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Janssen SE, Kotalik CJ, Willacker JJ, Tate MT, Pritz CMF, Nelson SJ, Krabbenhoft DP, Walters DM, Eagles-Smith CA. Geographic Drivers of Mercury Entry into Aquatic Food Webs Revealed by Mercury Stable Isotopes in Dragonfly Larvae. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58. [PMID: 39012137 PMCID: PMC11295128 DOI: 10.1021/acs.est.4c02436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 05/20/2024] [Accepted: 05/24/2024] [Indexed: 07/17/2024]
Abstract
Atmospheric mercury (Hg) emissions and subsequent transport and deposition are major concerns within protected lands, including national parks, where Hg can bioaccumulate to levels detrimental to human and wildlife health. Despite this risk to biological resources, there is limited understanding of the relative importance of different Hg sources and delivery pathways within the protected regions. Here, we used Hg stable isotope measurements within a single aquatic bioindicator, dragonfly larvae, to determine if these tracers can resolve spatial patterns in Hg sources, delivery mechanisms, and aquatic cycling at a national scale. Mercury isotope values in dragonfly tissues varied among habitat types (e.g., lentic, lotic, and wetland) and geographic location. Photochemical-derived isotope fractionation was habitat-dependent and influenced by factors that impact light penetration directly or indirectly, including dissolved organic matter, canopy cover, and total phosphorus. Strong patterns for Δ200Hg emerged in the western United States, highlighting the relative importance of wet deposition sources in arid regions in contrast to dry deposition delivery in forested regions. This work demonstrates the efficacy of dragonfly larvae as biosentinels for Hg isotope studies due to their ubiquity across freshwater ecosystems and ability to track variation in Hg sources and processing attributed to small-scale habitat and large-scale regional patterns.
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Affiliation(s)
- Sarah E. Janssen
- US
Geological Survey Upper Midwest Water Science Center, One Gifford Pinchot Drive,, Madison, Wisconsin 53726, United States
| | - Christopher J. Kotalik
- US
Geological Survey Columbia Environmental Research Center, 4200 New Haven Rd, Columbia, Missouri 65201, United States
| | - James J. Willacker
- U.S.
Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200SW Jefferson Way, Corvallis, Oregon 97331, United States
| | - Michael T. Tate
- US
Geological Survey Upper Midwest Water Science Center, One Gifford Pinchot Drive,, Madison, Wisconsin 53726, United States
| | - Colleen M. Flanagan Pritz
- National
Park Service, Air Resources Division,
P.O. Box 25287, Denver, Colorado 80225, United States
| | - Sarah J. Nelson
- Appalachian
Mountain Club, 361 Route
16, Gorham, New Hampshire 03581, United States
| | - David P. Krabbenhoft
- US
Geological Survey Upper Midwest Water Science Center, One Gifford Pinchot Drive,, Madison, Wisconsin 53726, United States
| | - David M. Walters
- US
Geological Survey Columbia Environmental Research Center, 4200 New Haven Rd, Columbia, Missouri 65201, United States
| | - Collin A. Eagles-Smith
- U.S.
Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200SW Jefferson Way, Corvallis, Oregon 97331, United States
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Nelson SJ, Willacker J, Eagles-Smith C, Flanagan Pritz C, Chen CY, Klemmer A, Krabbenhoft DP. Habitat and dissolved organic carbon modulate variation in the biogeochemical drivers of mercury bioaccumulation in dragonfly larvae at the national scale. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169396. [PMID: 38114036 DOI: 10.1016/j.scitotenv.2023.169396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/11/2023] [Accepted: 12/12/2023] [Indexed: 12/21/2023]
Abstract
We paired mercury (Hg) concentrations in dragonfly larvae with water chemistry in 29 U.S. national parks to highlight how ecological and biogeochemical context (habitat, dissolved organic carbon [DOC]) influence drivers of Hg bioaccumulation. Although prior studies have defined influences of biogeochemical variables on Hg production and bioaccumulation, it has been challenging to determine their influence across diverse habitats, regions, or biogeochemical conditions within a single study. We compared global (i.e., all sites), habitat-specific, and DOC-class models to illuminate how these controls on biotic Hg vary. Although the suite of important biogeochemical factors across all sites (e.g., aqueous Hg, DOC, sulfate [SO42-], and pH) was consistent with general findings in the literature, contrasting the restricted models revealed more nuanced controls on biosentinel Hg. Comparing habitats, aqueous (filtered) total mercury (THg) and SO42- were important in lentic systems whereas aqueous (filtered) methylmercury (MeHg), DOC, pH, and SO42- were important in lotic and wetland systems. The ability to identify important variables varied among habitats, with less certainty in lentic (model weight (W) = 0.05) than lotic (W = 0.11) or wetland habitats (W = 0.23), suggesting that biogeochemical drivers of bioaccumulation are more variable, or obscured by other aspects of Hg cycling, in these habitats. Results revealed a contrast in the importance of aqueous MeHg versus aqueous THg between DOC-classes: in low-DOC sites (<8.5 mg/L), availability of upstream inputs of MeHg appeared more important for bioaccumulation; in high-DOC sites (>8.5 mg/L) THg was more important, suggesting a link to in-situ controls on bioavailability of Hg for MeHg production. Mercury bioaccumulation (indicated by bioaccumulation factor) was more efficient in low DOC-class sites, likely due to reduced partitioning of aqueous MeHg to DOC. Together, findings highlight substantial variation in the drivers of Hg bioaccumulation and suggest consideration of these factors in natural resource management and decision-making.
