bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Microwave-assisted Extraction Method for the Determination of Synthetic Musks in Sewage Sludge
Authors: Svoboda M. Lewina , Yang Jian-Jun , Falletta Patricia , Lee Hing-Biu 
Published: May 2018

Abstract
An efficient microwave-assisted extraction (MAE) procedure has been optimized for the determination of polycyclic and nitro musks in sewage sludge. A centrifuged sludge cake sample (from 1 to 2.5 g ), mixed with 10 g of anhydrous sodium sulfate in a Teflon cell, was extracted with 30 mL of a 1:1 (v/v) mixture of acetone and hexane for 35 min, including a 15-min ramp with a 20-min hold at a controlled temperature of 110°C. After 30 min of cooling, the extract was evaporated and cleaned up on a silica gel column. A concentrated sample extract was then analyzed by gas chromatography/mass spectrometry (GC/MS) in the electron impact mode for the polycyclic musks and in negative ion chemical ionization mode for the nitro musks. This new method has been validated by comparing it to an established accelerated solvent extraction (ASE) method, with method detection limits ranging from 27 to 41 ng/g for the polycyclic musks, and approximately 4 ng/g for the nitro musks. Recoveries of most compounds in spiked samples ranged from 80 to 105%, although the MAE method produced lower recoveries for the nitro musks than the ASE method in archived sludge samples. The results generated by this MAE method were consistent with those prepared by previously reported techniques such as supercritical fluid extraction.
Pilot Treatment of OCC-based Paper Mill Wastewater Using Pulsed Electrocoagulation
Authors: Perng Yuan-Shing , Wang Eugene I-Chen , Yu Shih-Tsung , Chang An-Yi , Shih Chi-Yuan 
Published: May 2018

Abstract
There is an increasing trend towards the closure of white water recirculation loops in papermaking, often leading to need for system modification. A pilot-scale study was conducted using pulsed electrocoagulation technology to treat the wastewater of an old corrugated containerboard (OCC)-based paper mill, to evaluate its treatment performance. The operating variables were: a current density of 0 to 240 A/m2, a hydraulic retention time of 8 to 16 min and a coagulant (anionic polyacrylamide) dosage of 0 to 30 mg/L. The water quality indicators investigated were electrical conductivity, suspended solids (SS) and chemical oxygen demand (COD). The results obtained during the pilot-scale studies were favourable. Under the operating conditions without coagulant addition, the highest removals for conductivity, SS and COD were 47.7%, 99.3% and 75%, respectively. The use of coagulant remarkably enhanced the removal of both conductivity and COD. Using a coagulant dosage of 30 mg/L, the highest removal rates achieved for the three water quality indicators were 54.5%, 99.6% and 92.7%, respectively. These water quality levels are adequate to allow for the reuse of at least a part of the treated wastewater as makeup process water in papermaking.
A Shortened Adult Fathead Minnow Reproduction Test Developed for Investigation of Cause and Investigation of Solution Work Involving Pulp and Paper Mill Effluents
Authors: Kovacs Tibor , Martel Pierre , Ricci Maria 
Published: May 2018

Abstract
The regulatory Environmental Effects Monitoring (EEM) program in Canada has found that pulp and paper mill effluents reduce the gonad size of wild fish. In such cases, there is a need for Investigation of Cause (IOC) and Investigation of Solution (IOS) studies to find the cause(s) for these responses as well as cost-effective mitigation strategies. IOC and IOS work requires the availability of practical (in terms of time and effluent volume needs) and biologically meaningful tests for assessing fish reproduction in the laboratory. One available fish reproduction test uses adult fathead minnow (Pimephales promelas) and involves a two- to three-week pre-exposure period and a three-week exposure to a test substance. Work was undertaken to determine if both the pre-exposure and effluent-exposure phases could be reduced, leading to a shorter test with a lower effluent volume requirement. For this purpose, effluent samples were taken from two thermomechanical (newsprint) pulp mills and used in tests with ≤7 days of pre-exposure and 5 to 6 days of effluent exposure. Egg production was monitored in each test, and in tests with effluents from one mill, other endpoints - such as gonad somatic indices and whole-body sex steroid levels, as well as vitellogenin activity in males - were measured. The shortened fish reproduction test in this study provided results similar to tests of longer duration, specifically in terms of egg production, and was able to distinguish between pulp and paper mill effluents of different potencies. The test was also found to be directly applicable for toxicity identification evaluation work as it was clearly able to distinguish between the solids and soluble fractions of a biotreated newsprint mill effluent. As such, the test is a promising tool for EEM-related IOC and IOS work.
Optimization of Acetylcholinesterase and Metabolic Enzyme Activity in Multiple Fish Species
Authors: Georgiades Eugene T. , Holdway Douglas A. 
Published: May 2018

