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Padalkar PP, Chakraborty P, Chennuri K, Jayachandran S, Sitlhou L, Nanajkar M, Tilvi S, Singh K. Molecular characteristics of sedimentary organic matter in controlling mercury (Hg) and elemental mercury (Hg 0) distribution in tropical estuarine sediments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 668:592-601. [PMID: 30856569 DOI: 10.1016/j.scitotenv.2019.02.353] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 02/20/2019] [Accepted: 02/22/2019] [Indexed: 06/09/2023]
Abstract
Sedimentary organic matter (SOM) plays an important role in hosting and reducing HgII in marine/estuarine sediment. This study provides a better understanding on the influence of nature of SOM, in regulating sedimentary mercury (Hg) and elemental mercury (Hg0) distribution, and speciation in the Zuari and Mandovi Estuaries that are representative of monsoon fed tropical estuaries, located in the central west coast of India. Salinity of the overlying water column controlled the physical and chemical characteristics of SOM in the estuarine systems. The high molecular weight (MW) SOM dominated at the mid and upstream (low salinity region) of the estuaries, whereas, the low MW SOM prevailed at the downstream (high salinity region). Sediment Hg showed more affinity towards the SOM of high MW. Increasing MW of SOM increased total sedimentary HgT in both the estuaries. SOM with low MW in the estuarine sediment displayed a negative relationship with the sediment Hg concentration. Distribution of Hg0 concentration in the estuarine sediment suggests that reduction of HgII in presence low MW SOM was a dominant process. It was also found that distribution and speciation of Hg0 in the estuarine sediment depends on the quantity, quality of the SOM, and the total sediment Hg loading. This study demonstrated that the competition between Hg-SOM complexation and HgII reduction by SOM controls HgII/Hg0 distribution in tropical estuarine sediment systems.
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Affiliation(s)
- Prasad P Padalkar
- Geological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India
| | - Parthasarathi Chakraborty
- Geological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India; Centre for Oceans, Rivers, Atmosphere and Land Sciences, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India.
| | - Kartheek Chennuri
- Geological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India
| | - Saranya Jayachandran
- Geological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India
| | - Lamjahao Sitlhou
- Geological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India
| | - Mandar Nanajkar
- Business Development Group, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India
| | - Supriya Tilvi
- Chemical Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India
| | - Keisham Singh
- Chemical Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India
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Lee S, Roh Y, Kim KW. Influence of chloride ions on the reduction of mercury species in the presence of dissolved organic matter. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2019; 41:71-79. [PMID: 29761243 DOI: 10.1007/s10653-018-0121-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Accepted: 05/07/2018] [Indexed: 06/08/2023]
Abstract
Mercuric species, Hg(II), interacts strongly with dissolved organic matter (DOM) through the oxidation, reduction, and complexation that affect the fate, bioavailability, and cycling of mercury, Hg, in aquatic environments. Despite its importance, the reactions between Hg(II) and DOM have rarely been studied in the presence of different concentrations of chloride ions (Cl-) under anoxic conditions. Here, we report that the extent of Hg(II) reduction in the presence of the reduced DOM decreases with increasing Cl- concentrations. The rate constants of Hg(II) reduction ranged from 0.14 to 1.73 h-1 in the presence of Cl- and were lower than the rate constant (2.41 h-1) in the absence of Cl-. Using a thermodynamic model, we showed that stable Hg(II)-chloride complexes were formed in the presence of Cl-. We further examined that H(0) was oxidized to Hg(II) in the presence of the reduced DOM and Cl- under anoxic conditions, indicating that Hg(II) reduction is inhibited by the Hg(0) oxidation. Therefore, the Hg(II) reduction by the reduced DOM can be offset due to the Hg(II)-chloride complexation and Hg(0) oxidation in chloride-rich environments. These processes can significantly influence the speciation of Hg and have an important implication for the behavior of Hg under environmentally relevant concentrations.
