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We examined the influence of Montreal wastewater treatment plant (WWTP) effluents on two top predators, Walleye (Sander vitreus) and Sauger (Sander canadensis), with a focus on δ15N isotopic signatures and per- and polyfluoroalkyl substances (PFAS). These two fish species were collected in the summer 2013 in the St. Lawrence River upstream and downstream from a major WWTP, as well as in background sites (semi-remote lakes). Most of the δ15N variations for Sauger and Walleye are attributable to 1) δ15N values of the primary producers and sewage-derived particulate organic matter (SDPOM) at the base of the trophic food chain, 2) agricultural activities combined with biogeochemical processes, and 3) food web length. δ15N was significantly lower in fish collected in the effluent-mixed water masses than other sites of the St. Lawrence River, attributed to the SDPOM of the WWTP effluent. Relative to the background sites, certain PFAS were present at much higher levels in the St. Lawrence River, with profiles dominated by perfluoroalkyl sulfonates (PFSA). However, PFSA profiles generally remained consistent along the St. Lawrence River. PFOS levels in fish from the St. Lawrence exceeded the current Federal Environmental Quality Guidelines for protecting piscivorous mammals or birds. However, the human chronic daily intake of PFOS remained below current thresholds suggested by national agencies.

International audience; This study aims to evaluate the anthropogenic pressure in the St. Lawrence River by assessing the relationships between chemical contamination of sediments and benthic community structure with the trait-based approach. Organic and inorganic contaminants as well as other sediment variables (sediment grain size, total organic carbon, nutrients, etc.) and benthic invertebrate assemblages were determined in 59 sites along the river. Biological and ecological traits of taxa were coded, taking into account regional dimate and ecosystem conditions. The aims of this study were to (1) describe the relationships between traits and macroinvertebrate taxa and identify homogeneous dusters of taxa with the same combinations of functional traits, (2) describe spatial patterns in traits of macroinvertebrates in the St. Lawrence River, (3) link trait-based metrics and site groups to sediment quality and (4) define a trait-based strategy for diagnosing the ecological quality of the St. Lawrence River. Seven groups of taxa sharing similar trait-category attributes were defined. Moreover, four groups of sites were identified using the 'K-mean' non-hierarchical clustering approach. The 'IndVal' method enabled us to specifically defined trait categories corresponding to site groups on the basis of their indicator value. The relative abundances of taxa from five functional groups significantly varied among site groups. For example, some indicator traits such as multivolline cycle, long life span, fixed dutches, tegumental respiration, asexual reproduction, and collector/gatherer feeding habit were associated to the most heavily polluted sites located in the Montreal harbour which showed the highest sediment concentrations in Pb. Zn and Cu. Three trait-based pressure-specific models were built, based on the random forest approach, for respectively (1) heavy metals. (2) BPCs and PAHs, and (3) TBTs occurring in the environment. These models could be applied to assess sediment quality using macroinvertebrate assemblages in a large Canadian river

International audience

International audience; Municipal effluents are recognized as major sources of pollutants that could compromise fish health and reproduction. The purpose of this study was to examine and compare the reproductive toxicity of low-and high-risk municipal effluents to fathead minnows (Pimephales promelas) exposed for 12 weeks in the laboratory. After the exposure period, reproductive success was determined by following changes in the total number of eggs, egg hatchability/survival and time to hatch. In parallel, the expression of the following was also assessed in adults to gain insights into the pathways involved in toxicity: estrogen receptor alpha (ERα), androgen receptor (Ar1), pregnane X receptor (PXR1), vitellogenin (VTG), CYP3A4 and 17β-hydroxysteroid dehydrogenase (HSD). The results revealed that in the high-and low-risk effluents, egg laying followed a biphasic response, with an initial increase in egg laying followed by a decrease at higher concentrations and stronger amplitudes with the high-risk effluent. Hatching success (i.e., release of viable fish fry) was directly proportional to the decrease in egg production with no hatching of viable fish at 10% and 20% for both effluents. VTG gene expression was significantly increased in females, reaching levels 4 and 3 orders of magnitude greater than in the controls for the high-and low-risk effluent, respectively. VTG gene expression was also found in males but at lower expression levels than for the females. The expression of ERα was significantly correlated with VTG levels, which suggests the presence of estrogenic compounds in municipal effluents. This was further supported by the increased expression of CYP3A4, which is involved in the biotransformation of steroid-like and pharmaceutical compounds. In conclusion, municipal effluents have the capacity to reduce reproduction in fathead minnows and involve estrogenic effects. The high-risk effluent generally displayed stronger effects than the low-risk effluent.

