TBT of the four organisms tested (by factors up to about 7), with an IC50 (growth) value for TBT of 0.6 µg Sn/g dry weight. This value is about six times greater than mean concentrations of TBT observed in sediment in fresh water in surveys conducted across Canada before and after the regulation of antifouling uses of TBT in 1989. However, maximum TBT concentrations in sediment before and after regulation exceeded the IC50 (growth) value for Hexagenia, and were close to the lower limits of toxicity ranges for H. azteca and T. tubifex (cocoons/adult and young/adult). Consequently, at the time of surveys before and after the TBT regulation there was potential for adverse effects of TBT in some sediments to some freshwater benthic species.
Review of Biodegradability Tests for the Purpose of Developing Regulations
Authors: Kaiser Klaus L.E. 
Published: March 2019

Abstract
The goal of this review is to propose acceptable testing method(s) for the measurement of the biodegradability of a chemical under both waste treatment and typical environmental conditions, particularly those relevant to Canada. A mul-titier biodegradability test system is recommended for the protection of the environment and human health. The tiers are comprised of International Organisation for Standardisation (ISO) standard tests for rapid biodegradability (headspace carbon dioxide evolution test, ISO #9439), for inherent biodegradability (activated sludge simulation test, ISO #11733) under oxidative conditions, and for biodegradability under anaerobic conditions (ultimate anaerobic biodegradability test, ISO #11734).
Temporal Variability of the Water Quality of Saline Lakes from the Soan-Sakesar Valley, Salt Range, Pakistan
Authors: Afzal Shahzad , Younas Mohammad , Ali Karamat 
Published: March 2019

Abstract
Saline lakes from the Soan-Sakesar valley are a breeding and feeding habitat for many shorebirds and waterfowl. In 1994, water samples were collected from lakes Uchhali, Khabbaki and Jahlar and analyzed for a variety of parameters such as Secchi disk transparency, chlorophyll a, total phosphorus, nitrate, alkalinity, pH, total dissolved substances, calcium, magnesium, sodium, potassium, chloride and sulfate. Chemical changes observed in 1994 were compared to those of 1986. The three lakes studied can be characterized as hypereutrophic. Their chemistry is controlled mainly by an evaporation-crystallization process and dissolved salts supplied by underlying sedimentary submerged springs. Uchhali Lake is saline, while Khabbaki and Jahlar lakes are brackish. The chemistry of the lakes is discussed in relation to their acidification from coal mines.
Environmental Situation in the Lower Dnipro River Basin
Authors: Vasenko O.G. 
Published: March 2019

Abstract
The paper summarizes Ukrainian findings and conclusions of the first Ukrainian-Canadian field study on the state of the environment in the Lower Dnipro River Basin. Three major issues were identified during the field study: accelerated eutrophication from municipal and agro-industrial discharges, industrial pollution, and radionucleide contamination of reservoir sediments. The Dnipropetrovsk-Zaporizhzhia-Kryviy Rih triangle has been recognized as an area which has been greatly affected by pollutants originating from many activities, including heavy industry, oil refining, metallurgy, petrochemistry, mining and power generation. The results of biological assays demonstrated that the Lower Dnipro River is endangered by toxic pollution originating from poorly treated or untreated effluent discharges. Of 58 industrial wastewater samples, taken at 31 outlets of the Dnripo and its tributaries, 69% contained various levels of toxic substances. Various degrees of toxicity were detected in 97% of 53 of the wastewater samples, taken at 37 sites. As a result, the majority of the tributaries sampled were of poor water quality and exceeded the statutory pollution standards. The diversity of phyto- and zooplankton was found to be severely reduced as was the native fish population in the Dnipro reservoirs. The maximum Cs-137 concentrations in bottom sediments of the Dnipro reservoirs varied from 31 to 520 Bq/kg, with the highest levels occurring in the reservoir closest to Chernobyl. The Ukranian government has identified the Lower Dnipro Basin as a top priority area for a strategic remedial action plan.
Chemical Contaminants in Fish and Sediment Core Samples from the Dnipro River, Ukraine, 1994
Authors: Lockhart W. L. , Muir C. G. , Wilkinson P. , Yarechewski A. , Billeck B.N. 
Published: March 2019

