ISTerre - Institut des Sciences de la Terre

Projet La PATCHAMAMA

Stéphane GUÉDRON — 2025-09-05T13:50:14Z

LA PATCHAMA : Lacs de l'Altiplano (Bolivie) : exploration in situ des Processus (A)biotiques contrôlant le biogéoCHimie Aquatique du Mercure A l'échelle MoléculAire et isotopique.

Durée : 2013 - 2016

Coordinateur : David Amouroux (LCABIE UMR5254)

Equipe ISterre impliquée :
– Géochimie 4D

Contact ISTerre : Stéphane Guédron

Collaborations :
– IPREM, UMR 5254 CNRS-UPPA,
– GET, UMR 234 IRD LA PAZ,
– BOREA, UMR 7208 MNHN - IRD,
– LEMARUMR 6539 CNRS-UBO-IRD

Pour étudier le devenir et les transformations des contaminants, la combinaison des approches moléculaires et multi isotopiques devrait fournir de nouvelles informations afin de mieux contraindre leur devenir biogéochimique et leur impact écotoxicologique. La composition isotopique spécifique des espèces (CSIA) peut également être pertinente pour quantifier les processus environnementaux et suivre les sources de pollution dans les écosystèmes complexes et donner une nouvelle dimension pour l'évaluation des risques pour l'environnement. Les progrès récents effectués dans la biogéochimie des isotopes stables du mercure (Hg) ont mis en évidence des variations significatives dans la composition isotopique naturelle du Hg et montrent un fort potentiel pour le traçage des sources de pollution et la quantification des transformations du Hg. Le principal objectif du projet ANR « La Pachamama » est de combiner pour la première fois les informations sur la spéciation moléculaire du mercure et sur la composition isotopique de ses composés, le méthylmercure (MeHg) et le mercure inorganique (IHg), ainsi que la mesure des transformations de ces formes chimiques (méthylation / déméthylation / réduction). Il est proposé que cette information permettra une meilleure compréhension des mécanismes complexes de régulation des formes toxiques et de leur transfert au niveau des différentes interfaces (sédiments / eau / air) et dans les réseaux trophiques. L'originalité de ce projet réside dans le fait que la plupart des expériences seront menées in situ et directement appliqués à l'hydrosystème emblématique des lacs « Titicaca - Uru Uru – Popoo » (Bolivie / Pérou), dans lequel différents gradients climatiques, hydrologiques et anthropiques permettront de fournir un ensemble de résultats innovants et fondamentaux, mais aussi des conclusions très pertinentes pour la gestion régionale de la pollution métallique dans les milieux aquatiques de la région de l'Altiplano. Ces écosystèmes lacustres extrêmes affichent des caractéristiques biogéochimiques uniques, tels que l'altitude élevée, la productivité biologique importante, les radiations UV intenses et les teneurs assez basses en oxygène des eaux de surface. Ces conditions sont susceptibles de stimuler de manière significative à la fois la production et la dégradation du MeHg, et son fractionnement isotopique dépendent ou indépendant de la masse. La stratégie scientifique et expérimentale est de se concentrer sur les études de processus menées sur le terrain par des approches pluridisciplinaires entre les problèmes biogéochimiques adressées comme suit : -Effectuer une première évaluation des sources de contamination du Hg et de son devenir dans l'hydrosystème du lac Titicaca. -Déterminer les facteurs physico-chimiques et hydrologiques influençant la formation, la dégradation et le fractionnement isotopique de méthylmercure. -Déterminer les facteurs écologiques et physico-chimiques qui influent sur la bioaccumulation, le transfert dans les réseaux trophiques et le fractionnement isotopique du méthylmercure -Intégrer l'information moléculaire et isotopique en relation avec les structures des écosystèmes aquatiques afin de fournir des outils d'évaluation des risques applicables à des problématiques locales et internationales.

Source

La PATCHAMAMA project

Anaïs SCHNEIDER, Stéphane GUÉDRON — 2013-11-10T10:50:00Z

La PATCHAMAMA : Lakes of the Altiplano (Bolivia) : in situ exploration of the (a)biotic Processes controlling the Aquatic biogeoCHemistry of Mercury At the Molecular and isotopic scAle

Duration : 2013-2016
Coordinator : David Amouroux (LCABIE UMR5254)
ISTerre research team involved : Geochemistry
ISTerre contact : Stéphane Guédron
Collaborations :

IPREM, UMR 5254 CNRS-UPPA,
GET, UMR 234 IRD LA PAZ,
BOREA, UMR 7208 MNHN - IRD,
LEMARUMR 6539 CNRS-UBO-IRD

To study the environmental chemistry and advanced transformations, combined molecular and multi isotopic signatures of contaminants should provide new information to better constrain their biogeochemical fate and ecotoxicological impact. The compound specific isotopic composition (CSIA) can also be relevant to quantify environmental processes and track pollution sources in complex ecosystems and provide a new dimension for environmental risk assessment. Recent advances in mercury (Hg) stable isotope biogeochemistry have demonstrated meaningful variations in natural Hg isotope composition and highlighted the potential for tracing sources and quantifying Hg transformations. The main objective of the ANR project "LA-PACHAMAMA" is to combine for the first time the information on the molecular speciation of Hg and on the isotopic composition of its related compounds, methylmercury (MeHg) and inorganic mercury (IHg), as well as the transformation extent of these chemical forms (methylation / demethylation /reduction). This new information may provide a better understanding of the complex mechanisms of regulation of toxic forms and their transfer at various interfaces (sediment / water / air) and within food webs. The originality of this project lies into the fact that most of the experiments will be conducted in situ, in the emblematic Peruvian/Bolivian hydrosystem “Titicaca - Uru Uru – Popoo”, in which different climatic, geochemical, hydrologic and anthropogenic gradients are expected to provide a set of novel and fundamental outcomes, but also highly relevant conclusions to the regional management of the metallic pollution in the Altiplano region. This extreme lake ecosystem displays unique biogeochemical features such as high altitude, significant productivity, high UV radiations and low oxygenated waters that are likely to stimulate significantly both the production and degradation of MeHg, and likely Mass Depedent and Mass Independent fractionation of Hg isotopes. The scientific and experimental strategy is to focus on process studies conducted in the field by multidisciplinary approaches among the biogeochemical problems addressed as follow :
– Perform a first assessment of Hg contamination source and fate in the lake Titicaca hydrosystem.
– Determine the physico-chemical and hydrological factors influencing the formation, degradation and isotopic fractionation of MeHg
– Determine the ecological and physico-chemical factors influencing the bioaccumulation, transfer and isotopic fractionation of MeHg in the foodwebs
– Integrate the molecular and isotopic information in relation to the aquatic ecosystem structures in order to provide risk assessment tools towards local and global perspectives.

