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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] [MESH Headings] [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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Keenan M, Misarti N, Horstmann L, Crawford SG, O'Hara T, Rea LD, Avery JP. Total mercury concentrations in Steller sea lion bone: Variability among locations and elements. MARINE POLLUTION BULLETIN 2024; 203:116471. [PMID: 38754323 DOI: 10.1016/j.marpolbul.2024.116471] [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: 03/28/2024] [Revised: 05/03/2024] [Accepted: 05/04/2024] [Indexed: 05/18/2024]
Abstract
Mercury is a global contaminant that bioaccumulates in a tissue-specific manner in long-lived predators such as Steller sea lions (SSL). Bone is a well-preserved material amenable for studying millennial scale trends; however, little is known about the distribution and variability of total mercury concentrations ([THg]) within individual bones and among bone elements in SSL. We assessed SSL bone [THg] variability with respect to physiologic age, bone type, longitudinally within a bone, and among bone elements. Pup bones (mean ± SD; 31.4 ± 13.58 ppb) had greater [THg] than adults (7.9 ± 1.91 ppb). There were greater and more variable [THg] within individual long bones near epiphyses compared to mid-diaphysis. Pup spongy bone in ribs (62.7 ± 44.79 ppb) had greater [THg] than long bones (23.5 ± 8.83 ppb) and phalanges (19.6 ± 10.78 ppb). These differences are likely due to variability in bone composition, growth, and turnover rate. This study informs standardized sampling procedures for [THg] in bone to improve interpretations of mercury variability over time and space.
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Affiliation(s)
- Mary Keenan
- Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska, 1764 Tanana Loop, PO Box 75 5910, Fairbanks, AK 99775, USA; College of Fisheries and Ocean Sciences, University of Alaska, 2150 Koyukuk Drive, PO Box 757220, Fairbanks, AK 99775, USA.
| | - Nicole Misarti
- Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska, 1764 Tanana Loop, PO Box 75 5910, Fairbanks, AK 99775, USA
| | - Lara Horstmann
- College of Fisheries and Ocean Sciences, University of Alaska, 2150 Koyukuk Drive, PO Box 757220, Fairbanks, AK 99775, USA
| | - Stephanie G Crawford
- Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska, 1764 Tanana Loop, PO Box 75 5910, Fairbanks, AK 99775, USA
| | - Todd O'Hara
- Veterinary Integrative Biosciences, School of Veterinary Medicine & Biomedical Sciences, Texas A&M University, 402 Raymond Stotzer Pkwy, College Station, TX 77843, USA
| | - Lorrie D Rea
- Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska, 1764 Tanana Loop, PO Box 75 5910, Fairbanks, AK 99775, USA
| | - Julie P Avery
- Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska, 1764 Tanana Loop, PO Box 75 5910, Fairbanks, AK 99775, USA
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Trifari MP, Wooller MJ, Rea L, O'Hara TM, Lescord GL, Parnell AC, Barst BD. Compound-specific stable isotopes of amino acids reveal influences of trophic level and primary production sources on mercury concentrations in fishes from the Aleutian Islands, Alaska. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 908:168242. [PMID: 37918743 DOI: 10.1016/j.scitotenv.2023.168242] [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: 06/14/2023] [Revised: 10/12/2023] [Accepted: 10/29/2023] [Indexed: 11/04/2023]
Abstract
Total mercury concentrations ([THg]) exceed thresholds of concern in some Steller sea lion (Eumetopias jubatus) tissues from certain portions of the Aleutian Islands, Alaska. We applied compound-specific stable isotope analyses of both carbon and nitrogen in amino acids from fish muscle tissue to quantify the proportional contributions of primary production sources and trophic positions of eight prey species (n = 474 total) that are part of Steller sea lion diets. Previous THg analyses of fish muscle, coupled with monomethylmercury analyses of a subset of samples, substantiated previous findings that fishes from the west of Amchitka Pass, a discrete oceanographic boundary of the Aleutian Archipelago, have higher muscle Hg concentrations relative to fishes from the east. The δ13C values of essential amino acids (EAAs) in fish muscle demonstrated that although most fishes obtained their EAAs primarily from algae, some species varied in the extent to which they relied on this EAA source. The δ15N values of phenylalanine (0.9 to 7.8 ‰), an indicator of the isotopic baseline of a food web, varied widely within and among fish species. Trophic position estimates, accounting for this baseline variation, were higher from the west relative to the east of the pass for some fish species. Trophic magnification slopes using baseline-corrected trophic position estimates indicated similar rates of Hg biomagnification to the east and west of Amchitka Pass. Multiple linear regression models revealed that trophic position was the most important driver of fish muscle [THg] with less variation explained by other parameters. Thus, higher trophic positions but not the rate of Hg biomagnification to the west of Amchitka Pass may play a role in the regional differences in both fish and Steller sea lion [THg]. Although, differences in Hg contamination and uptake at the base of the east and west food webs could not be excluded.