International audience

Dredging activities can have a number of potential impacts, such as changes in the hydrological regime and adverse effects on wildlife habitats. Inappropriate management of contaminated sediments may also lead to significant environmental risk. Most dredging projects must therefore undergo an environmental assessment before they are carried out, in order to protect the environment and optimize sediment management. Depending on the degree of contamination, the current management framework includes the use of additional assessment tools to evaluate the ecological risk associated with contaminated sediments. Hence, the ecological risk assessment (ERA) approach presented in this document fine-tunes the analytical process surrounding the assessment of open-water disposal of dredged material and improves the decision-making process. The assessment must answer the following question: “In the context of a specific dredging project, is open-water disposal of dredged sediments acceptable?” This ERA approach was developed using an ecotoxicological study on the St. Lawrence River that collected and characterized samples in the natural environment and incorporated data from literature on the St. Lawrence River. In order to obtain a chemical, toxicological and biological characterization of the sediments, two sampling campaigns were carried out: the first in the fall of 2004 and the second in the fall of 2005. During selection of the sampling stations, areas of sedimentation (fluvial lakes, port areas, mouths of tributaries, etc.) were preferred, since these areas are recognized as having the highest contaminant levels due to the accumulation of fine particles. The ERA approach is composed of two tiers. Tier 1 describes the procedure for detecting the level of sediment contamination by comparing the results of the chemical analyses to the sediment quality assessment criteria established for Quebec. Tier 2, when required, describes the procedure for assessing the toxicity of freshwater sediments based on laboratory toxicity tests (mortality and growth of Hyalella azteca and Chironomus riparius). Depending on the results of the ERA, there are two possible management options: (1) the sediments can be disposed of in open water or can be used for other purposes, for example for beneficial uses such as the creation of wildlife habitats or beach replenishment, provided that the receiving environment is not thereby adversely affected; or (2) open-water disposal is prohibited and another management option must be chosen. This document presents the process by which the ERA approach was developed as well as rules for applying this approach.; Il est reconnu que les activités de dragage peuvent, entre autres, engendrer des modifications du régime hydrologique et avoir des effets négatifs sur les habitats fauniques. En présence de sédiments contaminés, une gestion inappropriée peut entraîner des risques significatifs pour l’environnement. La plupart des projets de dragage doivent par conséquent faire l’objet d’une évaluation environnementale avant leur réalisation afin d’assurer la protection de l’environnement et d’optimiser la gestion des sédiments. En fonction du degré de contamination, le cadre de gestion actuel prévoit le recours à des outils d’évaluation complémentaires pour juger du risque écotoxicologique associé aux sédiments contaminés. Ainsi, la démarche d’évaluation du risque écotoxicologique (ERE) qui a été élaborée permet d’affiner le cheminement de l’analyse concernant l’évaluation du rejet en eau libre des déblais de dragage et d’améliorer le processus de prise de décision. L’évaluation doit donner une réponse à la question suivante : « Dans le contexte d’un projet de dragage spécifique, est-il acceptable de rejeter les sédiments dragués en eau libre? » Cette démarche d’ERE a été établie à l’aide d’une étude écotoxicologique relative au fleuve Saint-Laurent comprenant la collecte et la caractérisation d’échantillons en milieu naturel, et utilisant des données de la littérature concernant le fleuve. Afin d’obtenir une caractérisation chimique, toxicologique et biologique des sédiments, deux campagnes d’échantillonnage ont été réalisées : la première à l’automne 2004 et la seconde à l’automne 2005. Lors de la sélection des stations d’échantillonnage, les zones de sédimentation (lacs fluviaux, zones portuaires, embouchures de tributaires, etc.) ont été favorisées, puisqu’il est reconnu que les plus fortes teneurs en contaminants sont associées à ces zones en raison de l’accumulation de particules fines qui s’y produit. La démarche d’ERE est constituée de deux étapes. L’étape 1 décrit la procédure de dépistage du niveau de contamination des sédiments en comparant les résultats des analyses chimiques aux critères d’évaluation de la qualité des sédiments établis pour le Québec. Lorsqu’elle est requise, l’étape 2 décrit la procédure d’évaluation de la toxicité des sédiments d’eau douce à partir d’essais de toxicité réalisés en laboratoire (mortalité et croissance de Hyalella azteca et Chironomus riparius). Selon les résultats de l’ERE, deux options de gestion sont possibles : 1) les sédiments peuvent être rejetés en eau libre ou être utilisés à d’autres fins, par exemple pour des usages bénéfiques tels que la création d’habitats fauniques ou le rechargement de plages, dans la mesure où le dépôt ne contribue pas à détériorer le milieu récepteur ou; 2) le dépôt en eau libre est proscrit et il faudra choisir une autre option de gestion. L’élaboration de la démarche d’ERE de même que ses règles d’application sont présentées dans le présent document.

