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Jarzynowska M, Saniewska D, Fudala K, Wilman B, Balazy P, Płońska P, Saniewski M. Mercury and methylmercury in birds and marine mammals inhabiting the coastal zone of the two King George Island's bays: Admiralty and King George Bay (maritime Antarctic). MARINE POLLUTION BULLETIN 2023; 193:115237. [PMID: 37421914 DOI: 10.1016/j.marpolbul.2023.115237] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/16/2023] [Accepted: 06/28/2023] [Indexed: 07/10/2023]
Abstract
The Antarctic is particularly sensitive to mercury (Hg) pollution and even low levels of Hg may cause significant damage in this fragile environment. The aim of this study was to investigate routes of mercury and methylmercury (MeHg) elimination by animals inhabiting the maritime Antarctic. The results showed that organisms at the highest trophic level (elephant seal) have the highest concentrations of THg and MeHg in both excrement and fur samples. Interspecies differences in mercury levels were observed in materials sourced from penguins of the genus Pysgocelis.13C and 15N values confirmed differences in the diets and foraging areas, which may affect Hg concentration in the tissues we analyzed. Time variations in THg and MeHg concentrations were observed in the excrement of the penguin species, which may be due to periods of fasting and intense feeding closely related to egg laying and moulting stages.
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Affiliation(s)
- Małgorzata Jarzynowska
- University of Gdansk, Faculty of Oceanography and Geography, Al. Piłsudskiego 46, 81-378 Gdynia, Poland
| | - Dominika Saniewska
- University of Gdansk, Faculty of Oceanography and Geography, Al. Piłsudskiego 46, 81-378 Gdynia, Poland.
| | - Katarzyna Fudala
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, Warsaw, Poland
| | - Bartłomiej Wilman
- Institute of Meteorology and Water Management - National Research Institute, Waszyngtona 42, 81-342 Gdynia, Poland
| | - Piotr Balazy
- Institute of Oceanology, Polish Academy of Sciences, Powstańców Warszawy 55, 81-712, Sopot, Poland
| | - Patrycja Płońska
- University of Gdansk, Faculty of Oceanography and Geography, Al. Piłsudskiego 46, 81-378 Gdynia, Poland
| | - Michał Saniewski
- Institute of Meteorology and Water Management - National Research Institute, Waszyngtona 42, 81-342 Gdynia, Poland
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2
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von Hellfeld R, Gade C, Koppel DJ, Walters WJ, Kho F, Hastings A. An approach to assess potential environmental mercury release, food web bioaccumulation, and human dietary methylmercury uptake from decommissioning offshore oil and gas infrastructure. JOURNAL OF HAZARDOUS MATERIALS 2023; 452:131298. [PMID: 36996541 DOI: 10.1016/j.jhazmat.2023.131298] [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: 11/23/2022] [Revised: 03/03/2023] [Accepted: 03/24/2023] [Indexed: 05/03/2023]
Abstract
Subsea pipelines carrying well fluids from hydrocarbon fields accumulate mercury. If the pipelines (after cleaning and flushing) are abandoned in situ, their degradation may release residual mercury into the environment. To justify pipeline abandonment, decommissioning plans include environmental risk assessments to determine the potential risk of environmental mercury. These risks are informed by environmental quality guideline values (EQGVs) governing concentrations in sediment or water above which mercury toxicity may occur. However, these guidelines may not consider e.g., the bioaccumulation potential of methylated mercury. Therefore, EQGVs may not protect humans from exposure if applied as the sole basis for risk assessments. This paper outlines a process to assess the EQGVs' protectiveness from mercury bioaccumulation, providing preliminary insights to questions including how to (1) determine pipeline threshold concentrations, (2) model marine mercury bioaccumulation, and (3) determine exceedance of the methylmercury tolerable weekly intake (TWI) for humans. The approach is demonstrated with a generic example using simplifications to describe mercury behaviour and a model food web. In this example, release scenarios equivalent to the EQGVs resulted in increased marine organism mercury tissue concentrations by 0-33 %, with human dietary methylmercury intake increasing 0-21 %. This suggests that existing guidelines may not be protective of biomagnification in all circumstances. The outlined approach could inform environmental risk assessments for asset-specific release scenarios but must be parameterised to reflect local environmental conditions when tailored to local factors.
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Affiliation(s)
- Rebecca von Hellfeld
- School of Biological Sciences, University of Aberdeen, School of Biological Sciences, Aberdeen, UK; National Decommissioning Centre, Ellon, UK.
| | - Christoph Gade
- School of Biological Sciences, University of Aberdeen, School of Biological Sciences, Aberdeen, UK; National Decommissioning Centre, Ellon, UK
| | - Darren J Koppel
- Curtin Oil and Gas Innovation Centre, Faculty of Science and Engineering, Curtin University, Perth, WA, Australia; Australian Institute of Marine Science, Perth, Australia
| | - William J Walters
- Ken and Mary Alice Lindquist Department of Nuclear Engineering, Pennsylvania State University, PA, USA
| | - Fenny Kho
- Curtin Oil and Gas Innovation Centre, Faculty of Science and Engineering, Curtin University, Perth, WA, Australia; Curtin Corrosion Centre, Curtin University, Perth, WA, Australia
| | - Astley Hastings
- School of Biological Sciences, University of Aberdeen, School of Biological Sciences, Aberdeen, UK; National Decommissioning Centre, Ellon, UK
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3
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Azevedo LF, Karpova N, Rocha BA, Barbosa Junior F, Gobe GC, Hornos Carneiro MF. Evidence on Neurotoxicity after Intrauterine and Childhood Exposure to Organomercurials. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:1070. [PMID: 36673825 PMCID: PMC9858833 DOI: 10.3390/ijerph20021070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/03/2023] [Accepted: 01/04/2023] [Indexed: 06/17/2023]
Abstract
Although the molecular mechanisms underlying methylmercury toxicity are not entirely understood, the observed neurotoxicity in early-life is attributed to the covalent binding of methylmercury to sulfhydryl (thiol) groups of proteins and other molecules being able to affect protein post-translational modifications from numerous molecular pathways, such as glutamate signaling, heat-shock chaperones and the antioxidant glutaredoxin/glutathione system. However, for other organomercurials such as ethylmercury or thimerosal, there is not much information available. Therefore, this review critically discusses current knowledge about organomercurials neurotoxicity-both methylmercury and ethylmercury-following intrauterine and childhood exposure, as well as the prospects and future needs for research in this area. Contrasting with the amount of epidemiological evidence available for methylmercury, there are only a few in vivo studies reporting neurotoxic outcomes and mechanisms of toxicity for ethylmercury or thimerosal. There is also a lack of studies on mechanistic approaches to better investigate the pathways involved in the potential neurotoxicity caused by both organomercurials. More impactful follow-up studies, especially following intrauterine and childhood exposure to ethylmercury, are necessary. Childhood vaccination is critically important for controlling infectious diseases; however, the safety of mercury-containing thimerosal and, notably, its effectiveness as preservative in vaccines are still under debate regarding its potential dose-response effects to the central nervous system.
