bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of Metal Toxicity Using Natural Phytoplankton as Test Organisms in the Great Lakes
Authors: Munawari Mohiddin , Legner Milos
Published: March 2019

This paper presents an overview of techniques utilizing natural phytoplankton for the detection of metal-Induced stress in the Great Lakes. Both field and laboratory procedures are designed to evaluate either structural changes or functional response of test organisms. This up-to-date compendium provides a choice of techniques, which permits a holistic assessment of the stress caused by toxic metals. Recently introduced techniques, such as normalized size spectra analysis, flow cytometry, and the evaluation of a continuous-flow system response to metal toxicity, are discussed in more detail to explore their future potential. Owing to their key position in the food web, high turnover rates, abundance, and sensitivity to environmental perturbation, phytoplankton serve as reliable early warning indicators of ecosystem deterioration and its restoration.
Water at the Outlet of the St. Lawrence River Part I - Sampling and Major Cations
Authors: Barbeau C. , Sérodes J.-B. , Paquet M.
Published: March 2019

The St. Lawrence River exports important loads of contaminants to the estuary, but good estimates of annual loadings are presently not available. During two years (1989–91), discrete and composite samples were taken on a daily basis at the water intake of the drinking water treatment plant of Lévis in front of Québec City. Our data indicate that discrete samples are representative of the bulk of the water and that magnesium or calcium measurements provide valuable information on the species transported to the estuary in the dissolved phase. Any decrease in magnesium concentrations at Lévis is the result of relative flow increases from the tributaries of the river. Using high flow episodes in tributaries and daily magnesium measurements at Lévis, the time of transport of the dissolved phase from many sources along the river has been evaluated. At high flow, the time of transport from the Carillon Dam (on the Ottawa River) to Lévis is 11 days, while it is 8 days from Beauharnois. With these data, a predictive model using magnesium (or calcium) as the chemical parameter characterizing the dissolved phase of the St. Lawrence River at the mouth of the estuary was developed. Loadings to the estuary of any dissolved contaminant can now be estimated by combining daily calculated flow values with daily measured water composition at Levis.
St. Clair River Head and Mouth Water Quality Monitoring, 1987–89
Authors: Chan C. H.
Published: March 2019

Water and suspended sediments samples were collected at the head and mouth of the St. Clair River from 1987 to 1989 for organic contaminant analysis. Higher concentrations and higher frequencies of detection of many organic contaminants. in particular penta- and hexachlorobenzenes, hexachlorobutadiene and octachlorostyrene were measured at the river mouth. Year to year comparisons showed substantial reduction in concentrations of hexachlorobutadiene and octachlorostyrene in suspended sediments.
Trends in Nutrients, Major Ions, Physical Water Quality Parameters and Trace Metals in the Niagara River from 1975 to 1989
Authors: Kuntz Kenneth W. , Tsanis I.K.
Published: March 2019

This paper presents the seasonal and annual variations of the physical parameters, nutrients, major ions and trace metals in the Niagara River for a period of 15 years (1975–89). The discharge during this period was found to be increasing until 1986, after which a large decrease was observed. As a consequence, the specific conductance decreased until 1985 due to the higher dilution effect as well as the lower concentrations of chloride and sodium. High concentrations of total phosphorus during the winter months corresponded with high turbidity and high suspended solids concentrations. In addition, a steady decrease in total phosphorus concentrations was observed until 1984, but since then has levelled off. Nitrate nitrogen concentrations were found to be steadily increasing from 1975 to 1987, and then a large decrease was observed. Both chloride and sodium concentrations decreased substantially from 1975 to 1989, as a result of upstream industrial input decreases, but concentrations since then have levelled off. Iron and aluminum concentrations and loads have shown steady increases since 1975, probably due to increased sediment loads in the October to January period, while lead, nickel, zinc and chromium concentrations and loads are declining.
The Acid-Phase Anaerobic Digestion of Primary Sludge and Its Role in the Biological Phosphorus Removal Process
Authors: Elefsiniotis P. , Oldham W.K.
Published: March 2019

The effects of certain operational and environmental parameters on the acid-phase anaerobic digestion of primary sludge have been investigated using a series of bench-scale, continuous-flow experiments. Short-chain volatile fatty acids (VFA), the main products of the process, are preferred substrates for the bacteria involved in the biological removal of phosphorus. Results show that the net volatile fatty acid generation improves with an increase in hydraulic retention time (up to 12 hours) as well as in solids retention time. Although acid production is not affected by a decrease in pH from 5.1 to 4.5, the production is significantly lower (25 to 30%) at pH of about 6.0. The use of different feed sources influences to some extent the amount of product formation. Moreover, lipid and carbohydrate degradation patterns are dependent on reactor configuration, whereas protein utilization appears to be independent of the reactor regime. The amount of VFA produced, in most cases, is high enough to support biological phosphorus removal processes.
Anaerobic Treatment of Cheese Dairy Wastewater Using the SNC Bioreactor
Authors: Mulligan Catherine N. , Safi Bechara F. , Meunier Jacques , Chebib Jean
Published: March 2019

