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Fulke AB, Ratanpal S, Sonker S. Understanding heavy metal toxicity: Implications on human health, marine ecosystems and bioremediation strategies. MARINE POLLUTION BULLETIN 2024; 206:116707. [PMID: 39018825 DOI: 10.1016/j.marpolbul.2024.116707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Revised: 07/03/2024] [Accepted: 07/05/2024] [Indexed: 07/19/2024]
Abstract
Heavy metals are constituents of the natural environment and are of great importance to both natural and artificial processes. But in recent times the indiscriminate use of heavy metals especially for human purposes has caused an imbalance in natural geochemical cycles. This imbalance has caused contamination of heavy metals into natural resources and such as soil and a marine ecosystem. Long exposure and higher accumulation of given heavy metals are known to impose detrimental and even lethal effects on humans. Conventional remediation techniques of heavy metals provide good results but have negative side effects on surrounding environment. The role played by microbes in bioremediation of heavy metals is well reported in the literature and understanding the role of molecules in the process of metal accumulation its reduction and transformation into less hazardous state, has myriads of biotechnological implications for bioremediation of metal-contaminated sites. The current review presents the implications of heavy metals on human health and marine ecosystems, conventional methods of heavy metal removal and their side effects on the environment. Bioremediation approaches have been discussed as well in this review, proving to be a more sustainable and eco-friendly approach towards remediation of heavy metals.
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Affiliation(s)
- Abhay B Fulke
- Microbiology Division, CSIR-National Institute of Oceanography (CSIR-NIO), Regional Centre, Lokhandwala Road, Four Bungalows, Andheri (West), Mumbai 400053, Maharashtra, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
| | - Siddant Ratanpal
- Amity Institute of Biotechnology, Amity University Maharashtra, Mumbai 410206, India
| | - Swati Sonker
- Microbiology Division, CSIR-National Institute of Oceanography (CSIR-NIO), Regional Centre, Lokhandwala Road, Four Bungalows, Andheri (West), Mumbai 400053, Maharashtra, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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2
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Guo W, Liu M, Zhang Q, Deng Y, Chu Z, Qin H, Li Y, Liu YR, Zhang H, Zhang W, Tao S, Wang X. Warming-Induced Vegetation Greening May Aggravate Soil Mercury Levels Worldwide. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024. [PMID: 39140482 DOI: 10.1021/acs.est.4c01923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
Mercury, a neurotoxic substance, circulates globally, significantly stored in soils through atmospheric deposition and plant decay. Despite being deposited, mercury can be remobilized and released into the atmosphere and water, enhancing its global cycle. Recent research suggests that climate warming may amplify the remobilization of soil mercury, facilitating its incorporation into food webs that humans exploit. However, the potential geospatial feedback of soil mercury levels in response to warming remains unclear. By leveraging up-to-date soil measurements and observation-driven models, we determined the amount of mercury stored in global 0-100 cm soils to be 4.3 Tg (interquartile range: 2.5-6.3 Tg). Furthermore, our analysis indicates that warming likely aggravates global soil mercury levels, particularly in many temperate areas in East Asia, North Europe, and North America (>20 ng g-1 increase by 2100) due to warming-induced vegetation greening. Critically, observation-driven models raise the possibility that implementing ambitious mercury-emission-control schemes alone may be insufficient to counterbalance the positive feedback of soil mercury concentration, while process-based biogeochemical modeling demonstrates consistent patterns that reinforce this concern. These findings hold broad implications; for example, such feedback may catalyze mercury remobilization in land-ocean continuums and exacerbate human risks, stressing the necessity for continued reductions in greenhouse gas and mercury emissions.
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Affiliation(s)
- Wenzhe Guo
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Maodian Liu
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
- School of the Environment, Yale University, New Haven, Connecticut 06511, United States
| | - Qianru Zhang
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
- Nicholas School of the Environment, Duke University, Durham, North Carolina 27708, United States
| | - Yidan Deng
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Zhaohan Chu
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Hehao Qin
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Yangmingkai Li
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Yu-Rong Liu
- College of Resources and Environment and State Environmental Protection Key Laboratory of Soil Health and Green Remediation, Huazhong Agricultural University, Wuhan 430070, China
| | - Haoran Zhang
- The Bartlett School of Sustainable Construction, University College London, London WC1E 7HB, U.K
| | - Wei Zhang
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Shu Tao
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Xuejun Wang
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
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3
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Ci Z, Yin Y, Shen W, Chen B. Non-conservative mixing behaviors of mercury in subterranean estuary: Coupling effect of hydrological and biogeochemical processes and implications for rapidly changing world. WATER RESEARCH 2023; 244:120455. [PMID: 37572463 DOI: 10.1016/j.watres.2023.120455] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 08/04/2023] [Accepted: 08/05/2023] [Indexed: 08/14/2023]
Abstract
Coastal ecosystem is an important zone of mercury (Hg) storage and hotspot of neurotoxic methylmercury (MMHg) production and bioaccumulation. The releases of Hg from coastal aquifer or subterranean estuary (STE) via submarine groundwater discharge (SGD) to coastal waters provide an important source of Hg from land to seas. However, the transport and biogeochemical transformation of Hg in STEs are less quantified. In this study, we documented total Hg (THg) and MMHg dynamics in two distinct STEs (a sandflat at an open coast versus a mudflat at a bay) during two different seasons (December versus August) in the temperate coast of northern China, and further applied the salinity-based conservative mixing model (CMM) to quantify the coupling effect of hydrological and biogeochemical processes on STE Hg cycle. Our field data presented large variations of THg and MMHg concentrations and%MMHg/THg of groundwater and sediment in both STEs over time and space. The CMM results clearly displayed substantial divergences of dissolved THg and MMHg from salinity in groundwater between sites and seasons, and the concentration and percent deviations in the Hg-rich mudflat were significantly higher than those in the Hg-poor sandflat. Our findings indicate the non-conservative mixing behaviors of Hg along the groundwater flow paths of both STEs, and the Hg-rich intertidal zone could be hotspot for the production and source of dissolved THg and MMHg to coastal waters via SGD. Our results provide field evidence to highlight that the hydrological shifts and biogeochemical processes collectively drive complex transport and biogeochemical transformation of Hg in STEs. The non-conservative mixing behaviors of Hg in STEs also highlight that, for more accurately calculating SGD-derived Hg fluxes to coastal seas, we need to carefully select the groundwater zonation of STE to better represent the output endmember. Our findings also address that human activities and climate change will profoundly alter the Hg biogeochemical cycle and toxicology in global coastal aquifers.
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Affiliation(s)
- Zhijia Ci
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China.
| | - Yongguang Yin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Wenjie Shen
- School of Earth Sciences and Engineering, Sun Yat-sen University, Zhuhai 519082, China; Guangdong Key Laboratory of Geological Process and Mineral Resources Exploration, Zhuhai 519082, China
| | - Baowei Chen
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
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4
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Ci Z, Tang X, Shen W, Chen B. Coastal streams and sewage outfalls: Hot spots of mercury discharge, pollution and cycling in nearshore environments. MARINE POLLUTION BULLETIN 2023; 195:115536. [PMID: 37708606 DOI: 10.1016/j.marpolbul.2023.115536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 09/04/2023] [Accepted: 09/08/2023] [Indexed: 09/16/2023]
Abstract
The coastal streams (CSs) and sewage outfalls (SOs) are widely distributed and direct anthropogenic stress on global coastal ecosystems. However, the CS/SO-associated mercury (Hg) discharge, pollution and cycle in nearshore environment are less quantified. Here, we report that total Hg (THg) and methylmercury (MMHg) concentrations in waters of CSs (n = 8) and SOs (n = 15) of the northern China were ∼102 to 103 times of coastal surface waters and 10 to 102 times of major rivers in China and other regions. The CS/SO discharges resulted in the increase of total organic carbon (TOC) contents, THg and MMHg concentrations and TOC-normalized THg and MMHg concentrations in sediments of CS/SO-impacted coasts. The laboratory experiments further illustrated that the CS/SO-impacted sediments characterized with high potentials of dissolved THg and MMHg productions and releases. Our findings indicate that the layout optimization of SOs is able to reduce the Hg risk in coastal environment.
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Affiliation(s)
- Zhijia Ci
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China.
| | - Xiong Tang
- Guangdong Eco-Engineering Polytechnic, Guangzhou 510520, China
| | - Wenjie Shen
- School of Earth Sciences and Engineering, Sun Yat-sen University, Zhuhai 519082, China; Guangdong Key Laboratory of Geological Process and Mineral Resources Exploration, Zhuhai 519082, China
| | - Baowei Chen
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
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Vishnudattan NK, Tait DR, Nandan SB, Aravind EH, Babu DSS, Jayachandran PR. The seasonal distribution and pollution potential of dissolved heavy metals and nutrients in subterranean estuaries in southern India. MARINE POLLUTION BULLETIN 2023; 194:115339. [PMID: 37517279 DOI: 10.1016/j.marpolbul.2023.115339] [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: 12/07/2022] [Revised: 07/17/2023] [Accepted: 07/21/2023] [Indexed: 08/01/2023]
Abstract
In order to better understand the distribution pattern, pollution degree and the submarine groundwater discharge (SGD) of dissolved heavy metals, 15 subterranean estuaries (STEs) along southwest Indian coast were sampled over three contrasting seasons. The average concentration of metals were ranked as, pre-monsoon > monsoon > post-monsoon with 3 to 12-fold higher groundwater metal concentrations than the adjacent seawater. Average SGD derived essential metal fluxes were five times higher than the toxic metal fluxes of which Fe and Zn together contributed >90 %. Using the Single Factor Contamination Index, the majority of sites were minimally contaminated with only two sites indicating moderate ecological risk due to As. Higher fluxes of Fe, Cu and Zn were likely a result of rising anthropogenic activities. The SGD derived nutrient fluxes were an important source of DIP for primary production in coastal waters and represented 30 % and 44 % of the DIN and DIP inputs respectively.
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Affiliation(s)
- N K Vishnudattan
- Department of Marine Biology, Microbiology & Biochemistry, School of Marine Sciences, Cochin University of Science & Technology, Fine Arts Avenue, Cochin 682016, Kerala, India
| | - Douglas R Tait
- Faculty of Science and Engineering, Southern Cross University, Lismore, NSW 2480, Australia
| | - S Bijoy Nandan
- Department of Marine Biology, Microbiology & Biochemistry, School of Marine Sciences, Cochin University of Science & Technology, Fine Arts Avenue, Cochin 682016, Kerala, India.
| | - E H Aravind
- Department of Marine Biology, Microbiology & Biochemistry, School of Marine Sciences, Cochin University of Science & Technology, Fine Arts Avenue, Cochin 682016, Kerala, India
| | - D S Suresh Babu
- National Centre for Earth Sciences Studies, Akkulam, Thiruvananthapuram 695031, Kerala, India
| | - P R Jayachandran
- Applied Research Center for Environment and Marine Studies (ARC-EMS), Research Institute, King Fahd University of Petroleum & Minerals (KFUPM), Dhahran 31261, Saudi Arabia
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6
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Coomar P, Das K, Debnath P, Verma S, Das P, Biswas A, Mukherjee A. Arsenic enriched groundwater discharge to a tropical ocean: Understanding controls and processes. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 318:120838. [PMID: 36496069 DOI: 10.1016/j.envpol.2022.120838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 11/11/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
The role of submarine groundwater discharge (SGD) in transporting terrestrial-sourced arsenic (As) to the global oceans is not well documented. In the present study, executed on a coast adjoining the extensive groundwater As-contaminated Ganges river delta, we hypothesize that As-enriched groundwater discharges to the adjoining Bay of Bengal (BoB) through SGD flow paths. We conducted high-resolution, field-based investigations and thermodynamic modeling to understand the SGD-sourced As discharge and geochemical cycling of As and other redox-sensitive solutes along the discharge path under varying redox conditions and water sediment interactions. The As distribution and other solutes were measured in a series of multi-depth observation wells and sediment cores, extending from the high tide line (HTL) to 100 m toward the sea, for pre- and post-monsoon seasons. Results reveal the presence of a plume carrying up to 30 μg/L dissolved load of As toward the sea. Arsenic is associated with a plume of Fe and exhibits similar shore-perpendicular variability. Arsenic distribution and transport is controlled by the Fe-Mn redox cycle and influenced by terrestrial groundwater discharge. Field-observations and geochemical modeling demonstrate that Fe-hydroxide precipitates in the subterranean estuary and acts as an interim sink for As , which is eventually mobilized on alteration of geochemical conditions with the season. Fluctuating plume size can be attributed to seasonal variation in fresh groundwater input to the site. Estimates indicate up to 55mg/m2/d As is released to BoB from the site. Based on physicochemical observations this study demonstrates the yet to be studied SGD derived As cycles and the role of SGD dynamics in controlling the fate of redox-sensitive contaminants and their discharge into global oceans.