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Affiliation(s)
- Michelle P Trifari
- Department of Marine Biology, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, USA; Alaska Stable Isotope Facility, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK, USA; Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Matthew J Wooller
- Department of Marine Biology, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, USA; Alaska Stable Isotope Facility, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK, USA; Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Lorrie Rea
- Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Todd M O'Hara
- Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK, USA; Bilingual Laboratory of Toxicology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Gretchen L Lescord
- University of Florida, School of Forest Fisheries, and Geomatics Sciences, USA; Cooperative Freshwater Ecology Unit, Laurentian University, Ontario, Canada; Wildlife Conservation Society Canada, Thunder Bay, Ontario, Canada
| | - Andrew C Parnell
- Hamilton Institute, Insight Centre for Data Analytics, Maynooth University, Maynooth, Ireland
| | - Benjamin D Barst
- Alaska Stable Isotope Facility, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK, USA; Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK, USA.
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Crawford SG, Coker RH, O’Hara TM, Breed GA, Gelatt T, Fadely B, Burkanov V, Rivera PM, Rea LD. Fasting durations of Steller sea lion pups vary among subpopulations-evidence from two plasma metabolites. CONSERVATION PHYSIOLOGY 2023; 11:coad084. [PMID: 38026798 PMCID: PMC10673819 DOI: 10.1093/conphys/coad084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 08/28/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023]
Abstract
Geographic differences in population growth trends are well-documented in Steller sea lions (Eumetopias jubatus), a species of North Pacific pinniped listed under the U.S. Endangered Species Act in 1990 following a marked decline in population abundance that began during the 1970s. As population growth is intrinsically linked to pup production and survival, examining factors related to pup physiological condition provides useful information to management authorities regarding potential drivers of regional differences. During dam foraging trips, pups predictably transition among three fasting phases, distinguished by the changes in the predominant metabolic byproduct. We used standardized ranges of two plasma metabolites (blood urea nitrogen and β-hydroxybutyrate) to assign pups to fasting categories (n = 1528, 1990-2016, 12 subpopulations): Recently Fed-Phase I (digestion/assimilation-expected hepatic/muscle glycogen usage), Phase II (expected lipid utilization), transitioning between Phases II-III (expected lipid utilization with increased protein reliance), or Phase III (expected protein catabolism). As anticipated, the majority of pups were classified as Recently Fed-Phase I (overall mean proportion = 0.72) and few pups as Phase III (overall mean proportion = 0.04). By further comparing pups in Short (Recently Fed-Phase II) and Long (all other pups) duration fasts, we identified three subpopulations with significantly (P < 0.03) greater proportions of pups dependent upon endogenous sources of energy for extended periods, during a life stage of somatic growth and development: the 1) central (0.27 ± 0.09) and 2) western (0.36 ± 0.13) Aleutian Island (declining population trend) and 3) southern Southeast Alaska (0.32 ± 0.06; increasing population trend) subpopulations had greater Long fast proportions than the eastern Aleutian Islands (0.10 ± 0.05; stabilized population). Due to contrasting population growth trends among these highlighted subpopulations over the past 50+ years, both density-independent and density-dependent factors likely influence the dam foraging trip duration, contributing to longer fasting durations for pups at some rookeries.