The SNC multiplate reactor (1,200 L) has been developed and tested to determine chemical oxygen demand (COD) removal, nutrient requirement, and gas production from the anaerobic treatment of effluents generated at the Agropur (Notre Dame-du-Bon-Conseil, Quebec) and Nutrinor cheese dairies (Chambord, Quebec). At the Agropur plant, wastewater (3,000 mg/L COD) was treated the best at a retention time of 12 h. Using this retention time, effluents containing whey with organic loads of 10.2 to 41.6 kg COD/m3/day could be treated at a 84% COD removal rate. When the reactor was subjected to shock by increasing the organic load suddenly from 8.9 to 31 kg COD/m3/day, the total COD removal decreased to 72% and then returned to 86% after 7 days. Hydrology tests indicated that the reactor functions as a series of completely mixed stirred tanks. At Nutrinor, using a 12-h retention time and diluted whey permeate (20,000 mg/L COD), total COD removal was 86% and gas production was 12.0 m3/m3/day for a loading of 36.5 kg COD/m3/day. Nutrient supplementation was not required. For experiments performed with different proportions of wastewater (2,000 mg/L COD) to whey permeate (70,000 mg/L COD) results of 89% total and 93% soluble COD removal with a gas production of 11 m3/m3/day for a loading of 25 kg COD/m3/day were obtained. Retention times were varied from 18 to 60 h to correspond to initial CODs of 20,000 to 70,000 mg/L. In conclusion, this reactor functions in a superior manner to other published anaerobic treatment systems.
Biofiltration Pilot Test at the Daishowa Pulp and Paper Mill Using the Biocarbone Process
Authors: Séguin François A. , Tremblay Bruno , Zaloum Ronald , Lavallée Pierre , Lapointe Serge
Published: March 2019

As a result of increasing industrial activity and stricter application of environmental standards, pressure is being brought on Industries to improve the quality of their effluents. To achieve these goals, cost-efficient and high-performance wastewater treatment processes are needed. Recently, tests were completed on the treatment of ground wood, TMP and de-inking process effluents at the Daishowa, Quebec, pulp and paper mill. The biological treatment used was a fixed-film process known as the “Biocarbone” process. These tests demonstrated conclusively the high effectiveness of the Biocarbone process at COD loads of up to 10 kg/m3.day. This represents a major savings of space when compared to conventional waste activated sludge processes with COD loads of 2-3 kg/m3.day. The object of the test was to verify BOD5 levels, TSS removal and toxicity levels with respect to existing environmental standards. At all times and for all conditions tested, the Biocarbone process met the accepted standards of 5 kg/t of BOD5, 8 kg/t of TSS, and total removal of toxicity on a monthly basis
Mécanismes de toxicité du dinitro-o-crésol dans les chloroplastes
Authors: Pascal Jean , Popovic Radovan
Published: March 2019

L’inhibition du transport d’électron photosynthétique des plantes d’orge (Hordeum vulgarae) par un herbicide phénolique (DNOC) a été étudié. Ces expériences ont été réalisées afin de pouvoir mieux connaître les sites d’inhibition ainsi que les principaux modes d’action de cet herbicide.

Les résultats ont démontré que le DNOC agit en inhibant au contact, du côté donneur et accepteur du PSII simultanément. L’inhibition du côté oxydant, via le complexe de dégagement d’oxygène, est partielle (70%) et semble affecter les PSII situés dans les empilements granaires. Du côté réducteur, l’action du DNOC est plus complexes. Ainsi, à faibles concentration (<10 µM), le DNOC agit comme un accepteur d’électron au niveau de QA. A de plus fortes concentrations, cet herbicide inhibe la chaîne de transport d’électron au niveau du même site ainsi que du côté accepteur du PSII.
Indice de fluorescence algale et variations de pH appliqués à l’étude des effets du pétrole dispersé sur le phytoplancton marin
Authors: Roy Suzanne , Simon Robert , Pelletier Émilien
Published: March 2019

Le suivi environnemental d’une communauté phytoplanctonique lors de l’imposition d’un stress toxique requiert l’utilisation d’indices écotoxicologiques à la fois rapides et sensibles. Dans ce contexte, une série d’expériences en laboratoire et en mésocosmes de 3,5 m3 a été réalisée afin d’établir l’intérêt de deux indices: (!) la fluorescence algale, avant et après empoisonnement avec le DCMU, et (ii) les variations de pH comme indicateurs de toxicité en présence de pétrole dispersé. Ces deux indices se sont révélés capables de suivre l’évolution de l’activité algale sous des conditions expérimentales reflétant l’hiver et le printemps dans les eaux du fleuve Saint-Laurent et des concentrations de pétrole variables. L’indice de fluorescence utilisé, reflet du potentiel photosynthétique, augmente en présence d’une forte croissance algale mais diminue à de très faibles valeurs dans les réservoirs fortement intoxiqués. Le pH subit aussi une augmentation lorsque la croissance phytoplanctonique, ou plus exactement le bilan net photosynthèse-respiration est positif, alors que la toxicité des produits pétroliers est reflétée par une diminution ou une stabilisation du pH. Les effets d’une contamination pétrolière ainsi que les possibilités d’application de ces méthodes sur le terrain et en laboratoire sont discutés.
Toxic Effects of Copper on Selenastrum capricornutum Measured by a Plow Cytometry-Based Method
Authors: Arsenault Guy , Cvetkovic Alexandre D. , Popovic Radovan
Published: March 2019

