Garnier J., Martin L. A., Sonke J. E., Souza J., Quintarelli J., Kutter V., Roig H., Bonnet Marie-Paule, Maurice Laurence, Adam E. A. M., Seyler Patrick. (2025). Mercury isotope constraints on artisanal and small-scale gold mining source contributions and redox cycling in the Yanomami Indigenous Territory. Journal of Hazardous Materials, 498, p. 139892 [12 p.]. ISSN 0304-3894.
Titre du document
Mercury isotope constraints on artisanal and small-scale gold mining source contributions and redox cycling in the Yanomami Indigenous Territory
Année de publication
2025
Auteurs
Garnier J., Martin L. A., Sonke J. E., Souza J., Quintarelli J., Kutter V., Roig H., Bonnet Marie-Paule, Maurice Laurence, Adam E. A. M., Seyler Patrick
Source
Journal of Hazardous Materials, 2025,
498, p. 139892 [12 p.] ISSN 0304-3894
Artisanal and small-scale gold mining (ASGM) is a major source of mercury (Hg) contamination in tropical ecosystems, yet tracing Hg sources and transformations remains challenging. This study investigates Hg dynamics in the Yanomami Indigenous Territory (Brazil), a remote and ecologically sensitive region severely affected by illegal ASGM and a recent humanitarian-environmental crisis. We integrate mineralogical, geochemical, and total Hg data with Hg stable isotope analyses (delta 202Hg and Delta 199Hg) from soils, sediments, suspended particulate matter (SPM), and liquid Hg to assess contamination sources and biogeochemical behavior. Hg concentrations reach up to 8470 ng & sdot;g-1 in SPM, with isotopic signatures reflecting both natural and anthropogenic inputs. A binary isotope mixing model based on delta 202Hg reveals variable ASGM-derived contributions. Three distinct groups emerge: (1) a Source Mixing Group showing a continuum between natural and ASGM inputs; (2) a Hotspot Group with high Hg concentrations and isotopic signatures resembling ASGM liquid Hg; and (3) a Redox-Process Group with isotopic deviations indicative of in situ redox-driven transformations under oxic-anoxic gradients. To support interpretation in complex settings, we propose a simplified, semi-quantitative framework integrating source apportionment and environmental processes. This tool enhances environmental forensics and risk assessment in ASGM-impacted areas.
Plan de classement
Sciences du milieu [021]
;
Pollution [038]
;
Géologie et formations superficielles [064]
;
Etudes, transformation, conservation du milieu naturel [082]
Description Géographique
BRESIL ; AMAZONIE ; AMAZONE BASSIN
Localisation
Fonds IRD [F B010095298]
Identifiant IRD
fdi:010095298
