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Bradford MA, Mallory ML, O'Driscoll NJ. Ecology and environmental characteristics influence methylmercury bioaccumulation in coastal invertebrates. CHEMOSPHERE 2024; 346:140502. [PMID: 37866498 DOI: 10.1016/j.chemosphere.2023.140502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 10/14/2023] [Accepted: 10/19/2023] [Indexed: 10/24/2023]
Abstract
Quantifying mercury (Hg) concentrations in invertebrates is fundamental to determining risk for bioaccumulation in higher trophic level organisms in coastal food webs. Bioaccumulation is influenced by local mercury concentrations, site geochemistry, individual feeding ecologies, and trophic position. We sampled seven species of invertebrates from five coastal sites in the Minas Basin, Bay of Fundy, and determined body concentrations of methylmercury (MeHg), total mercury (THg), and stable isotopes of nitrogen (δ15N) and carbon (δ13C). To evaluate the effects of environmental chemistry on Hg production and bioaccumulation, bulk sediments from all sites were analysed for THg, %Loss on ignition (LOI) (carbon), and sulfur isotopes (δ34S), and concentrations of MeHg, Total Organic Carbon (TOC), sulfate, and sulfide were measured in porewaters. The mean concentration of MeHg in tissues for all invertebrates sampled was 10.03 ± 7.04 ng g-1). MeHg in porewater (mean = 0.22-1.59 ng L-1) was the strongest predictor of invertebrate MeHg, but sediment δ34S (-0.80-14.1‰) was also a relatively strong predictor. δ34S in tissues (measured in three species; Corophium volutator, Ilyanassa obsoleta, and Littorina littorea) were positively related to MeHg in invertebrates (r = 0.55, 0.22, and 0.71 respectively), and when used in combination with δ15N and δ13C values improved predictions of Hg concentrations in biota. Hg concentrations in the amphipod Corophium volutator (mean MeHg = 10.60 ± 1.90 ng g-1) were particularly well predicted using porewater and sediment chemistry, highlighting this species as a useful bioindicator of Hg contamination in sediments of the Bay of Fundy.
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Affiliation(s)
- Molly A Bradford
- Earth and Environmental Science Department, Acadia University, Wolfville, Nova Scotia, Canada.
| | - Mark L Mallory
- Biology Department, Acadia University, Wolfville, Nova Scotia, Canada
| | - Nelson J O'Driscoll
- Earth and Environmental Science Department, Acadia University, Wolfville, Nova Scotia, Canada
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2
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Pettamanna A, Raghav D, Nair RH. Hepatic Toxicity in Etroplus suratensis (Bloch 1790): An Economically Important Edible Fish in Vembanad Fresh Water Lake, Kerala, India. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2020; 105:565-571. [PMID: 32918564 DOI: 10.1007/s00128-020-02987-7] [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: 04/28/2020] [Accepted: 09/03/2020] [Indexed: 06/11/2023]
Abstract
Fish consumption from contaminated water-bodies is a serious health issue. This study conducted to reveal the presence of heavy metals and bisphenols in Vembanad lake, an exploiting tourist spot in Kerala, receiving untreated agricultural, domestic, municipal, and industrial effluents. We evaluated aquatic contaminant impact on hepatic stress markers in Etroplus suratensis from fragile Vembanad lake. The significant difference in water physiochemical parameters, the concentration of heavy metals, and bisphenols (BPA and BPS) were studied. Hepatic tissue of E. suratensis inhabited in lake featured with high iron (11.29 ± 0.39 ppm) and BPA (0.02412 ± 0.0031 µg/mL) content along with an increased hepatic stress marker and distorted hepatic structure. The study highlights the presence of high iron and BPA in edible fish. The study recommends monitoring of physiochemical characters of freshwater lakes is essential for better survival of freshwater flora and fauna.
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Affiliation(s)
- Arathi Pettamanna
- Physiology Research Laboratory, School of Biosciences, Mahatma Gandhi University, Kottayam, Kerala, 686560, India
| | - Divya Raghav
- Physiology Research Laboratory, School of Biosciences, Mahatma Gandhi University, Kottayam, Kerala, 686560, India
| | - Raveendran Harikumaran Nair
- Physiology Research Laboratory, School of Biosciences, Mahatma Gandhi University, Kottayam, Kerala, 686560, India.
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3
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Evidence of Mercury Methylation and Demethylation by the Estuarine Microbial Communities Obtained in Stable Hg Isotope Studies. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15102141. [PMID: 30274240 PMCID: PMC6210349 DOI: 10.3390/ijerph15102141] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/25/2018] [Accepted: 09/25/2018] [Indexed: 11/17/2022]
Abstract
Microbial activity is a critical factor controlling methylmercury formation in aquatic environments. Microbial communities were isolated from sediments of two highly mercury-polluted areas of the Tagus Estuary (Barreiro and Cala do Norte) and differentiated according to their dependence on oxygen into three groups: aerobic, anaerobic, and sulphate-reducing microbial communities. Their potential to methylate mercury and demethylate methylmercury was evaluated through incubation with isotope-enriched Hg species (199HgCl and CH3201HgCl). The results showed that the isolated microbial communities are actively involved in methylation and demethylation processes. The production of CH3199Hg was positively correlated with sulphate-reducing microbial communities, methylating up to 0.07% of the added 199Hg within 48 h of incubation. A high rate of CH3201Hg degradation was observed and >20% of CH3201Hg was transformed. Mercury removal of inorganic forms was also observed. The results prove the simultaneous occurrence of microbial methylation and demethylation processes and indicate that microorganisms are mainly responsible for methylmercury formation and accumulation in the polluted Tagus Estuary.
