evidence: The Maroni River (border between Suriname and French Guyana) is composed by 3 rivers: the Litany, the Lawa and the Maroni). From upstream to the estuary, many gold-mined streams flow into the main rivers and many dredges are present on the rivers themselves. Therefore, the mean Hg concentrations increased from upstream to the estuary: from 128 ± 30 ng g-1 (Litani River), to 169 ± 63 ng g-1 (Lawa River) and 193 ± 53 ng g-1 (Maroni River). (i) The river sector from "upstream to Antécum Pata" is not gold mined on the French side but it is gold mined on the Surinamese side (Oulemali River). Hg concentrations are lower than the Background. (ii) The river sectors of Maripasoula ("Tampok" et "Inini") with the Ouaqui, Grand Inini and Petit Inini rivers are gold mined (235 ± 70 ng g-1).