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Mehdi H, Morphet ME, Lau SC, Bragg LM, Servos MR, Parrott JL, Scott GR, Balshine S. Temperature modulates the impacts of wastewater exposure on the physiology and behaviour of fathead minnow. CHEMOSPHERE 2022; 294:133738. [PMID: 35085617 DOI: 10.1016/j.chemosphere.2022.133738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 01/10/2022] [Accepted: 01/22/2022] [Indexed: 06/14/2023]
Abstract
Municipal wastewater treatment plant (WWTP) effluent is a substantial source of pollution in aquatic habitats that can impact organisms across multiple levels of biological organization. Even though wastewater effluent is discharged continuously all year long, its impacts across seasons, specifically during winter, have largely been neglected in ecotoxicological research. Seasonal differences are of particular interest, as temperature-driven metabolic changes in aquatic organisms can significantly alter their ability to respond to chemical stressors. In this study, we examined the effects of multiple levels of wastewater effluent exposure (0, 25, or 50% treated effluent) on the physiological and behavioural responses of adult fathead minnow (Pimephales promelas) at temperatures simulating either summer (20 °C) or winter (4 °C) conditions. At 20 °C, wastewater exposure posed a metabolic cost to fish, demonstrated by higher standard metabolic rate and was associated with increased haematocrit and a reduction in boldness. In contrast, fish exposed to wastewater at 4 °C experienced no change in metabolic rate but performed fewer social interactions with their conspecifics. Taken together, our results demonstrate that wastewater exposure can lead to metabolic and behavioural disruptions, and such disruptions vary in magnitude and direction depending on temperature. Our findings highlight the importance of studying the interactions between stressors, while also underscoring the importance of research during colder periods of the year to broaden and deepen our understanding of the impacts of wastewater contamination in aquatic ecosystems.
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Affiliation(s)
- Hossein Mehdi
- Department of Psychology, Neuroscience & Behaviour, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada.
| | - Markelle E Morphet
- Department of Psychology, Neuroscience & Behaviour, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada.
| | - Samantha C Lau
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada.
| | - Leslie M Bragg
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.
| | - Mark R Servos
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.
| | - Joanne L Parrott
- Water Science and Technology Directorate, Environment and Climate Change Canada, 867 Lakeshore Road, Burlington, Ontario, L7S 1A1, Canada.
| | - Graham R Scott
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada.
| | - Sigal Balshine
- Department of Psychology, Neuroscience & Behaviour, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada.
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2
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A Multidisciplinary Approach Evaluating Soybean Meal-Induced Enteritis in Rainbow Trout Oncorhynchus mykiss. FISHES 2022. [DOI: 10.3390/fishes7010022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
This study evaluated a diverse range of markers of feeding stress to obtain a more precise assessment of the welfare of rainbow trout in relation to inadequate husbandry conditions. A feeding stress model based on dietary soybean meal was employed to identify suitable minimally invasive “classical” stress markers, together with molecular signatures. In a 56-day feeding experiment, rainbow trout were fed diets containing different levels of soybean meal. The impact of these different soybean meal diets on rainbow trout was assessed by water quality analyses, clinical health observations, classic growth and performance parameters, gut histopathology, blood-parameter measurements and multigene-expression profiling in RNA from whole blood. Soybean meal-induced enteritis was manifested phenotypically by an inflammatory reaction in the posterior section of the intestine and by diarrhoea in some trout. These inflammatory changes were associated with decreased supranuclear vacuolation. The haematocrit values and the levels of plasma cortisol and circulating lymphocytes in the blood were increased in trout that had consumed high amounts of SBM. Notably, the increased haematocrit depended significantly on the bodyweight of the individual trout. The transcript levels of certain genes (e.g., MAP3K1, LYG, NOD1, STAT1 and HSP90AB) emerged as potentially useful indicators in the blood of rainbow trout providing valuable information about inadequate nutrition. The expression-profiling findings provide a basis for improved, minimally invasive monitoring of feeding regimens in trout farming and may stimulate the development of practical detection devices for innovative aquaculture operations.
