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Ackerman JT, Peterson SH, Herzog MP, Yee JL. Methylmercury Effects on Birds: A Review, Meta-Analysis, and Development of Toxicity Reference Values for Injury Assessment Based on Tissue Residues and Diet. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2024. [PMID: 38682592 DOI: 10.1002/etc.5858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/08/2023] [Accepted: 02/20/2024] [Indexed: 05/01/2024]
Abstract
Birds are used as bioindicators of environmental mercury (Hg) contamination, and toxicity reference values are needed for injury assessments. We conducted a comprehensive review, summarized data from 168 studies, performed a series of Bayesian hierarchical meta-analyses, and developed new toxicity reference values for the effects of methylmercury (MeHg) on birds using a benchmark dose analysis framework. Lethal and sublethal effects of MeHg on birds were categorized into nine biologically relevant endpoint categories and three age classes. Effective Hg concentrations where there was a 10% reduction (EC10) in the production of juvenile offspring (0.55 µg/g wet wt adult blood-equivalent Hg concentrations, 80% credible interval: [0.33, 0.85]), histology endpoints (0.49 [0.15, 0.96] and 0.61 [0.09, 2.48]), and biochemical markers (0.77 [<0.25, 2.12] and 0.57 [0.35, 0.92]) were substantially lower than those for survival (2.97 [2.10, 4.73] and 5.24 [3.30, 9.55]) and behavior (6.23 [1.84, >13.42] and 3.11 [2.10, 4.64]) of juveniles and adults, respectively. Within the egg age class, survival was the most sensitive endpoint (EC10 = 2.02 µg/g wet wt adult blood-equivalent Hg concentrations [1.39, 2.94] or 1.17 µg/g fresh wet wt egg-equivalent Hg concentrations [0.80, 1.70]). Body morphology was not particularly sensitive to Hg. We developed toxicity reference values using a combined survival and reproduction endpoints category for juveniles, because juveniles were more sensitive to Hg toxicity than eggs or adults. Adult blood-equivalent Hg concentrations (µg/g wet wt) and egg-equivalent Hg concentrations (µg/g fresh wet wt) caused low injury to birds (EC1) at 0.09 [0.04, 0.17] and 0.04 [0.01, 0.08], moderate injury (EC5) at 0.6 [0.37, 0.84] and 0.3 [0.17, 0.44], high injury (EC10) at 1.3 [0.94, 1.89] and 0.7 [0.49, 1.02], and severe injury (EC20) at 3.2 [2.24, 4.78] and 1.8 [1.28, 2.79], respectively. Maternal dietary Hg (µg/g dry wt) caused low injury to juveniles at 0.16 [0.05, 0.38], moderate injury at 0.6 [0.29, 1.03], high injury at 1.1 [0.63, 1.87], and severe injury at 2.4 [1.42, 4.13]. We found few substantial differences in Hg toxicity among avian taxonomic orders, including for controlled laboratory studies that injected Hg into eggs. Our results can be used to quantify injury to birds caused by Hg pollution. Environ Toxicol Chem 2024;00:1-52. Published 2024. This article is a U.S. Government work and is in the public domain in the USA. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Affiliation(s)
- Joshua T Ackerman
- US Geological Survey, Western Ecological Research Center, Dixon Field Station, Dixon, California, USA
| | - Sarah H Peterson
- US Geological Survey, Western Ecological Research Center, Dixon Field Station, Dixon, California, USA
| | - Mark P Herzog
- US Geological Survey, Western Ecological Research Center, Dixon Field Station, Dixon, California, USA
| | - Julie L Yee
- US Geological Survey, Western Ecological Research Center, Santa Cruz Field Station, Santa Cruz, California, USA
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Li S, Zhang F, Xu Z, Jia D, Wu G, Liu H, Li C, Liang L, Liu J, Chen Z, Qiu G. Using live videography observation and Bayesian isotope mixing model to identify food composition and dietary contribution to inorganic mercury and methylmercury intake by songbird nestlings. ENVIRONMENTAL RESEARCH 2024; 244:117902. [PMID: 38092237 DOI: 10.1016/j.envres.2023.117902] [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: 10/16/2023] [Revised: 11/30/2023] [Accepted: 12/07/2023] [Indexed: 12/17/2023]
Abstract
Mercury (Hg) exposure is increasing in terrestrial birds; however, studies on its sources are scarce. In the present study, we elucidated the food composition of green-backed tit nestlings from three urban forest parks (CPL, AHL, and LCG) using live videography observation (LVO). Furthermore, the daily dietary intakes of inorganic Hg (IHg) (MDIIHg) and methylmercury (MeHg) (MDIMeHg) were determined using the Bayesian isotope mixing model (BIMM) to uncover the nestlings' specific dietary Hg contribution. Both LVO and BIMM indicated that Lepidoptera (primarily caterpillar) constituted the primary food source for the nestlings in the three forests, accounting for approximately 60% of their diet in all three forest parks. The estimated MDI of Hg revealed that lepidopterans and spiders primarily contributed to IHg exposure, with a co-contribution ratio of 71.8%-97.7%. Unexpectedly, dietary MeHg was mostly derived from spiders; the highest contribution ratio of 93.6% was recorded at CPL, followed by another peak ratio of 92.9% at LCG. However, the dietary exposure was primarily IHg, accounting for 69.8% (AHL), 62.0% (LCG), and 61.3% (CPL) of the nestlings. Our study findings highlight the importance of dietary IHg transfer in evaluating the effects of Hg in nestlings. LVO, coupled with BIMM, is an effective tool for determining the food compositions of songbird nestlings and estimating the contribution of specific diets.