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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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5
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Cesário R, Mota AM, Caetano M, Nogueira M, Canário J. Mercury and methylmercury transport and fate in the water column of Tagus estuary (Portugal). MARINE POLLUTION BULLETIN 2018; 127:235-250. [PMID: 29475660 DOI: 10.1016/j.marpolbul.2017.11.066] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 10/25/2017] [Accepted: 11/30/2017] [Indexed: 06/08/2023]
Abstract
Six campaigns were performed in North Channel (CNOR), Barcas Channel (BC) and lower zones (EZ) of Tagus estuary to better understand methylmercury (MMHg) and mercury (Hg) transport and fate. Highest concentrations of particulate and dissolved MMHg were observed in CNOR in bottom waters and in the warmest months. The MMHg distribution coefficients between particulate and dissolved fractions were mainly influenced by particulate matter and dissolved organic carbon. The values were slightly higher in summer than in winter and in CNOR. Overall, results established that the tidal effect is a main driver on the transport and fate of Hg and MMHg from CNOR to outer areas, evidenced by the exportation of the Hg species from CNOR to the upstream station in high tide and to the downstream one in low tide. Therefore, CNOR may be considered a source of Hg and MMHg to the outer estuary.
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Affiliation(s)
- Rute Cesário
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, Lisboa, Portugal; IPMA-Instituto Português do Mar e Atmosfera, Rua Alfredo Magalhães Ramalho, 6, 1495-006 Lisboa, Portugal
| | - Ana Maria Mota
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, Lisboa, Portugal
| | - Miguel Caetano
- IPMA-Instituto Português do Mar e Atmosfera, Rua Alfredo Magalhães Ramalho, 6, 1495-006 Lisboa, Portugal
| | - Marta Nogueira
- IPMA-Instituto Português do Mar e Atmosfera, Rua Alfredo Magalhães Ramalho, 6, 1495-006 Lisboa, Portugal
| | - João Canário
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, Lisboa, Portugal.
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Rodrigues R, Lourenço J, Pereira P, Carvalho S, Mendo S. Effects of metal contamination on the gene expression profile of two benthic species: Cerastoderma edule and Ruditapes philippinarum. MARINE POLLUTION BULLETIN 2017; 125:157-165. [PMID: 28811037 DOI: 10.1016/j.marpolbul.2017.08.014] [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: 02/21/2017] [Revised: 08/03/2017] [Accepted: 08/05/2017] [Indexed: 06/07/2023]
Abstract
This study aimed to identify new biomarkers for metal exposure in two bivalve species. Suppressive Subtractive Hybridization (SSH) was employed to evaluate the transcriptomic response of Cerastoderma edule and Ruditapes philippinarum to metal pollution. Protein synthesis and catalytic activity were the most affected metabolic processes in C. edule and R. philippinarum, respectively. Also, different genes responded to the effect of contamination in each species. The different response observed in both species reinforces the importance of including more than one bioindicator species in risk assessment studies. These results provide the basis for new studies, which are necessary for further validation of the use of the identified genes as molecular biomarkers for metal exposure.
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Affiliation(s)
- Raquel Rodrigues
- Centre for Environmental and Marine Studies and Department of Biology (CESAM), University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
| | - Joana Lourenço
- Centre for Environmental and Marine Studies and Department of Biology (CESAM), University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal
| | - Patrícia Pereira
- Centre for Environmental and Marine Studies and Department of Biology (CESAM), University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal; IPMA - Portuguese Institute for the Sea and Atmosphere, Avenida Brasília, 1449-006 Lisbon, Portugal
| | - Susana Carvalho
- King Abdullah University of Science and Technology (KAUST), Red Sea Research Center (RSRC), Biological and Environmental Sciences and Engineering (BESE), Thuwal 23955-6900, Saudi Arabia
| | - Sonia Mendo
- Centre for Environmental and Marine Studies and Department of Biology (CESAM), University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal
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Machado A, Fernandes AP, Paixão E, Caeiro S, Matias-Dias C. An epidemiological approach to characterise the human exposure pathways in a contaminated estuarine environment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 601-602:1753-1761. [PMID: 28618664 DOI: 10.1016/j.scitotenv.2017.05.108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 05/11/2017] [Accepted: 05/12/2017] [Indexed: 06/07/2023]
Abstract
This study's aim was to develop and implement an integrative epidemiologic cross-sectional study that allows identifying and characterising exposure pathways of populations living and working on the shores of a contaminated estuarine environment. Population residing in Carrasqueira, located on the Sado estuary with known contaminated areas was compared to another population on a noncontaminated estuary (Vila Nova de Mil Fontes - VNMF), considered a nonexposed population. Simple random samples of individuals were selected in each study population from the National Health Service Lists: 140 individuals were selected in Carrasqueira and 219 in VNMF. Participation rates were higher in the exposed group (62.5%, n=102 in Carrasqueira and 48.3%, n=100 individuals in VNMF). The same structured questionnaire was used in both populations, including questions on occupational activities, leisure activities, consumption of food (including fish and mollusks from the estuary) and use of water for human intake and agriculture. Results showed that a significantly higher proportion of Carrasqueira participants reported doing tasks in their job that promote direct (48.8% vs 1.2% in VNMF, p-value<0.001) or indirect (30% vs 11.9% in VNMF, p-value=0.004) contact with water from the estuary. Regarding seafood consumption, the exposed population of Carrasqueira had a higher frequency of consumption of cuttlefish (23.5% vs 9% in VNMF, p-value=0.007), sole (22.5% vs 4% in VNMF, p-value<0.001) and clams (18.6% vs 5.0 in VNMF, p-value=0.004). The comparative study design, with exposed and nonexposed populations living on the shores of two different estuaries allowed us to confirm the hypothesis of a higher risk of contamination from the contaminated estuarine environment. The study design and the selection of both populations were adequate for this type of epidemiologic study of potential routes of human contamination in a mixture of contaminated estuarine environment and can be used in other estuarine areas with similar environmental risk.