Adaptation of algae Selenastrum capricornutum to different copper concentrations (50,150,300 and 450 ppb) was investigated. A flow cytometry technique was used to evaluate esterase activity (staining probe: CFDA). Algal physiological stress was estimated by comparing the esterase activity profile of intoxicated samples to that of a control sample. Our results show that at high concentration (450 ppb), copper strongly reduces esterase activity, whereas it increases that activity at lower concentrations (<300 ppb). After 27 hours of incubation, the esterase activity level resumed to the normal profile for each copper concentrations. The esterase activity profile thus shows adaption processes of algae Selenastrum capricornutum to copper intoxication.
Inhibition Mode of S-State Transitions by Sulphate in Oxygen Evolution by Photosystem II Alpha
Authors: Beauregard M. , Meunier P.C. , Popovic R.
Published: March 2019

Thylakoids Incubated with sulphate show an inhibition of oxygen evolution. However, analysis of oxygen production patterns induced by flashes reveals that sulphate treatment does not modify the “miss probability” in the advancement of the S-state cycle. This indicates that the PSII inhibited by sulphate are completely blocked in oxygen evolution, while another part of PSII is left intact. Therefore, the measured oxygen yields originate only from unaffected PSII. Our interpretation is supported by fluorescence measurements, which show a decrease in PSIIalpha fluorescence, while the apparent rate of Qa reduction in active PSIIα is not changed after sulphate treatment. Thus, sulphate induces a complete shut-off of S-state transitions in a part of the PSIIα population, leaving the other part intact; PSIIβ were not affected. This implies that the antagonist actions of chloride and sulphate do not proceed through a fast equilibrium.
Septic Tank Effluent Treatment Using Laboratory-Scale Peat Filters
Authors: Coleman R.N. , Gaudet I.D.
Published: March 2019

Filter columns were designed, constructed from sand, peat and coarse gravel, and their effectiveness assessed in the treatment of septic tank effluent. An initial loading rate of 4 cm/d was applied to the filter columns in either a downward or upward flow at a temperature of 10°C or 20°C. The loading rate was later increased to 8 cm/d. Filter-column plugging occurred in the downward flow treatment but not in the upward flow treatment. Fecal Coliform removal was usually greater than 95%, BOD removal was greater than 75%, and various removal levels were exhibited for other components. Microbial colonization of peat and gravel was effective as revealed by scanning electron microscopy.
Lixiviation biologique des métaux lourds et stabilisation des boues municipales
Authors: Benmoussa H. , Tyagi R.D. , Campbell P.G.C. , Blais J.F.
Published: March 2019

La présence de teneurs élevées en métaux lourds retrouvées dans les boues de stations d’épuration est un facteur important limitant l’épandage agricole de cette biomasse potentiellement fertilisante. Au cours des dernières années, quelques procédés microbiologiques d’extraction des métaux lourds ont été examinés. La mise au point d’un procédé qui permettrait conjointement l’enlèvement des métaux lourds et la stabilisation des boues est évidemment souhaitable. L’approche poursuivie dans cette étude était de vérifier si le procédé microbien de lixiviation des métaux lourds développé dans notre laboratoire pourrait éventuellement remplacer les procédés conventionnels de stabilisation des boues municipales. Les résultats obtenus en cultures discontinues avec des boues secondaires prélevées d’un réacteur biologique séquentiel (RBS) montrent que la forte chute de pH (< 2.5), laquelle est liée directement à la quantité de soufre ajouté à la boue, entraîne une solubilisation importante des métaux (Al: 20–31%, Cd: 81-99%, Cr: 17–43%, Cu: 85–97%, Fe: 13–49%, Mn: 90–100%, Ni: 66–84%, Pb: 20–44%, Zn: 91–97%). De plus, ce procédé permet une réduction appréciable des matières en suspension volatiles (33%), alors que les propriétés fertilisantes des boues traitées sont conservées (N: 90%, P: 100%, K: 100%).
Value of Supplemental Air in Improving RBC Performance
Authors: Surampalli Rao Y. , Tekippe Rudy J. , Baumann E. Robert
Published: March 2019

Rotating biological contactors (RBCs) have been used extensively, but the process units had structural and operational problems. The main problems were related to low dissolved oxygen levels, resulting in thicker biomass growth in the initial stages. This paper discusses the observed value of supplemental aeration in improving RBC performance and in ensuring longer media and shaft life because of reduced mass of biofilm growth. Three full-scale upper-midwest RBC plants, having supplemental aeration in the first two stages, were studied to determine the value of supplemental air in improving RBC performance and in controlling Beggiatoa growth. These plants were operated over a fairly wide range of organic loading. The study results indicated that it was possible to achieve higher BOD5 removal rates when RBCs were provided with supplemental air. In addition, higher dissolved oxygen levels, resulting from the supplemental air, enhanced BOD5 removal and ammonia nitrification significantly. The resulting thinner biofilms also ensured longer life for the media and shaft. Supplemental aeration can be provided with nominal capital investment.
Sediment Records of Man’s Activities in the Kootenay Lake Drainage Basin
Authors: Macdonald R.W. , Carmack E.C. , Pharo C.H.
Published: March 2019