Abstract
An examination of acetylcholinesterase (AChE), citrate synthase (CS) and lactate dehydrogenase (LDH) activities in the brains of a range of fish species, occupying different trophic levels, is useful to investigate the full extent of the effects of sublethal or pulse exposures to pesticides. This investigation explores the optimization of microplate procedures for AChE, CS and LDH measurements in the brain tissue of species commonly used in laboratory investigations and those common to Canadian watersheds. A microplate assay was optimized for the measurement of AChE in the brain homogenates of seven fish species. The critical aspects of this assay requiring optimization were pH, substrate concentration and tissue dilution. Incubation with specific cholinesterase inhibitors indicated that enzymatic activity in the brain homogenates of each species was attributed to AChE only. Microplate assays were also optimized for the measurement of the metabolic enzymes, CS and LDH, in the brain homogenates of six fish species. For these assays, low interspecies variability was exhibited between optimized factors including pH, substrate, chromogen and cofactor concentrations. For each assay optimized, enzyme activities in the brain homogenates were stable for 2 to 3 hours post-thaw. Results from the present study will aid future ecotoxicological investigations of the potential impacts of AChE inhibition on neuronal glucose metabolism.
Persistence of Tributyltin-Induced Imposex in Dogwhelks (Nucella lapillus) and Intersex in Periwinkles (Littorina littorea) in Atlantic Canada
Authors: Coray Camille , Bard Shannon M. 
Published: May 2018

Abstract
Imposex in gastropods such as dogwhelks (Nucella lapillus) is a sexual abnormality that can cause sterility through the superimposition onto females of male sexual characteristics such as a penis homologue and/or vas deferens. Intersex similarly affects periwinkles (Littorina littorea) and is characterized by a phenotypic disturbance of sex determination between gonad and genital tract. A major culprit in causing imposex and intersex in aquatic gastropods is tributyltin (TBT), which is primarily used as a biocidal compound in antifouling paints, but is also present in sewage and wastewater due to industrial use. Since 1989, TBT has been banned in Canada for use on boats under 25 m in length, and in 2003, the ban was extended to include vessels of any length. However, observations of persistent imposex and intersex in marine snails from Halifax Harbour, Nova Scotia, Canada, suggest that current TBT controls are ineffective to eliminate this environmental problem in active ports. Dogwhelk imposex incidence ranged from 19% at the mouth of Halifax harbour to 100% midharbour, while no dogwhelks were found at the harbour head. Dogwhelks from uncontaminated reference sites outside the harbour yielded no cases of imposex. Imposex frequency and Relative Penis Size Index decreased at some of the sites between 1995 and 2006, but imposex frequency increased from 65 to 100% near a container pier, suggesting that TBT from antifouling paint on large (&gt;25 m) vessels like container ships may still be a strong environmental concern in Halifax Harbour. Periwinkles can tolerate higher TBT exposure and can be found where dogwhelks have been extirpated because of TBT contamination. Intersex incidence ranged from 0% outside the harbour to 100% at the head of the harbour at sites where no dogwhelks were found. Intersex indices corresponded with imposex indices where dogwhelks were found, and were relatively high (&gt;2.0) where dogwhelks were absent. Intersex rates and severity remained constant between 1996 and 2006. These data suggest that TBT-induced imposex may be at least partially responsible for the absence of dogwhelks in certain areas of Halifax Harbour. We also examined the impact of the loss of whelks, important predators for dominant mussels, on intertidal community structure and function. Due to the persistence of TBT in sediments and input of TBT into aquatic environments from sources other than vessel antifouling systems, current TBT controls may be of limited effectiveness in minimizing endocrine disruption and population decline in susceptible marine gastropods.
The Presence of Selected Pharmaceuticals and the Antimicrobial Triclosan in Drinking Water in Ontario, Canada
Authors: Servos Mark R. , Smith Martha , McInnis Rodney , Burnison B. Kent , Lee Bill-H. , Seto Peter , Backus Sean 
Published: May 2018

