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Bottini CLJ, MacDougall-Shackleton SA. Methylmercury effects on avian brains. Neurotoxicology 2023; 96:140-153. [PMID: 37059311 DOI: 10.1016/j.neuro.2023.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 04/03/2023] [Accepted: 04/11/2023] [Indexed: 04/16/2023]
Abstract
Methylmercury (MeHg) is a concerning contaminant due to its ubiquity and harmful effects on organisms. Although birds are important models in the neurobiology of vocal learning and adult neuroplasticity, the neurotoxic effects of MeHg are less understood in birds than mammals. We surveyed the literature on MeHg effects on biochemical changes in the avian brain. Publication rates of papers related to neurology and/or birds and/or MeHg increased with time and can be linked with historical events, regulations, and increased understanding of MeHg cycling in the environment. However, publications on MeHg effects on the avian brain remain relatively low across time. The neural effects measured to evaluate MeHg neurotoxicity in birds changed with time and researcher interest. The measures most consistently affected by MeHg exposure in birds were markers of oxidative stress. NMDA, acetylcholinesterase, and Purkinje cells also seem sensitive to some extent. MeHg exposure has the potential to affect most neurotransmitter systems but more studies are needed for validation in birds. We also review the main mechanisms of MeHg-induced neurotoxicity in mammals and compare it to what is known in birds. The literature on MeHg effects on the avian brain is limited, preventing full construction of an adverse outcome pathway. We identify research gaps for taxonomic groups such as songbirds, and age- and life-stage groups such as immature fledgling stage and adult non-reproductive life stage. In addition, results are often inconsistent between experimental and field studies. We conclude that future neurotoxicological studies of MeHg impacts on birds need to better connect the numerous aspects of exposure from molecular physiological effects to behavioural outcomes that would be ecologically or biologically relevant for birds, especially under challenging conditions.
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Affiliation(s)
- Claire L J Bottini
- University of Western Ontario, Department of Biology, 1151 Richmond St., London Ontario, N6A 5B7; Advanced Facility for Avian Research, University of Western Ontario, London, Ontario, Canada.
| | - Scott A MacDougall-Shackleton
- Advanced Facility for Avian Research, University of Western Ontario, London, Ontario, Canada; University of Western Ontario, Department of Psychology, 1151 Richmond St., London Ontario, N6A 5C2
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Han B, van den Berg H, Loonen MJ, Mateo R, van den Brink NW. Mercury-Modulated Immune Responses in Arctic Barnacle Goslings ( Branta leucopsis) upon a Viral-Like Immune Challenge. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:5337-5348. [PMID: 36940419 PMCID: PMC10077589 DOI: 10.1021/acs.est.2c07622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 03/10/2023] [Accepted: 03/10/2023] [Indexed: 06/18/2023]
Abstract
Historical mining activities in Svalbard (79°N/12°E) have caused local mercury (Hg) contamination. To address the potential immunomodulatory effects of environmental Hg on Arctic organisms, we collected newborn barnacle goslings (Branta leucopsis) and herded them in either a control or mining site, differing in Hg levels. An additional group at the mining site was exposed to extra inorganic Hg(II) via supplementary feed. Hepatic total Hg concentrations differed significantly between the control (0.011 ± 0.002 mg/kg dw), mine (0.043 ± 0.011 mg/kg dw), and supplementary feed (0.713 ± 0.137 mg/kg dw) gosling groups (average ± standard deviation). Upon immune challenge with double-stranded RNA (dsRNA) injection, endpoints for immune responses and oxidative stress were measured after 24 h. Our results indicated that Hg exposure modulated the immune responses in Arctic barnacle goslings upon a viral-like immune challenge. Increased exposure to both environmental as well as supplemental Hg reduced the level of natural antibodies, suggesting impaired humoral immunity. Hg exposure upregulated the expression of proinflammatory genes in the spleen, including inducible nitric oxide synthase (iNOS) and interleukin 18 (IL18), suggesting Hg-induced inflammatory effects. Exposure to Hg also oxidized glutathione (GSH) to glutathione disulfide (GSSG); however, goslings were capable of maintaining the redox balance by de novo synthesis of GSH. These adverse effects on the immune responses indicated that even exposure to low, environmentally relevant levels of Hg might affect immune competence at the individual level and might even increase the susceptibility of the population to infections.