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Affiliation(s)
- Seyong Lee
- Environmental Assessment Group, Korea Environment Institute (KEI), 370 Sicheong-daero, Sejong, 30147, Republic of Korea
- Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), Gwahak-ro, Yuseong-gu, Daejeon, 34132, Republic of Korea
| | - Younghee Roh
- Institute for Korean Regional Studies, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Kyoung-Woong Kim
- Faculty of Environmental Studies, Universiti Putra Malaysia (UPM), Serdang, Selangor Darul Ehsan, Malaysia.
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea.
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D’Sa EJ, Joshi I, Liu B. Galveston Bay and Coastal Ocean Optical-Geochemical Response to Hurricane Harvey From VIIRS Ocean Color. GEOPHYSICAL RESEARCH LETTERS 2018; 45:10579-10589. [PMID: 31031451 PMCID: PMC6474122 DOI: 10.1029/2018gl079954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 09/22/2018] [Accepted: 09/27/2018] [Indexed: 06/09/2023]
Abstract
Dissolved and particulate organic carbon, suspended particulate matter concentrations, and their optical proxies colored dissolved organic matter absorption and backscattering coefficients were studied in Galveston Bay, Texas, following the extreme flooding of Houston and surrounding areas due to Hurricane Harvey (25-29 August 2017) using field and ocean color observations. A three-step empirical-semianalytic algorithm for determination of colored dissolved organic matter absorption and backscattering coefficients revealed the dynamics of dissolved organic carbon and particle distribution from Visible and Infrared Imaging Radiometric Suite ocean color. Environmental drivers, especially floodwater discharge and winds, strongly influenced the spatiotemporal distribution of dissolved/particulate material in the bay and shelf waters following the hurricane passage. Over 10 days during/following the hurricane, ~25.2 × 106 kg C of total organic carbon and ~314.7 × 106 kg of suspended particulate matter were rapidly exported from Galveston Bay (representing ~0.65% and 0.27% of respective annual Mississippi River fluxes to the Gulf of Mexico), with potential for ecological impacts to shelf waters.
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Affiliation(s)
- Eurico J. D’Sa
- Department of Oceanography and Coastal SciencesLouisiana State University and Agricultural and Mechanical CollegeBaton RougeLAUSA
| | - Ishan Joshi
- Department of Oceanography and Coastal SciencesLouisiana State University and Agricultural and Mechanical CollegeBaton RougeLAUSA
| | - Bingqing Liu
- Department of Oceanography and Coastal SciencesLouisiana State University and Agricultural and Mechanical CollegeBaton RougeLAUSA
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Wang W, Wang WX. Phase partitioning of trace metals in a contaminated estuary influenced by industrial effluent discharge. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 214:35-44. [PMID: 27061473 DOI: 10.1016/j.envpol.2016.03.059] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 03/22/2016] [Accepted: 03/22/2016] [Indexed: 06/05/2023]
Abstract
Severe trace metal pollution due to industrial effluents releases was found in Jiulong River Estuary, Southern China. In this study, water samples were collected during effluent release events to study the dynamic changes of environmental conditions and metal partitioning among dissolved, particulate and colloidal phases controlled by estuarine mixing. Intermittent effluent discharges during low tide caused decreasing pH and dissolved oxygen, and induced numerous suspended particulate materials and dissolved organic carbon to the estuary. Different behaviors of Cu, Zn, Ni, Cr and Pb in the dissolved fraction against the conservative index salinity indicated different sources, e.g., dissolved Ni from the intermittent effluent. Although total metal concentrations increased markedly following effluent discharges, Cu, Zn, Cr, Pb were predominated by the particulate fraction. Enhanced adsorption onto particulates in the mixing process resulted in elevated partitioning coefficient (Kd) values for Cu and Zn, and the particle concentration effect was not obvious under such anthropogenic impacts. Colloidal proportion of these metals (especially Cu and Zn) showed positive correlations with dissolved or colloidal organic carbon, suggesting the metal-organic complexation. However, the calculated colloidal partitioning coefficients were relatively constant, indicating the excess binding capacity. Overall, the intermittent effluent discharge altered the particulate/dissolved and colloidal/soluble phase partitioning process and may further influence the bioavailability and potential toxicity to aquatic organisms.