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Defo MA, Mercier L, Beauvais C, Brua RB, Tétreault G, Fontaine A, Couture P, Verreault J, Houde M. Time-dependent biological responses of juvenile yellow perch (Perca flavescens) exposed in situ to a major urban effluent. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 222:112483. [PMID: 34237640 DOI: 10.1016/j.ecoenv.2021.112483] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 06/25/2021] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
Municipal wastewater treatment plant (WWTP) effluents are significant sources of organic and inorganic pollutants to aquatic ecosystems. Several studies have shown that the health of aquatic organisms can be adversely impacted following exposure to these complex chemical mixtures. The objective of this study was to examine the effects of in situ exposure in the St. Lawrence River (QC, Canada) of juvenile yellow perch (Perca flavescens) to a major WWTP effluent. Perch were caged at a reference site in the St. Lawrence River and downstream of a WWTP effluent-influenced site for one, three, and six weeks. Fish kept in controlled laboratory setting were also examined at the beginning of the experiment to evaluate the potential effect of caging on fish. Liver metabolites and gill oxidative stress biomarkers as well as body condition of perch were investigated at four time points (zero, one, three, and six weeks). Nitrogen (δ15N) and carbon (δ13C) stable isotopes as well as tissue concentrations of halogenated flame retardants and trace metals were also analyzed. Results indicated that body condition of perch caged in the effluent increased after three and six weeks of exposure compared to that of reference fish. Perch caged at the WWTP effluent-influenced site also had higher muscle δ13C and slightly depleted muscle δ15N after three and six weeks of exposure, suggesting differences in sewage-derived nutrient assimilation between sites. Concentrations of Σ34 polybrominated diphenyl ether (PBDE) were 2-fold greater in perch exposed downstream of the WWTP compared to those caged at the reference site. Metal concentrations in kidney of perch after three weeks of exposure were significantly lower at the effluent-influenced site. Kidney concentrations of Cd, Cu, Se, As, Zn and Fe were, however, higher after six weeks of exposure, supporting that metal accumulation is time- and element-specific. The metabolomes of perch from the effluent-influenced and reference sites were similar, but were distinct from the laboratory control fish, suggesting a caging effect on fish. Seven liver metabolites (glucose, malate, fumarate, glutamate, creatinine, histamine, and oxypurinol) were significantly more abundant in perch from cages than in the laboratory control perch. The combination of metabolomics and physiological variables provides a powerful tool to improve our understanding of the mechanisms of action of complex environmental pollutant mixtures in wild fish.
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Affiliation(s)
- Michel A Defo
- Aquatic Contaminants Research Division, Environment and Climate Change Canada, 105 McGill St, Montreal, QC H2Y 2E7, Canada.