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Affiliation(s)
- Biyao Han
- Wageningen
University, Division of Toxicology, Postal code 8000, NL-6700 EA Wageningen, The Netherlands
| | - Hans van den Berg
- Wageningen
University, Division of Toxicology, Postal code 8000, NL-6700 EA Wageningen, The Netherlands
| | - Maarten J.J.E. Loonen
- University
of Groningen, Arctic Centre, Aweg 30, NL-9718 CW Groningen, The Netherlands
| | - Rafael Mateo
- Instituto
de Investigación en Recursos Cinegéticos (IREC), Ronda de Toledo, 12, 13071 Ciudad Real, Spain
| | - Nico W. van den Brink
- Wageningen
University, Division of Toxicology, Postal code 8000, NL-6700 EA Wageningen, The Netherlands
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Dias Dos Santos AN, Recktenvald MCNDN, de Carvalho DP, Bortoleto Puerta EL, de Sousa-Filho IF, Dórea JG, Bastos WR. Mercury in birds (aquatic and scavenger) from the Western Amazon. ENVIRONMENTAL RESEARCH 2021; 201:111574. [PMID: 34181920 DOI: 10.1016/j.envres.2021.111574] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 06/19/2021] [Accepted: 06/19/2021] [Indexed: 06/13/2023]
Abstract
In the Amazon rainforest, methylmercury (MeHg) is easily biomagnified and bio-accumulated in the aquatic food chain. This unique biome has been studied for occupational and environmental issues related to human health and contamination through fish consumption; however, wildlife studies have not yet addressed fish-eating birds. Different species of birds categorized by foraging strategies and life-stages were studied in the Madeira River Basin (Western Amazon rainforest). Feather and tissue (muscle, liver, kidneys, lungs, heart, brain, and blood) samples were collected opportunistically from six bird species feeding on fish and aquatic fauna and a scavenger (a saprophagous species) during the low-water season (July 2017). All collected samples were analyzed for total Hg (THg); methyl-Hg (MeHg) was determined only in feathers. The mean THg concentrations in feathers (dw) were as follows: Ardea cocoi (4.05 μg g-1, n = 51) > Egretta thulla (3.94 μg g-1, n = 5) > Ardea alba (3.80 μg g-1, n = 61) > Anhinga anhinga (3.69 μg g-1, n = 8) > Nannopterum brasilianus (3.07 μg g-1, n = 10). The scavenger Coragyps atratus showed mean THg in feathers (9.93 μg g-1, n = 30) to be significantly higher than in fish-eating birds. Across species, THg levels in feathers correlated significantly with THgmuscle (p = 0.022) and THgbrain (p = 0.002). THg concentrations varied in tissues (feather > liver > kidneys > lungs > heart > muscle > blood > brain). The Hgbrain:Hgfeather, Hgbrain:Hgmuscle, and Hgbrain:Hgblood ratios were 0.031, 0.503 and 0.516, respectively. The mean [MeHg:THg] ratio in feathers from aquatic birds varied between species from 14 to 74% with a mean of 38%. Scavenger birds that forage in the terrestrial Amazonian environments concentrate more THg than species that forage in the aquatic environment. None of the aquatic species showed THg concentration in internal organs that were above threshold for risk of Hg toxicity; additionally, they are not listed in the categories of threat by the International Union for Conservation of Nature (IUCN).
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Affiliation(s)
- Angela N Dias Dos Santos
- Laboratório de Biogeoquímica Ambiental Wolfgang C. Pfeiffer, Fundação Universidade Federal de Rondônia, Porto Velho, Brazil
| | | | | | | | - Izidro F de Sousa-Filho
- Laboratório de Biogeoquímica Ambiental Wolfgang C. Pfeiffer, Fundação Universidade Federal de Rondônia, Porto Velho, Brazil
| | - José G Dórea
- Faculdade de Ciências da Saúde, Universidade de Brasília, Brazil
| | - Wanderley R Bastos
- Laboratório de Biogeoquímica Ambiental Wolfgang C. Pfeiffer, Fundação Universidade Federal de Rondônia, Porto Velho, Brazil.
