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O'Hara TM, Ylitalo GM, Crawford SG, Taras BD, Fadely BS, Rehberg MJ, Rea LD. Spatial and cumulative organochlorine and mercury exposure assessments in Steller Sea lions of Alaska: Emphasizing pups. MARINE POLLUTION BULLETIN 2024; 205:116592. [PMID: 38917493 DOI: 10.1016/j.marpolbul.2024.116592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 06/08/2024] [Accepted: 06/10/2024] [Indexed: 06/27/2024]
Abstract
Steller sea lions (SSL) are sentinels for monitoring environmental contaminants in remote areas of the Aleutian Islands, Alaska. Therefore, concentrations of several organochlorines (OCs) were measured in blood from 123 SSL pups sampled from 3 regions; the western Aleutian Islands (WAI), central Aleutian Islands (CAI), and the central Gulf of Alaska. Blood, blubber, and milk from 12 adult female SSL from WAI, CAI and southeast Alaska also were analyzed. Findings included the following. SSL pups had higher concentrations of some OCs and mercury (Hg) on rookeries in the WAI than those more easterly. Pups had significantly higher blood concentrations of many OC classes than adult females sampled within the same region; some pups had PCB concentrations exceeding thresholds of concern (∑PCBs >8600 ng/g lw). ∑PCB concentration in pup whole blood was positively correlated with the trophic marker, δ15N within the regions sampled, along with two PCB congeners (PCB138 and PCB153). This suggests that the dams of pups with higher ∑PCBs, PCB138, and PCB153 concentrations were feeding on more predatory prey. Adult female blubber ∑DDT and hexachlorocyclohexane concentrations were also positively correlated with δ15N values. Several pups (mostly from WAI) had blood Hg concentrations and/or blood PCB concentrations (surrogate for overall OC exposures) of concern. The finding that WAI SSL pups have been exposed to multiple contaminants calls for future investigation of their cumulative exposure to a mixture of contaminants especially their transplacental and then transmammary exposure routes.
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Affiliation(s)
- T M O'Hara
- Department of Veterinary Medicine, College of Natural Sciences and Mathematics, University of Alaska Fairbanks, Fairbanks, AK 99775, USA; Veterinary Integrative Biosciences, School of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA; Institute of Northern Engineering, Water and Environmental Research Center, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - G M Ylitalo
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Blvd. East, Seattle, WA 98112, USA
| | - S G Crawford
- Institute of Northern Engineering, Water and Environmental Research Center, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - B D Taras
- Alaska Department of Fish and Game, Division of Wildlife Conservation, Fairbanks, AK 99701, USA
| | - B S Fadely
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, WA 98115, USA
| | - M J Rehberg
- Alaska Department of Fish and Game, Division of Wildlife Conservation, Anchorage, AK 99518, USA
| | - L D Rea
- Institute of Northern Engineering, Water and Environmental Research Center, University of Alaska Fairbanks, Fairbanks, AK 99775, USA; Alaska Department of Fish and Game, Division of Wildlife Conservation, Fairbanks, AK 99701, USA.
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Fuchs B, Joly K, Hilderbrand GV, Evans AL, Rodushkin I, Mangipane LS, Mangipane BA, Gustine DD, Zedrosser A, Brown L, Arnemo JM. Toxic elements in arctic and sub-arctic brown bears: Blood concentrations of As, Cd, Hg and Pb in relation to diet, age, and human footprint. ENVIRONMENTAL RESEARCH 2023; 229:115952. [PMID: 37116674 DOI: 10.1016/j.envres.2023.115952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/16/2023] [Accepted: 04/18/2023] [Indexed: 05/07/2023]
Abstract
Contamination with arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb) is a global concern impairing resilience of organisms and ecosystems. Proximity to emission sources increases exposure risk but remoteness does not alleviate it. These toxic elements are transported in atmospheric and oceanic pathways and accumulate in organisms. Mercury accumulates in higher trophic levels. Brown bears (Ursus arctos), which often live in remote areas, are long-lived omnivores, feeding on salmon (Oncorhynchus spp.) and berries (Vaccinium spp.), resources also consumed by humans. We measured blood concentrations of As, Cd, Hg and Pb in bears (n = 72) four years and older in Scandinavia and three national parks in Alaska, USA (Lake Clark, Katmai and Gates of the Arctic) using high-resolution, inductively-coupled plasma sector field mass spectrometry. Age and sex of the bears, as well as the typical population level diet was associated with blood element concentrations using generalized linear regression models. Alaskan bears consuming salmon had higher Hg blood concentrations compared to Scandinavian bears feeding on berries, ants (Formica spp.) and moose (Alces). Cadmium and Pb blood concentrations were higher in Scandinavian bears than in Alaskan bears. Bears using marine food sources, in addition to salmon in Katmai, had higher As blood concentrations than bears in Scandinavia. Blood concentrations of Cd and Pb, as well as for As in female bears increased with age. Arsenic in males and Hg concentrations decreased with age. We detected elevated levels of toxic elements in bears from landscapes that are among the most pristine on the planet. Sources are unknown but anthropogenic emissions are most likely involved. All study areas face upcoming change: Increasing tourism and mining in Alaska and more intensive forestry in Scandinavia, combined with global climate change in both regions. Baseline contaminant concentrations as presented here are important knowledge in our changing world.