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Affiliation(s)
- Stephanie G Crawford
- Department of Biology and Wildlife and Institute of Northern Engineering, University of Alaska Fairbanks, 1764 Tanana Loop, Fairbanks, Alaska 99775, USA
| | - Robert H Coker
- Montana Center for Work Physiology and Exercise Metabolism, University of Montana, 32 Campus Drive, Missoula, Montana 59812, USA
| | - Todd M O’Hara
- Veterinary Integrative Biosciences, School of Veterinary Medicine & Biomedical Sciences, Texas A&M University, 402 Raymond Stotzer Parkway, Bldg 2, College Station, Texas 77843, USA
| | - Greg A Breed
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA
| | - Tom Gelatt
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way N.E., Bldg. 4, Seattle, Washington 98115, USA
| | - Brian Fadely
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way N.E., Bldg. 4, Seattle, Washington 98115, USA
| | - Vladimir Burkanov
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way N.E., Bldg. 4, Seattle, Washington 98115, USA
| | - Patricia M Rivera
- Center for Alaska Native Health Research, Institute of Arctic Biology, University of Alaska Fairbanks, 2141 Koyukuk Drive, Fairbanks, Alaska 99775, USA
| | - Lorrie D Rea
- Institute of Northern Engineering, University of Alaska Fairbanks, 1764 Tanana Loop, Fairbanks, Alaska 99775, USA
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Cyr AP, Drew KA, Corsetti S, Seitz AC, Sutton TM, López JA, Wooller MJ, O'Hara T. Ecotoxicology of mercury concentrations in arctic lamprey (Lethenteron camtschaticum). ENVIRONMENTAL RESEARCH 2023; 237:116955. [PMID: 37643685 PMCID: PMC10838160 DOI: 10.1016/j.envres.2023.116955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 08/10/2023] [Accepted: 08/21/2023] [Indexed: 08/31/2023]
Abstract
Arctic lamprey (Lethenteron camtschaticum) is an important dietary resource for rural and indigenous communities in parts of Alaska, with some commercial use. As with many fish species harvested for human consumption, there are concerns regarding mercury concentrations ([Hg]) in Arctic lamprey that may impact human health. To date, information regarding the life cycle and diet of Arctic lamprey is scarce, with no published studies examining [Hg] in Arctic lamprey tissues. Our goals were to investigate the feeding ecology of Arctic lamprey from the Bering Sea, determine how diet and potential dietary shifts might influence [Hg] in muscle, and determine if current [Hg] may pose a human health risk. The mean total [Hg] in Arctic lamprey muscle (n = 98) was 19 ng/g wet-weight. Log transformed total [Hg] were not associated with any measured biological variables including length, mass, δ13C values, or δ15N values. A stable isotope mixing model estimated that capelin (Mallotus villosus) accounted for 40.0 ± 4.0% of the Arctic lamprey diet, while Pacific sand lance (Ammodytes hexapterus) and Pacific herring (Clupea pallasii) accounted for 37.8 ± 3.1% and 22.2 ± 3.5% respectively. Finally, diet percentage compositions shifted based on size class (i.e., medium versus large). These results indicated that feeding location, bioaccumulation, and biomagnification are not important drivers of [Hg] in Arctic lamprey and current [Hg] do not pose a human health risk. Taken together, this research further expands our knowledge of Arctic lamprey trophic ecology in the eastern Bering Sea.
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Affiliation(s)
- Andrew P Cyr
- Department of Veterinary Medicine, University of Alaska Fairbanks, 901 Koyukuk Drive, Fairbanks, AK 99775-7750, USA.
| | - Katie A Drew
- College of Fisheries and Ocean Sciences, 2150 Koyukuk Drive, Fairbanks, AK 99775-7220, USA
| | - Sierra Corsetti
- Department of Biology and Wildlife, PO Box 756100, Fairbanks, AK 99775-6100, USA
| | - Andrew C Seitz
- College of Fisheries and Ocean Sciences, 2150 Koyukuk Drive, Fairbanks, AK 99775-7220, USA
| | - Trent M Sutton
- College of Fisheries and Ocean Sciences, 2150 Koyukuk Drive, Fairbanks, AK 99775-7220, USA
| | - J Andrés López
- College of Fisheries and Ocean Sciences, 2150 Koyukuk Drive, Fairbanks, AK 99775-7220, USA; University of Alaska Museum of the North, University of Alaska, Fairbanks, 907 Yukon Drive, Fairbanks, AK 99775-6960, USA
| | - Matthew J Wooller
- College of Fisheries and Ocean Sciences, 2150 Koyukuk Drive, Fairbanks, AK 99775-7220, USA; Water and Environmental Research Center, Institute of Northern Engineering, 306 Tanana Loop, Fairbanks, AK 99775-5910, USA; Alaska Stable Isotope Facility, University of Alaska, Fairbanks, 907 Yukon Drive, Fairbanks, AK 99775-5910, USA
| | - Todd O'Hara
- Water and Environmental Research Center, Institute of Northern Engineering, 306 Tanana Loop, Fairbanks, AK 99775-5910, USA; Bilingual Laboratory of Toxicology, Veterinary Integrative Biosciences, School of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA
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Cyr A, Murillo-Cisneros DA, López JA, Furin C, O'Hara T. Comparison of Two Total Mercury Screening and Assessment Methods in Fishes: Biopsy Punch and Dried Muscle Samples. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2023; 85:119-128. [PMID: 37573269 DOI: 10.1007/s00244-023-01020-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 07/25/2023] [Indexed: 08/14/2023]
Abstract
Rapid and effective quantification of total mercury concentrations ([THg]) in fish muscle is an important part of ongoing monitoring to provide reliable and near real-time public health guidance. Methods for quantifying THg in fish muscle frequently require the use of large sample mass and numerous preparation steps. Wet (aka fresh weight) biopsy punch samples of fish muscle have been used to quantify THg directly, without drying and homogenization. Both methods have advantages and disadvantages. We compare the use of fresh weight biopsy punches for quantifying THg to using larger, dried homogenized samples. The [THg] determination for the two sampling methods was EPA method 7473. Three separate biopsy punch samples and a large muscle sample were taken from each fish and analyzed on a Direct Mercury Analyzer. There were no statistical differences between mean log transformed wet weight [THg] from biopsy punches and homogenized muscle across all samples or within individual species. Similarly, across the range of [THg] (7.5-612.7 ng/g ww), linear regression of [THg] from biopsy punch and homogenized muscle samples was not different from a 1:1 linear relationship. Linear regression statistics of [THg] with fish fork length produced similar results for both biopsy punch and homogenized muscle samples. However, the coefficient of variation among biopsy punch replicates for individual fish was frequently above the acceptable threshold of 15%. We recommend biopsy punches be used as an effective tool for broad-scale rapid monitoring of fish resources for Hg, while homogenized muscle samples be used for fine-scale ecological and health questions.
