Garnier J. auteur aut IRD Martin L. A. auteur aut IRD Sonke J. E. auteur aut IRD Souza J. auteur aut IRD Quintarelli J. auteur aut IRD Kutter V. auteur aut IRD Roig H. auteur aut IRD Bonnet Marie-Paule auteur aut IRD Maurice Laurence auteur aut IRD Adam E. A. M. auteur aut IRD Seyler Patrick auteur aut IRD text journalArticle eng text/pdf born digital access 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. specialized Source apportionment Redox cycling Gold-mining Amazon Basin BRESIL AMAZONIE AMAZONE BASSIN 021 064 038 082 498 139892 [12 p.] 2025 0304-3894 https://www.documentation.ird.fr/hor/fdi:010095298 10.1016/j.jhazmat.2025.139892 0304-3894 [F B010095298] https://www.documentation.ird.fr/hor/fdi:010095298 https://www.documentation.ird.fr/intranet/publi/2025-11/010095298.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2025-11-18 2025-11-18 fdi:010095298 fre