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Affiliation(s)
- Lara Ferreira Azevedo
- Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-903, SP, Brazil
| | - Nina Karpova
- Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-903, SP, Brazil
| | - Bruno Alves Rocha
- Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-903, SP, Brazil
| | - Fernando Barbosa Junior
- Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-903, SP, Brazil
| | - Glenda Carolyn Gobe
- Kidney Disease Research Group, School of Medicine, Translational Research Institute, University of Queensland, 37 Kent Street, Woolloongabba, QLD 4102, Australia
| | - Maria Fernanda Hornos Carneiro
- Department of Pharmacy, Faculty of Chemistry and Pharmacy, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
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4
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Boutet V, Dominique M, Eccles KM, Branigan M, Dyck M, van Coeverden de Groot P, Lougheed SC, Rutter A, Langlois VS. An exploratory spatial contaminant assessment for polar bear (Ursus maritimus) liver, fat, and muscle from northern Canada. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 316:120663. [PMID: 36395907 PMCID: PMC10163957 DOI: 10.1016/j.envpol.2022.120663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 11/11/2022] [Accepted: 11/12/2022] [Indexed: 05/08/2023]
Abstract
Since the industrial era, chemicals have been ubiquitous in worldwide ecosystems. Despite the discontinued release of highly toxic persistent organic pollutants (POPs) in the environment, the levels of some POPs are still being measured in the Canadian Arctic. These contaminants are of great concern due to their persistence, toxicity, and levels of bioaccumulation in food chains. Animals occupying top trophic positions in the Canadian Arctic, particularly polar bears, are exposed to these contaminants mainly through their diet. Our study investigated the levels of 30 metals (including total and methyl mercury) alkaline and alkaline earth metals, 15 polycyclic aromatic compounds and their alkyl congeners (PACs), 6 chlordanes (CHLs), and 20 polychlorinated biphenyls (PCBs), in 49 polar bears from the Canadian Arctic. Contaminant burden was measured in liver, muscle, and fat in bears of different sex, age, and locations. A principal component analysis did not distinguish differences between age and sex profiles for most contaminants. However, the concentrations measured and their distribution in the tissues confirm findings observed in past studies. This study highlights the importance of continual monitoring of polar bear health (e.g., newly detected PACs were measured within this study) and evaluating those impacts for the next generations of polar bears.
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Affiliation(s)
- V Boutet
- Institut national de la recherche scientifique (INRS), Québec, Canada
| | - M Dominique
- Institut national de la recherche scientifique (INRS), Québec, Canada
| | - K M Eccles
- National Institute of Environmental Health Science, Division of the National Toxicology Program, Durham, USA
| | - M Branigan
- Government of the Northwest Territories, Canada
| | - M Dyck
- Government of Nunavut, Department of Environment, Igloolik, NU, Canada
| | | | - S C Lougheed
- Biology Department, Queen's University, Kingston, ON, Canada
| | - A Rutter
- School of Environmental Studies, Queen's University, Kingston, ON, Canada
| | - V S Langlois
- Institut national de la recherche scientifique (INRS), Québec, Canada.
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5
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Taylor S, Terkildsen M, McQuilty R, Lee D, Wing-Simpson A, Gray R. Non-essential heavy metals and protective effects of selenium against mercury toxicity in endangered Australian sea lion (Neophoca cinerea) pups with hookworm disease. ENVIRONMENT INTERNATIONAL 2022; 169:107521. [PMID: 36148712 DOI: 10.1016/j.envint.2022.107521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 08/06/2022] [Accepted: 09/11/2022] [Indexed: 06/16/2023]
Abstract
The endangered Australian sea lion, Neophoca cinerea, faces ongoing population decline. Identification of key threats to N. cinerea population recovery, including disease and pollutants, is an objective of the species' recovery plan. Previous studies have identified Uncinaria sanguinis, an intestinal nematode, as a significant cause of disease and mortality in N. cinerea pups. Given the impact of heavy metals on the immune response, investigation of these pollutants is critical. To this end, the concentrations of arsenic (As), total mercury (Hg), cadmium (Cd), chromium (Cr), lead (Pb) and selenium (Se) were determined in blood collected from N. cinerea pups sampled during the 2017/18, 2019 and 2020/21 breeding seasons at Seal Bay Conservation Park, South Australia. Significant differences (p < 0.05) in Hg, As, Cr, and Se concentrations and molar ratio of Se:Hg were seen between breeding seasons. Pup age, maternal parity and inter-individual foraging behaviour were considered factors driving these differences. The concentrations of Hg (357, 198 and 241 µg/L) and As (225, 834 and 608 µg/L) were high in 2017/18, 2019 and 2020/21 respectively with Hg concentrations in the blood of N. cinerea pups above toxicological thresholds reported for marine mammals. The concentration of Se (1332, 647, 763 µg/L) and molar ratio of Se:Hg (9.47, 7.98 and 6.82) were low compared to other pinniped pups, indicating potential vulnerability of pups to the toxic effects of Hg. Significant (p < 0.05) negative associations for Pb and Cd with several red blood cell parameters suggest they could be exacerbating the anaemia caused by hookworm disease. Temporal (age-related) changes in element concentrations were also seen, such that pup age needs to be considered when interpreting bioaccumulation patterns. Further investigation of the role of elevated heavy metal concentrations on N. cinerea pup health, disease and development is recommended, particularly with respect to immunological impacts.