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Affiliation(s)
- Poulomee Coomar
- Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur, India
| | - Kousik Das
- Department of Environmental Science, SRM University-AP, Mangalagiri, Andhra Pradesh, India
| | - Palash Debnath
- Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur, India
| | - Swati Verma
- Geological Oceanography Division, Council of Scientific & Industrial Research- National Institute of Oceanography (NIO), Dona Paula, India
| | - Prerona Das
- Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur, India
| | - Ashis Biswas
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Abhijit Mukherjee
- Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur, India; School of Environmental Science and Engineering, Indian Institute of Technology, Kharagpur, India; Applied Policy Advisory to Hydrosciences Group, Indian Institute of Technology, Kharagpur, India.
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7
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Mohammadpour A, Emadi Z, Samaei MR, Ravindra K, Hosseini SM, Amin M, Samiei M, Mohammadi L, Khaksefidi R, Zarei AA, Motamed-Jahromi M, Mousavi Khaneghah A. The concentration of potentially toxic elements (PTEs) in drinking water from Shiraz, Iran: a health risk assessment of samples. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:23295-23311. [PMID: 36322352 PMCID: PMC9938828 DOI: 10.1007/s11356-022-23535-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 10/05/2022] [Indexed: 06/16/2023]
Abstract
The existence of potentially toxic elements (PTEs) in water bodies has posed a menace to human health. Thus, water resources should be protected from PTEs, and their effect on the exposed population should be investigated. In the present investigation, the concentrations of PTEs such as lead (Pb), mercury (Hg), manganese (Mn), and iron(Fe) in the drinking water of Shiraz, Iran, were determined for the first time. In addition, hazard quotient, hazard index, cancer risk, and sensitivity analysis were applied to estimate the noncarcinogenic and carcinogenic impacts of Pb, Hg, Mn, and Fe on exposed children and adults through ingestion. The mean concentrations (µg/L) of Pb, Hg, Mn, and Fe were 0.36, 0.32, 2.28, and 8.72, respectively, in winter and 0.50, 0.20, 0.55, and 10.36, respectively, in summer. The results displayed that Fe concentration was more than the other PTEs. PTE concentrations were lower than the standard values of the Environment Protection Agency and World Health Organization. Values of the degree of contamination and heavy metal pollution index for lead, mercury, manganese, and iron were significantly low (< 1) and excellent (< 50), respectively. Based on the Spearman rank correlation analysis, positive and negative relationships were observed in the present study. The observations of the health risk assessment demonstrated that mercury, lead, iron, and manganese had an acceptable level of noncarcinogenic harmful health risk in exposed children and adults (hazard quotients < 1 and hazard index < 1). The carcinogenic risk of lead was low (< E - 06), which can be neglected. Monte Carlo simulation showed that water intake rate and mercury concentration were the most critical parameters in the hazard index for children and adults. Lead concentration was also the most crucial factor in the cancer risk analysis. The results of the present study proved that the drinking water of Shiraz is safe and healthy and can be confidently consumed by people.
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Affiliation(s)
- Amin Mohammadpour
- Department of Environmental Health Engineering, School of Public Health, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Zahra Emadi
- Department of Environmental Health Engineering, School of Public Health, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Mohammad Reza Samaei
- Department of Environmental Health Engineering, School of Public Health, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Khaiwal Ravindra
- Department of Community Medicine & School of Public Health, Post Graduate Institute of Medical Education & Research (PGIMER), Chandigarh, 160012, India
| | - Seyedeh Masoumeh Hosseini
- Department of Public Health and Food Hygiene, School of Veterinary Medicine, Shiraz University, PO Box 1731, Shiraz, Postal code 71345, Iran
| | - Mohammad Amin
- Department of Mechanical Engineering, Shiraz University, Shiraz, Iran
| | - Mojtaba Samiei
- Department of Mechanical Engineering, Shiraz University, Shiraz, Iran
| | - Leili Mohammadi
- Environmental Health, Infectious Diseases and Tropical Medicine Research Center, Zahedan University of Medical Sciences, Zahedan, 9816743463, Iran
| | - Razyeh Khaksefidi
- Department of Environmental Health Engineering, School of Public Health, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Amin Allah Zarei
- Health Sciences Research Center, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran
| | - Mohadeseh Motamed-Jahromi
- Department of Medical-Surgical Nursing, Nursing School, Fasa University of Medical Sciences, Fasa, Iran
| | - Amin Mousavi Khaneghah
- Department of Fruit and Vegetable Product Technology, Prof. Wacław Dąbrowski Institute of Agricultural and Food Biotechnology - State Research Institute, 36 Rakowiecka St, 02-532, Warsaw, Poland.
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Sekar S, Perumal M, Roy PD, Ganapathy M, Senapathi V, Yong Chung S, Elzain HE, Duraisamy M, Kamaraj J. A review on global status of fresh and saline groundwater discharge into the ocean. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:915. [PMID: 36255565 DOI: 10.1007/s10661-022-10566-y] [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: 12/12/2021] [Accepted: 02/25/2022] [Indexed: 06/16/2023]
Abstract
Submarine groundwater discharge (SGD) is the groundwater flow from land to the sea across the seabed, and it includes both terrane freshwater and recirculated seawater in the sub-surface. This review (i) systematically evaluates findings of various quantification methodologies, (ii) examines the estimated SGD in scientific publications between 2000 and 2020, and (iii) quantitatively evaluates current situation of coastal zone management through the bibliometric analysis of research papers. Apart from enhancing the shortage of groundwater resources in coastal area, the SGD brings nutrients (nitrate and phosphate), toxic heavy metals, and organic compounds, and thus contaminate the seawater. Therefore, the improved understanding about location and quantity of global SGD is essential to conserve the coastal and ocean ecosystems.
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Affiliation(s)
- Selvam Sekar
- Department of Geology, V.O. Chidambaram College, Tuticorin, Tamil Nadu, India.
| | - Muthukumar Perumal
- Department of Geology, V.O. Chidambaram College, Tuticorin, Tamil Nadu, India
- Registration No: 19212232221045, Affiliated to Manonmaniam Sundranar University, Tirunelveli, Tamil Nadu, India
| | - Priyadarsi Debajyoti Roy
- Instituto de Geología, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, CP, Mexico City, 04510, Mexico
| | - Moorthy Ganapathy
- Department of Geology, V.O. Chidambaram College, Tuticorin, Tamil Nadu, India
| | | | - Sang Yong Chung
- Department of Earth & Environmental Sciences, Institute of Environmental Geosciences, Pukyong National University, Busan, 608-737, Korea
| | - Hussam Eldin Elzain
- Water Research Center, Sultan Qaboos University, Muscat, Oman, United Arab Emirates
| | - Manimaran Duraisamy
- Department of Geology, V.O. Chidambaram College, Tuticorin, Tamil Nadu, India
| | - Jesuraja Kamaraj
- Department of Geology, V.O. Chidambaram College, Tuticorin, Tamil Nadu, India
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Conrad SR, Santos IR, White SA, Woodrow RL, Sanders CJ. Cryptic night-time trace metal and metalloid contamination in an intensively cultivated coastal catchment. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 276:116685. [PMID: 33636558 DOI: 10.1016/j.envpol.2021.116685] [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: 10/02/2020] [Revised: 01/18/2021] [Accepted: 02/04/2021] [Indexed: 06/12/2023]
Abstract
Detailed, high resolution time-series observations were performed to investigate sources, diel cycling, natural attenuation, and loadings of dissolved trace metals/metalloids in a subtropical headwater stream draining intensive horticulture in Australia. A transect of ∼3 km away from the source (farms) showed >75% reduction in concentration and loads of most trace elements. Mercury and arsenic had elevated loads downstream relative to other elements. Hourly time-series sampling revealed elevated creek discharge at night, accompanied by elevated nickel, selenium, copper, and mercury loads. Inputs from groundwater or treated sewage used for irrigation within the catchment are likely sources. Groundwater bore and treated sewage samples were highly contaminated with either zinc, copper, or mercury. Comparisons of daily and hourly samples indicated common sampling strategies can underestimate horticultural contaminant loadings. Load estimates for mercury and copper derived from hourly samples were 1.6- to 7- fold greater than loads from daily sample data collected over 79 days with varying rainfall. These high contaminant concentrations and loads are of concern to food products receiving irrigation and protected waterbodies downstream.
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Affiliation(s)
- Stephen R Conrad
- National Marine Science Centre, Southern Cross University, 2 Bay Dr, Coffs Harbour, 2450, NSW, Australia.
| | - Isaac R Santos
- National Marine Science Centre, Southern Cross University, 2 Bay Dr, Coffs Harbour, 2450, NSW, Australia; Department of Marine Sciences, University of Gothenburg, Box 461, 40530, Göteborg, Sweden
| | - Shane A White
- National Marine Science Centre, Southern Cross University, 2 Bay Dr, Coffs Harbour, 2450, NSW, Australia
| | - Rebecca L Woodrow
- National Marine Science Centre, Southern Cross University, 2 Bay Dr, Coffs Harbour, 2450, NSW, Australia
| | - Christian J Sanders
- National Marine Science Centre, Southern Cross University, 2 Bay Dr, Coffs Harbour, 2450, NSW, Australia
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10
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Babu DSS, Khandekar A, Bhagat C, Singh A, Jain V, Verma M, Bansal BK, Kumar M. Evaluation, effect and utilization of submarine groundwater discharge for coastal population and ecosystem: A special emphasis on Indian coastline. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 277:111362. [PMID: 32949950 DOI: 10.1016/j.jenvman.2020.111362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/24/2020] [Accepted: 09/05/2020] [Indexed: 06/11/2023]
Abstract
Submarine groundwater discharge (SGD) is an important process driven by marine and terrestrial forces. Low tide affects SGD the most, therefore the ideal time to detect SGD is the low tide, especially during spring tide. Techniques to detect and quantify SGD along with the understanding of the related aquifer characteristics is discussed in this study. Scientific community across the world is realizing the importance of studying and mapping SGD because in the scenario of climate change, this part of the global hydrological cycle is an important process and is known to have a significant effect on the marine ecosystem due to nutrient and metal inputs around the region of discharge. Therefore, understanding the processes governing SGD becomes very important. In this review, various components and processes related to SGD (e.g. Submarine Groundwater Recharge, Deep Porewater Upwelling, Recirculated Saline Groundwater Discharge), along with detailed discussion on impacts of SGD for marine ecosystem is presented. Also, it highlights the future research direction and emphasis is put on more research to be done keeping in mind the changing climate and its impacts on SGD.
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Affiliation(s)
- D S Suresh Babu
- National Centre for Earth Sciences Studies, Akkulam, Thiruvananthapuram, 695 031, India
| | - Ashwini Khandekar
- Discipline of Earth Sciences, Indian Institute of Technology, Gandhinagar, 382355, India
| | - Chandrashekhar Bhagat
- Discipline of Civil Engineering, Indian Institute of Technology, Gandhinagar, 382355, India
| | - Ashwin Singh
- Discipline of Civil Engineering, Indian Institute of Technology, Gandhinagar, 382355, India
| | - Vikrant Jain
- Discipline of Earth Sciences, Indian Institute of Technology, Gandhinagar, 382355, India
| | - Mithila Verma
- Ministry of Earth Sciences (MoES), New Delhi, 110003, India
| | | | - Manish Kumar
- Discipline of Earth Sciences, Indian Institute of Technology, Gandhinagar, 382355, India.
