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Todd AC, Chumchal MM, Drenner RW, Allender CW, Barst BD, Capone MT, Degges AP, Hannappel MP, Perry CR, Peterson RA, Martinez TL, Schmeder IE, Williams TT, Willingham MG. Effects of Taxon and Body Size on Mercury Concentrations in Spiders from Two Rivers with Different Levels of Mercury Contamination: Implications for the Use of Riparian Spiders as Sentinels. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2024. [PMID: 39177425 DOI: 10.1002/etc.5968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 07/05/2024] [Accepted: 07/09/2024] [Indexed: 08/24/2024]
Abstract
Due to widespread atmospheric deposition of mercury (Hg), all aquatic food webs are contaminated with toxic methyl mercury (MeHg). At high concentrations, MeHg poses a health hazard to wildlife and humans. Spiders feeding in riparian habitats (hereafter referred to as riparian spiders) have been proposed as sentinels of MeHg contamination of aquatic systems. Riparian spiders are exposed to MeHg through their diets, and the concentration of MeHg in spiders is positively related to the proportion of MeHg-contaminated emergent aquatic insects in their diets. The use of spiders as sentinels is complex because their MeHg concentrations can vary, not only among ecosystems but also between different spider taxa and as a function of spider body size. The objective of the present study was to examine how the level of ecosystem contamination, spider taxon, and spider body size interact to influence MeHg concentrations in four genera of riparian spiders from two rivers with different levels of Hg contamination. We collected four genera of riparian spiders (Tetragnatha sp., Larinioides sp., Pardosa sp., and Rabidosa sp.) from two sites along both the Clear Fork of the Trinity River and the West Fork of the Trinity River (Fort Worth, TX, USA). We analyzed concentrations of MeHg in different body sizes of spiders from each genus. We found that MeHg contamination of the river ecosystem, spider taxon, and spider body size were important determinants of MeHg concentration in riparian spiders. The results suggest that any of the four taxa of riparian spiders from the present study could be used as sentinels of aquatic MeHg contamination, but they should not be used interchangeably because of the interdependence between the effects of ecosystem contamination level, spider taxon, and body size. Future studies utilizing riparian spiders as sentinels of biomagnifying aquatic contaminants (e.g., MeHg, polychlorinated biphenyls) should consider the potentially complex interaction effects between ecosystem contamination level, spider taxon, and spider body size. Environ Toxicol Chem 2024;00:1-7. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Affiliation(s)
- Andrew C Todd
- Biology Department, Texas Christian University, Fort Worth, Texas, USA
| | | | - Ray W Drenner
- Biology Department, Texas Christian University, Fort Worth, Texas, USA
| | - Chris W Allender
- Biology Department, Texas Christian University, Fort Worth, Texas, USA
| | - Benjamin D Barst
- Water and Environmental Research Center, University of Alaska Fairbanks, Fairbanks, Alaska, USA
- Department of Earth, Energy, and Environment, University of Calgary, Calgary, Alberta, Canada
| | - Morgan T Capone
- Biology Department, Texas Christian University, Fort Worth, Texas, USA
| | - Andrew P Degges
- Biology Department, Texas Christian University, Fort Worth, Texas, USA
| | - Madeline P Hannappel
- Department of Biological Sciences, University of North Texas, Denton, Texas, USA
| | - Cale R Perry
- Biology Department, Texas Christian University, Fort Worth, Texas, USA
| | - Robert A Peterson
- Biology Department, Texas Christian University, Fort Worth, Texas, USA
| | - Tori L Martinez
- Biology Department, Texas Christian University, Fort Worth, Texas, USA
| | - Iris E Schmeder
- Biology Department, Texas Christian University, Fort Worth, Texas, USA
| | - Tyler T Williams
- Biology Department, Texas Christian University, Fort Worth, Texas, USA
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2
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Evers DC, Ackerman JT, Åkerblom S, Bally D, Basu N, Bishop K, Bodin N, Braaten HFV, Burton MEH, Bustamante P, Chen C, Chételat J, Christian L, Dietz R, Drevnick P, Eagles-Smith C, Fernandez LE, Hammerschlag N, Harmelin-Vivien M, Harte A, Krümmel EM, Brito JL, Medina G, Barrios Rodriguez CA, Stenhouse I, Sunderland E, Takeuchi A, Tear T, Vega C, Wilson S, Wu P. Global mercury concentrations in biota: their use as a basis for a global biomonitoring framework. ECOTOXICOLOGY (LONDON, ENGLAND) 2024; 33:325-396. [PMID: 38683471 PMCID: PMC11213816 DOI: 10.1007/s10646-024-02747-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/06/2024] [Indexed: 05/01/2024]
Abstract
An important provision of the Minamata Convention on Mercury is to monitor and evaluate the effectiveness of the adopted measures and its implementation. Here, we describe for the first time currently available biotic mercury (Hg) data on a global scale to improve the understanding of global efforts to reduce the impact of Hg pollution on people and the environment. Data from the peer-reviewed literature were compiled in the Global Biotic Mercury Synthesis (GBMS) database (>550,000 data points). These data provide a foundation for establishing a biomonitoring framework needed to track Hg concentrations in biota globally. We describe Hg exposure in the taxa identified by the Minamata Convention: fish, sea turtles, birds, and marine mammals. Based on the GBMS database, Hg concentrations are presented at relevant geographic scales for continents and oceanic basins. We identify some effective regional templates for monitoring methylmercury (MeHg) availability in the environment, but overall illustrate that there is a general lack of regional biomonitoring initiatives around the world, especially in Africa, Australia, Indo-Pacific, Middle East, and South Atlantic and Pacific Oceans. Temporal trend data for Hg in biota are generally limited. Ecologically sensitive sites (where biota have above average MeHg tissue concentrations) have been identified throughout the world. Efforts to model and quantify ecosystem sensitivity locally, regionally, and globally could help establish effective and efficient biomonitoring programs. We present a framework for a global Hg biomonitoring network that includes a three-step continental and oceanic approach to integrate existing biomonitoring efforts and prioritize filling regional data gaps linked with key Hg sources. We describe a standardized approach that builds on an evidence-based evaluation to assess the Minamata Convention's progress to reduce the impact of global Hg pollution on people and the environment.
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Affiliation(s)
- David C Evers
- Biodiversity Research Institute, 276 Canco Road, Portland, ME, 04103, USA.
| | - Joshua T Ackerman
- U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive, Suite D, Dixon, CA, 95620, USA
| | | | - Dominique Bally
- African Center for Environmental Health, BP 826 Cidex 03, Abidjan, Côte d'Ivoire
| | - Nil Basu
- Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, QC, Canada
| | - Kevin Bishop
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Upsalla, Sweden
| | - Nathalie Bodin
- Research Institute for Sustainable Development Seychelles Fishing Authority, Victoria, Seychelles
| | | | - Mark E H Burton
- Biodiversity Research Institute, 276 Canco Road, Portland, ME, 04103, USA
| | - Paco Bustamante
- Littoral, Environnement et Sociétés (LIENSs), UMR 7266 CNRS La Rochelle Université, 2 Rue Olympe de Gouges, 17000, La Rochelle, France
| | - Celia Chen
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA
| | - John Chételat
- Environment and Cliamte Change Canada, National Wildlife Research Centre, Ottawa, ON, K1S 5B6, Canada
| | - Linroy Christian
- Department of Analytical Services, Dunbars, Friars Hill, St John, Antigua and Barbuda
| | - Rune Dietz
- Department of Ecoscience, Aarhus University, Arctic Research Centre (ARC), Department of Ecoscience, P.O. Box 358, DK-4000, Roskilde, Denmark
| | - Paul Drevnick
- Teck American Incorporated, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
| | - Collin Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR, 97331, USA
| | - Luis E Fernandez
- Sabin Center for Environment and Sustainability and Department of Biology, Wake Forest University, Winston-Salem, NC, 29106, USA
- Centro de Innovación Científica Amazonica (CINCIA), Puerto Maldonado, Madre de Dios, Peru
| | - Neil Hammerschlag
- Shark Research Foundation Inc, 29 Wideview Lane, Boutiliers Point, NS, B3Z 0M9, Canada
| | - Mireille Harmelin-Vivien
- Aix-Marseille Université, Université de Toulon, CNRS/INSU/IRD, Institut Méditerranéen d'Océanologie (MIO), UM 110, Campus de Luminy, case 901, 13288, Marseille, cedex 09, France
| | - Agustin Harte
- Basel, Rotterdam and Stockholm Conventions Secretariat, United Nations Environment Programme (UNEP), Chem. des Anémones 15, 1219, Vernier, Geneva, Switzerland
| | - Eva M Krümmel
- Inuit Circumpolar Council-Canada, Ottawa, Canada and ScienTissiME Inc, Barry's Bay, ON, Canada
| | - José Lailson Brito
- Universidade do Estado do Rio de Janeiro, Rua Sao Francisco Xavier, 524, Sala 4002, CEP 20550-013, Maracana, Rio de Janeiro, RJ, Brazil
| | - Gabriela Medina
- Director of Basel Convention Coordinating Centre, Stockholm Convention Regional Centre for Latin America and the Caribbean, Hosted by the Ministry of Environment, Montevideo, Uruguay
| | | | - Iain Stenhouse
- Biodiversity Research Institute, 276 Canco Road, Portland, ME, 04103, USA
| | - Elsie Sunderland
- Harvard University, Pierce Hall 127, 29 Oxford Street, Cambridge, MA, 02138, USA
| | - Akinori Takeuchi
- National Institute for Environmental Studies, Health and Environmental Risk Division, 16-2 Onogawa Tsukuba, Ibaraki, 305-8506, Japan
| | - Tim Tear
- Biodiversity Research Institute, 276 Canco Road, Portland, ME, 04103, USA
| | - Claudia Vega
- Centro de Innovaccion Cientifica Amazonica (CINCIA), Jiron Ucayali 750, Puerto Maldonado, Madre de Dios, 17001, Peru
| | - Simon Wilson
- Arctic Monitoring and Assessment Programme (AMAP) Secretariat, N-9296, Tromsø, Norway
| | - Pianpian Wu
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA
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3
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Willacker J, Eagles-Smith CA, Chandler JA, Naymik J, Myers R, Krabbenhoft DP. Reservoir Stratification Modulates the Influence of Impoundments on Fish Mercury Concentrations along an Arid Land River System. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:21313-21326. [PMID: 38051342 PMCID: PMC10734268 DOI: 10.1021/acs.est.3c04646] [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: 06/26/2023] [Revised: 10/20/2023] [Accepted: 10/25/2023] [Indexed: 12/07/2023]
Abstract
Impoundment is among the most common hydrologic alterations with impacts on aquatic ecosystems that can include effects on mercury (Hg) cycling. However, landscape-scale differences in Hg bioaccumulation between reservoirs and other habitats are not well characterized nor are the processes driving these differences. We examined total Hg (THg) concentrations of Smallmouth Bass (Micropterus dolomieu) collected from reservoir, tailrace, and free-flowing reaches along an 863 km segment of the Snake River, USA, a semiarid river with 22 impoundments along its course. Across three size-classes (putative 1-year-old, first reproductive, and harvestable sized fish), THg concentrations in reservoirs and tailraces averaged 76% higher than those in free-flowing segments. Among reservoirs, THg concentrations were highest in reservoirs with inconsistent stratification patterns, 47% higher than annually stratified, and 144% higher than unstratified reservoirs. Fish THg concentrations in tailraces immediately downstream of stratified reservoirs were higher than those below unstratified (38-130%) or inconsistently stratified (32-79%) reservoirs. Stratification regimes influenced the exceedance of fish and human health benchmarks, with 52-80% of fish from stratifying reservoirs and downstream tailraces exceeding a human consumption benchmark, compared to 6-17% where stratification did not occur. These findings suggest that impoundment and stratification play important roles in determining the patterns of Hg exposure risk across the landscape.
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Affiliation(s)
- James
J. Willacker
- U.S.
Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, Oregon 97331, United States
| | - Collin A. Eagles-Smith
- U.S.
Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, Oregon 97331, United States
| | - James A. Chandler
- Idaho
Power Company, 1221 West Idaho Street, Boise, Idaho 83702, United States
| | - Jesse Naymik
- Idaho
Power Company, 1221 West Idaho Street, Boise, Idaho 83702, United States
| | - Ralph Myers
- Idaho
Power Company, 1221 West Idaho Street, Boise, Idaho 83702, United States
| | - David P. Krabbenhoft
- U.S.
Geological Survey, Upper Midwest Water Science Center, 8505 Research Way, Middleton, Wisconsin 53562, United States
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4
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Peterson BD, Poulin BA, Krabbenhoft DP, Tate MT, Baldwin AK, Naymik J, Gastelecutto N, McMahon KD. Metabolically diverse microorganisms mediate methylmercury formation under nitrate-reducing conditions in a dynamic hydroelectric reservoir. THE ISME JOURNAL 2023; 17:1705-1718. [PMID: 37495676 PMCID: PMC10504345 DOI: 10.1038/s41396-023-01482-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 07/13/2023] [Accepted: 07/14/2023] [Indexed: 07/28/2023]
Abstract
Brownlee Reservoir is a mercury (Hg)-impaired hydroelectric reservoir that exhibits dynamic hydrological and geochemical conditions and is located within the Hells Canyon Complex in Idaho, USA. Methylmercury (MeHg) contamination in fish is a concern in the reservoir. While MeHg production has historically been attributed to sulfate-reducing bacteria and methanogenic archaea, microorganisms carrying the hgcA gene are taxonomically and metabolically diverse and the major biogeochemical cycles driving mercury (Hg) methylation are not well understood. In this study, Hg speciation and redox-active compounds were measured throughout Brownlee Reservoir across the stratified period in four consecutive years (2016-2019) to identify the location where and redox conditions under which MeHg is produced. Metagenomic sequencing was performed on a subset of samples to characterize the microbial community with hgcA and identify possible links between biogeochemical cycles and MeHg production. Biogeochemical profiles suggested in situ water column Hg methylation was the major source of MeHg. These profiles, combined with genome-resolved metagenomics focused on hgcA-carrying microbes, indicated that MeHg production occurs in this system under nitrate- or manganese-reducing conditions, which were previously thought to preclude Hg-methylation. Using this multidisciplinary approach, we identified the cascading effects of interannual variability in hydrology on the redox status, microbial metabolic strategies, abundance and metabolic diversity of Hg methylators, and ultimately MeHg concentrations throughout the reservoir. This work expands the known conditions conducive to producing MeHg and suggests that the Hg-methylation mitigation efforts by nitrate or manganese amendment may be unsuccessful in some locations.