– Source

INTERCONNECT project : Bioaccumulation of organometallic compounds in Tropical Chains

Anaïs SCHNEIDER, Stéphane GUÉDRON — 2012-11-05T15:15:58Z

Influences of INTERCONNECTIONS between terrestrial and aquatic environments on the bioaccumulation of organometallic compounds in the Tropical Chains

Duration : 2012 - 2015
Coordinator : Noureddine Bousserrhine
ISTerre team involved : Geochemistry
Contact at ISTerre : Stéphane Guédron
Collaborations :

UPPA – IPREMInstitut Pluridisciplinaire de Recherche en Environnement et Materiaux ;
LCELaboratoire Chrono-Environnement - Université de Franche-Comté ;
LGCgELaboratoire Génie Civil et géo-Environnement - Lille 1. Ecologie Numérique et Ecotoxicologie ;
INRA SAS Sol Agro et hydrosystème Spatialisation ;
BIOEMCOUMR 7618 CNRS-IRD-INRA-ENS-UP6-UPEC Bioemco Biogéochimie et écologie des milieux continentaux

Mercury is a natural component of the earth's crust and can be released into the environment. In addition to this natural source, there are also various anthropogenic sources. According to a report by the United Nations Environment Programme (2003), industrial activities are responsible for more than 70% of emissions into the atmosphere. Another source of pollution is its use for artisanal gold and silver mining in southern countries. Soils and sediments are recognized as the main storage compartments for mercury in terrestrial and aquatic ecosystems and its transfer to anaerobic aquatic environments can lead to bacterial methylation.

The biomagnification of the methyl mercury thus formed (the most toxic form) and its bioaccumulation along the food chains generate major environmental and health problems, which affect both tropical ecosystems and temperate urban areas. The risks associated with heavy metals in soils and sediments are highly dependent on their speciation and bioavailability, properties that are themselves controlled by the physico-chemical properties of soils, sediments and the action of ubiquitous engineering microorganisms and macroorganisms such as earthworms. Also, the bioavailability of mercury, which is rarely reported in the literature but is crucial to assess its toxicity, will depend on all biotic and abiotic factors capable of modifying its oxidation state as well as the stability of its carrier phases (iron oxides, organic matter).

By choosing mercury as a model contaminant, Guyana as a study site where mercury is a daily reality and a toposequence representative of soil distribution in this region (a continuum from well-draining soils (oxisols) at the top of the slope to a marine sedimentary environment) the INTERCONNECT project is organized around three actions (or worpackages) that propose the following approaches.

WP2 is interested in (1) characterizing the distribution of mercury according to soil and sediment characteristics, (2) identifying potential methylation niches, measuring the bioavailability of mercury WP3 is interested in (1) characterizing the actors of mercury biotransformation (methylation, demethylation, reduction) ; (2) quantify mercury (bio)transformation activities and highlight the role of the different functional groups involved ; (3) measure the in situ response of soil and sediment microorganisms and macro-organisms to the presence of mercurial compounds. WP4 is interested in highlighting the responses to mercury contamination at different cellular and molecular levels in two "macro-invertebrate" study models (earthworms, Chironoma).

This innovative project will therefore seek to highlight the succession of links and processes from a diagnostic stage of mercury in contrasting environments to the impact of its available fraction on the diversity of microbial communities and the physiology of model animals. This interconnection gives a multidisciplinary dimension that has led to the bringing together of specialists from complementary disciplinary fields (Pedology, Geochemistry, Biogeochemistry, Microbial ecology, Molecular ecology). Thus, this project should make it possible to better understand the fate of mercurial compounds, their impact on soil and sediment fauna, and to develop prediction tools concerning the modification of the fate of these contaminants in the sensitive area of French Guiana (and in Amazonia in general) in a global context of direct impacts through human activities and indirect impacts through global change.

– Source, ANR-11-CESA-0020

CV

Stéphane GUÉDRON — 2012-01-16T15:11:14Z

IRD researcher

Phone +33- 476 635 198 (office 142)
Email stephane.guedron ird.fr
Birth date : 01/16/1978, 2 child

Graduate

2023 Research director IRD (Institute of Earth Sciences / Univ. Grenoble Alpes)
2021 Habilitation à Diriger des Recherches (14.06.2021 - UGA)
Since 2011 Researcher IRD – Geochemistry team – ISTerre (UGA)
2008-2011 Post doctoral position – Limno-geochemistry (UNIGE- Forel institute)
2004-2007 PhD – Environmental geochemistry - University Grenoble Alpes (CNRS-CMB-UGA).
2002 Master - Soil Science – University Rennes (ENSAR-INRA).
2000 Bachelor – Earth and Universe Sciences- University Grenoble I (Université J.Fourier).

Skills

Analytical chemistry : CVAFS (THg), cryogenic – GC- CVAFS (MMHg – hydride generation and ethylation), AMA (Hg), ICP-AES, ICP-MS, ICP-AAS, LC-AFS (As), IRS (C), CM-CRDS (δ13C) .
Analytical physics : Laser Granulometry, X.R.D., B.E.M. and microprobe, optical microscopy, µXRF.
Specific sampling / filtration : Tangential Flow filtration, dialysis membranes (peepers), core slicing…
Langages : English, Spanish and French.

Scientific Projects

2023-2027
• LMI ALTIPLANO (2024-2029, IRD, PI) : Anthropogenic pressure, contaminants and water resource in the Andean Altiplano (Bolivia) : towards resilience strategies
• ANR ECLAT (2024-2027 – PI WP3) : Processes controlling the environmental dynamics and societal impacts of geogenic and anthropogenic trace metals contaminants in French Guiana
• Rehab & Odyssée (2022-2027 – Labex/CTG/ACE, PI) : Towards better goldmining practices : effect of rehabilitation on the reduction of Hg fluxes in French Guyana & western Africa (Burkina Faso and Guinea).

2021-2022
• PlomOs (EC2CO 2021-2022, co-PI) : Traçage isotopique des contaminations historique en Pb et de leurs impacts sanitaires
• Brome-X (Labex 2021-2022, co-PI) : Brome : nouvelles approches pour un proXy paléoenvironnemental
• EFFICACE (EC2Co 2021-2022, co-PI,) : Étude des Fluctuations des Flux d'air de l'Italie CentrAle à la Turquie de 15000 à 0 ka : interaCtions et dynamique des Eléments traces, de la végétation et du climat.

2017-2021
• Antibol (EC2Co, 2020/21) : fractionnement isotopique de l'antimoine : traçage de sources et processus
• PNUD (2020-2023 – co-PI) : Monitoreo y restauración del Lago Menor Titicaca.
• MITI/CNRS (2020-2023 – partner) : Projet CarMAlpes : Plasticité/adaptation de la Cardamine resedifolia aux gradients de pollutions Métalliques/HAP issus des activités minières dans les Alpes.
• AURA (2020-2023 – partner) : Projet région ; Traçage isotopique de l'origine des tuyauteries en Pb de la cité Antique de Vienne (Isère).
• EC2CO (2020-2022 – partner) : Projet AntiBol ; Développement du système isotopique 123Sb/121Sb pour le traçage de sources et de processus biogéochimiques dans les milieux aquatiques contaminés par l'activité minière et métallurgique en Bolivie.
2013-2017 (expatriation en Bolivie)
• Labex@osug2020 – PaleoSurLipez (2017-2018 – PI) : Reconstitution paléo-climatique et -écologique à haute résolution au cours de l'Holocène des lagunes du Sud de l'altiplano Bolivien (lagunes Verde, Blanca et Colorada).
• PIA-ACC Bolivia – COSUDE (2015-2017 – co-PI) - Indentificación de bioindicadores de cambio climático en lagos emblemáticos del Altiplano Boliviano”
• ANR La Patchamama (2013-2016 – PI WP 2)) : Lacs de l'Altiplano (Bolivie) : exploration des processus (a)biotiques in situ contrôlant la bio-géochimie aquatique du mercure à l'échelle moléculaire et isotopique.
• PaleoBol (2014 – 2018 - PI) : Reconstitution Paléo-environnemental à l'échelle de l'holocène des changements climatiques et des flux de métaux dans les archives sédimentaires du lac Titicaca (Bolivie).
• EC2CO PhytoBol (2014-2016 – CoPI) : Phytoremédiation des eaux contaminées en entrée des lacs Titicaca et Uru Uru en Bolivie.
• Labex@osug2020 - Tracisomer (2015 – 2017 - PI) : Traçage isotopique des sources et flux de mercure dans le continuum Rio Katari – lac Titicaca (Bolivie)