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Affiliation(s)
- Ausenda Machado
- Epidemiology Department, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal.
| | - Ana Paula Fernandes
- Departament of Sciences and Technology, Universidade Aberta, Rua da Escola Politécnica, 141, 1269-001 Lisboa, Portugal; CAPP, Centre for Public Administration & Public Policies, Institute of Social Sciences and Politics, Lisbon University, Rua Almerindo Lessa, 1300-663 Lisboa, Portugal
| | - Eleonora Paixão
- Technical Support Center in Areas of Investment, Planning and Statistics, Alentejo Regional Administration of Health, Largo do Jardim do Paraíso, n° 1, 7000-864 Évora, Portugal
| | - Sandra Caeiro
- Departament of Sciences and Technology, Universidade Aberta, Rua da Escola Politécnica, 141, 1269-001 Lisboa, Portugal; CAPP, Centre for Public Administration & Public Policies, Institute of Social Sciences and Politics, Lisbon University, Rua Almerindo Lessa, 1300-663 Lisboa, Portugal
| | - Carlos Matias-Dias
- Epidemiology Department, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal; Centro de investigação em Saúde Pública, Escola Nacional de Saúde Pública, Universidade Nova de Lisboa, Portugal
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Figueiredo NL, Canário J, Serralheiro ML, Carvalho C. Optimization of microbial detoxification for an aquatic mercury-contaminated environment. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2017; 80:788-796. [PMID: 28850004 DOI: 10.1080/15287394.2017.1357311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Mercury (Hg) reduction performed by microorganisms is well recognized as a biological means for remediation of contaminated environment. Recently, studies demonstrated that Hg-resistant microorganisms of Tagus Estuary are involved in metal reduction processes. In the present study, aerobic microbial community isolated from a highly Hg-contaminated area of Tagus Estuary was used to determine the optimization of the reduction process in conditions such as the contaminated ecosystem. Factorial design methodology was employed to examine the influence of glucose, sulfate, iron, and chloride on Hg reduction. In the presence of several concentrations of these elements, microbial community reduced Hg in a range of 37-61% of the initial 0.1 mg/ml Hg2+ levels. The response prediction through central composite design showed that the increase of sulfate concentration led to an optimal response in Hg reduction by microbial community, while the rise in chloride levels markedly decreased metal reduction. Iron may exert antagonistic effects depending upon the media composition. These results are useful in understanding the persistence of Hg contamination in Tagus Estuary after inactivation of critical industrial units, as well as data might also be beneficial for development of new bioremediation strategies either in Tagus Estuary and/or in other Hg-contaminated aquatic environments.
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Affiliation(s)
- Neusa L Figueiredo
- a Department of Toxicological and Food Sciences, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy , Universidade de Lisboa , Lisbon , Portugal
| | - João Canário
- b Department of Chemical Engineering, Centro de Química Estrutural , Instituto Superior Técnico, Universidade de Lisboa , Lisboa , Portugal
| | - Maria Luísa Serralheiro
- c Department of Chemistry and Biochemistry Centro de Química e Bioquímica , Faculdade de Ciências da Universidade de Lisboa , Campo Grande , Lisboa , Portugal
| | - Cristina Carvalho
- a Department of Toxicological and Food Sciences, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy , Universidade de Lisboa , Lisbon , Portugal
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Monteiro CE, Cesário R, O'Driscoll NJ, Nogueira M, Válega M, Caetano M, Canário J. Seasonal variation of methylmercury in sediment cores from the Tagus Estuary (Portugal). MARINE POLLUTION BULLETIN 2016; 104:162-170. [PMID: 26851871 DOI: 10.1016/j.marpolbul.2016.01.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 01/22/2016] [Accepted: 01/25/2016] [Indexed: 06/05/2023]
Abstract
Seasonal and spatial variations of dissolved and particulate methylmercury were evaluated for the first time in sediment cores from the Tagus Estuary. Results showed the highest MeHg concentrations in summer months indicating that the "seasonally" methylation process occurs not only at the topmost layers of the sediments but also in the deeper layers of the sediment column. The proportion of MeHg (up to 92%) in some of our pore water samples was higher than values reported in the literature for other estuaries suggesting that the sedimentary environment in the Tagus tends to favour Hg methylation. This work points to the importance of seasonal variation of the MeHg production in sediment cores. In physically dominated estuaries this enhances seasonal MeHg production in deeper sediments that can have serious ecological impacts due to resuspension or advection processes under extreme events by the increase of MeHg transported to the water column.
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Affiliation(s)
- Carlos Eduardo Monteiro
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001, Lisboa, Portugal; Instituto Português do Mar e da Atmosfera, Rua Alfredo Magalhães Ramalho 6, 1495-006, Lisboa, Portugal
| | - Rute Cesário
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001, Lisboa, Portugal; Instituto Português do Mar e da Atmosfera, Rua Alfredo Magalhães Ramalho 6, 1495-006, Lisboa, Portugal
| | - Nelson J O'Driscoll
- Department of Earth and Environmental Science, Acadia University, Wolfville, Nova Scotia, Canada
| | - Marta Nogueira
- Instituto Português do Mar e da Atmosfera, Rua Alfredo Magalhães Ramalho 6, 1495-006, Lisboa, Portugal
| | - Mónica Válega
- Departamento de Química, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Miguel Caetano
- Instituto Português do Mar e da Atmosfera, Rua Alfredo Magalhães Ramalho 6, 1495-006, Lisboa, Portugal
| | - João Canário
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001, Lisboa, Portugal.