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Affiliation(s)
- Wenhao Wang
- Environmental Science Program, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong, and HKUST Shenzhen Research Institute, Shenzhen 518057, China
| | - Wen-Xiong Wang
- Environmental Science Program, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong, and HKUST Shenzhen Research Institute, Shenzhen 518057, China.
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Guédron S, Devin S, Vignati DAL. Total and methylmercury partitioning between colloids and true solution: From case studies in sediment overlying and porewaters to a generalized model. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2016; 35:330-339. [PMID: 26241033 DOI: 10.1002/etc.3190] [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: 03/17/2015] [Revised: 04/26/2015] [Accepted: 07/29/2015] [Indexed: 06/04/2023]
Abstract
Tangential flow ultrafiltration was used to determine the partitioning of total mercury (THg) and monomethylmercury (MMHg) between colloids and true solution in sediment overlying and porewaters collected in Lake Geneva (Switzerland and France), Venice Lagoon (Italy), and Baihua Reservoir (China). Overlying water and porewater spanned different ranges of THg and MMHg concentrations, redox conditions, and salinity. Total Hg, MMHg, and dissolved organic carbon (DOC) concentrations were measured in filter-passing (<0.45 μm), colloidal (3 kDa-0.45 μm), and truly dissolved (<3 kDa) fractions. The percentages of filterable Hg and MMHg associated with colloids (arithmetic means ±1 standard deviation [SD]) were 29 ± 11% for THg (range, 4-60%) and 44 ± 17% for MMHg (range, 15-65%). Ultrafiltration DOC mass balances were often not satisfactory. However, this was apparently without consequences on THg/MMHg fractionation, suggesting that only a part of total DOC controlled THg/MMHg partitioning in overlying water and porewater. Linear relationships existed between filter passing and truly dissolved concentrations of THg and MMHg, suggesting that mechanisms controlling their partitioning are, at least partly, similar across aquatic systems. These linear relationships could be extended to data from published studies and ultrafilterable concentrations often could be predicted, within a factor of 2, from the measurement of filter-passing ones. The possibility to easily model THg/MMHg partitioning across aquatic systems will facilitate its consideration in general biogeochemical THg/MMHg models.
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Affiliation(s)
- Stéphane Guédron
- Institute F.-A. Forel, University of Geneva, Versoix, Switzerland
- Institut des Sciences de la Terre, Grenoble, France
| | - Simon Devin
- CNRS, Interdisciplinary Laboratory for Continental Environments, National Center for Scientific Research, Metz, France
- Interdisciplinary Laboratory for Continental Environments, Université de Lorraine, Metz, France
| | - Davide A L Vignati
- CNRS, Interdisciplinary Laboratory for Continental Environments, National Center for Scientific Research, Metz, France
- Interdisciplinary Laboratory for Continental Environments, Université de Lorraine, Metz, France
- Water Research Institute-National Research Council (IRSA-CNR), Brugherio, Italy
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Jang J, Kim H, Han S. Influence of microorganism content in suspended particles on the particle-water partitioning of mercury in semi-enclosed coastal waters. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 470-471:1558-1564. [PMID: 24120117 DOI: 10.1016/j.scitotenv.2013.08.097] [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: 05/08/2013] [Revised: 08/26/2013] [Accepted: 08/28/2013] [Indexed: 06/02/2023]
Abstract
It is known that particle scavenging of mercury (Hg) can be affected by the abundance of particulate organic matter in coastal waters. However, the role of living organic particles in Hg scavenging is not yet completely understood. In this study, we hypothesized that an abundance of living organic particles (i.e., phytoplankton and bacteria) would influence the particle-water partitioning of Hg in coastal waters. Surface seawater samples were collected from eight stations in Gwangyang Bay, Korea, in three seasons (November 2009, April 2010, and October 2010) for the determination of concentrations of suspended particulate matter (including chlorophyll-a and bacteria), and Hg in unfiltered and filtered waters. We found that more Hg partitioned toward particulate matter when phytoplankton biomass, indicated from the chlorophyll-a concentration in a particle, was higher. In the low algal season, when [chlorophyll-a]<0.6 μg L(-1), the bacterial number, instead of chlorophyll-a concentration in particle, showed a positive correlation with the particle-water partition coefficient of Hg. Overall, microbial abundance seems to play a critical role in particle scavenging of Hg in coastal water. Taking this result in light of Hg in pristine coastal zones, we predict that increases in algal biomass amplify the potential for algae to transfer Hg to marine food chains.