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Affiliation(s)
- Shannon Taylor
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camperdown, NSW 2006, Australia
| | | | - Robert McQuilty
- Department of Chemical Pathology, Royal Prince Alfred Hospital, Camperdown, Sydney 2050, Australia
| | - David Lee
- Department of Chemical Pathology, Royal Prince Alfred Hospital, Camperdown, Sydney 2050, Australia
| | - Aileen Wing-Simpson
- Department of Chemical Pathology, Royal Prince Alfred Hospital, Camperdown, Sydney 2050, Australia
| | - Rachael Gray
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camperdown, NSW 2006, Australia.
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6
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Kho F, Koppel DJ, von Hellfeld R, Hastings A, Gissi F, Cresswell T, Higgins S. Current understanding of the ecological risk of mercury from subsea oil and gas infrastructure to marine ecosystems. JOURNAL OF HAZARDOUS MATERIALS 2022; 438:129348. [PMID: 35797785 DOI: 10.1016/j.jhazmat.2022.129348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/31/2022] [Accepted: 06/08/2022] [Indexed: 06/15/2023]
Abstract
Many oil and gas fields are nearing production cessation and will require decommissioning, with the preferred method being complete infrastructure removal in most jurisdictions. However, decommissioning in situ, leaving some disused components in place, is an option that may be agreed to by the regulators and reservoir titleholders in some circumstances. To understand this option's viability, the environmental impacts and risks of any residual contaminants assessed. Mercury, a contaminant of concern, is naturally present in hydrocarbon reservoirs, may contaminate offshore processing and transmission infrastructure, and can biomagnify in marine ecosystems. Mercury's impact is dependent on its speciation, concentration, and the exposure duration. However, research characterising and quantifying the amount of mercury in offshore infrastructure and the efficacy of decontamination is limited. This review describes the formation of mercury-contaminated products within oil and gas infrastructure, expected exposure pathways after environmental release, possible impacts, and key research gaps regarding the ecological risk of in situ decommissioned contaminated infrastructure. Suggestions are made to overcome these gaps, improving the in situ mercury quantification in infrastructure, understanding environmental controls on, and forecasting of, mercury methylation and bioaccumulation, and the cumulative impacts of multiple stressors within decommissioned infrastructures.
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Affiliation(s)
- Fenny Kho
- Faculty of Science and Engineering, Curtin University, Perth, WA, Australia; Curtin Corrosion Centre, Curtin University, Perth, WA, Australia
| | - Darren J Koppel
- Faculty of Science and Engineering, Curtin University, Perth, WA, Australia; Australian Institute of Marine Science, Perth, WA, Australia
| | - Rebecca von Hellfeld
- National Decommissioning Centre, University of Aberdeen, Aberdeen, Scotland, UK.
| | - Astley Hastings
- National Decommissioning Centre, University of Aberdeen, Aberdeen, Scotland, UK
| | - Francesca Gissi
- Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW, Australia
| | - Tom Cresswell
- Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW, Australia
| | - Stuart Higgins
- Faculty of Science and Engineering, Curtin University, Perth, WA, Australia
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7
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Kalisinska E, Lanocha-Arendarczyk N, Podlasinska J. Current and historical nephric and hepatic mercury concentrations in terrestrial mammals in Poland and other European countries. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 775:145808. [PMID: 33621879 DOI: 10.1016/j.scitotenv.2021.145808] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 02/06/2021] [Accepted: 02/07/2021] [Indexed: 06/12/2023]
Abstract
The long-term anthropogenic release of mercury (Hg) into the environment has led to contamination of the biosphere, with all forms of Hg showing toxic effects and the ability to accumulate in organisms. Since the 1970s, efforts have been made in Western Europe to reduce Hg emissions and for the economic use of Hg, leading to a reduction in Hg exposure to humans and entire ecosystems. The purpose of this research was to present the total mercury (THg) burden in three mustelids (the piscivorous Eurasian otter and American mink, and the invertebrativorous European badger) inhabiting north-western Poland (mostly floodplains) and other European countries (literature data). Moreover, we wanted to investigate whether reductions in the environmental Hg burden in Europe have resulted in reductions in liver and kidney levels in wild terrestrial mammals (Eurasian otter, wild boar, red deer, roe deer, cervids, leporids, rodents, and ecotrophic groups: piscivorous mustelids, non-mustelids whose diets include aquatic prey, canids and other carnivores, omnivores, herbivores), between samples collected before and after 2000. We revealed significantly higher nephric THg levels in roadkilled than in trapped American minks. As roadkilled piscivorous mustelids from the same floodplain had similar hepatic and nephric THg concentrations, we suggest that the European research on Hg ecotoxicology should more often use alien American mink instead of the protected Eurasian otter. Badgers inhabiting Polish and other European floodplains bioaccumulated higher amounts of THg than those from other areas, and as such, may be recommended as bioindicator of mercury soil contamination. Our analysis of abundant data on mammalian hepatic and nephric THg concentrations (excluding non-piscivores mustelids) showed that in 12 of 21 cases, Hg concentrations had dropped significantly since 2000. This data signals a reduction in Hg contamination in terrestrial mammals, such as the Eurasian otter, and may be reason for cautious optimism.