| | - Laurie Mercier
- Aquatic Contaminants Research Division, Environment and Climate Change Canada, 105 McGill St, Montreal, QC H2Y 2E7, Canada
| | - Conrad Beauvais
- Aquatic Contaminants Research Division, Environment and Climate Change Canada, 105 McGill St, Montreal, QC H2Y 2E7, Canada
| | - Robert B Brua
- Watershed Hydrology and Ecology Research Division, Environment and Climate Change Canada, 11 Innovation Blvd, Saskatoon, SK S7N 3H5, Canada
| | - Gerald Tétreault
- Aquatic Contaminants Research Division, Environment and Climate Change Canada, 867 Lakeshore Rd, Burlington, ON L7S 1A1, Canada
| | - Anthony Fontaine
- Institut national de la recherche scientifique (INRS), Centre Eau Terre Environnement, 490 de la Couronne, Québec, QC G1K 9A9, Canada
| | - Patrice Couture
- Institut national de la recherche scientifique (INRS), Centre Eau Terre Environnement, 490 de la Couronne, Québec, QC G1K 9A9, Canada
| | - Jonathan Verreault
- Centre de recherche en toxicologie de l'environnement (TOXEN), Département des sciences biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-ville, Montréal, QC H3C 3P8, Canada
| | - Magali Houde
- Aquatic Contaminants Research Division, Environment and Climate Change Canada, 105 McGill St, Montreal, QC H2Y 2E7, Canada
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4
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Defo MA, Gendron AD, Head J, Pilote M, Turcotte P, Marcogliese DJ, Houde M. Cumulative effects of cadmium and natural stressors (temperature and parasite infection) on molecular and biochemical responses of juvenile rainbow trout. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 217:105347. [PMID: 31715476 DOI: 10.1016/j.aquatox.2019.105347] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 05/06/2023]
Abstract
The simultaneous presence of natural and anthropogenic stressors in aquatic ecosystems can challenge the identification of factors causing decline in fish populations. These stressors include chemical mixtures and natural abiotic and biotic factors such as water temperature and parasitism. Effects of cumulative stressors may vary from antagonism to synergism at the organismal or population levels and may not be predicted from exposure to individual stressors. This study aimed to evaluate the combined effects of chronic exposure to cadmium (Cd) and elevated water temperature (23 °C) or parasite infection in juvenile rainbow trout (Oncorhynchus mykiss) using a multi-level biological approach, including RNA-sequencing. Fish were exposed to diet-borne Cd (6 μg Cd/g wet feed), individually and in combination with thermal (23 °C) or parasitic stressors, for 28 days. The parasite challenge consisted of a single exposure to glochidia (larvae) of the freshwater mussel (Strophitus undulatus), which encysts in fish gills, fins and skin. Results indicated lower fish length, weight, and relative growth rate in fish exposed to a higher water temperature (23 °C). Body condition and hepatosomatic index of trout were, however, higher in the 23 °C temperature treatment compared to the control fish kept at 15 °C. Exposure to thermal stress or parasitism did not influence tissue Cd bioaccumulation. More than 700 genes were differentially transcribed in fish exposed to the individual thermal stress treatment. However, neither Cd exposure nor parasite infection affected the number of differentially transcribed genes, compared to controls. The highest number of differentially transcribed genes (969 genes) was observed in trout exposed to combined Cd and high temperature stressors; these genes were mainly related to stress response, protein folding, calcium metabolism, bone growth, energy metabolism, and immune system; functions overlapped with responses found in fish solely exposed to higher water temperature. Only 40 genes were differentially transcribed when fish were exposed to Cd and glochidia and were related to the immune system, apoptosis process, energy metabolism and malignant tumor. These results suggest that dietary Cd may exacerbate the temperature stress and, to a lesser extent, parasitic infection stress on trout transcriptomic responses. Changes in the concentrations of liver ethoxyresorufin-o-deethylase, heat shock protein 70 and thiobarbituric acid reactive substances coupled to changes in the activities of cellular glutathione S-transferase and glucose-6-phosphate dehydrogenase were also observed at the cellular level. This study may help understand effects of freshwater fish exposure to cumulative stressors in a changing environment.
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Affiliation(s)
- Michel A Defo
- Environment and Climate Change Canada, 105 McGill Street, Montréal, QC, H2Y 2E7, Canada.