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Affiliation(s)
- Boris Fuchs
- Department of Forestry and Wildlife Management, Inland Norway University of Applied Sciences, Campus Evenstad, 2480, Koppang, Norway.
| | - Kyle Joly
- National Park Service, Gates of the Arctic National Park and Preserve, 99709, Fairbanks, Alaska, USA.
| | - Grant V Hilderbrand
- National Park Service, Alaska Regional Office, 99501, Anchorage, Alaska, USA
| | - Alina L Evans
- Department of Forestry and Wildlife Management, Inland Norway University of Applied Sciences, Campus Evenstad, 2480, Koppang, Norway
| | - Ilia Rodushkin
- Division of Geosciences, Luleå University of Technology, 97187, Luleå, Sweden; ALS Scandinavia AB, 97187, Luleå, Sweden
| | - Lindsey S Mangipane
- U.S. Fish and Wildlife Service, Marine Mammals Management, 99503, Anchorage, Alaska, USA
| | - Buck A Mangipane
- Lake Clark National Park and Preserve, National Park Service, 99501, Anchorage, Alaska, USA
| | - David D Gustine
- U.S. Fish and Wildlife Service, Marine Mammals Management, 99503, Anchorage, Alaska, USA
| | - Andreas Zedrosser
- Department of Natural Science and Environmental Health, University of South-Eastern Norway, 3800, Bø in Telemark, Norway; Institute for Wildlife Biology and Game Management, University of Natural Resources and Life Sciences, 1180, Vienna, Austria
| | - Ludovick Brown
- Département de Biologie, Université de Sherbrooke, J1K 2R1, Sherbrooke, Québec, Canada
| | - Jon M Arnemo
- Department of Forestry and Wildlife Management, Inland Norway University of Applied Sciences, Campus Evenstad, 2480, Koppang, Norway; Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
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Rea LD, Castellini JM, Avery JP, Fadely BS, Burkanov VN, Rehberg MJ, O'Hara TM. Regional variations and drivers of mercury and selenium concentrations in Steller sea lions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 744:140787. [PMID: 32717470 DOI: 10.1016/j.scitotenv.2020.140787] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 07/01/2020] [Accepted: 07/04/2020] [Indexed: 06/11/2023]
Abstract
Mercury (Hg) can be neurotoxic to mammals and impact reproduction, whereas selenium (Se) is an important antioxidant known to ameliorate some adverse effects of Hg. Total Hg concentrations ([THg]) were measured in lanugo (pelage grown in utero) of 812 Steller sea lion (Eumetopias jubatus) pups across Alaska and Russia to assess fetal exposure during late gestation. The molar ratio of total Se to THg (TSe:THg) was determined in whole blood collected from 291 pups. Stable isotope ratios of carbon and nitrogen were measured in sections of vibrissae (whiskers, n = 498) and in lanugo (n = 480) of pups grown during late gestation to track diet variations among adult females that can drive Hg and Se exposure during this critical fetal development period. Lanugo [THg] ranged from 1.4 to 73.7 μg/g dry weight with the lowest median [THg] in Southeast Alaska. Pups from the Western Aleutian Islands had higher median lanugo [THg] than pups from other metapopulations in Alaska. Over 25% of pups in the Western Aleutian Islands had [THg] above published risk thresholds (20 μg/g) for other mammals. Whole blood molar TSe:THg was significantly lower in the Western Aleutian Islands and in some parts of the Central Aleutian Islands with higher molar ratios found in the Eastern Aleutian Islands and Central Gulf of Alaska. This suggests a limitation on potential protective functions of Se in the western regions with the highest relative [THg]. The Central Aleutian Island pups with [THg] over 20 μg/g had higher δ15N ratios than pups with lower [THg] suggesting dams consuming higher trophic level prey is a key driver for Hg exposure. However, regional differences likely reflect variability in diet of the dam during gestation and in Hg food web dynamics between oceanic regimes east and west of key passes in the Aleutian Islands.
