1
|
Huang H, Mackereth RW, Mitchell CPJ. Impacts of forest harvesting on mercury concentrations and methylmercury production in boreal forest soils and stream sediment. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 341:122966. [PMID: 37981183 DOI: 10.1016/j.envpol.2023.122966] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 11/13/2023] [Accepted: 11/14/2023] [Indexed: 11/21/2023]
Abstract
Methylmercury (MeHg) is the most neurotoxic and bioaccumulative form of mercury (Hg) present in the terrestrial and aquatic food sources of boreal ecosystems, posing potential risks to wildlife and human health. Harvesting impacts on Hg methylation and MeHg concentrations in forest soils and stream sediment are not fully understood. In this study, a field investigation was carried out in 4 harvested and 2 unharvested boreal forest watersheds, before and after harvest, to better understand impacts on Hg methylation and MeHg concentration in soils and stream sediment, including their responses to different forest management practices. Changes in total Hg (THg) and MeHg concentrations, first-order potential rate constants for Hg methylation and MeHg demethylation (Kmeth and Kdemeth) as well as total carbon content and carbon-to-nitrogen ratio post-harvest in upland, wetland and riparian soils and stream sediment were assessed and compared. Increases in MeHg production were minimal in upland, wetland or riparian soils after harvest. Sediment in streams with minor buffer protection (∼3 m), greater fractions (>75%) of harvested watershed area and more road construction had significantly increased THg and MeHg concentrations, %-MeHg, Kmeth and total carbon content post-harvest. From these patterns, we infer that inputs of carbon and inorganic Hg into harvest-impacted stream sediment are likely sourced from the harvested upland areas and stimulate in situ MeHg production in stream sediment. These findings indicate the importance of stream sediment as potential MeHg pools in harvested forest watersheds. The findings also demonstrate that forest management practices aiming to mitigate organic matter and Hg inputs to streams can effectively alleviate harvesting impacts on Hg methylation and MeHg concentrations in stream sediment.
Collapse
Affiliation(s)
- Haiyong Huang
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - Robert W Mackereth
- Centre for Northern Forest Ecosystem Research, Ontario Ministry of Natural Resources and Forestry, Thunder Bay, ON, Canada
| | - Carl P J Mitchell
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, ON, Canada.
| |
Collapse
|
2
|
Baldwin AK, Janssen SE, Tate MT, Poulin BA, Yoder AM, Naymik J, Larsen C, Hoovestol C, Krabbenhoft DP. Mercury sources and budget for the Snake River above a hydroelectric reservoir complex. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 907:167961. [PMID: 37865255 DOI: 10.1016/j.scitotenv.2023.167961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/13/2023] [Accepted: 10/18/2023] [Indexed: 10/23/2023]
Abstract
Understanding sources of mercury (Hg) and methylmercury (MeHg) to a water body is critical for management but is often complicated by poorly characterized Hg inputs and in situ processes, such as inorganic Hg methylation. In this study, we determined inorganic Hg and MeHg concentrations and loads (filter-passing and particulate fractions) for a semi-arid 164-kilometer stretch of the Snake River above the Hells Canyon Complex, a Hg-impaired hydroelectric reservoir complex on the Idaho-Oregon border, and used water quality measurements and Hg stable isotope ratios to create a comprehensive Hg source budget for the river. Results show that whereas most of the streamflow to the study reach comes from the main branch of the Snake River (i.e., the upstream watershed), major tributaries within the study reach contribute a greater proportion of inorganic Hg and MeHg loads. Mercury stable-isotope analyses highlight that Hg within the tributaries is predominantly associated with geologic deposits and snowmelt sources, the latter reflecting wet deposition. Surprisingly, irrigation return drains contribute 40-50 % of particulate inorganic Hg loads despite being ≤4.3 % of the overall water budget. Together, tributaries and irrigation return drains account for 97-100 % of the inorganic Hg and streamflow to the study reach, but ~65 % of the MeHg, indicating in-stream and riparian methylation may be an important and previously unrecognized source of MeHg. Streamflow, total suspended solids, dissolved organic carbon, and agricultural land cover were found to be important controls on the mobilization and transport of different Hg species and fractions. This study represents the first fluvial budget for Hg in the Snake River that accounts for particulate and filter-passing Hg species from both major tributaries and irrigation return drains, and expands our understanding of Hg sources and methylation processes within semi-arid environments. This information is critical to inform management decisions related to elevated Hg burdens in biota.
Collapse
Affiliation(s)
- Austin K Baldwin
- U.S. Geological Survey, Idaho Water Science Center, United States of America.
| | - Sarah E Janssen
- U.S. Geological Survey, Upper Midwest Water Science Center, United States of America
| | - Michael T Tate
- U.S. Geological Survey, Upper Midwest Water Science Center, United States of America
| | - Brett A Poulin
- Department of Environmental Toxicology, University of California at Davis, United States of America
| | - Alysa M Yoder
- U.S. Geological Survey, Idaho Water Science Center, United States of America
| | | | | | | | - David P Krabbenhoft
- U.S. Geological Survey, Upper Midwest Water Science Center, United States of America
| |
Collapse
|
3
|
Hall LA, Woo I, Marvin-DiPasquale M, Takekawa JY, Krabbenhoft DP, Yee D, Grenier L, De La Cruz SEW. Linking Mesoscale Spatial Variation in Methylmercury Production to Bioaccumulation in Tidal Marsh Food Webs. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:19263-19273. [PMID: 37956992 DOI: 10.1021/acs.est.3c04907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
Differences in sediment biogeochemistry among tidal marsh features with different hydrological and geomorphological characteristics, including marsh interiors, marsh edges, first-order channels, and third-order channels, can result in spatial variation in MeHg production and availability. To better understand the link between MeHg production in sediments and bioaccumulation in primary and secondary consumer invertebrates and fish, we characterized mesoscale spatial variation in sediment biogeochemistry and MeHg concentrations of sediments, water, and consumer tissues among marsh features. Our results indicated that marsh interiors had biogeochemical conditions, including greater concentrations of organic matter and sulfate reduction rates, that resulted in greater MeHg concentrations in sediments and surface water particulates from marsh interiors compared to other features. Tissue MeHg concentrations of consumers also differed among features, with greater concentrations from marsh edges and interiors compared to channels. This spatial mismatch of MeHg concentrations in sediments and water compared to those in consumers may have resulted from differences in behavior and physiology among consumers that influenced the spatial scale over which MeHg was integrated into tissues. Our results highlight the importance of sampling across a suite of marsh features and considering the behavioral and physiological traits of sentinel taxa for contaminant monitoring studies.
Collapse
Affiliation(s)
- Laurie A Hall
- U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, NASA Research Park Bldg. 19, N. Akron Road, Moffett Field, California 94035, United States
| | - Isa Woo
- U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, NASA Research Park Bldg. 19, N. Akron Road, Moffett Field, California 94035, United States
| | - Mark Marvin-DiPasquale
- U.S. Geological Survey, Water Mission Area, Earth System Processes Division, 345 Middlefield Road, Menlo Park, California 94025, United States
| | - John Y Takekawa
- U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, NASA Research Park Bldg. 19, N. Akron Road, Moffett Field, California 94035, United States
| | - David P Krabbenhoft
- U.S. Geological Survey, Mercury Research Laboratory, 8505 Research Way, Middleton, Wisconsin 53562, United States
| | - Donald Yee
- San Francisco Estuary Institute, 4911 Central Avenue, Richmond, California 94804, United States
| | - Letitia Grenier
- San Francisco Estuary Institute, 4911 Central Avenue, Richmond, California 94804, United States
| | - Susan E W De La Cruz
- U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, NASA Research Park Bldg. 19, N. Akron Road, Moffett Field, California 94035, United States
| |
Collapse
|
4
|
Oliveira VH, Fonte BA, Costa F, Sousa AI, Henriques B, Pereira E, Dolbeth M, Díez S, Coelho JP. The effect of Zostera noltei recolonization on the sediment mercury vertical profiles of a recovering coastal lagoon. CHEMOSPHERE 2023; 345:140438. [PMID: 37852379 DOI: 10.1016/j.chemosphere.2023.140438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 09/07/2023] [Accepted: 10/12/2023] [Indexed: 10/20/2023]
Abstract
Mercury's extreme toxicity and persistence in the environment justifies a thorough evaluation of its dynamics in ecosystems. Aveiro Lagoon (Portugal) was for decades subject to mercury effluent discharges. A Nature-based Solution (NbS) involving Zostera noltei re-colonization is being tested as an active ecosystem restoration measure. To study the effect of Zostera noltei on the sediment contaminant biogeochemistry, seasonal (summer/winter) sediment, interstitial water and labile mercury vertical profiles were made in vegetated (Transplanted and Natural seagrass meadows) and non-vegetated sites (Bare-bottom area). While no significant differences (p > 0.05) were observed in the sedimentary phase, Zostera noltei presence reduced the reactive/labile mercury concentrations in the top sediment layers by up to 40% when compared to non-vegetated sediment, regardless of season. No differences were found between vegetated meadows, highlighting the fast recovery of the contaminant regulation ecosystem function provided by the plants after re-colonization and its potential for the rehabilitation of historically contaminated ecosystems.
Collapse
Affiliation(s)
- V H Oliveira
- ECOMARE - Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Estrada do Porto de Pesca Costeira, 3830-565, Gafanha da Nazaré, Portugal.
| | - B A Fonte
- ECOMARE - Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Estrada do Porto de Pesca Costeira, 3830-565, Gafanha da Nazaré, Portugal
| | - F Costa
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - A I Sousa
- ECOMARE - Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Estrada do Porto de Pesca Costeira, 3830-565, Gafanha da Nazaré, Portugal
| | - B Henriques
- LAQV-REQUIMTE- Associated Laboratory for Green Chemistry of the Network of Chemistry and Technology, Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal
| | - E Pereira
- LAQV-REQUIMTE- Associated Laboratory for Green Chemistry of the Network of Chemistry and Technology, Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal
| | - M Dolbeth
- CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, Novo Edifício Do Terminal de Cruzeiros Do Porto de Leixões, Avenida General Norton de Matos S/N, 4450-208, Matosinhos, Portugal
| | - S Díez
- Environmental Chemistry Department, Institute of Environmental Assessment and Water Research, IDAEA-CSIC, E-08034, Barcelona, Spain
| | - J P Coelho
- ECOMARE - Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Estrada do Porto de Pesca Costeira, 3830-565, Gafanha da Nazaré, Portugal
| |
Collapse
|
5
|
Hartfiel LM, Hoover NL, Hall SJ, Isenhart TM, Gomes CL, Soupir ML. Extreme low-flow conditions in a dual-chamber denitrification bioreactor contribute to pollution swapping with low landscape-scale impact. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 877:162837. [PMID: 36924958 DOI: 10.1016/j.scitotenv.2023.162837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/17/2023] [Accepted: 03/09/2023] [Indexed: 05/06/2023]
Abstract
Denitrification bioreactors are an effective edge-of-field conservation practice for nitrate (NO3) reduction from subsurface drainage. However, these systems may produce other pollutants and greenhouse gases during NO3 removal. Here a dual-chamber woodchip bioreactor system experiencing extreme low-flow conditions was monitored for its spatiotemporal NO3 and total organic carbon dynamics in the drainage water. Near complete removal of NO3 was observed in both bioreactor chambers in the first two years of monitoring (2019-2020) and in the third year of monitoring in chamber A, with significant (p < 0.01) reduction of the NO3-N each year in both chambers with 8.6-11.4 mg NO3-N L-1 removed on average. Based on the NO3 removal observed, spatial monitoring of sulfate (SO4), dissolved methane (CH4), and dissolved nitrous oxide (N2O) gases was added in the third year of monitoring (2021). In 2021, chambers A and B had median hydraulic residence times (HRTs) of 64 h and 39 h, respectively, due to varying elevations of the chambers, with drought conditions making the differences more pronounced. In 2021, significant production of dissolved CH4 was observed at rates of 0.54 g CH4-C m-3 d-1 and 0.07 g CH4-C m-3 d-1 in chambers A and B, respectively. In chamber A, significant removal (p < 0.01) of SO4 (0.23 g SO4 m-3 d-1) and dissolved N2O (0.21 mg N2O-N m-2 d-1) were observed, whereas chamber B produced N2O (0.36 mg N2O-N m-2 d-1). Considering the carbon dioxide equivalents (CO2e) on an annual basis, chamber A had loads (~12,000 kg CO2e ha-1 y-1) greater than comparable poorly drained agricultural soils; however, the landscape-scale impact was small (<1 % change in CO2e) when expressed over the drainage area treated by the bioreactor. Under low-flow conditions, pollution swapping in woodchip bioreactors can be reduced at HRTs <50 h and NO3 concentrations >2 mg N L-1.
Collapse
Affiliation(s)
- Lindsey M Hartfiel
- UW Discovery Farms, University of Wisconsin-Madison, Division of Extension, Madison, WI, United States.
| | - Natasha L Hoover
- Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA, United States
| | - Steven J Hall
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, United States
| | - Thomas M Isenhart
- Department of Natural Resource Ecology and Management, Iowa State University, Ames, IA, United States
| | - Carmen L Gomes
- Department of Mechanical Engineering, Iowa State University, Ames, IA, United States
| | - Michelle L Soupir
- Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA, United States
| |
Collapse
|
6
|
Wang J, Chen L, Song Y, Li Y, Liu G, Yin Y, Cai Y. Adsorption and environmental behavior of mercury on the sediment from the Yellow Sea of China. JOURNAL OF HAZARDOUS MATERIALS 2023; 443:130333. [PMID: 36372026 DOI: 10.1016/j.jhazmat.2022.130333] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 10/16/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
The Yellow Sea (YS) of China is facing severe mercury (Hg) pollution problems while the concentration of Hg in the sediment is relatively low compared to its high discharge intensity, whose mechanisms are still unclear. Here, we performed batch experiments to investigate the Hg adsorption capacity of the YS sediments. Freundlich isothermal adsorption simulation results showed that the parameters KF (adsorption capacity constant) of the sediments were varied from 3.33 to 2.88 × 104. Correlation analysis of KF against the physicochemical properties and sequential extraction revealed that organic matter (OM) and particle size influenced the KF for Hg. In addition, the calculated smaller Kd (distribution coefficient) values in the YS compared to other coastal seas indicate that at the sediment-water interface, Hg tends to be more present in porewater. There is also a significant positive correlation between KF and Kd. We conclude that the low OM content of YS sediments is one of the main reasons for their weak adsorption capacity. These findings provide a scientific basis for the phenomenon that Hg entering the YS undergoes environmental behaviors to maintain low concentrations in the sediment, deepen the understanding of Hg cycling in the YS and improve long-term risk prediction capacity for Hg in marine environments.