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Affiliation(s)
- Benjamin D Peterson
- Department of Civil and Environmental Engineering, University of Wisconsin - Madison, Madison, WI, 53706, USA.
- Department of Bacteriology, University of Wisconsin - Madison, Madison, WI, 53706, USA.
- Department of Environmental Toxicology, University of California - Davis, Davis, CA, 95616, USA.
| | - Brett A Poulin
- Department of Environmental Toxicology, University of California - Davis, Davis, CA, 95616, USA
| | - David P Krabbenhoft
- U.S. Geological Survey, Upper Midwest Water Science Center, Mercury Research Laboratory, Madison, WI, 53726, USA
| | - Michael T Tate
- U.S. Geological Survey, Upper Midwest Water Science Center, Mercury Research Laboratory, Madison, WI, 53726, USA
| | - Austin K Baldwin
- U.S. Geological Survey, Idaho Water Science Center, Boise, ID, 83702, USA
| | | | | | - Katherine D McMahon
- Department of Civil and Environmental Engineering, University of Wisconsin - Madison, Madison, WI, 53706, USA
- Department of Bacteriology, University of Wisconsin - Madison, Madison, WI, 53706, USA
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5
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Lepak JM, Johnson BM, Hooten MB, Wolff BA, Hansen AG. Predicting sport fish mercury contamination in heavily managed reservoirs: Implications for human and ecological health. PLoS One 2023; 18:e0285890. [PMID: 37607193 PMCID: PMC10443864 DOI: 10.1371/journal.pone.0285890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 05/04/2023] [Indexed: 08/24/2023] Open
Abstract
Mercury (Hg) is a concerning contaminant due to its widespread distribution and tendency to accumulate to harmful concentrations in biota. We used a machine learning approach called random forest (RF) to test for different predictors of Hg concentrations in three species of Colorado reservoir sport fish. The RF approach indicated that the best predictors of 864 mm northern pike (Esox lucius) Hg concentrations were covariates related to salmonid stocking in each study system, while system-specific metrics related to productivity and forage base were the best predictors of Hg concentrations of 381 mm smallmouth bass (Micropterus dolomieu), and walleye (Sander vitreus). Protecting human and ecological health from Hg contamination requires an understanding of fish Hg concentrations and variability across the landscape and through time. The RF approach could be applied to identify potential areas/systems of concern, and predict whether sport fish Hg concentrations may change as a result of a variety of factors to help prioritize, focus, and streamline monitoring efforts to effectively and efficiently inform human and ecological health.
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Affiliation(s)
- Jesse M. Lepak
- Colorado Parks and Wildlife, Fort Collins, CO, United States of America
| | - Brett M. Johnson
- Department of Fish, Wildlife and Conservation Biology, Colorado State University, Fort Collins, CO, United States of America
| | - Mevin B. Hooten
- Department of Statistics and Data Sciences, College of Natural Sciences, The University of Texas at Austin, Austin, TX, United States of America
| | - Brian A. Wolff
- Department of Fish, Wildlife and Conservation Biology, Colorado State University, Fort Collins, CO, United States of America
| | - Adam G. Hansen
- Colorado Parks and Wildlife, Fort Collins, CO, United States of America
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Poulin BA, Tate MT, Ogorek J, Breitmeyer SE, Baldwin AK, Yoder AM, Harris R, Naymik J, Gastelecutto N, Hoovestol C, Larsen C, Myers R, Aiken GR, Krabbenhoft DP. Biogeochemical and hydrologic synergy control mercury fate in an arid land river-reservoir system. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2023; 25:912-928. [PMID: 37186129 DOI: 10.1039/d3em00032j] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Reservoirs in arid landscapes provide critical water storage and hydroelectric power but influence the transport and biogeochemical cycling of mercury (Hg). Improved management of reservoirs to mitigate the supply and uptake of bioavailable methylmercury (MeHg) in aquatic food webs will benefit from a mechanistic understanding of inorganic divalent Hg (Hg(II)) and MeHg fate within and downstream of reservoirs. Here, we quantified Hg(II), MeHg, and other pertinent biogeochemical constituents in water (filtered and associated with particles) at high temporal resolution from 2016-2020. This was done (1) at inflow and outflow locations of three successive hydroelectric reservoirs (Snake River, Idaho, Oregon) and (2) vertically and longitudinally within the first reservoir (Brownlee Reservoir). Under spring high flow, upstream inputs of particulate Hg (Hg(II) and MeHg) and filter-passing Hg(II) to Brownlee Reservoir were governed by total suspended solids and dissolved organic matter, respectively. Under redox stratified conditions in summer, net MeHg formation in the meta- and hypolimnion of Brownlee reservoir yielded elevated filter-passing and particulate MeHg concentrations, the latter exceeding 500 ng g-1 on particles. Simultaneously, the organic matter content of particulates increased longitudinally in the reservoir (from 9-29%) and temporally with stratified duration. In late summer and fall, destratification mobilized MeHg from the upgradient metalimnion and the downgradient hypolimnion of Brownlee Reservoir, respectively, resulting in downstream export of elevated filter-passing MeHg and organic-rich particles enriched in MeHg (up to 43% MeHg). We document coupled biogeochemical and hydrologic processes that yield in-reservoir MeHg accumulation and MeHg export in water and particles, which impacts MeHg uptake in aquatic food webs within and downstream of reservoirs.
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Affiliation(s)
- Brett A Poulin
- Department of Environmental Toxicology, University of California, Davis, USA.
| | - Michael T Tate
- U.S. Geological Survey, Upper Midwest Water Science Center, USA
| | - Jacob Ogorek
- U.S. Geological Survey, Upper Midwest Water Science Center, USA
| | | | | | - Alysa M Yoder
- U.S. Geological Survey, Idaho Water Science Center, USA
| | - Reed Harris
- Reed Harris Environmental Ltd, Toronto, Canada
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7
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Eckley CS, Eagles-Smith C, Luxton TP, Hoffman J, Janssen S. Using mercury stable isotope fractionation to identify the contribution of historical mercury mining sources present in downstream water, sediment and fish. FRONTIERS IN ENVIRONMENTAL CHEMISTRY 2023; 4:1096199. [PMID: 37323923 PMCID: PMC10269370 DOI: 10.3389/fenvc.2023.1096199] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Ecosystems downstream of mercury (Hg) contaminated sites can be impacted by both localized releases as well as Hg deposited to the watershed from atmospheric transport. Identifying the source of Hg in water, sediment, and fish downstream of contaminated sites is important for determining the effectiveness of source-control remediation actions. This study uses measurements of Hg stable isotopes in soil, sediment, water, and fish to differentiate between Hg from an abandoned Hg mine from non-mine-related sources. The study site is located within the Willamette River watershed (Oregon, United States), which includes free-flowing river segments and a reservoir downstream of the mine. The concentrations of total-Hg (THg) in the reservoir fish were 4-fold higher than those further downstream (>90 km) from the mine site in free-flowing sections of the river. Mercury stable isotope fractionation analysis showed that the mine tailings (δ202Hg: -0.36‰ ± 0.03‰) had a distinctive isotopic composition compared to background soils (δ202Hg: -2.30‰ ± 0.25‰). Similar differences in isotopic composition were observed between stream water that flowed through the tailings (particulate bound δ202Hg: -0.58‰; dissolved: -0.91‰) versus a background stream (particle-bound δ202Hg: -2.36‰; dissolved: -2.09‰). Within the reservoir sediment, the Hg isotopic composition indicated that the proportion of the Hg related to mine-release increased with THg concentrations. However, in the fish samples the opposite trend was observed-the degree of mine-related Hg was lower in fish with the higher THg concentrations. While sediment concentrations clearly show the influence of the mine, the relationship in fish is more complicated due to differences in methylmercury (MeHg) formation and the foraging behavior of different fish species. The fish tissue δ13C and Δ199Hg values indicate that there is a higher influence of mine-sourced Hg in fish feeding in a more sediment-based food web and less so in planktonic and littoral-based food webs. Identifying the relative proportion of Hg from local contaminated site can help inform remediation decisions, especially when the relationship between total Hg concentrations and sources do not show similar covariation between abiotic and biotic media.
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Affiliation(s)
| | - Collin Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, OR, United States
| | - Todd P. Luxton
- US EPA ORD, Center for Environmental Solutions and Emergency Response, Cincinnati, OH, United States
| | - Joel Hoffman
- U.S. EPA Office of Research and Development, Center for Computational Toxicology and Exposure, Great Lakes Toxicology and Ecology Division, Duluth, MN, United States
| | - Sarah Janssen
- U.S. Geological Survey, Mercury Research Lab, Upper Midwest Water Science Center, Madison, WI, United States
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8
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Millard G, Eckley CS, Luxton TP, Krabbenhoft D, Goetz J, McKernan J, DeWild J. Evaluating the influence of seasonal stratification on mercury methylation rates in the water column and sediment in a contaminated section of a western U.S.A. reservoir. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 316:120485. [PMID: 36279994 PMCID: PMC10259237 DOI: 10.1016/j.envpol.2022.120485] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 10/14/2022] [Accepted: 10/17/2022] [Indexed: 06/14/2023]
Abstract
Mercury methylation frequently occurs at the active oxic/anoxic boundary between the sediment bed and water column of lakes and reservoirs. Previous studies suggest that the predominant mercury methylation zone moves to the water column during periods of stratification and that high potential methylation rates (Km) in sediment require oxygenated overlying water. However, simultaneous measurements of methylmercury (MeHg) production in both the sediment and water column remain limited. Understanding the relative importance of sediment versus water column methylation and the impact of seasonal stratification on these processes has important implications for managing MeHg production. This study measured Km and potential demethylation rates (Kdm) using stable isotope tracers of unfiltered inorganic mercury and MeHg in sediments and water of the littoral and profundal zones of a shallow branch of the Nacimiento Reservoir in California's central coastal range. Field sampling was conducted once during winter (well-mixed/oxygenated conditions) and once during late summer (thermally stratified/anoxic conditions). The results showed very high ambient MeHg concentrations in hypolimnetic waters (up to 7.5 ng L-1; 79% MeHg/total Hg). During late summer, littoral sediments had higher Km (0.024 day-1) compared to profundal sediments (0.013 day-1). Anoxic water column Km were of similar magnitude to Km in the sediment (0.03 day-1). Following turnover, profundal sediment Km did not change significantly, but water column Km became insignificant. Summer and winter sediment Kdm were higher in profundal (2.35, 3.54 day-1, respectively) compared to the littoral sediments (0.52, 2.56 day-1, respectively). When modelled, Km in the water column could account for approximately 40% of the hypolimnetic MeHg. Our modelling results show that the remaining MeHg in the hypolimnion could originate from the profundal sediment. While further study is needed, these results suggest that addressing methylation in the water column and profundal sediment are of equal importance to any remediation strategy.
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Affiliation(s)
- Geoffrey Millard
- U.S.A. Environmental Protection Agency, Office of Research and Development, 26 W Martin Luther King Dr, Cincinnati, OH, 45220, USA.
| | - Chris S Eckley
- U.S.A. Environmental Protection Agency, Region 10, 1200 Sixth Avenue, Suite 155, Seattle WA, 98101, USA.
| | - Todd P Luxton
- U.S.A. Environmental Protection Agency, Office of Research and Development, 26 W Martin Luther King Dr, Cincinnati, OH, 45220, USA.
| | - David Krabbenhoft
- U.S.A. Geological Survey, Mercury Research Laboratory, 2280 Woodale Drive, Mounds View MN, 55112, USA.
| | - Jennifer Goetz
- U.S.A. Environmental Protection Agency, Office of Research and Development, 26 W Martin Luther King Dr, Cincinnati, OH, 45220, USA.
| | - John McKernan
- U.S.A. Environmental Protection Agency, Office of Research and Development, 26 W Martin Luther King Dr, Cincinnati, OH, 45220, USA.
| | - John DeWild
- U.S.A. Geological Survey, Mercury Research Laboratory, 2280 Woodale Drive, Mounds View MN, 55112, USA.
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9
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Drenner RW, Chumchal MM, Adams KJ, Seymour RD. Effect of Land Cover on Ecoregion-Scale Spatial Patterns of Mercury Contamination of Largemouth Bass in the Southeastern United States. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2022; 41:2386-2394. [PMID: 35975571 DOI: 10.1002/etc.5426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/03/2021] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
Consumption of methylmercury (MeHg)-contaminated fish is the primary source of MeHg in humans and poses a hazard to human health. Because of widespread atmospheric deposition of inorganic mercury (IHg), all water bodies in the United States have been contaminated with Hg. In aquatic ecosystems, IHg is converted to MeHg, which biomagnifies, reaching high concentrations in piscivorous fish. It is not possible for governmental agencies to monitor fish from every waterbody to determine if concentrations of MeHg in fish are hazardous to human health. To help government agencies focus their monitoring efforts, it is critical that we develop the ability to predict regions where waterbodies are most likely to contain fish with hazardous concentrations of MeHg. The objective of the present study was to examine the relationship between MeHg contamination of largemouth bass (Micropterus salmoides), a popular piscivorous gamefish, and land cover in 24 ecoregions across 15 states in the southeastern United States. In our study we demonstrate for the first time that 72% of the variance in average concentrations of MeHg in largemouth bass between ecoregions of the southeastern United States can be explained by the percentage coverage by evergreen forests, emergent herbaceous wetlands, and pasture/hay. Land cover determines the sensitivity of freshwater systems to atmospheric IHg deposition, and the present study suggests that at the ecoregion scale, MeHg bioaccumulation in piscivorous gamefish, and ultimately the health hazard that these MeHg-contaminated fish pose to humans, can be in part predicted by land-cover type. Environ Toxicol Chem 2022;41:2386-2394. © 2022 SETAC.
