Fig. 2: Concentrations of mercury in depositing materials and surficial soil in Madre de Dios, Peru.

A Map of the five sampling sites shown as yellow circles. Two sites (Boca Manu, Chilive) are located in areas remote from artisanal gold mining, and three sites (Los Amigos, Boca Colorado, and Laberinto) are located in mining-impacted areas, with mining towns shown as blue triangles. The insets show a typical forested remote site and deforested mining-impacted site. In all figures, the dashed line represents the demarcation between the two remote sites (on the left) and the three mining-impacted sites (on the right). B Gaseous elemental mercury (GEM) concentrations at each site for the 2018 dry (n = 1 independent sample for each site; square symbol) and wet (n = 2 independent samples; square symbol) seasons. C Concentration of total mercury in precipitation collected in forested (green boxplots) and deforested (brown boxplots) areas during the 2018 dry season. For all boxplots, the line represents the median value, the box shows Q1 and Q3, and the whiskers denote 1.5 times the interquartile range (n = 5 independent samples for each forested site, n = 4 independent samples for each deforested site). D Concentration of total mercury in leaves collected during the 2018 dry season from the canopy of Ficus insipida and Inga feuillei (left axis; dark green square and light green triangle symbols, respectively) and as bulk litter on the ground (right axis; olive green circle symbol). Values are shown as mean and standard deviation (n = 3 independent samples for live leaves for each site, n = 1 independent sample for litter). E Concentration of total mercury in surficial soils (top 0–5 cm) collected during the 2018 dry season (n = 3 independent samples for each site) in forested (green boxplots) and deforested (brown boxplots) areas. Data for other seasons are shown in Figs. S1 and S2.