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Affiliation(s)
- Elżbieta Kalisinska
- Department of Biology and Medical Parasitology, Pomeranian Medical University in Szczecin, Powstancow Wielkopolskich 72, 70-111 Szczecin, Poland.
| | - Natalia Lanocha-Arendarczyk
- Department of Biology and Medical Parasitology, Pomeranian Medical University in Szczecin, Powstancow Wielkopolskich 72, 70-111 Szczecin, Poland
| | - Joanna Podlasinska
- Department of Environmental Management, West Pomeranian University of Technology, Szczecin, Poland
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8
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Haskins DL, Brown MK, Qin C, Xu X, Pilgrim MA, Tuberville TD. Multi-decadal trends in mercury and methylmercury concentrations in the brown watersnake (Nerodia taxispilota). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 276:116722. [PMID: 33640654 DOI: 10.1016/j.envpol.2021.116722] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/19/2021] [Accepted: 02/08/2021] [Indexed: 06/12/2023]
Abstract
Mercury (Hg) is an environmental contaminant that poses a threat to aquatic systems globally. Temporal evaluations of Hg contamination have increased in recent years, with studies focusing on how anthropogenic activities impact Hg bioavailability in a variety of aquatic systems. While it is common for these studies and ecological risk assessments to evaluate Hg bioaccumulation and effects in wildlife, there is a paucity of information regarding Hg dynamics in reptiles. The goal of this study was to investigate temporal patterns in total mercury (THg) and methylmercury (MeHg) concentrations across a 36-year period, as well as evaluate relationships among and between destructive (kidney, liver, muscle) and non-destructive (blood, tail) tissue types in a common watersnake species. To accomplish this, we measured THg and MeHg concentrations in multiple tissues from brown watersnakes (Nerodia taxispilota) collected from Steel Creek on the Savannah River Site (SRS; Aiken, SC, USA) from two time periods (1983-1986 and 2019). We found significant and positive relationships between tail tips and destructive tissues. In both time periods, THg concentrations varied significantly by tissue type, and destructive tissues exhibited higher but predictable THg values relative to tail tissue. Methylmercury concentrations did not differ among tissues from the 1980s but was significantly higher in muscle compared to other tissues from snakes collected in 2019. Percent MeHg of THg in N. taxispilota tissues mirrored patterns reported in other reptiles, although the range of % MeHg in liver and kidney differed between time periods. Both THg and MeHg concentrations in N. taxispilota declined significantly from the 1980s to 2019, with average values 1.6 to 4-fold lower in contemporary samples. Overall, our data add further evidence to the utility of watersnakes to monitor Hg pollution in aquatic environments and suggest attenuation of this contaminant in watersnakes in our study system.
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Affiliation(s)
- David L Haskins
- Interdisciplinary Toxicology Program, University of Georgia, Athens, GA, 30605, USA; Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30605, USA; Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, 29802, USA.
| | - M Kyle Brown
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30605, USA; Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, 29802, USA
| | - Chongyang Qin
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, 29802, USA
| | - Xiaoyu Xu
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, 29802, USA
| | - Melissa A Pilgrim
- Division of Natural Sciences and Engineering, University of South Carolina Upstate, Spartanburg, SC, 29303, USA
| | - Tracey D Tuberville
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, 29802, USA
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9
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Liu T, Gao Q, Yang B, Yin C, Chang J, Qian H, Xing G, Wang S, Li F, Zhang Y, Chen D, Cai J, Shi H, Aschner M, Appiah-Kubi K, He D, Lu R. Differential susceptibility of PC12 and BRL cells and the regulatory role of HIF-1α signaling pathway in response to acute methylmercury exposure under normoxia. Toxicol Lett 2020; 331:82-91. [PMID: 32461003 PMCID: PMC7366344 DOI: 10.1016/j.toxlet.2020.05.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 05/15/2020] [Accepted: 05/18/2020] [Indexed: 12/24/2022]
Abstract
Hypoxia-inducible factor 1 (HIF-1) is a critical nuclear transcription factor for adaptation to hypoxia; its regulatable subunit, HIF-1α, is a cytoprotective regulatory factor. We examined the effects of methylmercury (MeHg) in rat adrenal pheochromocytoma (PC12) cells and the rat hepatocyte cell line BRL. MeHg treatment led to time- and concentration-dependent toxicity in both lines with statistically significant cytotoxic effects at 5 μM and 10 μM in PC12 and BRL, respectively, at 0.5 h. HIF-1α protein levels were significantly decreased at 2.5 (PC12) and 5 (BRL) μM MeHg. Furthermore, MeHg reduced the protein levels of HIF-1α and its target genes (glucose transporter-1, vascular endothelial growth factor-A and erythropoietin). Overexpression of HIF-1α significantly attenuated MeHg-induced toxicity in both cell types. Notably, cobalt chloride, a pharmacological inducer of HIF-1α, significantly attenuated MeHg-induced toxicity in BRL but not PC12. In both cell lines, an inhibitor of prolyl hydroxylase, 3, 4-dihydroxybenzoic acid, and the proteasome inhibitor carbobenzoxy-L-leucyl-L-leucyl-L-leucinal(MG132), antagonized MeHg toxicity, while 2-methoxyestradiol, a HIF-1α inhibitor, significantly increased it. These data establish that: (a) neuron-like PC12 cells are more sensitive to MeHg than non-neuronal BRL cells; (b) HIF-1α plays a similar role in MeHg-induced toxicity in both cell lines; and (c) upregulation of HIF-1α offers general cytoprotection against MeHg toxicity in PC12 and BRL cell lines.
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Affiliation(s)
- Tingting Liu
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Qianqian Gao
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Bobo Yang
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Changsheng Yin
- Institute of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, China; Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Jie Chang
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Hai Qian
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Guangwei Xing
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Suhua Wang
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Fang Li
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Yubin Zhang
- Department of Occupational Health and Toxicology, School of Public Health, Fudan University, Shanghai 200032, China
| | - Da Chen
- School of Environment, Jinan University, Guangzhou, Guangdong 510632, China
| | - Jiyang Cai
- Department of Physiology, College of Medicine, University of Oklahoma Health Science Center, Lindsay, Oklahoma City, OK 73104, USA
| | - Haifeng Shi
- Institute of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Kwaku Appiah-Kubi
- Department of Applied Biology, C. K. Tedam University of Technology and Applied Sciences, Navrongo, UK-0215-5321, Ghana
| | - Dawei He
- Center for Experimental Research, Kunshan Hospital Affiliated to Jiangsu University, Kunshan, Jiangsu 215130, China
| | - Rongzhu Lu
- Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China; Center for Experimental Research, Kunshan Hospital Affiliated to Jiangsu University, Kunshan, Jiangsu 215130, China.