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10
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Noh S, Hong YS, Han S. Application of diffusive gradients in thin films and core centrifugation methods to determine inorganic mercury and monomethylmercury profiles in sediment porewater. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2016; 35:348-356. [PMID: 26250361 DOI: 10.1002/etc.3193] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 04/29/2015] [Accepted: 08/03/2015] [Indexed: 06/04/2023]
Abstract
A diffusive gradient in thin films (DGT) is an in situ sampling technique for the quantitative analysis of contaminant concentrations that is based on the diffusion and adsorption of contaminants on to resin gels. In the present study, a DGT technique was applied to measure total mercury (Hg) and monomethylmercury (MMHg) concentrations in lake and coastal sediment porewaters and compare them with those from ex situ sediment centrifugation. To calculate the total Hg and MMHg concentrations in porewater using the DGT method, the diffusion coefficients of Hg species in a diffusive gel medium was first determined, and then total Hg and MMHg depth profiles were measured using the experimentally determined diffusion coefficients. Using the diffusion coefficients for artificial lake and estuarine waters containing inorganic salts, rather than those for lake and estuarine waters containing Suwannee River humic acid (∼5 mg C L(-1) ), the DGT method demonstrated similar Hg and MMHg profiles to those using the centrifugation method. Based on the need for fine vertical resolution and high metal concentrations to be collected, DGT is suggested to be a reliable method for determining Hg(II) and MMHg depth profiles in sediment porewater.
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Affiliation(s)
- Seam Noh
- School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Yong Seok Hong
- Department of Environmental Engineering, Daegu University, Daegu, Republic of Korea
| | - Seunghee Han
- Department of Environmental Engineering, Daegu University, Daegu, Republic of Korea
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11
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Figueiredo NLL, Canário J, Duarte A, Serralheiro ML, Carvalho C. Isolation and characterization of mercury-resistant bacteria from sediments of Tagus Estuary (Portugal): implications for environmental and human health risk assessment. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2014; 77:155-168. [PMID: 24555656 DOI: 10.1080/15287394.2014.867204] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Mercury (Hg) contamination of aquatic systems has been recognized as a global and serious problem affecting both human and environmental health. In the aquatic ecosystems, mercurial compounds are microbiologically transformed with methylation responsible for generation of methylmercury (MeHg) and subsequent biomagnification in food chain, consequently increasing the risk of poisoning for humans and wildlife. High levels of Hg, especially MeHg, are known to exist in Tagus Estuary as a result of past industrial activities. The aim of this study was to isolate and characterize Hg-resistant bacteria from Tagus Estuary. Mercury-resistant (Hg-R) bacteria were isolated from sediments of two hotspots (Barreiro and North Channel) and one reserve area (Alcochete). Mercury contamination in these areas was examined and bacterial susceptibility to Hg compounds evaluated by determination of minimal inhibitory concentrations (MIC). The isolates characterization was based on morphological observation and biochemical testing. Bacteria characteristics, distribution, and Hg resistance levels were compared with metal levels. Barreiro and North Channel were highly contaminated with Hg, containing 126 and 18 μg/g total Hg, respectively, and in Alcochete, contamination was lower at 0.87 μg/g total Hg. Among the isolates there were aerobic and anaerobic bacteria, namely, sulfate-reducing bacteria, and Hg resistance levels ranged from 0.16 to 140 μg/ml for Hg(2+) and from 0.02 to 50.1 μg/ml for MeHg. The distribution of these bacteria and the resistance levels were consistent with Hg contamination along the depth of the sediments. Overall, results show the importance of the characterization of Tagus Estuary bacteria for ecological and human health risk assessment.
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MESH Headings
- Bacteria, Aerobic/drug effects
- Bacteria, Aerobic/isolation & purification
- Bacteria, Anaerobic/drug effects
- Bacteria, Anaerobic/isolation & purification
- Chromatography, Gas
- Environmental Health
- Environmental Monitoring
- Estuaries
- Geologic Sediments/chemistry
- Geologic Sediments/microbiology
- Humans
- Mercury/analysis
- Mercury/pharmacology
- Methylmercury Compounds/analysis
- Methylmercury Compounds/pharmacology
- Microbial Sensitivity Tests
- Portugal
- Risk Assessment
- Spectrophotometry, Atomic
- Water Pollutants, Chemical/analysis
- Water Pollutants, Chemical/pharmacology
- Water Pollution, Chemical/adverse effects
- Water Pollution, Chemical/analysis
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Affiliation(s)
- Neusa L L Figueiredo
- a Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia , Universidade de Lisboa Av. Prof. Gama Pinto , Lisboa , 1649-003 , Portugal
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12
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Edmonds ST, O'Driscoll NJ, Hillier NK, Atwood JL, Evers DC. Factors regulating the bioavailability of methylmercury to breeding rusty blackbirds in northeastern wetlands. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2012; 171:148-154. [PMID: 22922392 DOI: 10.1016/j.envpol.2012.07.044] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 07/25/2012] [Accepted: 07/29/2012] [Indexed: 06/01/2023]
Abstract
Rusty blackbirds are undergoing rapid population decline and have elevated Hg concentrations while breeding in the Acadian ecoregion of North America. Factors regulating the bioavailability of methyl-Hg (MeHg) within this population's habitat were determined using water, invertebrates, and blood from adult rusty blackbirds collected for Hg-speciation, along with additional water column parameters: MeHg and THg, dissolved organic carbon, pH, dissolved oxygen, conductivity, redox potential, and temperature. Both DO(2) and pH were negatively related to biota MeHg, while water MeHg concentrations were positively related. Both invertebrate MeHg concentration and %MeHg increased with trophic level. Invertebrate MeHg concentrations were among the greatest reported when compared with those reported elsewhere for wetlands and waterbodies-often several times greater for similar taxa-while percent MeHg of THg were similar. An environment with high bioavailability of MeHg in combination with a high trophic position best explains elevated Hg concentrations for this species regional population.
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Affiliation(s)
- Samuel Trower Edmonds
- K.C. Irving Environmental Science Centre, Department of Earth and Environmental Sciences, Acadia University, Wolfville, NS B4P 2R6, Canada.