| | - Andrée D Gendron
- Environment and Climate Change Canada, 105 McGill Street, Montréal, QC, H2Y 2E7, Canada
| | - Jessica Head
- Department of Natural Resource Sciences, McGill University, 21111 Lakeshore Road, Ste-Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Martin Pilote
- Environment and Climate Change Canada, 105 McGill Street, Montréal, QC, H2Y 2E7, Canada
| | - Patrice Turcotte
- Environment and Climate Change Canada, 105 McGill Street, Montréal, QC, H2Y 2E7, Canada
| | - David J Marcogliese
- Environment and Climate Change Canada, 105 McGill Street, Montréal, QC, H2Y 2E7, Canada; St. Andrews Biological Station, 125 Marine Science Drive, St. Andrews, NB, E5B 0E4, Canada
| | - Magali Houde
- Environment and Climate Change Canada, 105 McGill Street, Montréal, QC, H2Y 2E7, Canada
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5
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Du SNN, Choi JA, McCallum ES, McLean AR, Borowiec BG, Balshine S, Scott GR. Metabolic implications of exposure to wastewater effluent in bluegill sunfish. Comp Biochem Physiol C Toxicol Pharmacol 2019; 224:108562. [PMID: 31254663 DOI: 10.1016/j.cbpc.2019.108562] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 06/18/2019] [Accepted: 06/25/2019] [Indexed: 02/01/2023]
Abstract
Effluent from wastewater treatment plants (WWTP) contains a complex mixture of contaminants and is a major worldwide source of aquatic pollution. We examined the effects of exposure to treated effluent from a municipal WWTP on the metabolic physiology of bluegill sunfish (Lepomis macrochirus). We studied fish that were wild-caught or experimentally caged (28 d) downstream of the WWTP, and compared them to fish that were caught or caged at clean reference sites. Survival was reduced in fish caged at the effluent-contaminated site compared to those caged at the reference site. Resting rates of O2 consumption (MO2) were higher in fish from the contaminated site, reflecting a metabolic cost of wastewater exposure. The increases in routine MO2 did not reduce aerobic scope (difference or quotient of maximal MO2 and resting MO2), suggesting that physiological compensations accompanied the metabolic costs of wastewater exposure. Fish exposed to wastewater also had larger hearts and livers. The activity of mitochondrial enzymes (cytochrome c oxidase, citrate synthase) per liver mass was unaltered across treatments, so the increased mass of this organ increased its cumulative oxidative capacity in the fish. Wastewater exposure also reduced glycogen content per liver mass. The effects of caging itself, based on comparisons between fish that were wild-caught or caged at clean sites, were generally subtle and not statistically significant. We conclude that exposure to wastewater effluent invokes a metabolic cost that leads to compensatory physiological adjustments that partially offset the detrimental metabolic impacts of exposure.
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Affiliation(s)
- Sherry N N Du
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Jasmine A Choi
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Erin S McCallum
- Department of Psychology, Neuroscience & Behaviour, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Adrienne R McLean
- Department of Psychology, Neuroscience & Behaviour, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Brittney G Borowiec
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Sigal Balshine
- Department of Psychology, Neuroscience & Behaviour, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Graham R Scott
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada.
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6
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Mehdi H, Dickson FH, Bragg LM, Servos MR, Craig PM. Impacts of wastewater treatment plant effluent on energetics and stress response of rainbow darter (Etheostoma caeruleum) in the Grand River watershed. Comp Biochem Physiol B Biochem Mol Biol 2018; 224:270-279. [DOI: 10.1016/j.cbpb.2017.11.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 11/13/2017] [Accepted: 11/20/2017] [Indexed: 01/26/2023]
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7