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Affiliation(s)
- Sarah J Nelson
- Appalachian Mountain Club, Gorham, NH 03581, USA; University of Maine, School of Forest Resources, Orono, ME 04469, USA.
| | - James Willacker
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR 97330, USA
| | - Collin Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR 97330, USA
| | - Colleen Flanagan Pritz
- National Park Service, Air Resources Division, Natural Resource, Stewardship and Science Directorate, Lakewood, CO 80228, USA
| | | | - Amanda Klemmer
- School of Biology and Ecology, University of Maine, 5722 Deering Hall, Orono, ME 04469, USA
| | - David P Krabbenhoft
- U.S. Geological Survey, Upper Midwest Water Science Center, 1 Gifford Pinchot Dr., Madison, WI 53726, USA
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Ma T, Ding Y, Xu F, Zhang C, Zhou M, Tang Y, Chen Y, Wen Y, Chen R, Tang B, Wang S. Effects of acute and chronic chromium stress on the expression of heat shock protein genes and activities of antioxidant enzymes in larvae of Orthetrum albistylum. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 340:122712. [PMID: 37813144 DOI: 10.1016/j.envpol.2023.122712] [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: 07/10/2023] [Revised: 10/06/2023] [Accepted: 10/06/2023] [Indexed: 10/11/2023]
Abstract
The dragonfly species Orthetrum albistylum, can accumulate heavy metals from its aquatic environment and thus serves as a biological indicator for monitoring and evaluating water quality. Heat shock proteins (HSPs) play important biological roles in resistance to various types of environmental stress. The full-length cDNA sequences of the heat shock cognate (hsc) 70 and heat shock protein (hsp) 70 genes were cloned from O. albistylum larvae. Relative levels of expression of hsc70 and hsp70 in the head, epidermis, midgut, and adipose tissue were measured by qRT-PCR after chronic and acute contamination of 5-8 instar larvae with chromium (Cr) solution, and under control conditions. Activities of superoxide dismutase (SOD) and catalase (CAT) in chronically contaminated larvae were also measured. Phylogenetic analysis revealed that the cloned hsc70 and hsp70 genes were highly homologous to known HSP70 family members reported in other insects. The mRNA levels of hsc70 and hsp70 did not differ significantly in various larval tissues. Under chronic chromium stress, hsc70 and hsp70 expression were upregulated to a maximum and then downregulated; hsp70 mRNA levels were higher than those of hsc70 at all concentrations of chromium. Under acute chromium stress, hsc70 expression was inhibited at low chromium concentrations and upregulated at chromium concentrations higher than 125 mg/L. However, hsp70 expression was higher than that in the control group and markedly higher than that of hsc70. Changes in SOD and CAT activities displayed consistent trends for different chronic chromium concentrations, first increasing and then decreasing over time. Collectively, these findings demonstrated the response of the HSP family of genes and antioxidant enzymes following exposure to heavy metal stress, as well as their potential applicability as biomarkers for monitoring environmental pollutants.
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Affiliation(s)
- Tingting Ma
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 311121, China
| | - Yanjuan Ding
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 311121, China
| | - Fengjiao Xu
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 311121, China
| | - Chen Zhang
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 311121, China
| | - Min Zhou
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 311121, China
| | - Ya Tang
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 311121, China
| | - Yanrong Chen
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 311121, China
| | - Yating Wen
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 311121, China
| | - Rufei Chen
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 311121, China
| | - Bin Tang
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 311121, China
| | - Shigui Wang
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 311121, China.
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Noor-Ul-Islam H, Khan K, Zia SA, Naeem M, Shams WA. Heavy Metals Accumulation in Dragonflies (Odonata) and Their Habitats in District Swabi, Khyber Pakhtunkhwa, Pakistan: Assessing Dragonfly Bionomics in the Region. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2021; 107:838-847. [PMID: 34297168 DOI: 10.1007/s00128-021-03338-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] [Received: 02/03/2021] [Accepted: 07/12/2021] [Indexed: 06/13/2023]
Abstract
The current study aimed to examine the bionomics of dragonflies and heavy metal accumulation in their bodies and environment (sediments and water) from district Swabi, Khyber Pakhtunkhwa, Pakistan. A total of 1683 dragonflies were collected from May to September, 2018 in 4 tehsils (administrative subdivisions) of district. Orthetrum pruinosum neglectum was the most abundant species followed by O. anceps and O. chrysostigma luzonicum. Highest abundance was observed in July and August corresponding to maximum temperature and rainfall. Dragonflies displayed preferable abundance within agricultural lands and on elevation ranging from 206 to 506 m. Heavy metal analysis of sediments and water samples from 4 tehsils showed significant differences in mean concentrations of Pb, Zn, Cu, and Fe. Abundance among districts was negatively associated with Fe levels in water while the species diversity had a significant positive relationship with Fe in sediments. Accumulation of metals in each body part significantly varied among species. N. tullia tullia and O. anceps specifically demonstrated their tolerance to high concentrations of heavy metals.
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Affiliation(s)
- Hajra Noor-Ul-Islam
- Department of Zoology, Abdul Wali Khan University Mardan, Mardan, Khyber Pakhtunkhwa, Pakistan
| | - Khurshaid Khan
- Department of Zoology, Abdul Wali Khan University Mardan, Mardan, Khyber Pakhtunkhwa, Pakistan.