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Affiliation(s)
- Andrew Cyr
- Department of Veterinary Medicine, University of Alaska Fairbanks, 2141 Koyukuk Dr, Fairbanks, AK, 99775-7750, USA.
| | - Daniella A Murillo-Cisneros
- Centro de Investigaciones Biológicas Del Noroeste, S.C. Planeación Ambiental Y Conservación, Instituto Politécnico Nacional 195, Playa Palo de Santa Rita Sur, 23096, La Paz, Baja California Sur, Mexico
| | - J Andrés López
- University of Alaska Museum of the North, University of Alaska, 907 Yukon Drive, Fairbanks, AK, 99775-6960, USA
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 905 N Koyukuk Drive, Fairbanks, AK, 99775-7220, USA
| | - Christoff Furin
- Alaska Department of Environmental Conservation, 5251 Dr. Martin Luther King Jr. Ave., Anchorage, AK, 99507, USA
| | - Todd O'Hara
- Bilingual Laboratory of Toxicology, Veterinary Integrative Biosciences, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA
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Jonsson S, Mastromonaco MN, Wang F, Bravo AG, Cairns WRL, Chételat J, Douglas TA, Lescord G, Ukonmaanaho L, Heimbürger-Boavida LE. Arctic methylmercury cycling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 850:157445. [PMID: 35882324 DOI: 10.1016/j.scitotenv.2022.157445] [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: 01/31/2022] [Revised: 07/12/2022] [Accepted: 07/13/2022] [Indexed: 06/15/2023]
Abstract
Anthropogenic mercury (Hg) undergoes long-range transport to the Arctic where some of it is transformed into methylmercury (MeHg), potentially leading to high exposure in some Arctic inhabitants and wildlife. The environmental exposure of Hg is determined not just by the amount of Hg entering the Arctic, but also by biogeochemical and ecological processes occurring in the Arctic. These processes affect MeHg uptake in biota by regulating the bioavailability, methylation and demethylation, bioaccumulation and biomagnification of MeHg in Arctic ecosystems. Here, we present a new budget for pools and fluxes of MeHg in the Arctic and review the scientific advances made in the last decade on processes leading to environmental exposure to Hg. Methylation and demethylation are key processes controlling the pool of MeHg available for bioaccumulation. Methylation of Hg occurs in diverse Arctic environments including permafrost, sediments and the ocean water column, and is primarily a process carried out by microorganisms. While microorganisms carrying the hgcAB gene pair (responsible for Hg methylation) have been identified in Arctic soils and thawing permafrost, the formation pathway of MeHg in oxic marine waters remains less clear. Hotspots for methylation of Hg in terrestrial environments include thermokarst wetlands, ponds and lakes. The shallow sub-surface enrichment of MeHg in the Arctic Ocean, in comparison to other marine systems, is a possible explanation for high MeHg concentrations in some Arctic biota. Bioconcentration of aqueous MeHg in bacteria and algae is a critical step in the transfer of Hg to top predators, which may be dampened or enhanced by the presence of organic matter. Variable trophic position has an important influence on MeHg concentrations among populations of top predator species such as ringed seal and polar bears distributed across the circumpolar Arctic. These scientific advances highlight key processes that affect the fate of anthropogenic Hg deposited to Arctic environments.