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Affiliation(s)
- Shenghao Li
- School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China
| | - Fudong Zhang
- College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China
| | - Zhidong Xu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Dongya Jia
- School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China
| | - Gaoen Wu
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, 570228, China
| | - Hongjiang Liu
- School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China
| | - Chan Li
- School of Ecology and Environmental Science, Yunnan University, Kunming, 650091, China
| | - Longchao Liang
- School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China
| | - Jiemin Liu
- Guizhou Provincial People's Hospital, Guiyang, 550002, China
| | - Zhuo Chen
- School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China.
| | - Guangle Qiu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
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Grunst AS, Grunst ML, Fort J. Contaminant-by-environment interactive effects on animal behavior in the context of global change: Evidence from avian behavioral ecotoxicology. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 879:163169. [PMID: 37003321 DOI: 10.1016/j.scitotenv.2023.163169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 03/01/2023] [Accepted: 03/26/2023] [Indexed: 05/17/2023]
Abstract
The potential for chemical contaminant exposure to interact with other stressors to affect animal behavioral responses to environmental variability is of mounting concern in the context of anthropogenic environmental change. We systematically reviewed the avian literature to evaluate evidence for contaminant-by-environment interactive effects on animal behavior, as birds are prominent models in behavioral ecotoxicology and global change research. We found that only 17 of 156 (10.9 %) avian behavioral ecotoxicological studies have explored contaminant-by-environment interactions. However, 13 (76.5 %) have found evidence for interactive effects, suggesting that contaminant-by-environment interactive effects on behavior are understudied but important. We draw on our review to develop a conceptual framework to understand such interactive effects from a behavioral reaction norm perspective. Our framework highlights four patterns in reaction norm shapes that can underlie contaminant-by-environment interactive effects on behavior, termed exacerbation, inhibition, mitigation and convergence. First, contamination can render individuals unable to maintain critical behaviors across gradients in additional stressors, exacerbating behavioral change (reaction norms steeper) and generating synergy. Second, contamination can inhibit behavioral adjustment to other stressors, antagonizing behavioral plasticity (reaction norms shallower). Third, a second stressor can mitigate (antagonize) toxicological effects of contamination, causing steeper reaction norms in highly contaminated individuals, with improvement of performance upon exposure to additional stress. Fourth, contamination can limit behavioral plasticity in response to permissive conditions, such that performance of more and less contaminated individuals converges under more stressful conditions. Diverse mechanisms might underlie such shape differences in reaction norms, including combined effects of contaminants and other stressors on endocrinology, energy balance, sensory systems, and physiological and cognitive limits. To encourage more research, we outline how the types of contaminant-by-environment interactive effects proposed in our framework might operate across multiple behavioral domains. We conclude by leveraging our review and framework to suggest priorities for future research.
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Affiliation(s)
- Andrea S Grunst
- Littoral, Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, 2 Rue Olympe de Gouges, FR-17000 La Rochelle, France.
| | - Melissa L Grunst
- Littoral, Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, 2 Rue Olympe de Gouges, FR-17000 La Rochelle, France
| | - Jérôme Fort
- Littoral, Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, 2 Rue Olympe de Gouges, FR-17000 La Rochelle, France
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Li C, Luo K, Shao Y, Xu X, Chen Z, Liang T, Xu Z, Dong X, Wang H, Qiu G. Total and methylmercury concentrations in nocturnal migratory birds passing through Mount Ailao, Southwest China. ENVIRONMENTAL RESEARCH 2022; 215:114373. [PMID: 36165871 DOI: 10.1016/j.envres.2022.114373] [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: 05/16/2022] [Revised: 09/14/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Abstract
Despite growing concerns over mercury (Hg) accumulation in birds in recent decades, little is known about Hg exposure in nocturnal migratory birds. Here, total mercury (THg) and methylmercury (MeHg) were detected in the feathers of nocturnal migratory birds (n = 286, belonging to 46 species) passing through Mount Ailao in Southwest China. The stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) were also determined to clarify the effects of trophic position, foraging guild, and foraging behavior on Hg bioaccumulation. Our results show that the THg and MeHg concentrations varied by two orders of magnitude among all nocturnal migratory birds investigated, with the lowest values (THg: 0.056 mg kg-1; MeHg: 0.038 mg kg-1) in the Asian koel (Eudynamys scolopaceus) and the highest (THg: 12 mg kg-1; MeHg: 7.8 mg kg-1) in the hair-crested drongo (Dicrurus hottentottus). Waterbirds showed higher δ15N values and higher THg and MeHg concentrations than songbirds, and the Hg concentrations in piscivorous species were significantly higher than those in herbivores, omnivores, and insectivores. Significant effects of foraging guilds (Kruskal-Wallis one-way ANOVA, p < 0.001) and foraging behaviors (Kruskal-Wallis one-way ANOVA, p < 0.001) on the Hg concentrations in migratory bird feathers were detected. A risk assessment indicated that approximately 7.0% of individuals were at moderate (2.4-5.0 mg kg-1) to high (>5.0 mg kg-1) risk of Hg exposure, and were therefore vulnerable to adverse physiological and behavioral effects. A long-term monitoring campaign during the migratory period is highly recommended to better understand the bioaccumulation of Hg in these nocturnal migratory bird populations over time.
