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Dr. Christian Gagnon
Aquatic Contaminants Research Division, Water Science and Technology Environment Canada, Montréal, QC, Canada

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0 Nanomaterials
0 Pharmaceuticals
0 Transformation
0 Wastewater
0 Bioaccumulation

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Journal article
Published: 29 July 2021 in Environmental Science and Pollution Research
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The occurrence of silver (Ag) in urban effluents is partly associated with the increasing use of silver nanoparticles (Ag NPs) as an antiseptic agent in various consumer products. Distinction among Ag forms must be taken into account in the assessment of exposure and toxicological effects to aquatic organisms. Wastewater treatment processes effectively remove Ag particles and colloids (mostly > 95%), but this still leaves notable concentrations (in order of ng/L) escaping to effluent-receiving waters. Total suspended Ag concentrations in various studied effluents ranged from 0.1 to 6 ng/L. The purpose of this study was then to measure and characterize Ag NPs in urban effluents for their concentrations and size distribution using the single particle ICP-MS technique (SP-ICP-MS). Wastewater influents and effluents from various treatment plants—from aerated lagoons to advanced treatment technology—were collected for three sampling days. Our results showed the presence of Ag NP in all samples with concentrations reaching 0.5 ng/L on a mass basis. However, on a particle number basis, Ag NP concentrations (expressed in particle/mL) in the 20–34-nm fraction (up to 3400 particles/mL) were much more abundant (> 700%) than in the > 35-nm larger fraction. The proportion of Ag at the nanoscale (1–100 nm) represents less than 8% of the total suspended Ag for all effluent samples, regardless of their origins. A significant correlation (linear regression: r 2 > 0.7) was observed between Ag NP and total suspended Ag concentrations in investigated effluents. Because Ag nanotoxicity is size dependent, the determination of size distribution and exposure concentration on a particle number basis is urgently needed for risk assessment of this class of nanoparticles.

ACS Style

Christian Gagnon; Patrice Turcotte; François Gagné; Shirley Anne Smyth. Occurrence and size distribution of silver nanoparticles in wastewater effluents from various treatment processes in Canada. Environmental Science and Pollution Research 2021, 1 .

AMA Style

Christian Gagnon, Patrice Turcotte, François Gagné, Shirley Anne Smyth. Occurrence and size distribution of silver nanoparticles in wastewater effluents from various treatment processes in Canada. Environmental Science and Pollution Research. 2021; ():1.

Chicago/Turabian Style

Christian Gagnon; Patrice Turcotte; François Gagné; Shirley Anne Smyth. 2021. "Occurrence and size distribution of silver nanoparticles in wastewater effluents from various treatment processes in Canada." Environmental Science and Pollution Research , no. : 1.

Journal article
Published: 12 December 2020 in Environments
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The toxicological effects of nanoparticles mixtures in aquatic organisms are poorly understood. The purpose of this study was to examine the tissue metal loadings and sublethal effects of silver (nAg), cerium oxide (nCeO), copper oxide (nCuO) and zinc oxide (nZnO) nanoparticles individually at 50 µg/L and in two mixtures to freshwater mussels Dreissena bugensis. The mixtures consisted of 12.5 µg/L of each nanoparticle (Mix50) and 50 µg/L of each nanoparticles (Mix200). After a 96-h exposure period, mussels were analyzed for morphological changes, air time survival, bioaccumulation, inflammation (cyclooxygenase or COX activity), lipid peroxidation (LPO), DNA strand breaks, labile Zn, acetylcholinesterase (AChE) and protein–ubiquitin levels. The data revealed that mussels accumulated the nanoparticles with nCeO and nAg were the least and most bioavailable, respectively. Increased tissue metal loadings were observed for nCeO and nCuO in mixtures, while no mixture effects were observed for nAg and nZnO. The weight loss during air emersion was lower in mussels exposed to nCuO alone but not by the mixture. On the one hand, labile Zn levels was increased with nZnO but returned to control values with the Mix50 and Mix200, suggesting antagonism. On the other hand, DNA strand breaks were reduced for both mixtures compared to controls or to the nanoparticles individually, suggesting potentiation of effects. The same was found for protein–ubiquitin levels, which were decreased by nCeO and nCuO alone but not when in mixtures, which increased their levels. In conclusion, the data revealed that the behavior and effects of nanoparticles were influenced by other nanoparticles where antagonist and potentiation interactions were identified.