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Affiliation(s)
- Sofi Jonsson
- Department of Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden.
| | | | - Feiyue Wang
- Centre for Earth Observation Science, and Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Andrea G Bravo
- Department of Marine Biology and Oceanography, Institut de Ciències del Mar (ICM-CSIC), Barcelona, Spain
| | - Warren R L Cairns
- CNR Institute of Polar Sciences and Ca' Foscari University, Venice, Italy
| | - John Chételat
- Environment and Climate Change Canada, National Wildlife Research Centre, Ottawa, ON, Canada
| | - Thomas A Douglas
- U.S. Army Cold Regions Research and Engineering Laboratory, Fort Wainwright, AK, USA
| | - Gretchen Lescord
- Wildlife Conservation Society Canada and Laurentian University, Vale Living with Lakes Center, Sudbury, Ontario, Canada
| | - Liisa Ukonmaanaho
- Natural Resources Institute Finland (Luke), P.O. Box 2, FI-00791 Helsinki, Finland
| | - Lars-Eric Heimbürger-Boavida
- CNRS/INSU,Aix Marseille Université,Université de Toulon, IRD, Mediterranean Institute of Oceanography (MIO), Marseille, France
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8
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Walther EJ, Arthur DE, Cyr A, Fraley KM, Cubbage T, Hinkle E, McMahon J, Westley PAH. Ecotoxicology of mercury in burbot (Lota lota) from interior Alaska and insights towards human health. CHEMOSPHERE 2022; 298:134279. [PMID: 35283142 PMCID: PMC9081214 DOI: 10.1016/j.chemosphere.2022.134279] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 03/03/2022] [Accepted: 03/07/2022] [Indexed: 05/26/2023]
Abstract
Fish consumption has many health benefits, but exposure to contaminants, such as mercury (Hg), in fish tissue can be detrimental to human health. The Tanana River drainage, Alaska, USA supports the largest recreational harvest of burbot (Lota lota) in the state, yet information to evaluate the potential risks of consumption by humans is lacking. To narrow this knowledge gap, we sought to (i) quantify the concentrations of total Hg ([THg]) in burbot muscle and liver tissue and the ratio between the two tissues, (ii) assess the effect of age, length, and sex on [THg] in muscle and liver tissue, (iii) evaluate if [THg] in muscle tissue varied based on trophic information, and (iv) compare observed [THg] to consumption guidelines and statewide baseline data. The mean [THg] was 268.2 ng/g ww for muscle tissue and 62.3 ng/g ww for liver tissue. Both muscle [THg] and liver [THg] values were positively associated with fish length. Trophic information (δ15N and δ13C) was not significantly related to measured [THg] in burbot muscle, which is inconsistent with typical patterns of biomagnification observed in other fishes. All burbot sampled were within the established categories for consumption recommendations determined by the State of Alaska for women of childbearing age and children. Our results provide the necessary first step towards informed risk assessment of burbot consumption in the Tanana drainage and offer parallels to fisheries and consumers throughout the subarctic and Arctic region.
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Affiliation(s)
- Eric J Walther
- Department of Fisheries, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA.
| | - Donald E Arthur
- Department of Fisheries, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA.
| | - Andrew Cyr
- Department of Fisheries, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA; Department of Veterinary Medicine, College of Natural Sciences and Mathematics, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA
| | - Kevin M Fraley
- Arctic Beringia Program, Wildlife Conservation Society, Fairbanks, AK, 99709, USA
| | - Taylor Cubbage
- Department of Fisheries, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA
| | - Elizabeth Hinkle
- Department of Fisheries, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA
| | - Julia McMahon
- Department of Fisheries, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA
| | - Peter A H Westley
- Department of Fisheries, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA.
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Xie J, Tao L, Wu Q, Li T, Yang C, Lin T, Liu B, Li G, Chen D. Mercury and selenium in squids from the Pacific Ocean and Indian Ocean: The distribution and human health implications. MARINE POLLUTION BULLETIN 2021; 173:112926. [PMID: 34536705 DOI: 10.1016/j.marpolbul.2021.112926] [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: 08/01/2021] [Revised: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
Squids are globally distributed. Hg-contaminated squids may have high risks on humans. With abundant Se (antagonistic effect on Hg), the risks can be reduced. We collected squids around the world (Northwest Pacific Ocean, Southeast Pacific Ocean and Indian Ocean). Concentrations of Hg and Se were region-based and tissue-based. The higher content of Se were, the lower relative Hg levels were. The correlation between Se:Hg and Se was the strongest in the digestive gland. The values of Se:Hg and THQ all confirm that the health risk was lower in samples with higher concentrations of Se. Despite the risk assessment by Se:Hg, BRV and THQ analysis showed no risk when consumed in moderation, the maximum daily intake is provided based on Monte Carlo simulation. In future, when evaluating the risks cause by Hg exposure and providing the recommended daily amount, it may need to concurrent consideration of Se levels.