| | - Syed Ahmed Zia
- Institute of Plant and Environmental Protection, National Agriculture Research Centre, Islamabad, Pakistan
| | - Muhammad Naeem
- Department of Chemistry, Abdul Wali Khan University Mardan, Mardan, Khyber Pakhtunkhwa, Pakistan
| | - Waqas Ahmad Shams
- Department of Zoology, Abdul Wali Khan University Mardan, Mardan, Khyber Pakhtunkhwa, Pakistan
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5
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Wu G, Tang S, Han J, Li C, Liu L, Xu X, Xu Z, Chen Z, Wang Y, Qiu G. Distributions of Total Mercury and Methylmercury in Dragonflies from a Large, Abandoned Mercury Mining Region in China. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2021; 81:25-35. [PMID: 34027570 DOI: 10.1007/s00244-021-00854-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 05/02/2021] [Indexed: 06/12/2023]
Abstract
Dragonflies (Order Odonata) often are considered to be biosentinels of environmental contamination, e.g., heavy metals and/or persistent organic pollutants (POPs). Dragonflies (n = 439) belonging to 15 species of 8 genera were collected from an abandoned mercury (Hg) mining region in China to investigate the bioaccumulation of total Hg (THg) and methylmercury (MeHg). THg and MeHg concentrations in dragonflies varied widely within ranges of 0.06-19 mg/kg (average: 1.5 ± 2.2 mg/kg) and 0.02-5.7 mg/kg (average: 0.75 ± 0.65 mg/kg), respectively. THg and MeHg were positively correlated with bodyweight (THg: r2 = 0.10, P = 0.000; MeHg: r2 = 0.09, P = 0.000). Significant variations were observed among species, with the highest MeHg value (in Orthetrum triangulare) was fivefold higher than the lowest (in Pantala flavescens). These variations were consistent with those of nitrogen isotope (δ15N) values, indicating that increased δ15N, i.e., trophic levels, may reflect increased exposure and uptake of biomagnifying MeHg in dragonflies. A toxicological risk assessment found hazard quotients for specialist dragonfly-consuming birds of up to 7.2, which is 2.4 times greater than the permissible limit of 3, suggesting a potential toxicological risk of exposure.
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Affiliation(s)
- Gaoen Wu
- Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, 454003 , China
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Shunlin Tang
- Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, 454003 , China.
| | - Jialiang Han
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chan Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
- School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China
| | - Lin Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaohang Xu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Zhidong Xu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Zhuo Chen
- School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China
| | - Yajie Wang
- College of Food Science, Guizhou Medical University, Guiyang, 550025, China
| | - Guangle Qiu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
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6
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Bracey AM, Etterson MA, Strand FC, Matteson SW, Niemi GJ, Cuthbert FJ, Hoffman JC. Foraging Ecology Differentiates Life Stages and Mercury Exposure in Common Terns (Sterna hirundo). INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2021; 17:398-410. [PMID: 32930480 PMCID: PMC8108127 DOI: 10.1002/ieam.4341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/19/2020] [Accepted: 09/03/2020] [Indexed: 05/21/2023]
Abstract
Some populations of common terns (Sterna hirundo) breeding at inland lakes in North America are declining, including the Laurentian Great Lakes. Terns nesting at inland colonies forage in freshwater during the breeding season and primarily in coastal marine environments during the nonbreeding season. As piscivores, they are susceptible to dietary Hg exposure. To characterize patterns of Hg exposure in this population, we 1) quantified within and among season differences in total mercury (THg) concentrations (μg/g) in blood and feathers at 2 Lake Superior breeding colonies, and 2) documented spatial and temporal variation in exposure by studying adult foraging ecology using geospatial tracking devices and stable isotopes. We used general linear models to assess the relationship between isotopic composition and THg concentrations in bird tissues relative to sex, age, colony location, and season. The THg concentrations were lowest in winter-grown feathers (geometric mean [95% confidence limits]): 1.32 (1.09-1.59) μg/g dw (n = 60), higher at the more industrially influenced colony (chick feathers: 4.95 [4.62-5.37] μg/g dw [n = 20]), and increased with a riverine-based diet. During the breeding season, Hg exposure varied along a gradient from lake to river, with adult females having lower blood THg concentrations than males (females: 0.83 [0.67-1.03]) μg/g ww (n = 7); males: 1.15 (0.92-1.45) μg/g ww (n = 5). Stable isotope values suggested adults obtained 42 ± 12% (n = 12) of their diet from the river during incubation, which was validated with tracking data. During chick-rearing, chicks obtained 68 ± 19% (n = 44) of their diet from the river. Our results indicate colony location, foraging behavior, and season influenced Hg exposure for these Lake Superior colonies and underscores the importance of local contamination with respect to exposure. Integr Environ Assess Manag 2021;17:398-410. © 2020 SETAC.
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Affiliation(s)
- Annie M. Bracey
- Department of Fisheries, Wildlife and Conservation Biology, University of Minnesota, 2003 Upper Buford Circle, St. Paul, Minnesota, 55108, USA
- Natural Resources Research Institute, University of Minnesota, 5013 Miller Trunk Hwy, Duluth, Minnesota, 55811, USA
- Annie Bracey, Natural Resources Research Institute, 5013 Miller Trunk Hwy, Duluth, MN 55811, 218-788-2649,
| | - Matthew A. Etterson
- US EPA Office of Research and Development, Center for Computational Toxicology and Exposure, Great Lakes Toxicology and Ecology Division, 6201 Congdon Blvd, Duluth, Minnesota, 55804, USA
| | - Frederick C. Strand
- Wisconsin Department of Natural Resources, 6250 Ranger Road, Brule, Wisconsin, 54820, USA
- Retired
| | - Sumner W. Matteson
- Wisconsin Department of Natural Resources, 101 South Webster Street, GEF 2, Madison, Wisconsin, 53707, USA
| | - Gerald J. Niemi
- Natural Resources Research Institute, University of Minnesota, 5013 Miller Trunk Hwy, Duluth, Minnesota, 55811, USA
| | - Francesca J. Cuthbert
- Department of Fisheries, Wildlife and Conservation Biology, University of Minnesota, 2003 Upper Buford Circle, St. Paul, Minnesota, 55108, USA
| | - Joel C. Hoffman
- US EPA Office of Research and Development, Center for Computational Toxicology and Exposure, Great Lakes Toxicology and Ecology Division, 6201 Congdon Blvd, Duluth, Minnesota, 55804, USA
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Riva-Murray K, Bradley PM, Brigham ME. Methylmercury-total mercury ratios in predator and primary consumer insects from Adirondack streams (New York, USA). ECOTOXICOLOGY (LONDON, ENGLAND) 2020; 29:1644-1658. [PMID: 32180092 DOI: 10.1007/s10646-020-02191-7] [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] [Accepted: 02/28/2020] [Indexed: 06/10/2023]
Abstract
Mercury (Hg) is a global pollutant that affects biota in remote settings due to atmospheric deposition of inorganic Hg, and its conversion to methylmercury (MeHg), the bioaccumulating and toxic form. Characterizing biotic MeHg is important for evaluating aquatic ecosystem responses to changes in Hg inputs. Aquatic insects possess many qualities desired for MeHg biomonitoring, but are not widely used, largely because of limited information regarding percentages of total mercury (THg) composed of MeHg (i.e., MeHg%) in various taxa. Here, we examine taxonomic, spatial, and seasonal variation in MeHg% of stream-dwelling predator and primary-consumer insects from nine streams in the Adirondack region (NY, USA). Predator MeHg% was high (median 94%) and did not differ significantly among five taxa. MeHg% in selected dragonflies (the most abundant predators, Odonata: Aeshnidae and Libellulidae) exhibited little seasonal and spatial variation, and THg concentration was strongly correlated with aqueous (filtered) MeHg (FMeHg; rs = 0.76). In contrast, MeHg% in primary consumers-shredders (northern caddisflies [Trichoptera: Limnephilidae]) and scrapers (flathead mayflies [Ephemeroptera: Heptageniidae]), were lower (medians 52% and 35%, respectively), and differed significantly between taxa, among sites, and seasonally. Correlations of THg with FMeHg were weak (shredders, rs = 0.45, p = 0.09) or not significant (scrapers, p = 0.89). The higher MeHg% of predators corresponded with their higher trophic positions (indicated by nitrogen stable isotopes). Results suggest obligate predators hold the most promise for the use of THg as a surrogate for MeHg biomonitoring with aquatic insects within the Adirondack region.