Collapse
Affiliation(s)
- Jing Wang
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Lufeng Chen
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Yue Song
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China.
| | - Yanbin Li
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, China.
| | - Guangliang Liu
- Department of Chemistry & Biochemistry, Florida International University, Miami, FL 33199, United States
| | - Yongguang Yin
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yong Cai
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China; Department of Chemistry & Biochemistry, Florida International University, Miami, FL 33199, United States
| |
Collapse
|
7
|
Swinton MW, Myer PK, Schaller MF, Pettitt EA, Farrell JL, Nierzwicki-Bauer SA. Stable carbon and nitrogen isotopes explain methylmercury concentrations in stream food webs of Lake George, New York (USA). ECOTOXICOLOGY (LONDON, ENGLAND) 2022; 31:808-821. [PMID: 35482143 DOI: 10.1007/s10646-022-02548-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/12/2022] [Indexed: 06/14/2023]
Abstract
Mercury has been studied extensively in lakes due to health risks associated with the consumption of contaminated fish, while stream ecosystems have received less attention. To better understand mercury bioavailability in the lower food web of streams, we collected macroinvertebrates (predators and detritivore) along with autochthonous (epilithic algae) and allochthonous (leaf litter) basal resources in eight streams entering Lake George. Samples were analyzed for methylmercury (MeHg), total mercury, and carbon and nitrogen isotopes (δ13C & δ15N) to determine how mercury concentrations in basal resources, biomagnification rates, and environmental factors (watershed characteristics and water chemistry) effected MeHg concentrations in predatory macroinvertebrates. While biomagnification rates, calculated as trophic magnification slope, explained between 68% and 98% of MeHg variability within a stream food web, the range was small (0.310-0.387) resulting in the biotic components following a consistent pattern of increasing MeHg among streams. The stream order was negatively related to basin slope for all biotic components and explained 70% of MeHg variability in predatory macroinvertebrates. Methylmercury concentrations were significantly and negatively related to δ13C in predators, epilithic algae, and leaf litter. We believe the biofilms on leaf litter utilized bacterial-respired carbon dioxide decreasing δ13C (<-28‰) and increasing MeHg while epilithic algal δ13C increased due to enhanced primary production resulting in biodilution of MeHg. Methylmercury in basal resources responded to δ13C similarly but through different processes. Our findings show shallow slopes elevate MeHg in basal resources and explain most of the predator MeHg variation among streams with little influence of biomagnification rates.
Collapse
Affiliation(s)
- M W Swinton
- Darrin Fresh Water Institute, Rensselaer Polytechnic Institute, 5060 Lake Shore Drive, Bolton Landing, NY, 12814, USA.
| | - P K Myer
- Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY, 12180, USA
| | - M F Schaller
- Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY, 12180, USA
| | - E A Pettitt
- Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY, 12180, USA
| | - J L Farrell
- Darrin Fresh Water Institute, Rensselaer Polytechnic Institute, 5060 Lake Shore Drive, Bolton Landing, NY, 12814, USA
- Department of Biological Sciences, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY, 12180, USA
| | - S A Nierzwicki-Bauer
- Darrin Fresh Water Institute, Rensselaer Polytechnic Institute, 5060 Lake Shore Drive, Bolton Landing, NY, 12814, USA
- Department of Biological Sciences, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY, 12180, USA
| |
Collapse
|
8
|
Huang S, Zhao Y, Lv S, Wang W, Wang W, Zhang Y, Huo Y, Sun X, Chen Y. Distribution of mercury isotope signatures in Yundang Lagoon, Xiamen, China, after long-term interventions. CHEMOSPHERE 2021; 272:129716. [PMID: 33601205 DOI: 10.1016/j.chemosphere.2021.129716] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/14/2021] [Accepted: 01/17/2021] [Indexed: 05/24/2023]
Abstract
Isotope signatures of mercury (Hg) were determined for Hg fractions in seawater, sediments, porewaters, core sediments and fish from the Yundang Lagoon, Xiamen, China. Sequential extraction was used to extract Hg fractions in sediments and the purge-trap method was used to preconcentrate Hg in seawater. A large variation in mass dependent fractionation (δ202Hg: -2.50‰ to -0.36‰) was observed in the lagoon. Seawater and fish samples showed positive mass-independent fractionation (Δ199Hg: -0.06‰-0.45‰), while most of sediment and porewater samples displayed insignificant mass-independent fractionation (Δ199Hg: -0.10‰-0.07‰). Ancillary parameters (total organic carbon, sulfide, pH, Eh, water content and grain size) were also measured in the sediments to investigate correlations with Hg isotopes. Three sources (domestic sewage, sediments and atmospheric deposition) were identified as the main sources of Hg in the lagoon seawater. Photochemical reaction was the main process causing isotope fractionation in seawater. Through Hg partitioning and deposition, light isotopes were enriched from dissolved Hg to particulate Hg, then to sediments, and then to porewaters. Finally, Hg isotope signatures were used to identify the Hg sources and fractionation processes in core sediments from different depths. Our results demonstrate that Hg isotopes are powerful tools for tracing Hg sources and arriving at a better understanding of Hg biogeochemical cycling in the lagoon after long-term interventions.
Collapse
Affiliation(s)
- Shuyuan Huang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, China
| | - Yuhan Zhao
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
| | - Supeng Lv
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Weiguo Wang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Weili Wang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Yuanbiao Zhang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China.
| | - Yunlong Huo
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Xiuwu Sun
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Yaojin Chen
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, China
| |
Collapse
|
9
|
Xiang Y, Liu G, Yin Y, Cai Y. Periphyton as an important source of methylmercury in Everglades water and food web. JOURNAL OF HAZARDOUS MATERIALS 2021; 410:124551. [PMID: 33223320 DOI: 10.1016/j.jhazmat.2020.124551] [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: 06/22/2020] [Revised: 09/23/2020] [Accepted: 11/10/2020] [Indexed: 06/11/2023]
Abstract
Periphyton is ubiquitous in Florida Everglades and has a profound effect on mercury (Hg) cycling. Enhanced methylmercury (MeHg) production in periphyton has been well documented, but the re-distribution of MeHg from periphyton remains unknown. In this study, periphyton, sediments, surface water, periphyton overlying water, and periphyton porewater were collected from Everglades for analyzing the distribution of MeHg and total Hg (THg). Results showed that there were no significant differences in THg and MeHg in different types of periphyton, but they all displayed higher MeHg levels than sediments. MeHg distribution coefficients (logkd) in periphyton were lower than in sediments, suggesting that periphyton MeHg could be more labile entering aquatic cycling and bioaccumulation. In water, the more the distance of water samples taken from periphyton, the lower the MeHg and dissolved organic carbon concentrations were detected. In extracellular polymeric substances of periphyton, MeHg in colloidal fractions was significantly higher than that in capsular fractions. It was estimated that approximately 10% (or 1.35 kg) of periphyton MeHg were passed on to mosquitofish entering the food web during wet season, contributing 73% of total Hg stocked in mosquitofish. These results revealed the importance of periphyton on water MeHg distribution and MeHg bioaccumulation in Everglades.
Collapse
Affiliation(s)
- Yuping Xiang
- Department of Chemistry & Biochemistry and Southeast Environmental Research Center, Florida International University, 11200 SW 8th ST, Miami, FL 33199, USA; Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Guangliang Liu
- Department of Chemistry & Biochemistry and Southeast Environmental Research Center, Florida International University, 11200 SW 8th ST, Miami, FL 33199, USA
| | - Yongguang Yin
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yong Cai
- Department of Chemistry & Biochemistry and Southeast Environmental Research Center, Florida International University, 11200 SW 8th ST, Miami, FL 33199, USA; Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| |
Collapse
|
10
|
Eckley CS, Luxton TP, Stanfield B, Baldwin A, Holloway J, McKernan J, Johnson MG. Effect of organic matter concentration and characteristics on mercury mobilization and methylmercury production at an abandoned mine site. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 271:116369. [PMID: 33401216 PMCID: PMC7903515 DOI: 10.1016/j.envpol.2020.116369] [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: 07/03/2020] [Revised: 12/16/2020] [Accepted: 12/20/2020] [Indexed: 05/05/2023]
Abstract
Thousands of abandoned mines throughout the western region of North America contain elevated total-mercury (THg) concentrations. Mercury is mobilized from these sites primarily due to erosion of particulate-bound Hg (THg-P). Organic matter-based soil amendments can promote vegetation growth on mine tailings, reducing erosion and subsequent loading of THg-P into downstream waterbodies. However, the introduction of a labile carbon source may stimulate microbial activity that can produce methylmercury (MeHg)-the more toxic and bioaccumulative form of Hg. Our objectives were to investigate how additions of different organic matter substrates impact Hg mobilization and methylation using a combination of field observations and controlled experiments. Field measurements of water, sediment, and porewater were collected downstream of the site and multi-year monitoring (and load calculations) were conducted at a downstream gaging station. MeHg production was assessed using stable isotope methylation assays and mesocosm experiments that were conducted using different types of organic carbon soil amendments mixed with materials from the mine site. The results showed that >80% of the THg mobilized from the mine was bound to particles and that >90% of the annual Hg loading occurred during the period of elevated discharge during spring snowmelt. Methylation rates varied between different types of soil amendments and were correlated with the components of excitation emission matrices (EEMs) associated with humic acid fractions of organic matter. The mesocosm experiments showed that under anoxic conditions carbon amendments to tailings could significantly increase porewater MeHg concentrations (up to 13 ± 3 ng/L). In addition, the carbon amendments significantly increased THg partitioning into porewater. Overall, these results indicate that soil amendment applications to reduce surface erosion at abandoned mine sites could be effective at reducing particulate Hg mobilization to downstream waterbodies; however, some types of carbon amendments can significantly increase Hg methylation as well as increase the mobilization of dissolved THg from the site.
Collapse
Affiliation(s)
- Chris S Eckley
- U.S. Environmental Protection Agency, Region-10, Seattle, WA, USA.
| | - Todd P Luxton
- U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, USA
| | - Brooks Stanfield
- U.S. Environmental Protection Agency, Region-10, Seattle, WA, USA
| | - Austin Baldwin
- U.S. Geological Survey, Idaho Water Science Center, Boise, ID, USA
| | - JoAnn Holloway
- U.S. Geological Survey, Geology, Geophysics, and Geochemistry Science Center, Denver, CO, USA
| | - John McKernan
- U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, USA
| | - Mark G Johnson
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Pacific Ecological Systems Division, Corvallis, OR, USA
| |
Collapse
|
11
|
Ku P, Tsui MTK, Liu S, Corson KB, Williams AS, Monteverde MR, Woerndle GE, Hershey AE, Rublee PA. Examination of mercury contamination from a recent coal ash spill into the Dan River, North Carolina, United States. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 208:111469. [PMID: 33091769 DOI: 10.1016/j.ecoenv.2020.111469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/05/2020] [Accepted: 10/06/2020] [Indexed: 06/11/2023]
Abstract
Coal ash spills occasionally occur due to the accidental failure of surface impoundments, and toxic metal-laden ash can pose a serious health threat to adjacent aquatic ecosystems. Here, we performed an investigation into longitudinal variations of mercury (Hg) contamination in the Dan River (North Carolina, United States) about 17 and 29 months after a February 2014 coal ash spill incident, in which the reported Hg concentrations in the spilled coal ash (210 ng/g) were 1-2 orders of magnitude higher than the river sediments (2-61 ng/g). We examined total Hg (THg) and methyl Hg (MeHg) in sediments from 0 to 65 km downstream of the spill, and found that most of the variations of THg and MeHg in surface sediments (0-16 cm) could be well accounted by the organic matter content and appeared to be not contaminated by Hg derived from coal ash. In examining MeHg bioaccumulation in invertebrates (aquatic and riparian) and fish in the Dan River and fish in a reservoir downstream of Dan River, we found no evidence of elevated MeHg bioaccumulation due to the 2014 coal ash spill. Thus, we concluded that Hg contamination from the coal ash spill is largely absent in the Dan River for both surface sediments and biota within the first three years of spill (until 2017), even though the majority of coal ash may be buried deeper in the sediment in the river channel and/or the downstream reservoir. Alternatively, the Hg associated with the coal ash is largely not bioavailable for extensive microbial Hg methylation. The findings provide useful insights into remediation strategies for this incident and other coal ash spills.
Collapse
Affiliation(s)
- Peijia Ku
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | - Martin Tsz-Ki Tsui
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
| | - Songnian Liu
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | - Kimber B Corson
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | - Ashley S Williams
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | - Matthew R Monteverde
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | - Glenn E Woerndle
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | - Anne E Hershey
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | - Parke A Rublee
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| |
Collapse
|
12
|
Swinton MW, Nierzwicki-Bauer SA. Mercury increase in Lake Champlain fish: links to fishery dynamics and extreme climatic events. ECOTOXICOLOGY (LONDON, ENGLAND) 2020; 29:1750-1761. [PMID: 31893335 DOI: 10.1007/s10646-019-02148-5] [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: 12/05/2019] [Indexed: 06/10/2023]
Abstract
Mercury concentrations in Lake Champlain fish increased (2011-2017) for the first time in more than two decades. The increase, however, was not consistent among species or throughout the lake. Mercury concentrations in smallmouth bass and yellow perch from the three Main Lake segments increased significantly while concentrations in the eastern portions of the lake (Northeast Arm and Malletts Bay) remained unchanged or decreased; mercury concentrations in white perch remained unchanged. Factors examined to explain the increase included: atmospheric deposition, lake temperature, chlorophyll-a, fishery dynamics, lake flooding and loading of total suspended solids (TSS). This paper examines how each factor has changed between study periods and the spatial variability associated with the change. We hypothesize fishery dynamics, flooding and TSS loading may be partially responsible for the increase in fish mercury. Both growth efficiency and biomass of fish suggest mercury concentrations would increase in the Main Lake segments and decrease in the eastern portion of the lake. Additionally, two extreme climate events in 2011 resulted in extensive flooding and a four-fold increase in annual TSS loading, both potentially increasing biotic mercury with the impact varying spatially throughout the lake. Changes to the fishery and disturbance caused by extreme climatic events have increased biotic mercury and the processes responsible need further study to identify possible future scenarios in order to better protect human and wildlife health.