Dredging activities can have a number of potential impacts, such as changes in the hydrological regime and adverse effects on wildlife habitats. Inappropriate management of contaminated sediments may also lead to significant environmental risk. Most dredging projects must therefore undergo an environmental assessment before they are carried out, in order to protect the environment and optimize sediment management. Depending on the degree of contamination, the current management framework includes the use of additional assessment tools to evaluate the ecological risk associated with contaminated sediments. Hence, the ecological risk assessment (ERA) approach presented in this document fine-tunes the analytical process surrounding the assessment of open-water disposal of dredged material and improves the decision-making process. The assessment must answer the following question: “In the context of a specific dredging project, is open-water disposal of dredged sediments acceptable?” This ERA approach was developed using an ecotoxicological study on the St. Lawrence River that collected and characterized samples in the natural environment and incorporated data from literature on the St. Lawrence River. In order to obtain a chemical, toxicological and biological characterization of the sediments, two sampling campaigns were carried out: the first in the fall of 2004 and the second in the fall of 2005. During selection of the sampling stations, areas of sedimentation (fluvial lakes, port areas, mouths of tributaries, etc.) were preferred, since these areas are recognized as having the highest contaminant levels due to the accumulation of fine particles. The ERA approach is composed of two tiers. Tier 1 describes the procedure for detecting the level of sediment contamination by comparing the results of the chemical analyses to the sediment quality assessment criteria established for Quebec. Tier 2, when required, describes the procedure for assessing the toxicity of freshwater sediments based on laboratory toxicity tests (mortality and growth of Hyalella azteca and Chironomus riparius). Depending on the results of the ERA, there are two possible management options: (1) the sediments can be disposed of in open water or can be used for other purposes, for example for beneficial uses such as the creation of wildlife habitats or beach replenishment, provided that the receiving environment is not thereby adversely affected; or (2) open-water disposal is prohibited and another management option must be chosen. This document presents the process by which the ERA approach was developed as well as rules for applying this approach.; Il est reconnu que les activités de dragage peuvent, entre autres, engendrer des modifications du régime hydrologique et avoir des effets négatifs sur les habitats fauniques. En présence de sédiments contaminés, une gestion inappropriée peut entraîner des risques significatifs pour l’environnement. La plupart des projets de dragage doivent par conséquent faire l’objet d’une évaluation environnementale avant leur réalisation afin d’assurer la protection de l’environnement et d’optimiser la gestion des sédiments. En fonction du degré de contamination, le cadre de gestion actuel prévoit le recours à des outils d’évaluation complémentaires pour juger du risque écotoxicologique associé aux sédiments contaminés. Ainsi, la démarche d’évaluation du risque écotoxicologique (ERE) qui a été élaborée permet d’affiner le cheminement de l’analyse concernant l’évaluation du rejet en eau libre des déblais de dragage et d’améliorer le processus de prise de décision. L’évaluation doit donner une réponse à la question suivante : « Dans le contexte d’un projet de dragage spécifique, est-il acceptable de rejeter les sédiments dragués en eau libre? » Cette démarche d’ERE a été établie à l’aide d’une étude écotoxicologique relative au fleuve Saint-Laurent comprenant la collecte et la caractérisation d’échantillons en milieu naturel, et utilisant des données de la littérature concernant le fleuve. Afin d’obtenir une caractérisation chimique, toxicologique et biologique des sédiments, deux campagnes d’échantillonnage ont été réalisées : la première à l’automne 2004 et la seconde à l’automne 2005. Lors de la sélection des stations d’échantillonnage, les zones de sédimentation (lacs fluviaux, zones portuaires, embouchures de tributaires, etc.) ont été favorisées, puisqu’il est reconnu que les plus fortes teneurs en contaminants sont associées à ces zones en raison de l’accumulation de particules fines qui s’y produit. La démarche d’ERE est constituée de deux étapes. L’étape 1 décrit la procédure de dépistage du niveau de contamination des sédiments en comparant les résultats des analyses chimiques aux critères d’évaluation de la qualité des sédiments établis pour le Québec. Lorsqu’elle est requise, l’étape 2 décrit la procédure d’évaluation de la toxicité des sédiments d’eau douce à partir d’essais de toxicité réalisés en laboratoire (mortalité et croissance de Hyalella azteca et Chironomus riparius). Selon les résultats de l’ERE, deux options de gestion sont possibles : 1) les sédiments peuvent être rejetés en eau libre ou être utilisés à d’autres fins, par exemple pour des usages bénéfiques tels que la création d’habitats fauniques ou le rechargement de plages, dans la mesure où le dépôt ne contribue pas à détériorer le milieu récepteur ou; 2) le dépôt en eau libre est proscrit et il faudra choisir une autre option de gestion. L’élaboration de la démarche d’ERE de même que ses règles d’application sont présentées dans le présent document.