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Affiliation(s)
- L D Rea
- Institute of Northern Engineering, Water and Environmental Research Center, University of Alaska Fairbanks, Fairbanks, AK 99775, USA; Alaska Department of Fish and Game, Division of Wildlife Conservation, Anchorage, AK 99518, USA.
| | - J M Castellini
- Department of Veterinary Medicine, College of Natural Sciences and Mathematics, University of Alaska Fairbanks, Fairbanks, AK 99775, USA.
| | - J P Avery
- Institute of Northern Engineering, Water and Environmental Research Center, University of Alaska Fairbanks, Fairbanks, AK 99775, USA.
| | - B S Fadely
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, WA 98115, USA.
| | - V N Burkanov
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, WA 98115, USA; Kamchatka Branch of the Pacific Geographical Institute, Far East Branch of Russian Academy of Sciences, 6 Partizanskaya Street, Petropavlovsk-Kamchatsky 683000, Russia.
| | - M J Rehberg
- Alaska Department of Fish and Game, Division of Wildlife Conservation, Anchorage, AK 99518, USA.
| | - T M O'Hara
- Department of Veterinary Medicine, College of Natural Sciences and Mathematics, University of Alaska Fairbanks, Fairbanks, AK 99775, USA; Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA.
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HAIR, WHOLE BLOOD, AND BLOOD-SOAKED CELLULOSE PAPER-BASED RISK ASSESSMENT OF MERCURY CONCENTRATIONS IN STRANDED CALIFORNIA PINNIPEDS. J Wildl Dis 2019. [DOI: 10.7589/2018-11-276] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Routti H, Atwood TC, Bechshoft T, Boltunov A, Ciesielski TM, Desforges JP, Dietz R, Gabrielsen GW, Jenssen BM, Letcher RJ, McKinney MA, Morris AD, Rigét FF, Sonne C, Styrishave B, Tartu S. State of knowledge on current exposure, fate and potential health effects of contaminants in polar bears from the circumpolar Arctic. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 664:1063-1083. [PMID: 30901781 DOI: 10.1016/j.scitotenv.2019.02.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/01/2019] [Accepted: 02/02/2019] [Indexed: 05/03/2023]
Abstract
The polar bear (Ursus maritimus) is among the Arctic species exposed to the highest concentrations of long-range transported bioaccumulative contaminants, such as halogenated organic compounds and mercury. Contaminant exposure is considered to be one of the largest threats to polar bears after the loss of their Arctic sea ice habitat due to climate change. The aim of this review is to provide a comprehensive summary of current exposure, fate, and potential health effects of contaminants in polar bears from the circumpolar Arctic required by the Circumpolar Action Plan for polar bear conservation. Overall results suggest that legacy persistent organic pollutants (POPs) including polychlorinated biphenyls, chlordanes and perfluorooctane sulfonic acid (PFOS), followed by other perfluoroalkyl compounds (e.g. carboxylic acids, PFCAs) and brominated flame retardants, are still the main compounds in polar bears. Concentrations of several legacy POPs that have been banned for decades in most parts of the world have generally declined in polar bears. Current spatial trends of contaminants vary widely between compounds and recent studies suggest increased concentrations of both POPs and PFCAs in certain subpopulations. Correlative field studies, supported by in vitro studies, suggest that contaminant exposure disrupts circulating levels of thyroid hormones and lipid metabolism, and alters neurochemistry in polar bears. Additionally, field and in vitro studies and risk assessments indicate the potential for adverse impacts to polar bear immune functions from exposure to certain contaminants.