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10
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López-Berenguer G, Peñalver J, Martínez-López E. A critical review about neurotoxic effects in marine mammals of mercury and other trace elements. CHEMOSPHERE 2020; 246:125688. [PMID: 31896013 DOI: 10.1016/j.chemosphere.2019.125688] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/16/2019] [Accepted: 12/16/2019] [Indexed: 05/26/2023]
Abstract
Marine mammals are more exposed to mercury (Hg) than any others animals in the world. As many trace elements, Hg it is able to impair the brain function, which could be a cause of population decline. Nevertheless, these issues have been scarcely studied because of the technical and ethical difficulties. We conducted a systematic review about marine mammals' brain exposition to Hg and other trace elements, and their neurotoxic effects. Information was scarce and the lack of standardization of nomenclature of brain structures, sample collecting and results presentation made it difficult to obtain conclusions. Hg was the most studied metal and toothed whales the most studied group. Despite being its target organ, brain accumulates lesser concentrations of Hg than other tissues as liver. We found a significant positive correlation between both organs' burden (rho = 0.956 for cetaceans; rho = 0.756 for pinnipeds). Reported Hg values in brain of cetaceans (median 3.00 ppm ww) surpassed by one or two orders of magnitude those values found in other species as pinnipeds (median 0.33 ppm ww) or polar bears (median 0.07 ppm ww). Such values exceeded neurotoxicity thresholds. Although marine mammals ingest mostly the organic and more toxic form MeHg, different fractions of inorganic mercury can appear in brain, which could suggest some detoxification mechanisms. Other suggested mechanisms include Se-Hg interaction and liver sequestration. Although other elements are subjected to a rigid homeostatic control, appear in low concentrations or do not exert an important neurotoxic effect, they should be more studied to elucidate their neurotoxicity potential.
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Affiliation(s)
- G López-Berenguer
- Area of Toxicology, Department of Health Sciences, Faculty of Veterinary Medicine, University of Murcia, 30100, Murcia, Spain
| | - J Peñalver
- Area of Toxicology, Department of Health Sciences, Faculty of Veterinary Medicine, University of Murcia, 30100, Murcia, Spain; Fisheries and Aquaculture Service (CARM), 30100, Murcia, Spain
| | - E Martínez-López
- Area of Toxicology, Department of Health Sciences, Faculty of Veterinary Medicine, University of Murcia, 30100, Murcia, Spain; Toxicology and Risk Assessment Group, Biomedical Research Institute of Murcia (IMIB-Arrixaca), University of Murcia, 30100, Murcia, Spain.
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11
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Ma L, Wang W, Xie MW, Wang WX, Evans RD. Using Zn Isotopic Signatures for Source Identification in a Contaminated Estuary of Southern China. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:5140-5149. [PMID: 32202770 DOI: 10.1021/acs.est.9b05955] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Zinc isotope ratios in water and suspended particles (SP) were measured in the Pearl River Estuary (PRE), China. Site-to-site δ66Zn values in water varied by approximately 1.3‰ (i.e., -0.66‰ to 0.65‰ relative to IRMM-3702 in August 2017). There were larger variations in δ66Zn values in water collected from the east shore (i.e., -0.66‰ to 0.37‰) of the PRE close to industrialized areas, in comparison to those from the western shore (i.e., -0.23‰ to 0.13‰), indicating that the PRE was influenced by different Zn sources. The variations in δ66Zn values in water from estuarine locations were much larger than those collected from river mouths. Similarly, larger variations in δ66Zn values were observed in suspended particles (i.e., -1.45‰ to 0.63‰) relative to the water. Zinc isotopic differences (i.e., Δ66Zn‰) between particles and water were significantly (p < 0.05) and linearly correlated with Zn concentrations in particles between 0.8 and 10 μm in size at most of the estuary stations, suggesting that Zn partitioning between dissolved and particulate phases influences the observed differences in Zn isotope ratios. A significant (p < 0.0001) linear correlation between the predicted δ66Zn values (using variations in water salinities) vs observed δ66Zn values indicates that Zn isotope ratios in water in the PRE can be useful for predicting the mixing processes in the water.
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Affiliation(s)
- Lan Ma
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, Ontario, Canada K9L 0G2
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, People's Republic of China
| | - Wei Wang
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, Ontario, Canada K9L 0G2
| | - Min-Wei Xie
- College of Environment and Ecology, Xiamen University, Fujian 361102, People's Republic of China
| | - Wen-Xiong Wang
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, People's Republic of China
| | - R Douglas Evans
- Water Quality Centre, Trent University, 1600 West Bank Drive, Peterborough, Ontario, Canada K9L 0G2
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12
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Chételat J, Ackerman JT, Eagles-Smith CA, Hebert CE. Methylmercury exposure in wildlife: A review of the ecological and physiological processes affecting contaminant concentrations and their interpretation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 711:135117. [PMID: 31831233 DOI: 10.1016/j.scitotenv.2019.135117] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/15/2019] [Accepted: 10/21/2019] [Indexed: 05/12/2023]
Abstract
Exposure to methylmercury (MeHg) can result in detrimental health effects in wildlife. With advances in ecological indicators and analytical techniques for measurement of MeHg in a variety of tissues, numerous processes have been identified that can influence MeHg concentrations in wildlife. This review presents a synthesis of theoretical principals and applied information for measuring MeHg exposure and interpreting MeHg concentrations in wildlife. Mercury concentrations in wildlife are the net result of ecological processes influencing dietary exposure combined with physiological processes that regulate assimilation, transformation, and elimination. Therefore, consideration of both physiological and ecological processes should be integrated when formulating biomonitoring strategies. Ecological indicators, particularly stable isotopes of carbon, nitrogen, and sulfur, compound-specific stable isotopes, and fatty acids, can be effective tools to evaluate dietary MeHg exposure. Animal species differ in their physiological capacity for MeHg elimination, and animal tissues can be inert or physiologically active, act as sites of storage, transformation, or excretion of MeHg, and vary in the timing of MeHg exposure they represent. Biological influences such as age, sex, maternal transfer, and growth or fasting are also relevant for interpretation of tissue MeHg concentrations. Wildlife tissues that represent current or near-term bioaccumulation and in which MeHg is the predominant mercury species (such as blood and eggs) are most effective for biomonitoring ecosystems and understanding landscape drivers of MeHg exposure. Further research is suggested to critically evaluate the use of keratinized external tissues to measure MeHg bioaccumulation, particularly for less-well studied wildlife such as reptiles and terrestrial mammals. Suggested methods are provided to effectively use wildlife for quantifying patterns and drivers of MeHg bioaccumulation over time and space, as well as for assessing the potential risk and toxicological effects of MeHg on wildlife.