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Lazaro-Côté A, Sadoul B, Jackson LJ, Vijayan MM. Acute stress response of fathead minnows caged downstream of municipal wastewater treatment plants in the Bow River, Calgary. PLoS One 2018; 13:e0198177. [PMID: 29927929 PMCID: PMC6013188 DOI: 10.1371/journal.pone.0198177] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 05/15/2018] [Indexed: 11/20/2022] Open
Abstract
We examined whether exposure to municipal wastewater effluent (MWWE) compromised the stress performance of laboratory-reared fathead minnows (Pimephales promelas) in a field setting. Adult minnows were caged at two sites upstream and three sites downstream of wastewater treatments plants (WWTPs) discharging MWWE into the Bow River, Calgary, Alberta, Canada. At each site one group of fish was sampled after a 26 day exposure to MWWE, while another group was subjected to 1-min air exposure followed by 60-min confinement and then sampled. Fish morphometrics and proximate composition were measured, and whole-body cortisol, glucose and lactate levels assessed as markers of the stress response. The whole-body protein, glycogen and lipid content were higher at the site closest to a WWTP outfall relative to the other downstream and upstream sites. There were no significant differences in whole-body cortisol levels in minnows sampled at sites either upstream or downstream of WWTPs. Acute stressor exposure significantly elevated whole-body cortisol levels in all groups, and this response was not modified by the location of the sampling sites. The whole-body metabolite profile, including glucose and lactate levels, were significantly higher in fish caged immediately downstream from WWTP inputs relative to upstream sites. There was an acute-stressor-mediated increase in whole-body lactate, but not glucose, levels and this response was independent of sampling site. The results reveal that the capacity to evoke an acute stress response was not compromised in fathead minnows caged for 26 days downstream of WWTPs in the Bow River. However, there were changes in the whole-body proximate composition and metabolite levels immediately downstream from the WWTP outfall suggesting greater accumulation of energy stores in these fish. Taken together, our results suggest that environmental factors in addition to contaminants, including higher water temperature and nutrient availability, influence the impact of MWWEs on fish stress performance.
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Affiliation(s)
- Analisa Lazaro-Côté
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Bastien Sadoul
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Leland J. Jackson
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
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8
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Du SNN, McCallum ES, Vaseghi-Shanjani M, Choi JA, Warriner TR, Balshine S, Scott GR. Metabolic Costs of Exposure to Wastewater Effluent Lead to Compensatory Adjustments in Respiratory Physiology in Bluegill Sunfish. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:801-811. [PMID: 29211964 DOI: 10.1021/acs.est.7b03745] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Municipal wastewater effluent is a major source of aquatic pollution and has potential to impact cellular energy metabolism. However, it is poorly understood whether wastewater exposure impacts whole-animal metabolism and whether this can be accommodated with adjustments in respiratory physiology. We caged bluegill sunfish (Lepomis macrochirus) for 21 days at two sites downstream (either 50 or 830 m) from a wastewater treatment plant (WWTP). Survival was reduced in fish caged at both downstream sites compared to an uncontaminated reference site. Standard rates of O2 consumption increased in fish at contaminated sites, reflecting a metabolic cost of wastewater exposure. Several physiological adjustments accompanied this metabolic cost, including an expansion of the gill surface area available for gas exchange (reduced interlamellar cell mass), a decreased blood-O2 affinity (which likely facilitates O2 unloading at respiring tissues), increased respiratory capacities for oxidative phosphorylation in isolated liver mitochondria (supported by increased succinate dehydrogenase, but not citrate synthase, activity), and decreased mitochondrial emission of reactive oxygen species (ROS). We conclude that exposure to wastewater effluent invokes a metabolic cost that leads to compensatory respiratory improvements in O2 uptake, delivery, and utilization.