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Affiliation(s)
- Heli Routti
- Norwegian Polar Institute, Fram Centre, NO-9296 Tromsø, Norway.
| | - Todd C Atwood
- U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK 99508, USA
| | - Thea Bechshoft
- Department of Bioscience, Arctic Research Centre (ARC), Faculty of Science and Technology, Aarhus University, Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark
| | - Andrei Boltunov
- Marine Mammal Research and Expedition Center, 36 Nahimovskiy pr., Moscow 117997, Russia
| | - Tomasz M Ciesielski
- Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Jean-Pierre Desforges
- Department of Bioscience, Arctic Research Centre (ARC), Faculty of Science and Technology, Aarhus University, Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark
| | - Rune Dietz
- Department of Bioscience, Arctic Research Centre (ARC), Faculty of Science and Technology, Aarhus University, Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark
| | | | - Bjørn M Jenssen
- Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; Department of Bioscience, Arctic Research Centre (ARC), Faculty of Science and Technology, Aarhus University, Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark; Department of Arctic Technology, University Centre in Svalbard, PO Box 156, NO-9171 Longyearbyen, Norway
| | - Robert J Letcher
- Ecotoxicology and Wildlife Heath Division, Wildlife and Landscape Science Directorate, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, 1125 Colonel By Dr., Ottawa, Ontario K1A 0H3, Canada
| | - Melissa A McKinney
- Department of Natural Resource Sciences, McGill University, Ste.-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - Adam D Morris
- Ecotoxicology and Wildlife Heath Division, Wildlife and Landscape Science Directorate, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, 1125 Colonel By Dr., Ottawa, Ontario K1A 0H3, Canada
| | - Frank F Rigét
- Department of Bioscience, Arctic Research Centre (ARC), Faculty of Science and Technology, Aarhus University, Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark
| | - Christian Sonne
- Department of Bioscience, Arctic Research Centre (ARC), Faculty of Science and Technology, Aarhus University, Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark
| | - Bjarne Styrishave
- Toxicology and Drug Metabolism Group, Department of Pharmacy, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen OE, Denmark
| | - Sabrina Tartu
- Norwegian Polar Institute, Fram Centre, NO-9296 Tromsø, Norway
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Pedro S, Boba C, Dietz R, Sonne C, Rosing-Asvid A, Hansen M, Provatas A, McKinney MA. Blubber-depth distribution and bioaccumulation of PCBs and organochlorine pesticides in Arctic-invading killer whales. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 601-602:237-246. [PMID: 28554115 DOI: 10.1016/j.scitotenv.2017.05.193] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 05/19/2017] [Accepted: 05/20/2017] [Indexed: 06/07/2023]
Abstract
Sightings of killer whales (Orcinus orca) in Greenland have increased in recent years, coincident with sea ice loss. These killer whales are likely from fish-feeding North Atlantic populations, but may have access to marine mammal prey in Greenlandic waters, which could lead to increased exposures to biomagnifying contaminants. Most studies on polychlorinated biphenyl (PCB) and organochlorine (OC) contaminants in killer whales have used biopsies which may not be representative of contaminant concentrations through the entire blubber depth. Here, we measured PCB and OC concentrations in 10 equal-length blubber sections of 18 killer whales harvested in southeast Greenland (2012-2014), and 3 stranded in the Faroe Islands (2008) and Denmark (2005). Overall, very high concentrations of ΣPCB, Σchlordanes (ΣCHL), and Σdichlorodiphenyltrichloroethane (ΣDDT) were found in the southeast Greenland and Denmark individuals (means of ~40 to 70mgkg-1 lipid weight). These concentrations were higher than in the Faroe Island individuals (means of ~2 to 5mgkg-1 lipid weight) and above those previously reported for other fish-feeding killer whales in the North Atlantic, likely in part due to additional feeding on marine mammals. On a wet weight basis, concentrations of all contaminants were significantly lower in the outermost blubber layer (0.15-0.65cm) compared to all other layers (p<0.01), except for Σhexachlorocyclohexanes. However, after lipid correction, no variation was found for ΣCHL and Σchlorobenzene concentrations, while the outermost layer(s) still showed significantly lower ΣPCB, ΣDDT, Σmirex, Σendosulfan, and dieldrin concentrations than one or more of the inner layers. Yet, the magnitude of these differences was low (up to 2-fold) suggesting that a typical biopsy may be a reasonable representation of the PCB and OC concentrations reported in killer whales, at least on a lipid weight basis.