ACS Style

Joelle Auclair; Patrice Turcotte; Christian Gagnon; Caroline Peyrot; Kevin J. Wilkinson; François Gagné. Toxicological Effects of Inorganic Nanoparticle Mixtures in Freshwater Mussels. Environments 2020, 7, 109 .

AMA Style

Joelle Auclair, Patrice Turcotte, Christian Gagnon, Caroline Peyrot, Kevin J. Wilkinson, François Gagné. Toxicological Effects of Inorganic Nanoparticle Mixtures in Freshwater Mussels. Environments. 2020; 7 (12):109.

Chicago/Turabian Style

Joelle Auclair; Patrice Turcotte; Christian Gagnon; Caroline Peyrot; Kevin J. Wilkinson; François Gagné. 2020. "Toxicological Effects of Inorganic Nanoparticle Mixtures in Freshwater Mussels." Environments 7, no. 12: 109.

Journal article
Published: 23 October 2020 in Talanta
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Anabaenopeptins (APs) are bioactive cyanopeptides of emerging concern produced by cyanobacteria. The research for analytical development has recently gained in importance due to their abundance in toxic cyanobacterial blooms. A new commercial enzyme-linked immunosorbent assay kit for the determination of total APs (APtot ELISA) has been released promising a rapid response with good cost efficiency for the routine monitoring of uncommon cyanopeptides. The present study explores the suitability of this new kit in comparison with a validated quantitative analytical method based on liquid chromatography coupled to mass spectrometry (LC-MS). The validation results were comparable with both methods for accuracy, precision, and calibration. Method detection limits were more sensitive using LC-MS specifically evaluated at 0.011 and 0.013 μg L−1 for AP-A and B respectively, compared to APtot ELISA evaluated at 0.10 μg L−1 for total of the two. For APtot ELISA, results were independent from the matrix; however, a systematic signal response was measured in blanks, requiring a blank subtraction in data treatment. Cross-reactivity of APtot ELISA was investigated by analyzing ten cyanopeptides selected for their abundance and diversity. Cyanopeptolin A (CP-A), nodularin-R (NOD), microcystin (MC)-RR, [Asp3]RR, and HilR showed cross-reactivity with an average overestimation going from 25 to 66%. Considering the contribution of cross-reactive cyanopeptides, thirteen lake samples out of fifteen showed higher concentrations using APtot ELISA with overestimation values up to 2261% compared to LC-MS. In light of this study results, LC-MS should still be preconized for the study and monitoring of APs when sensitivity and specificity are needed.

ACS Style

Audrey Roy-Lachapelle; Morgan Solliec; Sébastien Sauvé; Christian Gagnon. Evaluation of ELISA-based method for total anabaenopeptins determination and comparative analysis with on-line SPE-UHPLC-HRMS in freshwater cyanobacterial blooms. Talanta 2020, 223, 121802 .

AMA Style

Audrey Roy-Lachapelle, Morgan Solliec, Sébastien Sauvé, Christian Gagnon. Evaluation of ELISA-based method for total anabaenopeptins determination and comparative analysis with on-line SPE-UHPLC-HRMS in freshwater cyanobacterial blooms. Talanta. 2020; 223 ():121802.

Chicago/Turabian Style

Audrey Roy-Lachapelle; Morgan Solliec; Sébastien Sauvé; Christian Gagnon. 2020. "Evaluation of ELISA-based method for total anabaenopeptins determination and comparative analysis with on-line SPE-UHPLC-HRMS in freshwater cyanobacterial blooms." Talanta 223, no. : 121802.