Collapse
Affiliation(s)
- Mark W Swinton
- Darrin Fresh Water Institute, Rensselaer Polytechnic Institute, 5060 Lake Shore Drive, Bolton Landing, NY, 12814, USA.
| | - Sandra A Nierzwicki-Bauer
- Darrin Fresh Water Institute, Rensselaer Polytechnic Institute, 5060 Lake Shore Drive, Bolton Landing, NY, 12814, USA
- Department of Biological Sciences, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY, 12180, USA
| |
Collapse
|
13
|
Shanley JB, Marvin-DiPasquale M, Lane O, Arendt W, Hall S, McDowell WH. Resolving a paradox-high mercury deposition, but low bioaccumulation in northeastern Puerto Rico. ECOTOXICOLOGY (LONDON, ENGLAND) 2020; 29:1207-1220. [PMID: 31643013 DOI: 10.1007/s10646-019-02108-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: 09/05/2019] [Indexed: 06/10/2023]
Abstract
At a "clean air" trade winds site in northeastern Puerto Rico, we found an apparent paradox: atmospheric total mercury (THg) deposition was highest of any site in the USA Mercury Deposition Network, but assimilation into the local food web was quite low. Avian blood THg concentrations (n = 31, from eight species in five foraging guilds) ranged widely from 0.2 to 32 ng g-1 (median of 4.3 ng g-1). Within this population, THg was significantly greater at a low-elevation site near a wetland compared to an upland montane site, even when the comparison was limited to a single species. Overall, however, THg concentrations were approximately an order of magnitude lower than comparable populations in the continental U.S. In surface soil and sediment, potential rates of demethylation were 3 to 9-fold greater than those for Hg(II)-methylation (based on six radiotracer amendment incubations), but rates of change of ambient MeHg pools showed a slight net positive Hg(II)-methylation. Thus, the resolution of the paradox is that MeHg degradation approximately keeps pace with MeHg production in this landscape. Further, any net production of MeHg is subject to frequent flushing by high rainfall on chronically wet soils. The interplay of these microbial processes and hydrology appears to shield the local food web from adverse effects of high atmospheric mercury loading. This scenario may play out in other humid tropical ecosystems as well, but it is difficult to evaluate because coordinated studies of Hg deposition, methylation, and trophic uptake have not been conducted at other tropical sites.
Collapse
Affiliation(s)
- James B Shanley
- U.S. Geological Survey, P.O. Box 628, Montpelier, VT, 05601, USA.
| | | | - Oksana Lane
- Biodiversity Research Institute, Portland, ME, USA
| | - Wayne Arendt
- USFS, International Institute of Tropical Forestry, Luquillo, PR, USA
| | - Steven Hall
- Department of Ecology and Evolutionary Biology, Iowa State University, Ames, IA, USA
| | - William H McDowell
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USA
| |
Collapse
|
14
|
Bishop K, Shanley JB, Riscassi A, de Wit HA, Eklöf K, Meng B, Mitchell C, Osterwalder S, Schuster PF, Webster J, Zhu W. Recent advances in understanding and measurement of mercury in the environment: Terrestrial Hg cycling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 721:137647. [PMID: 32197286 DOI: 10.1016/j.scitotenv.2020.137647] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 02/23/2020] [Accepted: 02/28/2020] [Indexed: 06/10/2023]
Abstract
This review documents recent advances in terrestrial mercury cycling. Terrestrial mercury (Hg) research has matured in some areas, and is developing rapidly in others. We summarize the state of the science circa 2010 as a starting point, and then present the advances during the last decade in three areas: land use, sulfate deposition, and climate change. The advances are presented in the framework of three Hg "gateways" to the terrestrial environment: inputs from the atmosphere, uptake in food, and runoff with surface water. Among the most notable advances: These and other advances reported here are of value in evaluating the effectiveness of the Minamata Convention on reducing environmental Hg exposure to humans and wildlife.
Collapse
Affiliation(s)
- Kevin Bishop
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Box 7050, 75007 Uppsala, Sweden.
| | | | - Ami Riscassi
- Department of Environmental Sciences, University of Virginia, P.O. Box 400123, Charlottesville, VA 22904-4123, USA.
| | - Heleen A de Wit
- Norwegian Institute for Water Research, Gaustadalléen 21, NO-0349, Norway.
| | - Karin Eklöf
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Box 7050, 75007 Uppsala, Sweden.
| | - Bo Meng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China.
| | - Carl Mitchell
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada.
| | - Stefan Osterwalder
- Institut des Géosciences de l'Environnement, Université Grenoble Alpes, CNRS, IRD, Grenoble 18 INP, 38000 Grenoble, France.
| | - Paul F Schuster
- U.S. Geological Survey, 3215 Marine Street, Suite E-127, Boulder, CO 80303-1066, USA.
| | - Jackson Webster
- Department of Civil Engineering, California State University, 400 W. 1st Street, 21 95929-0930 Chico, CA, USA.
| | - Wei Zhu
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, 90183 Umeå, Sweden.
| |
Collapse
|
15
|
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.
Collapse
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.
| |
Collapse
|
16
|
Zhao L, Meng B, Feng X. Mercury methylation in rice paddy and accumulation in rice plant: A review. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 195:110462. [PMID: 32179234 DOI: 10.1016/j.ecoenv.2020.110462] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 03/07/2020] [Accepted: 03/08/2020] [Indexed: 06/10/2023]
Abstract
The bioavailability and toxicity of mercury (Hg) are dependent on its chemical speciation, in which methylmercury (MeHg) is the most toxic compound. Inorganic Hg can be transformed into MeHg in anaerobic conditions. Subsequent accumulation and biomagnification in the food chain pose a potential threat to human health. Previous studies have confirmed that paddy soil is an important site for MeHg production, and rice fields are an important source of MeHg in terrestrial ecosystems. Rice (Oryza sativa L.) is recently confirmed as a potential bioaccumulator plant of MeHg. Understanding the behaviour of Hg in rice paddies is important, particularly the mechanisms involved in Hg sources, uptake, toxicity, detoxification, and accumulation in crops. This review highlights the issue of MeHg-contaminated rice, and presents the current understanding of the Hg cycling in the rice paddy ecosystem, including the mechanism and processes of Hg species accumulation in rice plants and Hg methylation/demethylation processes in rice paddies and the primary controlling factors. The review also identified various research gaps in previous studies and proposes future research objectives to reduce the impact of Hg-contamination in rice crops.
Collapse
Affiliation(s)
- Lei Zhao
- School of Management Science, Guizhou University of Finance and Economics, Guiyang, 550025, PR China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, PR China
| | - Bo Meng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, PR China.
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, PR China.
| |
Collapse
|
17
|
Tsui MTK, Blum JD, Kwon SY. Review of stable mercury isotopes in ecology and biogeochemistry. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 716:135386. [PMID: 31839301 DOI: 10.1016/j.scitotenv.2019.135386] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/21/2019] [Accepted: 11/04/2019] [Indexed: 06/10/2023]
Abstract
Due to the advent of cold vapor-multicollector-inductively coupled plasma mass spectrometry (CV-MC-ICP-MS) in the past two decades, many research groups studying mercury (Hg) biogeochemistry have integrated stable Hg isotopes into their research. Currently, >200 studies using this technique have been published and this has greatly enhanced our understanding of the Hg biogeochemical cycle beyond what Hg concentration and speciation analyses alone can provide. These studies are largely divided into two groups: (i) controlled experiments investigating fractionation of Hg isotopes and refining tools of isotopic analyses, and (ii) studies of natural variations of Hg isotopes. It is now known that Hg isotopes undergo both mass dependent fractionation (MDF; reported as the ratio of mass 202Hg to 198Hg) and mass independent fractionation (MIF), with MIF occurring at odd masses (199Hg, 201Hg) to a larger magnitude and at even masses (200Hg, 204Hg) to a much smaller magnitude. The two types of MIF are controlled by different photochemical processes. The range of isotopic variations of MDF, odd-MIF, and even-MIF are now well documented in a diverse set of environmental samples, and researchers are continuing to explore how the field of Hg isotope biogeochemistry can be further developed and taken to the next level of understanding. One application that has received considerable attention is the use of Hg isotopes to examine the environmental controls on the production and degradation of methylmercury (MeHg), the most toxic and bioaccumulative form of Hg. Since MeHg is efficiently assimilated and biomagnified along food chains, MeHg has the potential to be a robust ecological tracer. In this review, we give an updated overview of the field of Hg isotopes and focus on how Hg isotopes of MeHg can be used to address fundamental ecological questions, including energy transfer across ecosystem interfaces and as a tracer for animal movements.
Collapse
Affiliation(s)
- Martin Tsz-Ki Tsui
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
| | - Joel D Blum
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sae Yun Kwon
- Division of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang 37673, South Korea
| |
Collapse
|
18
|
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.
Collapse
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.
| |
Collapse
|
19
|
Sanders JP, McBurney A, Gilmour CC, Schwartz GE, Washburn S, Kane Driscoll SB, Brown SS, Ghosh U. Development of a Novel Equilibrium Passive Sampling Device for Methylmercury in Sediment and Soil Porewaters. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2020; 39:323-334. [PMID: 31692059 PMCID: PMC9188764 DOI: 10.1002/etc.4631] [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: 07/07/2019] [Revised: 10/25/2019] [Accepted: 10/30/2019] [Indexed: 06/10/2023]
Abstract
We explored the concept of equilibrium passive sampling for methylmercury (MeHg) using the strategy developed for hydrophobic organic chemicals. Passive sampling should allow prediction of the concentration of the chemically labile fraction of MeHg in sediment porewaters based on equilibrium partitioning into the sampler, without modeling diffusion rates through the sampler material. Our goals were to identify sampler materials with the potential to mimic MeHg partitioning into animals and sediments and provide reversible sorption in a time frame appropriate for in situ samplers. Candidate materials tested included a range of polymers embedded with suitable sorbents for MeHg. The most promising were activated carbon (AC) embedded in agarose, thiol-self-assembled monolayers on mesoporous supports embedded in agarose, and cysteine-functionalized polyethylene terephthalate, which yielded log sampler-water partition coefficients of 2.8 to 5 for MeHgOH and MeHg complexed with dissolved organic matter (Suwannee River humic acid). Sampler equilibration time in sediments was approximately 1 to 2 wk. Investigation of the MeHg accumulation mechanism by AC embedded in agarose suggested that sampling was kinetically influenced by MeHg interactions with AC particles and not limited by diffusion through the gel for this material. Also, AC exhibited relatively rapid desorption of Hg and MeHg, indicating that this sorbent is capable of reversible, equilibrium measurements. In sediment:water microcosms, porewater concentrations made with isotherm-calibrated passive samplers agreed within a factor of 2 (unamended sediment) or 4 (AC-amended sediment) with directly measured concentrations. The present study demonstrates a potential new approach to passive sampling of MeHg. Environ Toxicol Chem 2020;39:323-334. © 2019 SETAC.
Collapse
Affiliation(s)
- James P Sanders
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Alyssa McBurney
- Smithsonian Environmental Research Center, Edgewater, Maryland, USA
| | | | - Grace E Schwartz
- Smithsonian Environmental Research Center, Edgewater, Maryland, USA
| | - Spencer Washburn
- Smithsonian Environmental Research Center, Edgewater, Maryland, USA
| | | | | | - Upal Ghosh
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, Maryland, USA
| |
Collapse
|
20
|
Hall LA, Woo I, Marvin-DiPasquale M, Tsao DC, Krabbenhoft DP, Takekawa JY, De La Cruz SEW. Disentangling the effects of habitat biogeochemistry, food web structure, and diet composition on mercury bioaccumulation in a wetland bird. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 256:113280. [PMID: 31718826 DOI: 10.1016/j.envpol.2019.113280] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/29/2019] [Accepted: 09/18/2019] [Indexed: 06/10/2023]
Abstract
Methylmercury (MeHg) is a globally pervasive contaminant with known toxicity to humans and wildlife. Several sources of variation can lead to spatial differences in MeHg bioaccumulation within a species including: biogeochemical processes that influence MeHg production and availability within an organism's home range; trophic positions of consumers and MeHg biomagnification efficiency in food webs; and individual prey preferences that influence diet composition. To better understand spatial variation in MeHg bioaccumulation within a species, we evaluated the effects of habitat biogeochemistry, food web structure, and diet composition in the wetland-obligate California black rail (Laterallus jamaicensis coturniculus) at three wetlands along the Petaluma River in northern San Francisco Bay, California, USA. The concentration of MeHg in sediments differed significantly among wetlands. We identified three sediment and porewater measurements that contributed significantly to a discriminant function explaining differences in habitat biogeochemistry among wetlands: the porewater concentration of ferrous iron, the percent organic matter, and the sediment MeHg concentration. Food web structure and biomagnification efficiency were similar among wetlands, with trophic magnification factors for MeHg ranging from 1.84 to 2.59. In addition, regurgitation samples indicated that black rails were dietary generalists with similar diets among wetlands (percent similarity indices > 70%). Given the similarities in diet composition, food web structure, and MeHg biomagnification efficiency among wetlands, we concluded that variation in habitat biogeochemistry and associated sediment MeHg production was the primary driver of differences in MeHg concentrations among black rails from different wetlands.