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Affiliation(s)
- Ray W Drenner
- Biology Department, Texas Christian University, Fort Worth, Texas, USA
| | | | - Kimberly J Adams
- Biology Department, Texas Christian University, Fort Worth, Texas, USA
| | - Ryan D Seymour
- Biology Department, Texas Christian University, Fort Worth, Texas, USA
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10
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Mills N, Weber MJ, Cashatt D, Pierce CL, Dixon P. Factors related to fish mercury concentrations in Iowa lakes. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:721. [PMID: 36056241 DOI: 10.1007/s10661-022-10427-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 08/30/2022] [Indexed: 06/15/2023]
Abstract
Mercury contamination in aquatic ecosystems is a global concern due to the health risks of consuming contaminated fishes. Fish mercury concentrations are influenced by a range of biotic and abiotic factors that vary among regions, but these complex interactions are difficult to disentangle. We collected bluegill (Lepomis macrochirus), white and black crappie (Pomoxis annularis; P. nigromaculatus), largemouth bass (Micropterus salmoides), walleye (Sander vitreus), muskellunge (Esox masquinongy), and northern pike (E. lucius) from waterbodies throughout Iowa and analyzed them for mercury concentrations. We used land use, water chemistry, and fish characteristics to explain variation in mercury concentrations among and within systems. Mercury concentrations were generally low and undetectable (< 0.05 mg/kg) in 43% of fish analyzed. Detected mercury concentrations were highest in largemouth bass, muskellunge, northern pike, and walleye, lowest in black and white crappie and bluegill, and positively related to fish length and age. Mean lake depth, pH, watershed area to lake area ratio, and percent of watershed as open water were positively related to fish mercury concentrations whereas lake area and percent of watershed as agriculture, developed, forested, and grassland were negatively related to mercury concentrations. Additionally, mercury concentrations were higher in shallow natural lakes compared to other lake types. Our results indicate fish mercury concentrations are lower in Iowa lakes compared to other regions. Models we developed in this study can be used to identify other waterbodies that may have elevated mercury concentrations that can guide fish mercury monitoring programs.
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Affiliation(s)
- Nathan Mills
- Department of Natural Resource Ecology and Management, Iowa State University, 339 Science Hall II, Ames, IA, 50011, USA
| | - Michael J Weber
- Department of Natural Resource Ecology and Management, Iowa State University, 339 Science Hall II, Ames, IA, 50011, USA.
| | - Darcy Cashatt
- Iowa Department of Natural Resources, 15053 Hatchery Place, Moravia, IA, USA
| | - Clay L Pierce
- Department of Natural Resource Ecology and Management, Iowa State University, 339 Science Hall II, Ames, IA, 50011, USA
| | - Philip Dixon
- Department of Statistics, Iowa State University, Ames, IA, 50011, USA
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11
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Drenner RW, Chumchal MM, Gaul SP, Hembrough MT, Khan AM, Rolfe IM, Wallace GR, Hannappel MP. Sentinel Riparian Spiders Predict Mercury Contamination of Riverine Fish. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2022; 41:1297-1303. [PMID: 35156228 DOI: 10.1002/etc.5307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 12/28/2021] [Accepted: 02/03/2022] [Indexed: 06/14/2023]
Abstract
Mercury (Hg) is a widespread and toxic environmental contaminant. It is challenging to determine the level of Hg contamination of food chains and fish within the millions of water bodies in the United States. Mercury contamination can vary 10-fold between ecosystems, even those in the same region. Therefore, aquatic ecosystems need to be individually monitored for Hg contamination to determine which ecosystems are most contaminated and pose the greatest risk to human and wildlife health. One approach to monitoring Hg is to use sentinel species, defined as biological monitors that accumulate a contaminant in their tissues without significant adverse effects. Riparian spiders such as long-jawed orb weavers (Tetragnathidae) have been proposed as sentinels of persistent bioavailable contaminants, like Hg, in aquatic systems. Long-jawed orb weavers feed on emergent aquatic insects and have concentrations of Hg that reflect levels of Hg contamination in the aquatic food web. Previous studies have documented elevated contaminant concentrations in long-jawed orb weavers from shorelines of aquatic ecosystems, suggesting that they could be used as sentinels of chemical contaminants in aquatic ecosystems. We demonstrate for the first time that long-jawed orb weavers can be used as sentinels to identify aquatic systems that contain fish with elevated concentrations of Hg. Environ Toxicol Chem 2022;41:1297-1303. © 2022 SETAC.
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Affiliation(s)
- Ray W Drenner
- Department of Biology, Texas Christian University, Fort Worth, Texas, USA
| | - Matthew M Chumchal
- Department of Biology, Texas Christian University, Fort Worth, Texas, USA
| | - Simon P Gaul
- Department of Biology, Texas Christian University, Fort Worth, Texas, USA
| | | | - Amal M Khan
- Department of Biology, Texas Christian University, Fort Worth, Texas, USA
| | - Ian M Rolfe
- Department of Biology, Texas Christian University, Fort Worth, Texas, USA
| | - Garrett R Wallace
- Department of Biology, Texas Christian University, Fort Worth, Texas, USA
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12
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Ekblad C, Eulaers I, Schulz R, Stjernberg T, Søndergaard J, Zubrod J, Laaksonen T. Spatial and dietary sources of elevated mercury exposure in white-tailed eagle nestlings in an Arctic freshwater environment. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 290:117952. [PMID: 34425374 DOI: 10.1016/j.envpol.2021.117952] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 08/09/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
Human-induced mercury (Hg) contamination is of global concern and its effects on wildlife remain of high concern, especially in environmental hotspots such as inland aquatic ecosystems. Mercury biomagnifies through the food web resulting in high exposure in apex predators, such as the white-tailed eagle (Haliaeetus albicilla), making them excellent sentinel species for environmental Hg contamination. An expanding population of white-tailed eagles is inhabiting a sparsely populated inland area in Lapland, northern Finland, mainly around two large reservoirs flooded 50 years ago. As previous preliminary work revealed elevated Hg levels in this population, we measured Hg exposure along with dietary proxies (δ13C and δ15N) in body feathers collected from white-tailed eagle nestlings in this area between 2007 and 2018. Mercury concentrations were investigated in relation to territory characteristics, proximity to the reservoirs and dietary ecology as potential driving factors of Hg contamination. Mercury concentrations in the nestlings (4.97-31.02 μg g-1 dw) were elevated, compared to earlier reported values in nestlings from the Finnish Baltic coast, and exceeded normal background levels (≤5.00 μg g-1) while remaining below the tentative threshold of elevated risk for Hg exposure mediated health effect (>40.00 μg g-1). The main drivers of Hg contamination were trophic position (proxied by δ15N), the dietary proportion of the predatory fish pike (Esox lucius), and the vicinity to the Porttipahta reservoir. We also identified a potential evolutionary trap, as increased intake of the preferred prey, pike, increases exposure. All in all, we present results for poorly understood freshwater lake environments and show that more efforts should be dedicated to further unravel potentially complex pathways of Hg exposure to wildlife.
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Affiliation(s)
- Camilla Ekblad
- Section of Ecology, Department of Biology, University of Turku, 20014, Turku, Finland.
| | - Igor Eulaers
- Department of Bioscience, Aarhus University, Frederiksborgvej 399, PO Box 358, DK-4000, Roskilde, Denmark
| | - Ralf Schulz
- IES Landau, Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, DE-76829, Landau, Germany
| | - Torsten Stjernberg
- Finnish Museum of Natural History, University of Helsinki, PO Box 17, FI-00014, Helsinki, Finland
| | - Jens Søndergaard
- Department of Bioscience, Aarhus University, Frederiksborgvej 399, PO Box 358, DK-4000, Roskilde, Denmark
| | - Jochen Zubrod
- IES Landau, Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, DE-76829, Landau, Germany
| | - Toni Laaksonen
- Section of Ecology, Department of Biology, University of Turku, 20014, Turku, Finland
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13
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Eckley CS, Luxton TP, Knightes CD, Shah V. Methylmercury Production and Degradation under Light and Dark Conditions in the Water Column of the Hells Canyon Reservoirs, USA. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2021; 40:1829-1839. [PMID: 33729607 PMCID: PMC8745031 DOI: 10.1002/etc.5041] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 02/28/2021] [Accepted: 03/09/2021] [Indexed: 05/28/2023]
Abstract
Methylmercury (MeHg) is a highly toxic form of mercury that can bioaccumulate in fish tissue. Methylmercury is produced by anaerobic bacteria, many of which are also capable of MeHg degradation. In addition, demethylation in surface waters can occur via abiotic sunlight-mediated processes. The goal of the present study was to understand the relative importance of microbial Hg methylation/demethylation and abiotic photodemethylation that govern the mass of MeHg within an aquatic system. The study location was the Hells Canyon complex of 3 reservoirs on the Idaho-Oregon border, USA, that has fish consumption advisories as a result of elevated MeHg concentrations. Our study utilized stable isotope addition experiments to trace MeHg formation and degradation within the water column of the reservoirs to understand the relative importance of these processes on the mass of MeHg using the Water Quality Analysis Simulation Program. The results showed that rates of MeHg production and degradation within the water column were relatively low (<0.07 d-1 ) but sufficient to account for most of the MeHg observed with the system. Most MeHg production within the water column appeared to occur in the spring when much of the water column was in the processes of becoming anoxic. In the surface waters, rates of photodemethylation were relatively large (up to -0.25 d-1 ) but quickly decreased at depths >0.5 m below the surface. These results can be used to identify the relative importance of MeHg processes that can help guide reservoir management decisions. Environ Toxicol Chem 2021;40:1829-1839. © 2021 SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.
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Affiliation(s)
- Chris S. Eckley
- US Environmental Protection Agency, Region-10, Seattle, Washington
| | - Todd P. Luxton
- Office of Research and Development, US Environmental Protection Agency, Cincinnati, Ohio
| | - Christopher D. Knightes
- Office of Research and Development, US Environmental Protection Agency, Narragansett, Rhode Island
| | - Vishal Shah
- College of the Sciences and Mathematics, West Chester University, West Chester, Pennsylvania, USA
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14
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Millera Ferriz L, Ponton DE, Storck V, Leclerc M, Bilodeau F, Walsh DA, Amyot M. Role of organic matter and microbial communities in mercury retention and methylation in sediments near run-of-river hydroelectric dams. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 774:145686. [PMID: 33609815 DOI: 10.1016/j.scitotenv.2021.145686] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 01/08/2021] [Accepted: 02/03/2021] [Indexed: 06/12/2023]
Abstract
Run-of-river power plants (RoRs) are expected to triple in number over the next decades in Canada. These structures are not anticipated to considerably promote the mobilization and transport of mercury (Hg) and its subsequent microbial transformation to methylmercury (MeHg), a neurotoxin able to biomagnify in food webs up to humans. To test whether construction of RoRs had an effect on Hg transport and transformation, we studied Hg and MeHg concentrations, organic matter contents and methylating microbial community abundance and composition in the sediments of a section of the St. Maurice River (Quebec, Canada). This river section has been affected by the construction of two RoR dams and its watershed has been disturbed by a forest fire, logging, and the construction of wetlands. Higher total Hg (THg) and MeHg concentrations were observed in the surface sediments of the flooded sites upstream of the RoRs. These peaks in THg and MeHg were correlated with organic matter proportions in the sediments (r2 = 0.87 and 0.82, respectively). In contrast, the proportion of MeHg, a proxy for methylation potential, was best explained by the carbon to nitrogen ratio suggesting the importance of terrigenous organic matter as labile substrate for Hg methylation in this system. Metagenomic analysis of Hg-methylating communities based on the hgcA functional gene marker indicated an abundance of methanogens, sulfate reducers and fermenters, suggesting that these metabolic guilds may be primary Hg methylators in these surface sediments. We propose that RoR pondages act as traps for sediments, organic matter and Hg, and that this retention can be amplified by other disturbances of the watershed such as forest fire and logging. RoR flooded sites can be conducive to Hg methylation in sediments and may act as gateways for bioaccumulation and biomagnification of MeHg along food webs, particularly in disturbed watersheds.
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Affiliation(s)
- L Millera Ferriz
- Département de sciences biologiques, Université de Montréal, Montreal H2V 2S9, QC, Canada; Biology Department, Concordia University, Montreal H4B 1R6, QC, Canada; GRIL, Groupe de Recherche Interuniversitaire en Limnologie, Département de sciences biologiques, Université de Montréal, Campus MIL, Montreal H3C 3J7, QC, Canada
| | - D E Ponton
- Département de sciences biologiques, Université de Montréal, Montreal H2V 2S9, QC, Canada; GRIL, Groupe de Recherche Interuniversitaire en Limnologie, Département de sciences biologiques, Université de Montréal, Campus MIL, Montreal H3C 3J7, QC, Canada
| | - V Storck
- Département de sciences biologiques, Université de Montréal, Montreal H2V 2S9, QC, Canada; Biology Department, Concordia University, Montreal H4B 1R6, QC, Canada
| | - M Leclerc
- Département de sciences biologiques, Université de Montréal, Montreal H2V 2S9, QC, Canada; GRIL, Groupe de Recherche Interuniversitaire en Limnologie, Département de sciences biologiques, Université de Montréal, Campus MIL, Montreal H3C 3J7, QC, Canada
| | - F Bilodeau
- Hydro-Québec Production, Environment Department, Montreal, QC, Canada
| | - D A Walsh
- Biology Department, Concordia University, Montreal H4B 1R6, QC, Canada; GRIL, Groupe de Recherche Interuniversitaire en Limnologie, Département de sciences biologiques, Université de Montréal, Campus MIL, Montreal H3C 3J7, QC, Canada
| | - M Amyot
- Département de sciences biologiques, Université de Montréal, Montreal H2V 2S9, QC, Canada; GRIL, Groupe de Recherche Interuniversitaire en Limnologie, Département de sciences biologiques, Université de Montréal, Campus MIL, Montreal H3C 3J7, QC, Canada.