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Shoham-Frider E, Gertner Y, Guy-Haim T, Herut B, Kress N, Shefer E, Silverman J. Legacy groundwater pollution as a source of mercury enrichment in marine food web, Haifa Bay, Israel. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 714:136711. [PMID: 31981872 DOI: 10.1016/j.scitotenv.2020.136711] [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: 09/23/2019] [Revised: 01/13/2020] [Accepted: 01/13/2020] [Indexed: 06/10/2023]
Abstract
Haifa Bay (HB), located along the northern Mediterranean shore of Israel was polluted with Hg from a chlor-alkali plant (ECI) and from the Qishon River industries, for decades. From the mid-1980s industrial Hg loads into HB decreased dramatically until their complete cessation in 2000. Consequently, concentrations in marine biota and sediments decreased almost to reference levels. However, during 2006-2014, an unexpected increase of total Hg (THg) concentrations was observed in three commercial fish species collected at northern HB (N.HB). To determine the cause of this increase, THg and methyl Hg (MeHg) were measured in seawater, coastal groundwater, suspended particulate matter, plankton, macroalgae, benthic fauna, and in marine and beach sediments. THg in groundwater and sediments from the vicinity of ECI were extremely high (up to 251 μg L-1 and 2200 ng g-1, respectively). MeHg concentrations in groundwater were low and constituted <0.1% of THg, except in the surf zone opposite the ECI, where MeHg constituted 0.2% of the THg. THg and MeHg concentrations were consistently higher in benthic biota and plankton from N.HB and northwards, compared to corresponding samples from southern HB (S.HB) and the reference site (RS). MeHg in bivalves and sponges from N.HB and SZ was higher than from S.HB and RS, despite having similar THg concentrations, which suggests a stronger source of MeHg in N.HB. Our findings suggest that the discharge into N.HB of Hg polluted groundwater under the ECI increased during the period 2006-2014. The Hg was assimilated by plankton or adsorbed onto inorganic particles, which were further ingested by benthic and pelagic consumers, as well as transported northward with the alongshore current. These findings demonstrate for the first time the potential of relic pollution in groundwater to increase heavy metal burdens in local marine food webs.
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Affiliation(s)
- E Shoham-Frider
- Israel Oceanographic and Limnological Research, The National Institute of Oceanography, Haifa 31080, Israel.
| | - Y Gertner
- Israel Oceanographic and Limnological Research, The National Institute of Oceanography, Haifa 31080, Israel
| | - T Guy-Haim
- Israel Oceanographic and Limnological Research, The National Institute of Oceanography, Haifa 31080, Israel
| | - B Herut
- Israel Oceanographic and Limnological Research, The National Institute of Oceanography, Haifa 31080, Israel
| | - N Kress
- Israel Oceanographic and Limnological Research, The National Institute of Oceanography, Haifa 31080, Israel
| | - E Shefer
- Israel Oceanographic and Limnological Research, The National Institute of Oceanography, Haifa 31080, Israel
| | - J Silverman
- Israel Oceanographic and Limnological Research, The National Institute of Oceanography, Haifa 31080, Israel
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12
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Bowman KL, Lamborg CH, Agather AM. A global perspective on mercury cycling in the ocean. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 710:136166. [PMID: 32050358 DOI: 10.1016/j.scitotenv.2019.136166] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/10/2019] [Accepted: 12/15/2019] [Indexed: 05/20/2023]
Abstract
Mercury (Hg) is a ubiquitous metal in the ocean that undergoes in situ chemical transformations in seawater and marine sediment. Most relevant to public health is the production of monomethyl-Hg, a neurotoxin to humans that accumulates in marine fish and mammals. Here we synthesize 30 years of Hg measurements in the ocean to discuss sources, sinks, and internal cycling of this toxic metal. Global-scale oceanographic survey programs (i.e. CLIVAR and GEOTRACES), refined protocols for clean sampling, and analytical advancements have produced over 200 high-resolution, full-depth profiles of total Hg, methylated Hg, and gaseous elemental Hg throughout the Atlantic, Pacific, Arctic, and Southern Oceans. Vertical maxima of methylated Hg were found in surface waters, near the subsurface chlorophyll maximum, and in low-oxygen thermocline waters. The greatest concentration of Hg in deep water was measured in Antarctic Bottom Water, and in newly formed Labrador Sea Water, Hg showed a decreasing trend over the past 20 years. Distribution of Hg in polar oceans was unique relative to lower latitudes with higher concentrations of total Hg near the surface and vertical trends of Hg speciation driven by water column stratification and seasonal ice cover. Global models of Hg in the ocean require a better understanding of biogeochemical controls on Hg speciation and improved accuracy of methylated Hg measurements within the international community.
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Affiliation(s)
- Katlin L Bowman
- Moss Landing Marine Laboratories, 8272 Moss Landing Road, Moss Landing, CA 95039, USA; University of California Santa Cruz, Ocean Sciences Department, 1156 High Street, Santa Cruz, CA 95064, USA.
| | - Carl H Lamborg
- University of California Santa Cruz, Ocean Sciences Department, 1156 High Street, Santa Cruz, CA 95064, USA.
| | - Alison M Agather
- National Oceanic and Atmospheric Administration, 1325 East West Highway, Silver Spring, MD 20910, USA.
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13
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Debure M, Grangeon S, Robinet JC, Madé B, Fernández AM, Lerouge C. Influence of soil redox state on mercury sorption and reduction capacity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 707:136069. [PMID: 31865071 DOI: 10.1016/j.scitotenv.2019.136069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 12/06/2019] [Accepted: 12/09/2019] [Indexed: 06/10/2023]
Abstract
We investigated the mechanisms of interactions between divalent aqueous Hg and rock samples originating from an outcropping rock formation, the Albian Tégulines Clay (France, Aube). Two solid samples collected at two different depths (7.7 and 21.2 m depth) in the rock formation were selected since, in situ, they had and were still experiencing contrasting redox conditions, and thus had different mineralogy with regards to the minerals containing redox-sensitive elements, in particular iron. The sample that was the closer to the surface was under oxidizing conditions and contained goethite and siderite, while the deeper one was under reducing conditions and had more siderite, together with pyrite and magnetite. The redox state of the samples was preserved throughout the present study by careful conditioning, preparation, and use them under O2-free conditions. The two samples had similar affinity for Hg, with a retention coefficient (RD) ranging between 102 and 106 mol·kg-1 when the aqueous Hg concentration ranged between 4.4 and 107 ng·L-1 with the lowest concentration for the highest RD. However, the mechanisms of interaction differed. In the oxidized sample, no change in Hg redox state was observed, and the retention was due to reversible adsorption on the mineral phases (including organic matter). In contrast, upon interaction with the deeper and reduced sample, Hg was not only adsorbed on the mineral phases, but part of it was also reduced to dissolve elemental Hg. This reduction was attributed to magnetite and siderite and highlights the influence of mineralogy on the geochemical cycle of Hg.
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Affiliation(s)
| | | | | | - Benoît Madé
- Andra, R&D Division, Transfer Migration Group, 92298 Châtenay-Malabry, France
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14
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Oyetibo GO, Miyauchi K, Suzuki H, Endo G. Bio-oxidation of elemental mercury during growth of mercury resistant yeasts in simulated hydrosphere. JOURNAL OF HAZARDOUS MATERIALS 2019; 373:243-249. [PMID: 30921575 DOI: 10.1016/j.jhazmat.2019.02.075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Accepted: 02/20/2019] [Indexed: 06/09/2023]
Abstract
Transformation of metallic mercury (Hg°) to mercuric ion (Hg2+) in hydrosphere is the entrance of mercury cycle in water environments and leads to toxicological impact of serious global concern. Two yeast strains of Yarrowia (Idd1 and Idd2) isolated from Hg-contaminated sediments were studied for their mediating role in Hg° dissolution and oxidation. Growth of the Yarrowia cells in Hg-free liquid medium, incubated for 5 d in closed air-tight systems containing Hg°, produced extracellular polymeric substances (EPS). Approximately 230 (±5.7) ng and 120 (±6.8) ng of the dissolved Hg° were oxidized to Hg2+ by the cultures of Idd1 and Idd2, respectively, 5 day post-inoculation. Transmission electron microscopy (TEM) and X-ray energy dispersive spectrophotometry (XEDS) analysis of the EPS and cell mass revealed the presence of extracellular Hg nanoparticles, presumably HgS, as an indication of EPS-Hg complexation that is useful for Hg° dissolution and its eventual oxidation to Hg2+ by the cells. Fourier transmission infra-red (FTIR) analyses of the EPS and cell-mass during Hg-oxidation revealed that amine and carbonyl groups were used by EPS for Hg complexation. Our findings provided information about mediatory role played by Yarrowia (Idd1 and Idd2) in hydrosphere in biogeochemical cycling of Hg.
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Affiliation(s)
- Ganiyu Oladunjoye Oyetibo
- Department of Civil and Environmental Engineering, Faculty of Engineering, Tohoku-Gakuin University, 1-13-1 Chuo, Tagajo, Miyagi 985-8537, Japan; Department of Microbiology, Faculty of Science, University of Lagos, Akoka, Yaba, Lagos, Nigeria.
| | - Keisuke Miyauchi
- Department of Civil and Environmental Engineering, Faculty of Engineering, Tohoku-Gakuin University, 1-13-1 Chuo, Tagajo, Miyagi 985-8537, Japan.
| | - Hitoshi Suzuki
- Department of Civil and Environmental Engineering, Faculty of Engineering, Tohoku-Gakuin University, 1-13-1 Chuo, Tagajo, Miyagi 985-8537, Japan.
| | - Ginro Endo
- Department of Civil and Environmental Engineering, Faculty of Engineering, Tohoku-Gakuin University, 1-13-1 Chuo, Tagajo, Miyagi 985-8537, Japan.
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15
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Hiller-Bittrolff K, Foreman K, Bulseco-McKim AN, Benoit J, Bowen JL. Effects of mercury addition on microbial community composition and nitrate removal inside permeable reactive barriers. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 242:797-806. [PMID: 30032076 DOI: 10.1016/j.envpol.2018.07.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 07/03/2018] [Accepted: 07/04/2018] [Indexed: 06/08/2023]
Abstract
Permeable reactive barriers (PRBs) remove nitrogen from groundwater by enhancing microbial denitrification. The PRBs consist of woodchips that provide carbon for denitrifiers, but these woodchips also support other anaerobic microbes, including sulfate-reducing bacteria. Some of these anaerobes have the ability to methylate inorganic mercury present in groundwater. Methylmercury is hazardous to human health, so it is essential to understand whether PRBs promote mercury methylation. We examined microbial communities and geochemistry in fresh water and sulfate-enriched PRB flow-through columns by spiking replicates of both treatments with mercuric chloride. We hypothesized that mercury addition could alter bacterial community composition to favor higher abundances of genera containing known methylating taxa and that the sulfate-rich columns would produce more methylmercury after mercury addition, due mainly to an increase in abundance of sulfate reducing bacteria (SRB). However, methylmercury output at the end of the experiment was not different from output at the beginning, due in part to coupled Hg methylation and demethylation. There was a transient reduction in nitrate removal after mercury addition in the sulfate enriched columns, but nitrate removal returned to initial rates after two weeks, demonstrating resilience of the denitrifying community. Since methylmercury output did not increase and nitrate removal was not permanently affected, PRBs could be a low cost approach to combat eutrophication.
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Affiliation(s)
- Kenly Hiller-Bittrolff
- University of Massachusetts Boston Biology Department, 100 Morrissey Blvd, Boston, MA, USA.
| | - Kenneth Foreman
- Marine Biological Laboratory, Ecosystems Center, 7 MBL Street, Woods Hole, MA, USA.
| | - Ashley N Bulseco-McKim
- Northeastern University, Department of Marine and Environmental Sciences, Marine Science Center, 430 Nahant Road, Nahant, MA, USA.
| | - Janina Benoit
- Wheaton College, Chemistry Department, 26 E Main Street, Norton, MA, USA.
| | - Jennifer L Bowen
- Northeastern University, Department of Marine and Environmental Sciences, Marine Science Center, 430 Nahant Road, Nahant, MA, USA.