2011-2013
• Mezquital valley project - Mexican PAPIIT program – (ISTerre/IRD - UNAM university – LTHE/IRD)
Mercury and arsenic transfer and fate in soils irrigated by the waste waters of Mexico city.
2009-2011
• Asia-Link Programme (Phase III) - European Commission – CALIBRE (Cambodia And Laos Initiative for Building human Resources for the Environment) - Courses and field training for geochemical analysis of waters – Research : As and Hg contamination of ground and surface waters in Lao PDR.
• Sino-Swiss Joint Research Projects : The Distribution, Methylation, and Bioaccumulation of Mercury in Sediments of Baihua Reservoir in Guiyang, China.
2008-2010
• Nation Swiss funds research projects (FNRS) : Mobility and bioavailability of metals in continental waters ; an integrated approach – Part 4 : narrowing the laboratory vs. field gap.
• Bay of Vidy (Lake Geneva, Switzerland) : geochemistry of Hg and MMHg in the water column, sediment porewaters and Hg bioaccumulation in Chironomus Riparius.
• Venice lagoon (Italy) : Bioaccumulation of mercury in benthic invertebrates of the Venice Lagoon.
• Czorsztyn reservoir (Poland) – Chromium speciation in the waters, colloids and sediments porewaters.
2007
• PhD CIFRE CMB-CNRS (10/2004-10/2007) – direction : A. Pavé, L. Charlet, M. Grimaldi et D. Cossa ; « Impact of former goldmining on mercury fluxes towards aquatic ecosystems in French Guiana »
Collaboration : Boulanger Goldmining Compagny, French Guiana CNRS, LGIT (CNRS-UJF), IRD Bondy.
2004

Fonctions administratives & comités scientifique

• 2019-2024 : Membre du comité du PSIP/CoSav GeoD de l'IRD
• 2019-2024 : Responsable de l'équipe Géochimie ISTerre
• 2019-2021 : Co-porteur de la JEAI TITICACA avec Dario Acha (UMSA-Bolivie)
• 2019-2021 : Membre du GDR LiGA (Groupement de recherche Littoral de Guyane sous influence amazonienne)
• 2019-2024 : Membre de l'atelier Géochimie de la commission de l'OSUG
• Depuis 2019 : Membre des comités d'évaluation
o Projets FONDECYT/CONICYT (Comisión Nacional de Investigación Científica y Tecnológica – Chile)
o Programme doctoral du BRGM (évaluation de propositions de sujet de thèse)
• 2016-2020 : Membre de la commission scientifique sectorielle (CSS1) de L'IRD
• 2017 : Membre de l'instance intersectorielle CSS-CS pour l'évaluation des Laboratoires mixtes internationaux
• Responsable du parc analytique mercure et δ13C de l'équipe géochimie d'ISTerre

Organisation d'évènements scientifiques et valorisation de la recherche

• Organisateur de l' International colloquium on current and ancient contamination in Andes aquatic ecosystems, (La Paz – Bolivia May 2016)
• Co-organisateur Atelier transversal « SOLS » de l'OSUG (Grenoble, 30.03.2012)
• Co-organisateur du Forel symposium 2010 - Frontiers in Lake research (Geneva, 17-18.09.2010)

Teaching (Licence, Master, Doctorat)

• Chimie de l'environnement / Cycles biogéochimique / Chimie des interfaces & transfert réactif
• Etudes paléo-environnementales : tourbières et lacs
• Modélisation environnementale /Analyse systémique

Publication list

Stéphane GUÉDRON — 2012-01-16T15:11:04Z

Accepted Publications

– 60 - Vella M.A., Bièvre G., Delaere C., Thiesson J., Guérin R., Rivera-Casanovas C. and Guédron S., 2024. The hydraulic network of the pre-Hispanic city of Tiwanaku (Bolivia) : New insights from the integration of canal morphology, hydrogeological and palaeoenvironmental data. Quaternary Science Reviews. 324, 108475.

– 59 - Cossa, D., Guédron, S., Coquery, M., Calafat, A., Zuñiga, D., Stavrakakis, S., Radakovitch, O., Buscail, R., García-Orellana, J., Heussner, S., 2023. Mercury deposition in the Eastern Mediterranean : Modern fluxes in the water column and Holocene accumulation rates in abyssal sediment. Chem. Geol., 121652.

– 58 - Ziegler Rivera F. R. A., Prado Pano B., Guédron S., Mora Palomino L., Ponce de León Hill C., and Siebe Grabach C., 2023. Impact of the change in irrigation practices from untreated to treated wastewater on the mobility of potentially toxic elements (PTEs) in soil irrigated for decades. J Soils Sediments. 23, 2726–2743.

– 57 - Guédron S., Delaere, C., Fritz, S.C., Tolu, J., Sabatier, P., Develle, A.-L., Heredia, C., Vérin, C., Alves, E.Q., and Baker, P.A. Holocene variations in Lake Titicaca water level and their implications for sociopolitical developments in the central Andes. Proc. Natl. Acad. Sci. USA, 2023 ; 120 (2), e2215882120.

– 56 - Robles, M., Peyron, O., Ménot, G., Brugiapaglia, E., Wulf, S., Appelt, O., Blache, M., Vannière, B., Dugerdil, L., Paura, B., Ansanay-Alex, S., Cromartie, A., Charlet, L., Guédron, S., de Beaulieu, J.L., Joannin, S., 2023. Climate changes during the Lateglacial in South Europe : new insights based on pollen and brGDGTs of Lake Matese in Italy. Clim. Past. 19(2), 493-515.

– 55 - Tisserand, D., Guédron S., Viollier E., Jézéquel D., Rigaud S., Campillo S., Sarret G., Charlet L., and Cossa D. Mercury, organic matter, iron, and sulfur co-cycling in a ferruginous meromictic lake. Applied Geochemistry, 2022 ; 146, 105463.

– 54 - Heredia, C., Guédron, S., Point, D., Perrot, V., Campillo, S., Verin, C., Espinoza M.E., Fernandez, P., Duwig, C., and Achá, D. Anthropogenic eutrophication of Lake Titicaca (Bolivia) revealed by carbon and nitrogen stable isotopes fingerprinting. Science of the Total Environment, 2022 ; 845 : 157286.

– 53 - Chaboche, P-A, Pointurier, F, Sabatier, P., Foucher, A., Tiecher, T., Minella, J.P.G., Tassano, M., Hubert, A., Morera, S., Guédron, S., Ardois, C., Boulet, B., Cossonnet, C., Cabral, P., Cabrera, M., Chalar, G., and Evrard, O. 240Pu/239Pu signatures allow refining the chronology of radionuclide fallout in South America. Science of the Total Environment, 2022 ; 843 : 156943.

– 52 - Delaere, C. and Guédron S., 2022. The altitude of the depths : use of inland water archaeology for the reconstruction of inundated cultural landscapes in Lake Titicaca. World Archaeology. 54(1), 67-83.