Collapse
Affiliation(s)
- Laurie A Hall
- U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, PO Box 158, Moffett Field, CA 94035, USA.
| | - Isa Woo
- U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, PO Box 158, Moffett Field, CA 94035, USA
| | - Mark Marvin-DiPasquale
- U.S. Geological Survey, Biogeochemistry Laboratory, 345 Middlefield Road, Menlo Park, CA 94025, USA
| | - Danika C Tsao
- U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, PO Box 158, Moffett Field, CA 94035, USA
| | - David P Krabbenhoft
- U.S. Geological Survey, Mercury Research Laboratory, 8505 Research Way, Middleton, WI 53562, USA
| | - John Y Takekawa
- U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, PO Box 158, Moffett Field, CA 94035, USA
| | - Susan E W De La Cruz
- U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, PO Box 158, Moffett Field, CA 94035, USA
| |
Collapse
|
21
|
Chen CF, Ju YR, Chen CW, Dong CD. The distribution of methylmercury in estuary and harbor sediments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 691:55-63. [PMID: 31319258 DOI: 10.1016/j.scitotenv.2019.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/24/2019] [Accepted: 07/01/2019] [Indexed: 06/10/2023]
Abstract
Methylmercury (MeHg) presents high toxicity to humans and can be accumulated to organisms via the food chains. In aquatic environments, MeHg is mainly formed by microorganism using the bioavailable inorganic mercury in sediment. In this study, a total of 120 surface sediments from 20 sites in the Kaohsiung Harbor were collected quarterly in the period from July 2016 to October 2017 and analyzed for total mercury (THg), bioavailable inorganic mercury (BIHg), MeHg, and several geochemical parameters. The concentrations of THg, BIHg, and MeHg in sediment were 455-5108, 7.0-1021, and 0.84-24.1 μg/kg dw, respectively. Results indicated that the percentage of MeHg to THg (MeHg ratio) in most sediment (85%) is <1.2%. Correlation analysis showed that MeHg in sediment was mainly controlled by BIHg (r = 0.759, p < 0.01), while the concentration of BIHg in sediment was mainly related to TOC (r = 0. 480, p < 0.01) and THg (r = 0.435, p < 0.01). The relationship between total bioavailable inorganic mercury (containing BIHg and the bioavailable inorganic mercury used in the synthesis of MeHg) and MeHg concentration in the sediments that collected from the estuary, harbor channel, and the entrance was established by a Michaelis-Menten model to predict the maximum value of MeHg. The efficiency of Hg methylation in the sediments of Kaohsiung Harbor is significantly affected by the total bioavailable inorganic mercury and the related environmental factors. In addition, changes in environmental conditions caused by local seasonality should also be an important factor to consider when assessing the efficiency of Hg methylation.
Collapse
Affiliation(s)
- Chih-Feng Chen
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 81157, Taiwan
| | - Yun-Ru Ju
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 81157, Taiwan
| | - Chiu-Wen Chen
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 81157, Taiwan.
| | - Cheng-Di Dong
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 81157, Taiwan.
| |
Collapse
|
22
|
Masoner JR, Kolpin DW, Cozzarelli IM, Barber LB, Burden DS, Foreman WT, Forshay KJ, Furlong ET, Groves JF, Hladik ML, Hopton ME, Jaeschke JB, Keefe SH, Krabbenhoft DP, Lowrance R, Romanok KM, Rus DL, Selbig WR, Williams BH, Bradley PM. Urban Stormwater: An Overlooked Pathway of Extensive Mixed Contaminants to Surface and Groundwaters in the United States. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:10070-10081. [PMID: 31432661 PMCID: PMC7370854 DOI: 10.1021/acs.est.9b02867] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Increasing global reliance on stormwater control measures to reduce discharge to surface water, increase groundwater recharge, and minimize contaminant delivery to receiving waterbodies necessitates improved understanding of stormwater-contaminant profiles. A multiagency study of organic and inorganic chemicals in urban stormwater from 50 runoff events at 21 sites across the United States demonstrated that stormwater transports substantial mixtures of polycyclic aromatic hydrocarbons, bioactive contaminants (pesticides and pharmaceuticals), and other organic chemicals known or suspected to pose environmental health concern. Numerous organic-chemical detections per site (median number of chemicals detected = 73), individual concentrations exceeding 10 000 ng/L, and cumulative concentrations up to 263 000 ng/L suggested concern for potential environmental effects during runoff events. Organic concentrations, loads, and yields were positively correlated with impervious surfaces and highly developed urban catchments. Episodic storm-event organic concentrations and loads were comparable to and often exceeded those of daily wastewater plant discharges. Inorganic chemical concentrations were generally dilute in concentration and did not exceed chronic aquatic life criteria. Methylmercury was measured in 90% of samples with concentrations that ranged from 0.05 to 1.0 ng/L.
Collapse
Affiliation(s)
- Jason R. Masoner
- U.S. Geological Survey, Oklahoma City, Oklahoma 73116, United States
| | - Dana W. Kolpin
- U.S. Geological Survey, Iowa City, Iowa 52240, United States
| | | | - Larry B. Barber
- U.S. Geological Survey, Boulder, Colorado 80303, United States
| | - David S. Burden
- U.S. Environmental Protection Agency, Ada, Oklahoma 74820, United States
| | | | - Kenneth J. Forshay
- U.S. Environmental Protection Agency, Ada, Oklahoma 74820, United States
| | | | - Justin F. Groves
- U.S. Environmental Protection Agency, Ada, Oklahoma 74820, United States
| | | | - Matthew E. Hopton
- U.S. Environmental Protection Agency, Cincinnati, Ohio 45268, United States
| | | | | | | | - Richard Lowrance
- U.S. Environmental Protection Agency, Ada, Oklahoma 74820, United States
| | | | - David L. Rus
- U.S. Geological Survey, Lincoln, Nebraska 68512, United States
| | | | | | - Paul M. Bradley
- U.S. Geological Survey, Columbia, South Carolina 29210, United States
| |
Collapse
|
23
|
Rivera NA, Bippus PM, Hsu-Kim H. Relative Reactivity and Bioavailability of Mercury Sorbed to or Coprecipitated with Aged Iron Sulfides. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:7391-7399. [PMID: 31173690 PMCID: PMC8412064 DOI: 10.1021/acs.est.9b00768] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The potential for inorganic mercury (Hg) to be converted to methylmercury depends, in part, on the chemical form of Hg and its bioavailability to anaerobic microorganisms that can methylate Hg. In anaerobic settings, Hg can be associated with sulfide phases, including ferrous iron sulfide (FeS), which can sorb or be coprecipitated with Hg. The objective of this study was to determine if the aging state of FeS alters the Hg coordination environment as well as the reactivity and bioavailability of sorbed and coprecipitated Hg species. FeS particles were synthesized with and without Hg2+ and aged in anaerobic conditions for multiple time frames spanning from 1 h to 1 month. For FeS particles synthesized without Hg, Hg2+ was subsequently sorbed to the FeS for 1 day. Analysis of Hg speciation of these materials by X-ray absorption near edge spectroscopy revealed a predominance of four-coordinate Hg-S species in the sorbed Hg-FeS solids and a mixture of two- and four-coordinate Hg-S in the coprecipitated Hg-FeS. The leaching potential of the Hg was assessed by exposing the particles to a solution of dissolved glutathione (a thiolate-based Hg chelator). As expected, the sorbed Hg-FeS released more soluble Hg compared to the coprecipitated Hg-FeS. However, when these particles were exposed to Desulfovibrio desulfuricans ND132 (a known Hg methylator), more Hg was methylated from the coprecipitated Hg-FeS than the sorbed Hg-FeS, consistent with expectations from the Hg-S coordination state and inconsistent with the selective leaching results. Overall, these results suggest that the bioavailability of particulate Hg cannot be easily discerned by its leaching potential into bulk solution. Rather, bioavailability entails more subtle interactions at particle-cell interfaces and perhaps correlates with the local Hg-S coordination state in the particles.
Collapse
Affiliation(s)
- Nelson A. Rivera
- Department of Civil and Environmental Engineering, Box 90287, Duke University, Durham, North Carolina 27708, USA
| | - Paige M. Bippus
- Department of Civil and Environmental Engineering, Box 90287, Duke University, Durham, North Carolina 27708, USA
| | - Heileen Hsu-Kim
- Department of Civil and Environmental Engineering, Box 90287, Duke University, Durham, North Carolina 27708, USA
| |
Collapse
|
24
|
Custer TW, Custer CM, Dummer PM, Goldberg D, Franson JC. Element Concentrations in Tree Swallows (Tachycineta bicolor) from the U.S. and Binational Great Lakes Areas of Concern. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2019; 76:414-424. [PMID: 30734087 DOI: 10.1007/s00244-019-00601-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 01/24/2019] [Indexed: 06/09/2023]
Abstract
Selected elements were targeted in state Remedial Action Plans as one group of chemicals affecting the Beneficial Use Impairments of Great Lakes Areas of Concern (AOCs). Livers of nestling tree swallows, Tachycineta bicolor, were harvested from 76 sites in the Great Lakes, which included multiple sites at 27 AOCs and 12 reference sites from 2010 to 2015, and were analyzed for 21 elements. Mercury concentrations were at background levels at all sites. Elevated cadmium (Cd) concentrations were associated with industry. The highest Cd values were from the Black River, OH AOC and were associated with historic coke production but were not at toxic levels. Lead (Pb) concentrations were highest on the Rouge River, MI AOC-the oldest and most heavily populated and industrialized area in southeast Michigan. Individual Pb concentrations were elevated to a level associated with delta-aminolaevulinic acid dehydratase inhibition but not to a level considered toxic. In contrast, livers harvested from sites on the southwest shore of Lake Michigan had selenium (Se) concentrations elevated to levels associated with reduced avian reproduction. One likely source of the high Se concentrations was pollution from a local coal-fired power plant. Concentrations of the remaining elements were at background levels.
Collapse
Affiliation(s)
- Thomas W Custer
- Upper Midwest Environmental Sciences Center, U.S. Geological Survey, La Crosse, WI, 54603, USA
| | - Christine M Custer
- Upper Midwest Environmental Sciences Center, U.S. Geological Survey, La Crosse, WI, 54603, USA.
| | - Paul M Dummer
- Upper Midwest Environmental Sciences Center, U.S. Geological Survey, La Crosse, WI, 54603, USA
| | - Diana Goldberg
- National Wildlife Health Center, U.S. Geological Survey, Madison, WI, 53711, USA
| | - J Christian Franson
- National Wildlife Health Center, U.S. Geological Survey, Madison, WI, 53711, USA
| |
Collapse
|
25
|
Schwartz GE, Sanders JP, McBurney AM, Brown SS, Ghosh U, Gilmour CC. Impact of dissolved organic matter on mercury and methylmercury sorption to activated carbon in soils: implications for remediation. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:485-496. [PMID: 30724289 DOI: 10.1039/c8em00469b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Activated carbon (AC) amendments have shown promise in reducing inorganic mercury (Hg(ii) complexes, "Hg") and methylmercury (MeHg) risk in contaminated soils. However, the effectiveness of AC in Hg and MeHg immobilization has varied among studies, suggesting that site biogeochemistry might dictate efficacy. In this study, we examined the effect of dissolved organic matter (DOM) on MeHg and Hg sorption to AC. We evaluated the impact of Suwannee River Humic Acid (SRHA) on sorption to AC directly using an isotherm approach and in a soil/AC mixture using slurry microcosms. Aqueous sorption coefficients to AC (log KAC) for Hg-SRHA and MeHg-SRHA complexes were one to two orders of magnitude lower (Hg-SRHA = 4.53, MeHgSRHA = 4.35) than those for chloride complexes (HgCl2 = 6.55, MeHgCl = 4.90) and more closely resembled the log KAC of SRHA (3.64). In anoxic, sulfidic soil slurries, the KAC for sulfide species appeared stronger than for chloride or SRHA species for both Hg and MeHg. AC significantly reduced porewater concentrations of both ambient MeHg and a fresh Me199Hg spike, and the addition of up to 60 mg L-1 SRHA did not reduce sorption to AC. The AC also reduced ambient Hg and 201Hg porewater concentrations, but as SRHA concentration increased, the magnitude of solid phase sorption decreased. Speciation modeling revealed that SRHA may have impacted Hg distribution to the solid phase by reducing HgS precipitation. This study highlights the need for site-specific evaluation of AC efficacy and the value in developing biogeochemical models of AC performance for Hg control.
Collapse
Affiliation(s)
- Grace E Schwartz
- Smithsonian Environmental Research Center, 647 Contees Wharf Rd, Edgewater, MD 21037, USA.
| | | | | | | | | | | |
Collapse
|
26
|
Zhang J, Wu S, Xu Z, Wang M, Man YB, Christie P, Liang P, Shan S, Wong MH. The role of sewage sludge biochar in methylmercury formation and accumulation in rice. CHEMOSPHERE 2019; 218:527-533. [PMID: 30500713 DOI: 10.1016/j.chemosphere.2018.11.090] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 10/20/2018] [Accepted: 11/12/2018] [Indexed: 06/09/2023]
Abstract
Methylmercury (MeHg) can accumulate in rice and this has been demonstrated to be an important human MeHg exposure pathway. How to reduce MeHg concentrations in rice grains has therefore become a very important public health issue. Previous studies have investigated the role of plant biochars on Hg bioavailability in soils but knowledge of the influence of sewage sludge biochars (SSB) on MeHg formation and bioaccumulation in different soils is lacking. In the present study, SSB was applied to two Hg-contaminated soils, one acid and the other calcareous, in an attempt to stabilize MeHg in the soil and further mitigate MeHg accumulation in rice grains. The results indicate that the presence of SSB may promote Hg methylation in an acid soil. Moreover, MeHg concentrations increased gradually during rice growth, perhaps due to the release of root exudates. SSB can inhibit both MeHg and total Hg (THg) accumulation in different rice tissues. Both MeHg and THg decreased in the rice grains by up to 73.4 and 81.9%, respectively. However, the inhibitory effect was less pronounced in a calcareous soil. This study further demonstrates that biochar application can inhibit MeHg accumulation in soils despite the promotion of MeHg formation in soil by SSB application. However, an effect of biochar on MeHg accumulation was observed only in the acid soil. These results are useful in managing applications of biochars to Hg-contaminated paddy fields.