Four cores from Kootenay Lake have been dated using 2l0Pb. These cores have also been analyzed for total Pb concentration specifically to compare the sediment record with the known history of lead-zinc mining around the lake. Two sorts of impact on the lake are recorded in the sediments. First, there is obvious contamination by Pb in which concentrations within cores parallel the regional “boom-and-bust” mining history. Second, the sedimentation rate appears to have been affected by damming of the inflowing rivers and probably also by logging and the associated road construction in the watersheds. Spatial variability within the lake sediments is evident: sedimentation rate is highest towards the north and south ends of the lake where river inflow is greatest; contamination by Pb is highest in the middle of the lake close to the major mining activities.
Phosphorus Dynamics in Riverine Lakes
Authors: Kenney B.C.
Published: March 2019

Simple models based on conservation of mass capture the essential dynamics of total phosphorus in lakes. The concentration of total phosphorus in shallow riverine lakes on the Prairies was simulated as a forced response to the inflow concentration. The lake dynamics were characterized by three independent time scales based on water inflow, water outflow and sedimentation. Both inflow and outflow time scales were necessary to model lakes with non-stationary hydrographe and varying lake levels. Flood periods had a pronounced effect on lake phosphorus because high concentrations in the inflow occurred when the lake was dynamically able to respond. In the Fishing Lakes, the 1974 flood appears to have established the lake conditions for the next decade. Most other large peaks in the concentration of total phosphorus in the inflow occurred when the outflow time scale was large and the lakes were dynamically unable to respond. Net sedimentation of total phosphorus appeared to be zero in these lakes over the two decades for which data were available. Verification of the lack of net sedimentation in shallow lakes means that no model calibration is needed to apply these simple models to other shallow lakes. Presently, however, even the simplest models are restricted by the lack of appropriate data required for verification.
Studies of Bottom Ekman Layer Processes and Mid-Lake Upwelling in the Laurentian Great Lakes
Authors: Saylor James H.
Published: March 2019

Profiles of horizontal current velocity have been measured over long time intervals across bottom Ekman layers in Lake Michigan. Measurements at offshore locations in water depths greater than 100 m have disclosed current speeds exceeding 25 cm s"1 at 1 m above the lake floor during winter storms when the lake water is unstratified. Counterclockwise veering of the current velocity vector occurs as the bottom is approached, with the veering being most rapid close to the bottom. Measurements of currents during winter and spring have shown prevailing cyclonic circulation at all water depths. This is true of the other deep Great Lakes as well. Mass conservation calculations with the current meter data yield upwelling velocities on the order of 1 m day'1 in the center of the lake during winter. Water temperature data have been obtained from thermistor strings attached to meteorological buoys moored in the center of the lake by the National Data Buoy Center, Bay St. Louis, Mississippi. Simulations of the temperature data with four different one-dimensional mixed layer models were all premature in timing the onset of stratification. Additional simulations of the temperature data were made with a constant upwelling velocity imposed through late spring. Results of the new simulations were significantly improved over those neglecting upwelling. These results emphasize the importance of Ekman pumping in retarding the start of stratification in large lake basins.
Some Aspects of the Thermal Regime of Large Lakes: Lake Ladoga and Lake Onega
Authors: Naumenko M.A.
Published: March 2019

Physical limnological experiments relating to water temperature and currents were conducted in lakes Ladoga and Onega over the period 1985–90. Details of the lake thermal cycle, thermal bar formation, circulation, and heat flux characteristics in the region of the thermal front in these two large lake systems are described. In addition, consequences relating to chemical and biological distributions in the area of thermal front development and progression are discussed.
Anaerobic Detoxification of a Chemi-Thermomechanical Pulp Effluent by Two Acclimating Sludges
Authors: Patoine Alain , Côté Raynald , Paquet Marcel
Published: March 2019

Detoxification of a chemi-thermomechanical pulp effluent (CTMP) was examined by monitoring toxicity and resin acid concentration during treatment in batch reactors. Two treatments were carried out — one performed with an industrial granular sludge and the other with a municipal anaerobic digester sludge. The two sludges were acclimated to the CTMP effluent by successive 6-day suspended growth cycles on fresh effluent. In both cases, several growth cycles showed resin acid and toxicity increases, probably caused by resin acid desorption from bacterial cell walls to the aqueous phase. Detoxification of the effluent was achieved with both sludges during the last growth cycle. Since measurements were performed on filtered samples, the observed decreases of toxicity and resin acid concentration may be the result of bacterial degradation or of adsorption of toxic substances on particulate matter. Major increases of resin acid were associated with major toxicity increases within one given growth cycle.
Release of Arsenic from Model Wastewater Treatment Solids: A Mechanism Based on Surface Ligand Exchange
Authors: Paige C.R. , Snodgrass W.J. , Nicholson Ronald V. , Sharer J.M.
Published: March 2019

The loss of arsenic from model wastewater treatment solids has been studied by neutron activation analysis. The data show that the loss of arsenic from unstirred solids is controlled by a surface exchange reaction and also clearly demonstrate that arsenic is not retained in a solid solution. This is in contrast to metal ions which are retained in crystalline solids as solid solutions. The activation energy Eafor the exchange reaction is calculated to be 40 kJ/mol. Data were retrieved for the half-time of arsenic exchanging from these solids. The presence of arsenic, either in the solid or in the aqueous phase contacting the solid, altered the kinetics of transformation to and the crystalline nature of the final products. These data have implications for the disposal of wastes to landfill.
Possibilités et limites des bassins lagunaires dans l’épuration des eaux usées
Authors: Bontoux J. , Picot B.
Published: March 2019