Research article
Published: 26 May 2020 in Environmental Science and Pollution Research
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Benthic cyanobacterial mats occurring in the St. Lawrence River fluvial lakes Saint-Louis and Saint-Pierre are dominated by Microseira (Lyngbya) wollei which produce several cyanotoxins including LWTX-1 that is characteristic of Microseira wollei. This cyanotoxin is not only present in the filaments forming benthic mats, but was also measured in the water overlying the mats. LWTX-1 was found in all cyanobacterial filament samples (75.29–103.26 ng mg−1) and all overlying water samples (3.01–11.03 ng L−1). Toxin concentrations measured in overlying water and dry biomass were strongly correlated (r = 0.94). Furthermore, LWTX-1 concentration in water was positively correlated with the dissolved organic carbon in water (r = 0.74) and % nitrogen content in cyanobacterial filaments (r = 0.52). A preliminary study was conducted to determine the release and degradation rates of LWTX-1 from a M. wollei mat kept under laboratory conditions over a 3-month period. Toxin measurements revealed an early, massive toxin release followed by a typical decaying function, with a half-life in the order of 17 days. Our results raise concerns about the occurrence and downstream advection of dissolved cyanotoxins from Microseira mats in the aquatic environment.

ACS Style

Sylvie Poirier-Larabie; Christiane Hudon; Hugo-Pierre Poirier Richard; Christian Gagnon. Cyanotoxin release from the benthic, mat-forming cyanobacterium Microseira (Lyngbya) wollei in the St. Lawrence River, Canada. Environmental Science and Pollution Research 2020, 27, 30285 -30294.

AMA Style

Sylvie Poirier-Larabie, Christiane Hudon, Hugo-Pierre Poirier Richard, Christian Gagnon. Cyanotoxin release from the benthic, mat-forming cyanobacterium Microseira (Lyngbya) wollei in the St. Lawrence River, Canada. Environmental Science and Pollution Research. 2020; 27 (24):30285-30294.

Chicago/Turabian Style

Sylvie Poirier-Larabie; Christiane Hudon; Hugo-Pierre Poirier Richard; Christian Gagnon. 2020. "Cyanotoxin release from the benthic, mat-forming cyanobacterium Microseira (Lyngbya) wollei in the St. Lawrence River, Canada." Environmental Science and Pollution Research 27, no. 24: 30285-30294.

Journal article
Published: 26 October 2019 in Toxins
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Toxin-producing cyanobacteria are responsible for the presence of hundreds of bioactive compounds in aquatic environments undergoing increasing eutrophication. The identification of cyanotoxins is still emerging, due to the great diversity of potential congeners, yet high-resolution mass spectrometry (HRMS) has the potential to deepen this knowledge in aquatic environments. In this study, high-throughput and sensitive on-line solid-phase extraction ultra-high performance liquid chromatography (SPE-UHPLC) coupled to HRMS was applied to a data-independent acquisition (DIA) workflow for the suspect screening of cyanopeptides, including microcystin and anabaenopeptin toxin classes. The unambiguous characterization of 11 uncommon cyanopeptides was possible using a characterization workflow through extensive analysis of fragmentation patterns. This method also allowed the characterization of four unknown cyanotoxins ([Leu1, Ser7] MC-HtyR, [Asp3]MC-RHar, AP731, and AP803). The quantification of 17 common cyanotoxins along with the semi-quantification of the characterized uncommon cyanopeptides resulted with the identification of 23 different cyanotoxins in 12 lakes in Canada, United Kingdom and France. The concentrations of the compounds varied between 39 and 41,000 ng L−1. To our knowledge, this is the first DIA method applied for the suspect screening of two families of cyanopeptides simultaneously. Moreover, this study shows the great diversity of cyanotoxins in lake water cyanobacterial blooms, a growing concern in aquatic systems.

ACS Style

Audrey Roy-Lachapelle; Morgan Solliec; Sébastien Sauvé; Christian Gagnon. A Data-Independent Methodology for the Structural Characterization of Microcystins and Anabaenopeptins Leading to the Identification of Four New Congeners. Toxins 2019, 11, 619 .