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Affiliation(s)
- Chan Li
- School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China
| | - Kang Luo
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuxiao Shao
- School of Geography and Environmental Science, Guizhou Normal University, Guiyang, 550001, China
| | - Xiaohang Xu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhuo Chen
- School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China.
| | - Tao Liang
- Zhenyuan Management and Protection Bureau of Ailao Mountain National Nature Reserve, Zhenyuan, 666500, China
| | - Zhidong Xu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xian Dong
- School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China
| | - Hongdong Wang
- Zhenyuan Management and Protection Bureau of Ailao Mountain National Nature Reserve, Zhenyuan, 666500, China
| | - Guangle Qiu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
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Chastel O, Fort J, Ackerman JT, Albert C, Angelier F, Basu N, Blévin P, Brault-Favrou M, Bustnes JO, Bustamante P, Danielsen J, Descamps S, Dietz R, Erikstad KE, Eulaers I, Ezhov A, Fleishman AB, Gabrielsen GW, Gavrilo M, Gilchrist G, Gilg O, Gíslason S, Golubova E, Goutte A, Grémillet D, Hallgrimsson GT, Hansen ES, Hanssen SA, Hatch S, Huffeldt NP, Jakubas D, Jónsson JE, Kitaysky AS, Kolbeinsson Y, Krasnov Y, Letcher RJ, Linnebjerg JF, Mallory M, Merkel FR, Moe B, Montevecchi WJ, Mosbech A, Olsen B, Orben RA, Provencher JF, Ragnarsdottir SB, Reiertsen TK, Rojek N, Romano M, Søndergaard J, Strøm H, Takahashi A, Tartu S, Thórarinsson TL, Thiebot JB, Will AP, Wilson S, Wojczulanis-Jakubas K, Yannic G. Mercury contamination and potential health risks to Arctic seabirds and shorebirds. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 844:156944. [PMID: 35752241 DOI: 10.1016/j.scitotenv.2022.156944] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/20/2022] [Accepted: 06/20/2022] [Indexed: 06/15/2023]
Abstract
Since the last Arctic Monitoring and Assessment Programme (AMAP) effort to review biological effects of mercury (Hg) on Arctic biota in 2011 and 2018, there has been a considerable number of new Arctic bird studies. This review article provides contemporary Hg exposure and potential health risk for 36 Arctic seabird and shorebird species, representing a larger portion of the Arctic than during previous AMAP assessments now also including parts of the Russian Arctic. To assess risk to birds, we used Hg toxicity benchmarks established for blood and converted to egg, liver, and feather tissues. Several Arctic seabird populations showed Hg concentrations that exceeded toxicity benchmarks, with 50 % of individual birds exceeding the "no adverse health effect" level. In particular, 5 % of all studied birds were considered to be at moderate or higher risk to Hg toxicity. However, most seabirds (95 %) were generally at lower risk to Hg toxicity. The highest Hg contamination was observed in seabirds breeding in the western Atlantic and Pacific Oceans. Most Arctic shorebirds exhibited low Hg concentrations, with approximately 45 % of individuals categorized at no risk, 2.5 % at high risk category, and no individual at severe risk. Although the majority Arctic-breeding seabirds and shorebirds appeared at lower risk to Hg toxicity, recent studies have reported deleterious effects of Hg on some pituitary hormones, genotoxicity, and reproductive performance. Adult survival appeared unaffected by Hg exposure, although long-term banding studies incorporating Hg are still limited. Although Hg contamination across the Arctic is considered low for most bird species, Hg in combination with other stressors, including other contaminants, diseases, parasites, and climate change, may still cause adverse effects. Future investigations on the global impact of Hg on Arctic birds should be conducted within a multi-stressor framework. This information helps to address Article 22 (Effectiveness Evaluation) of the Minamata Convention on Mercury as a global pollutant.
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Affiliation(s)
- Olivier Chastel
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 CNRS- La Rochelle Université, 79360 Villiers-en-Bois, France.
| | - Jérôme Fort
- Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, 17000 La Rochelle, France.
| | - 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.
| | - Céline Albert
- Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, 17000 La Rochelle, France
| | - Frédéric Angelier
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 CNRS- La Rochelle Université, 79360 Villiers-en-Bois, France
| | - Niladri Basu
- McGill University, Faculty of Agriculture and Environmental Sciences, Montreal, QC H9X 3V9, Canada
| | | | - Maud Brault-Favrou
- Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, 17000 La Rochelle, France
| | - Jan Ove Bustnes
- Norwegian Institute for Nature Research, FRAM Centre, 9296 Tromsø, Norway
| | - Paco Bustamante
- Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, 17000 La Rochelle, France; Institut Universitaire de France (IUF), 75005 Paris, France
| | | | | | - Rune Dietz
- Department of Ecoscience, Aarhus University, 4000 Roskilde, Denmark
| | | | - Igor Eulaers
- Norwegian Polar Institute, Fram center, 9296 Tromsø, Norway; Department of Ecoscience, Aarhus University, 4000 Roskilde, Denmark
| | - Alexey Ezhov
- Murmansk Marine Biological Institute Russian Academy of Science, 183010 Vladimirskaya str. 17 Murmansk, Russia
| | - Abram B Fleishman
- Conservation Metrics, Inc., Santa Cruz, CA, United States of America
| | | | - Maria Gavrilo
- Arctic and Antarctic Research Institute, 199397 St. Petersburg, Russia
| | - Grant Gilchrist
- Environment and Climate Change Canada, National Wildlife Research Centre, 1125 Colonel By Drive, Raven Road, Carleton University, Ottawa, Ont., Canada K1A 0H3
| | - Olivier Gilg
- Laboratoire Chrono-environnement, UMR 6249, Université de Bourgogne Franche Comté, 25000 Besançon, France; Groupe de Recherche en Ecologie Arctique, 16 rue de Vernot, F-21440 Francheville, France
| | - Sindri Gíslason