Abstract
The presence of pharmaceuticals and personal care products in the environment is a rapidly emerging international issue. A variety of drugs have been found in sewage effluents and surface waters in Europe, the United States, and Canada. This study examines the presence of selected pharmaceuticals (8 acidic drugs) and the antimicrobial substance, triclosan, in raw water and finished water of drinking water plants across southern Ontario. Twenty drinking water treatment plants that represented a variety of water sources and treatment process parameters were sampled. None of the raw or finished water samples taken from wells showed detectable levels of any of the acidic drugs or triclosan. River water samples downstream of sewage effluent outfalls showed the highest levels of contamination of the source water. Levels of naproxen and ibuprofen were elevated to levels as high as 176 and 150 ng/L, respectively, in raw water entering the treatment plants from a river source. Low levels of gemfibrozil (19.2 ng/L), diclofenac (15 ng/L), indomethacin (6 ng/L), and the antimicrobial triclosan (34 ng/L) could be also detected in raw water from river sources. Raw water taken from large lakes also had very low but detectable levels of several acidic drugs, suggesting that these chemicals are widespread in the environment. Although treatment systems are not designed to remove these specific types of substances, most of the acidic drugs were not detectable in finished waters. Naproxen and triclosan were detectable in finished water but were significantly reduced in concentration relative to the raw water. The concentration of ibuprofen was detectable in the finished water of almost all treatment plants that used surface water as a source. This work demonstrates the potential of Ontario source waters, particularly river water sources, to contain trace levels of selected pharmaceuticals and personal care products. There is a need to complete a more comprehensive assessment of these compounds in source waters and of the factors influencing their treatment and removal from finished drinking water.
An Evaluation of Rapid Bioassessment Protocols for Stream Benthic Invertebrates in Southern Ontario, Canada
Authors: Borisko Jeff P. , Kilgour Bruce W. , Stanfield Les W. , Jones F. Chris 
Published: May 2018

Abstract
In this study, we sampled stream benthos using rapid bioassessment methods (i.e., D-nets, coarse taxonomy) from sites in and around Toronto, Ontario that represented a range of stream characteristics (e.g., drainage areas). The protocols were developed by or adapted from: (1) Toronto and Region Conservation Authority, (2) Ontario Ministry of Natural Resources, (3) Ontario Benthos Biomonitoring Network/Ministry of the Environment, and (4) Canadian Aquatic Biomonitoring Network/Environment Canada. Summary indices (Hilsenhoff's modified Biotic Index [HBI]; percent of fauna as Ephemeroptera, Plecoptera, and Trichoptera [% EPT]; number of taxa [S]; and Shannon's Diversity Index [H']) calculated from the resulting data were used to evaluate differences between protocols in a series of analyses including analysis of variance and variance components analysis. The study found that sampling method was an unimportant source of variation in summary index values relative to other factors such as the stream or year sampled. The largest percent variance amongst stream or year factors (main and interactions) was at least three times greater than the corresponding method related percent variances. The results of this study suggest that these four bioassessment methods are interchangeable within the context of large geographic scales or for the detection of major impacts. In cases where impacts to the benthic community are subtle, protocols should include one or more of discrete habitat sampling, replication, and lower taxonomic resolution. The data and findings here may help agencies integrate different sampling protocols into their biomonitoring and assessment programs.
Evaluation of the Root Zone Water Quality Model (RZWQM) for Southern Ontario: Part II. Simulating Long-Term Effects of Nitrogen Management Practices on Crop Yield and Subsurface Drainage Water Quality
Authors: Ahmed Imran , Rudra Ramesh , McKague Kevin , Gharabaghi Bahram , Ogilvie John 
Published: May 2018

Abstract
Loss of nitrogen from the agricultural production system is of concern in Ontario. The challenge for researchers and farmers is to fulfill crop water requirements while limiting chemical movement with surface and subsurface runoff. The main objective of this study was to evaluate the long-term effects of current N management practices for corn production for two different soil types using the Root Zone Water Quality Model (RZWQM) for southern Ontario conditions. The model simulated the amount of subsurface tile drainage, residual soil nitrate-nitrogen (NO3-N), NO3-N in subsurface drainage water, and crop yield. The validated RZWQM for silt loam and sandy loam soils showed that the relative long-term effectiveness of the most economic rate of nitrogen (MERN) for corn production fluctuates significantly from year-to-year in response to weather patterns. In addition, soil type had a small but significant effect on the MERN. Side-dress application of N on sandy loam resulted in significant reduction in corn yield and NO3-N loss to shallow groundwater. Also, crop rotation from corn-soybean to corn-soybean-soybean resulted in a greater reduction of NO3-N loads in the tile outflow on silt loam soil than on sandy loam soil. Overall, the RZWQM simulated tile drain flow, NO3-N loss, and crop yield with reasonable accuracy. However, more field work is needed to assist with identifying suitable values for a number of coefficients used in the RZWQM's nutrient component for Ontario conditions.
Environmental and Economic Evaluation of Cow-Calf Wintering Site Runoff Control as a Beneficial Management Practice to Improve Surface Water Quality
Authors: Wuite James J. , Chanasyk David S. , Akbar Muhammad A. 
Published: May 2018