International audience; How macroinvertebrate respond to human disturbances can be characterized following two major approaches. The traditional taxonomic approach has been extensively used. Since the nineties, another approach based on functional traits has experienced and offer a better understanding of community-environment relationships and functioning of ecosystems facing human impacts. In this study, we assessed sediment quality in a large river in North America by exploring the relationships between chemical contamination and benthic community structure using the functional trait approach. This study was carried out in the St-Lawrence River, an essential waterway exposed to many anthropogenic stresses such as industrial and municipal wastewater or agricultural activities. Macroinvertebrates were collected in 59 sites. Organic, inorganic contaminants and sediments characteristics (grain size, organic matter, nutrient, etc) were measured in the whole sediment. Seventeen biological or ecological traits of taxa were coded, taking into account regional climate and ecosystem specificities. The goals of this study were: (1) to describe spatial patterns in functional traits of macroinvertebrate communities; (2) to determine relationships between trait combinations and taxonomic structure and (3) to link macroinvertebrate assemblages and trait combinations to environmental conditions and sediment quality.

International audience; How macroinvertebrate respond to human disturbances can be characterized following two major approaches. The traditional taxonomic approach has been extensively used. Since the nineties, another approach based on functional traits has been experiment and offer a better understanding of community-environment relationships and functioning of ecosystems facing human impacts. In this study, we assessed sediment quality in a large river in North America by exploring the relationships between chemical contamination and benthic community structure using the functional trait approach. This study was carried out in the St-Lawrence River, an essential waterway exposed to many anthropogenic stresses such as industrial and municipal wastewater or agricultural activities. Macroinvertebrates were collected in 59 sites. Organic and inorganic contaminants as well as sediments characteristics (grain size, organic matter, nutrient, etc) were measured in sediment. Seventeen biological or ecological traits of taxa were coded, taking into account regional climate and ecosystem specificities. The goals of this study were to: (1) link macroinvertebrate trait combinations to environmental conditions and (2) link trait combinations to quality guidelines developed for the assessment of sediment quality in Quebec.