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Chatterjee M, Canário J, Sarkar SK, Branco V, Godhantaraman N, Bhattacharya BD, Bhattacharya A. Biogeochemistry of mercury and methylmercury in sediment cores from Sundarban mangrove wetland, India--a UNESCO World Heritage Site. ENVIRONMENTAL MONITORING AND ASSESSMENT 2012; 184:5239-5254. [PMID: 21968876 DOI: 10.1007/s10661-011-2336-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Accepted: 08/29/2011] [Indexed: 05/31/2023]
Abstract
This study was performed to elucidate the distribution, concentration trend and possible sources of total mercury (Hg(T)) and methylmercury (MeHg) in sediment cores (<63 μm particle size; n = 75) of Sundarban mangrove wetland, northeastern part of the Bay of Bengal, India. Total mercury was determined by atomic absorption spectrometry (AAS) in a Leco AMA 254 instrument and MeHg by gas chromatography-atomic fluorescence spectrometry (GC-AFS). A wide range of variation in Hg(T) (0.032-0.196 μg g(-1) dry wt.) as well as MeHg (0.04-0.13 ng g(-1) dry wt.) concentrations revealed a slight local contamination. The prevalent low Hg(T) levels in sediments could be explained by sediment transport by the tidal Hugli (Ganges) River that would dilute the Hg(T) values via sediment mixing processes. A broader variation of MeHg proportions (%) were also observed in samples suggesting that other environmental variables such as organic carbon and microbial activity may play a major role in the methylation process. An overall elevated concentration of Hg(T) in surface layers (0-4 cm) of the core is due to remobilization of mercury from deeper sediments. Based on the index of geoaccumulation (I (geo)) and low effects-range (ER-L) values, it is considered that the sediment is less polluted by Hg(T) and there is less ecotoxicological risk. The paper provides the first information of MeHg in sediments from this wetland environment and the authors strongly recommend further examination of Hg(T) fluxes for the development of a detailed coastal MeHg model. This could provide more refine estimates of a total flux into the water column.
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Affiliation(s)
- Mousumi Chatterjee
- Department of Marine Science, University of Calcutta, 35, B.C. Road, Calcutta, India
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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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15
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Fonseca VF, França S, Serafim A, Company R, Lopes B, Bebianno MJ, Cabral HN. Multi-biomarker responses to estuarine habitat contamination in three fish species: Dicentrarchus labrax, Solea senegalensis and Pomatoschistus microps. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2011; 102:216-27. [PMID: 21356184 DOI: 10.1016/j.aquatox.2011.01.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 01/04/2011] [Accepted: 01/28/2011] [Indexed: 05/11/2023]
Abstract
Several biomarker responses were determined in three fish species, Dicentrarchus labrax, Solea senegalensis and Pomatoschistus microps, from two estuaries of the Portuguese coast, Ria de Aveiro and Tejo. Both estuaries have significant anthropogenic influences from multiple sources (industrial, agricultural and shipping activities), which was evident from sediment chemical characterization concerning metal (copper, zinc, nickel, lead and chromium) and polycyclic aromatic hydrocarbon (PAH) concentrations. Spatial variability in fish responses was observed across species for most biomarkers of exposure [the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), ethoxyresorufin O-deethylase (EROD) and glutathione S-transferase (GST), and metallothionein concentrations (MT)] and effect biomarkers [lipid peroxidation (LPO), RNA to DNA ratio (R:D), protein and lipid content]. In general, the interspecific differences in biomarker responses were greater than the spatial differences, due to differences in the behavior and habitat use of the species. Nevertheless, similarities were also observed considering both chemical load and biomarker responses. In highly polluted sites fish showed in general a significant antioxidant enzyme induction, associated with decreased R:D values, while fish from the least impacted site had little enzyme induction and better condition indices (high R:D and low LPO values). EROD activity was also higher for all species in the Tejo than Ria de Aveiro estuary, despite the generally higher total PAH measured in Ria de Aveiro, most likely due to a higher proportion of 4 and 6-ring PAHs, considered more toxic than low molecular weight PAHs, in the Tejo. In conclusion, this multi-biomarker approach considering multiple species provided improved understanding of the diverse responses and effects of exposure to contaminants and the effective risk it poses for different fish species.
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Affiliation(s)
- V F Fonseca
- Centro de Oceanografia, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Portugal.
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16
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Gnandi K, Han S, Rezaie-Boroon MH, Porrachia M, Deheyn DD. Increased bioavailability of mercury in the lagoons of Lomb, Togo: the possible role of dredging. AMBIO 2011; 40:26-42. [PMID: 21404821 PMCID: PMC3357720 DOI: 10.1007/s13280-010-0094-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Surface sediments of the lagoons of Lomé, Togo, were analyzed for mercury, methylmercury, and trace elements. Concentrations were greater than typical for natural lagoon sediments, and with greater variability within the Eastern lagoon compared to the Western one. The Eastern lagoon is larger and has been dredged in the past, while the Western lagoon, which also receives major waste inputs, has not been dredged and shows less tidal flushing. Accordingly, one naturally believes that the Eastern lagoon is cleaner and probably safe to use due to its natural resources, including fishes to eat. Unexpectedly, we describe here that mercury methylation was greater in the Eastern lagoon, indicating increased bioavailability of mercury, as probably facilitated by past dredging that decreased solid-phase retention of inorganic mercury. Urbanization has historically been more developed in the southern part of the lagoons, which is still reflected in contamination levels of sediment despite dredging, probably because sources of contamination are still more important there today. Such urban contamination emphasizes the need to regulate waste discharges and possible airborne contamination in growing cities of developing countries, and implements environmental and public health monitoring, especially in relation to misbelieves systematically associated with the cleansing effect of dredging activity.