Abstract
Some aspects of the quality of fish and sediment samples with respect to contamination with organochlorine compounds, polycyclic aromatic hydrocarbons and several metals are addressed. Fish were obtained from three reservoirs: Kyiv, Kremenchuk and Kakhovka. Sediment cores were obtained from Kremenchuk, Zaporizhzhia and Kakhovka. Levels of contaminants in fish showed differences among species within a reservoir and among reservoirs within a species. The major organochlorine compounds found in the fish were DDT and PCBs with levels in the low ng/g range. Fish PCB levels generally tended to be higher in the Upper Kakhovka reservoir than in the other reservoirs and the congener profile suggested a local source of PCBs to that reservoir. Bream from the Kyiv reservoir had higher levels of mercury than bream from the other reservoirs even though they were of relatively small size. Lead-210 profiles in sediment cores suggested that all three cores sampled only recent time; two of the cores extended deeply enough to capture the large increase in cesium-137 from Chernobyl in 1986, and the third consisted only of material deposited after that event. Inputs of cesium-137 were high and there was no indication of decreases since 1986. Polycyclic aromatic hydrocarbons in sediments were also high, especially in the Zaporizhzhia reservoir where concentrations consistently exceeded Canadian sediment quality guidelines by sever-alfold. Concentrations were lower in the Kakhovka reservoir but still in excess of guidelines, and they were lower yet at the most upstream core from Kremenchuk reservoir. A similar pattern was evident with several metals in sediments. Concentrations in the core from Zaporizhzhia exceeded those from Kakhovka which in turn exceeded those from Kremenchuk. Concentrations in both Zaporizhzhia and Kakhovka generally exceeded Canadian sediment quality guidelines. The general picture that emerges is one of a system of widespread chemical contamination not only with Chernobyl byproducts but also with hydrocarbons, metals and organochlorines, with significant sources downstream from the Kremenchuk site.
Analysis of the British Columbia Water Quality Index for Watershed Managers: a Case Study of Two Small Watersheds
Authors: Zandbergen Paul A. , Hall Ken J. 
Published: March 2019

Abstract
The use of indices in ecosystem management is attractive because it allows for the representation of a complex set of information on ecosystem variables in a simple fashion. Recently the British Columbia Ministry of Environment, Lands and Parks developed the British Columbia Water Quality Index (BCWQI). As this index is currently being considered as the basis for other provincial indices and a national water quality index, the character of the BCWQI needs to be carefully considered. This study evaluates the performance of the BCWQI and assesses how useful and appropriate it is as a management tool at the watershed level. For this purpose the index is used to express the results of two sampling programs, one by the British Columbia Ministry of Environment, Lands and Parks, and the other by the Westwater Research Centre, of two relatively small watersheds in the Greater Vancouver area: the Brunette River watershed, heavily impacted by urbanization, and the Salmon River watershed on the urban-rural fringe. For both watersheds the intended use is the protection of aquatic life and only those water quality objectives are considered. The results indicate that the BCWQI is extremely sensitive to sampling design and highly dependent on the specific application of water quality objectives. A comparison is made with another type of index in widespread use in North America: the National Sanitation Foundation Water Quality Index (NSFWQI). This index appears promising for stream stewardship groups because of its simplicity and ease of use. For watershed managers, an alternative to the BCWQI is suggested, based on exceedance factors for individual objectives. This Simple Water Quality Index (SWQI) recognizes the importance of objectives that are specific to a particular water body, but overcomes some of the limitations of the BCWQI. A presentation format is suggested for objective exceedance factors, with a clear indication of exactly which objectives were included — without this, the final numerical index value is meaningless. This study suggests that the BCWQI in its current form has serious limitations for comparing water bodies and for establishing management priorities. If local watershed managers use the BCWQI in guiding efforts to protect aquatic resources, they should consider these limitations carefully.
Trace Metal Levels in Benthic Biota from Four Tributaries to the St. Lawrence River, Quebec
Authors: Renaud Claude B. , Wong Henry K.T. , Metcalfe-Smith Janice L. 
Published: March 2019

Abstract
Lamprey ammocoetes (Agnatha: Petromyzontidae) and freshwater mussels (Bivalvia: Unionidae), two groups of organisms that are closely associated with sediments, were collected from the Châteauguay, Bécancour, Sainte-Anne and Saint-Maurice rivers in July 1992 and analyzed for residues of 13 metals in their tissues. The hypothesis that lamprey larvae and mussels would bioaccumulate comparable levels of metals due to similarities in their ecology was rejected. Lampreys (Ichthyomyzon fossor and Lampetra appendix) from the Châteauguay River (the only site where both lampreys and mussels were collected) accumulated significantly lower concentrations of Ag, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Tl, V and Zn than mussels (Elliptio complanata), suggesting that lampreys may be capable of regulating these metals. Conversely, lampreys accumulated much higher concentrations of Hg than mussels (1748 to 6793 versus 579 to 982 ng/g dry weight, respectively), indicating that they may be suitable biomonitors for Hg. Organisms that are capable of regulating metals are not normally recommended for biomonitoring purposes. Nevertheless, significant differences among rivers were observed for many metals based on the lamprey data. As metals in the gut contents of three specimens of Sea lamprey (Petromyzon mar-inus) from the Saint-Maurice River accounted for a substantial portion of the whole body burden of metals, a gut content correction factor is recommended for these organisms. Further studies are required to properly evaluate lamprey ammocoetes as biomonitors for trace metals in freshwater systems.
Effect of Leachate Recirculation on Municipal Solid Waste Biodegradation
Authors: Warith Mostafa A. , Zekry Walied , Gawri Neeraj 
Published: March 2019