Les techniques d’épuration des eaux usées par lagunage correspondent à des procédés très diversifiés dont la conception doit être parfaitement adaptée à chaque problème posé dans un contexte climatique particulier. Les possibilités des systèmes épurateurs sont grandement fonction de leur gestion qui doit particulièrement tenir compte des cycles saisonniers et parfois aussi des cycles nycthéméraux. Les limites sont étroitement dépendantes des mauvaises conditions de l’éclairement hivernal. L’exposé des résultats d’un programme expérimental sur le lagunage à haut rendement algal illustre la complexité du fonctionnement d’un système lagunaire même simplifié et montre les possibilités d’amélioration des performances offertes par une gestion séquentielle des rejets d’eau traitée hors des bassins.
Transformation of the Herbicide Diclofop-Methyl in a Large-Scale Physical Aquifer Model
Authors: Headley J.V. , Lawrence J.R. , Zanyk B.N. , Brooks Paul W.
Published: March 2019

Products arising from the transformation of diclofop-methyl were studied under isothermal steady-state conditions in a meso-scale aquifer model. In general, the transformation products observed for the model were similar to those previously reported for field experiments. Some significantly different products were observed for the model in which there were: (i) preferential formation of 4-(2,4-dichlorophenoxy)dehydrophenetole instead of the analogous 4-(2,4-dichlorophenoxy)phenetole and 4-(2,4-dichlorophenoxy)-phenol, and (ii) formation of chlorinated metabolites of benzoic acid. Although the latter chlorinated metabolites were formed by an unknown process, the mechanism appears to occur via interactions with ubiquitous contaminants present in the soil. Formation of the polar chlorinated metabolites was linked to the prevalence of phthalate esters in environmental samples. Based on increased polarity, the latter chlorinated metabolites were predicted to be more mobilized in the presence of water than the parent herbicide.
Toxicity of Sulfite and Cadmium to Anaerobic Granular Sludge
Authors: Shew C.F. , Kosaric N.
Published: March 2019

Toxicity of sulfite (Na2SO3) and cadmium (CdCl2) ions to anaerobic granular sludge was investigated in 1.2 litre bench-scale upflow anaerobic sludge blanket (UASB) reactors during process acclimation and shock load conditions. Minimal sulfite toxicity was observed under gradual and shock load conditions at sulfite concentrations of up to 1000 mg S/L if proper acclimation was allowed to occur. No long-term toxic effects were observed although the COD digestion rate was temporarily inhibited by shock load of sulfite. Scanning electron micrographs indicated that more sulfate-reducing bacteria were present in the granules developed in the reactors with sulfite supplement although rod-shaped Methanosaeta-like bacteria were still dominant. High bacterial growth rate was observed in the reactors which were supplied with the feed containing sulfite. The COD digestion rate was inhibited at a cadmium loading rate of 2.4 g Cd per day under both acclimation and shock load conditions. Acclimation did not seem to improve the bacteria to tolerate the toxicity of cadmium. The concentration of free cadmium was very low in the reactors under normal conditions, but increased rapidly when the COD digestion in the reactors ceased. The bacteria could not be reactivated after inhibited by cadmium. When reactors were operated at low specific COD loading rates, more inorganic precipitates were formed inside the granules which consequently settled faster.
Heavy Metal Pollution in Sediments and Waters of the Penang River, Malaysia
Authors: Seng Chye-Eng , Lim Poh-Eng , Chong Poh-Kim , Wong Lee-Mai
Published: March 2019

The concentrations of zinc, copper, lead and nickel in the Penang River and its tributaries were determined to assess the extent of heavy metal pollution, and to evaluate which compartment provides a better indicator for heavy metal pollution. The results indicate that the concentrations of total and non-residual heavy metals in sediments increase significantly towards the estuary of the river. This trend is, however, not obvious for heavy metals in the river water. The data indicate that assessment of heavy metal pollution in rivers could be made by using the data of heavy metal levels in river sediments. It is suggested that non-residual heavy metal levels in sediments give the best indication of anthropogenic input of heavy metals to river systems.
Photocatalytic Discolouration of Solutions of Reactive Dyes in the Presence of H2O2
Authors: Nansheng Deng , Shizhong Tian , Mei Xia
Published: March 2019

Tests for the photocatalytic degradation of solutions of three reactive dyes, Red M-5B, Procion Blue MX-R and Procion Black H-N, in the presence of H2O2 were carried out. When the solutions of the three reactive dyes were irradiated by UV or solar light, the colour of the solutions disappeared gradually. A statistical analysis of the test results indicated a linear relation between the concentration of dyes and the time of irradiation. The discolouration reaction of the solutions was of the first order. Rate equations for the discolouration reactions of dye solutions were developed.