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Affiliation(s)
- Sara Pedro
- Wildlife and Fisheries Conservation Center, Department of Natural Resources and the Environment and Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, CT 06269, USA.
| | - Conor Boba
- Wildlife and Fisheries Conservation Center, Department of Natural Resources and the Environment and Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, CT 06269, USA
| | - Rune Dietz
- Department of Bioscience, Arctic Research Centre, Aarhus University, Roskilde DK-4000, Denmark
| | - Christian Sonne
- Department of Bioscience, Arctic Research Centre, Aarhus University, Roskilde DK-4000, Denmark
| | | | - Martin Hansen
- Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720, USA; Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
| | - Anthony Provatas
- Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, CT 06269, USA
| | - Melissa A McKinney
- Wildlife and Fisheries Conservation Center, Department of Natural Resources and the Environment and Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, CT 06269, USA
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McKinney MA, Atwood TC, Pedro S, Peacock E. Ecological Change Drives a Decline in Mercury Concentrations in Southern Beaufort Sea Polar Bears. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:7814-7822. [PMID: 28612610 DOI: 10.1021/acs.est.7b00812] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We evaluated total mercury (THg) concentrations and trends in polar bears from the southern Beaufort Sea subpopulation from 2004 to 2011. Hair THg concentrations ranged widely among individuals from 0.6 to 13.3 μg g-1 dry weight (mean: 3.5 ± 0.2 μg g-1). Concentrations differed among sex and age classes: solitary adult females ≈ adult females with cubs ≈ subadults > adult males ≈ yearlings > cubs-of-the-year ≈ 2 year old dependent cubs. No variation was observed between spring and fall samples. For spring-sampled adults, THg concentrations declined by 13% per year, contrasting recent trends observed for other Western Hemispheric Arctic biota. Concentrations also declined by 15% per year considering adult males only, while a slower, nonsignificant decrease of 4.4% per year was found for adult females. Lower THg concentrations were associated with higher body mass index (BMI) and higher proportions of lower trophic position food resources consumed. Because BMI and diet were related, and the relationship to THg was strongest for BMI, trends were re-evaluated adjusting for BMI as the covariate. The adjusted annual decline was not significant. These findings indicate that changes in foraging ecology, not declining environmental concentrations of mercury, are driving short-term declines in THg concentrations in southern Beaufort Sea polar bears.
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Affiliation(s)
- Melissa A McKinney
- Wildlife and Fisheries Conservation Center, Department of Natural Resources and the Environment and Center for Environmental Sciences and Engineering, University of Connecticut , Storrs, Connecticut 06269, United States
| | - Todd C Atwood
- United States Geological Survey, Alaska Science Center , Anchorage, Alaska 99508, United States
| | - Sara Pedro
- Wildlife and Fisheries Conservation Center, Department of Natural Resources and the Environment and Center for Environmental Sciences and Engineering, University of Connecticut , Storrs, Connecticut 06269, United States
| | - Elizabeth Peacock
- United States Geological Survey, Alaska Science Center , Anchorage, Alaska 99508, United States
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Cyr A, Sergeant CJ, Lopez JA, O'Hara T. Assessing the influence of migration barriers and feeding ecology on total mercury concentrations in Dolly Varden (Salvelinus malma) from a glaciated and non-glaciated stream. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 580:710-718. [PMID: 27979620 DOI: 10.1016/j.scitotenv.2016.12.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/02/2016] [Accepted: 12/02/2016] [Indexed: 06/06/2023]
Abstract
Assimilation of mercury (Hg) into food webs is directly influenced by ecological factors such as local habitat characteristics, species feeding behavior, and movement patterns. Total Hg concentrations ([THg]) in biota from Subarctic latitudes are driven both by broad spatial processes such as long-range atmospheric transport and more local influences such as biovectors and geology. Thus, even relatively pristine protected lands such as national parks are experiencing Hg accumulation. We analyzed [THg] and stable isotopes of carbon (δ13C) and nitrogen (δ15N) in 104 Dolly Varden (Salvelinus malma) collected from two rivers in southeastern Alaska, upstream and downstream of apparent anadromous migration barriers in watersheds with and without glacial coverage. To assess the potential magnitude of marine-derived THg returning to freshwater, we analyzed [THg] in ten adult pink salmon from each study system. There were no differences in Dolly Varden mean [THg] between sites after the data were standardized for fork length, but unadjusted [THg] varied relative to fish size and δ15N values. While previous studies generally show that [THg] increases with higher δ15N values, we found that Dolly Varden below migration barriers and foraging on salmon eggs had the highest δ15N values among all sampled individuals, but the lowest [THg]. Dolly Varden residing below anadromous barriers had δ13C values consistent with marine influence. Since salmon eggs typically have low [Hg], our results suggest that abundant salmon populations and the dietary subsidy they provide may reduce the annual exposure to [Hg] in egg-eating stream fishes such as Dolly Varden. In addition to identifying a suitable species for freshwater Hg monitoring in southeastern Alaska, our study more broadly implies that river characteristics, location within a river, fish size, and feeding ecology are important factors influencing Hg accumulation.