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15
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Larson JH, Maki RP, Christensen VG, Hlavacek EJ, Sandheinrich MB, LeDuc JF, Kissane C, Knights BC. Mercury and water level management in lakes of northern Minnesota. Ecosphere 2021. [DOI: 10.1002/ecs2.3465] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- James H. Larson
- U.S. Geological Survey Upper Midwest Environmental Sciences Center La Crosse Wisconsin54603USA
| | - Ryan P. Maki
- National Park Service Voyageurs National Park International Falls Minnesota56649USA
| | | | - Enrika J. Hlavacek
- U.S. Geological Survey Upper Midwest Environmental Sciences Center La Crosse Wisconsin54603USA
| | - Mark B. Sandheinrich
- River Studies Center University of Wisconsin‐La Crosse La Crosse Wisconsin54601USA
| | - Jaime F. LeDuc
- National Park Service Voyageurs National Park International Falls Minnesota56649USA
| | - Claire Kissane
- National Park Service Voyageurs National Park International Falls Minnesota56649USA
| | - Brent C. Knights
- U.S. Geological Survey Upper Midwest Environmental Sciences Center La Crosse Wisconsin54603USA
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16
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Hebert CE, Chételat J, Beck R, Dolgova S, Fordy K, Kirby P, Martin P, Rabesca M. Inter-annual variation of mercury in aquatic bird eggs and fish from a large subarctic lake under a warming climate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 766:144614. [PMID: 33421792 DOI: 10.1016/j.scitotenv.2020.144614] [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: 09/30/2020] [Revised: 12/14/2020] [Accepted: 12/16/2020] [Indexed: 06/12/2023]
Abstract
Understanding changes in environmental mercury concentrations is important for assessing the risk to human and wildlife populations from this potent toxicant. Here, we use herring gull (Larus argentatus) eggs to evaluate temporal changes in total mercury (THg) availability from two locations on Great Slave Lake (GSL), Northwest Territories, Canada. Egg THg concentrations increased through time, but this change was due to shifts in gull diets. Stable nitrogen isotopes allowed adjustment of egg THg concentrations for dietary changes. Diet-adjusted egg THg concentrations showed no long-term trend. Consistent with that result, new statistical analysis of THg concentrations in three species of GSL fish showed minor or no temporal changes. Although a long-term trend was absent, inter-year differences in adjusted egg THg concentrations persisted. Contributions of environmental variables (i.e., river flow, lake level, air temperature, precipitation, and wildfire) to these differences were investigated. Egg THg concentrations were greater following years of lower lake levels and greater wildfire extent. Lake level could have affected mercury methylation. Increased wildfire could have enhanced terrestrial Hg releases to the atmosphere where it was transported long distances to GSL. Climate change may increase wildfire extent with impacts on Hg bioaccumulation in northern ecosystems. Egg Hg levels reported here are unlikely to pose health risks to gulls, but in light of ongoing environmental change, monitoring should continue. Our study emphasizes the importance of ancillary datasets in elucidating Hg trends; such information will be critical for evaluating the effectiveness of Hg mitigation strategies implemented as part of the Minamata Convention.
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Affiliation(s)
- Craig E Hebert
- Environment and Climate Change Canada, Science and Technology Branch, Ecotoxicology and Wildlife Health Division, National Wildlife Research Centre, Ottawa, ON K1S 5B6, Canada.
| | - John Chételat
- Environment and Climate Change Canada, Science and Technology Branch, Ecotoxicology and Wildlife Health Division, National Wildlife Research Centre, Ottawa, ON K1S 5B6, Canada
| | - Roger Beck
- Fort Resolution Métis Council, Fort Resolution, NT X0E 0M0, Canada
| | - Svetlana Dolgova
- Environment and Climate Change Canada, Science and Technology Branch, Ecotoxicology and Wildlife Health Division, National Wildlife Research Centre, Ottawa, ON K1S 5B6, Canada
| | - Kathleen Fordy
- Deninu Kųę́ First Nation, Fort Resolution, NT X0E 0M0, Canada
| | - Patrick Kirby
- Environment and Climate Change Canada, Science and Technology Branch, Landscape Science and Technology Division, National Wildlife Research Centre, Ottawa, ON K1S 5B6, Canada
| | - Pamela Martin
- Environment and Climate Change Canada, Science and Technology Branch, Ecotoxicology and Wildlife Health Division, Burlington, ON L7R 4A6, Canada
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17
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Yin D, Peng F, He T, Xu Y, Wang Y. Ecological risks of heavy metals as influenced by water-level fluctuations in a polluted plateau wetland, southwest China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 742:140319. [PMID: 32634688 DOI: 10.1016/j.scitotenv.2020.140319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 06/11/2023]
Abstract
The Caohai wetland, one of karst plateau wetlands in southwest China, is given more attention due to the serious heavy metal (HM) pollution from artisanal zinc smelting activities. A natural hydrological change has caused this wetland to form a water-level fluctuating zone. This raises a question of whether such an area has elevated HM risks to the aquatic environment, and it was explored by a field investigation and biological exposure experiment. The results showed that Caohai sediment properties were significantly altered by water-level fluctuation, and the permanently inundated sediment had obviously higher organic matter (SOM) concentrations (32.62 ± 9.37%), humification levels (ratio of C to H, 6.81 ± 0.97), and Fe oxide fractions (12.29 ± 3.17%) than seasonally inundated sediment (4.94 ± 2.25%, 1.33 ± 0.75, and 8.72 ± 1.87%, respectively). These significantly enhanced the competition and retention, resulting in the increased accumulation, whereas reduced bioavailability of HMs. In comparison, the mean bioaccumulation capacity of Zn, Pb and Cd by wild benthos at the seasonally inundated area respectively increased by 2, 11 and 20 times higher than that at the permanently inundated area, which was further verified in the biological incubation experiment. Our results suggest that hydraulic fluctuation can greatly shape the sediment properties to increase the ecological risks of HMs to organisms.
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Affiliation(s)
- Deliang Yin
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Resources and Environment, Guizhou University, Guiyang 550025, China; Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang 550025, China
| | - Fengcheng Peng
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China
| | - Tianrong He
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Resources and Environment, Guizhou University, Guiyang 550025, China; Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang 550025, China.
| | - Yiyuan Xu
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Resources and Environment, Guizhou University, Guiyang 550025, China
| | - Yongmin Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
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18
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Peterson SH, Ackerman JT, Hartman CA, Casazza ML, Feldheim CL, Herzog MP. Mercury exposure in mammalian mesopredators inhabiting a brackish marsh. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 273:115808. [PMID: 33497946 DOI: 10.1016/j.envpol.2020.115808] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 09/18/2020] [Accepted: 10/09/2020] [Indexed: 06/12/2023]
Abstract
Bioaccumulation of environmental contaminants in mammalian predators can serve as an indicator of ecosystem health. We examined mercury concentrations of raccoons (Procyon lotor; n = 37 individuals) and striped skunks (Mephitis mephitis; n = 87 individuals) in Suisun Marsh, California, a large brackish marsh that is characterized by contiguous tracts of tidal marsh and seasonally impounded wetlands. Mean (standard error; range) total mercury concentrations in adult hair grown from 2015 to 2018 were 28.50 μg/g dw (3.05 μg/g dw; range: 4.46-81.01 μg/g dw) in raccoons and 4.85 μg/g dw (0.54 μg/g dw; range: 1.53-27.02 μg/g dw) in striped skunks. We reviewed mammalian hair mercury concentrations in the literature and raccoon mercury concentrations in Suisun Marsh were among the highest observed for wild mammals. Although striped skunk hair mercury concentrations were 83% lower than raccoons, they were higher than proposed background levels for mercury in mesopredator hair (1-5 μg/g). Hair mercury concentrations in skunks and raccoons were not related to animal size, but mercury concentrations were higher in skunks in poorer body condition. Large inter-annual differences in hair mercury concentrations suggest that methylmercury exposure to mammalian predators varied among years. Mercury concentrations of raccoon hair grown in 2017 were 2.7 times greater than hair grown in 2015, 1.7 times greater than hair grown in 2016, and 1.6 times greater than hair grown in 2018. Annual mean raccoon and skunk hair mercury concentrations increased with wetland habitat area. Furthermore, during 2017, raccoon hair mercury concentrations increased with the proportion of raccoon home ranges that was wetted habitat, as quantified using global positioning system (GPS) collars. The elevated mercury concentrations we observed in raccoons and skunks suggest that other wildlife at similar or higher trophic positions may also be exposed to elevated methylmercury bioaccumulation in brackish marshes.
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Affiliation(s)
- Sarah H Peterson
- U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive Suite D, Dixon, CA, 95620, USA.
| | - Joshua T Ackerman
- U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive Suite D, Dixon, CA, 95620, USA
| | - C Alex Hartman
- U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive Suite D, Dixon, CA, 95620, USA
| | - Michael L Casazza
- U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive Suite D, Dixon, CA, 95620, USA
| | - Cliff L Feldheim
- California Department of Water Resources, 3500 Industrial Blvd #131, West Sacramento, CA 95691, USA
| | - Mark P Herzog
- U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive Suite D, Dixon, CA, 95620, USA
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19
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Jackson AK, Eagles-Smith CA, Emery C. Spatial variation in aquatic invertebrate and riparian songbird mercury exposure across a river-reservoir system with a legacy of mercury contamination. ECOTOXICOLOGY (LONDON, ENGLAND) 2020; 29:1195-1204. [PMID: 31056730 DOI: 10.1007/s10646-019-02043-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/08/2019] [Indexed: 06/09/2023]
Abstract
Mercury (Hg) loading and methylation in aquatic systems causes a variety of deleterious effects for fish and wildlife populations. Relatively little research has focused on Hg movement into riparian food webs and how this is modulated by habitat characteristics. This study characterized differences in Hg exposure in aquatic invertebrates and riparian songbirds across a large portion of the Willamette River system in western Oregon, starting at a Hg-contaminated Superfund site in the headwaters (Black Butte Hg Mine) and including a reservoir known to methylate Hg (Cottage Grove Reservoir), all downstream reaches (Coast Fork and Willamette River) and off-channel wetland complexes (Willamette Valley National Wildlife Refuge Complex). After accounting for year, date, and site differences in a mixed effects model, MeHg concentrations in aquatic invertebrates varied spatially among habitat categories and invertebrate orders. Similarly, THg in songbird blood varied by among habitat categories and bird species. The highest Hg concentrations occurred near the Hg mine, but Hg did not decline linearly with distance from the source of contamination. Birds were consistently elevated in Hg in habitats commonly associated with enhanced MeHg production, such as backwater or wetlands. We found a positive but weak correlation between aquatic invertebrate MeHg concentrations and songbird THg concentrations on a site-specific basis. Our findings suggest that Hg risk to riparian songbirds can extend beyond point-source contaminated areas, highlighting the importance of assessing exposure in surrounding habitats where methylmercury production may be elevated, such as reservoirs and wetlands.
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Affiliation(s)
- Allyson K Jackson
- Department of Environmental Studies, Purchase College SUNY, 735 Anderson Hill Road, Purchase, NY, 10577, USA.
- Department of Fisheries and Wildlife, Oregon State University, 104 Nash Hall, Corvallis, OR, 97331, USA.
| | - Collin A Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR, 97331, USA
| | - Colleen Emery
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR, 97331, USA
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20
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Winder VL, Anteau MJ, Fisher MR, Wilcox MK, Igl LD, Ackerman JT. Wetland water-management may influence mercury bioaccumulation in songbirds and ducks at a mercury hotspot. ECOTOXICOLOGY (LONDON, ENGLAND) 2020; 29:1229-1239. [PMID: 31902053 DOI: 10.1007/s10646-019-02143-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/25/2019] [Indexed: 06/10/2023]
Abstract
Mercury is a persistent, biomagnifying contaminant that can cause negative behavioral, immunological, and reproductive effects in wildlife and human populations. We examined the role of wetland water-management on mercury bioaccumulation in songbirds and ducks at Kellys Slough National Wildlife Refuge Complex, near Grand Forks, North Dakota USA. We assessed mercury concentrations in blood of wetland-foraging songbirds (80 common yellowthroats [Geothlypis trichas] and 14 Nelson's sparrows [Ammospiza nelsoni]) and eggs of upland-nesting ducks (28 gadwall [Mareca strepera], 19 blue-winged teal [Spatula discors], and 13 northern shoveler [S. clypeta]) across four wetland water-management classifications. Nelson's sparrow blood mercury concentrations were elevated (mean: 1.00 µg/g ww; 95% CL: 0.76-1.31) and similar to those reported 6 years previously. Mercury in songbird blood and duck eggs varied among wetland water-management classifications. Songbirds and ducks had 67% and 49% lower mercury concentrations, respectively, when occupying wetlands that were drawn down with water flow compared to individuals occupying isolated-depressional wetlands with no outflow. Additionally, songbirds within impounded and partially drawn-down wetland units with water flow had mercury concentrations that were 26-28% lower, respectively, than individuals within isolated-depressional wetlands with no outflow. Our results confirm that mercury concentrations in songbirds at Kellys Slough continue to be elevated and suggest that water-management could be an important tool for wetland managers to reduce bioaccumulation of mercury in birds.