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Affiliation(s)
- John Chételat
- Environment and Climate Change Canada, National Wildlife Research Centre, 1125 Colonel By Drive, Ottawa, ON K1A 0H3, Canada.
| | - Joshua T Ackerman
- U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive, Suite D, Dixon, CA 95620, United States
| | - Collin A Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, Oregon, 97331, United States
| | - Craig E Hebert
- Environment and Climate Change Canada, National Wildlife Research Centre, 1125 Colonel By Drive, Ottawa, ON K1A 0H3, Canada
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13
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Kershaw JL, Hall AJ. Mercury in cetaceans: Exposure, bioaccumulation and toxicity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 694:133683. [PMID: 31394330 DOI: 10.1016/j.scitotenv.2019.133683] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 07/29/2019] [Accepted: 07/29/2019] [Indexed: 05/27/2023]
Abstract
The fate and transportation of mercury in the marine environment are driven by a combination of anthropogenic atmospheric and aquatic sources, as well as natural geological inputs. Mercury biomagnifies up the food chain, resulting in the bioaccumulation of toxic concentrations in higher trophic organisms even when concentrations in their habitat remain below the threshold level for direct toxicity. As a result, mercury exposure has been recognised as a health concern for both humans and top marine predators, including cetaceans. There appears to be no overall trend in the global measured concentrations reported in cetaceans between 1975 and 2010, although differences between areas show that the highest concentrations in recent decades have been measured in the tissues of Mediterranean odontocetes. There is increasing concern for the impacts of mercury on the Arctic marine ecosystem with changes in water temperatures, ocean currents, and prey availability, all predicted to affect exposure. The accumulation of mercury in various tissues has been linked to renal and hepatic damage as well as reported neurotoxic, genotoxic, and immunotoxic effects. These effects have been documented through studies on stranded and by-caught cetaceans as well as in vitro cell culture experiments. Demethylation of methylmercury and protection by selenium have been suggested as possible mercury detoxification mechanisms in cetaceans that may explain the very high concentrations measured in tissues of some species with no apparent acute toxicity. Thus, the ratio of selenium to mercury is of importance when aiming to determine the impact of the contaminant load at an individual level. The long-term population level effects of mercury exposure are unknown, and continued monitoring of odontocete populations in particular is advised in order to predict the consequences of mercury uptake on marine food chains in the future.
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Affiliation(s)
- Joanna L Kershaw
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews KY16 8LB, UK.
| | - Ailsa J Hall
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews KY16 8LB, UK
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14
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High-precision isotopic analysis sheds new light on mercury metabolism in long-finned pilot whales (Globicephala melas). Sci Rep 2019; 9:7262. [PMID: 31086275 PMCID: PMC6513992 DOI: 10.1038/s41598-019-43825-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 04/29/2019] [Indexed: 12/14/2022] Open
Abstract
Whales accumulate mercury (Hg), but do not seem to show immediate evidence of toxic effects. Analysis of different tissues (liver, kidney, muscle) and biofluids (blood, milk) from a pod of stranded long-finned pilot whales (Globicephala melas) showed accumulation of Hg as a function of age, with a significant decrease in the MeHg fraction. Isotopic analysis revealed remarkable differences between juvenile and adult whales. During the first period of life, Hg in the liver became isotopically lighter (δ202Hg decreased) with a strongly decreasing methylmercury (MeHg) fraction. We suggest this is due to preferential demethylation of MeHg with the lighter Hg isotopes and transport of MeHg to less sensitive organs, such as the muscles. Also changes in diet, with high MeHg intake in utero and during lactation, followed by increasing consumption of solid food contribute to this behavior. Interestingly, this trend in δ202Hg is reversed for livers of adult whales (increasing δ202Hg value), accompanied by a progressive decrease of δ202Hg in muscle at older ages. These total Hg (THg) isotopic trends suggest changes in the Hg metabolism of the long-finned pilot whales, development of (a) detoxification mechanism(s) (e.g., though the formation of HgSe particles), and Hg redistribution across the different organs.