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Affiliation(s)
- Andrew Cyr
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 905 N Koyukuk Dr, Fairbanks, AK 99775-7220, USA.
| | - Christopher J Sergeant
- National Park Service, Inventory and Monitoring Program, 3100 National Park Road, Juneau 99801, AK, USA
| | - Juan Andres Lopez
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 905 N Koyukuk Dr, Fairbanks, AK 99775-7220, USA; University of Alaska Museum of the North, University of Alaska Fairbanks, 907 Yukon Dr, Fairbanks, AK 99775-6960, USA
| | - Todd O'Hara
- Department of Veterinary Medicine, University of Alaska Fairbanks, 901 Koyukuk Dr, Fairbanks, AK 99775-7750, USA
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Bechshoft T, Derocher AE, Richardson E, Mislan P, Lunn NJ, Sonne C, Dietz R, Janz DM, St Louis VL. Mercury and cortisol in Western Hudson Bay polar bear hair. ECOTOXICOLOGY (LONDON, ENGLAND) 2015; 24:1315-1321. [PMID: 26044932 DOI: 10.1007/s10646-015-1506-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/30/2015] [Indexed: 06/04/2023]
Abstract
Non-invasive methods of assessing animal health and life history are becoming increasingly popular in wildlife research; hair samples from polar bears (Ursus maritimus), are being used to study an ever broader range of anthropogenic and endocrine compounds. A number of contaminants are known to disrupt endocrine function in polar bears. However, the relationship between mercury and cortisol remains unknown, although mercury is an endocrine disruptor in other species. Here, we examine the relationship between concentrations of cortisol and total mercury (THg) analyzed in guard hair from 378 polar bears (184 females, 194 males) sampled in Western Hudson Bay, 2004-2012. The difference in mean cortisol concentration between female (0.8 ± 0.6 pg/mg) and male (0.7 ± 0.5 pg/mg) polar bears bordered on significance (p = 0.054). However, mean mercury concentration was significantly greater (p = 0.009) in females (4.7 ± 1.4 μg/g) than males (4.3 ± 1.2 μg/g). Hair cortisol in males was significantly influenced by mercury, age, and fatness, as well as interactions between mercury and year, mercury and fatness, and year and fatness (all: p < 0.03) (multiple regression analysis, whole model: r(2) = 0.14, F(7,185) = 4.43, p = 0.0001). Fatness was the only significant variable in the multiple regression analysis for females (r(2) = 0.06, F(1,182) = 13.0, p = 0.0004). In conclusion, a significant, but complex, relationship was found between mercury and cortisol concentrations in hair from male, but not female, polar bears.
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Affiliation(s)
- T Bechshoft
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada,
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Dainowski BH, Duffy LK, McIntyre J, Jones P. Hair and bone as predictors of tissular mercury concentration in the western Alaska red fox, Vulpes vulpes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 518-519:526-33. [PMID: 25777958 PMCID: PMC4404022 DOI: 10.1016/j.scitotenv.2015.03.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 03/03/2015] [Accepted: 03/03/2015] [Indexed: 05/11/2023]
Abstract
We evaluated if total mercury (THg) concentrations of keratin-based and bone-based tissues can predict THg concentrations in skeletal muscle, renal medulla, renal cortex, and liver. The THg concentration in matched tissues of 65 red foxes, Vulpes vulpes, from western Alaska was determined. Hair THg concentration had a significant positive correlation with liver, renal medulla, renal cortex, and muscle. The THg concentration for males and females is moderately predictive of THg concentration in the renal cortex and liver for these foxes based on R(2) values (R(2)=0.61 and 0.63, respectively). Bone is weakly predictive of THg concentration in muscle (R(2)=0.40), but not a reliable tissue to predict THg concentration in liver (R(2)=0.24), renal cortex (R(2)=0.35), or renal medulla (R(2)=0.25). These results confirm the potential use of trapped animals, specifically foxes, as useful Arctic sentinel species to inform researchers about patterns in THg levels over time as industrialization of the Arctic continues.
