Figure 2

Boxplot of mercury sediment contents for the whole of French Guiana, the five main rivers studied and gold - mined and non - gold - mined streams (GMS and NGMS). Two aberrant points measured along the Approuague River were removed from the analysis (values of 10.05 and 11.2 μg g^-1, respectively). Statistical differences between groups according to a Kruskal-Wallis test are indicated by the letters above the boxplots as well as the number or samples (n).