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Affiliation(s)
- Jingqian Xie
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China; Skate Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environment and Resources, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Ling Tao
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Qiang Wu
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Tiejun Li
- Zhejiang Marine Fisheries Research Institute, Key Laboratory of Sustainable Utilization of Technology Research for Fishery Resource of Zhejiang Province, Zhoushan, 316021, China
| | - Chenghu Yang
- Zhejiang Marine Fisheries Research Institute, Key Laboratory of Sustainable Utilization of Technology Research for Fishery Resource of Zhejiang Province, Zhoushan, 316021, China
| | - Tian Lin
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Bilin Liu
- College of Marine Science, Shanghai Ocean University, Shanghai 201306, China; The Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources, Ministry of Education, Shanghai 201306, China
| | - Gang Li
- College of Marine Science, Shanghai Ocean University, Shanghai 201306, China; The Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources, Ministry of Education, Shanghai 201306, China.
| | - Duofu Chen
- College of Marine Science, Shanghai Ocean University, Shanghai 201306, China
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10
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Gabara SS, Konar BH, Edwards MS. Biodiversity loss leads to reductions in community‐wide trophic complexity. Ecosphere 2021. [DOI: 10.1002/ecs2.3361] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Scott S. Gabara
- Department of Biology & Coastal Marine Institute Laboratory San Diego State University San Diego California92182USA
- Department of Environmental Science and Policy University of California Davis California95616USA
| | - Brenda H. Konar
- College of Fisheries and Ocean Sciences University of Alaska Fairbanks Fairbanks Alaska99775USA
| | - Matthew S. Edwards
- Department of Biology & Coastal Marine Institute Laboratory San Diego State University San Diego California92182USA
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11
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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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12
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Lian M, Castellini JM, Kuhn T, Rea L, Bishop L, Keogh M, Kennedy SN, Fadely B, van Wijngaarden E, Maniscalco JM, O'Hara T. Assessing oxidative stress in Steller sea lions (Eumetopias jubatus): Associations with mercury and selenium concentrations. Comp Biochem Physiol C Toxicol Pharmacol 2020; 235:108786. [PMID: 32413494 DOI: 10.1016/j.cbpc.2020.108786] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/27/2020] [Accepted: 04/28/2020] [Indexed: 02/07/2023]
Abstract
Selenium (Se) bioavailability is required for synthesis and function of essential Se-dependent antioxidants, including the enzyme glutathione peroxidase (GPx). Strong interactions between monomethyl mercury and Se impair the critical antioxidant role of Se. Approximately 20% of Steller sea lion (Eumetopias jubatus, SSL) pups sampled in the western Aleutian Islands, Alaska, had total Hg concentrations ([THg]) measured in hair and whole blood above thresholds of concern for adverse physiologic effects in pinnipeds. Importantly, low molar ratios of TSe:THg, in some cases < 1 in several tissues (hair, liver, pelt, muscle, spleen, intestine, heart, lungs, brain) were documented for one SSL pup with [THg] above threshold of concern, which may lead to antioxidant deficiency. Our aim with this study was to evaluate the relationship between circulating [THg], [MeHg+], [TSe] and TSe:THg molar ratio status relative to oxidative stress and antioxidants measured during general anesthesia in free-ranging SSL. We captured, anesthetized and sampled newborn SSL pups at rookeries located in the Aleutian Islands or Gulf of Alaska. Biomarkers analyzed for oxidative stress included 4-hydroxynenonal and thiobarbituric acid reactive substances (4-HNE and TBARS, respectively, lipid peroxidation), protein carbonyl content (PCC, protein oxidation), and GPx activity as a key indicator for Se-dependent antioxidant defense levels. We found a negative association between TBARS and [TSe], and SSL with low [TSe] had higher concentrations of 4-HNE than those with intermediate [TSe]. These results suggest that SSL with lower [TSe] experience increased lipid peroxidation potentially associated with [THg] status.