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Affiliation(s)
- B H Dainowski
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, United States; Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK 99775, United States.
| | - L K Duffy
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, United States; Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK 99775, United States.
| | - J McIntyre
- Department of Mathematics and Statistics, University of Alaska Fairbanks, Fairbanks, AK 99775, United States.
| | - P Jones
- Alaksa Department of Fish and Game, Bethel, AK 99559, United States
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Marine diet and tobacco exposure affects mercury concentrations in pregnant women (I) from Baja California Sur, Mexico. Toxicol Rep 2014; 1:1123-1132. [PMID: 28203532 PMCID: PMC5304913 DOI: 10.1016/j.toxrep.2014.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Seafood provides essential polyunsaturated fatty acids (PUFA) and other nutrients to pregnant women and their fetus(es) while a diet rich in finfish can be a major pathway of monomethyl mercury (MeHg+) exposure. We measured total mercury concentration ([THg]) in hair samples provided by 75 women in Baja California Sur (BCS) to assess its relationship with age, parity, tobacco smoke exposure, and diet based on survey methodologies. Generalized linear models (GLM) were used to explain the possible association of the different variables with [THg] in hair. Median [THg] in hair was 1.52 µgg-1, ranging from 0.12 to 24.19 µgg-1 and varied significantly by segment. Approximately 72% (54/75) of those evaluated exceed 1 µgg-1 [THg] and 8% (6/75) exceed 5 µgg-1 [THg] in hair. Although frequency of fish consumption contributed significantly to explaining hair [THg], fish consumption only explained 43% of [THg] in a GLM incorporating tobacco exposure and body mass index. This study establishes possible relationships among multiple potential sources of exposure and other factors related to [THg] in hair of women in the prenatal period. A more detailed examination of other sources of exposure and factors contributing to [THg] is warranted.
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Relationship between self-reported fish and shellfish consumption, carbon and nitrogen stable isotope values and total mercury concentrations in pregnant women (II) from Baja California Sur, Mexico. Toxicol Rep 2014; 1:1115-1122. [PMID: 28936396 PMCID: PMC5598523 DOI: 10.1016/j.toxrep.2014.09.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
[THg], δ13C, and δ15N were measured in hair segments of pregnant women from Mexico. Higher δ15N was related to [THg] and frequency of fish and shellfish consumption. THg exposure and assimilation are more complex in higher fish consumption categories. At high fish consumption, trophic level remains elevated while [THg] is lower.
Seafood is a valuable source of nutrients important for fetal development. However, seafood consumption is the main route of exposure to monomethyl mercury (MeHg+) for humans. MeHg+ is highly bioavailable and potentially adversely affects fetal neurodevelopment. MeHg+ exposure from fish consumption varies significantly by age and trophic level of fish consumed as well as the frequency and amount of fish consumed. This study investigates total Hg concentrations ([THg]) in hair segments of pregnant Mexican women in relation to (1) self-reported frequency of fish and shellfish consumption, (2) maternal trophic level and marine diet contributions, determined using hair carbon (C) and nitrogen (N) stable isotopes, and (3) relates [THg] to various hair advisory thresholds. We also examined whether variation in C and N isotope values is explained by self-reported frequency of fish and shellfish consumption. A significant proportion of hair samples had [THg] higher than suggested agency thresholds and, for women within the range of the various advisory thresholds (1–20 μg g−1), the specific statistic used and threshold applied are important considerations for assessing and communicating risk. Individuals enriched in 15N (δ15N values) had higher [THg] as did individuals that reported consuming fish and shellfish more frequently, suggesting that variation in [THg] can be explained by both consumer reported diet and diet as determined by C and N stable isotope assessment. However, at higher reported fish consumption levels the trophic level is maintained while [THg] is paradoxically lower. This suggests that THg exposure and assimilation are more complicated in higher fish frequency consumption categories. [THg] is more variable at the higher concentrations, possibly indicating some exposure to non-dietary Hg, heritable variations affecting Hg toxicodynamics, and BMI and tobacco exposure factors as outlined in our companion paper.