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16
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Outridge PM, Mason RP, Wang F, Guerrero S, Heimbürger-Boavida LE. Updated Global and Oceanic Mercury Budgets for the United Nations Global Mercury Assessment 2018. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:11466-11477. [PMID: 30226054 DOI: 10.1021/acs.est.8b01246] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In support of international efforts to reduce mercury (Hg) exposure in humans and wildlife, this paper reviews the literature concerning global Hg emissions, cycling and fate, and presents revised global and oceanic Hg budgets for the 2018 United Nations Global Mercury Assessment. We assessed two competing scenarios about the impacts of 16th - late 19th century New World silver (Ag) mining, which may be the largest human source of atmospheric Hg in history. Consideration of Ag ore geochemistry, historical documents on Hg use, and comparison of the scenarios against atmospheric Hg patterns in environmental archives, strongly support a "low mining emission" scenario. Building upon this scenario and other published work, the revised global budget estimates human activities including recycled legacy emissions have increased current atmospheric Hg concentrations by about 450% above natural levels (prevailing before 1450 AD). Current anthropogenic emissions to air are 2.5 ± 0.5 kt/y. The increase in atmospheric Hg concentrations has driven a ∼ 300% average increase in deposition, and a 230% increase in surface marine waters. Deeper marine waters show increases of only 12-25%. The overall increase in Hg in surface organic soils (∼15%) is small due to the large mass of natural Hg already present from rock weathering, but this figure varies regionally. Specific research recommendations are made to reduce uncertainties, particularly through improved understanding of fundamental processes of the Hg cycle, and continued improvements in emissions inventories from large natural and anthropogenic sources.
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Affiliation(s)
- P M Outridge
- Geological Survey of Canada , Natural Resources Canada , 601 Booth St. , Ottawa , Ontario K1A 0E8 , Canada
- Center for Earth Observation Science and Department of Environment and Geography , University of Manitoba , Winnipeg , Manitoba R3T 2N2 , Canada
| | - R P Mason
- Department of Marine Sciences , University of Connecticut , 1080 Shennecossett Road , Groton , Connecticut 06340 , United States
| | - F Wang
- Center for Earth Observation Science and Department of Environment and Geography , University of Manitoba , Winnipeg , Manitoba R3T 2N2 , Canada
| | - S Guerrero
- Universidad Metropolitana, Autopista Caracas Guarenas , Caracas 1073 , Venezuela
| | - L E Heimbürger-Boavida
- Aix Marseille Université , CNRS/INSU, Université de Toulon, IRD, Mediterranean Institute of Oceanography (MIO) UM 110, 13288 , Marseille , France
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17
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Wang J, Liu Q, Chen J, Chen H, Lin H, Sun X. Total mercury flux and offshore transport via submarine groundwater discharge and coal-fired power plant in the Jiulong River estuary, China. MARINE POLLUTION BULLETIN 2018; 127:794-803. [PMID: 29042105 DOI: 10.1016/j.marpolbul.2017.09.064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/23/2017] [Accepted: 09/26/2017] [Indexed: 06/07/2023]
Abstract
A mass balance of total mercury (HgT, dissolved+particulate) is constructed for China's Jiulong River estuary based on measured HgT concentrations in the surface water, sediment, porewater, and groundwater for May, August, and November 2009, combined with data from the literature. The HgT mass budget results show that the dominant source (39-55%) is desulfurized seawater discharged from the Songyu coal-fired power plant. Submarine groundwater discharge (SGD)-derived HgT flux into the estuary is equivalent to 8-58% of the HgT input from the Jiulong River, which is remarkable when compared with SGD-derived HgT fluxes reported in coastal systems worldwide. Hence, SGD is a significant pathway for the transport of HgT into the Jiulong River estuary. The primary HgT sinks is export to the Taiwan Strait (53-88%), which has important environmental implications on the Hg cycling and marine ecosystems in marginal seas.
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Affiliation(s)
- Jigang Wang
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian 361102, China; Third Institute of Oceanography, State Oceanic Administration, Xiamen, Fujian 361005, China
| | - Qian Liu
- State Key Lab of Marine Environmental Science, Xiamen University, Xiamen, Fujian 361102, China.
| | - Jinmin Chen
- Third Institute of Oceanography, State Oceanic Administration, Xiamen, Fujian 361005, China
| | - Hongzhe Chen
- Third Institute of Oceanography, State Oceanic Administration, Xiamen, Fujian 361005, China
| | - Hui Lin
- Third Institute of Oceanography, State Oceanic Administration, Xiamen, Fujian 361005, China
| | - Xiuwu Sun
- Third Institute of Oceanography, State Oceanic Administration, Xiamen, Fujian 361005, China
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18
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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.
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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
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Hatje V, Attisano KK, de Souza MFL, Mazzilli B, de Oliveira J, de Araújo Mora T, Burnett WC. Applications of radon and radium isotopes to determine submarine groundwater discharge and flushing times in Todos os Santos Bay, Brazil. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 178-179:136-146. [PMID: 28822315 DOI: 10.1016/j.jenvrad.2017.08.004] [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: 05/01/2017] [Revised: 08/02/2017] [Accepted: 08/08/2017] [Indexed: 06/07/2023]
Abstract
Todos os Santos Bay (BTS) is the 2nd largest bay in Brazil and an important resource for the people of the State of Bahia. We made measurements of radon and radium in selected areas of the bay to evaluate if these tracers could provide estimates of submarine groundwater discharge (SGD) and flushing times of the Paraguaçu Estuary and BTS. We found that there were a few areas along the eastern and northeastern shorelines that displayed relatively high radon and low salinities, indicating possible sites of enhanced SGD. A time-series mooring over a tidal cycle at Marina do Bonfim showed a systematic enrichment of the short-lived radium isotopes 223Ra and 224Ra during the falling tide. Assuming that the elevated radium isotopes were related to SGD and using measured radium activities from a shallow well at the site, we estimated groundwater seepage at about 70 m3/day per unit width of shoreline. Extrapolating to an estimated total shoreline length provided a first approximation of total (fresh + saline) SGD into BTS of 300 m3/s, about 3 times the average river discharge into the bay. Just applying the shoreline lengths from areas identified with high radon and reduced salinity results in a lower SGD estimate of 20 m3/s. Flushing times of the Paraguaçu Estuary were estimated at about 3-4 days based on changing radium isotope ratios from low to high salinities. The flushing time for the entire BTS was also attempted using the same approach and resulted in a surprisingly low value of only 6-8 days. Although physical oceanographic models have proposed flushing times on the order of months, a simple tidal prism calculation provided results in the range of 4-7 days, consistent with the radium approach. Based on these initial results, we recommend a strategy for refining both SGD and flushing time estimates.
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Affiliation(s)
- Vanessa Hatje
- Centro Interdisciplinar de Energia e Ambiente, CIENAM, Universidade Federal da Bahia, Ondina, Salvador, Bahia, 40170-115, Brazil.
| | - Karina Kammer Attisano
- Instituto de Oceanografia, Universidade Federal do Rio Grande - FURG, Rio Grande, RS, Brazil
| | | | - Barbara Mazzilli
- Instituto de Pesquisas Energéticase Nucleares (IPEN), Av. Prof. Lineu Prestes, 2242, SãoPaulo, SP, 05508-900, Brazil
| | - Joselene de Oliveira
- Instituto de Pesquisas Energéticase Nucleares (IPEN), Av. Prof. Lineu Prestes, 2242, SãoPaulo, SP, 05508-900, Brazil
| | - Tamires de Araújo Mora
- Instituto de Pesquisas Energéticase Nucleares (IPEN), Av. Prof. Lineu Prestes, 2242, SãoPaulo, SP, 05508-900, Brazil
| | - William C Burnett
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32309, USA
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20
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Groundwater Discharge in the Arctic: A Review of Studies and Implications for Biogeochemistry. HYDROLOGY 2017. [DOI: 10.3390/hydrology4030041] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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21
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Charette MA, Lam PJ, Lohan MC, Kwon EY, Hatje V, Jeandel C, Shiller AM, Cutter GA, Thomas A, Boyd PW, Homoky WB, Milne A, Thomas H, Andersson PS, Porcelli D, Tanaka T, Geibert W, Dehairs F, Garcia-Orellana J. Coastal ocean and shelf-sea biogeochemical cycling of trace elements and isotopes: lessons learned from GEOTRACES. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2016; 374:20160076. [PMID: 29035267 PMCID: PMC5069537 DOI: 10.1098/rsta.2016.0076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/30/2016] [Indexed: 05/06/2023]
Abstract
Continental shelves and shelf seas play a central role in the global carbon cycle. However, their importance with respect to trace element and isotope (TEI) inputs to ocean basins is less well understood. Here, we present major findings on shelf TEI biogeochemistry from the GEOTRACES programme as well as a proof of concept for a new method to estimate shelf TEI fluxes. The case studies focus on advances in our understanding of TEI cycling in the Arctic, transformations within a major river estuary (Amazon), shelf sediment micronutrient fluxes and basin-scale estimates of submarine groundwater discharge. The proposed shelf flux tracer is 228-radium (T1/2 = 5.75 yr), which is continuously supplied to the shelf from coastal aquifers, sediment porewater exchange and rivers. Model-derived shelf 228Ra fluxes are combined with TEI/ 228Ra ratios to quantify ocean TEI fluxes from the western North Atlantic margin. The results from this new approach agree well with previous estimates for shelf Co, Fe, Mn and Zn inputs and exceed published estimates of atmospheric deposition by factors of approximately 3-23. Lastly, recommendations are made for additional GEOTRACES process studies and coastal margin-focused section cruises that will help refine the model and provide better insight on the mechanisms driving shelf-derived TEI fluxes to the ocean.This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.
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Affiliation(s)
- Matthew A Charette
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Phoebe J Lam
- Department of Ocean Sciences, University of California-Santa Cruz, Santa Cruz, CA 95064, USA
| | - Maeve C Lohan
- Ocean and Earth Science, National Oceanography Centre, University of Southampton, Southampton SO14 3ZH, UK
| | - Eun Young Kwon
- Research Institute of Oceanography, Seoul National University, Seoul 151-742, Korea
| | - Vanessa Hatje
- Centro Interdisciplinar de Energia e Ambiente, Inst. de Química, Universidade Federal da Bahia, Salvador 40170-115, Brazil
| | - Catherine Jeandel
- University of Toulouse/CNRS/UPS/IRD/CNES, Observatoire Midi-Pyrénées, Toulouse 31400, France
| | - Alan M Shiller
- Department of Marine Science, University of Southern Mississippi, Stennis Space Center, MS 39529, USA
| | - Gregory A Cutter
- Department of Ocean, Earth, and Atmospheric Sciences, Old Dominion University, Norfolk, VA 23529, USA
| | - Alex Thomas
- School of GeoSciences, University of Edinburgh, Edinburgh EH9 3FE, UK
| | - Philip W Boyd
- Institute of Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania 7005, Australia
| | - William B Homoky
- Department of Earth Sciences, University of Oxford, Oxford OX1 3AN, UK
| | - Angela Milne
- School of Geography, Earth and Environmental Sciences, Plymouth University, Plymouth PL4 8AA, UK
| | - Helmuth Thomas
- Department of Oceanography, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4R2
| | - Per S Andersson
- Department of Geosciences, Swedish Museum of Natural History, Stockholm 104 05, Sweden
| | - Don Porcelli
- Department of Earth Sciences, University of Oxford, Oxford OX1 3AN, UK
| | - Takahiro Tanaka
- Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa Chiba 277-8564, Japan
| | - Walter Geibert
- Marine Geochemistry Department, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Frank Dehairs
- Earth System Sciences and Analytical, Environmental and Geo-Chemistry, Vrije Universiteit Brussel, Brussels 1050, Belgium
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Gworek B, Bemowska-Kałabun O, Kijeńska M, Wrzosek-Jakubowska J. Mercury in Marine and Oceanic Waters-a Review. WATER, AIR, AND SOIL POLLUTION 2016; 227:371. [PMID: 27656005 PMCID: PMC5013138 DOI: 10.1007/s11270-016-3060-3] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 08/24/2016] [Indexed: 05/19/2023]
Abstract
Mercury contamination in water has been an issue to the environment and human health. In this article, mercury in marine and oceanic waters has been reviewed. In the aquatic environment, mercury occurs in many forms, which depend on the oxidation-reduction conditions. These forms have been briefly described in this article. Mercury concentrations in marine waters in the different parts of the world have been presented. In the relevant literature, two models describing the fate and behavior of mercury in saltwater reservoirs have been presented, a conceptual model which treats all the oceans as one ocean and the "ocean margin" model, providing that the ocean margins manifested themselves as the convergence of continents and oceans, covering such geological features, such as estuaries, inland seas, and the continental shelf. These two conceptual models have been summarized in the text. The mercury content in benthic sediments usually reflects is level in the water reservoir, particularly in reservoirs situated in contaminated areas (mines, metallurgical plants, chemically protected crops). The concentrations of mercury and its compounds determined in the sediments in surface waters in the different parts of the world have been presented. Due to the fact that the pollution caused by mercury is a serious threat for the marine environment, the short paragraph about mercury bioaccumulation in aquatic organisms has been included. The cited data demonstrated a large scatter of mercury contents both between the fish species and the water areas. Mathematical models, valuable tools which provide information about the possible responses of ecosystems, developed to simulate mercury emissions, both at a small scale, for local water reservoirs, and at a global scale, as well as to model mercury bioaccumulation in the chain web of aquatic systems have been described.