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Affiliation(s)
- Virginia L Winder
- Department of Biology, Benedictine College, Atchison, KS, 66002, USA.
| | - Michael J Anteau
- Northern Prairie Wildlife Research Center, U.S. Geological Survey, 8711 37th St SE, Jamestown, ND, 58401, USA
| | - Mark R Fisher
- Devils Lake Wetland Management District, U.S. Fish and Wildlife Service, Devils Lake, ND, 58301, USA
| | - Mary Kate Wilcox
- Division of Biology, Kansas State University, Manhattan, KS, 66502, USA
| | - Lawrence D Igl
- Northern Prairie Wildlife Research Center, U.S. Geological Survey, 8711 37th St SE, Jamestown, ND, 58401, USA
| | - Joshua T Ackerman
- Western Ecological Research Center, Dixon Field Station, U.S. Geological Survey, 800 Business Park Drive, Suite D, Dixon, CA, 95620, USA
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21
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Baldwin AK, Poulin BA, Naymik J, Hoovestol C, Clark GM, Krabbenhoft DP. Seasonal Dynamics and Interannual Variability in Mercury Concentrations and Loads through a Three-Reservoir Complex. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:9305-9314. [PMID: 32667810 DOI: 10.1021/acs.est.9b07103] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The Hells Canyon Complex (HCC) along the Snake River (Idaho-Oregon border, U.S.A.) encompasses three successive reservoirs that seasonally stratify, creating anoxic conditions in the hypolimnion that promote methylmercury (MeHg) production. This study quantified seasonal dynamics and interannual variability in mercury concentrations (inorganic divalent mercury (IHg) and MeHg) and loads at four reservoir inflow and outflow locations through the HCC (2014-2017). We observed (1) that the HCC is a net sink for both IHg and MeHg, (2) interannual variability in IHg and MeHg loads largely reflecting streamflow conditions, and (3) seasonal variability in particulate IHg loading at the inflow (greatest from February to April) and MeHg export from the outflow (greatest from September to December) of the HCC. Seasonal export of MeHg was evidenced by increases in monthly mean concentrations of unfiltered MeHg (approximately 2-fold) and the percentage of total mercury (THg) as MeHg (≥4-fold) coincident with reservoir destratification. Despite evidence of seasonal export of MeHg from the HCC, annual loads indicate a 42% decrease in unfiltered MeHg from HCC inflow to outflow. Results from this study improve the understanding of seasonal variability in mercury transport through and transformation within a reservoir complex.
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Affiliation(s)
- Austin K Baldwin
- U.S. Geological Survey, 230 Collins Road, Boise, Idaho 83702, United States
| | - Brett A Poulin
- U.S. Geological Survey, 3215 Marine Street, Suite E127, Boulder, Colorado 80303, United States
- Department of Environmental Toxicology, University of California Davis, 1 Shields Avenue, Davis, CA 95616, United States
| | - Jesse Naymik
- Idaho Power Company, 1221 West Idaho Street, Boise, Idaho 83702, United States
| | - Charles Hoovestol
- Idaho Power Company, 1221 West Idaho Street, Boise, Idaho 83702, United States
| | - Gregory M Clark
- U.S. Geological Survey, 230 Collins Road, Boise, Idaho 83702, United States
| | - David P Krabbenhoft
- U.S. Geological Survey, 8505 Research Way, Middleton, Wisconsin 53562, United States
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22
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Eagles-Smith CA, Willacker JJ, Nelson SJ, Flanagan Pritz CM, Krabbenhoft DP, Chen CY, Ackerman JT, Grant EHC, Pilliod DS. A National-Scale Assessment of Mercury Bioaccumulation in United States National Parks Using Dragonfly Larvae As Biosentinels through a Citizen-Science Framework. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:8779-8790. [PMID: 32633494 PMCID: PMC7790342 DOI: 10.1021/acs.est.0c01255] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 06/03/2020] [Accepted: 06/04/2020] [Indexed: 06/01/2023]
Abstract
We conducted a national-scale assessment of mercury (Hg) bioaccumulation in aquatic ecosystems, using dragonfly larvae as biosentinels, by developing a citizen-science network to facilitate biological sampling. Implementing a carefully designed sampling methodology for citizen scientists, we developed an effective framework for a landscape-level inquiry that might otherwise be resource limited. We assessed the variation in dragonfly Hg concentrations across >450 sites spanning 100 United States National Park Service units and examined intrinsic and extrinsic factors associated with the variation in Hg concentrations. Mercury concentrations ranged between 10.4 and 1411 ng/g dry weight across sites and varied among habitat types. Dragonfly total Hg (THg) concentrations were up to 1.8-fold higher in lotic habitats than in lentic habitats and 37% higher in waterbodies with abundant wetlands along their margins than those without wetlands. Mercury concentrations in dragonflies differed among families but were correlated (r2 > 0.80) with each other, enabling adjustment to a consistent family to facilitate spatial comparisons among sampling units. Dragonfly THg concentrations were positively correlated with THg concentrations in both fish and amphibians from the same locations, indicating that dragonfly larvae are effective indicators of Hg bioavailability in aquatic food webs. We used these relationships to develop an integrated impairment index of Hg risk to aquatic ecosytems and found that 12% of site-years exceeded high or severe benchmarks of fish, wildlife, or human health risk. Collectively, this continental-scale study demonstrates the utility of dragonfly larvae for estimating the potential mercury risk to fish and wildlife in aquatic ecosystems and provides a framework for engaging citizen science as a component of landscape Hg monitoring programs.
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Affiliation(s)
- Collin A. Eagles-Smith
- United
States Geological Survey, Forest and Rangeland
Ecosystem Science Center, Corvallis, Oregon 97330, United States
| | - James J. Willacker
- United
States Geological Survey, Forest and Rangeland
Ecosystem Science Center, Corvallis, Oregon 97330, United States
| | - Sarah J. Nelson
- School
of Forest Resources, University of Maine, Orono, Maine 04469, United States
- Appalachian
Mountain Club, Gorham, New Hampshire 03581, United States
| | - Colleen M. Flanagan Pritz
- National
Park Service, Air Resources Division,
National Resource, Stewardship and Science Directorate, Lakewood, Colorado 80228, United States
| | - David P. Krabbenhoft
- United
States Geological Survey, Upper Midwest Water
Science Center, Middleton, Wisconsin 53562, United States
| | - Celia Y. Chen
- Department
of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Joshua T. Ackerman
- United
States Geological Survey, Western Ecological
Research Center, Dixon, California 95620, United States
| | - Evan H. Campbell Grant
- United
States Geological Survey, Patuxent Wildlife
Research Center, Turners Falls, Massachussetts 01376, United States
| | - David S. Pilliod
- United
States Geological Survey, Forest and Rangeland
Ecosystem Science Center, Boise, Idaho 83706, United States
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23
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Liu J, Wang D, Zhang J, Liem-Nguyen V, Huang R, Jiang T. Evaluation of Hg methylation in the water-level-fluctuation zone of the Three Gorges Reservoir region by using the MeHg/Hg T ratio. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 195:110468. [PMID: 32200146 DOI: 10.1016/j.ecoenv.2020.110468] [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: 12/16/2019] [Revised: 03/05/2020] [Accepted: 03/09/2020] [Indexed: 06/10/2023]
Abstract
In the recent decade, the hydroelectric reservoir is identified as a methylmercury (MeHg) hotspot and gained much attention. The artificial water level management in the Three Gorges Reservoir (TGR) in China formed a water-level-fluctuation zone (WLFZ) undergoing flooding drying rotations annually. However, the mercury (Hg) methylation and major geochemical driving factors at different elevations in the WLFZ remain unclear. Here we use total Hg (HgT) normalized MeHg (MeHg/HgT ratio) to evaluate Hg methylation degree in a one-year field study at 155, 165 m elevations in the WLFZ and with >175 m elevation as the reference. Results demonstrate that MeHg/HgT ratio at the WLFZ could reach 4.1% in soils, and both 155 and 165 m elevations have a higher Hg methylation degree than the >175 m elevation. However, the differences in MeHg/HgT ratios both in soils and waters between 155 and 165 m elevations are not significant. This indicates the influence of different submerging periods on the MeHg/HgT at the WLFZ elevations is not observed. The significant correlation between the MeHg/HgT ratio and soil organic carbon (SOC) content implies a MeHg retention in re-exposed soils after flooding. Decoupling of MeHg/HgT ratios between submerged soil and overlying water are found at both elevations and therefore make MeHg/HgT in waters alone cannot be used to evaluate Hg methylation degree in this study. The calculation of HgT and MeHg partitioning coefficient (Kd) found an immobilization of MeHg by submerged soils at the WLFZ during the flooding period. Major geochemical factors, determined through principal component analysis (PCA), in affecting Hg methylation are the redox cycling of sulfur and the distribution of organic matters in the WLFZ.
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Affiliation(s)
- Jiang Liu
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing, 400716, China; Centre for Earth Observation Science, Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
| | - Dingyong Wang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing, 400716, China.
| | - Jinzhong Zhang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing, 400716, China.
| | - Van Liem-Nguyen
- Laboratory of Advanced Materials Chemistry, Advanced Institute of Materials Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam; Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
| | - Rong Huang
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China.
| | - Tao Jiang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing, 400716, China.
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24
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Willacker JJ, Eagles-Smith CA, Blazer VS. Mercury bioaccumulation in freshwater fishes of the Chesapeake Bay watershed. ECOTOXICOLOGY (LONDON, ENGLAND) 2020; 29:459-484. [PMID: 32239332 DOI: 10.1007/s10646-020-02193-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/10/2020] [Indexed: 06/11/2023]
Abstract
Chemical contaminants are a threat to the Chesapeake Bay watershed, with mercury (Hg) among the most prevalent causes of impairment. Despite this, large-scale patterns of Hg concentrations, and the potential risks to fish, wildlife, and humans across the watershed, are poorly understood. We compiled fish Hg data from state monitoring programs and recent research efforts to address this knowledge gap and provide a comprehensive assessment of fish Hg concentrations in the watershed's freshwater habitats. The resulting dataset consisted of nearly 8000 total Hg (THg) concentrations from 600 locations. Across the watershed, fish THg concentrations spanned a 44-fold range, with mean concentrations varying by 2.6- and 8.8-fold among major sub-watersheds and individual 8-digit hydrological units, respectively. Although, mean THg concentrations tended to be moderate, fish frequently exceeded benchmarks for potential adverse health effects, with 45, 48, and 36% of all samples exceeding benchmarks for human, avian piscivore, and fish risk, respectively. Importantly, the percentage of fish exceeding these benchmarks was not uniform among species or locations. The variation in fish THg concentrations among species and sites highlights the roles of waterbody, landscape, and ecological processes in shaping broad patterns in Hg risk across the watershed. We outline an integrated Hg monitoring program that could identify key factors influencing Hg concentrations across the watershed and facilitate the implementation of management strategies to mitigate the risks posed by Hg.
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Affiliation(s)
- James J Willacker
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR, 97331, USA
| | - Collin A Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR, 97331, USA.
| | - Vicki S Blazer
- U.S. Geological Survey, Leetown Science Center, National Fish Health Research Laboratory, 11649 Leetown Road, Kearneysville, WV, 25430, USA
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25
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Eckley CS, Gilmour CC, Janssen S, Luxton TP, Randall PM, Whalin L, Austin C. The assessment and remediation of mercury contaminated sites: A review of current approaches. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 707:136031. [PMID: 31869604 PMCID: PMC6980986 DOI: 10.1016/j.scitotenv.2019.136031] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/07/2019] [Accepted: 12/07/2019] [Indexed: 04/13/2023]
Abstract
Remediation of mercury (Hg) contaminated sites has long relied on traditional approaches, such as removal and containment/capping. Here we review contemporary practices in the assessment and remediation of industrial-scale Hg contaminated sites and discuss recent advances. Significant improvements have been made in site assessment, including the use of XRF to rapidly identify the spatial extent of contamination, Hg stable isotope fractionation to identify sources and transformation processes, and solid-phase characterization (XAFS) to evaluate Hg forms. The understanding of Hg bioavailability for methylation has been improved by methods such as sequential chemical extractions and porewater measurements, including the use of diffuse gradient in thin-film (DGT) samplers. These approaches have shown varying success in identifying bioavailable Hg fractions and further study and field applications are needed. The downstream accumulation of methylmercury (MeHg) in biota is a concern at many contaminated sites. Identifying the variables limiting/controlling MeHg production-such as bioavailable inorganic Hg, organic carbon, and/or terminal electron acceptors (e.g. sulfate, iron) is critical. Mercury can be released from contaminated sites to the air and water, both of which are influenced by meteorological and hydrological conditions. Mercury mobilized from contaminated sites is predominantly bound to particles, highly correlated with total sediment solids (TSS), and elevated during stormflow. Remediation techniques to address Hg contamination can include the removal or containment of Hg contaminated materials, the application of amendments to reduce mobility and bioavailability, landscape/waterbody manipulations to reduce MeHg production, and food web manipulations through stocking or extirpation to reduce MeHg accumulated in desired species. These approaches often rely on knowledge of the Hg forms/speciation at the site, and utilize physical, chemical, thermal and biological methods to achieve remediation goals. Overall, the complexity of Hg cycling allows many different opportunities to reduce/mitigate impacts, which creates flexibility in determining suitable and logistically feasible remedies.