International audience; This study is a part of a large research project aiming at developing an ERA tiered framework for sediment management, in the context of integrated management of contaminated sediment, site restoration and sustainable navigation. The purpose of this study is to assess sediment quality by exploring the relationships between chemical contamination and benthic community structure using classical taxonomy and functional traits approaches. During falls 2004-2005, macroinvertebrates were collected in 59 sites in the St. Lawrence River, especially in its three fluvial lakes and in the harbour zone of Montreal. Organic (PCBs, PAHs, petroleum hydrocarbons), inorganic (As, Cd, Cu, Cr, Hg, Ni, Pb and Zn) contaminants and sediments characteristics (e.g. grain size, metal-binding phases, nutrients) were measured in whole sediment. Taxonomy and functional traits of benthic macroinvertebrates in the St. Lawrence River will be used to assess the relative impact of chemical contamination and sediment characteristics applying multivariate analysis and variance partitioning. We will compare the potential of taxonomy and functional traits approaches for assessing sediment quality in comparison with chemical sediment quality guidelines classification. The preliminary results and the implication for the development of an ERA tiered framework will be discussed.

International audience; Many studies have showed that impact by chemical contamination on benthos can be hard to demonstrate in the presence of unmeasured factors. Although influence of some habitat characteristics has been identified in parts of the St. Lawrence River, the use of benthos to assess chemically degraded sites remains uncertain. The purpose of this study is to compare the potential of various benthic macroinvertebrates community indices (diversity, richness, biotic) for assessing sediment quality in comparison with chemical sediment quality guidelines classification. In an attempt to identify possibly key factors that could be weighing in on benthic macroinvertebrates community structure, we will also regroup sites based on prospect habitat characteristics. This study is a part of a large research project aiming at developing an ERA tiered framework for sediment management, in the context of integrated management of contaminated sediment, site restoration and sustainable navigation. During falls 2004-2005, macroinvertebrates were collected in 59 sites in the St. Lawrence River, especially in its three fluvial lakes and in the harbour zone of Montreal. Organic (PCBs, PAHs, petroleum hydrocarbons), inorganic (As, Cd, Cu, Cr, Hg, Ni, Pb and Zn) contaminants and sediments characteristics (e.g. grain size, metal-binding phases, nutrients) were measured in whole sediment. The preliminary results and the implication for the development of an ERA tiered framework will be discussed.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

International audience; The St. Lawrence River is one of the most world's largest watercourses. This river, an essential waterway for North America, is exposed to many anthropogenic stresses, as 97% of the Quebec population is living in its watershed. This study is a part of a large research project aiming at developing an ERA tiered framework for sediment management, in the context of integrated management of contaminated sediment, site restoration and sustainable navigation. The purpose of this study is to assess sediment quality by exploring the relationships between chemical contamination and benthic community structure using classical taxonomy and functional traits approaches. During falls 2004-2005, macroinvertebrates were collected in 59 sites in the St. Lawrence River, especially in its three fluvial lakes and in the harbour zone of Montreal. Organic (PCBs, PAHs, petroleum hydrocarbons), inorganic (As, Cd, Cu, Cr, Hg, Ni, Pb and Zn) contaminants and sediments characteristics (e.g. grain size, metal-binding phases, nutrients) were measured in whole sediment. Different descriptors (taxonomy and functional traits) of benthic macroinvertebrates in the St. Lawrence levels are used to assess the relative impact of chemical contamination and sediment characteristics on macroinvertebrate community, using multivariate analysis and variance partitioning. We compared the potential of taxonomy and functional traits approaches for assessing sediment contamination and toxicity. We also established sediment classification with different methods such as benthic community (taxonomy or traits), bioassay and chemical concentrations based on St. Lawrence River sediment quality guidelines. Implication for the development of an ERA tiered framework will be discussed. This research is being carried out within the context of a cooperation program involving the Groupe de Recherche Interuniversitaire en Limnologie et en Environnement Aquatique (GRIL) at the Université de Montréal, Environment Canada, the Ministère du Développement Durable, de l'Environnement et des Parcs du Québec, and Cemagref groupement de Lyon.

Project Report 2000-29