- Southwest Iceland Nature Research Centre, Gardvegur 1, 245 Sudurnesjabaer, Iceland
| | - Elena Golubova
- Laboratory of Ornithology, Institute of Biological Problems of the North, RU-685000 Magadan, Portovaya Str., 18, Russia
| | - Aurélie Goutte
- EPHE, PSL Research University, UMR 7619 METIS, F-75005 Paris, France
| | - David Grémillet
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR 5175 Univ Montpellier, CNRS, EPHE, IRD, Montpellier, France,; Percy FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch, South Africa
| | - Gunnar T Hallgrimsson
- Department of Life and Environmental Sciences, University of Iceland, 102 Reykjavik, Iceland
| | - Erpur S Hansen
- South Iceland Nature Research Centre, Ægisgata 2, 900 Vestmannaeyjar, Iceland
| | | | - Scott Hatch
- Institute for Seabird Research and Conservation, Anchorage, 99516-3185, AK, USA
| | - Nicholas P Huffeldt
- Department of Ecoscience, Aarhus University, 4000 Roskilde, Denmark; Greenland Institute of Natural Resources, 3900 Nuuk, Greenland
| | - Dariusz Jakubas
- Department of Vertebrate Ecology and Zoology, University of Gdansk, 80-308 Gdansk, Poland
| | - Jón Einar Jónsson
- University of Iceland's Research Center at Snæfellsnes, 340 Stykkishólmur, Iceland
| | - Alexander S Kitaysky
- University of Alaska Fairbanks, Institute of Arctic Biology, Department of Biology & Wildlife, Fairbanks, AK 99775-7000, United States of America
| | | | - Yuri Krasnov
- Murmansk Marine Biological Institute Russian Academy of Science, 183010 Vladimirskaya str. 17 Murmansk, Russia
| | - Robert J Letcher
- Environment and Climate Change Canada, National Wildlife Research Centre, 1125 Colonel By Drive, Raven Road, Carleton University, Ottawa, Ont., Canada K1A 0H3
| | | | - Mark Mallory
- Biology, Acadia University Wolfville, Nova Scotia B4P 2R6, Canada
| | - Flemming Ravn Merkel
- Department of Ecoscience, Aarhus University, 4000 Roskilde, Denmark; Greenland Institute of Natural Resources, 3900 Nuuk, Greenland
| | - Børge Moe
- Norwegian Institute for Nature Research, 7485 Trondheim, Norway
| | - William J Montevecchi
- Memorial Univerisity of Newfoundland and Labrador, St. John's, Newoundland A1C 3X9, Canada
| | - Anders Mosbech
- Department of Ecoscience, Aarhus University, 4000 Roskilde, Denmark
| | - Bergur Olsen
- Faroe Marine Reseaqrch Institute, Nóatún 1, FO-110 Tórshavn, Faroe Islands
| | - Rachael A Orben
- Department of Fisheries, Wildlife and Conservation Sciences, Oregon State University, Hatfield Marine Science Center, Newport, OR, USA
| | - Jennifer F Provencher
- Science & Technology Branch, Environment and Climate Change Canada, Ottawa, Ontario, Canada K1A 0H3
| | | | - Tone K Reiertsen
- Norwegian Institute for Nature Research, FRAM Centre, 9296 Tromsø, Norway
| | - Nora Rojek
- U.S. Fish and Wildlife Service, Alaska Maritime Wildlife Refuge, Homer, AK, USA
| | - Marc Romano
- U.S. Fish and Wildlife Service, Alaska Maritime Wildlife Refuge, Homer, AK, USA
| | - Jens Søndergaard
- Department of Ecoscience, Aarhus University, 4000 Roskilde, Denmark
| | - Hallvard Strøm
- Norwegian Polar Institute, Fram center, 9296 Tromsø, Norway
| | - Akinori Takahashi
- National Institute of Polar Research, 10-3 Midori-cho, Tachikawa, Tokyo 190-8518, Japan
| | - Sabrina Tartu
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 CNRS- La Rochelle Université, 79360 Villiers-en-Bois, France
| | | | - Jean-Baptiste Thiebot
- National Institute of Polar Research, 10-3 Midori-cho, Tachikawa, Tokyo 190-8518, Japan
| | - Alexis P Will
- University of Alaska Fairbanks, Institute of Arctic Biology, Department of Biology & Wildlife, Fairbanks, AK 99775-7000, United States of America; National Institute of Polar Research, 10-3 Midori-cho, Tachikawa, Tokyo 190-8518, Japan
| | - Simon Wilson
- Arctic Monitoring and Assessment Programme (AMAP) Secretariat, The Fram Centre, Box 6606, Stakkevollan, 9296, Tromsø, Norway
| | | | - Glenn Yannic
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LECA, 38000 Grenoble, France
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Ma Y, Choi CY, Thomas A, Gibson L. Review of contaminant levels and effects in shorebirds: Knowledge gaps and conservation priorities. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 242:113868. [PMID: 35863215 DOI: 10.1016/j.ecoenv.2022.113868] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 06/20/2022] [Accepted: 07/05/2022] [Indexed: 06/15/2023]
Abstract
Environmental pollution has emerged as a major threat to bird populations. Many shorebird populations are declining, although contamination has been documented in some shorebirds, evidence of negative impacts is sparse and this important topic remains understudied. To guide future research and develop effective conservation strategies, we carried out a comprehensive review of environmental pollutants and their consequences on shorebirds. In total, we found 93 relevant articles which examined pollutant contamination in ~37% (79 of 215) of all shorebird species, mostly from the Charadriidae and Scolopacidae families. Studies were geographically biased: the majority were conducted in American flyways, while only 1 was found from Australasia and few were conducted in Asian flyways. The main geographic gap for research includes East Africa, South Asia and Siberian Arctic. The most well-documented pollutants included mercury (Hg, 37 studies), cadmium (33), and lead (Pb, 28); less well studied pollutants were barium (1), calcium (1), strontium (1), dicofols (1), and other newly emerging contaminants, such as plastic debris/microplastics (4) and antibiotics resistance (2). Several pollutants have caused considerable concerns in shorebirds, including embryotoxicity caused by PCBs at non-optimum temperature (laboratory experiments); reduced reproduction performance linked to maternal Hg and paternal Pb (field evidence); and reduced refueling and flight performance related to oil contamination (both field and laboratory evidence). Our results confirm that an in-depth understanding of the local, regional and global factors that influence population trends of shorebirds in light of increasing pollution threats is essential for accurate and effective management and conservation strategies.