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Affiliation(s)
- Marianne Lian
- Department of Veterinary Medicine, University of Alaska Fairbanks, 2141 Koyokuk Dr, Fairbanks, AK 99775-7750, USA; Department of Chemistry and Biochemistry, University of Alaska Fairbanks, 900 Yukon Dr Rm. 194, Fairbanks, AK 99775-6160, USA.
| | - J Margaret Castellini
- Department of Veterinary Medicine, University of Alaska Fairbanks, 2141 Koyokuk Dr, Fairbanks, AK 99775-7750, USA.
| | - Thomas Kuhn
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, 900 Yukon Dr Rm. 194, Fairbanks, AK 99775-6160, USA.
| | - Lorrie Rea
- Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, 1764 Tanana Loop, Fairbanks, AK 99775, USA.
| | - Louise Bishop
- Department of Biology and Wildlife, University of Alaska Fairbanks, 2090 Koyokuk Dr, Fairbanks, AK 99775, USA.
| | - Mandy Keogh
- Division of Wildlife Conservation, Alaska Department of Fish and Game, P.O. Box 110024, Douglas, AK 99811-0024, USA.
| | - Stephanie N Kennedy
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, 900 Yukon Dr Rm. 194, Fairbanks, AK 99775-6160, USA; Harvard Medical School and Division of Gastroenterology, Boston Children's Hospital, 300 Longwood Ave. Enders 6th Floor, RM 650, Boston, MA 02115, USA.
| | - Brian Fadely
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, WA 98115, USA.
| | - Edwin van Wijngaarden
- University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA.
| | - John M Maniscalco
- Alaska SeaLife Center, 301 Railway Avenue, P.O. Box 1329, Seward, AK 99664, USA.
| | - Todd O'Hara
- Department of Veterinary Medicine, University of Alaska Fairbanks, 2141 Koyokuk Dr, Fairbanks, AK 99775-7750, USA; Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA.
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13
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Optimization of a Digestion Method to Determine Total Mercury in Fish Tissue by Cold Vapor Atomic Fluorescence Spectrophotometry. Methods Protoc 2020; 3:mps3020045. [PMID: 32585795 PMCID: PMC7359707 DOI: 10.3390/mps3020045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 02/03/2023] Open
Abstract
Several microwave-assisted digestion methods were tested at the Centro de Estudios Aplicados en Química laboratory in Quito, Ecuador, to determine the accuracy and performance efficiency of the mineralization process for the determination of total mercury in fish tissue by cold vapor atomic fluorescence spectrophotometry. The use of MARSEasyPrep high-pressure vessels, low amounts of reagents (1 cm3 HNO3, 1 cm3 H2O2, and 1 cm3 HClO4), an irradiation temperature of 210 °C, and 35 min of mineralization time resulted in accurate performance, with recoveries of certified reference material DORM-4 between 90.1% and 105.8%. This is better than the Association of Official Analytical Chemists 2015.01 method, which has a reported accuracy of 81%. The repeatability precision and intermediate precision were established at three concentration levels (0.167, 0.500, and 0.833 mg·kg−1) and expressed as the percentage of the relative standard deviation ranging from 1.5% to 3.0% and 1.7% to 4.2%, respectively. Further, the method was satisfactorily applied to analyze fortified samples of tilapia (Oreochromis niloticus), with recoveries ranging from 98.3% to 104.3%. The instrumental limits of detection and quantification were 0.118 µg·dm−3 and 0.394 µg·dm−3, respectively.
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Lischka A, Lacoue-Labarthe T, Bustamante P, Piatkowski U, Hoving HJT. Trace element analysis reveals bioaccumulation in the squid Gonatus fabricii from polar regions of the Atlantic Ocean. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 256:113389. [PMID: 31685327 DOI: 10.1016/j.envpol.2019.113389] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 09/20/2019] [Accepted: 10/11/2019] [Indexed: 06/10/2023]
Abstract
The boreoatlantic gonate squid (Gonatus fabricii) represents important prey for top predators-such as marine mammals, seabirds and fish-and is also an efficient predator of crustaceans and fish. Gonatus fabricii is the most abundant cephalopod in the northern Atlantic and Arctic Ocean but the trace element accumulation of this ecologically important species is unknown. In this study, trace element concentrations (Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, and Zn) were analysed from the mantle muscle and the digestive gland tissue of juveniles, adult females, and adult males that were captured south of Disko Island off West-Greenland. To assess the feeding habitat and trophic position of this species, stable isotopes of carbon (δ13C) and nitrogen (δ15N) were measured in their muscle tissue. Mercury concentrations were positively correlated with size (mantle length) and trophic position. The Hg/Se ratio was assessed because Se has been suggested to play a protective role against Hg toxicity and showed a molar surplus of Se relative to Hg. Cadmium concentrations in the digestive gland were negatively correlated with size and trophic position (δ15N), which suggested a dietary shift from Cd-rich crustaceans towards Cd-poor fish during ontogeny. This study provides trace element concentration data for G. fabricii from Greenlandic waters, which represents baseline data for a northern cephalopod species. Within West-Greenland waters, G. fabricii appears to be an important vector for the transfer of Cd in the Arctic pelagic food web.