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15
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Ewald JD, Kirk JL, Li M, Sunderland EM. Organ-specific differences in mercury speciation and accumulation across ringed seal (Phoca hispida) life stages. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 650:2013-2020. [PMID: 30290344 DOI: 10.1016/j.scitotenv.2018.09.299] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 09/17/2018] [Accepted: 09/22/2018] [Indexed: 05/12/2023]
Abstract
Methylmercury (MeHg) is a central nervous system toxicant and exposures can adversely affect the health of marine mammals. Mercuric selenide (HgSe) in marine mammal tissues is hypothesized to result from a protective detoxification mechanism, but toxicokinetic processes contributing to its formation are poorly understood. Here, new data is reported on speciated Hg concentrations in multiple organs of n = 56 ringed seals (Phoca hispida) from Labrador, Canada, and compare concentrations to previously published data from Greenland seals. A higher proportion of Hg is found to accumulate in the kidney of young-of-the-year (YOY) ringed seals compared to adults. A toxicokinetic model for Hg species is developed and evaluated to better understand factors affecting variability in Hg concentrations among organs and across life stages. Prior work postulated that HgSe formation only occurs in the liver of mature seals, but model results suggest HgSe formation occurs across all life stages. Higher proportions of HgSe in mature seal livers compared to YOY seals likely results from the slow accumulation and elimination of HgSe (total body half-life = 500 days) compared to other Hg species. HgSe formation in the liver reduces modeled blood concentrations of MeHg by only 6%. Thus, HgSe formation may not substantially reduce MeHg transport across the blood-brain barrier of ringed seals, leaving them susceptible to the neurotoxic effects of MeHg exposure.
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Affiliation(s)
- Jessica D Ewald
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, United States; Faculty of Agricultural and Environmental Sciences, Macdonald Campus, McGill University Ste-Anne-de-Bellevue, Quebec H9X 3V9, Canada.
| | - Jane L Kirk
- Environment and Climate Change Canada, Canada Centre for Inland Waters, Burlington, Ontario L7S 1A1, Canada
| | - Miling Li
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, United States; Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA 02115, United States
| | - Elsie M Sunderland
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, United States; Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA 02115, United States
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16
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Ma L, Evans RD, Wang W, Georg RB. In vivo fractionation of mercury isotopes in tissues of a mammalian carnivore (Neovison vison). THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 627:1228-1233. [PMID: 30857087 DOI: 10.1016/j.scitotenv.2018.01.296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 01/13/2018] [Accepted: 01/28/2018] [Indexed: 06/09/2023]
Abstract
The use of isotope ratios to trace Hg contamination sources in environmental compartments is now generally accepted. However, for biota and especially for mammals, it is still unknown if and/or how Hg isotopes fractionate in vivo and which tissue is most representative of the source(s) of contamination. We measured fractionation of Hg in mink (Neovison vison) tissues (fur, brain, blood, liver, kidney) collected during a controlled feeding experiment where captive mink were fed differing amounts of methylmercury. There was no significant effect of dietary MeHg concentrations on Hg fractionation in most tissues. Net fractionation of Hg, i.e., fractionation corrected for diet (δ202Hgtissue-δ202Hgdiet) was observed in all tissues with the greatest net fractionation occurring in the mink liver (-1.39‰) and kidney (-0.95‰). Less net fractionation, occurred in the brain (-0.12‰), blood (0.38‰) and fur (0.30‰). In the absence of brain tissue, fur is a suitable proxy which is readily obtainable and can be non-lethally collected. In these mink, it appears that biochemical processes such as demethylation, contribute to significant fractionation of Hg in the liver and kidney, but not as much in the brain and fur, where transport of Hg via thiol-containing complexes may be more important.
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Affiliation(s)
- Lan Ma
- Environment & Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON K9L 0G2, Canada
| | - R Douglas Evans
- School of the Environment, Trent University, 1600 West Bank Drive, Peterborough, ON K9L 0G2, Canada.
| | - Wei Wang
- School of the Environment, Trent University, 1600 West Bank Drive, Peterborough, ON K9L 0G2, Canada
| | - R Bastian Georg
- Water Quality Centre, Trent University, 1600 West Bank Drive, Peterborough, ON K9L 0G2, Canada
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17
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Treu G, Krone O, Unnsteinsdóttir ER, Greenwood AD, Czirják GÁ. Correlations between hair and tissue mercury concentrations in Icelandic arctic foxes (Vulpes lagopus). THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 619-620:1589-1598. [PMID: 29107366 DOI: 10.1016/j.scitotenv.2017.10.143] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 10/14/2017] [Accepted: 10/14/2017] [Indexed: 06/07/2023]
Abstract
Monitoring organic pollutants in wildlife is a common approach to evaluate environmental health, chemical exposure and to make hazard assessments. However, pollutant concentrations measured from different tissue types among studies impede direct comparisons of levels and toxicity benchmarks among species and regions. For example, mercury (Hg) is a metal of both natural and anthropogenic origin which poses health risks for marine and arctic biota in particular. Although hair is recognized as the least invasive sample type for Hg exposure measurement in wildlife, measurements in previous studies have used different tissues among individuals and species. This lack of tissue type consistency hinders cross study comparisons. Therefore to systematically evaluate the use of hair in ecotoxicological studies, total mercury (THg) concentrations measured from hair were compared to values obtained from liver and kidney in 35 Icelandic arctic foxes (Vulpes lagopus). THg concentrations varied considerably among tissues with hair and kidney levels generally lower than in liver. Nevertheless, significant correlations among tissue types were observed. THg values in hair were predictive for liver (R2=0.61) and kidney THg levels (R2=0.51) and liver values were a good predictor of THg in kidney (R2=0.77). We provide further evidence that non-invasively collected hair samples reflect the THg levels of internal tissues. We present equations derived from multiple linear regression models that can be used to relate THg levels among tissue types in order to extrapolate THg values from hair to soft tissues. Using these equations, we compare the results of previous studies monitoring THg levels in different tissues of arctic foxes from various regions of the Arctic. Our findings support that hair is a suitable sample matrix for ecotoxicological studies of arctic predators and may be applied in both wildlife welfare and conservation contexts for arctic vulpine species.
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Affiliation(s)
- Gabriele Treu
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany.
| | - Oliver Krone
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany
| | | | - Alex D Greenwood
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany; Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Gábor Á Czirják
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany.