AMA Style

Audrey Roy-Lachapelle, Morgan Solliec, Sébastien Sauvé, Christian Gagnon. A Data-Independent Methodology for the Structural Characterization of Microcystins and Anabaenopeptins Leading to the Identification of Four New Congeners. Toxins. 2019; 11 (11):619.

Chicago/Turabian Style

Audrey Roy-Lachapelle; Morgan Solliec; Sébastien Sauvé; Christian Gagnon. 2019. "A Data-Independent Methodology for the Structural Characterization of Microcystins and Anabaenopeptins Leading to the Identification of Four New Congeners." Toxins 11, no. 11: 619.

Journal article
Published: 01 January 2018 in Journal of Nanomedicine & Nanotechnology
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ACS Style

Christian Gagnon; Bruneau A; Turcotte P; Pilote M; Gagné F. Fate of Cerium Oxide Nanoparticles in Natural Waters and Immunotoxicity in Exposed Rainbow Trout. Journal of Nanomedicine & Nanotechnology 2018, 9, 1 -8.

AMA Style

Christian Gagnon, Bruneau A, Turcotte P, Pilote M, Gagné F. Fate of Cerium Oxide Nanoparticles in Natural Waters and Immunotoxicity in Exposed Rainbow Trout. Journal of Nanomedicine & Nanotechnology. 2018; 9 (2):1-8.

Chicago/Turabian Style

Christian Gagnon; Bruneau A; Turcotte P; Pilote M; Gagné F. 2018. "Fate of Cerium Oxide Nanoparticles in Natural Waters and Immunotoxicity in Exposed Rainbow Trout." Journal of Nanomedicine & Nanotechnology 9, no. 2: 1-8.

Journal article
Published: 01 November 2017 in Journal of Chromatography A
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Aquatic systems near major urban centers are constantly contaminated with effluent from wastewater treatment plants. Pharmaceuticals are part of the contamination and several classes of drugs have been detected in surface waters in the last decade. To better understand the impact of those pharmaceuticals in ecosystems, the exposure to aquatic species needs to be investigated. This study presents a new simple and rugged quantitative method for the determination of several classes of drugs using 100μL of plasma from fish environmentally exposed to a major but highly diluted urban effluent. Six common drugs (i.e., diclofenac, ibuprofen, naproxen, salbutamol, sulfamethoxazole and trimethoprim) and one major metabolite (2-hydroxy-ibuprofen), present in significant amount in impacted waterways have been selected for the development and validation of the method. First, all drugs were extracted using cation exchange solid phase extraction (SPE) and eluted with two solvent mixtures. Then, the extracts were analyzed using a reverse-phase analytical column Waters(®) CORTECS C18+ (150×2.1mm, 2.7μm) within 14min. MS/MS was performed with an electrospray (ESI) interface in positive ion mode, with multiple reaction monitoring (MRM) experiment acquiring two product ions per drugs. Quantification has been made with standard curves for each analyte using isotopically labeled internal standards. This method has high sensitivity with limits of quantification of 1ngmL(-1) for each drug, except for ibuprofen and its metabolite 2-hydroxy-ibuprofen at 2ngmL(-1). The precision of the method was below 11%, the accuracy between 94 and 105% and overall recovery between 94 and 111% for all drugs, with high selectivity. Application of the method to plasma samples from wild northern pike inhabiting the St. Lawrence River collected over a three-year period showed the presence of naproxen, diclofenac, trimethoprim and salbutamol at very low concentrations (around 1ngmL(-1)).

ACS Style

S. Poirier Larabie; M. Houde; C. Gagnon. Determination of the bioavailability of selected pharmaceutical residues in fish plasma using liquid chromatography coupled to tandem mass spectrometry. Journal of Chromatography A 2017, 1522, 48 -55.

AMA Style

S. Poirier Larabie, M. Houde, C. Gagnon. Determination of the bioavailability of selected pharmaceutical residues in fish plasma using liquid chromatography coupled to tandem mass spectrometry. Journal of Chromatography A. 2017; 1522 ():48-55.