– 51 - Bouchet, S., Tessier, E., Masbou, J., Point, D., Lazzaro, X., Monperrus, M., Guédron, S., Acha, D., Amouroux, D., 2022. In Situ Photochemical Transformation of Hg Species and Associated Isotopic Fractionation in the Water Column of High-Altitude Lakes from the Bolivian Altiplano. Environmental Science & Technology, 56, (4), 2258-2268.

– 50 - Jiskra, M., Guédron, S., Tolu, J. ; Fritz, S., Baker, P., Sonke, J., 2022. Climatic controls on a Holocene mercury stable isotope sediment record of Lake Titicaca. ACS Earth and Space Chemistry, 6, (2), 346-357.

– 49 - Cossa D., Mucci A., Guédron S., Coquery M., Radakovich O., Escoube R., Campillo S., and Heussner S., 2021 Mercury accumulation in the sediment of the Western Mediterranean abyssal plain : A reliable archive of the late Holocene. Geochimica et Cosmochimica Acta, 10.1016/j.gca.2021.06.014

– 48 Guédron S. and Acha D., 2021. Mercury and Methylmercury Contamination of Terrestrial and Aquatic Ecosystems. Editorial letter. Appl. Sci. 2021, 1202794

– 47 Tisserand, D., Guédron S., Razimbaud S., Findling N. and Charlet L., 2021. Acid volatile sulfides and simultaneously extracted metals : A new miniaturized ‘purge and trap' system for laboratory and field measurements. Talenta, 122490.

– 46 Guédron, S., Tolu, J., Delaere, C., Sabatier, P., Barre, J., Heredia, C., Brisset, E., Campillo, S., Bindler, R., Fritz, S.C., Baker, P.A., Amouroux, D., 2021. Reconstructing two millennia of copper and silver metallurgy in the Lake Titicaca region (Bolivia/Peru) using trace metals and lead isotopic composition. Anthropocene, 100288.

– 45 Quiroga-Flores, R., Guédron S. and Achá, D. 2021, High methylmercury uptake by green algae in Lake Titicaca : potential implications for remediation. Ecotoxicology and Environmental Safety, 207, 111256.

– 44 Guédron S., Acha D., Bouchet S., Point D., Tessier E., Heredia C., Rocha S., Fernandez Saavedra P., Flores M., Bureau S, Quino-Lima I., and D. Amouroux, 2020. Accumulation of Methylmercury in the High-Altitude Lake Uru Uru (3686 m a.s.l, Bolivia) Controlled by Sediment Efflux and Photodegradation. Appl. Sci. 2020, 10, 7936.

– 43 Guédron S., Audry S., Acha D., Bouchet S., Point D., Condom T., Heredia C., Campillo S., Baya P. A., Groleau A., Amice E. and D. Amouroux, 2020. Diagenetic production, accumulation and sediment-water exchanges of methylmercury in contrasted sediment facies of Lake Titicaca (Bolivia). Science of the Total Environment, 2020 ; 723 (2020), 138088.

– 42 Elbaz-Poulichet F., Guédron S., Develle A.-L., Freydier R., Perrot V., Rossi M., Piot C., Delpoux S., and Sabatier P. 2020. A 10,000-year record of trace metal and metalloid (Cu, Hg, Sb, Pb) deposition in a western Alpine lake (Lake Robert, France) : deciphering local and regional mining contamination. Quaternary Science Reviews, 228 (2020) 106076.

– 41 Sarret G., Guédron S., Acha D., Bureau S., Arnaud-Godet F., Tisserand D., Goni-Urriza M., Gassie C., Duwig C., Proux O. and Aucour A.M. Extreme Arsenic Bioaccumulation Factor Variability in Lake Titicaca, Bolivia", Scientific Reports, 2019 ; 9 : 10626.

– 40 Niane, B., Guédron, S., Feder F., Legros S., Ngom, P., and Moritz, R.. Impact of recent artisanal small-scale gold mining in Senegal : mercury and methylmercury contamination of terrestrial and aquatic ecosystems. Science of the Total Environment, 2019 ; 669, 185-193.

– 39 Guédron, S., Tolu, J., Brisset, E., Sabatier, P., Perrot, V., Bouchet, S., Develle, A.L., Bindler, R., Cossa, D., Fritz, S.C., and Baker P.A. 2019. Late Holocene volcanic and anthropogenic mercury deposition in the western Central Andes (Lake Chungará, Chile). Science of the Total Environment, 2019 ; 662, 903-914.

– 38 Achá D., Guédron S., Amouroux, D., D. Point, Lazarro X., P.E. Fernandez and Sarret G. 2018. Algal bloom exacerbates hydrogen sulfide and methylmercury contamination in the emblematic high-altitude Lake Titicaca. Geosciences 2018, 8(12), 438.

– 37 Guédron S., Escobar-Torrez K., Ledru M.P. and Brisset E. 2018. Enhanced mercury deposition by Amazonian orographic precipitation : evidence from high-elevation Holocene records of the Lake Titicaca region (Bolivia). Palaeogeography, Palaeoclimatology, Palaeoecology, DOI : 10.1016/j.palaeo.2018.09.023.

– 36 Guédron S., Amouroux, D., Tessier E., Grimaldi C., Barre J., Berail, S.., Perrot V. And Grimaldi M., 2018. Mercury isotopic fractionation during pedogenesis in a tropical forest soil catena (French Guiana) with consideration of historical goldmining. Environmental Science and Technology, DOI : 10.1021/acs.est.8b02186.

– 35 S. Bouchet, M. Goñi-Urriza, M. Monperrus, R. Guyonneaud, P. Fernandez, C. Heredia, E. Tessier, C. Gassie, D. Point,, S. Guédron, D. Achá, D. Amouroux, 2018. Linking microbial activities and low molecular weight thiols to Hg methylation in biofilms and periphytons from high altitude tropical lakes (Bolivian altiplano). Environmental Science and Technology, , DOI : 10.1021/acs.est.8b01885.

– 34 Cossa, D., Fanget A.-S., Chiffoleau J.-F., , Bassetti M.-A., Buscail R., Deninelou B., Briggs K., Arnaud M., Guédron S. and Berné, S. 2018. Chronology and sources of trace elements accumulation in the Rhône pro-delta sediments (Northwestern Mediterranean) during the last 400 years. Progress in Oceanography, 163, 161-171.

– 33 Cossa D., Durrieu de Madron X., Schafer J., Guédron S., Marusczak N., Castelle S. and Naudin J.J. 2018. Sources and exchanges of mercury in the waters of the Northwestern Mediterranean margin. Progress in Oceanography, 163, 172-183.

– 32 Molina C.I., Lazzaro, X., Guédron, S., & Achá D., 2017. Contaminación de la bahía de Cohana, Lago Titicaca : desafíos y oportunidades para promover su recuperación. Editorial letter of Revista Ecología en Bolivia (www.ecologiaenbolivia.com).

– 31 Guédron S., Point D., Acha D., Bouchet S., Baya P. A., Tessier E., Monperrus M., Molina C.I., Groleau A. , Chauvaud L., Thebault J., Amice E., Alanoca L., Duwig C. , Uzu G., Lazarro X. , Bertrand A., Bertrand S. , Barbraud C., Delord K., Gibon F.M., Ibanez C., M. Flores, Fernandez Saavedra P., Ezpinoza M.E., Heredia C. , Rocha F., Zepita C., and D. Amouroux, 2017. Mercury contamination level and speciation inventory in the hydrosystem of Lake Titicaca : current status and future trends. Environmental Pollution, 231, 262-270.