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Affiliation(s)
| | - Paul M Bradley
- U.S. Geological Survey, 720 Gracern Road, Columbia, SC, 29210, USA
| | - Mark E Brigham
- U.S. Geological Survey, 2280 Woodale Drive, Mounds View, MN, 55112, USA
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Millard G, Driscoll C, Montesdeoca M, Yang Y, Taylor M, Boucher S, Shaw A, Richter W, Paul E, Parker C, Yokota K. Patterns and trends of fish mercury in New York State. ECOTOXICOLOGY (LONDON, ENGLAND) 2020; 29:1709-1720. [PMID: 31955284 DOI: 10.1007/s10646-020-02163-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/04/2020] [Indexed: 06/10/2023]
Abstract
In the mid-2000s a survey was conducted to evaluate fish mercury in lakes across New York State. Approximately 10 years later a second survey examining adult sportfish from 103 lakes and reservoirs was conducted to evaluate the response of fish mercury to recent declines in US mercury emissions. Of those lakes, 43 were part of the earlier survey and were examined to determine if mercury concentrations in four popular sport species, Yellow Perch, Walleye, and Small- and Largemouth Bass, declined in response to decreasing emissions. Water samples were also collected at 35 of these lakes and analyzed for mercury, methylmercury and other analytes. The Adirondack and Catskill regions remain biological mercury hotspots with elevated concentrations in fish. The most widely sampled species, Yellow Perch, showed significant increases in mercury in the Northeast and West regions of New York State over the past decade. The increases in Yellow Perch mercury is not consistent with significant reductions in water concentrations of both total and methylmercury observed corresponding in lake water samples. This discrepancy suggests watershed and in-lake processes beyond mercury emissions, such as recovery from acid deposition, impacts from climate change, or changes in food web structure may be controlling fish mercury concentrations. These results demonstrate a need for a consistent, long-term program to monitor fish mercury to inform the status of mercury contamination in New York State.
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Affiliation(s)
- Geoffrey Millard
- Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY, 13244, USA.
- National Risk Management Research Laboratory, US Environmental Protection Agency, Cincinnati, OH, 45244, USA.
| | - Charles Driscoll
- Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY, 13244, USA
| | - Mario Montesdeoca
- Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY, 13244, USA
| | - Yang Yang
- Department of Forest and Natural Resources Management, State University of New York College of Environmental Science and Forestry, Syracuse, NY, 13210, USA
| | - Mariah Taylor
- Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY, 13244, USA
| | - Stephen Boucher
- Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY, 13244, USA
| | - Amy Shaw
- Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY, 13244, USA
| | - Wayne Richter
- Division of Fish and Wildlife, New York State Department of Environmental Conservation, Albany, NY, 12233, USA
- Department of Biology, Skidmore College, Saratoga Springs, NY, 12866, USA
| | - Eric Paul
- Division of Fish and Wildlife, New York State Department of Environmental Conservation, Rome, NY, 13440, USA
| | - Colleen Parker
- Department of Biology, State University of New York College at Oneonta, Oneonta, NY, 13820, USA
| | - Kiyoko Yokota
- Department of Biology, State University of New York College at Oneonta, Oneonta, NY, 13820, USA
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9
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Nelson SJ, Chen CY, Kahl JS. Dragonfly larvae as biosentinels of Hg bioaccumulation in Northeastern and Adirondack lakes: relationships to abiotic factors. ECOTOXICOLOGY (LONDON, ENGLAND) 2020; 29:1659-1672. [PMID: 31883061 PMCID: PMC8418898 DOI: 10.1007/s10646-019-02149-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/05/2019] [Indexed: 05/28/2023]
Abstract
Mercury (Hg) is a toxic pollutant, widespread in northeastern US ecosystems. Resource managers' efforts to develop fish consumption advisories for humans and to focus conservation efforts for fish-eating wildlife are hampered by spatial variability. Dragonfly larvae can serve as biosentinels for Hg given that they are widespread in freshwaters, long-lived, exhibit site fidelity, and bioaccumulate relatively high mercury concentrations, mostly as methylmercury (88% ± 11% MeHg in this study). We sampled lake water and dragonfly larvae in 74 northeastern US lakes that are part of the US EPA Long-Term Monitoring Network, including 45 lakes in New York, 43 of which are in the Adirondacks. Aqueous dissolved organic carbon (DOC) and total Hg (THg) were strongly related to MeHg in lake water. Dragonfly larvae total mercury ranged from 0.016-0.918 μg/g, dw across the study area; Adirondack lakes had the minimum and maximum concentrations. Aqueous MeHg and dragonfly THg were similar between the Adirondack and Northeast regions, but a majority of lakes within the highest quartile of dragonfly THg were in the Adirondacks. Using landscape, lake chemistry, and lake morphometry data, we evaluated relationships with MeHg in lake water and THg in dragonfly larvae. Lakewater DOC and lake volume were strong predictors for MeHg in water. Dragonfly THg Bioaccumulation Factors (BAFs, calculated as [dragonfly THg]:[aqueous MeHg]) increased as lake volume increased, suggesting that lake size influences Hg bioaccumulation or biomagnification. BAFs declined with increasing DOC, supporting a potential limiting effect for MeHg bioavailability with higher DOC.