Chicago/Turabian Style

S. Poirier Larabie; M. Houde; C. Gagnon. 2017. "Determination of the bioavailability of selected pharmaceutical residues in fish plasma using liquid chromatography coupled to tandem mass spectrometry." Journal of Chromatography A 1522, no. : 48-55.

Conference report
Published: 28 April 2017 in Journal of Xenobiotics
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Nearly 5 billion liters of untreated sewage was intentionally discharged in November 2015 in the St. Lawrence River (Canada) for reasons of major sewer system maintenance and to avoid jeopardizing the Montreal wastewater treatment plant

ACS Style

C. Gagnon; Martin Pilote; P. Turcotte; C. André. Metal Contamination of the St. Lawrence River Following a Major Release of Untreated Wastewater. Journal of Xenobiotics 2017, 7, 21 -24.

AMA Style

C. Gagnon, Martin Pilote, P. Turcotte, C. André. Metal Contamination of the St. Lawrence River Following a Major Release of Untreated Wastewater. Journal of Xenobiotics. 2017; 7 (1):21-24.

Chicago/Turabian Style

C. Gagnon; Martin Pilote; P. Turcotte; C. André. 2017. "Metal Contamination of the St. Lawrence River Following a Major Release of Untreated Wastewater." Journal of Xenobiotics 7, no. 1: 21-24.

Journal article
Published: 01 October 2016 in Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology
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Nanoparticles released into the environment could pose a risk to resident organisms that feed on suspended particles in aquatic ecosystems. The purpose of this study was to examine the effects of silver nanoparticles ananoAg) of different sizes in freshwater mussels using a multi-elemental (metallomic) approach in order to determine signature effects of nanoparticulate and ionic Ag. Mussels were exposed to three concentrations (0.8, 4 and 20 μg/L) of 20-nm and 80-nm nanoAg and AgNO3 for 48 h at 15 °C. After the exposure period, mussels were placed in clean, aerated water for a depuration step and analyzed for the following total elements in gill, digestive gland and gonad tissues: Al, Ag, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Pb, Na, Ni, Se, Sr, Th, U, V and Zn. Metallothioneins (MT; digestive gland only) and lipid peroxidation (LPO) were also determined in gills, digestive glands and gonads. The 20-nm-diameter nanoAg was detected in all three tissues at 20 μg/L, while the 80-nm nanoAg was detected more strongly in the digestive gland. Ionic Ag was found at higher levels in gills than in other tissues. Correlation analysis revealed that gonad Ag levels were significantly correlated with Al (r = 0.28), V (r = 0.28), Cr (r = 0.31), Co (r = 0.32), Se (r = 0.34) and MT levels (R = 0.28). Indeed, the MT levels in the digestive gland were significantly increased by 20-nm nanoAg (20 μg/L) and 80-nm nanoAg (4 μg/L) and AgNO3 (< 0.8 μg/L). LPO was observed in gills, digestive glands and even gonads for all Ag forms. Discriminant function analysis revealed that all forms of Ag differed from each other and from unexposed mussels, where ionic Ag was more closely related to the 80-nm-diameter nanoAg. Factorial analysis revealed that Ba, Ca, Co, Mn, Sr, U and Zn had consistently high factorial weights in all tissues; that explained 80% of the total variance. Moreover, the following elements showed strong correlations (r > 0.7) with each other: Sr, Ba, Zn, Ca, Mg Cr, Mn and U. Comparisons of these elements with other elements showing low or no correlations (transition elements) revealed that these elements had significantly lower standard reduction potential and electronegativity, suggesting that stronger reducing elements were most influenced by the oxidizing effects of nanoAg and ionic Ag in tissues. Indeed, tissues with oxidative stress (LPO) had decreased levels for most of these reducing elements. We conclude that exposure to Ag nanoparticles produces a characteristic change in the elemental composition of gills, digestive gland and gonad tissues in freshwater mussels. Elements most responsive to oxidative stress were more influenced by both nanoAg and ionic Ag. Sr and Ba were readily decreased by Ag and appeared to respond more sensitively to nanoAg than to ionic Ag. The metallomic approach could contribute in the understanding of fundamental mode of action of nanoparticles in mussels.