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Affiliation(s)
- Sherry N N Du
- Department of Biology, McMaster University , 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Erin S McCallum
- Department of Psychology, Neuroscience & Behaviour, McMaster University , 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Maryam Vaseghi-Shanjani
- Department of Biology, McMaster University , 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Jasmine A Choi
- Department of Biology, McMaster University , 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Theresa R Warriner
- Department of Psychology, Neuroscience & Behaviour, McMaster University , 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Sigal Balshine
- Department of Psychology, Neuroscience & Behaviour, McMaster University , 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Graham R Scott
- Department of Biology, McMaster University , 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
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9
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Wojnarowicz P, Yang W, Zhou H, Parker WJ, Helbing CC. Changes in hormone and stress-inducing activities of municipal wastewater in a conventional activated sludge wastewater treatment plant. WATER RESEARCH 2014; 66:265-272. [PMID: 25222330 DOI: 10.1016/j.watres.2014.08.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 08/11/2014] [Accepted: 08/12/2014] [Indexed: 06/03/2023]
Abstract
Conventional municipal wastewater treatment plants do not efficiently remove contaminants of emerging concern, and so are primary sources for contaminant release into the aquatic environment. Although these contaminants are present in effluents at ng-μg/L concentrations (i.e. microcontaminants), many compounds can act as endocrine disrupting compounds or stress-inducing agents at these levels. Chemical fate analyses indicate that additional levels of wastewater treatment reduce but do not always completely remove all microcontaminants. The removal of microcontaminants from wastewater does not necessarily correspond to a reduction in biological activity, as contaminant metabolites or byproducts may still be biologically active. To evaluate the efficacy of conventional municipal wastewater treatment plants to remove biological activity, we examined the performance of a full scale conventional activated sludge municipal wastewater treatment plant located in Guelph, Ontario, Canada. We assessed reductions in levels of conventional wastewater parameters and thyroid hormone disrupting and stress-inducing activities in wastewater at three phases along the treatment train using a C-fin assay. Wastewater treatment was effective at reducing total suspended solids, chemical and biochemical oxygen demand, and stress-inducing bioactivity. However, only minimal reduction was observed in thyroid hormone disrupting activities. The present study underscores the importance of examining multiple chemical and biological endpoints in evaluating and monitoring the effectiveness of wastewater treatment for removal of microcontaminants.
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Affiliation(s)
- Pola Wojnarowicz
- Department of Biochemistry & Microbiology, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
| | - Wenbo Yang
- School of Engineering, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Hongde Zhou
- School of Engineering, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Wayne J Parker
- Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Caren C Helbing
- Department of Biochemistry & Microbiology, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada.
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10
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Sandhu N, McGeer JC, Vijayan MM. Exposure to environmental levels of waterborne cadmium impacts corticosteroidogenic and metabolic capacities, and compromises secondary stressor performance in rainbow trout. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 146:20-27. [PMID: 24269906 DOI: 10.1016/j.aquatox.2013.10.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Revised: 10/02/2013] [Accepted: 10/08/2013] [Indexed: 06/02/2023]
Abstract
The physiological responses to waterborne cadmium exposure have been well documented; however, few studies have examined animal performances at low exposure concentrations of this metal. We tested the hypothesis that longer-term exposure to low levels of cadmium will compromise the steroidogenic and metabolic capacities, and reduce the cortisol response to a secondary stressor in fish. To test this, juvenile rainbow trout (Oncorhynchus mykiss) were exposed to 0 (control), 0.75 or 2.0 μg/L waterborne cadmium in a flow-through system and were sampled at 1, 7 and 28 d of exposure. There were only very slight disturbances in basal plasma cortisol, lactate or glucose levels in response to cadmium exposure over the 28 d period. Chronic cadmium exposure significantly affected key genes involved in corticosteroidogenesis, including melanocortin 2 receptor, steroidogenic acute regulatory protein and cytochrome P450 side chain cleavage enzyme. At 28 d, the high cadmium exposure group showed a significant drop in the glucocorticoid receptor and mineralocorticoid receptor protein expressions in the liver and brain, respectively. There were also perturbations in the metabolic capacities in the liver and gill of cadmium-exposed trout. Subjecting these fish to a secondary handling disturbance led to a significant attenuation of the stressor-induced plasma cortisol, glucose and lactate levels in the cadmium groups. Collectively, although trout appears to adjust to subchronic exposure to low levels of cadmium, it may be at the cost of impaired interrenal steroidogenic and tissue-specific metabolic capacities, leading to a compromised secondary stress performance in rainbow trout.