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Affiliation(s)
- Kissao Gnandi
- Geology Department, University of Lomé, Lomé, Togo
- Environmental Geochemistry and Hydrogeology Department, Faculty of Sciences, University of Lomé, BP 1515 Lomé, Togo
| | - Seunghee Han
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0202 USA
- Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology, 261 Cheomdan-gwagiro, Buk-gu, Gwangju, 500-712 Republic of Korea
| | - M. Hassan Rezaie-Boroon
- Geological Sciences Department, California State University Los Angeles, 5151 State University Drive, Los Angeles, CA 90032 USA
| | - Magali Porrachia
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0202 USA
| | - Dimitri D. Deheyn
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0202 USA
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17
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Cardoso PG, Lillebø AI, Pereira E, Duarte AC, Pardal MA. Different mercury bioaccumulation kinetics by two macrobenthic species: the bivalve Scrobicularia plana and the polychaete Hediste diversicolor. MARINE ENVIRONMENTAL RESEARCH 2009; 68:12-8. [PMID: 19395081 DOI: 10.1016/j.marenvres.2009.03.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Revised: 03/17/2009] [Accepted: 03/25/2009] [Indexed: 05/21/2023]
Abstract
Mercury is a global priority pollutant and given its huge relevance in terms of environmental damage and a threat to human health, it is important to study the bioaccumulation processes at the level of macrobenthic organisms and evaluate possible consequences for the trophic chain. In this work we evaluate the mercury accumulation rates of two distinct and economically important macrobenthic species, the polychaete Hediste diversicolor and the bivalve Scrobicularia plana, through a mesocosms laboratory experiment. The present experiment demonstrated different bioaccumulation kinetics for each species: while S. plana has a rapid accumulation after 48 h of exposure to contaminated sediments and then reaches a steady state, H. diversicolor has a linear mercury accumulation throughout the experiment time (31 days). The different patterns observed can be related to different feeding strategies and assimilation efficiencies. In addition, we can conclude that independently of the mercury concentration in the sediments, the two studied species in both contaminated sediments reached the same percentage (25%) of mercury accumulated at the end of the experiment when compared to the maximum concentrations recorded in the field. This experiment highlights that the mercury bioaccumulation rate by these two economically and ecologically important macrobenthic species is a reasonably rapid process which can promote serious consequences for the higher trophic levels, constituting a severe risk to the natural environment and ultimately to human health.
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Affiliation(s)
- P G Cardoso
- IMAR-Institute of Marine Research, Department of Zoology, University of Coimbra, 3004-517 Coimbra, Portugal.
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18
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Kwokal Z, Sarkar SK, Chatterjee M, Franciskovis-Bilinski S, Bilinski H, Bhattacharya A, Bhattacharya BD, Alam MA. An assessment of mercury loading in core sediments of Sunderban mangrove wetland, India (a preliminary report). BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2008; 81:105-112. [PMID: 18506380 DOI: 10.1007/s00128-008-9443-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2007] [Accepted: 04/15/2008] [Indexed: 05/26/2023]
Abstract
This is a preliminary report on total mercury (T(Hg)) in core sediments (<63 microm particle size) of Sunderban mangrove wetland, northeastern part of the Bay of Bengal, India. Cold vapor atomic absorption spectrometry (CVAAS) was used for T(Hg) determination. The concentration varies from 9.8 to 535.1 ppb (ngg(-1)). Results revealed variations over premonsoon and postmonsoon month at different core depth, as well as in studied three sampling stations, located at the site of three rivers: Hugli River (S(1)), Matla River (S(2)) and Bidyadhari River (S(3)). Elevated concentration of T(Hg) in subsurface layer (4-8 cm) of the core at S(2) is attributed to remobilization of mercury from deeper sediment (32-36 cm). Positive correlation is present between total Hg and clay content. Based on index of geoaccumulation (I(geo)) and Effects-Range Low (ER-L) value (150 ppb) it is considered that the sediments are till now unpolluted. As a consequence, there is less chance of ecotoxicological risk to organisms living in studied sediments. Two statistical methods were applied to determine T(Hg) anomalies. Box plot method showed one extreme and three outliers in S(1) at postmonsoon season. Two extremes were found at S(2) at 4-8 and at 32-36 cm in premonsoon period. In S(3) there was no anomaly by box plot method. MAD method was more sensitive than box plot method and T(Hg) anomaly was detected at 12-16 cm in S(3) during postmonsoon season. The data reported are useful baselines for T(Hg) in Sunderban mangrove wetland, India and would be of help in future sediment quality studies.
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Affiliation(s)
- Z Kwokal
- Centre for Marine and Environmental Research, Rudjer Boskovic Institute, P.O. Box 180, 10001 Zagreb, Croatia
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19
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Mercury enrichments in core sediments in Hugli–Matla–Bidyadhari estuarine complex, north-eastern part of the Bay of Bengal and their ecotoxicological significance. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/s00254-008-1404-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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20
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Cardoso PG, Lillebø AI, Lopes CB, Pereira E, Duarte AC, Pardal MA. Influence of bioturbation by Hediste diversicolor on mercury fluxes from estuarine sediments: a mesocosms laboratory experiment. MARINE POLLUTION BULLETIN 2008; 56:325-334. [PMID: 18054965 DOI: 10.1016/j.marpolbul.2007.10.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 10/15/2007] [Accepted: 10/23/2007] [Indexed: 05/25/2023]
Abstract
Mercury, with its reactive forms being the most deleterious for the trophic chains, has been identified as a major pollutant in a few confined bodies of the coastal zone. Due to feeding, burrowing, and bioirrigation activities, infauna are known to play a crucial role in the biogeochemical processes of contaminants. The main goal of the present study is to evaluate the effects of Hediste diversicolor bioturbation on mercury fluxes from estuarine sediments in a mesocosms laboratory experiment. Additionally, an attempt was made to establish a relationship between the amount of remobilised mercury to the water column and the degree of contamination of the sediments using a mercury contamination gradient. The present experiment demonstrated that the bioturbation activity caused by the gallery-diffuser H. diversicolor did not influence the remobilisation of mercury (in dissolved reactive forms) from the sediment to the water column. The concentration of dissolved reactive mercury in the water column also did not reflect the degree of contamination in the sediments. The results obtained were in accordance with the sediment characteristics of the Mondego Estuary and Ria de Aveiro (Portugal), since they are very rich in organic matter content, iron/manganese total and hydrous oxides. These physicochemical characteristics of the sediments may partially justify the retention of mercury by these systems, even when they are subjected to bioturbation. In conclusion, sediments with high organic matter content and a high concentration of iron/manganese hydrous oxides allowed for efficient retention of mercury, and the bioturbation process did not seem to affect the system. Another conclusion from this study is that the remobilisation of mercury by bioturbation to the water column is not a fast process, requiring more than 24h. This study constitutes an important work in the area of the effects of bioturbation on mercury remobilisation. Considering the toxicity of mercury for the biota, it is essential to evaluate the real magnitude of mercury processes occurring in estuarine systems in order to obtain essential information on metal behaviour.