ACS Style

Francois Gagne; P. Turcotte; Martin Pilote; J. Auclair; C. André; C. Gagnon. Elemental profiles of freshwater mussels treated with silver nanoparticles: A metallomic approach. Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology 2016, 188, 17 -23.

AMA Style

Francois Gagne, P. Turcotte, Martin Pilote, J. Auclair, C. André, C. Gagnon. Elemental profiles of freshwater mussels treated with silver nanoparticles: A metallomic approach. Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology. 2016; 188 ():17-23.

Chicago/Turabian Style

Francois Gagne; P. Turcotte; Martin Pilote; J. Auclair; C. André; C. Gagnon. 2016. "Elemental profiles of freshwater mussels treated with silver nanoparticles: A metallomic approach." Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology 188, no. : 17-23.

Journal article
Published: 01 July 2016 in Science of The Total Environment
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Contamination of the aquatic environment by pharmaceuticals via urban effluents is well known. Several classes of drugs have been identified in waterways surrounding these effluents in the last 15 years. To better understand the fate of pharmaceuticals in ecosystems, degradation processes need to be investigated and transformation products must be identified. Thus, this study presents the first comparative study between three different natural environmental conditions: photolysis and biodegradation in aerobic and anaerobic conditions both in the dark of diclofenac and sulfamethoxazole, two common drugs present in significant amounts in impacted surface waters. Results indicated that degradation kinetics differed depending on the process and the type of drug and the observed transformation products also differed among these exposure conditions. Diclofenac was nearly degraded by photolysis after 4 days, while its concentration only decreased by 42% after 57 days of exposure to bacteria in aerobic media and barely 1% in anaerobic media. For sulfamethoxazole, 84% of the initial concentration was still present after 11 days of exposure to light, while biodegradation decreased its concentration by 33% after 58 days of exposure under aerobic conditions and 5% after 70 days of anaerobic exposure. In addition, several transformation products were observed and persisted over time while others degraded in turn. For diclofenac, chlorine atoms were lost primarily in the photolysis, while a redox reaction was promoted by biodegradation under aerobic conditions. For sulfamethoxazole, isomerization was favored by photolysis while a redox reaction was also favored by the biodegradation under aerobic conditions. To summarize this study points out the occurrence of different transformation products under variable degradation conditions and demonstrates that specific functional groups are involved in the tested natural attenuation processes. Given the complexity of environmental samples more analytical effort is needed to fully identify new products of potential toxicity.

ACS Style

S. Poirier-Larabie; Pedro Alejandro Segura; C. Gagnon. Degradation of the pharmaceuticals diclofenac and sulfamethoxazole and their transformation products under controlled environmental conditions. Science of The Total Environment 2016, 557-558, 257 -267.

AMA Style

S. Poirier-Larabie, Pedro Alejandro Segura, C. Gagnon. Degradation of the pharmaceuticals diclofenac and sulfamethoxazole and their transformation products under controlled environmental conditions. Science of The Total Environment. 2016; 557-558 ():257-267.

Chicago/Turabian Style

S. Poirier-Larabie; Pedro Alejandro Segura; C. Gagnon. 2016. "Degradation of the pharmaceuticals diclofenac and sulfamethoxazole and their transformation products under controlled environmental conditions." Science of The Total Environment 557-558, no. : 257-267.