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Affiliation(s)
- Chris S Eckley
- U.S. Environmental Protection Agency, Region-10, 1200 6th Ave, Seattle, WA 98101, USA.
| | - Cynthia C Gilmour
- Smithsonian Environmental Research Center, 647 Contees Wharf Rd., Edgewater, MD 21037-0028, USA.
| | - Sarah Janssen
- USGS Upper Midwest Water Science Center, 8505 Research Way, Middleton, WI 53562, USA.
| | - Todd P Luxton
- US Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
| | - Paul M Randall
- US Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, USA.
| | - Lindsay Whalin
- San Francisco Bay Water Board, 1515 Clay St., Ste. 1400, Oakland, CA 94612, USA.
| | - Carrie Austin
- San Francisco Bay Water Board, 1515 Clay St., Ste. 1400, Oakland, CA 94612, USA.
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26
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Day NK, Schmidt TS, Roberts JJ, Osmundson BC, Willacker JJ, Eagles-Smith CA. Mercury and selenium concentrations in fishes of the Upper Colorado River Basin, southwestern United States: A retrospective assessment. PLoS One 2020; 15:e0226824. [PMID: 31929573 PMCID: PMC6957192 DOI: 10.1371/journal.pone.0226824] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 12/04/2019] [Indexed: 11/18/2022] Open
Abstract
Mercury (Hg) and selenium (Se) are contaminants of concern for fish in the Upper Colorado River Basin (UCRB). We explored Hg and Se in fish tissues (2,324 individuals) collected over 50 years (1962-2011) from the UCRB. Samples include native and non-native fish collected from lotic waterbodies spanning 7 major tributaries to the Colorado River. There was little variation of total mercury (THg) in fish assemblages basin-wide and only 13% (272/1959) of individual fish samples exceeded the fish health benchmark (0.27 μg THg/g ww). Most THg exceedances were observed in the White-Yampa tributary whereas the San Juan had the lowest mean THg concentration. Risks associated with THg are species specific with exceedances dominated by Colorado Pikeminnow (mean = 0.38 and standard error ± 0.08 μg THg/g ww) and Roundtail Chub (0.24 ± 0.06 μg THg/g ww). For Se, 48% (827/1720) of all individuals exceeded the fish health benchmark (5.1 μg Se/g dw). The Gunnison river had the most individual exceedances of the Se benchmark (74%) whereas the Dirty Devil had the fewest. We identified that species of management concern accumulate THg and Se to levels above risk thresholds and that fishes of the White-Yampa (THg) and Gunnison (Se) rivers are at the greatest risk in the UCRB.
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Affiliation(s)
- Natalie K. Day
- U.S. Geological Survey, Southwest Biological Science Center, Moab, Utah, United States of America
| | - Travis S. Schmidt
- U.S. Geological Survey, Colorado Water Science Center, Fort Collins, Colorado, United States of America
| | - James J. Roberts
- U.S. Geological Survey, Colorado Water Science Center, Fort Collins, Colorado, United States of America
| | - Barbara C. Osmundson
- U.S. Fish and Wildlife Service, Grand Junction, Colorado, United States of America
| | - James J. Willacker
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, Oregon, United States of America
| | - Collin A. Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, Oregon, United States of America
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Ackerman JT, Fleck JA, Eagles-Smith CA, Marvin-DiPasquale M, Windham-Myers L, Herzog MP, McQuillen HL. Wetland Management Strategy to Reduce Mercury in Water and Bioaccumulation in Fish. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2019; 38:2178-2196. [PMID: 31343757 DOI: 10.1002/etc.4535] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/08/2019] [Accepted: 07/09/2019] [Indexed: 06/10/2023]
Abstract
Wetland environments provide numerous ecosystem services but also facilitate methylmercury (MeHg) production and bioaccumulation. We developed a wetland-management technique to reduce MeHg concentrations in wetland fish and water. We physically modified seasonal wetlands by constructing open- and deep-water treatment cells at the downstream end of seasonal wetlands to promote naturally occurring MeHg-removal processes. We assessed the effectiveness of reducing mercury (Hg) concentrations in surface water and western mosquitofish that were caged at specific locations within 4 control and 4 treatment wetlands. Methylmercury concentrations in wetland water were successfully decreased within treatment cells during only the third year of study; however, treatment cells were not effective for reducing total Hg concentrations. Furthermore, treatment cells were not effective for reducing total Hg concentrations in wetland fish. Mercury concentrations in fish were not correlated with total Hg concentrations in filtered, particulate, or whole water; and the slope of the correlation with water MeHg concentrations differed between months. Fish total Hg concentrations were weakly correlated with water MeHg concentrations in April when fish were introduced into cages but were not correlated in May when fish were retrieved from cages. Fish total Hg concentrations were greater in treatment wetlands than in control wetlands the year after the treatment wetlands' construction but declined by the second year. During the third year, fish total Hg concentrations increased in both control and treatment wetlands after an unexpected regional flooding event. Overall, we found limited support for the use of open- and deep-water treatment cells at the downstream end of wetlands to reduce MeHg concentrations in water but not fish. We suggest that additional evaluation over a longer period of time is necessary. Environ Toxicol Chem 2019;38:2178-2196. Published 2019 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work, and as such, is in the public domain in the United States of America..
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Affiliation(s)
- Joshua T Ackerman
- US Geological Survey, Western Ecological Research Center, Dixon Field Station, Dixon, California
| | - Jacob A Fleck
- US Geological Survey, California Water Science Center, Sacramento, California
| | - Collin A Eagles-Smith
- US Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, Oregon
| | | | | | - Mark P Herzog
- US Geological Survey, Western Ecological Research Center, Dixon Field Station, Dixon, California
| | - Harry L McQuillen
- US Bureau of Land Management, Cosumnes River Preserve, Galt, California
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28
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Wang F, Outridge PM, Feng X, Meng B, Heimbürger-Boavida LE, Mason RP. How closely do mercury trends in fish and other aquatic wildlife track those in the atmosphere? - Implications for evaluating the effectiveness of the Minamata Convention. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 674:58-70. [PMID: 31003088 DOI: 10.1016/j.scitotenv.2019.04.101] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 04/07/2019] [Accepted: 04/08/2019] [Indexed: 05/28/2023]
Abstract
The Minamata Convention to reduce anthropogenic mercury (Hg) emissions entered into force in 2017, and attention is now focused on how to best monitor its effectiveness at reducing Hg exposure to humans. A key question is how closely Hg concentrations in the human food chain, especially in fish and other aquatic wildlife, will track the changes in atmospheric Hg that are expected to occur following anthropogenic emission reductions. We investigated this question by evaluating several regional groups of case studies where Hg concentrations in aquatic biota have been monitored continuously or intermittently for several decades. Our analysis shows that in most cases Hg time trends in biota did not agree with concurrent Hg trends in atmospheric deposition or concentrations, and the divergence between the two trends has become more apparent over the past two decades. An over-arching general explanation for these results is that the impact of changing atmospheric inputs on biotic Hg is masked by two factors: 1) The aquatic environment contains a large inventory of legacy emitted Hg that remains available for bio-uptake leading to a substantial lag in biotic response time to a change in external inputs; and 2) Biotic Hg trends reflect the dominant effects of changes in multi-causal, local and regional processes (e.g., aquatic or terrestrial biogeochemical processes, feeding ecology, climate) that control the speciation, bioavailability, and bio-uptake of both present-day and legacy emitted Hg. Globally, climate change has become the most prevalent contributor to the divergence. A wide range of biotic Hg outcomes can thus be expected as anthropogenic atmospheric Hg emissions decline, depending on how these processes operate on specific regions and specific organisms. Therefore, evaluating the effectiveness of the Minamata Convention will require biomonitoring of multiple species that represent different trophic and ecological niches in multiple regions of the world.
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Affiliation(s)
- Feiyue Wang
- Centre for Earth Observation Science, and Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
| | - Peter M Outridge
- Centre for Earth Observation Science, and Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; Geological Survey of Canada, Natural Resources Canada, 601 Booth St., Ottawa, ON K1A 0E8, Canada
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46 Guanshui Road, Guiyang 550002, China
| | - Bo Meng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46 Guanshui Road, Guiyang 550002, China
| | - Lars-Eric Heimbürger-Boavida
- Aix Marseille Université, CNRS/INSU, Université de Toulon, IRD, Mediterranean Institute of Oceanography (MIO) UM 110, 13288 Marseille, France
| | - Robert P Mason
- Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Road, Groton, CT 06340, USA
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Crowley SM, Hodder DP. Factors influencing exposure of North American river otter (Lontra canadensis) and American mink (Neovison vison) to mercury relative to a large-scale reservoir in northern British Columbia, Canada. ECOTOXICOLOGY (LONDON, ENGLAND) 2019; 28:343-353. [PMID: 30826954 DOI: 10.1007/s10646-019-02027-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/08/2019] [Indexed: 06/09/2023]
Abstract
Although reservoir creation increases fish mercury (Hg) concentrations, little information exists on its effects on Hg concentrations in aquatic mammals. River otters (Lontra canadensis) and American mink (Neovison vison) are two aquatic mammals that have been used as model species for assessing Hg bioaccumulation in aquatic systems. We assessed Hg and selenium (Se) concentrations in these two species within and outside of the Williston Reservoir (Peace-Williston (PW) watershed) in northern British Columbia (BC) and used these data to investigate potential explanatory factors (i.e., watershed, gender, trophic level (δ15N), and regional geology) influencing Hg concentrations. Hg concentrations in otter and mink inhabiting the Mackenzie watershed (outside the PW) were significantly lower than other watersheds in Northern BC. The general trend was the same for both species; the Peace-Williston having the highest and Mackenzie having the lowest Hg concentrations. For mink, the Peace-Williston watershed, higher trophic levels, and higher proportions of igneous/metamorphic bedrock were all significant influences on higher Hg concentrations (logistic regression). Higher trophic levels or proportions of of igneous/metamorphic bedrock, however, were not directly associated with the PW watershed suggesting there may be an impoundment effect. Baseline data on natural Hg inputs before planned anthropogenic changes occur is a critical first step to aiding interpretations of Hg-related effects on wildlife populations and their related ecosystems.
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Affiliation(s)
- Shannon M Crowley
- John Prince Research Forest, Fort St. James, P.O. Box 2378, BC V0J 1P0, Canada.
| | - Dexter P Hodder
- John Prince Research Forest, Fort St. James, P.O. Box 2378, BC V0J 1P0, Canada
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Kolka RK, Riggs CE, Nater EA, Wickman TR, Witt EL, Butcher JT. Temporal fluctuations in young-of-the-year yellow perch mercury bioaccumulation in lakes of northeastern Minnesota. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 656:475-481. [PMID: 30522030 DOI: 10.1016/j.scitotenv.2018.11.280] [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: 08/27/2017] [Revised: 11/14/2018] [Accepted: 11/18/2018] [Indexed: 06/09/2023]
Abstract
Identifying what determines fish mercury (Hg) bioaccumulation remains a key scientific challenge. While there has been substantial research on spatial variation in fish Hg bioaccumulation, the factors that influence temporal fluctuations in fish Hg have received less attention to date. In this study, we built upon a growing body of research investigating young-of-the-year (YOY) yellow perch Hg bioaccumulation and investigated annual fluctuations in YOY yellow perch Hg in six lakes in northeastern Minnesota over eight years. After accounting for spatial variation between the study lakes, we used model averaging to identify the lake physiochemical and climate factors that best explain temporal variation in fish biomass and fish Hg. Fish biomass of YOY yellow perch had a positive relationship with chlorophyll-α and total Kjeldahl nitrogen and a negative relationship with dissolved iron and dissolved oxygen. There was a positive relationship between annual variation in yellow perch Hg concentration and annual variation in lake total suspended solids, dissolved Fe and pH. Additionally, there was a negative relationship between fish Hg concentration and lake total Kjeldahl nitrogen and growing degree days. Together, our results suggest that annual variation in allochthonous inputs from the watershed, in-lake processes, and climate variables can explain temporal patterns in Hg bioaccumulation and growth biodilution is an important process controlling yellow perch Hg concentrations.
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Affiliation(s)
- Randall K Kolka
- USDA Forest Service, Northern Research Station, 1831 Highway 169 East, Grand Rapids, MN 55744, USA.
| | - Charlotte E Riggs
- University of Minnesota, Department of Soil, Water, and Climate, 1991 Upper Buford Circle, Saint Paul, MN 55108, USA.
| | - Edward A Nater
- University of Minnesota, Department of Soil, Water, and Climate, 1991 Upper Buford Circle, Saint Paul, MN 55108, USA.
| | - Trent R Wickman
- USDA Forest Service, Eastern Region, 8901 Grand Ave Place, Duluth, MN 55808, USA.
| | - Emma L Witt
- Stockton University, School of Natural Sciences and Mathematics, 101 Vera King Farris Drive, Galloway, NJ 08205, USA.
| | - Jason T Butcher
- USDA Forest Service, Superior National Forest, 8901 Grand Ave Place, Duluth, MN 55808, USA.
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Johnson TKB, LePrevost CE, Kwak TJ, Cope WG. Selenium, Mercury, and Their Molar Ratio in Sportfish from Drinking Water Reservoirs. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15091864. [PMID: 30158428 PMCID: PMC6164800 DOI: 10.3390/ijerph15091864] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 08/17/2018] [Accepted: 08/21/2018] [Indexed: 01/26/2023]
Abstract
Mercury (Hg) bioaccumulates in aquatic ecosystems and may pose a risk to humans who consume fish. Selenium (Se) has the ability to reduce Hg toxicity, but the current guidance for human consumption of fish is based on Hg concentration alone. The purpose of the present study was to examine the relationship between Se and Hg in freshwater sportfish, for which there is a paucity of existing data. We collected three species of fish from different trophic positions from two drinking water reservoirs in central North Carolina, USA, to assess Hg and Se concentrations in relation to fish total length and to compare two measures of the protective ability of Se, the Se:Hg molar ratio and Se health benefit value (HBVSe), to current guidance for Hg. According to the Se:Hg molar ratio, all of the low trophic position fish sampled and the middle trophic position fish sampled from one of the reservoirs were safe for consumption. The same number of fish were considered safe using the HBVSe. More fish were deemed unsafe when using the Se:Hg molar ratio and HBVSe than were considered unsafe when using the U.S. Environmental Protection Agency (USEPA) Hg threshold. These findings suggest that the measures of Se protection may be unnecessarily conservative or that the USEPA Hg threshold may not be sufficiently protective of human health, especially the health of sensitive populations like pregnant or nursing mothers and young children. Future examination of the Se:Hg molar ratio and HBVSe from a variety of fish tissue samples would help refine the accuracy of these measures so that they may be appropriately utilized in ecological and human health risk assessment.