– 30 Weide, M., Fritz, S, Hastorf, C., Bruno M., Baker, P., Guédron, S., and Salenbien, W., 2017. A 6000 yr diatom record of mid-to late Holocene fluctuations in the level of Lago Winaymarca, Lake Titicaca (Peru/Bolivia). Quaternary Research : 1-14.

– 29 Charlet, L., Blancho, F., Bonnet, T., Garambois, S., Boivin, P., Ferber, T., Tisserand, D., Guédron, S., 2017. Industrial Mercury Pollution in a Mountain Valley : A Combined Geophysical and Geochemical Study. Proc. Earth and Planetary Sci. 17, 77-80.

– 28 Strady E., Tuc Dinh Q., Némery J., b, Nguyen T.N., Guédron S., Nguyen N.S., Denis H., and Nguyen P.D., 2017. Spatial variation and risk assessment of trace metals in water and sediment of the Mekong Delta. Chemosphere, 179 : 367- 378.

– 27 Archundia D., Duwig C., Spadini L., Uzu G., Guédron S., Morel M.C., Cortez R., Ramos O., Chincheros J. and Martins J.M.F., 2017. How uncontrolled urban expansion increases the contamination of the Titicaca lake basin (El Alto - La Paz, Bolivia). Water, Air, & Soil Pollution, 228 (1), 44.

– 26 Cossa D., Durrieu de Madron X., Schafer J., Lanceleur L., Guédron S., Buscail R., Thomas B., Castelle S., Naudin J.J., 2017. The open sea as the main source of methylmercury in the water column of the Gulf of Lions (Northwestern Mediterranean margin). Geochimica et Cosmochimica Acta, 199, 222-237.

– 25 Strady, E., Hanh D.V.B., Nemery J., Guédron S., Tuc D.Q., Denis H., Dan N. P., 2016. Baseline seasonal investigation of nutrients and trace metals in surface waters and sediments along the Saigon River basin impacted by the megacity of Ho Chi Minh (Vietnam). Environmental Science and Pollution Research, 24(4), 3226-3243.

– 24 Alanoca L., Guédron S., Amouroux D., Audry S., Monperrus M., Tessier E., Goix S., Acha D., Seyler P. and Point D., 2016. Synergistic effects of mining and urban effluents on the level and distribution of methylmercury in a shallow aquatic ecosystem of the Bolivian Altiplano. Environmental Science : Processes & Impacts. 18, 1550 - 1560.

– 23 Guédron S., Amouroux, D., Sabatier P., Desplanque C., Develle A-L., Barre J., Feng C., Guiter F., Arnaud F., Reyss J-L. And Charlet L., 2016. A hundred year record of industrial and urban development in French Alps combining Hg accumulation rates and isotope composition in sediment archives from Lake Luitel. Chemical Geology : 431 : 10-19.

– 22 Schreck E., Sarret G., Oliva P., Calas A., Sobanska S., Guédron S., Barraza F., Point D., Huayta C., Couture R.M., Prunier J., Henry M., Tisserand D., Goix S., Chincheros J., Uzu G., 2016. Is Tillandsia capillaris an efficient bioindicator of atmospheric metal and metalloid deposition ? Insights from five months of monitoring in an urban mining area, Ecological Indic., 67 : 227-237.

– 21 Gimbert, F., Geffard, A., Guédron, S., Dominik, J. and Ferrari, B., 2016. Mercury tissue residue approach in Chironomus riparius : involvement of toxicokinetics and comparison of subcellular fractionation methods. Aquatic Toxicology, 171 : 1-8.

– 20 Guédron S., Devin S., Vignati D.A.L. Total and methylmercury partitioning between colloids and true solution : From case studies in sediment overlying and pore waters to a generalized model. Environmental Toxicology and Chemistry 2016, 35 : 330-339.

– 19 Hellal J., Guédron S., Huguet L., Schaefer J., Laperche V., Joulian C., Lanceleur L., Burnol A., Ghestem J-P., Garrido F., Battaglia-Brunet F. Mercury mobilization and speciation linked to bacterial iron oxide and sulfate reduction : A column study to mimic reactive transfer in an anoxic aquifer. Journal of Contaminant Hydrology 2015 ; 180 : 56-68.

– 18 Grimaldi M, Guédron S, Grimaldi C, 2015. Impact of gold mining on mercury contamination and soil degradation in Amazonian ecosystems of French Guiana. In : Brearley FQ, Thomas, A. D., editor. Land-use change impacts on soil processes : tropical and savannah ecosystems. CABI, Wallingford, UK, pp. 95-107.

– 17 Garcia Bravo A., Bouchet S., Guédron S., Amouroux D., Dominik J., Zopfi J. High methylmercury production under iron-reducing conditions in sediments impacted by sewage treatment plant discharges. Water Research 2015 ; 80 : 245-255.

– 16 Niane, B., Guédron S., Moritz R., Ngom P. M., Pfeifer H-R., Mall I. and Poté J., 2014. Human exposure to mercury in artisanal small-scale gold mining areas of Kedougou region, Senegal as a function of occupational activity and fish consumption. Environmental Science and Pollution Research, 1-11.

– 15 Guédron S, Duwig C, Prado BL, Point D, Giovana Florese M, Siebe C., 2014 -(Methyl)Mercury, Arsenic, and Lead Contamination of the World's Largest Wastewater Irrigation System : the Mezquital Valley (Hidalgo State—Mexico). Water, Air, & Soil Pollution, 225(8).

– 14 Niane, B., Moritz R., Guédron S., Ngom P. M., Pfeifer H-R., Mall I. and Poté J., (2014). Effect of recent artisanal small-scale gold mining on the contamination of surface river sediment : case of Gambia River, Kedougou region, southeastern Senegal. J. Geochem. Explo., 144, Part C(0) : 517-527.

– 13 Guédron S., Tisserand D., Garambois S, Molton F., Spadini L., Bounvilay, B., Charlet L., and Polya D. (2014). Baseline investigation of (methyl)mercury in waters, soils, sediments and key foodstuffs in the Lower Mekong Basin : the rapidly developing city of Vientiane (Lao PDR). J. Geochem. Explo, 143(0) : 96-102..

– 12 Guédron, S., Grangeon, S., Jouravelle G., Charlet C. and Sarret, G., (2013). Atmospheric mercury incorporation in soils of an area impacted by a chlor-alkali plant (Grenoble, France) : contribution of canopy uptake. Science of the Total Environment. 45-446, 356-364.

– 11 Guédron, S., Huguet, L., Vignati, D.A.L., Liu, B., Gimbert, F., Ferrari, B.J.D., Zonta, R., Dominik, J., (2012). Tidal cycling of mercury and methylmercury between sediments and water column in the Venice lagoon (Italy). Marine Chemistry, 130-131(0), 1-11..

– 10 Liu, B., Yan, H., Wang, C., Li, Q., Guédron, S., Spangenberg, J. E., Feng, X. and Dominik, J. 2012 - Insights into low fish mercury bioaccumulation in a mercury-contaminated reservoir, Guizhou, China. Environmental Pollution, 160(0) : 109-117.

– 9 Grangeon, S., Guédron, S., Asta, J., Sarret, G. and Charlet L. 2012 - Lichen and soil as indicators of an atmospheric mercury contamination in the vicinity of a chlor-alkali plant (Grenoble, France). Ecological Indicators, 13, 178-183.