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Steenhuisen F, van den Heuvel-Greve M. Exposure radius of a local coal mine in an Arctic coastal system; correlation between PAHs and mercury as a marker for a local mercury source. ENVIRONMENTAL MONITORING AND ASSESSMENT 2021; 193:499. [PMID: 34291327 PMCID: PMC8295130 DOI: 10.1007/s10661-021-09287-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 07/12/2021] [Indexed: 05/26/2023]
Abstract
Mercury in the Arctic originates from emissions and releases at lower latitudes and, to a lesser extent, from local and regional sources. The relationship between mercury (Hg) and polycyclic aromatic hydrocarbons (PAHs) in sediment can be applied as an indicator of the mercury source. This research examines the Hg contamination gradient from a land-based coal mine to the surrounding coastal environment to quantify the impact of local sources. Total mercury and PAH (Σ14PAH) were measured in terrestrial and marine sediments as well as in marine biota. Samples were collected at the mine and two reference sites. Mercury and Σ14PAH concentrations in samples collected at the mine site were significantly higher than those at the reference sites. This was also found in the biota samples, although less pronounced. This work addresses the complexities of interpreting data concerning very low contaminant levels in a relatively pristine environment. A clear correlation between PAH and Hg concentration in sediment was found, although a large number of samples had levels below detection limits. PAH profiles, hierarchical clustering, and molecular diagnostic ratios provided further insight into the origin of PAHs and Hg, showing that signatures in sediments from the nearest reference site were more similar to the mine, which was not the case for the other reference site. The observed exposure radius from the mine was small and diluted from land to water to marine biota. Due to low contamination levels and variable PAH profiles, marine biota was less suitable for tracing the exposure radius for this local land-based Hg source. With an expected increase in mobility and availability of contaminants in the warming Arctic, changes in input of PAHs and Hg from land-based sources to the marine system need close monitoring.
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Affiliation(s)
- Frits Steenhuisen
- Arctic Centre, University of Groningen, Aweg 30, 9718, CW, Groningen, the Netherlands.
| | - Martine van den Heuvel-Greve
- Wageningen Marine Research, P.O. Box 77, 4400 AB, Yerseke, The Netherlands
- Marine Animal Ecology, Wageningen University, P.O. Box 338, 6700 AH, Wageningen, The Netherlands
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Doyle S, Gray A, McMahon BJ. Anthropogenic impacts on the demographics of Arctic-breeding birds. Polar Biol 2020. [DOI: 10.1007/s00300-020-02756-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Lippold A, Aars J, Andersen M, Aubail A, Derocher AE, Dietz R, Eulaers I, Sonne C, Welker JM, Wiig Ø, Routti H. Two Decades of Mercury Concentrations in Barents Sea Polar Bears ( Ursus maritimus) in Relation to Dietary Carbon, Sulfur, and Nitrogen. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:7388-7397. [PMID: 32410455 DOI: 10.1021/acs.est.0c01848] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Temporal trends of total mercury (THg) were examined in female polar bear (Ursus maritimus) hair (n = 199) from the Barents Sea in 1995-2016. In addition, hair values of stable isotopes (n = 190-197) of carbon (δ13C), sulfur (δ34S), and nitrogen (δ15N) and information on breeding status, body condition, and age were obtained. Stable isotope values of carbon and sulfur reflect dietary source (e.g., marine vs terrestrial) and the nitrogen trophic level. Values for δ13C and δ34S declined by -1.62 and -1.18‰ over the time of the study period, respectively, while values for δ15N showed no trend. Total Hg concentrations were positively related to both δ13C and δ34S. Yearly median THg concentrations ranged from 1.61 to 2.75 μg/g and increased nonlinearly by 0.86 μg/g in total over the study. Correcting THg concentrations for stable isotope values of carbon and sulfur and additionally breeding status and age slightly accelerated the increase in THg concentrations; however, confidence intervals of the raw THg trend and the corrected THg trend had substantial overlap. The rise in THg concentrations in the polar bear food web was possibly related to climate-related re-emissions of previously stored Hg from thawing sea-ice, glaciers, and permafrost.