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Affiliation(s)
- Jiyi Jang
- School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea; Global Bioresources Research Center, Korea Institute of Ocean Science and Technology (KIOST), Ansan 426-744, Republic of Korea
| | - Hyunji Kim
- School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea
| | - Seunghee Han
- School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea.
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Zhu Y, Ma LQ, Dong X, Harris WG, Bonzongo JC, Han F. Ionic strength reduction and flow interruption enhanced colloid-facilitated Hg transport in contaminated soils. JOURNAL OF HAZARDOUS MATERIALS 2014; 264:286-292. [PMID: 24316802 DOI: 10.1016/j.jhazmat.2013.11.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 10/22/2013] [Accepted: 11/04/2013] [Indexed: 06/02/2023]
Abstract
The effects of ionic strength (IS) reduction (5-0.05mM) and flow interruption (FI, flow stopped for 7d) on colloid and Hg release in the leachate were examined in column experiment. Two Hg contaminated soils (13.9 and 146mg/kg) were used, with Hg concentrations in colloids being 2-4 times greater than bulk soils. Based on sequential extraction, Hg concentrations in organic matter (OM) fraction were the most abundant in soils (31-48%). Column leaching after IS reduction and FI released large amounts of colloidal Hg, accounting for 44-48% of released Hg. The highest colloidal Hg concentrations at 27.8 and 360μg/L were observed at ∼1 pore volume after FI. Concentration distribution of colloidal OM and colloidal Fe was similar to colloidal Hg in the leachate, showing peak concentrations after IS reduction and FI. Most of the released colloidal Hg was in OM fraction (37-53%), with some in Fe/Mn oxide fraction (11-19%). Based on composition of released colloids and Hg fractionation in soils and colloids, colloidal OM could serve as an important carrier for Hg transport in soils.
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Affiliation(s)
- Yingjia Zhu
- Soil and Water Science Department, University of Florida, Gainesville, FL 32611, USA
| | - Lena Q Ma
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 210046, China; Soil and Water Science Department, University of Florida, Gainesville, FL 32611, USA.
| | - Xiaoling Dong
- Soil and Water Science Department, University of Florida, Gainesville, FL 32611, USA
| | - Willie G Harris
- Soil and Water Science Department, University of Florida, Gainesville, FL 32611, USA
| | - J C Bonzongo
- Department of Environmental Engineering and Sciences, University of Florida, Gainesville, FL 32611, USA
| | - Fengxiang Han
- Department of Chemistry and Biochemistry, Jackson State University, MS 39217, USA
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Hsu-Kim H, Kucharzyk KH, Zhang T, Deshusses MA. Mechanisms regulating mercury bioavailability for methylating microorganisms in the aquatic environment: a critical review. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:2441-56. [PMID: 23384298 DOI: 10.1021/es304370g] [Citation(s) in RCA: 404] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Mercury is a potent neurotoxin for humans, particularly if the metal is in the form of methylmercury. Mercury is widely distributed in aquatic ecosystems as a result of anthropogenic activities and natural earth processes. A first step toward bioaccumulation of methylmercury in aquatic food webs is the methylation of inorganic forms of the metal, a process that is primarily mediated by anaerobic bacteria. In this Review, we evaluate the current state of knowledge regarding the mechanisms regulating microbial mercury methylation, including the speciation of mercury in environments where methylation occurs and the processes that control mercury bioavailability to these organisms. Methylmercury production rates are generally related to the presence and productivity of methylating bacteria and also the uptake of inorganic mercury to these microorganisms. Our understanding of the mechanisms behind methylation is limited due to fundamental questions related to the geochemical forms of mercury that persist in anoxic settings, the mode of uptake by methylating bacteria, and the biochemical pathway by which these microorganisms produce and degrade methylmercury. In anoxic sediments and water, the geochemical forms of mercury (and subsequent bioavailability) are largely governed by reactions between Hg(II), inorganic sulfides, and natural organic matter. These interactions result in a mixture of dissolved, nanoparticulate, and larger crystalline particles that cannot be adequately represented by conventional chemical equilibrium models for Hg bioavailability. We discuss recent advances in nanogeochemistry and environmental microbiology that can provide new tools and unique perspectives to help us solve the question of how microorganisms methylate mercury. An understanding of the factors that cause the production and degradation of methylmercury in the environment is ultimately needed to inform policy makers and develop long-term strategies for controlling mercury contamination.