– 8 Guédron S., Grimaldi M., Cossa D., Grimaldi C., Tisserand D. and Charlet L. 2011 - Methyl mercury formation in Amazonian soils : Evidence from a former gold-mined watershed of French Guiana Water Research, 45(8) : 2659-2669.

– 7 Guédron S., Cossa D., Grimaldi M. and Charlet L., 2011. Methylmercury in tailing ponds of Amazonian gold mines (French Guiana) : Field observations and effects of an experimental flocculation method for remediation. Appl. Geochem., 26(2) : 222-229.

– 6 Thevenon, F., Guédron, S., Chiaradia, M., Loizeau, J.L. and Poté J. 2011. (Pre-) Historic changes in natural and anthropogenic heavy metals deposition inferred from two contrasting Swiss Alpine lakes. Quaternary Sci. Rev., 30(1-2) : 224-233.

– 5 Vignati D.A.L., Guédron S. and Loizeau J.L., 2010. Practical work on basic physico-chemical water quality parameters during field courses. NEAR Curriculum in Natural Environment. Science, Terre et Environnement, Vol. 88, 223–229, ISBN 2–940153–87–6.

– 4 Guédron S., Grangeon S., Grimaldi M., and Lanson B., 2009. Mercury speciation in a tropical soil association ; Consequence of gold mining on Hg distribution in French Guiana. Geoderma 2009 ; 153 : 331-346.

– 3 Grimaldi C., Guédron S., and Grimaldi M., 2008. Mercury distribution in tropical soil profiles related to origin of mercury and soil processes. Science of the Total Environment, 401, pp 121-129.

– 2 Guédron S., Grimaldi C., Chauvel C., Spadini L. and Grimaldi M, 2006. Weathering versus
atmospheric contributions to mercury contents in French Guiana soils. Applied Geochemistry, 21, pp 2010-2022.

– 1 Guédron S., Grimaldi C., Chauvel C., Spadini L. et Grimaldi M, 2003. Determination of mercury atmospheric origin in French Guianese soils. J. Physique IV, 107, Vol. 1, pp 585-588.

Conference acta

Stéphane GUÉDRON — 2012-01-16T15:10:57Z

Conference Acta

– C. Heredia, A. T. Gourlan, B. Helly, H. Delile, G. Granier, A.Labouré, L. Audin, and S. Guédron. Lead and copper isotopic tracing of human exposure and ore sources during Roman mining activities in the ancient city of Vienne (Isère, France). Goldschmidt Conférence, Lyon, France, 4 - 9 July 2021.

– Guédron S. Mercury deposition during the Holocene in the Andes : Deciphering climatic and anthropogenic contribution. Conference invitee. March 11th 2021, Analytical, Environmental & Geo-Chemistry, Vrije Universiteit Brussel.

– Vella M.A., Bièvre G., Delaere C., Thiesson J., Guérin R. Heredia C. and Guédron S. Le réseau hydraulique de la cité pré-Inca de Tiwanaku (Bolivie) : mise en relation de la morphologie des canaux avec le contexte hydrogéologique et paléoenvironnemental. 27ème édition de la Réunion des Sciences de la Terre (RST). 2020, Lyon, France, October 26-30 2020.

– F. Arnaud, P. Sabatier, A. Leloup, A. Servettaz, B. Moine, A.-L. Develle, S. Guédron, V. Perrot, J. Poulenard, B. Fanget, E. Malet, E. Storen, J.-L. Reyss, N. Le Viavan, K. Heirman, M. De Batist, E. Michel, J.-L. de Beaulieu, N. Vanderputten, J. Bakke. Etablishing the first continuous Holocene tephrostratigraphy on Kerguelen Archipelago, subantarctic Indian Oean. EGU General Assembly 2020, SSP3.1 – Limnogeology - reading the geological record of lakes May 3-8, 2020.

– Tisserand D., Cossa D., Guédron S, Jézéquel D., Viollier E., Perrot V., Rigaud S., Campillo S. , Bureau S., Sarret G. and Charlet L. Mercury partition at the oxic/anoxic transition of a meromictic lake (Lake Pavin, Massif Central, France). Poster presentation at 14th International Conference on Mercury as a Global Pollutant – Krakow, Poland, September 8-13, 2019.

– Guédron S. Tolu J., Perrot V., Acha, D. and Brisset E., Holocene reconstruction of Hg deposition in the central Andes :
respective contribution of climate change, volcanism and anthropogenic activities : oral presentation at 14th International Conference on Mercury as a Global Pollutant – Krakow, Poland, September 8-13, 2019.

– Ramos A., Acha D., Lazzaro X., Guédron S, and Sarret G.., Periphyton is a haven for mercury accumulation and algal diversity at high altitude environments. Poster presentation at 14th International Conference on Mercury as a Global Pollutant – Krakow, Poland, September 8-13, 2019.

– Guédron S. Tolu J., Tessier E., Bueno, M., Mestrot A., Acha, D. and Amouroux, D. Insights into the speciation of Arsenic, Selenium and Mercury in saline lakes of the Bolivian Altiplano. Goldschmidt conference 2019 ; Barcelona August 18-23.

– Sarret G., Guédron, S., Acha D., Goni-Urriza, M. and Aucour, AM. As accumulation and changes in speciation in periphytic biofilms, Goldschmidt conference 2019 (session 12f), Barcelona August 18-23.

– Guédron S. Tolu J., Perrot V. and Brisset E. Holocene reconstruction of Hg deposition in the central Andes : respective contribution of climate change, volcanism and anthropogenic activities, oral presentation at 14th International Conference on Mercury as a Global Pollutant – Krakow, Poland, September 8-13, 2019.

– Bennavente, C., Combey, A., Walker, R., Garcia, B., Rosell, L., Aguirre, E., Rodriguez-Pascua, M.A., Grutzner, C., Guédron, S., and Sabatier, P., 2018. Archeoseismology in Machu Picchu, Paleoseismology and Lacustrine records in Cuzco region as key interdisciplinary approaches for intraplate deformation characterization on the Andean Altiplano. Oral presentation 6th Colloquium on historical earthquakes & paleoseismology studies ; Thursday, 25 October 2018 13:40.

– Duwig C., Archundia D., Uzu G., Guédron S., Ramos Ramos O., 2018 : Consecuencias de la fuerte antropización en los recursos hídricos de la cuenca Katari. Coloquio internacional en el marco de los 50 años del IRD en Bolivia : “Vulnerabilidad de los recursos hídricos en la cuenca Katari”, UMSA, La Paz, March 28, 2018.

– Ormachea M., Alanoca L., Huallpara L. and Guédron S.. Efectos de la actividad minera sobre el sistema hídrico de Milluni. Coloquio : “Vulnerabilidad de los recursos de agua en la subcuenca Katari del Lago Titicaca (Altiplano Norte, Bolivia)”, 28-29 Marzo 2018, UMSA, La Paz Bolivia.

– M. Jiskra, S. Guédron, J. Tolu, S. Fritz, P. Sabatier, P. Baker and J. Sonke. Atmospheric mercury deposition to a Holocene sediment record of Lake Titicaca investigated by Hg stable isotopes. BG1.4 – Mercury through time – Reconstructions of Hg deposition on different timescales using natural archives. Poster presentation EGU, Vienna Austria, 8–13 April 2018.