Journal article
Published: 01 July 2016 in Harmful Algae
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The concentration of the saxitoxin analogue LWTX-1 was quantified in samples of the benthic filamentous cyanobacterium Lyngbya wollei (Farlow ex Gomont) Speziale and Dyck collected in two fluvial lakes of the St. Lawrence River (Canada) over the 2006\u20132013 period. The study was aimed at documenting the spatial (between fluvial lakes, between sites within each lake) and temporal (interannual, monthly) variations of toxin concentration in relation with hydrological (water level), physical (water temperature, conductivity, transparency), chemical (nutrients in overlying water) and biological (L. wollei biomass and mat condition) characteristics. Toxin concentration was hypothesized to vary seasonally with biomass accumulation and environmental conditions. Toxin concentrations measured in Lake Saint-Louis (51 +/- 40 mg LWTX-1 g-1 DM, N = 29 days in 2007, 2009\u20132011) were double those in Lake Saint-Pierre (25 +/- 31 mg LWTX-1 g-1 DM, N = 26 days in 2006\u20132008, 2012\u20132013); however, August 2007 measurements taken from both lakes did not differ significantly. Ten of the twelve highest values (>100 mg LWTX-1 g-1 DM) were obtained from Lake Saint-Louis, between April and October in 2007, 2010 or 2011. Under ice samples showed intermediate concentrations of LWTX-1 (42 +/- 9 mg LWTX-1 g-1 DM, N = 2). Concentrations of LWTX-1 were positively correlated with Secchi depth (r = 0.59, p < 0.001), L. wollei biomass (Spearman r = 0.31, p < 0.01) and %N in filaments (r = 0.48, p < 0.001), suggesting toxin production was linked to mat growth and metabolism rather than water quality. Although LWTX-1 has been reported to have a low toxicity, monitoring of L. wollei abundance is required to assess the environmental and human health risks posed by this taxon in the St. Lawrence - Great Lakes system.Peer reviewed: YesNRC publication: Ye

ACS Style

C. Hudon; P. Gagnon; S. Poirier Larabie; C. Gagnon; A. Lajeunesse; M. Lachapelle; Michael Quilliam. Spatial and temporal variations of a saxitoxin analogue (LWTX-1) in Lyngbya wollei (Cyanobacteria) mats in the St. Lawrence River (Québec, Canada). Harmful Algae 2016, 57, 69 -77.

AMA Style

C. Hudon, P. Gagnon, S. Poirier Larabie, C. Gagnon, A. Lajeunesse, M. Lachapelle, Michael Quilliam. Spatial and temporal variations of a saxitoxin analogue (LWTX-1) in Lyngbya wollei (Cyanobacteria) mats in the St. Lawrence River (Québec, Canada). Harmful Algae. 2016; 57 ():69-77.

Chicago/Turabian Style

C. Hudon; P. Gagnon; S. Poirier Larabie; C. Gagnon; A. Lajeunesse; M. Lachapelle; Michael Quilliam. 2016. "Spatial and temporal variations of a saxitoxin analogue (LWTX-1) in Lyngbya wollei (Cyanobacteria) mats in the St. Lawrence River (Québec, Canada)." Harmful Algae 57, no. : 69-77.

Original articles
Published: 03 July 2013 in Journal of Toxicology and Environmental Health, Part A
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The purpose of this study was to examine the effects of Ag nanoparticles (nAg) of two different sizes (20 and 80 nm) and Ag(+) on the immune system of the freshwater mussel Elliptio complanata. Mussels were exposed to increasing concentrations of nAg and dissolved Ag (AgNO3) for 48 h at 15°C and concentration of 0, 0.8, 4, or 20 μg/L. Immunocompetence was determined by hemocyte viability, phagocytosis, and cell cytotoxicity. Ag tissue loadings and levels of metallothioneins (MT), lipid peroxidation (LPO), and labile zinc (Zn) were also determined. Results revealed first that 20- and 80-nm nAg readily formed aggregates in freshwater. Ag was detected in soft tissues with each form of Ag with bioconcentration factors of 20, 9, and 7 for Ag(+), 20-nm nAg, and 80-nm nAg, respectively. Significant induction in phagocytosis and decreased cell cytotoxicity were observed. All forms of Ag were able to induce LPO in gills and digestive glands at concentrations below those from the initial fraction of dissolved Ag. The effects of nAg on MT levels in mussels were not discernible from those of dissolved Ag, but the 80-nm was 25-fold more potent than 20-nm nAg in inducing MT. Multivariate analysis revealed that the global responses of the 20- and 80-nm nAg were generally similar to those of dissolved Ag. Data also demonstrated that nAg are bioavailable for mussels where the immune system is a target during early exposure to nanoparticles.