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Affiliation(s)
- Yanju Ma
- School of Environmental Science & Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Chi-Yeung Choi
- School of Environmental Science & Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Alex Thomas
- School of Environmental Science & Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Luke Gibson
- School of Environmental Science & Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
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Ruskin KJ, Herring G, Eagles-Smith CA, Eiklor AB, Elphick CS, Etterson MA, Field CR, Longenecker RA, Kovach AI, Gregory Shriver W, Walsh J, Olsen BJ. Mercury exposure of tidal marsh songbirds in the northeastern United States and its association with nest survival. ECOTOXICOLOGY (LONDON, ENGLAND) 2022; 31:208-220. [PMID: 34783931 DOI: 10.1007/s10646-021-02488-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/25/2021] [Indexed: 06/13/2023]
Abstract
The biogeochemistry of tidal marsh sediments facilitates the transformation of mercury (Hg) into the biologically available form methylmercury (MeHg), resulting in elevated Hg exposures to tidal marsh wildlife. Saltmarsh and Acadian Nelson's sparrows (Ammospiza caudacutua and A. nelsoni subvirgatus, respectively) exclusively inhabit tidal marshes, potentially experiencing elevated risk to Hg exposure, and have experienced range-wide population declines. To characterize spatial and temporal variation of Hg exposure in these species, we sampled total mercury (THg) in blood collected from 9 populations spanning 560 km of coastline, including individuals resampled within and among years. Using concurrent nesting studies, we tested whether THg was correlated with nest survival probabilities, an index of fecundity. Blood THg ranged from 0.074-3.373 µg/g ww across 170 samples from 127 individuals. We detected high spatial variability in Hg exposure, observing differences of more than 45-fold across all individuals and 8-fold in mean blood THg among all study plots, including 4-fold between study plots within 4 km. Intraindividual changes in blood Hg exposure did not vary systematically in time but were considerable, varying by up to 2-fold within and among years. Controlling for both species differences and maximum water level, the dominant driver of fecundity in this system, nest survival probability decreased by 10% across the full range of female blood THg concentrations observed. We conclude that Hg has the potential to impair songbird reproduction, potentially exacerbating known climate-change driven population declines from sea-level rise in saltmarsh and Acadian Nelson's sparrows.
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Affiliation(s)
- Katharine J Ruskin
- Ecology and Environmental Sciences, 123 Bryand Global Sciences Center, University of Maine, Orono, ME, 04469, USA.
| | - Garth Herring
- United States Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR, 97331, USA
| | - Collin A Eagles-Smith
- United States Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR, 97331, USA
| | - Alyssa B Eiklor
- Vermont Department of Environmental Conservation, 1 National Life Dr Montpelier, Davis 1, VT, 05620-3520, USA
| | - Chris S Elphick
- Department of Ecology & Evolutionary Biology and Center of Biological Risk, University of Connecticut, 75 North Eagleville Road, U-43, Storrs, CT, 06269, USA
| | - Matthew A Etterson
- United States Environmental Protection Agency, Center for Computational Toxicology and Exposure, Great Lakes Toxicology and Ecology Division, 6201 Congdon Boulevard, Duluth, MN, 55804, USA
| | - Christopher R Field
- Department of Natural Resources Science, University of Rhode Island 45 Upper College Rd, Kingston, RI, 02881, USA
| | - Rebecca A Longenecker
- U.S. Fish and Wildlife Service, Northeast Regional Office, 300 Westgate Center Drive, Hadley, MA, 01035, USA
| | - Adrienne I Kovach
- Department of Natural Resources and the Environment, University of New Hampshire, 46 College Road, Durham, NH, 03824, USA
| | - W Gregory Shriver
- Department of Entomology and Wildlife Ecology, University of Delaware, 257 Townsend Hall, Newark, DE, 19716, USA
| | - Jennifer Walsh
- Cornell Lab of Ornithology, 159 Sapsucker Woods Road, Ithaca, NY, 14850, USA
| | - Brian J Olsen
- Ecology and Environmental Sciences, 123 Bryand Global Sciences Center, University of Maine, Orono, ME, 04469, USA
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8
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Smith RA, Yurkowski DJ, Parkinson KJL, Fort J, Hennin HL, Gilchrist HG, Hobson KA, Mallory ML, Danielsen J, Garbus SE, Hanssen SA, Jónsson JE, Latty CJ, Magnúsdóttir E, Moe B, Parsons GJ, Sonne C, Tertitski G, Love OP. Environmental and life-history factors influence inter-colony multidimensional niche metrics of a breeding Arctic marine bird. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 796:148935. [PMID: 34274678 DOI: 10.1016/j.scitotenv.2021.148935] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 07/05/2021] [Accepted: 07/05/2021] [Indexed: 06/13/2023]
Abstract
Human industrialization has resulted in rapid climate change, leading to wide-scale environmental shifts. These shifts can modify food web dynamics by altering the abundance and distribution of primary producers (ice algae and phytoplankton), as well as animals at higher trophic levels. Methylmercury (MeHg) is a neuro-endocrine disrupting compound which biomagnifies in animals as a function of prey choice, and as such bioavailability is affected by altered food web dynamics and adds an important risk-based dimension in studies of foraging ecology. Multidimensional niche dynamics (MDND; δ13C, δ15N, THg; total mercury) were determined among breeding common eider (Somateria mollissima) ducks sampled from 10 breeding colonies distributed across the circumpolar Arctic and subarctic. Results showed high variation in MDND among colonies as indicated by niche size and ranges in δ13C, δ15N and THg values in relation to spatial differences in primary production inferred from sea-ice presence and colony migratory status. Colonies with higher sea-ice cover during the pre-incubation period had higher median colony THg, δ15N, and δ13C. Individuals at migratory colonies had relatively higher THg and δ15N, and lower δ13C, suggesting a higher trophic position and a greater reliance on phytoplankton-based prey. It was concluded that variation in MDND exists among eider colonies which influenced individual blood THg concentrations. Further exploration of spatial ecotoxicology and MDND at each individual site is important to examine the relationships between anthropogenic activities, foraging behaviour, and the related risks of contaminant exposure at even low, sub-lethal concentrations that may contribute to deleterious effects on population stability over time. Overall, multidimensional niche analysis that incorporates multiple isotopic and contaminant metrics could help identify those populations at risk to rapidly altered food web dynamics.