The dark reactions or the dye solutions containing H2O2 were very slow, illustrating that the photochemical reaction played a very important role. It was demonstrated that UV light and solar light (300 to 380 nm) photolyzes the HO and that the resulting OH radical reacts with the dye molecules and destroys the chromophore.
A Nested-Grid Hydrodynamic/Pollutant Transport Model for Nearshore Areas in Hamilton Harbour
Authors: Tsanis Ioannis K. , Wu Jian
Published: March 2019

A nested-grid depth-averaged circulation model was developed and applied to three nearshore areas in Hamilton Harbour: the western basin, LaSalle Park waterfront and the northeastern shoreline. The grid sizes used were 100 m for the whole harbour, and 25 m for the three nearshore areas. General features of current circulation and horizontal mixing times under various wind directions and speeds were obtained for the whole harbour using the coarse-grid model. The fine-grid model (water elevations and current information on the open boundaries were obtained from the whole harbour model) then provided current patterns which were used to drive the pollutant transport model. Simulation results reveal that the current in the fine-grid model is close to the current from the coarse-grid model, while more detailed current structures are explored. The water elevations from the fine-grid model agree well with the elevations from the coarse-grid one. The impact of artificial islands was examined by studying changes in current patterns, pollutant peaks, exposure and flushing time in different locations of concern. The design proposed provides: (i) minimum change in the existing current patterns; (ii) avoidance of pollutant hot spots; and (iii) minimum changes in the flushing time of pollutants.
Chemistry of Snowmelt from an Urban Lysimeter
Authors: Westerström Göran
Published: March 2019

A 200-m2 lysimeter, representing an urban paved plot, was installed in Lulea, Sweden, instrumented and monitored during the 1986 snowmelt season. Hourly and daily flow-proportional composite samples of snowmelt were collected and analyzed for pH, Cl−, NO3− and SO42− ions. The fractionation of these parameters in snowmelt was observed, indicating low pH values and high concentrations of the ions studied in the early phases of snowmelt relative to the parent snow cover. The corresponding concentration factors ranged from 5 to 8. Fluxes of hydrogen ions in snowmelt showed high values during the early phases of snowmelt, commonly described as an early (first) pollutant flush. For this type of pollutant transport response, the pollution load could be effectively controlled by storing and/or treating the initial heavily polluted part of total snowmelt and allowing the rest to bypass the control facility. By storing and/or treating the first quarter of the total meltwater volume, almost two thirds of the total hydrogen ion load could be controlled.
Sorption of Cadmium and Nickel in Activated Sludge
Authors: Kodukula Prasad S. , Patterson James W. , Surampalli Rao Y.
Published: March 2019

Distribution of cadmium and nickel between operationally defined soluble and solid phases of activated sludge was investigated. The metal sorption process was characterized by describing it quantitatively as a function of time, pH and suspended solids concentration. Reversibility of the sorption process was studied by comparing metal adsorption and desorption edges. The effect of desorption kinetics on hysteresis of nickel was investigated. Equilibrium adsorption isotherms were developed for cadmium and nickel in activated sludge at different pH levels, and sorption capacity of solids and conditional stability constants for metals-sludge reactions were determined using the Langmuir adsorption model.
Prediction of Pesticide Leaching on a Watershed Basis: Methodology and Application
Authors: Reynolds W.D. , de Jong R. , van Wesenbeeck I.J. , Clemente R.S.
Published: March 2019

Methodology consisting of a numerical solute transport model (LEACHM), combined with geostatistical analysis (kriging) and a geographic information system (GIS), was developed to predict and characterize low-level, nonpoint source pesticide contamination of groundwater on a watershed basis. A preliminary test and evaluation of the methodology was conducted by applying it to the prediction of atrazine contamination of groundwater in the Grand River watershed in Southern Ontario. Atrazine loading to the groundwater was predicted to be highly variable spatially (CV = 164%), but low-level (0 to 2.5 mg atrazine/m2/year) and less than 2% of the surface application (150 mg atrazine/2/year). The predicted concentration of atrazine in the groundwater never exceeded the Canadian drinking water guideline of 60 ppb, but exceeded the 3 ppb U.S. EPA standard in about 27% of the watershed area. These predictions were in general agreement with recent groundwater survey results, which found that nonpoint source atrazine contamination of groundwater in the watershed was highly variable spatially and generally low-level, but occasionally exceeding the U.S. EPA standard. Although these preliminary results are encouraging, more development and testing of the methodology is required.
Investigation and Remediation of Groundwater Contamination at a Pesticide Facility — a Case Study
Authors: Carter R.S. , Stiebel W.H. , Nalasco P.J. , Pardieck D.L.
Published: March 2019

Soil and groundwater beneath a 22-year old agrichemical formulating and warehousing facility in Cambridge, Ontario, have been impacted with pesticides in addition to volatile organic and nitrosoamine compounds associated with their formulation. Thirty-three compounds, including 15 pesticides released to the soil from an underground process wastewater system, concrete-lined pits, storage areas and infrequent spills, are present in the water table at a depth of 10 m in overburden sediments. Groundwater flow in the overburden is complex and dissolved compound migration is influenced by spatially variable vertical hydraulic gradients induced from the underlying dolostone aquifer which is pumped by municipal supply wells located at distances ranging from 600 m to 1500 m from the site. One pesticide, metolachlor(2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-l-melhylethyl) acetamide), has been measured consistently above Ontario drinking water objectives in the overburden and at a depth of 30 to 39 m below ground surface in the bedrock aquifer adjacent to the site. A groundwater pump and treat system is operating and is controlling further off-site migration of dissolved compounds in the overburden, and treating the captured groundwater with granular activated carbon.
Mesocosms for Subsurface Research
Authors: Lawrence J.R. , Hendry M.J.
Published: March 2019