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Affiliation(s)
- Anna Lippold
- Fram Centre, Norwegian Polar Institute, Tromsø 9296, Norway
| | - Jon Aars
- Fram Centre, Norwegian Polar Institute, Tromsø 9296, Norway
| | | | - Aurore Aubail
- Littoral, Environment and Societies (CNRS/La Rochelle University), La Rochelle 17000, France
| | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta, Edmonton T6G 2E9, Canada
| | - Rune Dietz
- Institute of Bioscience, Arctic Research Centre, Aarhus University, Roskilde 4000, Denmark
| | - Igor Eulaers
- Institute of Bioscience, Arctic Research Centre, Aarhus University, Roskilde 4000, Denmark
| | - Christian Sonne
- Institute of Bioscience, Arctic Research Centre, Aarhus University, Roskilde 4000, Denmark
| | - Jeffrey M Welker
- University of Alaska Anchorage, Anchorage 99508, United States
- University of Oulu, Oulu 90014, Finland
- University of the Arctic, Rovaniemi 96460, Finland
| | - Øystein Wiig
- Fram Centre, Norwegian Polar Institute, Tromsø 9296, Norway
- Natural History Museum, University of Oslo, 0318 Oslo, Norway
| | - Heli Routti
- Fram Centre, Norwegian Polar Institute, Tromsø 9296, Norway
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Scheiber IBR, Weiß BM, de Jong ME, Braun A, van den Brink NW, Loonen MJJE, Millesi E, Komdeur J. Stress behaviour and physiology of developing Arctic barnacle goslings ( Branta leucopsis) is affected by legacy trace contaminants. Proc Biol Sci 2018; 285:20181866. [PMID: 30963902 PMCID: PMC6304058 DOI: 10.1098/rspb.2018.1866] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 11/12/2018] [Indexed: 11/23/2022] Open
Abstract
Natural populations are persistently exposed to environmental pollution, which may adversely impact animal physiology and behaviour and even compromise survival. Responding appropriately to any stressor ultimately might tip the scales for survival, as mistimed behaviour and inadequate physiological responses may be detrimental. Yet effects of legacy contamination on immediate physiological and behavioural stress coping abilities during acute stress are virtually unknown. Here, we assessed these effects in barnacle goslings ( Branta leucopsis) at a historical coal mine site in the Arctic. For three weeks we led human-imprinted goslings, collected from nests in unpolluted areas, to feed in an abandoned coal mining area, where they were exposed to trace metals. As control we led their siblings to feed on clean grounds. After submitting both groups to three well-established stress tests (group isolation, individual isolation, on-back restraint), control goslings behaved calmer and excreted lower levels of corticosterone metabolites. Thus, legacy contamination may decisively change stress physiology and behaviour in long-lived vertebrates exposed at a young age.
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Affiliation(s)
- Isabella B. R. Scheiber
- Behavioural and Physiological Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, The Netherlands
- Department of Behavioural Biology, Faculty of Life Sciences, University of Vienna, 1090 Vienna, Austria
| | - Brigitte M. Weiß
- Behavioural Ecology Research Group, University of Leipzig, 04103 Leipzig, Germany
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
| | - Margje E. de Jong
- Arctic Centre, University of Groningen, 9718 CW Groningen, The Netherlands
| | - Anna Braun
- Behavioural and Physiological Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Nico W. van den Brink
- Department of Toxicology, Wageningen University, 6700 EA Wageningen, The Netherlands
| | | | - Eva Millesi
- Department of Behavioural Biology, Faculty of Life Sciences, University of Vienna, 1090 Vienna, Austria
| | - Jan Komdeur
- Behavioural and Physiological Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, The Netherlands
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