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Affiliation(s)
- Barbara Gworek
- Institute of Environmental Protection–National Research Institute, Warsaw, Poland
| | | | - Marta Kijeńska
- Institute of Environmental Protection–National Research Institute, Warsaw, Poland
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Liu M, Chen L, Wang X, Zhang W, Tong Y, Ou L, Xie H, Shen H, Ye X, Deng C, Wang H. Mercury Export from Mainland China to Adjacent Seas and Its Influence on the Marine Mercury Balance. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:6224-6232. [PMID: 27243109 DOI: 10.1021/acs.est.5b04999] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Exports from mainland China are a significant source of mercury (Hg) in the adjacent seas (Bohai Sea, Yellow Sea, East China Sea, and South China Sea) near China. A total of 240 ± 23 Mg was contributed in 2012 (30% from natural sources and 70% from anthropogenic sources), including Hg from rivers, industrial wastewater, domestic sewage, groundwater, nonpoint sources, and coastal erosion. Among the various sources, the Hg from rivers amounts to 160 ± 21 Mg and plays a dominant role. The Hg that is exported from mainland China increased from 1984 to 2013; the contributions from rivers, industrial wastewater, domestic sewage and groundwater increased, and the contributions from nonpoint sources and coastal erosion remained stable. A box model is constructed to simulate the mass balance of Hg in these seas and quantify the sources, sinks and Hg biogeochemical cycle in the seas. In total, 160 Mg of Hg was transported to the Pacific Ocean and other oceans from these seas through oceanic currents in 2012, which could have negative impacts on the marine ecosystem. A prediction of the changes in Hg exportation through 2030 shows that the impacts of terrestrial export might worsen without effective pollution reduction measures and that the Hg load in these seas will increase, especially in the seawater of the Bohai Sea, Yellow Sea, and East China Sea and in the sea margin sediments of the Bohai Sea and East China Sea.
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Affiliation(s)
- Maodian Liu
- Ministry of Education Laboratory of Earth Surface Process, College of Urban and Environmental Sciences, Peking University , Beijing 100871, China
| | - Long Chen
- Ministry of Education Laboratory of Earth Surface Process, College of Urban and Environmental Sciences, Peking University , Beijing 100871, China
| | - Xuejun Wang
- Ministry of Education Laboratory of Earth Surface Process, College of Urban and Environmental Sciences, Peking University , Beijing 100871, China
| | - Wei Zhang
- School of Environment and Natural Resources, Renmin University of China , Beijing 100872, China
| | - Yindong Tong
- School of Environmental Science and Engineering, Tianjin University , Tianjin 300072, China
| | - Langbo Ou
- Ministry of Education Laboratory of Earth Surface Process, College of Urban and Environmental Sciences, Peking University , Beijing 100871, China
| | - Han Xie
- Ministry of Education Laboratory of Earth Surface Process, College of Urban and Environmental Sciences, Peking University , Beijing 100871, China
| | - Huizhong Shen
- Ministry of Education Laboratory of Earth Surface Process, College of Urban and Environmental Sciences, Peking University , Beijing 100871, China
| | - Xuejie Ye
- Ministry of Education Laboratory of Earth Surface Process, College of Urban and Environmental Sciences, Peking University , Beijing 100871, China
| | - Chunyan Deng
- Ministry of Education Laboratory of Earth Surface Process, College of Urban and Environmental Sciences, Peking University , Beijing 100871, China
| | - Huanhuan Wang
- Ministry of Education Laboratory of Earth Surface Process, College of Urban and Environmental Sciences, Peking University , Beijing 100871, China
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Ng K, Szabo Z, Reilly PA, Barringer JL, Smalling KL. An assessment of mercury in estuarine sediment and tissue in Southern New Jersey using public domain data. MARINE POLLUTION BULLETIN 2016; 107:22-35. [PMID: 27158049 DOI: 10.1016/j.marpolbul.2016.04.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 03/14/2016] [Accepted: 04/14/2016] [Indexed: 06/05/2023]
Abstract
Mercury (Hg) is considered a contaminant of global concern for coastal environments due to its toxicity, widespread occurrence in sediment, and bioaccumulation in tissue. Coastal New Jersey, USA, is characterized by shallow bays and wetlands that provide critical habitat for wildlife but share space with expanding urban landscapes. This study was designed as an assessment of the magnitude and distribution of Hg in coastal New Jersey sediments and critical species using publicly available data to highlight potential data gaps. Mercury concentrations in estuary sediments can exceed 2μg/g and correlate with concentrations of other metals. Based on existing data, the concentrations of Hg in mussels in southern New Jersey are comparable to those observed in other urbanized Atlantic Coast estuaries. Lack of methylmercury data for sediments, other media, and tissues are data gaps needing to be filled for a clearer understanding of the impacts of Hg inputs to the ecosystem.
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Affiliation(s)
- Kara Ng
- U.S. Geological Survey, New Jersey Water Science Center, Lawrenceville, NJ 08648, United States; The City College of New York, The Graduate Center, Ph.D. Program in Chemistry, New York, NY 10016, United States; The City College of New York, Division of Science, Department of Chemistry and Biochemistry, New York, NY 10031, United States
| | - Zoltan Szabo
- U.S. Geological Survey, New Jersey Water Science Center, Lawrenceville, NJ 08648, United States.
| | - Pamela A Reilly
- U.S. Geological Survey, New Jersey Water Science Center, Lawrenceville, NJ 08648, United States
| | - Julia L Barringer
- U.S. Geological Survey, New Jersey Water Science Center, Lawrenceville, NJ 08648, United States
| | - Kelly L Smalling
- U.S. Geological Survey, New Jersey Water Science Center, Lawrenceville, NJ 08648, United States
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25
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de Sieyes NR, Russell TL, Brown KI, Mohanty SK, Boehm AB. Transport of enterococci and F+ coliphage through the saturated zone of the beach aquifer. JOURNAL OF WATER AND HEALTH 2016; 14:26-38. [PMID: 26837827 DOI: 10.2166/wh.2015.290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Coastal groundwater has been implicated as a source of microbial pollution to recreational beaches. However, there is little work investigating the transport of fecal microbes through beach aquifers where waters of variable salinity are present. In this study, the potential for fecal indicator organisms enterococci (ENT) and F+ coliphage to be transported through marine beach aquifers was investigated. Native sediment and groundwaters were collected from the fresh and saline sections of the subterranean estuary at three beaches along the California coast where coastal communities utilize septic systems for wastewater treatment. Groundwaters were seeded with sewage and removal of F+ coliphage and ENT by the sediments during saturated flow was tested in laboratory column experiments. Removal varied significantly between beach and organism. F+ coliphage was removed to a greater extent than ENT, and removal was greater in saline sediments and groundwater than fresh. At one of the three beaches, a field experiment was conducted to investigate the attenuation of F+ coliphage and ENT down gradient of a septic leach field. ENT were detected up to 24 m from the leach field. The column study and field observations together suggest ENT can be mobile within native aquifer sediments and groundwater under certain conditions.
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Affiliation(s)
- Nicholas R de Sieyes
- Environmental and Water Studies, Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, 94305 USA E-mail:
| | - Todd L Russell
- Environmental and Water Studies, Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, 94305 USA E-mail:
| | - Kendra I Brown
- Environmental and Water Studies, Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, 94305 USA E-mail:
| | - Sanjay K Mohanty
- Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, PA, USA 19104
| | - Alexandria B Boehm
- Environmental and Water Studies, Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, 94305 USA E-mail:
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de Souza Machado AA, Spencer K, Kloas W, Toffolon M, Zarfl C. Metal fate and effects in estuaries: A review and conceptual model for better understanding of toxicity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 541:268-281. [PMID: 26410702 DOI: 10.1016/j.scitotenv.2015.09.045] [Citation(s) in RCA: 156] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 09/09/2015] [Accepted: 09/09/2015] [Indexed: 05/12/2023]
Abstract
Metal pollution is a global problem in estuaries due to the legacy of historic contamination and currently increasing metal emissions. However, the establishment of water and sediment standards or management actions in brackish systems has been difficult because of the inherent transdisciplinary nature of estuarine processes. According to the European Commission, integrative comprehension of fate and effects of contaminants in different compartments of these transitional environments (estuarine sediment, water, biota) is still required to better establish, assess and monitor the good ecological status targeted by the Water Framework Directive. Thus, the present study proposes a holistic overview and conceptual model for the environmental fate of metals and their toxicity effects on aquatic organisms in estuaries. This includes the analysis and integration of biogeochemical processes and parameters, metal chemistry and organism physiology. Sources of particulate and dissolved metal, hydrodynamics, water chemistry, and mechanisms of toxicity are discussed jointly in a multidisciplinary manner. It is also hypothesized how these different drivers of metal behaviour might interact and affect metal concentrations in diverse media, and the knowledge gaps and remaining research challenges are pointed. Ultimately,estuarine physicochemical gradients, biogeochemical processes, and organism physiology are jointly coordinating the fate and potential effects of metals in estuaries, and both realistic model approaches and attempts.
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Affiliation(s)
- Anderson Abel de Souza Machado
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587 Berlin, Germany; Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, Altensteinstraße 6, 14195 Berlin, Germany; School of Geography, Queen Mary University of London, Mile End Road, London E1 4N, UK.
| | - Kate Spencer
- School of Geography, Queen Mary University of London, Mile End Road, London E1 4N, UK
| | - Werner Kloas
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587 Berlin, Germany; Faculty of Mathematics and Natural Sciences I, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany
| | - Marco Toffolon
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, Via Mesiano 77, 38123 Trento, Italy
| | - Christiane Zarfl
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587 Berlin, Germany; Center for Applied Geosciences, Eberhard Karls Universität Tübingen, Hölderlinstr 12, 72074 Tübingen, Germany
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Mercury Reduction and Methyl Mercury Degradation by the Soil Bacterium Xanthobacter autotrophicus Py2. Appl Environ Microbiol 2015; 81:7833-8. [PMID: 26341208 DOI: 10.1128/aem.01982-15] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 08/30/2015] [Indexed: 11/20/2022] Open
Abstract
Two previously uncharacterized potential broad-spectrum mercury (Hg) resistance operons (mer) are present on the chromosome of the soil Alphaproteobacteria Xanthobacter autotrophicus Py2. These operons, mer1 and mer2, contain two features which are commonly found in mer operons in the genomes of soil and marine Alphaproteobacteria, but are not present in previously characterized mer operons: a gene for the mercuric reductase (MerA) that encodes an alkylmercury lyase domain typical of those found on the MerB protein, and the presence of an additional gene, which we are calling merK, with homology to glutathione reductase. Here, we demonstrate that Py2 is resistant to 0.2 μM inorganic mercury [Hg(II)] and 0.05 μM methylmercury (MeHg). Py2 is capable of converting MeHg and Hg(II) to elemental mercury [Hg(0)], and reduction of Hg(II) is induced by incubation in sub toxic concentrations of Hg(II). Transcription of the merA genes increased with Hg(II) treatment, and in both operons merK resides on the same polycistronic mRNA as merA. We propose the use of Py2 as a model system for studying the contribution of mer to Hg mobility in soil and marine ecosystems.
