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Gallorini A, Loizeau JL. Lake snow as a mercury methylation micro-environment in the oxic water column of a deep peri-alpine lake. Chemosphere 2022; 299:134306. [PMID: 35337820 DOI: 10.1016/j.chemosphere.2022.134306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/08/2022] [Accepted: 03/11/2022] [Indexed: 06/14/2023]
Abstract
Hg methylation in the oxic water column of marine environments has been linked to the presence of suspended and settling particles known as marine snow, which acts as a micro-niche for MeHg production. While marine snow has been thoroughly studied, its freshwater counterpart, lake snow, received less attention, even though few works have highlighted its ability to be a micro environment for Hg methylation in freshwater systems. Here we present new data of MeHg and THg concentrations in the lake snow of a deep peri-alpine lake (Lake Geneva, Switzerland-France). Particles were sampled from the lake and from its main tributaries using continuous flow filtration and continuous flow centrifugation, respectively. MeHg concentrations ranged from 0.48 ± 0.09 ng/g to 9.61 ± 0.67 ng/g in the lake particles, and from 0.30 ± 0.08 ng/g to 2.41 ± 0.14 ng/g in tributary particles. Our results suggest that lake snow is a likely micro-niche for Hg methylation, like marine snow, and that this methylation takes place inside the particles with a subsequent diffusion to the water column. Moreover, we propose a conceptual model to explain the MeHg behavior related to the lake snow along Lake Geneva water column and a mass balance model to estimate the time required to reach the steady state of MeHg in the water column. Our calculation indicates that the steady-state is reached after 37 days. This result is compatible with particles residence times from the literature on Lake Geneva. These particles forming the lake snow are probably a major entry point into the lake's food chain.
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Affiliation(s)
- Andrea Gallorini
- Department F.-A. Forel for Environmental and Aquatic Sciences, University of Geneva, Boulevard Carl-Vogt 66, 1205, Geneva, Switzerland.
| | - Jean-Luc Loizeau
- Department F.-A. Forel for Environmental and Aquatic Sciences, University of Geneva, Boulevard Carl-Vogt 66, 1205, Geneva, Switzerland
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Zhong J, Wen S, Zhang L, Wang J, Liu C, Yu J, Zhang L, Fan C. Nitrogen budget at sediment-water interface altered by sediment dredging and settling particles: Benefits and drawbacks in managing eutrophication. J Hazard Mater 2021; 406:124691. [PMID: 33296762 DOI: 10.1016/j.jhazmat.2020.124691] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 06/12/2023]
Abstract
Internal nitrogen (N) loading of lakes is commonly controlled by sediment dredging, although its comprehensive effect on internal N loading remains unclear. Herein, we examined the long-term effects of sediment dredging on internal N loading from a new perspective on the N budget at the sediment-water interface (SWI) through a simulation of field dredging performed by incubating intact sediment cores from a shallow eutrophic lake (Lake Taihu). We further evaluated the role of settling particles (SP) in the recovery of N cycle processes after dredging and its potential impact on the N budget. Our results demonstrated that dredging could help reduce organic matter and total N in sediments; improve the redox environment of the SWI; slow down N mineralization, N fixation, denitrification, and anaerobic ammonia oxidation (anammox); and alter the N budget at the SWI and the contribution of various N cycle processes. However, the input of SP enriched in fresh organic matter and N could accelerate the recovery of N cycle processes at the SWI, reducing the variation in the N budget and the contribution of each N cycle process caused by dredging. Dredging significantly reduced the N flux at the SWI, which was evident from the reduction of inorganic N release flux and N removal through denitrification and anammox. Therefore, sediment dredging has its advantages and disadvantages in managing internal N loading in lakes. To maintain a long-term control on the release of internal N through sediment dredging, measures should be taken based on the in-lake and watershed to inhibit the inflow and settlement of particulate matter.
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Affiliation(s)
- Jicheng Zhong
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China.