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18
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Graves SD, Kidd KA, Batchelar KL, Cowie AM, O'Driscoll NJ, Martyniuk CJ. Response of oxidative stress transcripts in the brain of wild yellow perch (Perca flavescens) exposed to an environmental gradient of methylmercury. Comp Biochem Physiol C Toxicol Pharmacol 2017; 192:50-58. [PMID: 27939725 DOI: 10.1016/j.cbpc.2016.12.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/30/2016] [Accepted: 12/02/2016] [Indexed: 12/19/2022]
Abstract
Methylmercury (MeHg) exposure and adverse health effects in fishes have been documented, but the molecular mechanisms involved in toxicity have not been fully characterized. The objectives of the current study were to (1) determine whether total Hg (THg) in the muscle was predictive of MeHg concentrations in the brain of wild female yellow perch (Perca flavescens) collected from four lakes in Kejimkujik National Park, a known biological mercury (Hg) hotspot in Nova Scotia, Canada and (2) to determine whether transcripts involved in the oxidative stress response were altered in abundance in fish collected across five lakes representing a MeHg gradient. In female yellow perch, MeHg in whole brain (0.38 to 2.00μg/g wet weight) was positively associated with THg in muscle (0.18 to 2.13μg/g wet weight) (R2=0.61, p<0.01), suggesting that muscle THg may be useful for predicting MeHg concentrations in the brain. Catalase (cat) mRNA levels were significantly lower in brains of perch collected from lakes with high Hg when compared to those individuals from lakes with relatively lower Hg (p=0.02). Other transcripts (cytochrome c oxidase, glutathione peroxidase, glutathione-s-transferase, heat shock protein 70, protein disulfide isomerase, and superoxide dismutase) did not show differential expression in the brain over the gradient. These findings suggest that MeHg may be inversely associated with catalase mRNA abundance in the central nervous system of wild fishes.
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Affiliation(s)
- Stephanie D Graves
- Department of Biology and Canadian Rivers Institute, University of New Brunswick, Saint John, New Brunswick, E2L 4L5, Canada.
| | - Karen A Kidd
- Department of Biology and Canadian Rivers Institute, University of New Brunswick, Saint John, New Brunswick, E2L 4L5, Canada
| | - Katharina L Batchelar
- Department of Biology and Canadian Rivers Institute, University of New Brunswick, Saint John, New Brunswick, E2L 4L5, Canada
| | - Andrew M Cowie
- Department of Biology and Canadian Rivers Institute, University of New Brunswick, Saint John, New Brunswick, E2L 4L5, Canada
| | - Nelson J O'Driscoll
- Department of Earth and Environmental Sciences, Acadia University, Wolfville, Nova Scotia, B4P 2R6, Canada
| | - Christopher J Martyniuk
- Department of Biology and Canadian Rivers Institute, University of New Brunswick, Saint John, New Brunswick, E2L 4L5, Canada; Department of Physiological Sciences and Center for Environmental and Human Toxicology, UF Genetics Institute, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA
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19
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Puga S, Pereira P, Pinto-Ribeiro F, O'Driscoll NJ, Mann E, Barata M, Pousão-Ferreira P, Canário J, Almeida A, Pacheco M. Unveiling the neurotoxicity of methylmercury in fish (Diplodus sargus) through a regional morphometric analysis of brain and swimming behavior assessment. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 180:320-333. [PMID: 27780124 DOI: 10.1016/j.aquatox.2016.10.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 10/11/2016] [Accepted: 10/14/2016] [Indexed: 06/06/2023]
Abstract
The current study aims to shed light on the neurotoxicity of MeHg in fish (white seabream - Diplodus sargus) by the combined assessment of: (i) MeHg toxicokinetics in the brain, (ii) brain morphometry (volume and number of neurons plus glial cells in specific brain regions) and (iii) fish swimming behavior (endpoints associated with the motor performance and the fear/anxiety-like status). Fish were surveyed for all the components after 7 (E7) and 14 (E14) days of dietary exposure to MeHg (8.7μgg-1), as well as after a post-exposure period of 28days (PE28). MeHg was accumulated in the brain of D. sargus after a short time (E7) and reached a maximum at the end of the exposure period (E14), suggesting an efficient transport of this toxicant into fish brain. Divalent inorganic Hg was also detected in fish brain along the experiment (indicating demethylation reactions), although levels were 100-200 times lower than MeHg, which pinpoints the organic counterpart as the great liable for the recorded effects. In this regard, a decreased number of cells in medial pallium and optic tectum, as well as an increased hypothalamic volume, occurred at E7. Such morphometric alterations were followed by an impairment of fish motor condition as evidenced by a decrease in the total swimming time, while the fear/anxiety-like status was not altered. Moreover, at E14 fish swam a greater distance, although no morphometric alterations were found in any of the brain areas, probably due to compensatory mechanisms. Additionally, although MeHg decreased almost two-fold in the brain during post-exposure, the levels were still high and led to a loss of cells in the optic tectum at PE28. This is an interesting result that highlights the optic tectum as particularly vulnerable to MeHg exposure in fish. Despite the morphometric alterations reported in the optic tectum at PE28, no significant changes were found in fish behavior. Globally, the effects of MeHg followed a multiphasic profile, where homeostatic mechanisms prevented circumstantially morphometric alterations in the brain and behavioral shifts. Although it has become clear the complexity of matching brain morphometric changes and behavioral shifts, motor-related alterations induced by MeHg seem to depend on a combination of disruptions in different brain regions.
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Affiliation(s)
- Sónia Puga
- Life and Health Sciences Research Institute (ICVS), School of Medicine, Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Patrícia Pereira
- Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Filipa Pinto-Ribeiro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Nelson J O'Driscoll
- Department of Earth and Environmental Science, Center for Analytical Research on the Environment, K.C. Irving Center, Acadia University, Wolfville, Nova Scotia, Canada
| | - Erin Mann
- Department of Earth and Environmental Science, Center for Analytical Research on the Environment, K.C. Irving Center, Acadia University, Wolfville, Nova Scotia, Canada
| | - Marisa Barata
- IPMA - Aquaculture Research Station, 8700-005 Olhão, Portugal
| | | | - João Canário
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Armando Almeida
- Life and Health Sciences Research Institute (ICVS), School of Medicine, Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Mário Pacheco
- Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
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