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Correa L, Rea LD, Bentzen R, O'Hara TM. Assessment of mercury and selenium tissular concentrations and total mercury body burden in 6 Steller sea lion pups from the Aleutian Islands. MARINE POLLUTION BULLETIN 2014; 82:175-182. [PMID: 24661459 PMCID: PMC4123997 DOI: 10.1016/j.marpolbul.2014.02.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 02/07/2014] [Accepted: 02/18/2014] [Indexed: 06/03/2023]
Abstract
Concentrations of total mercury ([THg]) and selenium ([TSe]) were measured in several tissue compartments in Steller sea lion (Eumetopias jubatus) pups; in addition we determined specific compartment and body burdens of THg. Compartmental and body burdens were calculated by multiplying specific compartment fresh weight by the [THg] (summing compartment burdens equals body burden). In all 6 pup tissue sets (1) highest [THg] was in hair, (2) lowest [THg] was in bone, and (3) pelt, muscle and liver burdens contributed the top three highest percentages of THg body burden. In 5 of 6 pups the Se:Hg molar ratios among compartments ranged from 0.9 to 43.0. The pup with the highest hair [THg] had Se:Hg molar ratios in 9 of 14 compartments that were ⩽ 0.7 potentially indicating an inadequate [TSe] relative to [THg].
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Affiliation(s)
- Lucero Correa
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, PO Box 755940, Fairbanks, AK 99775-5940, USA.
| | - Lorrie D Rea
- Division of Wildlife Conservation, Alaska Department of Fish and Game and Institute of Northern Engineering, Water and Environmental Research Center, University of Alaska Fairbanks, PO Box 755910, Fairbanks, AK 99775-5910, USA
| | - Rebecca Bentzen
- Institute of Arctic Biology and Department of Veterinary Medicine, University of Alaska Fairbanks, PO Box 757000, Fairbanks, AK 99775-5940, USA
| | - Todd M O'Hara
- Institute of Arctic Biology and Department of Veterinary Medicine, University of Alaska Fairbanks, PO Box 757000, Fairbanks, AK 99775-5940, USA
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USE OF CELLULOSE FILTER PAPER TO QUANTIFY WHOLE-BLOOD MERCURY IN TWO MARINE MAMMALS: VALIDATION STUDY. J Wildl Dis 2014; 50:271-8. [DOI: 10.7589/2013-08-214] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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McKinney MA, Iverson SJ, Fisk AT, Sonne C, Rigét FF, Letcher RJ, Arts MT, Born EW, Rosing-Asvid A, Dietz R. Global change effects on the long-term feeding ecology and contaminant exposures of East Greenland polar bears. GLOBAL CHANGE BIOLOGY 2013; 19:2360-72. [PMID: 23640921 DOI: 10.1111/gcb.12241] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 03/31/2013] [Indexed: 05/04/2023]
Abstract
Rapid climate changes are occurring in the Arctic, with substantial repercussions for arctic ecosystems. It is challenging to assess ecosystem changes in remote polar environments, but one successful approach has entailed monitoring the diets of upper trophic level consumers. Quantitative fatty acid signature analysis (QFASA) and fatty acid carbon isotope (δ(13) C-FA) patterns were used to assess diets of East Greenland (EG) polar bears (Ursus maritimus) (n = 310) over the past three decades. QFASA-generated diet estimates indicated that, on average, EG bears mainly consumed arctic ringed seals (47.5 ± 2.1%), migratory subarctic harp (30.6 ± 1.5%) and hooded (16.7 ± 1.3%) seals and rarely, if ever, consumed bearded seals, narwhals or walruses. Ringed seal consumption declined by 14%/decade over 28 years (90.1 ± 2.5% in 1984 to 33.9 ± 11.1% in 2011). Hooded seal consumption increased by 9.5%/decade (0.0 ± 0.0% in 1984 to 25.9 ± 9.1% in 2011). This increase may include harp seal, since hooded and harp seal FA signatures were not as well differentiated relative to other prey species. Declining δ(13) C-FA ratios supported shifts from more nearshore/benthic/ice-associated prey to more offshore/pelagic/open-water-associated prey, consistent with diet estimates. Increased hooded seal and decreased ringed seal consumption occurred during years when the North Atlantic Oscillation (NAO) was lower. Thus, periods with warmer temperatures and less sea ice were associated with more subarctic and less arctic seal species consumption. These changes in the relative abundance, accessibility, or distribution of arctic and subarctic marine mammals may have health consequences for EG polar bears. For example, the diet change resulted in consistently slower temporal declines in adipose levels of legacy persistent organic pollutants, as the subarctic seals have higher contaminant burdens than arctic seals. Overall, considerable changes are occurring in the EG marine ecosystem, with consequences for contaminant dynamics.
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