ACS Style

F. Gagne; J. Auclair; M. Fortier; A. Bruneau; M. Fournier; P. Turcotte; Martin Pilote; C. Gagnon. Bioavailability and Immunotoxicity of Silver Nanoparticles to The Freshwater Mussel Elliptio complanata. Journal of Toxicology and Environmental Health, Part A 2013, 76, 767 -777.

AMA Style

F. Gagne, J. Auclair, M. Fortier, A. Bruneau, M. Fournier, P. Turcotte, Martin Pilote, C. Gagnon. Bioavailability and Immunotoxicity of Silver Nanoparticles to The Freshwater Mussel Elliptio complanata. Journal of Toxicology and Environmental Health, Part A. 2013; 76 (13):767-777.

Chicago/Turabian Style

F. Gagne; J. Auclair; M. Fortier; A. Bruneau; M. Fournier; P. Turcotte; Martin Pilote; C. Gagnon. 2013. "Bioavailability and Immunotoxicity of Silver Nanoparticles to The Freshwater Mussel Elliptio complanata." Journal of Toxicology and Environmental Health, Part A 76, no. 13: 767-777.

Journal article
Published: 31 May 2007 in Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology
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This study examined the toxic potential of a primary-treated municipal effluent, before and after ozonation, in freshwater mussels. Animals were exposed to various concentrations (0, 1, 3, 10 and 20% v/v) of a primary-treated effluent and also after a treatment with ozone at 10 mg/L in continuous flow-through mode for seven weeks. A suite of biomarkers was used to assess the potential toxic effects of various contaminants typically present in municipal wastewaters: heavy metal metabolism (metallothioneins and labile zinc), cytochrome P4501A1 and 3A4, glutathione S-transferase activities (biotransformation of organic compounds), lipid peroxidation and xanthine oxidoreductase (oxygen radical scavenging), DNA damage, mitochondrial electron transport activity at various temperatures and gonad lipid levels (cellular energy allocation) and aspartate transcarbamoylase and dihydrofolate reductase (gonad activity). On the one hand, some biomarkers, including metallothioneins, labile zinc, glutathione S-transferase, cytochrome P4503A4 activity, dehydrofolate reductase and aspartate transcarbamoylase, were readily decreased. In contrast, these biomarkers, cytochrome P4501A1, gill lipid peroxidation, DNA strand breaks in gills and digestive gland, mitochondrial electron transport at high and low temperatures (temperature-dependent activity) and total gonad lipids, were readily increased. In general, ozone treatment reduced adverse effects by either decreasing the intensity of the toxic responses or increasing the threshold concentration. For gill lipid peroxidation, however, intensity was greater at a higher threshold concentration. Ozone treatment eliminated the temperature sensitivity of the mitochondrial electron transport system, indicating a loss of interaction between temperature and urban pollution in terms of energy expenditure in mussels. Ozone treatment could significantly decrease either the toxic potency or intensity of urban pollutants at the expense of increased oxidative stress in gills of freshwater mussels.

ACS Style

F. Gagne; C. Andre; P. Cejka; C. Gagnon; C. Blaise. Toxicological effects of primary-treated urban wastewaters, before and after ozone treatment, on freshwater mussels (Elliptio complanata). Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology 2007, 145, 542 -552.

AMA Style

F. Gagne, C. Andre, P. Cejka, C. Gagnon, C. Blaise. Toxicological effects of primary-treated urban wastewaters, before and after ozone treatment, on freshwater mussels (Elliptio complanata). Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology. 2007; 145 (4):542-552.

Chicago/Turabian Style

F. Gagne; C. Andre; P. Cejka; C. Gagnon; C. Blaise. 2007. "Toxicological effects of primary-treated urban wastewaters, before and after ozone treatment, on freshwater mussels (Elliptio complanata)." Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology 145, no. 4: 542-552.