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Affiliation(s)
- Reyd A Smith
- University of Windsor, Windsor, Ontario N9B 3P4, Canada.
| | | | | | - Jérôme Fort
- Littoral, Environnement et Sociétés (LIENSs), UMR 7266 CNRS - La Rochelle University, La Rochelle FR-17000, France
| | - Holly L Hennin
- Environment and Climate Change Canada, Ottawa, Ontario K0A 1H0, Canada
| | - H Grant Gilchrist
- Environment and Climate Change Canada, Ottawa, Ontario K0A 1H0, Canada
| | | | - Mark L Mallory
- cadia University, Wolfville, Nova Scotia B4P 2R6, Canada
| | | | | | | | - Jón Einar Jónsson
- University of Iceland's Research Centre at Snæfellsnes, Hafnargata 3, 340 Stykkishólmur, Iceland
| | - Christopher J Latty
- Arctic National Wildlife Refuge, U.S. Fish and Wildlife Service, Fairbanks, AK 99701, United States
| | - Ellen Magnúsdóttir
- University of Iceland's Research Centre at Snæfellsnes, Hafnargata 3, 340 Stykkishólmur, Iceland
| | - Børge Moe
- Norwegian Institute for Nature Research, Tromsø N-9296, Norway
| | - Glen J Parsons
- Nova Scotia Department of Lands and Forestry, Kentville, Nova Scotia B4N 4E5, Canada
| | | | - Grigori Tertitski
- Institute of Geography of the Russian Academy of Sciences, Moscow 119017, Russia
| | - Oliver P Love
- University of Windsor, Windsor, Ontario N9B 3P4, Canada
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9
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Gerson JR, Dorman R, Eagles-Smith C, Bernhardt ES, Walters D. Lethal impacts of selenium counterbalance the potential reduction in mercury bioaccumulation for freshwater organisms. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 287:117293. [PMID: 34030024 DOI: 10.1016/j.envpol.2021.117293] [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: 01/06/2021] [Revised: 04/27/2021] [Accepted: 04/29/2021] [Indexed: 06/12/2023]
Abstract
Mercury (Hg), a potent neurotoxic element, can biomagnify through food webs once converted into methylmercury (MeHg). Some studies have found that selenium (Se) exposure may reduce MeHg bioaccumulation and toxicity, though this pattern is not universal. Se itself can also be toxic at elevated levels. We experimentally manipulated the relative concentrations of dietary MeHg and Se (as selenomethionine [SeMet]) for an aquatic grazer (the mayfly, Neocloeon triangulifer) and its food source (diatoms). Under low MeHg treatment (0.2 ng/L), diatoms exhibited a quadratic pattern, with decreasing diatom MeHg concentration up to 2.0 μg Se/L and increasing MeHg accumulation at higher SeMet concentrations. Under high MeHg treatment (2 ng/L), SeMet concentrations had no effect on diatom MeHg concentrations. Mayfly MeHg concentrations and biomagnification factors (concentration of MeHg in mayflies: concentration of MeHg in diatoms) declined with SeMet addition only in the high MeHg treatment. Mayfly MeHg biomagnification factors decreased from 5.3 to 3.3 in the high MeHg treatment, while the biomagnification factor was constant with an average of 4.9 in the low MeHg treatment. The benefit of reduced MeHg biomagnification was offset by non-lethal effects and high mortality associated with 'protective' levels of SeMet exposure. Mayfly larvae escape behavior (i.e., startle response) was greatly reduced at early exposure days. Larvae took nearly twice as long to metamorphose to adults at high Se concentrations. The minimum number of days to mayfly emergence did not differ by SeMet exposure, with an average of 13 days. We measured an LC50SeMet for mayflies of 3.9 μg Se/L, with complete mortality at concentrations ≥6.0 μg Se/L. High reproductive mortality occurred at elevated SeMet exposures, with only 0-18% emergence at ≥4.12 μg Se/L. Collectively, our results suggest that while there is some evidence that Se can reduce MeHg accumulation at the base of the food web at specific exposure levels of SeMet and MeHg, Se is also toxic to mayflies and could lead to negative effects that extend across ecosystem boundaries.