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Affiliation(s)
- Tara K B Johnson
- Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695, USA.
| | - Catherine E LePrevost
- Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695, USA.
| | - Thomas J Kwak
- U.S. Geological Survey, North Carolina Cooperative Fish and Wildlife Research Unit, Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695, USA.
| | - W Gregory Cope
- Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695, USA.
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Liu J, Jiang T, Wang F, Zhang J, Wang D, Huang R, Yin D, Liu Z, Wang J. Inorganic sulfur and mercury speciation in the water level fluctuation zone of the Three Gorges Reservoir, China: The role of inorganic reduced sulfur on mercury methylation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 237:1112-1123. [PMID: 29153472 DOI: 10.1016/j.envpol.2017.11.045] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 10/06/2017] [Accepted: 11/11/2017] [Indexed: 06/07/2023]
Abstract
The water level fluctuation zone (WLFZ) of the Three Gorges Reservoir (TGR) in China is a unique geomorphological unit that undergoes annual flooding and drying alternation cycle. The alternating redox conditions within the WLFZ are expected to result in dynamic cycling of reduced sulfur species, which could affect mercury (Hg) methylation due to the high affinity of reduced sulfur species to both inorganic divalent mercury (Hg(II)i) and methylmercury (MeHg). Variations of inorganic sulfur species (measured as acid volatile sulfide, chromium reductive sulfur, elemental sulfur, and water-soluble sulfate), total mercury (THg) and MeHg were studied at two typical WLFZ sites in the TGR from July 2015 to June 2016. Whereas the water-soluble sulfate contents stayed essentially constant, the reduced inorganic sulfur contents varied greatly as the water level changed. Compared with the control soils, the MeHg contents in the WLFZ soils increased, suggesting that water level fluctuations accelerated the methylation process of Hg(II)i. In situ Hg(II)i-methylation also appeared to occur in the sub-layer of the drained sediment during the draw-down season. The significant correlation between MeHg and elemental sulfur (S(0)) further suggests that polysulfides may have played a role in Hg(II)i-methylation by increasing the bioavailable Hg(II)i content in the WLFZ of the TGR.
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Affiliation(s)
- Jiang Liu
- College of Resources and Environment, Southwest University, Key Laboratory of Eco-environments in the Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, PR China; Centre for Earth Observation Science, Department of Environment and Geography, University of Manitoba, Winnipeg MB R3T 2N2, Canada
| | - Tao Jiang
- College of Resources and Environment, Southwest University, Key Laboratory of Eco-environments in the Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, PR China; Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå SE-90183, Sweden
| | - Feiyue Wang
- Centre for Earth Observation Science, Department of Environment and Geography, University of Manitoba, Winnipeg MB R3T 2N2, Canada.
| | - Jinzhong Zhang
- College of Resources and Environment, Southwest University, Key Laboratory of Eco-environments in the Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, PR China.
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Key Laboratory of Eco-environments in the Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, PR China
| | - Rong Huang
- College of Resources and Environment, Southwest University, Key Laboratory of Eco-environments in the Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, PR China
| | - Deliang Yin
- College of Resources and Environment, Southwest University, Key Laboratory of Eco-environments in the Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, PR China
| | - Zeyan Liu
- College of Resources and Environment, Southwest University, Key Laboratory of Eco-environments in the Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, PR China
| | - Jinzhu Wang
- College of Resources and Environment, Southwest University, Key Laboratory of Eco-environments in the Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, PR China
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Eagles-Smith CA, Silbergeld EK, Basu N, Bustamante P, Diaz-Barriga F, Hopkins WA, Kidd KA, Nyland JF. Modulators of mercury risk to wildlife and humans in the context of rapid global change. AMBIO 2018; 47:170-197. [PMID: 29388128 PMCID: PMC5794686 DOI: 10.1007/s13280-017-1011-x] [Citation(s) in RCA: 193] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Environmental mercury (Hg) contamination is an urgent global health threat. The complexity of Hg in the environment can hinder accurate determination of ecological and human health risks, particularly within the context of the rapid global changes that are altering many ecological processes, socioeconomic patterns, and other factors like infectious disease incidence, which can affect Hg exposures and health outcomes. However, the success of global Hg-reduction efforts depends on accurate assessments of their effectiveness in reducing health risks. In this paper, we examine the role that key extrinsic and intrinsic drivers play on several aspects of Hg risk to humans and organisms in the environment. We do so within three key domains of ecological and human health risk. First, we examine how extrinsic global change drivers influence pathways of Hg bioaccumulation and biomagnification through food webs. Next, we describe how extrinsic socioeconomic drivers at a global scale, and intrinsic individual-level drivers, influence human Hg exposure. Finally, we address how the adverse health effects of Hg in humans and wildlife are modulated by a range of extrinsic and intrinsic drivers within the context of rapid global change. Incorporating components of these three domains into research and monitoring will facilitate a more holistic understanding of how ecological and societal drivers interact to influence Hg health risks.
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Affiliation(s)
| | - Ellen K. Silbergeld
- Johns Hopkin Bloomberg School of Public Health, 615 N. Wolfe Street, E6644, Baltimore, MD 21205 USA
| | - Niladri Basu
- McGill University, 204-CINE Building, Montreal, QC H9X 3V9 Canada
| | - Paco Bustamante
- University of La Rochelle, laboratory of Littoral Environment and Societies, Littoral Environnement et Sociétés (LIENSs), LIENSs UMR 7266 CNRS-Université de La Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle, France
| | - Fernando Diaz-Barriga
- Center for Applied Research in Environment and Health at, Universidad Autonoma de San Luis Potosi, Avenida Venustiano Carranza No. 2405, Col Lomas los Filtros Código Postal, 78214 San Luis Potosí, SLP Mexico
| | - William A. Hopkins
- Department of Fish and Wildlife Conservation, 310 West Campus Drive Virginia Tech, Cheatham Hall, Room 106 (MC 0321), Blacksburg, VA 24061 USA
| | - Karen A. Kidd
- Department of Biology & School of Geography and Earth Sciences, McMaster University, 1280 Main Street W., Hamilton, ON L8S 4K1 Canada
| | - Jennifer F. Nyland
- Department of Biological Sciences, 1101 Camden Ave, Salisbury, MD 21801 USA
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Hsu-Kim H, Eckley CS, Achá D, Feng X, Gilmour CC, Jonsson S, Mitchell CPJ. Challenges and opportunities for managing aquatic mercury pollution in altered landscapes. AMBIO 2018; 47:141-169. [PMID: 29388127 PMCID: PMC5794684 DOI: 10.1007/s13280-017-1006-7] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The environmental cycling of mercury (Hg) can be affected by natural and anthropogenic perturbations. Of particular concern is how these disruptions increase mobilization of Hg from sites and alter the formation of monomethylmercury (MeHg), a bioaccumulative form of Hg for humans and wildlife. The scientific community has made significant advances in recent years in understanding the processes contributing to the risk of MeHg in the environment. The objective of this paper is to synthesize the scientific understanding of how Hg cycling in the aquatic environment is influenced by landscape perturbations at the local scale, perturbations that include watershed loadings, deforestation, reservoir and wetland creation, rice production, urbanization, mining and industrial point source pollution, and remediation. We focus on the major challenges associated with each type of alteration, as well as management opportunities that could lessen both MeHg levels in biota and exposure to humans. For example, our understanding of approximate response times to changes in Hg inputs from various sources or landscape alterations could lead to policies that prioritize the avoidance of certain activities in the most vulnerable systems and sequestration of Hg in deep soil and sediment pools. The remediation of Hg pollution from historical mining and other industries is shifting towards in situ technologies that could be less disruptive and less costly than conventional approaches. Contemporary artisanal gold mining has well-documented impacts with respect to Hg; however, significant social and political challenges remain in implementing effective policies to minimize Hg use. Much remains to be learned as we strive towards the meaningful application of our understanding for stakeholders, including communities living near Hg-polluted sites, environmental policy makers, and scientists and engineers tasked with developing watershed management solutions. Site-specific assessments of MeHg exposure risk will require new methods to predict the impacts of anthropogenic perturbations and an understanding of the complexity of Hg cycling at the local scale.
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Affiliation(s)
- Heileen Hsu-Kim
- Department of Civil & Environmental Engineering, Duke University, 121 Hudson Hall, Box 90287, Durham, NC 27708 USA
| | - Chris S. Eckley
- U.S. Environmental Protection Agency, Region-10, 1200 6th Ave, Seattle, WA 98101 USA
| | - Dario Achá
- Unidad de Calidad Ambiental, Instituto de Ecología, Carrera de Biología, Universidad Mayor de San Andrés, P.O. Box 10077, La Paz, Bolivia
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002 China
| | - Cynthia C. Gilmour
- Smithsonian Environmental Research Center, 647 Contees Wharf Rd, Edgewater, MD 21037-0028 USA
| | - Sofi Jonsson
- Department of Environmental Science and Analytical Chemistry, Stockholm University, Svante Arrhenius väg 8, 11418 Stockholm, Sweden
| | - Carl P. J. Mitchell
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4 Canada
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Silverthorn VM, Bishop CA, Jardine T, Elliott JE, Morrissey CA. Impact of flow diversion by run-of-river dams on American dipper diet and mercury exposure. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2018; 37:411-426. [PMID: 29092091 DOI: 10.1002/etc.3961] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 05/13/2017] [Accepted: 08/22/2017] [Indexed: 06/07/2023]
Abstract
Run-of-river dams produce lower greenhouse gas emissions than large hydropower projects, but there is a paucity of research on their potential ecotoxicological impacts through disruption of natural flow regimes. We used stable isotopes (δ13 C, δ15 N, δ34 S) to reconstruct diet and trace methylmercury in a predatory river-resident passerine, the American dipper (Cinclus mexicanus), at 7 regulated and 6 free-flowing mountain streams in coastal British Columbia, Canada. Assimilated diets were comparable among regulated and unregulated streams, dominated by benthic macroinvertebrates and resident freshwater fish, with negligible contributions from anadromous Pacific salmon. Although invertebrates at unregulated streams were isotopically similar along their gradient, dippers and invertebrates sampled below dams on regulated streams had 34 S-depleted tissues, suggesting increased activity of sulfate-reducing bacteria and more Hg methylation below the dams. Mercury concentrations in dipper blood (417.6 ± 74.1 standard error [SE] ng/g wet wt at regulated streams, 340.7 ± 42.7 SE ng/g wet wt at unregulated streams) and feathers (1564 .6 ± 367.2 SE ng/g dry wt regulated, 1149.0 ± 152.1 SE ng/g dry wt unregulated), however, were not significantly different between stream types. Relative to other passerines across western North America, dippers in these densely forested mountain streams experienced high mercury exposure; and one recently regulated stream supported dippers with mercury concentrations of potential toxicity concern (up to 8459.5 ng/g dry wt in feathers and 1824.6 ng/g wet wt in whole blood). Elevated mercury in dippers is likely attributable to the birds' relatively high trophic position and high regional inorganic mercury deposition; however, biogeochemical conditions in reservoirs of some regulated streams may be contributing to methylmercury production. Environ Toxicol Chem 2018;37:411-426. © 2017 SETAC.
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Affiliation(s)
| | - Christine A Bishop
- Environment and Climate Change Canada, Wildlife and Landscape Science Division, Delta, British Columbia, Canada
| | - Timothy Jardine
- School of Environment and Sustainability, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - John E Elliott
- Environment and Climate Change Canada, Wildlife and Landscape Science Division, Delta, British Columbia, Canada
| | - Christy A Morrissey
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- School of Environment and Sustainability, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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Klapstein SJ, O'Driscoll NJ. Methylmercury Biogeochemistry in Freshwater Ecosystems: A Review Focusing on DOM and Photodemethylation. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2018; 100:14-25. [PMID: 29248954 DOI: 10.1007/s00128-017-2236-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 12/02/2017] [Indexed: 05/16/2023]
Abstract
Mercury contamination is a growing concern for freshwater food webs in ecosystems without point sources of mercury. Methylmercury (MeHg) is of particular concern, as this is the form of mercury that crosses the blood-brain barrier and is neurotoxic to organisms. Wetlands and benthic sediments have high organic content and low oxygen availability. Anaerobic bacteria drive the metabolic function in these ecosystems and subsequently can methylate mercury. The bioavailability of MeHg is controlled by physicochemical characteristics such as pH, binding affinities, and dissolved organic matter (DOM). Similarly, photodemethylation is influenced by similar characteristics and thereby the two processes should be studied in tandem. The degradation of MeHg through photochemistry is an effective destruction mechanism in freshwater lakes. This review will highlight the uncertainties and known effects of DOM on subsequent photoreactions that lead to the occurrence of mercury photodemethylation and reduction in mercury bioavailability in freshwater ecosystems.
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Affiliation(s)
- Sara J Klapstein
- Environmental Sciences Program, Memorial University of Newfoundland, St. John's, NL, Canada.