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Affiliation(s)
- P G Cardoso
- IMAR, Institute of Marine Research, Department of Zoology, University of Coimbra, Coimbra, Portugal.
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21
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Poissant L, Constant P, Pilote M, Canário J, O'Driscoll N, Ridal J, Lean D. The ebullition of hydrogen, carbon monoxide, methane, carbon dioxide and total gaseous mercury from the Cornwall Area of Concern. THE SCIENCE OF THE TOTAL ENVIRONMENT 2007; 381:256-62. [PMID: 17499842 DOI: 10.1016/j.scitotenv.2007.03.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 03/06/2007] [Accepted: 03/15/2007] [Indexed: 05/15/2023]
Abstract
This paper reports the first ebullitive fluxes of hydrogen (H2), carbon monoxide (CO), methane (CH4), carbon dioxide (CO2) and total gaseous mercury (TGM) from the Cornwall Area of Concern (CAC). Although sediments were contaminated with mercury, bubbling was a negligible source of mercury for the global atmosphere. Indeed, the average emission of TGM through ebullition was 0.04 pg m(-2) h(-1). Measurements of H2, CO, CH4 and CO2 trapped gas concentrations and fluxes were used as indicators of diagenesis processes. The CAC represented a significant regional source of CH4 since the estimated ebullitive fluxes (3.5 mg m(-2) h(-1)) were similar to the CH4 emissions measured above typical flooded freshwater wetlands. As molecular diffusion is known as the main pathway of CO2 transport from water to the atmosphere, CO2 ebullitive fluxes were weak (0.39 mg m(-2) h(-1)). Bubbling of CO (1.6 microg m(-2) h(-1)) was 10 folds less important than CO fluxes measured over flooded freshwater wetlands. Finally, H2 emissions (0.001 microg m(-2) h(-1)) were negligible since the level of this trace gas is tightly regulated by microorganisms in anaerobic environments.
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Affiliation(s)
- Laurier Poissant
- Science and Technology Branch, Environment Canada, 105 McGill street, 7th floor (Youville), Montréal, Québec, Canada H2Y 2E7.
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22
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Canário J, Branco V, Vale C. Seasonal variation of monomethylmercury concentrations in surface sediments of the Tagus Estuary (Portugal). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2007; 148:380-3. [PMID: 17240023 DOI: 10.1016/j.envpol.2006.11.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Revised: 11/18/2006] [Accepted: 11/26/2006] [Indexed: 05/13/2023]
Abstract
Surface sediments (0-2cm) were collected at 40 sites along the Tagus Estuary in July and December 2004. The sediments were analysed for total mercury, monomethylmercury (MMHg) and interpretative parameters (e.g. redox potential, pH, C(org)). No significant differences in total Hg, pH, Al, Fe, Mn and C(org) were found between sediments collected in the two periods, but MMHg concentrations were higher in July. On average sediments were warmer and more reducing in summer. On the basis of these results, an increase of 7kg of MMHg (+37%) in surface sediments of the Tagus Estuary was estimated. Presumably higher temperatures in summer promote the increase of microbial activity and higher methylation rates. The alterations observed in this study point to the potential importance of seasonal changes in MMHg production at surface sediments with eventual changes in the MMHg uptake by benthic invertebrates and other organisms in the food web.
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Affiliation(s)
- João Canário
- IPIMAR, National Institute for Agronomy and Fisheries Research, Av Brasília, Lisbon, Portugal.
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23
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Castro P, Valiela I, Freitas H. The use of sedimentary %C, %N, delta(15)N, and Pb concentrations to assess historical changes in anthropogenic influence on Portuguese estuaries. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2007; 147:706-12. [PMID: 17129649 DOI: 10.1016/j.envpol.2006.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2005] [Revised: 09/06/2006] [Accepted: 09/09/2006] [Indexed: 05/12/2023]
Abstract
Vertical profiles of C, N, delta(15)N and Pb were measured in the Mondego and Mira estuaries as markers that conveyed notions as to the relative influence of anthropogenic influence over the past decades. Recent carbon changes in both estuaries may reflect changes in estuarine productivity, probably as a consequence of sediment reworking and erosion, and also of losses in salt marsh area and dwarf eelgrass beds. delta(15)N values began to diverge considerably before the %C and %N and were higher in Mondego. delta(15)N signatures detected N enrichment at relatively low rates, and indicated that Mondego received more enriched N than Mira. Lead concentrations differed between estuaries, with higher concentrations in Mondego. The secular increase in %N, Pb, and delta(15)N signatures was significantly related to human density in the watersheds of the estuaries and were sensitive indicators of anthropogenic activity.
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Affiliation(s)
- Paula Castro
- IMAR, Institute of Marine Research, Department of Botany, University of Coimbra, Travessa Martim de Freitas, Coimbra, Portugal.