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Affiliation(s)
- Navdeep Sandhu
- Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - James C McGeer
- Department of Biology, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5, Canada
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11
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Dhanasiri AKS, Fernandes JMO, Kiron V. Liver transcriptome changes in zebrafish during acclimation to transport-associated stress. PLoS One 2013; 8:e65028. [PMID: 23762281 PMCID: PMC3677916 DOI: 10.1371/journal.pone.0065028] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 04/19/2013] [Indexed: 11/18/2022] Open
Abstract
Liver plays a key role during the stress acclimation, and liver transcriptome analysis of shipped zebrafish could reveal the molecular adjustments that occur in the organ. Transcriptional changes in liver were analyzed with a 44 K oligo array using total RNA from fish prior to transport and during a mock transport process--immediately after packing (0 h), at 48 and 72 h. Large numbers of genes related to a variety of biological processes and pathways were regulated, mainly during transport (at 48/72 h). Immediately after packing, transcripts of genes related to both gluconeogenesis and glycolysis were induced. During transport, induction of gluconeogenesis-linked genes and reduction of glycolysis-related genes may be supporting the increase in blood glucose levels. Inhibition of genes involved in fatty acid beta-oxidation may be pointing to the poor ability of fish to utilize energy from fatty acids, under transport conditions. Genes involved in some of the mechanisms that regulate body ammonia were also affected. Even though genes associated with certain transaminases were inhibited in liver, sustained glutamate deamination may have led to high ammonia accumulation in liver/body. Enhanced levels of gene transcripts in ubiquitination and MAPK signalling cascade and reduced levels of gene transcripts related to ROS generation via peroxisomal enzymes as well as xenobiotic metabolism may be signifying the importance of such cellular and tissue responses to maintain homeostasis. Furthermore, transcripts connected with stress and thyroid hormones were also regulated. Moreover, suppression of genes related to specific immune components may be denoting the deleterious impact of transport on fish health. Thus, this study has revealed the complex molecular adjustments that occur in zebrafish when they are transported.
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Affiliation(s)
| | | | - Viswanath Kiron
- Faculty of Biosciences and Aquaculture, University of Nordland, Bodø, Norway
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12
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Alderman SL, Vijayan MM. 11β-Hydroxysteroid dehydrogenase type 2 in zebrafish brain: a functional role in hypothalamus-pituitary-interrenal axis regulation. J Endocrinol 2012; 215:393-402. [PMID: 23042946 DOI: 10.1530/joe-12-0379] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The type 2, 11β-hydroxysteroid dehydrogenase (Hsd11b2) converts active glucocorticoids to their inactive derivatives (e.g. cortisol to cortisone). In most vertebrates, Hsd11b2 is essential for conferring aldosterone-specific actions in mineralocorticoid target tissues and for protecting glucocorticoid-sensitive tissues during stress. However, teleosts do not synthesize aldosterone, and the function of Hsd11b2 is poorly defined. The distribution of Hsd11b2 in nonmammalian brain is also largely unexplored. We tested the hypothesis that modulation of brain Hsd11b2 activity is involved in stressor-mediated cortisol regulation in zebrafish (Danio rerio). In adult zebrafish, the stress effect on Hsd11b2 expression in the brain was tested using acute air exposure followed by recovery over a 24-h period. hsd11b2 transcripts were found in nearly all peripheral tissues examined, and a spatial map of its mRNA abundance in unstressed zebrafish brain revealed extensive distribution. Stressor exposure increased the conversion of (3)H-cortisol to (3)H-cortisone indicating enhanced Hsd11b2 activity in zebrafish brain. Promoter analysis of zebrafish hsd11b2 gene revealed putative sites for cortisol-mediated transcriptional regulation of this gene. Furthermore, inhibition of Hsd11b2 activity by 18β-glycyrrhetinic acid resulted in elevated whole-body cortisol levels and preoptic area mRNA abundance of corticotropin-releasing factor and mineralocorticoid receptor. Taken together, our results underscore an important role for brain Hsd11b2 involvement in the negative feedback regulation of cortisol poststress in zebrafish.
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Affiliation(s)
- Sarah L Alderman
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
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