- Earth and Environmental Science Department, Acadia University, Wolfville, NS, Canada.
| | - Nelson J O'Driscoll
- Earth and Environmental Science Department, Acadia University, Wolfville, NS, Canada
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37
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Forsberg BR, Melack JM, Dunne T, Barthem RB, Goulding M, Paiva RCD, Sorribas MV, Silva UL, Weisser S. The potential impact of new Andean dams on Amazon fluvial ecosystems. PLoS One 2017; 12:e0182254. [PMID: 28832638 PMCID: PMC5568116 DOI: 10.1371/journal.pone.0182254] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 07/14/2017] [Indexed: 11/24/2022] Open
Abstract
Increased energy demand has led to plans for building many new dams in the western Amazon, mostly in the Andean region. Historical data and mechanistic scenarios are used to examine potential impacts above and below six of the largest dams planned for the region, including reductions in downstream sediment and nutrient supplies, changes in downstream flood pulse, changes in upstream and downstream fish yields, reservoir siltation, greenhouse gas emissions and mercury contamination. Together, these six dams are predicted to reduce the supply of sediments, phosphorus and nitrogen from the Andean region by 69, 67 and 57% and to the entire Amazon basin by 64, 51 and 23%, respectively. These large reductions in sediment and nutrient supplies will have major impacts on channel geomorphology, floodplain fertility and aquatic productivity. These effects will be greatest near the dams and extend to the lowland floodplains. Attenuation of the downstream flood pulse is expected to alter the survival, phenology and growth of floodplain vegetation and reduce fish yields below the dams. Reservoir filling times due to siltation are predicted to vary from 106-6240 years, affecting the storage performance of some dams. Total CO2 equivalent carbon emission from 4 Andean dams was expected to average 10 Tg y-1 during the first 30 years of operation, resulting in a MegaWatt weighted Carbon Emission Factor of 0.139 tons C MWhr-1. Mercury contamination in fish and local human populations is expected to increase both above and below the dams creating significant health risks. Reservoir fish yields will compensate some downstream losses, but increased mercury contamination could offset these benefits.
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Affiliation(s)
- Bruce R. Forsberg
- Environmental Dynamics Department, National Institute for Amazon Research, Manaus, Amazonas, Brazil
| | - John M. Melack
- Bren School of Environmental Science and Management, University of California, Santa Barbara, California, United States of America
| | - Thomas Dunne
- Bren School of Environmental Science and Management, University of California, Santa Barbara, California, United States of America
| | | | - Michael Goulding
- Wildlife Conservation Society, New York, New York, United States of America
| | - Rodrigo C. D. Paiva
- Institute of Hydraulic Research, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Mino V. Sorribas
- Institute of Hydraulic Research, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Urbano L. Silva
- National Center for Research and Conservation of Amazon Biodiversity, Chico Mendes Institute for Biodiversity Conservation, Manaus, Amazonas, Brazil
| | - Sabine Weisser
- Department of Biology, University of Konstanz, Konstanz, Germany
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38
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Riggs CE, Kolka RK, Nater EA, Witt EL, Wickman TR, Woodruff LG, Butcher JT. Yellow Perch ( Perca flavescens) Mercury Unaffected by Wildland Fires in Northern Minnesota. JOURNAL OF ENVIRONMENTAL QUALITY 2017; 46:623-631. [PMID: 28724108 DOI: 10.2134/jeq2016.10.0418] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Wildland fire can alter mercury (Hg) cycling on land and in adjacent aquatic environments. In addition to enhancing local atmospheric Hg redeposition, fire can influence terrestrial movement of Hg and other elements into lakes via runoff from burned upland soil. However, the impact of fire on water quality and the accumulation of Hg in fish remain equivocal. We investigated the effects of fire-specifically, a low-severity prescribed fire and moderate-severity wildfire-on young-of-the-year yellow perch () and lake chemistry in a small remote watershed in the Boundary Waters Canoe Area Wilderness in northeastern Minnesota. We used a paired watershed approach: the fire-affected watershed was compared with an adjacent, unimpacted (reference) watershed. Prior to fire, upland organic horizons in the two study watersheds contained 1549 μg Hg m on average. Despite a 19% decrease in upland organic horizon Hg stocks due to the moderate severity wildfire fire, fish Hg accumulation and lake productivity were not affected by fire in subsequent years. Instead, climate and lake water levels were the strongest predictors of lake chemistry and fish responses in our study lakes over 9 yr. Our results suggest that low- to moderate-severity wildland fire does not alter lake productivity or Hg accumulation in young-of-the-year yellow perch in these small, shallow lakes in the northern deciduous and boreal forest region.
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39
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Eckley CS, Luxton TP, Goetz J, McKernan J. Water-level fluctuations influence sediment porewater chemistry and methylmercury production in a flood-control reservoir. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 222:32-41. [PMID: 28104341 PMCID: PMC6498431 DOI: 10.1016/j.envpol.2017.01.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 12/15/2016] [Accepted: 01/07/2017] [Indexed: 05/26/2023]
Abstract
Reservoirs typically have elevated fish mercury (Hg) levels compared to natural lakes and rivers. A unique feature of reservoirs is water-level management which can result in sediment exposure to the air. The objective of this study is to identify how reservoir water-level fluctuations impact Hg cycling, particularly the formation of the more toxic and bioaccumulative methylmercury (MeHg). Total-Hg (THg), MeHg, stable isotope methylation rates and several ancillary parameters were measured in reservoir sediments (including some in porewater and overlying water) that are seasonally and permanently inundated. The results showed that sediment and porewater MeHg concentrations were over 3-times higher in areas experiencing water-level fluctuations compared to permanently inundated sediments. Analysis of the data suggest that the enhanced breakdown of organic matter in sediments experiencing water-level fluctuations has a two-fold effect on stimulating Hg methylation: 1) it increases the partitioning of inorganic Hg from the solid phase into the porewater phase (lower log Kd values) where it is more bioavailable for methylation; and 2) it increases dissolved organic carbon (DOC) in the porewater which can stimulate the microbial community that can methylate Hg. Sulfate concentrations and cycling were enhanced in the seasonally inundated sediments and may have also contributed to increased MeHg production. Overall, our results suggest that reservoir management actions can have an impact on the sediment-porewater characteristics that affect MeHg production. Such findings are also relevant to natural water systems that experience wetting and drying cycles, such as floodplains and ombrotrophic wetlands.
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Affiliation(s)
- Chris S Eckley
- US Environmental Protection Agency, Region-10. 1200, 6th Ave Seattle, WA 98101, USA
| | - Todd P Luxton
- US Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
| | - Jennifer Goetz
- US Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA
| | - John McKernan
- US Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA
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Eagles-Smith CA, Ackerman JT, Willacker JJ, Tate MT, Lutz MA, Fleck JA, Stewart AR, Wiener JG, Evers DC, Lepak JM, Davis JA, Pritz CF. Spatial and temporal patterns of mercury concentrations in freshwater fish across the Western United States and Canada. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 568:1171-1184. [PMID: 27102274 DOI: 10.1016/j.scitotenv.2016.03.229] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 03/17/2016] [Accepted: 03/17/2016] [Indexed: 05/25/2023]
Abstract
Methylmercury contamination of fish is a global threat to environmental health. Mercury (Hg) monitoring programs are valuable for generating data that can be compiled for spatially broad syntheses to identify emergent ecosystem properties that influence fish Hg bioaccumulation. Fish total Hg (THg) concentrations were evaluated across the Western United States (US) and Canada, a region defined by extreme gradients in habitat structure and water management. A database was compiled with THg concentrations in 96,310 fish that comprised 206 species from 4262 locations, and used to evaluate the spatial distribution of fish THg across the region and effects of species, foraging guilds, habitats, and ecoregions. Areas of elevated THg exposure were identified by developing a relativized estimate of fish mercury concentrations at a watershed scale that accounted for the variability associated with fish species, fish size, and site effects. THg concentrations in fish muscle ranged between 0.001 and 28.4 (μg/g wet weight (ww)) with a geometric mean of 0.17. Overall, 30% of individual fish samples and 17% of means by location exceeded the 0.30μg/g ww US EPA fish tissue criterion. Fish THg concentrations differed among habitat types, with riverine habitats consistently higher than lacustrine habitats. Importantly, fish THg concentrations were not correlated with sediment THg concentrations at a watershed scale, but were weakly correlated with sediment MeHg concentrations, suggesting that factors influencing MeHg production may be more important than inorganic Hg loading for determining fish MeHg exposure. There was large heterogeneity in fish THg concentrations across the landscape; THg concentrations were generally higher in semi-arid and arid regions such as the Great Basin and Desert Southwest, than in temperate forests. Results suggest that fish mercury exposure is widespread throughout Western US and Canada, and that species, habitat type, and region play an important role in influencing ecological risk of mercury in aquatic ecosystems.
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Affiliation(s)
- Collin A Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR 97331, USA.
| | - Joshua T Ackerman
- U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive, Suite D, Dixon, CA 95620, USA
| | - James J Willacker
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR 97331, USA
| | - Michael T Tate
- U.S. Geological Survey, Wisconsin Water Science Center, 8505 Research Way, Middleton, WI 53562, USA
| | - Michelle A Lutz
- U.S. Geological Survey, Wisconsin Water Science Center, 8505 Research Way, Middleton, WI 53562, USA
| | - Jacob A Fleck
- U.S. Geological Survey, California Water Science Center, 6000 J St. Placer Hall, Sacramento, CA 95819, USA
| | - A Robin Stewart
- U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, USA
| | - James G Wiener
- University of Wisconsin La Crosse, River Studies Center, 1725 State Street, La Crosse, WI 54601, USA
| | - David C Evers
- Biodiversity Research Institute, 276 Canco Road, Portland, ME 04103, USA
| | - Jesse M Lepak
- Colorado Parks and Wildlife, 317 West Prospect Road, Fort Collins, CO 80526, USA
| | - Jay A Davis
- San Francisco Estuary Institute, 4911 Central Ave, Richmond, CA 94804, USA
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Eagles-Smith CA, Wiener JG, Eckley CS, Willacker JJ, Evers DC, Marvin-DiPasquale M, Obrist D, Fleck JA, Aiken GR, Lepak JM, Jackson AK, Webster JP, Stewart AR, Davis JA, Alpers CN, Ackerman JT. Mercury in western North America: A synthesis of environmental contamination, fluxes, bioaccumulation, and risk to fish and wildlife. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 568:1213-1226. [PMID: 27320732 DOI: 10.1016/j.scitotenv.2016.05.094] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 05/12/2016] [Accepted: 05/13/2016] [Indexed: 05/25/2023]
Abstract
Western North America is a region defined by extreme gradients in geomorphology and climate, which support a diverse array of ecological communities and natural resources. The region also has extreme gradients in mercury (Hg) contamination due to a broad distribution of inorganic Hg sources. These diverse Hg sources and a varied landscape create a unique and complex mosaic of ecological risk from Hg impairment associated with differential methylmercury (MeHg) production and bioaccumulation. Understanding the landscape-scale variation in the magnitude and relative importance of processes associated with Hg transport, methylation, and MeHg bioaccumulation requires a multidisciplinary synthesis that transcends small-scale variability. The Western North America Mercury Synthesis compiled, analyzed, and interpreted spatial and temporal patterns and drivers of Hg and MeHg in air, soil, vegetation, sediments, fish, and wildlife across western North America. This collaboration evaluated the potential risk from Hg to fish, and wildlife health, human exposure, and examined resource management activities that influenced the risk of Hg contamination. This paper integrates the key information presented across the individual papers that comprise the synthesis. The compiled information indicates that Hg contamination is widespread, but heterogeneous, across western North America. The storage and transport of inorganic Hg across landscape gradients are largely regulated by climate and land-cover factors such as plant productivity and precipitation. Importantly, there was a striking lack of concordance between pools and sources of inorganic Hg, and MeHg in aquatic food webs. Additionally, water management had a widespread influence on MeHg bioaccumulation in aquatic ecosystems, whereas mining impacts where relatively localized. These results highlight the decoupling of inorganic Hg sources with MeHg production and bioaccumulation. Together the findings indicate that developing efforts to control MeHg production in the West may be particularly beneficial for reducing food web exposure instead of efforts to simply control inorganic Hg sources.
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Affiliation(s)
- Collin A Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR 97331, USA.
| | - James G Wiener
- University of Wisconsin La Crosse, River Studies Center, 1725 State Street, La Crosse, WI 54601, USA
| | - Chris S Eckley
- U.S. Environmental Protection Agency, Region-10, 2100 6th Ave., Suite 900, Seattle, WA 98101, USA
| | - James J Willacker
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR 97331, USA
| | - David C Evers
- Biodiversity Research Institute, 276 Canco Road, Portland, ME 04103, USA
| | | | - Daniel Obrist
- Desert Research Institute, Division of Atmospheric Sciences, 2215 Raggio Parkway, Reno, NV 89512, USA
| | - Jacob A Fleck
- U.S. Geological Survey, California Water Science Center, 6000 J St., Placer Hall, Sacramento, CA 95819, USA
| | - George R Aiken
- U.S. Geological Survey, National Research Program, 3215 Marine St., Boulder, CO 80303, USA
| | - Jesse M Lepak
- Colorado Parks and Wildlife, 317 West Prospect Road, Fort Collins, CO 80526, USA
| | - Allyson K Jackson
- Oregon State University, Department of Fisheries and Wildlife, 104 Nash Hall, Corvallis, OR 97331, USA
| | - Jackson P Webster
- University of Colorado, Civil, Environmental, and Architectural Engineering, Boulder, CO 80309, USA
| | - A Robin Stewart
- U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, USA
| | - Jay A Davis
- San Francisco Estuary Institute, 4911 Central Ave., Richmond, CA 94804, USA
| | - Charles N Alpers
- U.S. Geological Survey, California Water Science Center, 6000 J St., Placer Hall, Sacramento, CA 95819, USA
| | - Joshua T Ackerman
- U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive, Dixon, CA 95620, USA
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