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Affiliation(s)
- Sarah J Nelson
- School of Forest Resources, University of Maine, 5755 Nutting Hall, Orono, ME, 04469-5755, USA.
- Appalachian Mountain Club, PO Box 298, Route 16, Gorham, NH, 03581, USA.
| | - Celia Y Chen
- Department of Biological Sciences, Dartmouth College, HB 6044, Class of '78 Life Sciences Center, Hanover, NH, 03755, USA
| | - Jeffrey S Kahl
- Thomas College, School of Arts and Sciences, 180 West River Road, Waterville, ME, 04901, USA
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10
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Riparian and in-channel habitat properties linked to dragonfly emergence. Sci Rep 2020; 10:17665. [PMID: 33077819 PMCID: PMC7573607 DOI: 10.1038/s41598-020-74429-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 09/23/2020] [Indexed: 11/08/2022] Open
Abstract
In freshwater ecosystems, habitat alteration contributes directly to biodiversity loss. Dragonflies are sentinel species that are key invertebrate predators in both aquatic (as larvae) and terrestrial ecosystems (as adults). Understanding the habitat factors affecting dragonfly emergence can inform management practices to conserve habitats supporting these species and the functions they perform. Transitioning from larvae to adults, dragonflies leave behind larval exoskeletons (exuviae), which reveal information about the emergent population without the need for sacrificing living organisms. Capitalizing on Atlantic Canada's largest freshwater wetland, the Grand Lake Meadows (GLM) and the associated Saint John/Wolastoq River (SJWR), we studied the spatial (i.e., across the mainstem, tributary, and wetland sites) and temporal (across 3 years) variation in assemblages of emergent dragonflies (Anisoptera) and assessed the relative contribution of aquatic and terrestrial factors structuring these assemblages. The GLM complex, including the lotic SJWR and its tributaries and associated lentic wetlands, provided a range of riparian and aquatic habitat variability ideal for studying dragonfly emergence patterns across a relatively homogenous climatic region. Emergent dragonfly responses were associated with spatial, but not temporal, variation. Additionally, dragonfly communities were associated with both aquatic and terrestrial factors, while diversity was primarily associated with terrestrial factors. Specific terrestrial factors associated with the emergence of the dragonfly community included canopy cover and slope, while aquatic factors included water temperature, dissolved oxygen, and baseflow. Our results indicate that management of river habitats for dragonfly conservation should incorporate riparian habitat protection while maintaining aquatic habitat and habitat quality.
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11
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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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12
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Broadley HJ, Cottingham KL, Baer NA, Weathers KC, Ewing HA, Chaves-Ulloa R, Chickering J, Wilson AM, Shrestha J, Chen CY. Factors affecting MeHg bioaccumulation in stream biota: the role of dissolved organic carbon and diet. ECOTOXICOLOGY (LONDON, ENGLAND) 2019; 28:949-963. [PMID: 31410744 PMCID: PMC6814552 DOI: 10.1007/s10646-019-02086-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/22/2019] [Indexed: 05/15/2023]
Abstract
The bioaccumulation of the neurotoxin methylmercury (MeHg) in freshwater ecosystems is thought to be mediated by both water chemistry (e.g., dissolved organic carbon [DOC] and dissolved mercury [Hg]) and diet (e.g., trophic position and diet composition). Hg in small streams is of particular interest given their role as a link between terrestrial and aquatic processes. Terrestrial processes determine the quantity and quality of streamwater DOC, which in turn influence the quantity and bioavailability of dissolved MeHg. To better understand the effects of water chemistry and diet on Hg bioaccumulation in stream biota, we measured DOC and dissolved Hg in stream water and mercury concentration in three benthic invertebrate taxa and three fish species across up to 12 tributary streams in a forested watershed in New Hampshire, USA. As expected, dissolved total mercury (THg) and MeHg concentrations increased linearly with DOC. However, mercury concentrations in fish and invertebrates varied non-linearly, with maximum bioaccumulation at intermediate DOC concentrations, which suggests that MeHg bioavailability may be reduced at high levels of DOC. Further, MeHg and THg concentrations in invertebrates and fish, respectively, increased with δ15N (suggesting trophic position) but were not associated with δ13C. These results show that even though MeHg in water is strongly determined by DOC concentrations, mercury bioaccumulation in stream food webs is the result of both MeHg availability in stream water and trophic position.
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Affiliation(s)
- Hannah J Broadley
- Department of Environmental Conservation, University of Massachusetts, Amherst, MA, 01003, USA.
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA.