This article provides an overview of mesocosm research applied to investigations of subsurface processes. The nature of mesocosms and the mesocosm concept are defined and discussed as are the advantages and disadvantages of these systems. In general, a mesocosm meets the requirements of being of sufficient size to contain all the components of interest while permitting “natural” behaviour. It is implicit in the use of mesocosms that they act as a surrogate for the real ecosystem. However, the precise size of a mesocosm is difficult to define without a specific context. Details are provided on the construction, filling and instrumentation of subsurface mesocosms. This article also provides recent examples of applications of mesocosms to studies of biogeochemistry, waste disposal and fate and transport of a herbicide. In addition, a comparison of physical, chemical and microbial data from a mesocosm (diameter 2.44 m × 4.6 m) with a 3-m thick vadose zone and water table and its associated field site is made. Mesocosms provide the advantages of controlled environment, near steady-state conditions, and environmentally acceptable testing of the fate and effects of toxics. However, considerable research is required to optimize their size, instrumentation and expand their application to in situ conditions as well as the laboratory.
Seasonal Loadings of Atrazine and Metolachlor to a Southeastern Ontario River from Surface Runoff and Groundwater Discharge
Authors: Fischer J.D. , Apedaile B.E. , Vanclief L.K.
Published: March 2019

The Payne River in the South Nation River basin in eastern Ontario was continuously sampled for atrazine and metolachlor from April to October during 1991 and 1992, using a modified Quality Environment Ltd. automatic liquid sampler. The objectives of the study were to determine weekly flow proportional concentrations and loadings to the river, and to assess loadings during dry weather periods for evidence of contributions from groundwater discharge. In 1992, samples were also analyzed for desethylatrazine, the predominant residue of atrazine. The site southeast of Ottawa represented a watershed area of 182 km2. The maximum concentration of atrazine were recorded for the weeks ending May 29, 1991 (0.83 µg/L), and July 30, 1992 (1.20 µg/L. These values were approximately half the Canadian Water Quality Guideline for the Protection of Freshwater Aquatic Life (2 µg/L). Maximum concentrations of metolachlor were also recorded for these dates. Values were 0.43 µg/L and 0.26 µg/L, respectively, well below the Canadian Water Quality Guideline of 8 µg/L for the Protection of Freshwater Aquatic Life. Discharge data were used to calculate weekly loadings from the watershed, and seasonal loadings were compared with the results of a pesticide usage survey. Atrazine loadings to the Payne River as a percentage of atrazine applied during both cropping seasons were the same (0.13%) despite different discharge patterns. Metolachlor loadings were similar for both years and less than the value for atrazine. In 1991, 0.01% of the metolachlor applied to the study area reached the river during that cropping season. The corresponding value for 1992 was 0.03%. Atrazine loadings associated with carry-over from the previous cropping season were an important factor during the study period. Observed atrazine loading before application in a given year exceeded the loading for the entire cropping season of that year. The compounds were also present in river water under dry weather conditions, suggesting that in addition to surface runoff, groundwater is also a significant source of pesticides to the Payne River.
Spatial and Temporal Water Quality Trends in Severn Sound, Georgian Bay, since the Introduction of Phosphorus Control Guidelines: Nutrients and Phytoplankton, 1973 to 1991
Authors: Gemza A.F.
Published: March 2019

Severn Sound continues to exhibit signs of eutrophication despite initial identification of the problem in 1969 and the construction of several sewage treatment plants since then. In general, improvements in trophic state indicators have been marginal, suggesting that the sewage treatment plants have had limited success in controlling phosphorus concentrations. These discharges likely contributed to the increased total phosphorus levels and consequently the higher phytoplankton densities of the nearshore waters. Phytoplankton biovolumes were on average one order of magnitude higher than in the open waters of Lake Huron with mean summer biovolumes as high as 8.0 mm/L. Algal biovolumes were most dense in Penetang Bay, which experienced limited exchange with the main waters of the sound. No significant long-term trends were observed. Water clarity was declining significantly, however, at a rate of -0.60 to -0.78 m/year throughout the sound except in Sturgeon Bay. Total phosphorus levels were highly variable from year to year; however, concentrations from a 20-year perspective were declining in the open waters at a rate of 0.70 µg/L/year, but response was limited in nearshore areas. In Sturgeon Bay, mean annual euphotic zone total phosphorus as well as soluble reactive phosphorus levels declined by as much as 50% following the construction of a sewage treatment plant with tertiary treatment. Phytoplankton genera typical of eutrophic waters continued to dominate the algal assemblage but members indicative of mesotrophic conditions have become apparent in some areas of the sound.
Abundance and Spatio-Temporal Distribution of Young-of-the-Year Fishes in an Altered Embayment of Lake Huron
Authors: Leslie J.K. , Timmins C.A.
Published: March 2019

The ecology of young-of-the-year fishes in a small (318 ha) perturbed embayment in Severn Sound (Lake Huron) was studied for the period May to October from 1990 to 1993. Fishes were collected with a beach seine (0.3-mm mesh) and ichthyoplankton nets (0.5-mm mesh). The taxocene (17,500 specimens collected) consisted of 17 families and 31 taxa, and represented 9 ecological guilds. Most (24) taxa were found at the shore, whereas 12 taxa were collected in limnetic areas. Fish habitats were diverse and disjunctive; most fishes were associated with mixed submersed and emergent macrophytes. Relatively few fishes inhabited severely altered shoreline areas that lacked cover from predators. The assemblage may be considered as percid-centrarchid-cyprinid, with Alosa pseudoharengus sporadically co-dominant. The most common and abundant species were Lepomis gibbosus (30% of total catch) and Perca flavescens (24%).
Phosphorus and Metal Contaminant Transport in Two Southern Ontario Rivers: the Grand River and its Tributary, the Nith River
Authors: Mayer T. , Reyes E. Delos
Published: March 2019