Abstract
Biological processes are known to reduce the organic fraction of municipal solid waste, but current landfilling practices have not been altered to reflect this knowledge. The advantages of enhancing degradation of solid waste include reduced period of leachate treatment, increased methane production, expedited landfill site reclamation through stabilized waste mining, and accelerated subsidence permitting recovery of valuable landfill air space. The techniques that can be used to enhance biological degradation include leachate recirculation, addition of nutrients, shredding, sludge and buffer solutions addition, lift design, temperature, and moisture content management. Manipulation of these variables promotes a more conducive environment for microbial activity. This paper presents the results of a leachate recirculation experiment into three pilots scale solid waste cells. A computer-operated pumping system controlled the rate of recirculated leachate into the solid waste cells. The leachate was recirculated over a period of 65 weeks, and effluent samples were obtained on a weekly basis and analyzed for pH, BOD, COD, TOC and heavy metal concentrations. The experimental results indicated that addition of supplemental materials to the leachate during recirculation has a positive effect on the rate of biological degradation of solid waste. The addition of primary sludge and supplemental nutrients resulted on a rapid increase in BOD and COD concentrations in the effluent samples. This rapid increase in BOD and COD concentrations suggests that following a lag phase prior to the methano-jenesis phase, a rapid decrease in the organic load in the leachate will be ichieved within a reasonable time frame. In addition, the results of this investigation indicates that the primary sludge is an excellent source of microbial inoculum. The addition of supplemental nutrients (nitrogen and phosphorus) with buffer also increases the concentration of the BOD and COD in the effluent samples, proving that a balance of pH and an increase in the available nutrients increases biological activities in the solid waste cells compared to the control cell.
Overview of Impacts of Recent Land and Channel Changes in Eastern Ontario
Authors: Watelet A. , Johnson P. G. 
Published: March 2019

Abstract
Recent land and channel changes on the Raisin River watershed in eastern Ontario altered the hydrological processes of the water cycle in a context of climate fluctuations. In particular, the development of agriculture faced two major obstacles in the area: a high water table and too long flood duration. Land transformations were intended to solve those problems and were relatively successful, though in accelerating the flow of land water toward the stream, the water balance was modified, which in turn changed the water quality dynamics. Surface hydrology and water quality of the Raisin River as they appear today are in part the result of past land transformations. Stream water quality restoration should therefore not be addressed alone but be integrated with restoration of hydrological processes at the scale of the watershed, a new necessity in the context of climate warming.
Developing Biological Endpoints for Defining Virtual Elimination: a Case Study for PCDDs and PCDFs
Authors: Servos M.R. , Parrott J.L. , Sherry J.P. , Brown S.B. 
Published: March 2019

Abstract
Defining virtual elimination has created considerable debate. A traditional approach has been to use chemically defined detection limits or levels of quantification that are determined using the best currently available methodologies. Ever increasing improvements in analytical techniques could lead to corresponding pressure to reduce the targets for virtual elimination. The current Toxic Substances Management Policy in Canada recognizes this and clearly states that it is not the intent of virtual elimination to have a moving target or to chase down the last molecule of the chemical of concern. Although it may be possible to reduce a chemical to less than some extremely sensitive detection limit, the chemical may or may not exert biological effects at that level. The chemically defined detection limits may be much lower than background levels in the environment, making it an unrealistic target. Conversely biological responses may result from trace levels of a compound that are not detectable in effluents or selected compartments of the environment (i.e., water) using current chemical techniques. Alternatively, an effect-based approach can establish biologically meaningful endpoints to defining virtual elimination. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) are used in this study as an example to evaluate the advantages and limitations of several possible approaches of using biological endpoints to determine the presence of these compounds in the environment and ultimately define virtual elimination. A review of the biological responses to PCDD/PCDFs is included to demonstrate the importance of selecting appropriate biological endpoints. Mixed function oxygenase (MFO) induction, although not recommended at this point, is used as an example of a possible sensitive endpoint that could potentially be used to detect exposure of biota to these chemicals. Three different approaches are explored: (1) measuring MFO induction in a sentinel species in the environment; (2) testing environmental extracts for MFO induction in cell lines; and (3) using biological endpoints (MFO induction) to define chemical targets for virtual elimination. While the use of biological end-points is the most desirable approach to defining virtual elimination, there are significant knowledge gaps which limit our selection and application of this approach.
Selenium Speciation of Surface Sediments from Saline Lakes of the Soan-Sakesar Valley Salt-Range, Pakistan
Authors: Afzal Shahzad , Younas Mohammad , Hussain Khadim 
Published: March 2019