- Environmental Studies Program, Bates College, Lewiston, ME, 04240, USA.
| | | | - Nicholas A Baer
- Department of Natural and Environmental Sciences, Colby-Sawyer College, New London, NH, 03257, USA
| | | | - Holly A Ewing
- Environmental Studies Program, Bates College, Lewiston, ME, 04240, USA
| | - Ramsa Chaves-Ulloa
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA
- Department of General Education, Western Governors University, Salt Lake City, UT, USA
| | - Jessica Chickering
- Department of Natural and Environmental Sciences, Colby-Sawyer College, New London, NH, 03257, USA
| | - Adam M Wilson
- Department of Natural and Environmental Sciences, Colby-Sawyer College, New London, NH, 03257, USA
| | - Jenisha Shrestha
- Department of Natural and Environmental Sciences, Colby-Sawyer College, New London, NH, 03257, USA
| | - Celia Y Chen
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA
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13
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Poste AE, Hoel CS, Andersen T, Arts MT, Færøvig PJ, Borgå K. Terrestrial organic matter increases zooplankton methylmercury accumulation in a brown-water boreal lake. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 674:9-18. [PMID: 31003089 DOI: 10.1016/j.scitotenv.2019.03.446] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 03/24/2019] [Accepted: 03/28/2019] [Indexed: 06/09/2023]
Abstract
Increases in terrestrial organic matter (tOM) transport from catchments to boreal lakes can affect methylmercury (MeHg) accumulation in aquatic biota both directly by increasing concentrations of aqueous MeHg, and indirectly through effects on MeHg bioavailability and on energy pathways in the lower food web. We carried out a detailed seasonal study of water chemistry, zooplankton diet, and MeHg accumulation in zooplankton in two lakes with contrasting tOM concentrations. Between-lake differences explained 51% of the variability in our water chemistry data, with no observed effect of season or sampling depth, contrary to our expectations. Higher tOM was correlated with higher aqueous Hg concentrations, lower areal pelagic primary productivity, and an increased contribution of terrestrial particles to pelagic particulate organic matter. Based on dietary marker analysis (δ13C, δ15N, and fatty acid [FA] composition), zooplankton diet was strongly linked to feeding mechanism, with dietary reliance on phytoplankton highest in the selective-feeding calanoid copepods, and lowest in filter feeding cladocerans. Zooplankton dietary reliance on phytoplankton and their concentrations of high-quality lipids, including polyunsaturated fatty acids, were higher in the clear-water lake than in the brown-water lake, where bacterial and terrestrial food sources were more prevalent. MeHg was highest in zooplankton from the brown-water lake, with highest concentrations in the 200-500 μm zooplankton size fraction for both lakes. Contrary to our expectations, there was no effect of season on zooplankton dietary markers or MeHg. Our results suggest that, overall, higher tOM results in higher MeHg concentrations in water and zooplankton, and reduces zooplankton dietary reliance on phytoplankton. Increased tOM thus leads to a decrease in the nutritional quality of zooplankton (i.e. higher MeHg concentrations, and lower concentrations of essential fatty acids), which may cascade up the food web with negative implications for higher trophic levels.
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Affiliation(s)
- Amanda E Poste
- Norwegian Institute for Water Research, Gaustadalléen 21, 0349 Oslo, Norway.
| | - Cathrine Skaar Hoel
- Department of Bioscience, University of Oslo, Blindernveien 31, 0371 Oslo, Norway
| | - Tom Andersen
- Department of Bioscience, University of Oslo, Blindernveien 31, 0371 Oslo, Norway
| | - Michael T Arts
- Department of Chemistry and Biology, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada
| | - Per-Johan Færøvig
- Department of Bioscience, University of Oslo, Blindernveien 31, 0371 Oslo, Norway
| | - Katrine Borgå
- Department of Bioscience, University of Oslo, Blindernveien 31, 0371 Oslo, Norway.
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14
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Lei P, Nunes LM, Liu YR, Zhong H, Pan K. Mechanisms of algal biomass input enhanced microbial Hg methylation in lake sediments. ENVIRONMENT INTERNATIONAL 2019; 126:279-288. [PMID: 30825746 DOI: 10.1016/j.envint.2019.02.043] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 02/12/2019] [Accepted: 02/16/2019] [Indexed: 05/25/2023]
Abstract
Eutrophication is a major environmental concern in lake systems, impacting the ecological risks of contaminants and drinking water safety. It has long been believed that eutrophication and thus algal blooms would reduce methylmercury (MeHg) levels in water, as well as MeHg bioaccumulation and trophic transfer (e.g., by growth dilution). In this study, however, we demonstrated that algae settlement and decomposition after algal blooms increased MeHg levels in sediments (54-514% higher), as evidenced by the results from sediments in 10 major lakes in China. These could in turn raise concerns about enhanced trophic transfer of MeHg and deterioration of water quality after algal blooms, especially considering that 9 out of the 10 examined lakes also serve as drinking water sources. The enhanced microbial MeHg production in sediments could be explained by the algal organic matter (AOM)-enhanced abundances of microbial methylators as well as the input of algae-inhabited microbes into sediments, but not Hg speciation in sediments: (1) Several AOM components (e.g., aromatic proteins and soluble microbial by product-like material with generally low molecular weights), rather than the bulk AOM, played key roles in enhancing the abundances of microbial methylators. The copies of Archaea-hgcA methylation genes were 51-397% higher in algae-added sediments; thus, MeHg production was also higher. (2) Input of algal biomass-inhabited microbial methylators contributed to 2-21% of total Archaea-hgcA in the 10 lake sediments with added algal biomass. (3) However, AOM-induced changes in Hg speciation, with implications on Hg availability to microbial methylators, played a minor role in enhancing microbial Hg methylation in sediments as seen in X-ray absorption near edge structure (XANES) data. Our results suggest the need to better understand the biogeochemistry and risks of contaminants in eutrophic lakes, especially during the period of algae settlement and decomposition following algal blooms.
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Affiliation(s)
- Pei Lei
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China; Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China; State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210046, China
| | - Luís M Nunes
- Civil Engineering Research and Innovation for Sustainability Center, University of Algarve, Faro, Portugal
| | - Yu-Rong Liu
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Huan Zhong
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210046, China; Environmental and Life Science Program (EnLS), Trent University, Peterborough, Ontario, Canada.
| | - Ke Pan
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China.