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Affiliation(s)
| | - Rebecca Dorman
- U.S. Geological Survey, Columbia Environmental Research Center, Columbia, MO, 65201, USA
| | - Collin Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, OR, 97330, USA
| | | | - David Walters
- U.S. Geological Survey, Columbia Environmental Research Center, Columbia, MO, 65201, USA
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10
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Ma Y, Hobson KA, Kardynal KJ, Guglielmo CG, Branfireun BA. Inferring spatial patterns of mercury exposure in migratory boreal songbirds: Combining feather mercury and stable isotope (δ 2H) measurements. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 762:143109. [PMID: 33162143 DOI: 10.1016/j.scitotenv.2020.143109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 06/11/2023]
Abstract
Migratory songbirds breeding in the Canadian Boreal forest are exposed to mercury (Hg), a potent neurotoxin that impairs avian health, however, the degree of exposure depends on many factors. As breeding grounds are geographically remote and vast, the measurement of Hg in individual birds is impractical particularly at large spatial scales. Here, we present a Canada-wide dataset of nearly 2000 migratory songbirds that were used to assess summer Hg exposure of 15 songbird species sampled during fall migration. We measured Hg concentrations in tail feathers and related those to dietary guild, geographic capture location, age, sex and probable breeding ground locations using feather δ2H. Overall mean (±SE) feather Hg concentration was 1.49 ± 0.03 μg/g (N = 1946): however, a clear geographic gradient in feather Hg concentrations emerged being highest in East and lowest in West. Dietary guild was the next strongest predictor of feather Hg with insectivorous songbirds in Eastern Canada at particular risk due to Hg exposure on summer breeding grounds. This broad-scale assessment of Hg exposure in migratory songbirds in Canada can be used to guide future studies on finer-scale determinants of Hg exposure in birds.
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Affiliation(s)
- Yanju Ma
- Department of Biology, University of Western Ontario, London, Ontario, Canada; Advanced Facility for Avian Research, University of Western Ontario, London, Ontario, Canada
| | - Keith A Hobson
- Department of Biology, University of Western Ontario, London, Ontario, Canada; Science and Technology Branch, Environment and Climate Change Canada, Saskatoon, Saskatchewan, Canada
| | - Kevin J Kardynal
- Science and Technology Branch, Environment and Climate Change Canada, Saskatoon, Saskatchewan, Canada
| | - Christopher G Guglielmo
- Department of Biology, University of Western Ontario, London, Ontario, Canada; Advanced Facility for Avian Research, University of Western Ontario, London, Ontario, Canada
| | - Brian A Branfireun
- Department of Biology, University of Western Ontario, London, Ontario, Canada; Centre for Environment and Sustainability, University of Western Ontario, London, Ontario, Canada.
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11
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Cristol DA, Evers DC. The impact of mercury on North American songbirds: effects, trends, and predictive factors. ECOTOXICOLOGY (LONDON, ENGLAND) 2020; 29:1107-1116. [PMID: 32970279 DOI: 10.1007/s10646-020-02280-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/10/2020] [Indexed: 06/11/2023]
Abstract
Researchers were asked to contribute new results addressing questions about the exposure and effects of mercury (Hg) in North American songbirds, a rapidly declining group of species that is the subject of enduring interest for millions of birdwatchers, the general public and conservation scientists. Important questions to be answered include: Is Hg causing or exacerbating songbird population declines? Which North American songbirds are at most risk and in which landscapes? Are there aspects of songbird natural history that pre-dispose them to risks of Hg exposure and effects, in particular, their migratory behavior? In all, 61 authors contributed 15 studies addressing aspects of these questions. Articles in this special issue address an array of topics including: (1) three studies on health effects in the laboratory using a domesticated songbird model species, the zebra finch; (2) three studies on changes in songbird exposure to Hg over time spans from less than a decade to more than a century; (3) five studies on landscape characteristics or management practices that cause the oft-noted spatial variation in Hg accumulation by resident songbirds, from the subarctic tundra to high-elevation tropical forests; (4) three papers examining the recently recognized role of migration behavior in predicting risk to songbirds from Hg; and (5) one paper on the potential pitfalls of using feather Hg concentration as a bioindicator for Hg exposure. In summary, although there are many questions still to be answered, it is clear that the effects of Hg are persistent long after exposure, Hg exposure of North American songbirds is not improving, predicting exposure requires a detailed understanding of ecosystem processes beyond simply the amount of Hg present at a site, migration behavior predisposes songbirds to risk of Hg exposure and effects, and carefully selecting appropriate bioindicator sites, species, and tissues is critical to any monitoring efforts.
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Affiliation(s)
- Daniel A Cristol
- Department of Biology, William & Mary, PO Box 8795, Williamsburg, VA, 23187-8795, USA.