Collapse
Affiliation(s)
- Jin Zhang
- Zhejiang Province Key Laboratory of Recycling and Eco-Treatment of Waste Biomass, School of Environment and Natural Resources, Zhejiang University of Science and Technology, Hangzhou, 310023, China
| | - Shengchun Wu
- Zhejiang Province Key Laboratory of Soil Contamination and Bioremediation, School of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China
| | - Zhentao Xu
- Zhejiang Province Key Laboratory of Soil Contamination and Bioremediation, School of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China
| | - Minyan Wang
- Jiyang College, Zhejiang Agriculture and Forestry University, Zhuji, 311800, China
| | - Yu Bon Man
- Consortium on Health, Environment, Education and Research (CHEER), Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, Hong Kong SAR
| | - Peter Christie
- Zhejiang Province Key Laboratory of Recycling and Eco-Treatment of Waste Biomass, School of Environment and Natural Resources, Zhejiang University of Science and Technology, Hangzhou, 310023, China
| | - Peng Liang
- Zhejiang Province Key Laboratory of Soil Contamination and Bioremediation, School of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China.
| | - Shengdao Shan
- Zhejiang Province Key Laboratory of Recycling and Eco-Treatment of Waste Biomass, School of Environment and Natural Resources, Zhejiang University of Science and Technology, Hangzhou, 310023, China.
| | - Ming Hung Wong
- Consortium on Health, Environment, Education and Research (CHEER), Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, Hong Kong SAR
| |
Collapse
|
27
|
Osmundson BC, Lusk JD. Field Assessment of Colorado pikeminnow Exposure to Mercury Within Its Designated Critical Habitat in Colorado, Utah, and New Mexico. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2019; 76:17-30. [PMID: 30259077 PMCID: PMC6326962 DOI: 10.1007/s00244-018-0566-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 09/17/2018] [Indexed: 06/08/2023]
Abstract
Mercury contamination in freshwater fish is widespread across North America, including the western United States. Atmospheric mercury from both natural and manmade emissions deposits into watersheds and, through methylation and biomagnification, accumulates in aquatic food webs. Highest mercury concentrations are found in predatory fish. The endangered Colorado pikeminnow (Ptychocheilus lucius) is a long-lived, top-level piscivore endemic to the Colorado River basin. Mercury exposure to Colorado pikeminnow and another native fish species, the roundtail chub (Gila robusta), was assessed by analyzing muscle tissues collected using a nonlethal technique. Mercury concentrations in Colorado pikeminnow > 400-mm long, captured from critical habitat throughout the species' present range, exceeded the tissue threshold-effect level of 0.2 µg/g wet weight (WW) for whole body fish (0.31 µg/g WW in muscle) recommended to protect fish from injury. Mercury is a neurotoxin and endocrine disruptor, and impacts to fish may include reduced ability to avoid predators, secure food, and reproduce. The highest mercury concentrations were found in both Colorado pikeminnow and roundtail chub collected from the White River, a tributary to the Green River. Colorado pikeminnow from the White and Green rivers had the highest mean mercury concentrations and the lowest mean relative body conditions. Exposure to high mercury concentrations may act in concert with other threatening factors to compromise Colorado pikeminnow population viability and eventual recovery.
Collapse
Affiliation(s)
- Barbara C Osmundson
- Colorado Ecological Services, Western Colorado Field Office, US Fish and Wildlife Service, 445 West Gunnison Ave., Suite 240, Grand Junction, CO, 81501-5711, USA.
- , 380 34 Road, Palisade, CO, 81526, USA.
| | - Joel D Lusk
- New Mexico Ecological Services, US Fish and Wildlife Service, 2105 Osuna Road NE, Albuquerque, NM, 87113-1001, USA.
| |
Collapse
|
28
|
Bravo AG, Kothawala DN, Attermeyer K, Tessier E, Bodmer P, Ledesma JLJ, Audet J, Casas-Ruiz JP, Catalán N, Cauvy-Fraunié S, Colls M, Deininger A, Evtimova VV, Fonvielle JA, Fuß T, Gilbert P, Herrero Ortega S, Liu L, Mendoza-Lera C, Monteiro J, Mor JR, Nagler M, Niedrist GH, Nydahl AC, Pastor A, Pegg J, Gutmann Roberts C, Pilotto F, Portela AP, González-Quijano CR, Romero F, Rulík M, Amouroux D. The interplay between total mercury, methylmercury and dissolved organic matter in fluvial systems: A latitudinal study across Europe. WATER RESEARCH 2018; 144:172-182. [PMID: 30029076 DOI: 10.1016/j.watres.2018.06.064] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 06/27/2018] [Accepted: 06/28/2018] [Indexed: 05/16/2023]
Abstract
Large-scale studies are needed to identify the drivers of total mercury (THg) and monomethyl-mercury (MeHg) concentrations in aquatic ecosystems. Studies attempting to link dissolved organic matter (DOM) to levels of THg or MeHg are few and geographically constrained. Additionally, stream and river systems have been understudied as compared to lakes. Hence, the aim of this study was to examine the influence of DOM concentration and composition, morphological descriptors, land uses and water chemistry on THg and MeHg concentrations and the percentage of THg as MeHg (%MeHg) in 29 streams across Europe spanning from 41°N to 64 °N. THg concentrations (0.06-2.78 ng L-1) were highest in streams characterized by DOM with a high terrestrial soil signature and low nutrient content. MeHg concentrations (7.8-159 pg L-1) varied non-systematically across systems. Relationships between DOM bulk characteristics and THg and MeHg suggest that while soil derived DOM inputs control THg concentrations, autochthonous DOM (aquatically produced) and the availability of electron acceptors for Hg methylating microorganisms (e.g. sulfate) drive %MeHg and potentially MeHg concentration. Overall, these results highlight the large spatial variability in THg and MeHg concentrations at the European scale, and underscore the importance of DOM composition on mercury cycling in fluvial systems.
Collapse
Affiliation(s)
- Andrea G Bravo
- Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Spanish National Research Council (CSIC), Barcelona, Spain.
| | - Dolly N Kothawala
- Limnology/Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Katrin Attermeyer
- Limnology/Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Emmanuel Tessier
- CNRS/ UNIV PAU & PAYS ADOUR, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Materiaux, UMR5254, MIRA, Pau, France
| | - Pascal Bodmer
- Institute for Environmental Sciences, University of Koblenz-Landau, Landau, Germany; Chemical Analytics and Biogeochemistry, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
| | - José L J Ledesma
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Joachim Audet
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | | | - Núria Catalán
- Catalan Institute for Water Research (ICRA), Girona, Spain
| | | | - Miriam Colls
- Catalan Institute for Water Research (ICRA), Girona, Spain
| | - Anne Deininger
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Vesela V Evtimova
- Department of Aquatic Ecosystems, Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Jérémy A Fonvielle
- Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Stechlin, Germany
| | - Thomas Fuß
- Ecohydrology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany; WasserCluster Biological Station Lunz, Lunz am See, Austria
| | - Peter Gilbert
- The Environmental Research Institute, North Highland College, University of Highlands and Islands, Thurso, Scotland, UK
| | - Sonia Herrero Ortega
- Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Stechlin, Germany
| | - Liu Liu
- Institute for Environmental Sciences, University of Koblenz-Landau, Landau, Germany
| | - Clara Mendoza-Lera
- IRSTEA, UR RiverLy, Centre de Lyon-Villeurbanne, Villeurbanne, Cedex, France
| | - Juliana Monteiro
- Research Centre in Biodiversity and Genetic Resources (CIBIO), University of Porto, Porto, Portugal
| | - Jordi-René Mor
- Catalan Institute for Water Research (ICRA), Girona, Spain; Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, University of Barcelona (UB), Barcelona, Spain
| | - Magdalena Nagler
- Microbial Resource Management, Institute of Microbiology, University of Innsbruck, Innsbruck, Austria
| | - Georg H Niedrist
- River and Conservation Research, Institute of Ecology, University of Innsbruck, Innsbruck, Austria
| | - Anna C Nydahl
- Limnology/Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Ada Pastor
- Catalan Institute for Water Research (ICRA), Girona, Spain
| | - Josephine Pegg
- Department of Life and Environmental Sciences, Bournemouth University, UK; University Centre Sparsholt, Winchester, UK
| | | | - Francesca Pilotto
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Ana Paula Portela
- Research Centre in Biodiversity and Genetic Resources (CIBIO), University of Porto, Porto, Portugal
| | | | - Ferran Romero
- Catalan Institute for Water Research (ICRA), Girona, Spain
| | - Martin Rulík
- Department of Ecology and Environmental Sciences, Palacky University in Olomouc, Olomouc, Czech Republic
| | - David Amouroux
- CNRS/ UNIV PAU & PAYS ADOUR, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Materiaux, UMR5254, MIRA, Pau, France.
| |
Collapse
|
29
|
Kelly CA, Rudd JWM. Transport of mercury on the finest particles results in high sediment concentrations in the absence of significant ongoing sources. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 637-638:1471-1479. [PMID: 29801240 DOI: 10.1016/j.scitotenv.2018.04.234] [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: 12/30/2017] [Revised: 04/16/2018] [Accepted: 04/17/2018] [Indexed: 06/08/2023]
Abstract
The mercury contaminated upper Penobscot Estuary in Maine provided a unique opportunity to rigorously examine the effect of sediment type and particle size on mercury concentrations in sediments, and to explain why sediments at different locations in the estuary had different mercury concentrations. This is because the Penobscot Estuary contains a large, well-mixed pool of mobile sediments of many different types (muds, sand, gravel, wood chips), which are the source of material for the permanently deposited surface sediments. Despite this mixing, average surface sediment mercury concentrations were very different in different locations, ranging from 238 ng/gdw to 1032 ng/gdw in the 11 subareas studied. Average total mercury concentrations were highly related to the type of sediment (wood chips > muds > sands) regardless of location in the estuary. The characteristics in both mobile and surface sediments that were positively related to total mercury concentrations were % organic matter (measured as loss on ignition) and %fines (measured usually as <62.5 μ). Also, in a subset of samples it was shown that mercury was positively associated only with the very finest (<44 μ) particles. Thus, side embayments of the estuary such as the Orland River and Mendall Marsh, which experience lower velocity currents and so accumulate more fine particles, tended to be much higher in mercury concentrations. This knowledge will be important in managing remediation of this system, as fine particles can be the most difficult to trap or to retain if dredging is employed. Methyl mercury was well correlated with total mercury and so its distribution would also be affected by transport characteristics. This was the case even in the mobile sediments, which were more oxic and not expected to provide a good habitat for methylation.
Collapse
Affiliation(s)
- Carol A Kelly
- R&K Research Inc., 675 Mount Belcher Heights, Salt Spring Island, BC V8K 2J3, Canada.
| | - John W M Rudd
- R&K Research Inc., 675 Mount Belcher Heights, Salt Spring Island, BC V8K 2J3, Canada
| |
Collapse
|
30
|
Petranich E, Covelli S, Acquavita A, Faganeli J, Horvat M, Contin M. Evaluation of mercury biogeochemical cycling at the sediment-water interface in anthropogenically modified lagoon environments. J Environ Sci (China) 2018; 68:5-23. [PMID: 29908744 DOI: 10.1016/j.jes.2017.11.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/08/2017] [Accepted: 11/10/2017] [Indexed: 05/17/2023]
Abstract
The Marano and Grado Lagoon is well known for being contaminated by mercury (Hg) from the Idrija mine (Slovenia) and the decommissioned chlor-alkali plant of Torviscosa (Italy). Experimental activities were conducted in a local fish farm to understand Hg cycling at the sediment-water interface. Both diffusive and benthic fluxes were estimated in terms of chemical and physical features. Mercury concentration in sediments (up to 6.81μg/g) showed a slight variability with depth, whereas the highest methylmercury (MeHg) values (up to 10ng/g) were detected in the first centimetres. MeHg seems to be produced and stored in the 2-3cm below the sediment-water interface, where sulphate reducing bacteria activity occurs and hypoxic-anoxic conditions become persistent for days. DMeHg in porewaters varied seasonally (from 0.1 and 17% of dissolved Hg (DHg)) with the highest concentrations in summer. DHg diffusive effluxes higher (up to 444ng/m2/day) than those reported in the open lagoon (~95ng/m2/day), whereas DMeHg showed influxes in the fish farm (up to -156ng/m2/day). The diurnal DHg and DMeHg benthic fluxes were found to be higher than the highest summer values previously reported for the natural lagoon environment. Bottom sediments, especially in anoxic conditions, seem to be a significant source of MeHg in the water column where it eventually accumulates. However, net fluxes considering the daily trend of DHg and DMeHg, indicated possible DMeHg degradation processes. Enhancing water dynamics in the fish farm could mitigate environmental conditions suitable for Hg methylation.
Collapse
Affiliation(s)
- Elisa Petranich
- Dipartimento di Matematica e Geoscienze, Università degli Studi di Trieste, Via Weiss 2, 34128 Trieste, Italy; Dipartimento di Scienze della Vita, Università degli Studi di Trieste, Via Licio Giorgieri 5, 34128 Trieste, Italy
| | - Stefano Covelli
- Dipartimento di Matematica e Geoscienze, Università degli Studi di Trieste, Via Weiss 2, 34128 Trieste, Italy; CoN.I.S.Ma. Consorzio Nazionale Interuniversitario per le Scienze del Mare, Piazzale Flaminio 9, 00196 Rome, Italy.
| | - Alessandro Acquavita
- Agenzia Regionale per la Protezione Ambientale del Friuli Venezia Giulia, ARPA FVG, Via Cairoli 14, 33057 Palmanova (Udine), Italy
| | | | - Milena Horvat
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Marco Contin
- Dipartimento di Scienze Agro-Alimentari, Ambientali e Animali, Università di Udine, Via delle Scienze 206, 33100 Udine, Italy
| |
Collapse
|
31
|
Gilmour C, Bell T, Soren A, Riedel G, Riedel G, Kopec D, Bodaly D, Ghosh U. Activated carbon thin-layer placement as an in situ mercury remediation tool in a Penobscot River salt marsh. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 621:839-848. [PMID: 29216592 DOI: 10.1016/j.scitotenv.2017.11.050] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 11/02/2017] [Accepted: 11/04/2017] [Indexed: 06/07/2023]
Abstract
The efficacy of thin layer in situ soil amendments was tested as a potential tool for methylmercury (MeHg) risk mitigation in Penobscot River, ME, salt marsh. Salt marshes are sites of high MeHg accumulation within the Penobscot, and key targets for remediation. The study was a fully-crossed small plot study, with four treatments (activated carbon (AC), biochar, FeCl2, and lime) and unamended controls at two sites. Plots were monitored for two years. Porewater MeHg concentrations were the main endpoint, with impacts on sediment biogeochemistry as a secondary study goal. AC-based SediMite™ was effective in reducing MeHg, and to a less extent total Hg, in surficial pore waters. AC reduced MeHg concentrations by >90% at the one month time point, and continued to significantly reduce pore water MeHg through about a year. AC was less effective in reducing total Hg in pore water, yielding about 70% reduction at one month, and 50-65% reduction at 8months. Biochar provided lower, and more variable reduction in porewater MeHg, but was not effective in reducing total Hg. Biochar amendment also increased soil MeHg. Neither FeCl2 nor lime amendments reduced pore water Hg or MeHg levels. About 50% of AC treatment applied as SediMite™ pellets was retained in marsh soils after one year. This study is one of the first field trials of in situ amendment for MeHg remediation. Our results show that thin-layer AC placement is a potential remediation tool for Hg risk to biota, especially in marshes where net MeHg accumulation is often strong.