| | - Shuailong Wen
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Lu Zhang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Jianjun Wang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Cheng Liu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Juhua Yu
- Institute of Soil and Fertilizer, Fujian Academy of Agricultural Sciences, Fuzhou 350013, China
| | - Lei Zhang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Chengxin Fan
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
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Díez EG, Graham ND, Loizeau JL. Total and methyl-mercury seasonal particulate fluxes in the water column of a large lake (Lake Geneva, Switzerland). Environ Sci Pollut Res Int 2018; 25:21086-21096. [PMID: 29770934 DOI: 10.1007/s11356-018-2252-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 05/07/2018] [Indexed: 06/08/2023]
Abstract
Concentrations and fluxes of total and methylmercury were determined in surface sediments and associated with settling particles at two sites in Lake Geneva to evaluate the sources and dynamics of this toxic contaminant. Total mercury concentrations measured in settling particles were different throughout the seasons and were greatly influenced by the Rhone River particulate inputs. Total mercury concentrations closer to shore (NG2) ranged between 0.073 ± 0.001 and 0.27 ± 0.01 μg/g, and between 0.038 ± 0.001 and 0.214 ± 0.008 μg/g at a site deeper in the lake (NG3). Total mercury fluxes ranged between 0.144 ± 0.002 and 3.0 ± 0.1 μg/m2/day at NG2, and between 0.102 ± 0.008 and 1.32 ± 0.08 μg/m2/day at NG3. Combined results of concentrations and fluxes showed that total mercury concentrations in settling particles are related to the season and particle inputs from the Rhone River. Despite an observed decrease in total mercury fluxes from the coastal zone towards the open lake, NG3 (~ 3 km from the shoreline) was still affected by the coastal boundary, as compared to distal sites at the center of the lake. Thus, sediment focusing is not efficient enough to redistribute contaminant inputs originating from the coastal zones, to the lake center. Methylmercury concentrations in settling particles largely exceeded the concentrations found in sediments, and their fluxes did not show significant differences with relation to the distance from shore. The methylmercury found associated with settling particles would be related to the lake's internal production rather than the effect of transport from sediment resuspension.
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Affiliation(s)
- Elena Gascón Díez
- Department F.-A. Forel for Environmental and Aquatic Sciences, and Institute for Environmental Sciences, University of Geneva, Boulevard Carl-Vogt 66, 1211, Geneva 4, Switzerland.
| | - Neil D Graham
- Soil and Water Infrastructure, Biology Centre CAS, Na Sádkách 7, 370 05, České Budějovice, Czech Republic
| | - Jean-Luc Loizeau
- Department F.-A. Forel for Environmental and Aquatic Sciences, and Institute for Environmental Sciences, University of Geneva, Boulevard Carl-Vogt 66, 1211, Geneva 4, Switzerland
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Sanchez-Vidal A, Llorca M, Farré M, Canals M, Barceló D, Puig P, Calafat A. Delivery of unprecedented amounts of perfluoroalkyl substances towards the deep-sea. Sci Total Environ 2015; 526:41-48. [PMID: 25918891 DOI: 10.1016/j.scitotenv.2015.04.080] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 04/20/2015] [Accepted: 04/21/2015] [Indexed: 06/04/2023]
Abstract
The finding of perfluoroalkyl substances (PFASs) in particles sinking to the deep northwestern Mediterranean Sea confirms the role of the latter as ballast for the transfer of pollutants to the deep sea. The transfer of particulate matter down to the deep is enhanced during atmosphere-driven, high-energy physical oceanographic processes like dense shelf water cascading (DSWC), which is caused by winter surface heat losses and evaporation. Here we present data from samples collected during winter 2012, when dense shelf water formation and subsequent cascading triggered the flushing of large amounts of PFASs through a submarine canyon to depths in excess of 1000 m. The finding of quantifiable concentrations of long-chain PFOA, PFOS and PFNA substances and significantly high concentrations of the short-chain substances PFHxA and PFBA indicates that these compounds, sorbed onto particulate matter, are quickly and directly transferred to the ocean's interior, thus highlighting the role of DSWC in removing those pollutants from the coastal ocean. Eventually, uncertainties about our results arising from the limited number of samples available are counterbalanced by their intrinsic value as intense DSWC events, like the one in 2012, occur only every 5-7 years in the study area, which seriously restricts sampling opportunities. Our results add PFASs to the list of persistent organic pollutants like polychlorinated biphenyls, chlorobenzenes or polycyclic aromatic hydrocarbons known to be conveyed to the deep marine environment.
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Affiliation(s)
- Anna Sanchez-Vidal
- GRC Geociències Marines, Departament d'Estratigrafia, Paleontologia i Geociències Marines, Universitat de Barcelona, Martí i Franquès s/n, 08028 Barcelona, Spain.
| | - Marta Llorca
- Departament de Química Ambiental, Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDAEA-CSIC), Jordi Girona 18-26, 08034 Barcelona, Spain
| | - Marinella Farré
- Departament de Química Ambiental, Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDAEA-CSIC), Jordi Girona 18-26, 08034 Barcelona, Spain
| | - Miquel Canals
- GRC Geociències Marines, Departament d'Estratigrafia, Paleontologia i Geociències Marines, Universitat de Barcelona, Martí i Franquès s/n, 08028 Barcelona, Spain
| | - Damià Barceló
- Departament de Química Ambiental, Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDAEA-CSIC), Jordi Girona 18-26, 08034 Barcelona, Spain
| | - Pere Puig
- Institut de Ciències del Mar (ICM-CSIC), Passeig Maritim de la Barceloneta 37-49, 08003 Barcelona, Spain
| | - Antoni Calafat
- GRC Geociències Marines, Departament d'Estratigrafia, Paleontologia i Geociències Marines, Universitat de Barcelona, Martí i Franquès s/n, 08028 Barcelona, Spain
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