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Affiliation(s)
- Heileen Hsu-Kim
- Department of Civil and Environmental Engineering, Duke University , 121 Hudson Hall, Box 90287, Durham, North Carolina 27708, USA.
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Harris R, Pollman C, Hutchinson D, Landing W, Axelrad D, Morey SL, Dukhovskoy D, Vijayaraghavan K. A screening model analysis of mercury sources, fate and bioaccumulation in the Gulf of Mexico. ENVIRONMENTAL RESEARCH 2012; 119:53-63. [PMID: 23102631 DOI: 10.1016/j.envres.2012.08.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 07/17/2012] [Accepted: 08/01/2012] [Indexed: 05/27/2023]
Abstract
A mass balance model of mercury (Hg) cycling and bioaccumulation was applied to the Gulf of Mexico (Gulf), coupled with outputs from hydrodynamic and atmospheric Hg deposition models. The dominant overall source of Hg to the Gulf is the Atlantic Ocean. Gulf waters do not mix fully however, resulting in predicted spatial differences in the relative importance of external Hg sources to Hg levels in water, sediments and biota. Direct atmospheric Hg deposition, riverine inputs, and Atlantic inputs were each predicted to be the most important source of Hg to at least one of the modeled regions in the Gulf. While incomplete, mixing of Gulf waters is predicted to be sufficient that fish Hg levels in any given location are affected by Hg entering other regions of the Gulf. This suggests that a Gulf-wide approach is warranted to reduce Hg loading and elevated Hg concentrations currently observed in some fish species. Basic data to characterize Hg concentrations and cycling in the Gulf are lacking but needed to adequately understand the relationship between Hg sources and fish Hg concentrations.
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Affiliation(s)
- Reed Harris
- Reed Harris Environmental Ltd., 180 Forestwood Drive, Oakville, Ontario L6J4E6, Canada.
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Babiarz C, Hoffmann S, Wieben A, Hurley J, Andren A, Shafer M, Armstrong D. Watershed and discharge influences on the phase distribution and tributary loading of total mercury and methylmercury into Lake Superior. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2012; 161:299-310. [PMID: 22019205 DOI: 10.1016/j.envpol.2011.09.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 09/27/2011] [Indexed: 05/20/2023]
Abstract
Knowledge of the partitioning and sources of mercury are important to understanding the human impact on mercury levels in Lake Superior wildlife. Fluvial fluxes of total mercury (Hg(T)) and methylmercury (MeHg) were compared to discharge and partitioning trends in 20 sub-basins having contrasting land uses and geological substrates. The annual tributary yield was correlated with watershed characteristics and scaled up to estimate the basin-wide loading. Tributaries with clay sediments and agricultural land use had the largest daily yields with maxima observed near the peak in water discharge. Roughly 42% of Hg(T) and 57% of MeHg was delivered in the colloidal phase. Tributary inputs, which are confined to near-shore zones of the lake, may be more important to the food-web than atmospheric sources. The annual basin-wide loading from tributaries was estimated to be 277 kg yr(-1) Hg(T) and 3.4 kg yr(-1) MeHg (5.5 and 0.07 mg km(-2) d(-1), respectively).
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Affiliation(s)
- Christopher Babiarz
- Environmental Chemistry and Technology Program, University of Wisconsin-Madison, 660 North Park Street, Madison, WI 53706-1484, USA.
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