Water samples and suspended sediments from two southern Ontario rivers, the Grand River and its tributary, the Nith River, were analyzed to investigate the role of suspended sediments in the transport of phosphorus and metals from tributaries. Water samples were analyzed for total suspended solids, total phosphorus, total dissolved phosphorus, chloride and heavy metal concentrations. Suspended sediments were analyzed for forms of phosphorus, total and organic carbon, and heavy metals. Concentrations of total phosphorus and heavy metals in water were elevated during high flows (spring snowmelt and episodes of intensive rain events), which are characterized by high concentrations of suspended solids. On average, about half of the total phosphorus in the water (60 and 54% in the Grand and Nith rivers, respectively) was transported in the particulate form, of which about 20% is in a form that would be potentially available for biological utilization upon depletion of soluble P. Biologically inert apatite-P accounted for 25 and 19% of the total particulate P in suspended sediments from the Grand and Nith rivers, respectively, indicating that between one-fifth and one-quarter of the tributary particulate P flux is of little environmental significance. This form of particulate P showed positive correlation with discharge, indicating increased contribution of this form of P during high flows due to the channel scouring and bank erosion. This finding has important implications for the refinement of P load calculations, since it is during the wet years that P loads to the Great Lakes exceed target loads stipulated by the Great Lakes Water Quality Agreement, mainly because of increased tributary P contributions.

Except for apatite-P in suspended sediments from the Grand River, no statistically significant intersite differences were found in water and sediment chemistry, suggesting that there are no important sources or sinks of available phosphorus and metals between the monitored sites. River inputs from sewage treatment plants and urban runoff appear to have little effect on water quality. The lack of significant site differentiation in suspended sediments chemistry also reflects the absence of any significant chemical and/or biological processing of particles in transit and the similarity of sediment sources.
Small Lake Water Chemistry in Southern Quebec
Authors: Papineau Madeleine
Published: March 2019

Small lakes are an important resource both in terms of number and habitat for aquatic biota. A winter survey of 25 small lakes (<5 ha) was carried out in the area northwest of Quebec City in December 1991 to assess the chemical status of these lakes in relation to acidic deposition. A large number (36%) of lakes in the <5 ha size class have very little acid neutralizing capacity and usually relatively high concentrations of aluminum. The average concentration of hydrogen ions, sulfates, aluminum, colour and dissolved organic carbon is higher in the group of lakes in the <5 ha size class than in a group of nearby lakes in the > 5 ha size class. The addition of chemical information from lakes in the <5 ha class to the estimates of number of lakes in different pH classes increases the proportion of lakes with a pH at or below 5.0 from 4 to 10% and that of lakes with a pH at or below 5.5 from 17 to 24%.
A Tier-Testing Strategy for Managing Programs of Environmental Effects Monitoring
Authors: Hodson P.V. , Munkittrick K.R. , Stevens R. , Colodey A.
Published: March 2019

A good environmental effects monitoring program (EEM) provides answers to clear, well-defined questions. The answers should be quantitative and lead directly to decisions about the effluent being studied and about further EEM studies. Preliminary studies should trigger more in-depth monitoring only when predefined thresholds are exceeded. When in-depth work suggests that further studies are unnecessary, there should be a return to a lower level of effort. These criteria lead directly to a tiered strategy for managing EEM that defines the sequence and choice of studies through successive cycles. The benefits of a tiered approach are (1) rules that all stakeholders can understand and comply with; (2) monitoring limited to that which is essential; and (3) assurance that all appropriate elements are included, but only when necessary. Within the context of the new pulp and paper EEM program, tier testing is an efficient, logical and systematic strategy for managing monitoring.
Étude préliminaire sur l’utilisation d’essais biochimiques pour le suivi opérationnel d’une unité de biofiltration
Authors: Le Bihan Yann , Lessard Paul , Lavoie Marc C.
Published: March 2019

L’applicabilité de tests biochimiques a été évaluée pour une éventuelle utilisation dans le cadre du suivi d’un procédé par biofiltration. Les eaux de lavage, issues de biofiltres d’une usine de la Communauté urbaine de Québec, ont été échantillonnées puis analysées pour certains tests biochimiques (déshydrogé-nase, adénosine triphosphate et hydrolases) et caractétistiques physico-chimiques. Les résultats obtenus montrent que les déshydrogénases et hydrolases pourraient servir comme outil de suivi et d’opération d’un biofiltre; ce qui ne semble pas le cas pour l’adénosine triphosphate. Une relation entre l’activité déshydrogénase et la performance du procédé, évaluée par le pourcentage d’enlèvement de la demande biochimique en oxygène a pu être établie. Différents types d’hydrolases, dont la présence semble reliée à la détérioration des performances du procédé, ont également été identifiés soit les (β-Glucosidase, (β-Glucuronidase, α-Galactosidase et une Estérase (pour les composés à 4 carbones). De plus, les résultats obtenus indiquent qu’il serait possible d’établir une prédiction de la performance variant entre 2 et 4 jours suivant l’essai biochimique.