Collapse
Affiliation(s)
- Cynthia Gilmour
- Smithsonian Environmental Research Center, 647 Contees Wharf Rd., Edgewater, MD 20657, United States.
| | - Tyler Bell
- Smithsonian Environmental Research Center, 647 Contees Wharf Rd., Edgewater, MD 20657, United States
| | - Ally Soren
- Smithsonian Environmental Research Center, 647 Contees Wharf Rd., Edgewater, MD 20657, United States
| | - Georgia Riedel
- Smithsonian Environmental Research Center, 647 Contees Wharf Rd., Edgewater, MD 20657, United States
| | - Gerhardt Riedel
- Smithsonian Environmental Research Center, 647 Contees Wharf Rd., Edgewater, MD 20657, United States
| | - Dianne Kopec
- Penobscot River Mercury Study, Bangor, ME, United States
| | - Drew Bodaly
- Penobscot River Mercury Study, Bangor, ME, United States
| | - Upal Ghosh
- University of Maryland Baltimore County, Chemical, Biochemical and Environmental Engineering, Baltimore, MD, United States
| |
Collapse
|
32
|
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: 128] [Impact Index Per Article: 21.3] [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.
Collapse
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
| |
Collapse
|
33
|
Kasper D, Forsberg BR, Amaral JHF, Py-Daniel SS, Bastos WR, Malm O. Methylmercury Modulation in Amazon Rivers Linked to Basin Characteristics and Seasonal Flood-Pulse. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:14182-14191. [PMID: 29172464 DOI: 10.1021/acs.est.7b04374] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We investigated the impact of the seasonal inundation of wetlands on methylmercury (MeHg) concentration dynamics in the Amazon river system. We sampled 38 sites along the Solimões/Amazon and Negro rivers and their tributaries during distinct phases of the annual flood-pulse. MeHg dynamics in both basins was contrasted to provide insight into the factors controlling export of MeHg to the Amazon system. The export of MeHg by rivers was substantially higher during high-water in both basins since elevated MeHg concentrations and discharge occurred during this time. MeHg concentration was positively correlated to %flooded area upstream of the sampling site in the Solimões/Amazon Basin with the best correlation obtained using 100 km buffers instead of whole basin areas. The lower correlations obtained with the whole basin apparently reflected variable losses of MeHg exported from upstream wetlands due to demethylation, absorption, deposition, and degradation before reaching the sampling site. A similar correlation between %flooded area and MeHg concentrations was not observed in the Negro Basin probably due to the variable export of MeHg from poorly drained soils that are abundant in this basin but not consistently flooded.
Collapse
Affiliation(s)
- Daniele Kasper
- Departamento de Dinâmica Ambiental, Instituto Nacional de Pesquisas da Amazônia , Av. Ephigênio Salles, 2239, Manaus, Amazonas 69060-020, Brazil
- Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro , Ilha do Fundão, Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Bruce R Forsberg
- Departamento de Dinâmica Ambiental, Instituto Nacional de Pesquisas da Amazônia , Av. Ephigênio Salles, 2239, Manaus, Amazonas 69060-020, Brazil
| | - João H F Amaral
- Departamento de Dinâmica Ambiental, Instituto Nacional de Pesquisas da Amazônia , Av. Ephigênio Salles, 2239, Manaus, Amazonas 69060-020, Brazil
| | - Sarah S Py-Daniel
- Departamento de Dinâmica Ambiental, Instituto Nacional de Pesquisas da Amazônia , Av. Ephigênio Salles, 2239, Manaus, Amazonas 69060-020, Brazil
| | - Wanderley R Bastos
- Universidade Federal de Rondônia, BR 364 km 9,6 sentido Acre, Porto Velho, Rondônia 76815-800, Brazil
| | - Olaf Malm
- Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro , Ilha do Fundão, Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| |
Collapse
|
34
|
Valdes C, Black FJ, Stringham B, Collins JN, Goodman JR, Saxton HJ, Mansfield CR, Schmidt JN, Yang S, Johnson WP. Total Mercury and Methylmercury Response in Water, Sediment, and Biota to Destratification of the Great Salt Lake, Utah, United States. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:4887-4896. [PMID: 28399629 DOI: 10.1021/acs.est.6b05790] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Measurements of chemical and physical parameters made before and after sealing of culverts in the railroad causeway spanning the Great Salt Lake in late 2013 documented dramatic alterations in the system in response to the elimination of flow between the Great Salt Lake's north and south arms. The flow of denser, more-saline water through the culverts from the north arm (Gunnison Bay) to the south arm (Gilbert Bay) previously drove the perennial stratification of the south arm and the existence of oxic shallow brine and anoxic deep brine layers. Closure of the causeway culverts occurred concurrently with a multiyear drought that resulted in a decrease in the lake elevation and a concomitant increase in top-down erosion of the upper surface of the deep brine layer by wind-forced mixing. The combination of these events resulted in the replacement of the formerly stratified water column in the south arm with one that was vertically homogeneous and oxic. Total mercury concentrations in the deep waters of the south arm decreased by approximately 81% and methylmercury concentrations in deep waters decreased by roughly 86% due to destratification. Methylmercury concentrations decreased by 77% in underlying surficial sediment, whereas there was no change observed in total mercury. The dramatic mercury loss from deep waters and methylmercury loss from underlying sediment in response to causeway sealing provides new understanding of the potential role of the deep brine layer in the accumulation and persistence of methylmercury in the Great Salt Lake. Additional mercury measurements in biota appear to contradict the previously implied connection between elevated methylmercury concentrations in the deep brine layer and elevated mercury in avian species reported prior to causeway sealing.
Collapse
Affiliation(s)
- Carla Valdes
- Department of Geology & Geophysics, University of Utah , Salt Lake City, Utah 84112, United States
| | - Frank J Black
- Department of Chemistry, Westminster College , Salt Lake City, Utah 84105, United States
| | - Blair Stringham
- Division of Wildlife Resources, Utah Department of Natural Resources , Salt Lake City, Utah 84114, United States
| | - Jeffrey N Collins
- Department of Chemistry, Westminster College , Salt Lake City, Utah 84105, United States
| | - James R Goodman
- Department of Chemistry, Westminster College , Salt Lake City, Utah 84105, United States
| | - Heidi J Saxton
- Department of Chemistry, Westminster College , Salt Lake City, Utah 84105, United States
| | | | - Joshua N Schmidt
- Department of Chemistry, Westminster College , Salt Lake City, Utah 84105, United States
| | - Shu Yang
- Department of Geology & Geophysics, University of Utah , Salt Lake City, Utah 84112, United States
| | - William P Johnson
- Department of Geology & Geophysics, University of Utah , Salt Lake City, Utah 84112, United States
| |
Collapse
|
35
|
Boyd ES, Yu RQ, Barkay T, Hamilton TL, Baxter BK, Naftz DL, Marvin-DiPasquale M. Effect of salinity on mercury methylating benthic microbes and their activities in Great Salt Lake, Utah. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 581-582:495-506. [PMID: 28057343 DOI: 10.1016/j.scitotenv.2016.12.157] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 12/22/2016] [Accepted: 12/22/2016] [Indexed: 06/06/2023]
Abstract
Surface water and biota from Great Salt Lake (GSL) contain some of the highest documented concentrations of total mercury (THg) and methylmercury (MeHg) in the United States. In order to identify potential biological sources of MeHg and controls on its production in this ecosystem, THg and MeHg concentrations, rates of Hg(II)-methylation and MeHg degradation, and abundances and compositions of archaeal and bacterial 16 rRNA gene transcripts were determined in sediment along a salinity gradient in GSL. Rates of Hg(II)-methylation were inversely correlated with salinity and were at or below the limits of detection in sediment sampled from areas with hypersaline surface water. The highest rates of Hg(II)-methylation were measured in sediment with low porewater salinity, suggesting that benthic microbial communities inhabiting less saline environments are supplying the majority of MeHg in the GSL ecosystem. The abundance of 16S rRNA gene transcripts affiliated with the sulfate reducer Desulfobacterium sp. was positively correlated with MeHg concentrations and Hg(II)-methylation rates in sediment, indicating a potential role for this taxon in Hg(II)-methylation in low salinity areas of GSL. Reactive inorganic Hg(II) (a proxy used for Hg(II) available for methylation) and MeHg concentrations were inversely correlated with salinity. Thus, constraints imposed by salinity on Hg(II)-methylating populations and the availability of Hg(II) for methylation are inferred to result in higher MeHg production potentials in lower salinity environments. Benthic microbial MeHg degradation was also most active in lower salinity environments. Collectively, these results suggest an important role for sediment anoxia and microbial sulfate reducers in the production of MeHg in low salinity GSL sub-habitats and may indicate a role for salinity in constraining Hg(II)-methylation and MeHg degradation activities by influencing the availability of Hg(II) for methylation.
Collapse
Affiliation(s)
- Eric S Boyd
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, United States.
| | - Ri-Qing Yu
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ 08901, United States
| | - Tamar Barkay
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ 08901, United States
| | - Trinity L Hamilton
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, United States
| | - Bonnie K Baxter
- Department of Biology, Westminster College, Salt Lake City, UT 84105, United States
| | - David L Naftz
- United States Geological Survey, Helena, MT 59601, United States
| | | |
Collapse
|
36
|
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.
Collapse
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
| |
Collapse
|
37
|
Mercury and Organic Matter Concentrations in Lake and Stream Sediments in relation to One Another and to Atmospheric Mercury Deposition and Climate Variations across Canada. J CHEM-NY 2017. [DOI: 10.1155/2017/8949502] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This article focuses on analyzing the Geological Survey of Canada (GSC) data for total mercury concentrations (THg) in lake and stream sediments. The objective was to quantify how sediment THg varies by (i) sediment organic matter, determined by loss on ignition (LOI) at 500∘C, (ii) atmospheric Hg deposition (atm.Hgdep) as derived from the Global/Regional Atmospheric Heavy Metals Model GRAHM2005, and (iii) mean annual precipitation and mean monthly July and January temperatures (TJuly,TJan). Through regression analyses and averaging by National Topographic System tiles (NTS, 1:250,000 scale), it was found that 40, 70, and 80% of the sediment THg, LOI, and atm.Hgdepvariations were, respectively, related to precipitation,TJuly, andTJan. In detail, lake sediment THg was related to atm.Hgdepand precipitation, while stream sediment THg was related to sediment LOI andTJuly. Plotting sediment THg versus sediment LOI revealed a curvilinear pattern, with highest Hg concentrations at intermediate LOI values. Analysing the resulting 10th and 90th log10THg percentiles within each 10% LOI class from 0 to 100% revealed that (i) atm.Hgdepcontributed to the organic component of sediment THg and (ii) this was more pronounced for lakes than for streams.
Collapse
|
38
|
Alpers CN, Yee JL, Ackerman JT, Orlando JL, Slotton DG, Marvin-DiPasquale MC. Prediction of fish and sediment mercury in streams using landscape variables and historical mining. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 571:364-379. [PMID: 27378154 DOI: 10.1016/j.scitotenv.2016.05.088] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Revised: 05/11/2016] [Accepted: 05/13/2016] [Indexed: 06/06/2023]
Abstract
Widespread mercury (Hg) contamination of aquatic systems in the Sierra Nevada of California, U.S., is associated with historical use to enhance gold (Au) recovery by amalgamation. In areas affected by historical Au mining operations, including the western slope of the Sierra Nevada and downstream areas in northern California, such as San Francisco Bay and the Sacramento River-San Joaquin River Delta, microbial conversion of Hg to methylmercury (MeHg) leads to bioaccumulation of MeHg in food webs, and increased risks to humans and wildlife. This study focused on developing a predictive model for THg in stream fish tissue based on geospatial data, including land use/land cover data, and the distribution of legacy Au mines. Data on total mercury (THg) and MeHg concentrations in fish tissue and streambed sediment collected during 1980-2012 from stream sites in the Sierra Nevada, California were combined with geospatial data to estimate fish THg concentrations across the landscape. THg concentrations of five fish species (Brown Trout, Rainbow Trout, Sacramento Pikeminnow, Sacramento Sucker, and Smallmouth Bass) within stream sections were predicted using multi-model inference based on Akaike Information Criteria, using geospatial data for mining history and landscape characteristics as well as fish species and length (r(2)=0.61, p<0.001). Including THg concentrations in streambed sediment did not improve the model's fit, however including MeHg concentrations in streambed sediment, organic content (loss on ignition), and sediment grain size resulted in an improved fit (r(2)=0.63, p<0.001). These models can be used to estimate THg concentrations in stream fish based on landscape variables in the Sierra Nevada in areas where direct measurements of THg concentration in fish are unavailable.