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24
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Coelho JP, Pimenta J, Gomes R, Barroso CM, Pereira ME, Pardal MA, Duarte A. Can Nassarius reticulatus be used as a bioindicator for Hg contamination? Results from a longitudinal study of the Portuguese coastline. MARINE POLLUTION BULLETIN 2006; 52:674-80. [PMID: 16337247 DOI: 10.1016/j.marpolbul.2005.10.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2005] [Revised: 10/20/2005] [Accepted: 10/25/2005] [Indexed: 05/05/2023]
Abstract
The focus of this work is to explore the use of the netted whelk, Nassarius reticulatus (L.), as an indicator of mercury (Hg) contamination, by assessing the concentration of Hg in the sediments and in the whelk along the entire Portuguese coast. Total Hg concentrations ranged from below the detection limit (0.01 ng absolute mercury) up to 0.87 mg kg(-1) dry weight (dwt) in sediments and between 0.06 and 1.02 mg kg(-1) (dwt) for organisms, with no significant differences between males and females. Although organic mercury was not detected in the sediments, it represented, on average, 52% of the total Hg in the whelk tissues, and as high as 88% in some cases, suggesting mercury accumulation from dietary intake. Significant negative correlations were found between the total Hg concentrations in the sediments and the log(10) of Hg concentrations in whelk tissues males (r=-0.64; P<0.01) and females (r=-0.52; P<0.01) indicating that the species is a poor indicator of Hg contamination. Nevertheless, since the highest concentrations of organic mercury in the whelk tissues were found in the least contaminated areas, this species must be highly relevant in the trophic web, namely on the possible biomagnification of mercury. The high dietary mercury accumulation from feeding on carrion and the low bioavailability of mercury to whelks in estuarine sediments may be the basis of the mercury accumulation pattern in N. reticulatus.
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Affiliation(s)
- J P Coelho
- Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
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25
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Green-Ruiz C, Ruelas-Inzunza J, Páez-Osuna F. Mercury in surface sediments and benthic organisms from Guaymas Bay, east coast of the Gulf of California. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2005; 27:321-9. [PMID: 16027967 DOI: 10.1007/s10653-004-5741-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2004] [Accepted: 11/01/2004] [Indexed: 05/03/2023]
Abstract
In order to know the concentration of mercury in surface sediments, macroalgae and clams from Guaymas Bay, Mexico, 20 surface sediment samples and several individuals of Codium amplivesciculatum (3), Enteromorpha clathrata (4), Gracilaria subsecundata (2), Ulva lactuca (2), Chione subrugosa (80) and Crassostrea gigas (40) were collected and their Hg concentration was measured by a cold vapor Hg analyzer, after acid digestion. In addition, granulometric analysis and quantification of total organic carbon, aluminum, iron and manganese contents in sediments were performed. A Pearsons correlation matrix was determined and, the enrichment factor, the geoaccumulation index and the biota-sediment accumulation factor were calculated. Mercury concentrations in sediments ranged from 0.3 to 2.3 microg g(-1), with the central and northern portions showing the highest values. Macroalgae had a content of Hg that oscillated from 0.058 to 0.134 microg g(-1), while the average concentrations of this metal for clams and oysters were 0.063 and 0.230 microg g(-1), respectively. A clear effect of Guaymas City and the anthropogenic activities carried out around the Guaymas Bay has been observed and the enrichment factor and the geochemical index suggest that sediments from this coastal ecosystem are moderately to strongly contaminated with Hg. However, according to the figure of the maximum human consumption of Hg per week recommended by the World Health Organization, people can ingest clams without risk to their health.
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Affiliation(s)
- C Green-Ruiz
- Institute of Marine Sciences and Limnology, Mazatlán Academic Unit, National Autonomous University of Mexico, Av. Joel Montes Camarena s/n, Col. Centro, Mazatlán 82000, Sinaloa, México.
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26
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Canário J, Vale C, Caetano M. Distribution of monomethylmercury and mercury in surface sediments of the Tagus Estuary (Portugal). MARINE POLLUTION BULLETIN 2005; 50:1142-5. [PMID: 16099476 DOI: 10.1016/j.marpolbul.2005.06.052] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 06/17/2005] [Accepted: 06/22/2005] [Indexed: 05/04/2023]
Affiliation(s)
- J Canário
- IPIMAR-National Institute for Agronomy and Fisheries Research, Av. Brasília, 1449-006 Lisbon, Portugal.
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27
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Canário J, Vale C. Rapid release of mercury from intertidal sediments exposed to solar radiation: a field experiment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2004; 38:3901-3907. [PMID: 15298199 DOI: 10.1021/es035429f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
There is increasing evidence of the primary importance of photochemical reactions and transfer of gaseous mercury to the atmosphere. Although mercury in aquatic sediments is efficiently retained, resuspension and bioturbation in intertidal sediments may expose temporarily anoxic sediments to solar radiation. Field experiments were performed to investigate these processes. Anoxic sediments from two areas in the Tagus estuary with different degrees of Hg contamination (experiments I and II) were homogenized and distributed into two sets of 36 uncovered Petri dishes. The samples were placed on the intertidal sediments and exposed to direct solar radiation and kept under dark (control) for 6-8 h. The decrease rates of acid volatile sulfides (abrupt in the first 3 h) and of pyrite (linear) were the same in sediments under solar radiation and dark. The total Hg concentrations were relatively constant in sediments kept in dark, but decreased from 17.6 to 7.65 and 3.45 to 1.35 nmol g(-1) in experiments I and II, respectively. In those exposed to solar radiation during the period of higher UV intensity. Similar evolutions were found in nonreactive Hg in pore waters (3.00-2.59 and 0.725-0.105 nM). On the contrary, reactive Hg was higher in pore waters of the sediments exposed to solar radiation and increased with time, from 424 to 845 pM and 53 to 193 pM. These results indicate that most mercury released in pore waters was photochemically reduced in a short period of time and escaped rapidly to the atmosphere. Episodes of bottom resuspension and bioturbation in the intertidal sediments enhance the transfer of gaseous mercury to the atmosphere.
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Affiliation(s)
- João Canário
- National Institute for Agronomy and Fisheries Research, IPIMAR, Av. Brasília, 1449-006 Lisboa, Portugal.
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