Abstract
The chemical species of selenium from the surface sediments from three eutroph-ic lakes of the Soan-Sakesar Valley were examined. The major objectives of the study were to examine the oxidation states of selenium in the lake sediments. The following selenium concentrations were observed from lakes Uchhali, Khabbaki and Jahlar, respectively: total selenium: 4.03, 1.55 and 1.4 mg/kg; Se+VI: 0.86, 0.39 and 0.31 mg/kg; Se+IV: 0.95, 0.27 and 0.25 mg/kg; Se-II:1.15, 0.45 and 0.33; and Se0: 1.17, 0.48 and 0.53 mg/kg. Lake sediments have higher nitrogen (0.04—0.35% of dry weight) and phosphorus (0.04—0.29% of dry weight) levels due to agriculture drainage water and sewage waste from small villages. X-ray diffraction analysis has shown that albite, calcite, chlorite, illite and quartz minerals were present in the sediments of lakes Uchhali, Khabbaki and Jahlar. Kaolinite was present only in lakes Uchhali and Khabbaki and goethite only in Lake Uchhali. Linear relationships were observed between selenium fractions, and minerals present in these lakes point out the phenomena of adsorption on the surface of these minerals. The organic C contents of 2.2, 2.8 and 3.1% dry weight in lakes Uchhali, Khabbaki and Jahlar, respectively, show linear relationships with Se-II, Se0 and total selenium. It suggests that Se in the sediments is highly associated with the sediment organic fraction. The results indicate that nutrient loads and organic C are responsible for the high microbial activity, which reduces sele-nates to more insoluble Se species in the lake sediments.
Dissolved Organic Carbon Removal from a Prairie Water Supply Using Ozonation and Biological Activated Carbon
Authors: Sketchell Joanne , Peterson Hans G. , Christofi Nick 
Published: March 2019

Abstract
Large quantities of dissolved organic carbon in prairie surface water reservoirs make sustainable treatment quite challenging. Organic material is a precursor for the formation of disinfection by-products. Here, ozonation and biological activated carbon filtration were used as methods for removing dissolved organic carbon from the water of a small prairie reservoir used as a drinking water source. Biofiltration alone yielded significant reductions in dissolved organic carbon, colour, total trihalomethanes and chlorine demand. When ozonation preceded biofiltration, the increased proportion of biodegradable dissolved organic carbon allowed for significantly greater (p&lt;0.05
Removal of a Dye from an Aqueous Solution by the Fungus Aspergillus niger
Authors: Fu Yuzhu , Viraraghavan T. 
Published: March 2019

Abstract
Biosorption is becoming a promising alternative to replace or supplement the present dye removal processes from dye wastewater. In this study, removal of a dye, Basic Blue 9, from an aqueous solution by biosorption on the dead fungal biomass Aspergillus niger was studied. The effective pretreatment method for increasing the biosorption capacity of A. niger was investigated. Autoclaving was found to effectively enhance the biosorption capacity of A. niger to 18.54 mg/g compared with 1.17 mg/g of living cells for Basic Blue 9. Batch pH, kinetic and isotherm studies were conducted to evaluate the biosorption capacity of the pretreated (dead) biomass. The initial pH of the dye solution strongly affected the biosorption capacity and rate. The effective initial pH was between 4 and 6. The equilibrium time varied with the initial pH of the dye solution and was set at 30 h because no significant dye removals occurred after that time of contact. The Lagergren and Ho et al. models can be used to describe the kinetics of Basic Blue 9 biosorption on A. niger successfully for different initial pH values, except for pH 4. At initial pH 4, biosorption of Basic Blue 9 fitted the Langmuir equation well; at initial pH 10, the Langmuir and Freundlich isotherm models both fitted biosorption well. The results of this study indicated that fungal biomass of A. niger can be used for removing Basic Blue 9 from an aqueous solution.
Analyse régionale des étiages 7-jours de la province de Québec
Authors: Anctil François , Larouche William , Hoang Van Diem 
Published: March 2019

Abstract
Une analyse régionale des étiages 7-jours mène à un outil d'estimation fort utile à l’établissement de la qualité de l’eau suite à un rejet d’eaux usées, à la détermination d’un débit environnemental associé à un ouvrage de retenue ou encore à l’établissement d’un débit tiré garanti pour des fins industrielles, agricoles ou de consommation. À partir du débit observé de 119 stations de jaugeage sises au Québec, six régions homogènes ont été délimitées à l’aide d’un test de discordance et d’hétérogénéité. Diverses distributions régionales normalisées ont ensuite été ajustées à l’aide de la méthode des moments L. Les paramètres d’ajustement de ces distributions ont été estimés tant pour des étiages hivernaux qu’estivaux.