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Affiliation(s)
- A Lischka
- AUT School of Science New Zealand, Auckland University of Technology, Private Bag 92006, 1142, Auckland, New Zealand.
| | - T Lacoue-Labarthe
- Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, 2 rue Olympe de Gouges, 17000, La Rochelle, France
| | - P Bustamante
- Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, 2 rue Olympe de Gouges, 17000, La Rochelle, France
| | - U Piatkowski
- GEOMAR, Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105, Kiel, Germany
| | - H J T Hoving
- GEOMAR, Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105, Kiel, Germany
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15
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Cyr AP, López JA, Wooller MJ, Whiting A, Gerlach R, O'Hara T. Ecological drivers of mercury concentrations in fish species in subsistence harvests from Kotzebue Sound, Alaska. ENVIRONMENTAL RESEARCH 2019; 177:108622. [PMID: 31419713 DOI: 10.1016/j.envres.2019.108622] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 06/10/2023]
Abstract
The State of Alaska assesses human exposure to mercury (Hg) via fish consumption producing consumption guidelines for fish tailored for children and women of childbearing age. Under these guidelines, unrestricted consumption is suggested for many fish species, while limited consumption is recommended for others. Subsequent questions have arisen regarding ecological drivers influencing [Hg] in fishes consumed by Alaskans. This community-assisted public health study evaluates [Hg] in fishes from Kotzebue Sound to examine factors that may drive observed [Hg]. We examined eight species of subsistence harvested fish (least cisco, chum salmon, Pacific herring, humpback whitefish, sheefish, starry flounder, Pacific tomcod, and fourhorn sculpin) from Kotzebue Sound. We report total Hg concentrations ([THg]) and monomethyl Hg+ concentrations ([MeHg+]) in the context of various factors (such as species, fork length, carbon and nitrogen stable isotope (δ15N or δ13C)) values that may influence [Hg] and [MeHg+]. Across all 297 fish, [THg] ranged from 3.4 - 235.2 ng/g ww. [THg] was positively correlated with fork length in six of eight fish species, as well as with trophic level (indicated by δ15N values) in five species. [MeHg+] was positively correlated with fork length in four species, and with δ15N values over all specimens examined, and specifically for three individual species. In six of the seven species analyzed, %MeHg was >80% of [THg]. This value decreased with fork length in three species, with no relationship for δ15N values in any species. Among top ranked models based on Akaike Information Criterion correction (AICc), fork length was more frequently included as an explanatory factor for [Hg] than δ15N or δ13C values. The food web magnification factor for [THg] was 11.3, and 12.6 for [MeHg+]. Biomagnification is likely driving [THg] and [MeHg+] over the entire food web, while within species, bioaccumulation is likely a stronger driver of [THg] and [MeHg+] than feeding ecology or trophic position. The [THg] for all species fell within the established unrestricted consumption guideline of 200 ng/g weight wet as established by the State of Alaska's fish consumption guidelines for Hg.
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Affiliation(s)
- Andrew P Cyr
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 905 N Koyukuk Drive, Fairbanks, AK, 99775-7220, USA.
| | - J Andrés López
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 905 N Koyukuk Drive, Fairbanks, AK, 99775-7220, USA; University of Alaska Museum of the North, University of Alaska, Fairbanks, 907 Yukon Drive, Fairbanks, AK, 99775-6960, USA
| | - Matthew J Wooller
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 905 N Koyukuk Drive, Fairbanks, AK, 99775-7220, USA; Water and Environmental Research Center, Institute of Northern Engineering, 306 Tanana Loop, Fairbanks, AK, 99775-5860, USA; Alaska Stable Isotope Facility, University of Alaska, Fairbanks, 907 Yukon Drive, Fairbanks, AK, 99775-6960, USA
| | - Alex Whiting
- Native Village of Kotzebue, 600 Fifth Ave., Kotzebue, AK, 99752, USA
| | - Robert Gerlach
- Office of the State Veterinarian, Alaska Division of Environmental Health, 5251 Drive. Martin Luther King Jr. Ave., Anchorage, AK, 99507, USA
| | - Todd O'Hara
- Department of Veterinary Medicine, University of Alaska Fairbanks, 901 Koyukuk Drive, Fairbanks, AK, 99775-7750, USA
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