– J. Tolu, S. Bouchet, A. G. Bravo, J. Rydberg, C. Meyer-Jacob, S. Guédron, E. Brisset, E. Björn, S. Bertilsson, L. Winkel and R. Bindler. Characterizing the molecular composition of organic matter for process-understanding of trace metals fate in environmental systems. The International Conference on the Biogeochemistry of Trace Elements ICOBTE, ETH Zurich, Switzerland, July 16-20, 2017

– S. Guédron, S. Audry, D. Acha, C. Heredia, S. Bouchet, D. Point, J. Thébault, L. Chauvaud and D. Amouroux. Methylmercury production in surface sediments and exchanges with overlying water of Lake Titicaca (Bolivia). Poster presentation at the 13th International Conference on Mercury as a Global Pollutant – Providence, Rhode Island, July 16-21, 2017.

– S. Guédron, J. Tolu, E. Brisset, P.Sabatier, A.L. Develle, S. Bouchet, R. Bindler, A. I. Domic, S. C. Fritz and P.A. Baker. Late Holocene mercury deposition history in Lake Chungará (4500 m a.s.l., Chile) : Influence of volcanic eruptions and changes in paleolimnoecology. Oral presentation - 13th International Conference on Mercury as a Global Pollutant – Providence, Rhode Island, July 16-21, 2017.

– E. Tessier, D. Amouroux, Y. Colin, S. Guédron, M. Monperrus, M.S. Goni and R. Guyoneaud. Methylmercury formation and mobilization in tropical soils from a rainforest watershed (French Guiana). Poster presentation at the 13th International Conference on Mercury as a Global Pollutant – Providence, Rhode Island, July 16-21, 2017.

– D. Acha. S. Guédron, D. Point, D. Amouroux, P. Fernandez, S. Bouchet and X. Lazzaro. Eutrophication and algae blooms may have similar effects on methylmercury accumulation at high altitude sulfate-rich environments. 13th International Conference on Mercury as a Global Pollutant – Providence, Rhode Island, July 16-21, 2017.

– S. Bouchet, D. Amouroux, M. Goni, M. Monperrus, R. Guyoneaud, C. Heredia, E. Tessier, D. Point, S. Guédron and D. Acha. Linking microbial activity and Hg bioavailability to Hg methylation in Lake Titicaca hydrosystem (Bolivian Altiplano). Poster presentation at the 13th International Conference on Mercury as a Global Pollutant – Providence, Rhode Island, July 16-21, 2017.

– L. Alanoca, S. Guédron , M. Monperrus, D. Amouroux, E. Tessier, P. Seyler, M. Goni, R. Guyoneaud, D. Acha , S. Audry, M. E. Garcia, J. Quintanilla and D. Point. Biogeoquímica del mercurio en el lago tropical de altura Uru Uru (Altiplano boliviano). International colloquium on current and ancient contamination in Andes aquatic ecosystems, La Paz – May 3– 5, 2016, pp : 11.

– D. Amouroux, D. Point, S. Guédron, D. Acha, X Lazzaro, L. Chauvaud, S. Bouchet, A. Baya, M. Monperrus, E. Tessier, R. Guyoneaud, M. Goni, J. Thebault, A. Groleau, A. Lorrain, E. Amice, T. Lebec, S. Rocha, C. Heredia, M-E. Espinoza, M. Flores & R. Katari. Processes controlling Methyl-Hg formation and degradation in Lake Titicaca hydrosystem (Bolivian Altiplano). International colloquium on current and ancient contamination in Andes aquatic ecosystems, La Paz – May 3– 5, 2016, pp : 12.

– S. Guédron, S. Audry, D. Acha & D. Amouroux. Methylmercury production and exchanges in sediments of Lake Titicaca. International colloquium on current and ancient contamination in Andes aquatic ecosystems, La Paz – May 3– 5, 2016, pp : 13.

– D. Achá Cordero, C. Heredia, P. Fernandez, M-E. Espinosa, D. Point, S. Guédron, A. Groleau, D. Amouroux, J. Nuñez, G. Lora and X. Lazzaro. New lights on Lake Titicaca eutrophication process and perspectives about monitoring and remediation. International colloquium on current and ancient contamination in Andes aquatic ecosystems, La Paz – May 3– 5, 2016, pp : 16.

– X. Lazzaro, H. Rybarczyk, T. Meziane, C. Hubas, D. Lamy,D. Point, J.M. Martine, S. Guédron, C. Duwig, A. Groleau, S. Rocha Lupa, M.P. Alcoreza Ortiz, W.G. Lanza Aguiar, A.J. Flores, E.Z. Loyza Torrico, C. Ibañez Luna, J. Nuñez Villalba, C. Gamarra Peralta, C. Villanueva Quispe, L. La Cruz, V. Villafañe, W. Helbling, A. Lebourges-Dhaussy, J. Guillard, I. Domaizon, C. Kruk, N. Mazzeo, M. Meerhoff, M. Pereira Sandoval, J. Delegido, A. Ruiz, J. Moreno, C. Molina Arzabe & D. Achá Cordero. Accelerated eutrophication in Lake Titicaca : Historical evolution, mechanisms, monitoring, and observatory approach. International colloquium on current and ancient contamination in Andes aquatic ecosystems, La Paz – May 3– 5, 2016, pp : 22-23.

– J. Tolu, S. Guédron, E. Brisset, R. Bindler, P.A. Baker and S.C. Fritz. Multi-proxy reconstruction of changes in water level and organic matter sources related to climate change over the Holocene (Lake Titicaca, Bolivia). .International colloquium on current and ancient contamination in Andes aquatic ecosystems, La Paz – May 3– 5, 2016, pp : 33.

– L. Charlet, F. Blancho, T. Bonnet, P. Boivin, T. Ferber, D. Tisserand, S. Guédron. 2016. Industrial mercury pollution in a mountain valley : a combined geophysical and geochemical study. 15th Water-Rock Interaction International Symposium, Evora, Portugal (16-21.10.2016).

– Weide, D. M., Fritz, S., Hastorf, C., Salenbien, W., Baker, P. and Guédron S., 2015. A Late Holocene Lake Level Reconstruction of Lago Huiñaimarca, Southern Lake Titicaca, Peru/Bolivia. Sixth International Limnogeology Congress - Reno, Nevada, USA (06.2015).

– Guédron, S., Amouroux, D., Tessier, E., Grimaldi, M., Grimaldi, C., Feng, C., Barre, J., Berail, S. and Bousserrhine, N., 2015. Tracing Hg transport, reaction and contamination source using Hg isotopes in tropical forest soils affected by ancient gold mining activity (French Guiana), oral presentation. International Conference on Mercury as a Global Pollutant- Jeju, Corea (06.2015).

– Colin Y., Tessier E., Monperrus M., Bertin P., Goni M. S., Amouroux D., Guédron S., Guyoneaud R., 2015. Microbial communities linked with mercury methylation and demethylation processes in French Guyana soils, oral presentation. International Conference on Mercury as a Global Pollutant- Jeju, Corea (06.2015).

– Salenbien, W., Weide, D. M., Develle, A.-L., Baker, P. A., Fritz S. C., Guédron, S., 2014. The Influence of Sampling Density on Bayesian Age-Depth Models and Paleoclimatic Reconstructions ; Lessons Learned from Lake Titicaca (Bolivia/Peru). American Geophysical Union, San Francisco, USA (12.2014).