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15
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Braaten HFV, de Wit HA, Larssen T, Poste AE. Mercury in fish from Norwegian lakes: The complex influence of aqueous organic carbon. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 627:341-348. [PMID: 29426157 DOI: 10.1016/j.scitotenv.2018.01.252] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 01/24/2018] [Accepted: 01/24/2018] [Indexed: 06/08/2023]
Abstract
Mercury (Hg) concentrations in water and biota are often positively correlated to organic matter (OM), typically measured as total or dissolved organic carbon (TOC/DOC). However, recent evidence suggests that higher OM concentrations inhibit bioaccumulation of Hg. Here, we test how TOC impacts the Hg accumulation in fish in a synoptic study of Methyl-Hg (MeHg) in water and total Hg (THg) in perch (Perca fluviatilis) in 34 boreal lakes in southern Norway. We found that aqueous MeHg (r2 = 0.49, p < 0.0001) and THg (r2 = 0.69, p < 0.0001), and fish THg (r2 = 0.26, p < 0.01) were all positively related with TOC. However, we found declining MeHg bioaccumulation factors (BAFMeHg) for fish with increasing TOC concentrations. The significant correlation between fish THg concentrations and aqueous TOC suggests that elevated fish Hg levels in boreal regions are associated with humic lakes. The declining BAFMeHg with increasing TOC suggest that increased OM promotes increased aqueous Hg concentrations, but lowers relative MeHg bioaccumulation. A mechanistic understanding of the response from OM on BAFMeHg might be found in the metal-complexation properties of OM, where OM complexation of metals reduces their bioavailability. Hence, suggesting that MeHg bioaccumulation becomes less effective at higher TOC, which is particularly relevant when assessing potential responses of fish Hg to predicted future changes in OM inputs to boreal ecosystems. Increased browning of waters may affect fish Hg in opposite directions: an increase of food web exposure to aqueous Hg, and reduced bioavailability of Hg species. However, the negative relationship between BAFMeHg and TOC is challenging to interpret, and carries a great deal of uncertainty, since this relationship may be driven by the underlying correlation between TOC and MeHg (i.e. spurious correlations). Our results suggest that the trade-off between Hg exposure and accumulation will have important implications for the effects of lake browning on Hg transport, bioavailability, and trophodynamics.
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Affiliation(s)
| | - Heleen A de Wit
- Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, N-0349 Oslo, Norway
| | - Thorjørn Larssen
- Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, N-0349 Oslo, Norway
| | - Amanda E Poste
- Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, N-0349 Oslo, Norway
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16
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Lescord GL, Emilson EJS, Johnston TA, Branfireun BA, Gunn JM. Optical Properties of Dissolved Organic Matter and Their Relation to Mercury Concentrations in Water and Biota Across a Remote Freshwater Drainage Basin. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:3344-3353. [PMID: 29444573 DOI: 10.1021/acs.est.7b05348] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Dissolved organic matter (DOM) includes an array of carbon-based compounds that vary in size and structure and have complex interactions with mercury (Hg) cycling in aquatic systems. While many studies have examined the relationship between dissolved organic carbon concentrations ([DOC]) and methyl Hg bioaccumulation, few studies have considered the effects of DOM composition (e.g., protein-content, aromaticity). The goal of this study was to explore the relationships between total and methyl [Hg] in water, invertebrates, and fish and optically derived measures of DOM composition from 47 lake and river sites across a boreal watershed. Results showed higher aqueous total [Hg] in systems with more aromatic DOM and higher [DOC], potentially due to enhanced transport from upstream or riparian areas. Methyl [Hg] in biota were all positively related to the amount of microbial-based DOM and, in some cases, to the proportions of labile and protein-like DOM. These results suggest that increased Hg bioaccumulation is related to the availability of labile DOM, potentially due to enhanced Hg methylation. DOM composition explained 68% and 54% more variability in [Hg] in surface waters and large-bodied fish, respectively, than [DOC] alone. These results show that optical measures of DOM characteristics are a valuable tool for understanding DOM-Hg biogeochemistry.
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Affiliation(s)
- Gretchen L Lescord
- Laurentian University , 935 Ramsey Lake Road , Sudbury , Ontario P3E 2C6 , Canada
| | - Erik J S Emilson
- Natural Resources Canada , Great Lakes Forestry Centre , 1219 Queen Street East , Sault Sainte Marie , Ontario P6A 2E5 , Canada
| | - Tom A Johnston
- Laurentian University , 935 Ramsey Lake Road , Sudbury , Ontario P3E 2C6 , Canada
- Ontario Ministry of Natural Resources and Forestry , Sudbury , Ontario P3E 2C6 , Canada
| | | | - John M Gunn
- Laurentian University , 935 Ramsey Lake Road , Sudbury , Ontario P3E 2C6 , Canada
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17
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Klapstein SJ, Ziegler SE, Risk DA, O'Driscoll NJ. Quantifying the effects of photoreactive dissolved organic matter on methylmercury photodemethylation rates in freshwaters. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2017; 36:1493-1502. [PMID: 27859609 DOI: 10.1002/etc.3690] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 10/21/2016] [Accepted: 11/15/2016] [Indexed: 06/06/2023]
Abstract
The present study examined potential effects of seasonal variations in photoreactive dissolved organic matter (DOM) on methylmercury (MeHg) photodemethylation rates in freshwaters. A series of controlled experiments was carried out using natural and photochemically preconditioned DOM in water collected from 1 lake in June, August, and October. Natural DOM concentrations doubled between June and August (10.2-21.2 mg C L-1 ) and then remained stable into October (19.4 mg C L-1 ). Correspondingly, MeHg concentrations peaked in August (0.42 ng L-1 ), along with absorbances at 350 nm and 254 nm. Up to 70% of MeHg was photodemethylated in the short 48-h irradiation experiments, with June having significantly higher rates than the other sampling months (p < 0.001). Photodemethylation rate constants were not affected by photoreactive DOM, nor were they affected by initial MeHg concentrations (p > 0.10). However, MeHg photodemethylation efficiencies (quantified in moles MeHg lost/moles photon absorbed) were higher in treatments with less photoreactive DOM. Congruently, MeHg photodemethylation efficiencies also decreased over summer by up to 10 times across treatments in association with increased photoreactive DOM, and were negatively correlated with DOM concentration. These results suggest that an important driver of MeHg photodemethylation is the interplay between MeHg and DOM, with greater potential for photodemethylation in freshwaters with more photobleached DOM and lower DOM content. Environ Toxicol Chem 2017;36:1493-1502. © 2016 SETAC.