Collapse
Affiliation(s)
- Charles N Alpers
- U.S. Geological Survey, California Water Science Center, 6000 J Street, Placer Hall, Sacramento, CA 95819, U.S.A..
| | - Julie L Yee
- U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive, Suite D, Dixon, CA 95620, U.S.A
| | - Joshua T Ackerman
- U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive, Suite D, Dixon, CA 95620, U.S.A
| | - James L Orlando
- U.S. Geological Survey, California Water Science Center, 6000 J Street, Placer Hall, Sacramento, CA 95819, U.S.A
| | - Darrel G Slotton
- Dept. of Environmental Science and Policy, Univ. of California, Davis, CA 95616, U.S.A
| | - Mark C Marvin-DiPasquale
- U.S. Geological Survey, National Research Program, 345 Middlefield Road, Menlo Park, CA 94025, U.S.A
| |
Collapse
|
39
|
Fleck JA, Marvin-DiPasquale M, Eagles-Smith CA, Ackerman JT, Lutz MA, Tate M, Alpers CN, Hall BD, Krabbenhoft DP, Eckley CS. Mercury and methylmercury in aquatic sediment across western North America. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 568:727-738. [PMID: 27130329 DOI: 10.1016/j.scitotenv.2016.03.044] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 03/07/2016] [Accepted: 03/07/2016] [Indexed: 05/25/2023]
Abstract
Large-scale assessments are valuable in identifying primary factors controlling total mercury (THg) and monomethyl mercury (MeHg) concentrations, and distribution in aquatic ecosystems. Bed sediment THg and MeHg concentrations were compiled for >16,000 samples collected from aquatic habitats throughout the West between 1965 and 2013. The influence of aquatic feature type (canals, estuaries, lakes, and streams), and environmental setting (agriculture, forest, open-water, range, wetland, and urban) on THg and MeHg concentrations was examined. THg concentrations were highest in lake (29.3±6.5μgkg(-1)) and canal (28.6±6.9μgkg(-1)) sites, and lowest in stream (20.7±4.6μgkg(-1)) and estuarine (23.6±5.6μgkg(-1)) sites, which was partially a result of differences in grain size related to hydrologic gradients. By environmental setting, open-water (36.8±2.2μgkg(-1)) and forested (32.0±2.7μgkg(-1)) sites generally had the highest THg concentrations, followed by wetland sites (28.9±1.7μgkg(-1)), rangeland (25.5±1.5μgkg(-1)), agriculture (23.4±2.0μgkg(-1)), and urban (22.7±2.1μgkg(-1)) sites. MeHg concentrations also were highest in lakes (0.55±0.05μgkg(-1)) and canals (0.54±0.11μgkg(-1)), but, in contrast to THg, MeHg concentrations were lowest in open-water sites (0.22±0.03μgkg(-1)). The median percent MeHg (relative to THg) for the western region was 0.7%, indicating an overall low methylation efficiency; however, a significant subset of data (n>100) had percentages that represent elevated methylation efficiency (>6%). MeHg concentrations were weakly correlated with THg (r(2)=0.25) across western North America. Overall, these results highlight the large spatial variability in sediment THg and MeHg concentrations throughout western North America and underscore the important roles that landscape and land-use characteristics have on the MeHg cycle.
Collapse
Affiliation(s)
- Jacob A Fleck
- United States Geological Survey, California Water Science Center, 6000 J St., Placer Hall, Sacramento, CA 95819, USA.
| | | | - Collin A Eagles-Smith
- United States Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, OR, USA
| | - Joshua T Ackerman
- United States Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive, Suite D, Dixon, CA 95620, USA
| | - Michelle A Lutz
- United States Geological Survey, 8505 Research Way, Middleton, WI 53562, USA
| | - Michael Tate
- United States Geological Survey, 8505 Research Way, Middleton, WI 53562, USA
| | - Charles N Alpers
- United States Geological Survey, California Water Science Center, 6000 J St., Placer Hall, Sacramento, CA 95819, USA
| | - Britt D Hall
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
| | - David P Krabbenhoft
- United States Geological Survey, 8505 Research Way, Middleton, WI 53562, USA
| | - Chris S Eckley
- United States Environmental Protection Agency, 1200 6th Ave, St. 900, OEA-095, Seattle, WA 98101, USA
| |
Collapse
|
40
|
Donovan PM, Blum JD, Singer MB, Marvin-DiPasquale M, Tsui MTK. Methylmercury degradation and exposure pathways in streams and wetlands impacted by historical mining. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 568:1192-1203. [PMID: 27234290 DOI: 10.1016/j.scitotenv.2016.04.139] [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: 01/16/2016] [Revised: 04/19/2016] [Accepted: 04/19/2016] [Indexed: 06/05/2023]
Abstract
Monomethyl mercury (MMHg) and total mercury (THg) concentrations and Hg stable isotope ratios (δ(202)Hg and Δ(199)Hg) were measured in sediment and aquatic organisms from Cache Creek (California Coast Range) and Yolo Bypass (Sacramento Valley). Cache Creek sediment had a large range in THg (87 to 3870ng/g) and δ(202)Hg (-1.69 to -0.20‰) reflecting the heterogeneity of Hg mining sources in sediment. The δ(202)Hg of Yolo Bypass wetland sediment suggests a mixture of high and low THg sediment sources. Relationships between %MMHg (the percent ratio of MMHg to THg) and Hg isotope values (δ(202)Hg and Δ(199)Hg) in fish and macroinvertebrates were used to identify and estimate the isotopic composition of MMHg. Deviation from linear relationships was found between %MMHg and Hg isotope values, which is indicative of the bioaccumulation of isotopically distinct pools of MMHg. The isotopic composition of pre-photodegraded MMHg (i.e., subtracting fractionation from photochemical reactions) was estimated and contrasting relationships were observed between the estimated δ(202)Hg of pre-photodegraded MMHg and sediment IHg. Cache Creek had mass dependent fractionation (MDF; δ(202)Hg) of at least -0.4‰ whereas Yolo Bypass had MDF of +0.2 to +0.5‰. This result supports the hypothesis that Hg isotope fractionation between IHg and MMHg observed in rivers (-MDF) is unique compared to +MDF observed in non-flowing water environments such as wetlands, lakes, and the coastal ocean.
Collapse
Affiliation(s)
- Patrick M Donovan
- University of Michigan, Department of Earth and Environmental Sciences, 1100 N., University Ave., Ann Arbor, MI 48109, USA.
| | - Joel D Blum
- University of Michigan, Department of Earth and Environmental Sciences, 1100 N., University Ave., Ann Arbor, MI 48109, USA
| | - Michael Bliss Singer
- University of St Andrews, Department of Earth and Environmental Sciences, North St., St. Andrews, KY16 9AL, UK; Earth Research Institute, University of California Santa Barbara, Santa Barbara, CA, 91306, USA
| | | | - Martin T K Tsui
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| |
Collapse
|
41
|
Singer MB, Harrison LR, Donovan PM, Blum JD, Marvin-DiPasquale M. Hydrologic indicators of hot spots and hot moments of mercury methylation potential along river corridors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 568:697-711. [PMID: 26994752 DOI: 10.1016/j.scitotenv.2016.03.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 03/01/2016] [Accepted: 03/02/2016] [Indexed: 06/05/2023]
Abstract
The biogeochemical cycling of metals and other contaminants in river-floodplain corridors is controlled by microbial activity responding to dynamic redox conditions. Riverine flooding thus has the potential to affect speciation of redox-sensitive metals such as mercury (Hg). Therefore, inundation history over a period of decades potentially holds information on past production of bioavailable Hg. We investigate this within a Northern California river system with a legacy of landscape-scale 19th century hydraulic gold mining. We combine hydraulic modeling, Hg measurements in sediment and biota, and first-order calculations of mercury transformation to assess the potential role of river floodplains in producing monomethylmercury (MMHg), a neurotoxin which accumulates in local and migratory food webs. We identify frequently inundated floodplain areas, as well as floodplain areas inundated for long periods. We quantify the probability of MMHg production potential (MPP) associated with hydrology in each sector of the river system as a function of the spatial patterns of overbank inundation and drainage, which affect long-term redox history of contaminated sediments. Our findings identify river floodplains as periodic, temporary, yet potentially important, loci of biogeochemical transformation in which contaminants may undergo change during limited periods of the hydrologic record. We suggest that inundation is an important driver of MPP in river corridors and that the entire flow history must be analyzed retrospectively in terms of inundation magnitude and frequency in order to accurately assess biogeochemical risks, rather than merely highlighting the largest floods or low-flow periods. MMHg bioaccumulation within the aquatic food web in this system may pose a major risk to humans and waterfowl that eat migratory salmonids, which are being encouraged to come up these rivers to spawn. There is a long-term pattern of MPP under the current flow regime that is likely to be accentuated by increasingly common large floods with extended duration.
Collapse
Affiliation(s)
- Michael Bliss Singer
- Department of Earth & Environmental Sciences, University of St Andrews, St Andrews, UK; Earth Research Institute, University of California Santa Barbara, Santa Barbara, CA, USA.
| | - Lee R Harrison
- Earth Research Institute, University of California Santa Barbara, Santa Barbara, CA, USA; NOAA Fisheries, Santa Cruz, CA, USA
| | - Patrick M Donovan
- Department of Earth & Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Joel D Blum
- Department of Earth & Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Mark Marvin-DiPasquale
- National Research Program, Water Resources Division, US Geological Survey, Menlo Park, CA, USA
| |
Collapse
|
42
|
Zhao L, Qiu G, Anderson CWN, Meng B, Wang D, Shang L, Yan H, Feng X. Mercury methylation in rice paddies and its possible controlling factors in the Hg mining area, Guizhou province, Southwest China. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 215:1-9. [PMID: 27176759 DOI: 10.1016/j.envpol.2016.05.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 04/24/2016] [Accepted: 05/01/2016] [Indexed: 06/05/2023]
Abstract
Understanding mercury (Hg) methylation/demethylation processes and the factors controlling methylmercury (MeHg) production within the rice paddy ecosystem of Hg mining areas is critical to assess the risk of MeHg contamination in rice grain. Two typical Hg-contaminated mining sites, a current-day artisanal site (Gouxi) and an abandoned site (Wukeng), were chosen in this study. We qualified the in situ specific methylation/demethylation rate constants in rice paddy soil during a complete rice-growing season. Our results demonstrate that MeHg levels in rice paddy soil were a function of both methylation and demethylation processes and the net methylation potential in the rice paddy soil reflected the measured MeHg production at any time point. Sulfate stimulating the activity of sulfate-reducing bacteria was a potentially important metabolic pathway for Hg methylation in rice paddies. We suggest that bioavailable Hg derived from new atmospheric deposition appears to be the primary factor regulating net MeHg production in rice paddies.
Collapse
Affiliation(s)
- Lei Zhao
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, PR China; College of Resources Environment, Southwest University, Chongqing 400716, PR China
| | - Guangle Qiu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, PR China
| | - Christopher W N Anderson
- Soil and Earth Sciences, Institute of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Bo Meng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, PR China.
| | - Dingyong Wang
- College of Resources Environment, Southwest University, Chongqing 400716, PR China
| | - Lihai Shang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, PR China
| | - Haiyu Yan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, PR China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, PR China
| |
Collapse
|
43
|
Tyser RW, Rolfhus KR, Wiener JG, Windels SK, Custer TW, Dummer PM. Mercury Concentrations in Eggs of Red-Winged Blackbirds and Tree Swallows Breeding in Voyageurs National Park, Minnesota. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2016; 71:16-25. [PMID: 26801652 DOI: 10.1007/s00244-016-0263-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 01/11/2016] [Indexed: 06/05/2023]
Abstract
Most investigations of the environmental effects of mercury (Hg) have focused on aquatic food webs that include piscivorous fish or wildlife. However, recent investigations have shown that other species, including passerine songbirds, may also be at risk from exposure to methylmercury (MeHg). We quantified Hg concentrations in eggs of two species of songbirds, red-winged blackbirds (Agelaius phoeniceus) and tree swallows (Tachycineta bicolor), nesting in Voyageurs National Park, Minnesota, USA. Geometric mean concentrations of total Hg (THg) were lower in red-winged blackbird eggs [218 and 107 ng/g dry weight (dw) for 2012 and 2013, respectively] than in tree swallow eggs (228 and 300 ng/g dw for 2012 and 2013, respectively), presumably reflecting differences in the trophic positions of these two species. Concentrations of MeHg averaged 98.4 % of THg in red-winged blackbird eggs. Levels of THg observed in this study were well below critical toxicological benchmarks commonly applied to eggs of avian species, suggesting these breeding populations were not adversely affected by exposure to MeHg. In red-winged blackbirds, concentrations of THg in eggs collected in 2012 were twice those in eggs collected in 2013. Hg levels in eggs of both species increased with date of clutch initiation. In red-winged blackbirds, for example, temporal patterns showed that a 3-week delay in clutch initiation increased egg THg by 60 %. These observations indicate that in ovo exposure of wetland birds to MeHg can vary significantly within nesting season as well as between years.
Collapse
Affiliation(s)
- Robin W Tyser
- River Studies Center, University of Wisconsin-La Crosse, 1725 State Street, La Crosse, WI, 54601, USA.
| | - Kristofer R Rolfhus
- River Studies Center, University of Wisconsin-La Crosse, 1725 State Street, La Crosse, WI, 54601, USA
| | - James G Wiener
- River Studies Center, University of Wisconsin-La Crosse, 1725 State Street, La Crosse, WI, 54601, USA
| | - Steve K Windels
- , Voyageurs National Park, 360 Hwy 11 E, International Falls, MN, 56649, USA
| | - Thomas W Custer
- Upper Midwest Environmental Sciences Center, United States Geological Survey, 2630 Fanta Reed Rd., La Crosse, WI, 54603, USA
| | - Paul M Dummer
- Upper Midwest Environmental Sciences Center, United States Geological Survey, 2630 Fanta Reed Rd., La Crosse, WI, 54603, USA
| |
Collapse
|
44
|
Riscassi A, Miller C, Brooks S. Seasonal and flow-driven dynamics of particulate and dissolved mercury and methylmercury in a stream impacted by an industrial mercury source. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2016; 35:1386-1400. [PMID: 26574732 DOI: 10.1002/etc.3310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 08/21/2015] [Accepted: 11/14/2015] [Indexed: 06/05/2023]
Abstract
Sediments and floodplain soils in the East Fork Poplar Creek watershed (Oak Ridge, TN, USA) are contaminated with high levels of mercury (Hg) from an industrial source at the headwaters. Although baseflow conditions have been monitored, concentrations of Hg and methylmercury (MeHg) during high-flow storm events, when the stream is more hydrologically connected to the floodplain, have yet to be assessed. The present study evaluated baseflow and event-driven Hg and MeHg dynamics in East Fork Poplar Creek, 5 km upstream of the confluence with Poplar Creek, to determine the importance of hydrology to in-stream concentrations and downstream loads and to ascertain whether the dynamics are comparable to those of systems without an industrial Hg source. Particulate Hg and MeHg were positively correlated with discharge (r(2) = 0.64 and 0.58, respectively) and total suspended sediment (r(2) = 0.97 and 0.89, respectively), and dissolved Hg also increased with increasing flow (r(2) = 0.18) and was associated with increases in dissolved organic carbon (r(2) = 0.65), similar to the dynamics observed in uncontaminated systems. Dissolved MeHg decreased with increases in discharge (r(2) = 0.23) and was not related to dissolved organic carbon concentrations (p = 0.56), dynamics comparable to relatively uncontaminated watersheds with a small percentage of wetlands (<10%). Although stormflows exert a dominant control on particulate Hg, particulate MeHg, and dissolved Hg concentrations and loads, baseflows were associated with the highest dissolved MeHg concentration (0.38 ng/L) and represented the majority of the annual dissolved MeHg load. Environ Toxicol Chem 2016;35:1386-1400. Published 2015 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.