| | - David C Evers
- Biodiversity Research Institute, 276 Canco Drive, Portland, ME, 04105, USA
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12
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Kardynal KJ, Jardine TD, Génier CSV, Bumelis KH, Mitchell GW, Evans M, Hobson KA. Mercury exposure to swallows breeding in Canada inferred from feathers grown on breeding and non-breeding grounds. ECOTOXICOLOGY (LONDON, ENGLAND) 2020; 29:876-891. [PMID: 32656653 DOI: 10.1007/s10646-020-02249-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/30/2020] [Indexed: 06/11/2023]
Abstract
Aerial insectivorous birds such as swallows have been the steepest declining groups of birds in North America over the last 50 years but whether such declines are linked to contaminants has not been examined. We sampled feathers from five species of swallow at multiple locations to assess total mercury [THg] exposure for adults during the non-breeding season, and for juveniles on the breeding grounds. We assessed Hg exposure to juvenile birds in crop- and grass-dominated landscapes to determine if land-use practices influenced feather [THg]. We assayed feathers for stable isotopes (δ2H, δ13C, δ15N) as proxies for relative habitat use and diet to determine their potential influence on feather [THg]. Feather [THg] was highest in adult bank swallows (Riparia riparia) and purple martins (Progne subis) from Saskatchewan and adult cliff swallows (Petrochelidon pyrrhonota) from western regions, indicating differential exposure to Hg on the non-breeding grounds. Juvenile bank, barn (Hirundo rustica) and tree (Tachycineta bicolor) swallows had lower feather [THg] in crop-dominated landscapes than grass-dominated landscapes in Saskatchewan, potentially resulting from lower use of wetland-derived insects due to wetland drainage and intensive agriculture. Feather [THg] was related to juvenile feather stable isotopes for several species, suggesting complex interactions with diet and environmental factors. Many individuals had feather [THg] values >2 µg/g, a threshold at which deleterious effects may occur. Our findings indicate differential Hg exposure among species of swallow, regions and land-uses and highlight the need for additional research to determine dietary and finer-scale land-use impacts on individual species and populations.
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Affiliation(s)
- Kevin J Kardynal
- Environment and Climate Change Canada, 11 Innovation Blvd., Saskatoon, SK, S7N 3H5, Canada.
| | - Timothy D Jardine
- School of Environment and Sustainability, Toxicology Centre, University of Saskatchewan, Saskatoon, SK, S7N 5B3, Canada
| | - Corrine S V Génier
- Department of Biology, University of Western Ontario, London, ON, N6A 3K7, Canada
| | - Kaelyn H Bumelis
- Department of Biology, University of Western Ontario, London, ON, N6A 3K7, Canada
| | - Greg W Mitchell
- Environment and Climate Change Canada, 1125 Colonel By Drive, Ottawa, ON, K1A 0H3, Canada
| | - Marlene Evans
- Environment and Climate Change Canada, 11 Innovation Blvd., Saskatoon, SK, S7N 3H5, Canada
| | - Keith A Hobson
- Environment and Climate Change Canada, 11 Innovation Blvd., Saskatoon, SK, S7N 3H5, Canada
- Department of Biology, University of Western Ontario, London, ON, N6A 3K7, Canada
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13
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Canadian Arctic Contaminants and Their Effects on the Maternal Brain and Behaviour: A Scoping Review of the Animal Literature. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17030926. [PMID: 32024308 PMCID: PMC7038163 DOI: 10.3390/ijerph17030926] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 01/30/2020] [Accepted: 01/31/2020] [Indexed: 12/15/2022]
Abstract
Background: Environmental toxicants such as methylmercury, polychlorinated biphenyls, and organochlorine pesticides are potentially harmful pollutants present in contaminated food, soil, air, and water. Exposure to these ecologically relevant toxicants is prominent in Northern Canadian populations. Previous work focused on toxicant exposure during pregnancy as a threat to fetal neurodevelopment. However, little is known about the individual and combined effects of these toxicants on maternal health during pregnancy and post-partum. Methods: A scoping review was conducted to synthesize the current knowledge regarding individual and combined effects of methylmercury, polychlorinated biphenyls, and organochlorine pesticides on maternal behaviour and the maternal brain. Relevant studies were identified through the PubMed, Embase, and Toxline databases. Literature involving animal models and one human cohort were included in the review. Results: Research findings indicate that exposures to these environmental toxicants are associated with neurochemical changes in rodent models. Animal models provided the majority of information on toxicant-induced alterations in maternal care behaviours. Molecular and hormonal changes hypothesized to underlie these alterations were also addressed, although studies assessing toxicant co-exposure were limited. Conclusion: This review speaks to the limited knowledge regarding effects of these persistent organic pollutants on the maternal brain and related behavioural outcomes. Further research is required to better comprehend any such effects on maternal brain and behaviour, as maternal care is an important contributor to offspring neurodevelopment.
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14
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Mathew M, Aravindakumar CT, Aravind UK. Unravelling the fibrillation mechanism of ovalbumin in the presence of mercury at its isoelectric pH. RSC Adv 2020; 10:16415-16421. [PMID: 35498851 PMCID: PMC9052921 DOI: 10.1039/c9ra10655c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/03/2020] [Indexed: 02/03/2023] Open
Abstract
The intriguing resemblances of amyloid fibrils and spider silk in protein aggregation diseases have instigated the exploration of identical structural features if any in their oligomeric pathways. The serpin group protein, ovalbumin, on defolding in HgCl2 shares commonness to the micellar pathway of spidroins for their aggregation in response to a pH trigger. The structural feature changes from monomer to worm like fibril with a shift in the primary protein pH to slightly acidic pH (4.5), and then proceeds through a secondary nucleation pathway to ‘hillock’ and ‘hydra’ like protofibrils rich in β-sheet and random coil conformers upon exposure to mercury. The findings are backed by atomic force microscopy, confocal Raman spectroscopy and fluorescence measurements. Unlocking such structural features can favorably assist in the design of therapeutics. Mercuric chloride triggered ovalbumin aggregation pathway and its resemblance to Nephila clavipes.![]()
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Affiliation(s)
- Manjumol Mathew
- Advanced Centre of Environmental Studies and Sustainable Development
- Mahatma Gandhi University
- Kottayam-686 560
- India
| | - Charuvila T. Aravindakumar
- School of Environmental Sciences
- Inter University Instrumentation Centre
- Mahatma Gandhi University
- Kottayam-686 560
- India
| | - Usha K. Aravind
- School of Environmental Studies
- Cochin University of Science and Technology
- Kochi-682022
- India
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