Abstract
A runoff diversion-collection system was evaluated as a beneficial management practice (BMP) for minimizing the impact of wintering site runoff on the water quality of an adjacent reach in the headwaters sub-basin of the Haynes Creek Watershed in central Alberta. Significant (α = 0.05) post-BMP mean annual load reductions of 13, 47, and 17% for dissolved, particulate, and total phosphorus, respectively, were realized. Mean annual loads of nitrate nitrogen and total Kjeldahl nitrogen were also reduced by 83 and 22%, respectively. The sum of total loads of Kjeldahl nitrogen and nitrate-plus-nitrite nitrogen, a surrogate measure of total nitrogen, also showed a reduction of 29%. However, mean annual load of total residue increased by 15%. Despite significance at the wintering site, these water quality changes were not statistically detected at the outlet of the subbasin. In spite of the measureable improvement in downstream water quality, adoption of the studied BMP represented a net economic cost to the producer under the current management conditions at the site. Furthermore, there appeared a need for concurrent implementation of BMPs in the headwaters sub-basin to be able to register any detectable changes in water quality at its outlet.
Trophic Status Evaluation for 154 Lakes in Quebec, Canada: Monitoring and Recommendations
Authors: Cloutier Rosa Galvez , Sanchez Michelle 
Published: May 2018

Abstract
Based on chlorophyll a, total phosphorus, transparency (Secchi disk), and total nitrogen, 154 lakes located in southern regions of the Quebec province were classified according to their trophic status. Various classification methods were presented and discussed. The evaluation of existing relationships among quality parameters were established, and suggestions for priority actions and restoration initiatives were given. The ‘Reseau de surveillance de lacs’ of the Ministère de développement durable, environnement et parcs is considered as a very successful program that should be increasingly supported by the government. The program meets sustainable development principles in watershed management. The results showed that although the majority of lakes surveyed were within optimal conditions (oligotrophic status), 22 lakes required closer surveillance and more effective nutrient control measures.
Modelling Nitrification of a Lagoon Effluent in Moving-Bed Biofilm Reactors
Authors: Houweling Dwight , Monette Frédéric , Millette Louise , Comeau Yves 
Published: May 2018

Abstract
A pilot study was performed at the Sainte-Julie wastewater treatment plant to evaluate the potential of using the Moving-Bed biofilm reactor (MBBR) process for removing BOD5 (5-day biochemical oxygen demand) and ammonia nitrogen in a two-stage process at the exit of the first lagoon. Nitrification was observed in the first reactor at rates similar to those reported in the literature for a similar biomass carrier when bulk liquid dissolved oxygen (DO) concentrations were 6 g of O2 per m3. Nitrification rates were significantly reduced when DO was reduced to 3 g of O2 per m3. DO concentrations were maintained at 6 g of O2 per m3 in the second reactor, and nitrification rates comparable to those reported in the literature were observed for a temperature range of 3 to 16°C. An empirical DO-limited model was validated for the first reactor while in the second reactor nitrification was found to be either DO limited or total-ammonia-nitrogen limited, depending on nitrification rates in the upstream reactor. The DO-limited model predicts that the MBBR process is more sensitive to organic load than it is to temperature. A commercially available numerical model was calibrated to the results of the pilot study. Model results indicate that detachment and attachment rates play an important role in determining nitrification rates in the biofilm. Similar nitrification rates in an MBBR system installed upstream and downstream from an aerated lagoon in winter conditions were predicted using the empirical DO-limited model.
Air-Water Oxygen Transfer with Multiple Plunging Jets
Authors: Deswal Surinder , Verma Dharam Veer Singh 
Published: May 2018

Abstract
Despite numerous works reporting on oxygen transfer by plunging jets, few studies have been carried out on multiple plunging jets. In this paper, the volumetric oxygen-transfer coefficient and oxygen-transfer efficiency of multiple plunging jets in a pool of water for different configurations in terms of varying numbers of jets and jet diameters were studied experimentally. This research suggests that the volumetric oxygen-transfer coefficient and oxygen-transfer efficiency of the multiple plunging jets for air/water systems were significantly higher than those of a single plunging jet for same flow area and other similar conditions. A relationship between the volumetric oxygen-transfer coefficient and jet parameters is also proposed. The suggested relationship predicted the volumetric oxygen-transfer coefficient for single and multiple plunging jet(s) within a scatter of ±15%.
Modeling and Assessment of the Produced Water Discharges from Offshore Petroleum Platforms
Authors: Chen Zhi , Zhao Lin , Lee Kenneth , Hannath Charles 
Published: May 2018

Abstract
There has been a growing interest in assessing the risks to the marine environment from produced water discharges. This study describes the development of a numerical approach, POM-RW, based on an integration of the Princeton Ocean Model (POM) and a Random Walk (RW) simulation of pollutant transport. Specifically, the POM is employed to simulate local ocean currents. It provides three-dimensional hydrodynamic input to a Random Walk model focused on the dispersion of toxic components within the produced water stream on a regional spatial scale. Model development and field validation of the predicted current field and pollutant concentrations were conducted in conjunction with a water quality and ecological monitoring program for an offshore facility located on the Grand Banks of Canada. Results indicate that the POM-RW approach is useful to address environmental risks associated with the produced water discharges.