Collapse
Affiliation(s)
- Ami Riscassi
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Carrie Miller
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Scott Brooks
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| |
Collapse
|
45
|
Lewis AS, Huntington TG, Marvin-DiPasquale MC, Amirbahman A. Mercury remediation in wetland sediment using zero-valent iron and granular activated carbon. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 212:366-373. [PMID: 26874318 DOI: 10.1016/j.envpol.2015.11.047] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 11/25/2015] [Accepted: 11/26/2015] [Indexed: 06/05/2023]
Abstract
Wetlands are hotspots for production of toxic methylmercury (MeHg) that can bioaccumulate in the food web. The objective of this study was to determine whether the application of zero-valent iron (ZVI) or granular activated carbon (GAC) to wetland sediment could reduce MeHg production and bioavailability to benthic organisms. Field mesocosms were installed in a wetland fringing Hodgdon Pond (Maine, USA), and ZVI and GAC were applied. Pore-water MeHg concentrations were lower in treated compared with untreated mesocosms; however, sediment MeHg, as well as total Hg (THg), concentrations were not significantly different between treated and untreated mesocosms, suggesting that smaller pore-water MeHg concentrations in treated sediment were likely due to adsorption to ZVI and GAC, rather than inhibition of MeHg production. In laboratory experiments with intact vegetated sediment clumps, amendments did not significantly change sediment THg and MeHg concentrations; however, the mean pore-water MeHg and MeHg:THg ratios were lower in the amended sediment than the control. In the laboratory microcosms, snails (Lymnaea stagnalis) accumulated less MeHg in sediment treated with ZVI or GAC. The study results suggest that both GAC and ZVI have potential for reducing MeHg bioaccumulation in wetland sediment.
Collapse
Affiliation(s)
- Ariel S Lewis
- Department of Civil and Environmental Engineering, University of Maine, Orono, ME, USA
| | | | | | - Aria Amirbahman
- Department of Civil and Environmental Engineering, University of Maine, Orono, ME, USA.
| |
Collapse
|
46
|
Nimmo DR, Herrmann SJ, Carsella JS, McGarvy CM, Foutz HP, Herrmann-Hoesing LM, Gregorich JM, Turner JA, Vanden Heuvel BD. Mercury and selenium in fish of Fountain Creek, Colorado (USA): possible sources and implications. SPRINGERPLUS 2016; 5:437. [PMID: 27104125 PMCID: PMC4828357 DOI: 10.1186/s40064-016-2088-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 03/31/2016] [Indexed: 11/10/2022]
Abstract
Fountain Creek in Colorado USA is a major tributary that confluences with the Arkansas River at Pueblo, Colorado, the result being the tributary’s influence on Arkansas River water quality affecting down-stream users. In a previous study, we found that bryophytes (aquatic plants) accumulated selenium in Fountain Creek watershed and this finding prompted us to investigate the extent of the metalloid in the whole-body tissues of fish. One hundred 11 fish (six species) were collected and analyzed for Se by inductively-coupled plasma emission mass spectrometry. Analysis of all analytical data also showed mercury in all of the fish whole bodies and selected tissues. There was a general increase in selenium but a decrease in mercury in fish with downstream travel-distance. The highest whole-body selenium was in Pueblo, Colorado (3393 µg/kg, dry weight; 906 µg/kg, wet weight); the highest mercury in fish was in the Monument Creek tributary north of Colorado Springs, Colorado (71 µg/kg, dry weight; 19 µg/kg, wet weight). In four tissues of 11 female fish captured, selenium was highest in the livers at eight sites but highest in the ovaries at three sites. Mercury was highest in the epaxial muscle at all sites. Selenium availability could be due to the watershed lithology and land uses; however, mercury could be carried by atmospheric deposition from coal-fired power plants and historic mining activities. Selenium in fish tissues and water samples were compared to U.S. national water quality criteria.
Collapse
Affiliation(s)
- D R Nimmo
- Department of Biology, Colorado State University-Pueblo, Pueblo, CO 81001 USA
| | - S J Herrmann
- Department of Biology, Colorado State University-Pueblo, Pueblo, CO 81001 USA
| | - J S Carsella
- Department of Chemistry, Colorado State University-Pueblo, Pueblo, CO 81001 USA
| | - C M McGarvy
- Department of Biology, Colorado State University-Pueblo, Pueblo, CO 81001 USA
| | - H P Foutz
- Division of Colorado Parks and Wildlife, 6060 Broadway, Denver, CO USA
| | - L M Herrmann-Hoesing
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164 USA
| | - J M Gregorich
- Department of Biology, Colorado State University-Pueblo, Pueblo, CO 81001 USA
| | - J A Turner
- Department of Biology, Colorado State University-Pueblo, Pueblo, CO 81001 USA
| | - B D Vanden Heuvel
- Department of Biology, Colorado State University-Pueblo, Pueblo, CO 81001 USA
| |
Collapse
|
47
|
Donovan PM, Blum JD, Singer MB, Marvin-DiPasquale M, Tsui MTK. Isotopic Composition of Inorganic Mercury and Methylmercury Downstream of a Historical Gold Mining Region. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:1691-702. [PMID: 26789018 DOI: 10.1021/acs.est.5b04413] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We measured total mercury (THg) and monomethyl mercury (MMHg) concentrations and mercury (Hg) isotopic compositions in sediment and aquatic organisms from the Yuba River (California, USA) to identify Hg sources and biogeochemical transformations downstream of a historical gold mining region. Sediment THg concentrations and δ(202)Hg decreased from the upper Yuba Fan to the lower Yuba Fan and the Feather River. These results are consistent with the release of Hg during gold mining followed by downstream mixing and dilution. The Hg isotopic composition of Yuba Fan sediment (δ(202)Hg = -0.38 ± 0.17‰ and Δ(199)Hg = 0.04 ± 0.03‰; mean ± 1 SD, n = 7) provides a fingerprint of inorganic Hg (IHg) that could be methylated locally or after transport downstream. The isotopic composition of MMHg in the Yuba River food web was estimated using biota with a range of %MMHg (the percent of THg present as MMHg) and compared to IHg in sediment, algae, and the food web. The estimated δ(202)Hg of MMHg prior to photodegradation (-1.29 to -1.07‰) was lower than that of IHg and we suggest this is due to mass-dependent fractionation (MDF) of up to -0.9‰ between IHg and MMHg. This result is in contrast to net positive MDF (+0.4 to +0.8‰) previously observed in lakes, estuaries, coastal oceans, and forests. We hypothesize that this unique relationship could be due to differences in the extent or pathway of biotic MMHg degradation in stream environments.
Collapse
Affiliation(s)
- Patrick M Donovan
- Department of Earth and Environmental Sciences, University of Michigan , 1100 N. University Avenue, Ann Arbor, Michigan 48109, United States
| | - Joel D Blum
- Department of Earth and Environmental Sciences, University of Michigan , 1100 N. University Avenue, Ann Arbor, Michigan 48109, United States
| | - Michael Bliss Singer
- Department of Earth and Environmental Sciences, University of St Andrews , North Street, St Andrews, KY16 9AL U.K
- Earth Research Institute, University of California Santa Barbara , Santa Barbara, California 93106 United States
| | | | - Martin T K Tsui
- Department of Biology, University of North Carolina at Greensboro , Greensboro, North Carolina 27402, United States
| |
Collapse
|
48
|
Hoggarth CGJ, Hall BD, Mitchell CPJ. Mercury methylation in high and low-sulphate impacted wetland ponds within the prairie pothole region of North America. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2015; 205:269-277. [PMID: 26099458 DOI: 10.1016/j.envpol.2015.05.046] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 04/21/2015] [Accepted: 05/21/2015] [Indexed: 06/04/2023]
Abstract
Using enriched stable (201)Hg injections into intact sediment cores, we provide the first reported Hg methylation potential rate constants (km) in prairie wetland ponds (0.016-0.17 d(-1)). Our km values were similar to other freshwater wetlands and did not differ in ponds categorized with high compared to low surface water concentrations of sulphate. Sites with high sulphate had higher proportions of methylmercury (MeHg) in sediment (2.9 ± 1.6% vs. 1.0 ± 0.3%) and higher surface water MeHg concentrations (1.96 ± 1.90 ng L(-1)vs. 0.56 ± 0.55 ng L(-1)). Sediment-porewater partitioning coefficients were small, and likely due to high ionic activity. Our work suggests while km measurements are useful for understanding mercury cycling processes, they are less important than surface water MeHg concentrations for assessing MeHg risks to biota. Significant differences in MeHg concentrations between sites with high and low sulphate concentrations may also inform management decisions concerning wetland remediation and creation.
Collapse
Affiliation(s)
- Cameron G J Hoggarth
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
| | - Britt D Hall
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada.
| | - Carl P J Mitchell
- Department of Physical and Environmental Science, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
| |
Collapse
|
49
|
Walters DM, Rosi-Marshall E, Kennedy TA, Cross WF, Baxter CV. Mercury and selenium accumulation in the Colorado River food web, Grand Canyon, USA. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2015; 34:2385-2394. [PMID: 26287953 DOI: 10.1002/etc.3077] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 03/05/2015] [Accepted: 05/20/2015] [Indexed: 06/04/2023]
Abstract
Mercury (Hg) and selenium (Se) biomagnify in aquatic food webs and are toxic to fish and wildlife. The authors measured Hg and Se in organic matter, invertebrates, and fishes in the Colorado River food web at sites spanning 387 river km downstream of Glen Canyon Dam (AZ, USA). Concentrations were relatively high among sites compared with other large rivers (mean wet wt for 6 fishes was 0.17-1.59 μg g(-1) Hg and 1.35-2.65 μg g(-1) Se), but consistent longitudinal patterns in Hg or Se concentrations relative to the dam were lacking. Mercury increased (slope = 0.147) with δ(15) N, a metric of trophic position, indicating biomagnification similar to that observed in other freshwater systems. Organisms regularly exceeded exposure risk thresholds for wildlife and humans (6-100% and 56-100% of samples for Hg and Se, respectfully, among risk thresholds). In the Colorado River, Grand Canyon, Hg and Se concentrations pose exposure risks for fish, wildlife, and humans, and the findings of the present study add to a growing body of evidence showing that remote ecosystems are vulnerable to long-range transport and subsequent bioaccumulation of contaminants. Management of exposure risks in Grand Canyon will remain a challenge, as sources and transport mechanisms of Hg and Se extend far beyond park boundaries.
Collapse
Affiliation(s)
- David M Walters
- US Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, USA
| | | | - Theodore A Kennedy
- US Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, Flagstaff, Arizona, USA
| | - Wyatt F Cross
- Department of Ecology, Montana State University, Bozeman, Montana, USA
| | - Colden V Baxter
- Department of Biological Sciences, Idaho State University, Pocatello, Idaho, USA
| |
Collapse
|
50
|
Walters DM, Raikow DF, Hammerschmidt CR, Mehling MG, Kovach A, Oris JT. Methylmercury Bioaccumulation in Stream Food Webs Declines with Increasing Primary Production. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:7762-7769. [PMID: 26018982 DOI: 10.1021/acs.est.5b00911] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Opposing hypotheses posit that increasing primary productivity should result in either greater or lesser contaminant accumulation in stream food webs. We conducted an experiment to evaluate primary productivity effects on MeHg accumulation in stream consumers. We varied light for 16 artificial streams creating a productivity gradient (oxygen production =0.048-0.71 mg O2 L(-1) d(-1)) among streams. Two-level food webs were established consisting of phytoplankton/filter feeding clam, periphyton/grazing snail, and leaves/shredding amphipod (Hyalella azteca). Phytoplankton and periphyton biomass, along with MeHg removal from the water column, increased significantly with productivity, but MeHg concentrations in these primary producers declined. Methylmercury concentrations in clams and snails also declined with productivity, and consumer concentrations were strongly correlated with MeHg concentrations in primary producers. Heterotroph biomass on leaves, MeHg in leaves, and MeHg in Hyalella were unrelated to stream productivity. Our results support the hypothesis that contaminant bioaccumulation declines with stream primary production via the mechanism of bloom dilution (MeHg burden per cell decreases in algal blooms), extending patterns of contaminant accumulation documented in lakes to lotic systems.
Collapse
Affiliation(s)
- David M Walters
- †U.S. Geological Survey, Fort Collins Science Center, 2150 Centre Avenue, Building C, Fort Collins, Colorado 80526, United States
| | - David F Raikow
- ‡U.S. Environmental Protection Agency, National Exposure Research Laboratory, Ecological Exposure Research Division, 26 West Martin Luther King Drive, Cincinnati, Ohio 45268, United States
| | | | - Molly G Mehling
- ∥Department of Biology, Miami University, Oxford, Ohio 45056, United States
| | - Amanda Kovach
- ∥Department of Biology, Miami University, Oxford, Ohio 45056, United States
| | - James T Oris
- ∥Department of Biology, Miami University, Oxford, Ohio 45056, United States
| |
Collapse
|