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Thayalakumaran T, Lenahan MJ, Bristow KL. Dissolved Organic Carbon in Groundwater Overlain by Irrigated Sugarcane. GROUND WATER 2015; 53:525-530. [PMID: 25213667 DOI: 10.1111/gwat.12258] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 07/09/2014] [Indexed: 06/03/2023]
Abstract
Elevated dissolved organic carbon (DOC) has been detected in groundwater beneath irrigated sugarcane on the Burdekin coastal plain of tropical northeast Australia. The maximum value of 82 mg/L is to our knowledge the highest DOC reported for groundwater beneath irrigated cropping systems. More than half of the groundwater sampled in January 2004 (n = 46) exhibited DOC concentrations greater than 30 mg/L. DOC was progressively lower in October 2004 and January 2005, with a total decrease greater than 90% indicating varying load(s) to the aquifer. It was hypothesized that the elevated DOC found in this groundwater system is sourced at or near the soil surface and supplied to the aquifer via vertical recharge following above average rainfall. Possible sources of DOC include organic-rich sugar mill by-products applied as fertilizer and/or sugarcane sap released during harvest. CFC-12 vertical flow rates supported the hypothesis that elevated DOC (>40 mg/L) in the groundwater results from recharge events in which annual precipitation exceeds 1500 mm/year (average = 960 mm/year). Occurrence of elevated DOC concentrations, absence of electron acceptors (O2 and NO3 (-) ) and both Fe(2+) and Mn(2+) greater than 1 mg/L in shallow groundwater suggest that the DOC compounds are chemically labile. The consequence of high concentrations of labile DOC may be positive (e.g., denitrification) or negative (e.g., enhanced metal mobility and biofouling), and highlights the need to account for a wider range of water quality parameters when considering the impacts of land use on the ecology of receiving waters and/or suitability of groundwater for irrigated agriculture.
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Affiliation(s)
- Thabo Thayalakumaran
- Cooperative Research Centre for Irrigation Futures and CSIRO Water for a Healthy Country National Research Flagship, CSIRO Land and Water, PMB Aitkenvale, Townsville, Queensland, 4814, Australia.
- Currently with Department of Environment and Primary Industries-Agriculture Research, 32 Lincoln Square Nth, Carlton, Vic, 3053, Australia.
| | - Matthew J Lenahan
- Cooperative Research Centre for Irrigation Futures and CSIRO Water for a Healthy Country National Research Flagship, CSIRO Land and Water, PMB Aitkenvale, Townsville, Queensland, 4814, Australia.
- Currently with AECOM, PO Box 5423, Townsville, Queensland, 4810, Australia.
| | - Keith L Bristow
- Cooperative Research Centre for Irrigation Futures and CSIRO Water for a Healthy Country National Research Flagship, CSIRO Land and Water, PMB Aitkenvale, Townsville, Queensland, 4814, Australia
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Submarine groundwater discharge as a major source of nutrients to the Mediterranean Sea. Proc Natl Acad Sci U S A 2015; 112:3926-30. [PMID: 25775554 DOI: 10.1073/pnas.1419049112] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Mediterranean Sea (MS) is a semienclosed basin that is considered one of the most oligotrophic seas in the world. In such an environment, inputs of allochthonous nutrients and micronutrients play an important role in sustaining primary productivity. Atmospheric deposition and riverine runoff have been traditionally considered the main external sources of nutrients to the MS, whereas the role of submarine groundwater discharge (SGD) has been largely ignored. However, given the large Mediterranean shore length relative to its surface area, SGD may be a major conveyor of dissolved compounds to the MS. Here, we used a (228)Ra mass balance to demonstrate that the total SGD contributes up to (0.3-4.8)⋅10(12) m(3) ⋅ y(-1) to the MS, which appears to be equal or larger by a factor of 16 to the riverine discharge. SGD is also a major source of dissolved inorganic nutrients to the MS, with median annual fluxes of 190⋅10(9), 0.7⋅10(9), and 110⋅10(9) mol for nitrogen, phosphorous, and silica, respectively, which are comparable to riverine and atmospheric inputs. This corroborates the profound implications that SGD may have for the biogeochemical cycles of the MS. Inputs of other dissolved compounds (e.g., iron, carbon) via SGD could also be significant and should be investigated.
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Chen CY, Borsuk ME, Bugge DM, Hollweg T, Balcom PH, Ward DM, Williams J, Mason RP. Benthic and pelagic pathways of methylmercury bioaccumulation in estuarine food webs of the northeast United States. PLoS One 2014; 9:e89305. [PMID: 24558491 PMCID: PMC3928433 DOI: 10.1371/journal.pone.0089305] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 01/17/2014] [Indexed: 11/18/2022] Open
Abstract
Methylmercury (MeHg) is a contaminant of global concern that bioaccumulates and bioamagnifies in marine food webs. Lower trophic level fauna are important conduits of MeHg from sediment and water to estuarine and coastal fish harvested for human consumption. However, the sources and pathways of MeHg to these coastal fisheries are poorly known particularly the potential for transfer of MeHg from the sediment to biotic compartments. Across a broad gradient of human land impacts, we analyzed MeHg concentrations in food webs at ten estuarine sites in the Northeast US (from the Hackensack Meadowlands, NJ to the Gulf of Maine). MeHg concentrations in water column particulate material, but not in sediments, were predictive of MeHg concentrations in fish (killifish and Atlantic silversides). Moreover, MeHg concentrations were higher in pelagic fauna than in benthic-feeding fauna suggesting that MeHg delivery to the water column from methylation sites from within or outside of the estuary may be an important driver of MeHg bioaccumulation in estuarine pelagic food webs. In contrast, bulk sediment MeHg concentrations were only predictive of concentrations of MeHg in the infaunal worms. Our results across a broad gradient of sites demonstrate that the pathways of MeHg to lower trophic level estuarine organisms are distinctly different between benthic deposit feeders and forage fish. Thus, even in systems with contaminated sediments, transfer of MeHg into estuarine food webs maybe driven more by the efficiency of processes that determine MeHg input and bioavailability in the water column.
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Affiliation(s)
- Celia Y. Chen
- Dartmouth College, Department of Biological Sciences, Hanover, New Hampshire, United States of America
- * E-mail:
| | - Mark E. Borsuk
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States of America
| | - Deenie M. Bugge
- Dartmouth College, Department of Biological Sciences, Hanover, New Hampshire, United States of America
| | - Terill Hollweg
- Stratus Consulting, Boulder, Colorado, United States of America
| | - Prentiss H. Balcom
- University of Connecticut, Department of Marine Science, Groton, Connecticut, United States of America
| | - Darren M. Ward
- Humboldt State University, Department of Fisheries Biology, Arcata, California, United States of America
| | - Jason Williams
- Washington State University, Department of Civil and Environmental Engineering, Pullman, Washington, United States of America
| | - Robert P. Mason
- University of Connecticut, Department of Marine Science, Groton, Connecticut, United States of America
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Lamborg CH, Kent DB, Swarr GJ, Munson KM, Kading T, O'Connor AE, Fairchild GM, Leblanc DR, Wiatrowski HA. Mercury speciation and mobilization in a wastewater-contaminated groundwater plume. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:13239-49. [PMID: 24187956 DOI: 10.1021/es402441d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We measured the concentration and speciation of mercury (Hg) in groundwater down-gradient from the site of wastewater infiltration beds operated by the Massachusetts Military Reservation, western Cape Cod, Massachusetts. Total mercury concentrations in oxic, mildly acidic, uncontaminated groundwater are 0.5-1 pM, and aquifer sediments have 0.5-1 ppb mercury. The plume of impacted groundwater created by the wastewater disposal is still evident, although inputs ceased in 1995, as indicated by anoxia extending at least 3 km down-gradient from the disposal site. Solutes indicative of a progression of anaerobic metabolisms are observed vertically and horizontally within the plume, with elevated nitrate concentrations and nitrate reduction surrounding a region with elevated iron concentrations indicating iron reduction. Mercury concentrations up to 800 pM were observed in shallow groundwater directly under the former infiltration beds, but concentrations decreased with depth and with distance down-gradient. Mercury speciation showed significant connections to the redox and metabolic state of the groundwater, with relatively little methylated Hg within the iron reducing sector of the plume, and dominance of this form within the higher nitrate/ammonium zone. Furthermore, substantial reduction of Hg(II) to Hg(0) within the core of the anoxic zone was observed when iron reduction was evident. These trends not only provide insight into the biogeochemical factors controlling the interplay of Hg species in natural waters, but also support hypotheses that anoxia and eutrophication in groundwater facilitate the mobilization of natural and anthropogenic Hg from watersheds/aquifers, which can be transported down-gradient to freshwaters and the coastal zone.
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Affiliation(s)
- Carl H Lamborg
- Woods Hole Oceanographic Institution , Department of Marine Chemistry and Geochemistry, Woods Hole, Massachusetts 02543, United States
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Zheng W, Lin H, Mann BF, Liang L, Gu B. Oxidation of dissolved elemental mercury by thiol compounds under anoxic conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:12827-34. [PMID: 24138581 DOI: 10.1021/es402697u] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Mercuric ion, Hg(2+), forms strong complexes with thiolate compounds that commonly dominate Hg(II) speciation in natural freshwater. However, reactions between dissolved aqueous elemental mercury (Hg(0)aq) and organic ligands in general, and thiol compounds in particular, are not well studied although these reactions likely affect Hg speciation and cycling in the environment. In this study, we compared the reaction rates between Hg(0)aq and a number of selected organic ligands with varying molecular structures and sulfur (S) oxidation states in dark, anoxic conditions to assess the role of these ligands in Hg(0)aq oxidation. Significant Hg(0)aq oxidation was observed with all thiols but not with ligands containing no S. Compounds with oxidized S (e.g., disulfide) exhibited little or no reactivity toward Hg(0)aq either at pH 7. The rate and extent of Hg(0)aq oxidation varied greatly depending on the chemical and structural properties of thiols, thiol/Hg ratios, and the presence or absence of electron acceptors. Smaller aliphatic thiols and higher thiol/Hg ratios resulted in higher Hg(0)aq oxidation rates than larger aromatic thiols at lower thiol/Hg ratios. The addition of electron acceptors (e.g., humic acid) also led to substantially increased Hg(0)aq oxidation. Our results suggest that thiol-induced oxidation of Hg(0)aq is important under anoxic conditions and can affect Hg redox transformation and bioavailability for microbial methylation.
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Affiliation(s)
- Wang Zheng
- Environmental Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States
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Szymczycha B, Miotk M, Pempkowiak J. Submarine Groundwater Discharge as a Source of Mercury in the Bay of Puck, the Southern Baltic Sea. WATER, AIR, AND SOIL POLLUTION 2013; 224:1542. [PMID: 23794765 PMCID: PMC3683146 DOI: 10.1007/s11270-013-1542-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 03/20/2013] [Indexed: 05/15/2023]
Abstract
Both groundwater flow and mercury concentrations in pore water and seawater were quantified in the groundwater seeping site of the Bay of Puck, southern Baltic Sea. Total dissolved mercury (HgTD) in pore water ranged from 0.51 to 4.90 ng l-1. Seawater samples were characterized by elevated HgTD concentrations, ranging from 4.41 to 6.37 ng l-1, while HgTD concentrations in groundwater samples ranged from 0.51 to 1.15 ng l-1. High HgTD concentrations in pore water of the uppermost sediment layers were attributed to seawater intrusion into the sediment. The relationship between HgTD concentrations and salinity of pore water was non-conservative, indicating removal of dissolved mercury upon mixing seawater with groundwater. The mechanism of dissolved mercury removal was further elucidated by examining its relationships with both dissolved organic matter, dissolved manganese (Mn II), and redox potential. The flux of HgTD to the Bay of Puck was estimated to be 18.9 ± 6.3 g year-1. The submarine groundwater discharge-derived mercury load is substantially smaller than atmospheric deposition and riverine discharge to the Bay of Puck. Thus, groundwater is a factor that dilutes the mercury concentrations in pore water and, as a result, dilutes the mercury concentrations in the water column.
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Affiliation(s)
- Beata Szymczycha
- Institute of Oceanology, Polish Academy of Sciences, ul. Powstancow Warszawy 55, 81712 Sopot, Poland
| | - Michał Miotk
- Institute of Oceanology, Polish Academy of Sciences, ul. Powstancow Warszawy 55, 81712 Sopot, Poland
| | - Janusz Pempkowiak
- Institute of Oceanology, Polish Academy of Sciences, ul. Powstancow Warszawy 55, 81712 Sopot, Poland
- Faculty of Construction and Environmental Engineering, Koszalin University of Technology, ul.Śniadeckich 2, 75453 Koszalin, Poland
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Rahman MM, Lee YG, Kim G, Lee K, Han S. Significance of submarine groundwater discharge in the coastal fluxes of mercury in Hampyeong Bay, Yellow Sea. CHEMOSPHERE 2013; 91:320-327. [PMID: 23276461 DOI: 10.1016/j.chemosphere.2012.11.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 11/23/2012] [Accepted: 11/24/2012] [Indexed: 06/01/2023]
Abstract
Submarine groundwater discharge (SGD) and various solutes released with SGD have received particular attention recently; however, understanding of the impact of SGD on trace metal fluxes in the coastal ocean is limited. To understand the contribution of SGD to the coastal Hg input, the Hg mass fluxes associated with SGD were estimated from Hampyeong Bay, a coastal embayment in the Yellow Sea. Hg concentrations in filtered groundwater and seawater ranged from 1.3 to 4.4pM and from 0.83 to 2.0pM, respectively, and Hg concentrations in unfiltered seawater ranged from 1.7 to 4.6pM. The Hg flux estimation showed that SGD was the prime input source of Hg in the bay (18±12molyr(-1)), contributing 65% of the total input. Atmospheric deposition was the second dominant source of Hg (8.5±2.7molyr(-1)), contributing 31% to the total input. The results of the current study suggest that SGD can be a significant source of Hg in estuarine/coastal systems; therefore, estimating the coastal mass budgets of Hg must include SGD as a prime source of Hg.