– Hellal, J., Guédron, S., Huguet, L., Schaëfer, J., Laperche, V., Joulian, C., Lanceleur, L., Burnol, A., Ghestem, J-P., Garrido, F. and Battaglia-Brunet, F., 2014. Iron and sulphur biogeochemical processes involved in mercury mobility and speciation in an artificial aquifer. 24e Réunion des Sciences de la Terre – Pau, France (10.2014).

– Amouroux, D., Point D., Guédron, S., Acha, D., Lazzaro, X., Chauvaud, L., Bouchet, S., Baya, A., Monperrus, M., Tessier, E., Guyoneaud, R., Goni, M., Thebault, J., Groleau, A., Lorrain, A., Amice, E., Lebec, T., Rocha, S., Heredia, C., Espinosa, M. E., Flores, M., Katari, R., 2014. In situ exploration of processes controlling Hg biogeochemistry in Lake Titicaca hydrosystem (Bolivian Altiplano). 24e Réunion des Sciences de la Terre – Pau, France (10.2014).

– Baya, P. A., Point, D., Guédron S., Lazzaro, X., Espinoza. M. E., Amouroux D. , Chauvaud, L., Amice, E., Thebault J., LeBec T., Acha. D., 2014. Distribution and sources of methylmercury (MeHg) in high altitude lakes ecosystems : The Lake Titicaca case study. 24e Réunion des Sciences de la Terre – Pau, France (10.2014).

– Dutordoir S., Némery J., Arnaud J., Guédron S., Belleudy P., Landas-Maneval J. and , Rivière C., 2013.Particulate flux calculation based on metal contents and suspended sediment concentrations relationship : case study of turbid alpine river (Isère, France). EGU.

– Harris-Hellal J., Huguet L., Guédron S., Schafer J., Joulian C., Burnol A., Garrido F., Laperche V. and Battaglia-Brunet F., 2013. Iron and sulfur biogeochemical processes involved in mercury mobility and speciation in an artificial aquifer, oral presentation. International Conference on Mercury as a Global Pollutant- Edinburgh, UK (07.2013).

– Garcia Bravo A., Bouchet S., Zopfi J., Guédron S., Amouroux D., and Dominik J., Mercury methylation in sediments contaminated by a sewage treatment plant : the role of iron reducing bacteria, oral presentation. International Conference on Mercury as a Global Pollutant- Edinburgh, UK (07.2013).

– Cossa D., Schäfer J., Guédron S., Thomas B., Lanceleur L. and. Chiffoleau J.-F, Methylmercury in the water column at the northwestern Mediterranean margin, oral presentation. International Conference on Mercury as a Global Pollutant- Edinburgh, UK (07.2013).

– Niane, B., Moritz, R., Ngom, P.M., Pfeifer, H.R., Bravo, AGB, Maal, ,I. and Guédron, S. Environmental impact arising from artisanal gold mining and use of Mercury in Eastern Senegal. Poster presentation. 9th Swiss Geoscience Meeting - Zürich, Switzerland (11.11 2011).

– Guédron, S., Huguet, L., Vignati, D.A.L., Liu, B., Gimbert, F., Zonta, R. and Dominik J. Methylmercury production and release from sediments to surface water during tidal cycles in a zone adjacent to salt marshes, Venice lagoon, Italy, oral presentation, International conference on heavy metals in the environment (ICHMET), Gdansk, Poland (19-23.10.2010).

– Liu, B., Yan, H., Li, Q., Wang, C., Guédron, S., Feng, X. and Dominik, J. A puzzle in a Hg contaminated reservoir – Biogeochemical factors of Hg bioaccumulation in the fish of Biahua reservoir, poster presentation, ICHMET 15, Gdansk, Poland (19-23.10.2010).

– Garcia Bravo, A., Chevalley, P.A., Cosio, A., Guédron, S., Ungureanu, V.G., Amouroux, D. and Dominik J. Mercury methylation and trophic transfert in a reservoir contaminated by a chlor-alkaly plant : Babeni reservoir , poster presentation, ICHMET 15, Gdansk, Poland (19-23.10.2010).

– Huguet, L., Gimbert, F., Ferrari, B., Guédron, S., and Dominik J. In situ mercury and methylmercury bioaccumulation kinetic in benthic invertebrates, Venice Lagoon Italy, poster presentation, ICHMET 15, Gdansk, Poland (19-23.10.2010).

– Tołwińska, H., Guédron, S., Liu, B., Szalińska1, E. and Dominik, J. - Mercury in Lower Reach Sediments of the Biala Tarnowska River, poster presentation, ICHMET 15, Gdansk, Poland (19-23.10.2010).

– Harris-Hellal J., Locatelli A., Guédron S., Huguet L., Joulian C., Liu B., Burnol A., Garrido F., Laperche V., and Battaglia-Brunet F., 2010, Iron and sulphur biogeochemical processes involved in arsenic and mercury mobility in aquifers under anoxic conditions, oral presentation, International Society for Microbial Ecology, Seattle, USA (22-27.08. 2010)

– Ariztegui D., Guédron S., Coianiz L., and Piovano E., 2010, Tracking recurring drought/wet intervals and human impact over subtropical South America since the end of the Little Ice Age using Hg content in sediments. AGU conference – The meeting of the Americas, Foz Do Iguassu, Brazil (8-13.08.2010)

– Liu B., Haiyu Y., Guédron S., Feng X., Dominik J., 2010, Mercury biogeochemistry in polluted Baihua Reservoir, China. SETAC conference, Seville, Spain (23-27.05.2010).

– Guédron S., Vignati D. A. and Dominik J., 2009, Partitioning of total mercury and methylmercury between colloids and true solution in overlying and interstitial waters (Lake Geneva). Poster presentation. 7th Swiss Geoscience Meeting, Neuchâtel, Suisse (20 – 21.11.2009). Sumposium1. Water across (scientific) boundaries.

– Guedron S., Grimaldi M., Cossa D., and Charlet L. - Tailing ponds in industrial and small scale gold mines as sources of methylmercury for hydrosystems in French Guiana, oral presentation. International Conference on Mercury as a Global Pollutant- Guiyang, China (7-12.06.2009).

– Polya D., Charlet L., Chounlamany S., Guédron S., Lawson M., Lythgoe P.R., Molton F., Phawadee N. and Spadini L. – Arsenic hazard in shallow groundwaters in Lao PDR (Laos) - Poster - GSA Annual Meeting - Portland, USA (18-21 October 2009).

– Gimbert F., Ferrari B.J.D., Geffard A., Guédron S., and Dominik J. - Kinetics of mercury subcellular fractionation in Chironomus riparius , oral presentation - 14th International Symposium on Toxicity Assessment – Metz, France (29.08-11.09.2009).

– Guédron S., Charlet L., Grimaldi M., and Cossa D.- Dissolved methyl mercury production in gold-mines vs tropical artificial reservoirs (French Guiana), oral presentation. International Conference on Geo-Environmental engineering (7th Japan-Korean-French Seminar) Grenoble, France (22-24.05.2007).

– Guédron S., Grimaldi M., Cossa D., and Charlet L. - Mobilization of dissolved, particulate and methyl mercury in former gold-mined watershed in French Guiana - Oral Presentation, International Conference on Mercury as a Global Pollutant- Madison, USA (6-11.08.2006).

– Guédron S., Grimaldi C., Chauvel C., Spadini L. and Grimaldi M. - Mercury of atmospheric origin in French Guiana soils - Poster presentation - XIIth International Conference on Heavy Metals in the Environnement (Grenoble, 29.05.2004).