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Affiliation(s)
- Sara J Klapstein
- Department of Environmental Science, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
- Department of Earth and Environmental Science, Acadia University, Wolfville, Nova Scotia, Canada
| | - Susan E Ziegler
- Department of Environmental Science, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - David A Risk
- Department of Earth Sciences, St. Francis Xavier University, Antigonish, Nova Scotia, Canada
| | - Nelson J O'Driscoll
- Department of Earth and Environmental Science, Acadia University, Wolfville, Nova Scotia, Canada
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18
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Berndt ME, Rutelonis W, Regan CP. A comparison of results from a hydrologic transport model (HSPF) with distributions of sulfate and mercury in a mine-impacted watershed in northeastern Minnesota. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2016; 181:74-79. [PMID: 27318875 DOI: 10.1016/j.jenvman.2016.05.067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 05/25/2016] [Accepted: 05/26/2016] [Indexed: 06/06/2023]
Abstract
The St. Louis River watershed in northeast Minnesota hosts a major iron mining district that has operated continuously since the 1890s. Concern exists that chemical reduction of sulfate that is released from mines enhances the methylation of mercury in the watershed, leading to increased mercury concentrations in St. Louis River fish. This study tests this idea by simulating the behavior of chemical tracers using a hydrologic flow model (Hydrologic Simulation Program FORTRAN; HSPF) and comparing the results with measured chemistry from several key sites located both upstream and downstream from the mining region. It was found that peaks in measured methylmercury (MeHg), total mercury (THg), dissolved organic carbon (DOC), and dissolved iron (Fe) concentrations correspond to periods in time when modeled recharge was dominated by active groundwater throughout the watershed. This helps explain why the timing and size of the MeHg peaks was nearly the same at sites located just upstream and downstream from the mining region. Both the modeled percentages of mine water and the measured sulfate concentrations were low and computed transit times were short for sites downstream from the mining region at times when measured MeHg reached its peak. Taken together, the data and flow model imply that MeHg is released into groundwater that recharges the river through riparian sediments following periods of elevated summer rainfall. The measured sulfate concentrations at the upstream site reached minimum concentrations of approximately 1 mg/L just as MeHg reached its peak, suggesting that reduction of sulfate from non-point sources exerts an important influence on MeHg concentrations at this site. While mines are the dominant source of sulfate to sites downstream from them, it appears that the background sulfate which is present at only 1-6 mg/L, has the largest influence on MeHg concentrations. This is because point sourced sulfate is transported generally under oxidized conditions and is not flushed through riparian sediments in a gaining stream watershed system.
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Affiliation(s)
- Michael E Berndt
- Minnesota Department of Natural Resources, 500 Lafayette Road, St. Paul, MN, 55155, USA.
| | - Wes Rutelonis
- University of Minnesota, Earth Sciences Department, 310 Pillsbury Drive SE, Minneapolis, MN, 55455, USA
| | - Charles P Regan
- Minnesota Pollution Control Agency, 520 Lafayette Road, St. Paul, MN, 55155, USA
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19
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Johnson NW, Mitchell CPJ, Engstrom DR, Bailey LT, Coleman Wasik JK, Berndt ME. Methylmercury production in a chronically sulfate-impacted sub-boreal wetland. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2016; 18:725-734. [PMID: 27224550 DOI: 10.1039/c6em00138f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Increased deposition of atmospheric sulfate exacerbates methylmercury (MeHg) production in freshwater wetlands by stimulating methylating bacteria, but it is unclear how methylation in sub-boreal wetlands is impacted by chronically elevated sulfate inputs, such as through mine discharges. The purpose of our study is to determine how sulfate discharges to wetlands from iron mining activities impact MeHg production. In this study, we compare spatial and temporal patterns in MeHg and associated geochemistry in two wetlands receiving contrasting loads of sulfate. Two orders of magnitude less sulfate in the un-impacted wetland create significant differences in acid-volatile sulfide and porewater sulfide; however, dissolved and solid-phase MeHg concentrations and methylation rate potentials (Kmeth) are statistically similar in both wetlands. Permitted mine pumping events flood the sulfate-impacted wetland with very high sulfate waters during the fall. In contrast to observations in sulfate-limited systems, this large input of sulfate to a chronically sulfate-impacted system led to significantly lower potential relative methylation rates, suggesting a predominance of demethylation processes over methylation processes during the sulfate loading. Overall, short-term measurements of methylation and demethylation potential are unrelated to gross measures of long-term MeHg accumulation, indicating a decoupling of short- and long-term process measurements and an overall disequilibrium in the systems. High sulfide accumulation, above ∼600-800 μg l(-1) sulfide, in the sulfate-impacted system lowers long-term MeHg accumulation, perhaps as a result of less bioavailable Hg-S complexes. Although continued research is required to determine how sulfate-limited freshwater wetlands might respond to new, large inputs of high-sulfate runoff from mining operations, chronically impacted wetlands do not appear to continually accumulate or produce MeHg at rates different from wetlands unimpacted by mining.
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Affiliation(s)
- Nathan W Johnson
- Department of Civil Engineering, University of Minnesota Duluth, USA.
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