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Affiliation(s)
- Md Moklesur Rahman
- School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea
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Driscoll CT, Chen CY, Hammerschmidt CR, Mason RP, Gilmour CC, Sunderland EM, Greenfield BK, Buckman KL, Lamborg CH. Nutrient supply and mercury dynamics in marine ecosystems: a conceptual model. ENVIRONMENTAL RESEARCH 2012; 119:118-31. [PMID: 22749872 PMCID: PMC3646528 DOI: 10.1016/j.envres.2012.05.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 05/07/2012] [Accepted: 05/09/2012] [Indexed: 05/19/2023]
Abstract
There is increasing interest and concern over the impacts of mercury (Hg) inputs to marine ecosystems. One of the challenges in assessing these effects is that the cycling and trophic transfer of Hg are strongly linked to other contaminants and disturbances. In addition to Hg, a major problem facing coastal waters is the impacts of elevated nutrient, particularly nitrogen (N), inputs. Increases in nutrient loading alter coastal ecosystems in ways that should change the transport, transformations and fate of Hg, including increases in fixation of organic carbon and deposition to sediments, decreases in the redox status of sediments and changes in fish habitat. In this paper we present a conceptual model which suggests that increases in loading of reactive N to marine ecosystems might alter Hg dynamics, decreasing bioavailabilty and trophic transfer. This conceptual model is most applicable to coastal waters, but may also be relevant to the pelagic ocean. We present information from case studies that both support and challenge this conceptual model, including marine observations across a nutrient gradient; results of a nutrient-trophic transfer Hg model for pelagic and coastal ecosystems; observations of Hg species, and nutrients from coastal sediments in the northeastern U.S.; and an analysis of fish Hg concentrations in estuaries under different nutrient loadings. These case studies suggest that changes in nutrient loading can impact Hg dynamics in coastal and open ocean ecosystems. Unfortunately none of the case studies is comprehensive; each only addresses a portion of the conceptual model and has limitations. Nevertheless, our conceptual model has important management implications. Many estuaries near developed areas are impaired due to elevated nutrient inputs. Widespread efforts are underway to control N loading and restore coastal ecosystem function. An unintended consequence of nutrient control measures could be to exacerbate problems associated with Hg contamination. Additional focused research and monitoring are needed to critically examine the link between nutrient supply and Hg contamination of marine waters.
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Affiliation(s)
- Charles T. Driscoll
- Department of Civil and Environmental Engineering, Syracuse University, 151 Link Hall, Syracuse, NY 13244, USA, 315-443-3434 (phone), 315-443-1243 (fax)
| | - Celia Y. Chen
- Department of Biological Sciences, Dartmouth College, HB 6044, Hanover, NH 03755, USA
| | - Chad R. Hammerschmidt
- Department of Earth & Environmental Sciences, Wright State University, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA
| | - Robert P. Mason
- Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Road, Groton, CT 06340, USA
| | - Cynthia C. Gilmour
- Smithsonian Environmental Research Center, PO Box 28, Edgewater, MD 21037, USA
| | - Elsie M. Sunderland
- Harvard School of Public Health, Harvard University, 401 Park Drive, Boston, MA 02215, USA
| | - Ben K. Greenfield
- Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA 02543, USA
| | - Kate L. Buckman
- San Francisco Estuary Institute, 7770 Pardee Lane, Oakland, CA 94610, USA
| | - Carl H. Lamborg
- Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA 02543, USA
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Mason RP, Choi AL, Fitzgerald WF, Hammerschmidt CR, Lamborg CH, Soerensen AL, Sunderland EM. Mercury biogeochemical cycling in the ocean and policy implications. ENVIRONMENTAL RESEARCH 2012; 119:101-17. [PMID: 22559948 PMCID: PMC3427470 DOI: 10.1016/j.envres.2012.03.013] [Citation(s) in RCA: 260] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 03/09/2012] [Accepted: 03/26/2012] [Indexed: 05/20/2023]
Abstract
Anthropogenic activities have enriched mercury in the biosphere by at least a factor of three, leading to increases in total mercury (Hg) in the surface ocean. However, the impacts on ocean fish and associated trends in human exposure as a result of such changes are less clear. Here we review our understanding of global mass budgets for both inorganic and methylated Hg species in ocean seawater. We consider external inputs from atmospheric deposition and rivers as well as internal production of monomethylmercury (CH₃Hg) and dimethylmercury ((CH₃)₂Hg). Impacts of large-scale ocean circulation and vertical transport processes on Hg distribution throughout the water column and how this influences bioaccumulation into ocean food chains are also discussed. Our analysis suggests that while atmospheric deposition is the main source of inorganic Hg to open ocean systems, most of the CH₃Hg accumulating in ocean fish is derived from in situ production within the upper waters (<1000 m). An analysis of the available data suggests that concentrations in the various ocean basins are changing at different rates due to differences in atmospheric loading and that the deeper waters of the oceans are responding slowly to changes in atmospheric Hg inputs. Most biological exposures occur in the upper ocean and therefore should respond over years to decades to changes in atmospheric mercury inputs achieved by regulatory control strategies. Migratory pelagic fish such as tuna and swordfish are an important component of CH₃Hg exposure for many human populations and therefore any reduction in anthropogenic releases of Hg and associated deposition to the ocean will result in a decline in human exposure and risk.
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Affiliation(s)
- Robert P Mason
- Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Road, Groton, CT 06340, USA.
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Wang Y, Wiatrowski HA, John R, Lin CC, Young LY, Kerkhof LJ, Yee N, Barkay T. Impact of mercury on denitrification and denitrifying microbial communities in nitrate enrichments of subsurface sediments. Biodegradation 2012; 24:33-46. [PMID: 22678127 DOI: 10.1007/s10532-012-9555-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 05/04/2012] [Indexed: 10/28/2022]
Abstract
The contamination of groundwater with mercury (Hg) is an increasing problem worldwide. Yet, little is known about the interactions of Hg with microorganisms and their processes in subsurface environments. We tested the impact of Hg on denitrification in nitrate reducing enrichment cultures derived from subsurface sediments from the Oak Ridge Integrated Field Research Challenge site, where nitrate is a major contaminant and where bioremediation efforts are in progress. We observed an inverse relationship between Hg concentrations and onset and rates of denitrification in nitrate enrichment cultures containing between 53 and 1.1 μM of inorganic Hg; higher Hg concentrations increasingly extended the time to onset of denitrification and inhibited denitrification rates. Microbial community complexity, as indicated by terminal restriction fragment length polymorphism (tRFLP) analysis of the 16S rRNA genes, declined with increasing Hg concentrations; at the 312 nM Hg treatment, a single tRFLP peak was detected representing a culture of Bradyrhizobium sp. that possessed the merA gene indicating a potential for Hg reduction. A culture identified as Bradyrhizobium sp. strain FRC01 with an identical 16S rRNA sequence to that of the enriched peak in the tRFLP patterns, reduced Hg(II) to Hg(0) and carried merA whose amino acid sequence has 97 % identity to merA from the Proteobacteria and Firmicutes. This study demonstrates that in subsurface sediment incubations, Hg may inhibit denitrification and that inhibition may be alleviated when Hg resistant denitrifying Bradyrhizobium spp. detoxify Hg by its reduction to the volatile elemental form.
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Affiliation(s)
- Yanping Wang
- Department of Biochemistry and Microbiology, Rutgers University, 223C Lipman Hall, 76 Lipman Dr., New Brunswick, NJ 08901, USA.
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Ganguli PM, Conaway CH, Swarzenski PW, Izbicki JA, Flegal AR. Mercury speciation and transport via submarine groundwater discharge at a southern California coastal lagoon system. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:1480-1488. [PMID: 22283682 DOI: 10.1021/es202783u] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We measured total mercury (Hg(T)) and monomethylmercury (MMHg) concentrations in coastal groundwater and seawater over a range of tidal conditions near Malibu Lagoon, California, and used (222)Rn-derived estimates of submarine groundwater discharge (SGD) to assess the flux of mercury species to nearshore seawater. We infer a groundwater-seawater mixing scenario based on salinity and temperature trends and suggest that increased groundwater discharge to the ocean during low tide transported mercury offshore. Unfiltered Hg(T) (U-Hg(T)) concentrations in groundwater (2.2-5.9 pM) and seawater (3.3-5.2 pM) decreased during a falling tide, with groundwater U-Hg(T) concentrations typically lower than seawater concentrations. Despite the low Hg(T) in groundwater, bioaccumulative MMHg was produced in onshore sediment as evidenced by elevated MMHg concentrations in groundwater (0.2-1 pM) relative to seawater (∼0.1 pM) throughout most of the tidal cycle. During low tide, groundwater appeared to transport MMHg to the coast, resulting in a 5-fold increase in seawater MMHg (from 0.1 to 0.5 pM). Similarly, filtered Hg(T) (F-Hg(T)) concentrations in seawater increased approximately 7-fold during low tide (from 0.5 to 3.6 pM). These elevated seawater F-Hg(T) concentrations exceeded those in filtered and unfiltered groundwater during low tide, but were similar to seawater U-Hg(T) concentrations, suggesting that enhanced SGD altered mercury partitioning and/or solubilization dynamics in coastal waters. Finally, we estimate that the SGD Hg(T) and MMHg fluxes to seawater were 0.41 and 0.15 nmol m(-2) d(-1), respectively - comparable in magnitude to atmospheric and benthic fluxes in similar environments.
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Affiliation(s)
- P M Ganguli
- Earth and Planetary Sciences, University of California, Santa Cruz, California, United States.
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Lee YG, Rahman MM, Kim G, Han S. Mass balance of total mercury and monomethylmercury in coastal embayments of a volcanic island: significance of submarine groundwater discharge. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:9891-9900. [PMID: 21973173 DOI: 10.1021/es202093z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
To understand the contribution of submarine groundwater discharge (SGD) to the coastal mass budgets of Hg and monomethylmercury (MMHg), preliminary mass balance estimates were made for Hwasun and Bangdu Bays on Jeju Island, known to have large SGD due to the high permeability of the volcanic rocks. The mass balance results indicate that SGD is a main source of Hg in Hwasun Bay (23 ± 14 × 10(-2) mol yr(-1), 34%) and Bangdu Bay (23 ± 20 × 10(-2) mol yr(-1), 67%), although the contribution from atmospheric deposition was considerable (25% for Hwasun and 23% for Bangdu). MMHg was also discharged primarily from submarine groundwater at Hwasun (0.30 ± 0.17 × 10(-2) mol yr(-1), 55%) and Bangdu (0.65 ± 0.49 × 10(-2) mol yr(-1), 64%), which was higher than atmospheric deposition (6% for Hwasun and 2% for Bangdu) and sediment diffusion flux (5% for Hwasun and 3% for Bangdu). The overall mass balance results suggest that, although there are large spatial variations in SGD rates throughout the region, the coastal mass budgets of Hg and MMHg need to include SGD as well as atmospheric deposition and sediment diffusion as primary sources of Hg and MMHg.
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Affiliation(s)
- Yong-gu Lee
- School of Environment Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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Santos IR, de Weys J, Eyre BD. Groundwater or floodwater? Assessing the pathways of metal exports from a coastal acid sulfate soil catchment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:9641-9648. [PMID: 21967763 DOI: 10.1021/es202581h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Daily observations of dissolved aluminum, iron, and manganese in an estuary downstream of a coastal acid sulfate soil (CASS) catchment provided insights into how floods and submarine groundwater discharge drive wetland metal exports. Extremely high Al, Fe, and Mn concentrations (up to 40, 374, and 8 mg L(-1), respectively) were found in shallow acidic groundwaters from the Tuckean Swamp, Australia. Significant correlations between radon (a natural groundwater tracer) and metals in surface waters revealed that metal loads were driven primarily by groundwater discharge. Dissolved Fe, Mn, and Al loads during a 16-day flood triggered by a 213 mm rain event were respectively 80, 35, and 14% of the total surface water exports during the four months of observations. Counter clockwise hysteresis was observed for Fe and Mn in surface waters during the flood due to delayed groundwater inputs. Groundwater-derived Fe fluxes into artificial drains were 1 order of magnitude higher than total surface water exports, which is consistent with the known accumulation of monosulfidic black ooze within the wetland drains. Upscaling the Tuckean catchment export estimates yielded dissolved Fe fluxes from global acid sulfate soil catchments on the same order of magnitude of global river inputs into estuaries.
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Affiliation(s)
- Isaac R Santos
- Centre for Coastal Biogeochemistry, School of Environmental Science and Management, Southern Cross University , Lismore, NSW 2480, Australia.
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Abstract
SEAWAT, a U.S. Geological Survey groundwater flow and transport code, is increasingly used to model the effects of tidal motion on coastal aquifers. Different options are available to simulate tidal boundaries but no guidelines exist nor have comparisons been made to identify the most effective approach. We test seven methods to simulate a sloping beach and a tidal flat. The ocean is represented in one of the three ways: directly using a high hydraulic conductivity (high-K) zone and indirect simulation via specified head boundaries using either the General Head Boundary (GHB) or the new Periodic Boundary Condition (PBC) package. All beach models simulate similar water fluxes across the upland boundary and across the sediment-water interface although the ratio of intertidal to subtidal flow is different at low tide. Simulating a seepage face results in larger intertidal fluxes and influences near-shore heads and salinity. Major differences in flow occur in the tidal flat simulations. Because SEAWAT does not simulate unsaturated flow the water table only rises via flow through the saturated zone. This results in delayed propagation of the rising tidal signal inland. Inundation of the tidal flat is delayed as is flow into the aquifer across the flat. This is severe in the high-K and PBC models but mild in the GHB models. Results indicate that any of the tidal boundary options are fine if the ocean-aquifer interface is steep. However, as the slope of that interface decreases, the high-K and PBC approaches perform poorly and the GHB boundary is preferable.
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Affiliation(s)
- Ann E Mulligan
- Marine Policy Center, MS-41, Woods Hole Oceanographic Institution, Wood Hole, MA 02543, USA.
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42
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Rogers DR, Casciotti KL. Abundance and diversity of archaeal ammonia oxidizers in a coastal groundwater system. Appl Environ Microbiol 2010; 76:7938-48. [PMID: 20971859 PMCID: PMC3008261 DOI: 10.1128/aem.02056-09] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 10/18/2010] [Indexed: 11/20/2022] Open
Abstract
Nitrification, the microbially catalyzed oxidation of ammonia to nitrate, is a key process in the nitrogen cycle. Archaea have been implicated in the first part of the nitrification pathway (oxidation of ammonia to nitrite), but the ecology and physiology of these organisms remain largely unknown. This work describes two different populations of sediment-associated ammonia-oxidizing archaea (AOA) in a coastal groundwater system in Cape Cod, MA. Sequence analysis of the ammonia monooxygenase subunit A gene (amoA) shows that one population of putative AOA inhabits the upper meter of the sediment, where they may experience frequent ventilation, with tidally driven overtopping and infiltration of bay water supplying dissolved oxygen, ammonium, and perhaps organic carbon. A genetically distinct population occurs deeper in the sediment, in a mixing zone between a nitrate- and oxygen-rich freshwater zone and a reduced, ammonium-bearing saltwater wedge. Both of these AOA populations are coincident with increases in the abundance of group I crenarchaeota 16S rRNA gene copies.
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Affiliation(s)
- Daniel R Rogers
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA.
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Garcia-Orellana J, Cochran JK, Bokuniewicz H, Yang S, Beck AJ. Time-series sampling of 223Ra and 224Ra at the inlet to Great South Bay (New York): a strategy for characterizing the dominant terms in the Ra budget of the bay. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2010; 101:582-588. [PMID: 20106570 DOI: 10.1016/j.jenvrad.2009.12.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 12/16/2009] [Accepted: 12/24/2009] [Indexed: 05/28/2023]
Abstract
Ra isotopes are a powerful tool for quantifying the flux of submarine groundwater discharge (SGD) into the sea. Previous studies of 223Ra and 224Ra mass balances in coastal embayments have shown that the Ra balance is dominated by supply via SGD, exchange with the open ocean and radioactive decay. The current study shows that a single time series over a tidal cycle at the principal inlet to Great South Bay (NY, US) is sufficient to determine the net flux of Ra across the inlet, and also can be used to estimate the decay of short-lived Ra in the bay. Estimates of the net Ra flux obtained from a single tidal time-series by using three different approaches agree with those determined from a more time-consuming survey of Ra within the bay, and may represent a first step of estimating SGD in bays and coastal lagoons.
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Affiliation(s)
- J Garcia-Orellana
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794-5000, USA.
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Abstract
The exchange of groundwater between land and sea is a major component of the hydrological cycle. This exchange, called submarine groundwater discharge (SGD), is comprised of terrestrial water mixed with sea water that has infiltrated coastal aquifers. The composition of SGD differs from that predicted by simple mixing because biogeochemical reactions in the aquifer modify its chemistry. To emphasize the importance of mixing and chemical reaction, these coastal aquifers are called subterranean estuaries. Geologists recognize this mixing zone as a site of carbonate diagenesis and dolomite formation. Biologists have recognized that terrestrial inputs of nutrients to the coastal ocean may occur through subterranean processes. Further evidence of SGD comes from the distribution of chemical tracers in the coastal ocean. These tracers originate within coastal aquifers and reach the ocean through SGD. Tracer studies reveal that SGD provides globally important fluxes of nutrients, carbon, and metals to coastal waters.
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Affiliation(s)
- Willard S Moore
- Department of Earth and Ocean Sciences, University of South Carolina, Columbia, South Carolina 29208, USA.
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Black FJ, Paytan A, Knee KL, De Sieyes NR, Ganguli PM, Gray E, Flegal AR. Submarine groundwater discharge of total mercury and monomethylmercury to central California coastal waters. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:5652-5659. [PMID: 19731658 DOI: 10.1021/es900539c] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Fluxes of total mercury (Hg(T)) and monomethylmercury (MMHg) associated with submarine groundwater discharge (SGD) at two sites onthe central California coast were estimated by combining measurements of Hg(T) and MMHg in groundwater with the use of short-lived, naturally occurring radium isotopes as tracers of groundwater inputs. Concentrations of Hg(T) were relatively low, ranging from 1.2 to 28.3 pM in filtered groundwater, 0.8 to 11.6 pM in filtered surface waters, and 2.5 to 12.9 pM in unfiltered surface waters. Concentrations of MMHg ranged from < 0.04 to 3.1 pM in filtered groundwater, < 0.04 to 0.53 pM in filtered surface waters, and 0.07 to 1.2 pM in unfiltered surface waters. Multiple linear regression analysis identified significant (p < 0.05) positive correlations between dissolved groundwater concentrations of Hg(T) and those of NH4+ and SiO2, and between dissolved groundwater concentrations of MMHg and those of Hg(T) and NH4+. However, such relationships did not account for the majority of the variability in concentration data for either mercury species in groundwater. Fluxes of Hg(T) via SGD were estimated to be 250 +/- 160 nmol day m(-1) of shoreline at Stinson Beach and 3.0 +/- 2.0 nmol m(-2) day(-1) at Elkhorn Slough. These Hg(T) fluxes are substantially greater than net atmospheric inputs of Hg(T) reported for waters in nearby San Francisco Bay. Calculated fluxes of MMHg to coastal waters via SGD were 10 +/- 12 nmol day(-1) m(-1) of shoreline at Stinson Beach and 0.24 +/- 0.21 nmol m(-2) day at Elkhorn Slough. These MMHg fluxes are similar to benthic fluxes of MMHg out of surface sediments commonly reported for estuarine and coastal environments. Consequently, this work demonstrates that SGD is an important source of both Hg(T) and MMHg to coastal waters along the central California coast.
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Affiliation(s)
- Friank J Black
- WIGS Laboratory, Department of Environmental Toxicology, and Institute of Marine Sciences, University of California, Santa Cruz, California 95064, USA.
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Wiatrowski HA, Das S, Kukkadapu R, Ilton ES, Barkay T, Yee N. Reduction of Hg(II) to Hg(0) by magnetite. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:5307-13. [PMID: 19708358 DOI: 10.1021/es9003608] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Mercury (Hg) is a highly toxic element, and its contamination of groundwater presents a significant threat to terrestrial ecosystems. Understanding the geochemical processes that mediate mercury transformations in the subsurface is necessary to predict its fate and transport. In this study, we investigated the redox transformation of mercuric Hg (Hg[II]) in the presence of the Fe(II)/Fe(III) mixed valence iron oxide mineral magnetite. Kinetic and spectroscopic experiments were performed to elucidate reaction rates and mechanisms. The experimental data demonstrated that reaction of Hg(II) with magnetite resulted in the loss of Hg(II) and the formation of volatile elemental Hg (Hg[0]). Kinetic experiments showed that Hg(II) reduction occurred within minutes, with reaction rates increasing with increasing magnetite surface area (0.5 to 2 m2/L) and solution pH (4.8 to 6.7), and decreasing with increasing chloride concentration (10(-6) to 10(-2) mol/L). Mössbauer spectroscopic analysis of reacted magnetite samples revealed a decrease in Fe(II) content, corresponding to the oxidation of Fe(II) to Fe(III) in the magnetite structure. X-ray photoelectron spectroscopy detected the presence of Hg(II) on magnetite surfaces, implying that adsorption is involved in the electron transfer process. These results suggest that Hg(II) reaction with solid-phase Fe(II) is a kinetically favorable pathway for Hg(II) reduction in magnetite-hearing environmental systems.
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Affiliation(s)
- Heather A Wiatrowski
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, New Jersey, USA
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Jeffree RA, Oberhansli F, Teyssie JL. The accumulation of lead and mercury from seawater and their depuration by eggs of the spotted dogfish Scyliorhinus canicula (Chondrichthys). ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2008; 55:451-61. [PMID: 18214579 DOI: 10.1007/s00244-007-9103-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Accepted: 11/23/2007] [Indexed: 05/16/2023]
Abstract
Radiotracer experiments using (210)Pb and (203)Hg demonstrated that eggs of the spotted dogfish Scyliorhinus canicula absorbed lead and inorganic mercury directly from seawater over 21 days of experimental exposure, attaining total egg concentration factors (CFs) relative to water of approximately 400 for Pb and 180 for Hg, predominantly (> or =98%) due to their accumulation by the collagenous egg case. The rates of accumulation of both Pb and Hg by the total egg were significantly (P < 0.0001) reduced by its increasing age since parturition, whereas only the rate of depuration of Pb was reduced (P < 0.0001) with increasing age; these effects indicate a declining chemical reactivity of the egg case that may be due to the continued tanning of the case following parturition. The egg case per se, attained average CFs of about 1,500 and 850 for Pb and Hg, respectively. Both Pb and Hg showed declining concentration gradients from the exterior to the interior membranes of the wall of the egg case; CFs for Pb declined from 3,500 to 2,000 and for Hg from 5,000 to 500. Comparison of concentrations in separate membranes also demonstrated significant (P < or = 0.01) depurations of Hg from the external and internal membranes during the loss experiments. The presence of radiotracers of Pb and Hg in the internal components of the egg at the end of uptake phase, and prior to the opening of the apertures, confirmed the permeability of the egg case wall to them, consistent with their observed gradients in it. The average CFs for all embryos at the end of the uptake experiment were 34 and 44 for Pb and Hg, respectively, but were significantly (P < 0.001) enhanced for Hg by a factor of 6 in the older eggs. The accumulatory and kinetic characteristics of the egg-case may operate to optimize the exposure of embryos to Pb and Hg following episodic contaminant events in coastal habitats.
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Affiliation(s)
- R A Jeffree
- Radioecology Laboratory, IAEA Marine Environment Laboratories, 4 Quai Antoine 1er, Monaco, MC, 98000, Monaco.
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