J. Phys. IV France
Volume 107, May 2003
Page(s) 863 - 865

J. Phys. IV France
107 (2003) 863
DOI: 10.1051/jp4:20030434

The large impact of gold-mining in total-Hg content in sediment of the dam lake of Petit Saut (French Guiana)

M.-A. Bélières1, M. Pourchet1, L. Spadini2 and L. Chalet2

1  Laboratoire de Glaciologie et Géophysique de l'Environnement, CNRS, Université J. Fourier, BP. 96, 38402 Saint-Martin-d'Hères, France
2  Laboratoire de Géophysique Interne et Tectonophysique, Maison des Géosciences, 1381 rue de la Piscine, Domaine Universitaire, 38041 Satin-Martin-d'Hères, France

Gold-mining is a major source of Hg pollution, especially in the tropical rain forest of South America. This pollution has been shown to strongly increase the local natural background. Does this pollution ex tend far beyond the local areas? Here we present results concerning sediments cored in the large dam lake of Petit-Saut in French Guiana. This dam lake, created in 1994, collects waters from a large catchment area where gold-mining activity has been developing since the last century. and still is. Sediment depth profiles in 210Pb and in total-Hg revealed a high Hg content in the last 4 years. This can only result from anthropogenic activities, which could be due either to propagation of sediments from gold mining sites, or chemical processes acting in recently flooded soils (both processes being related to the dam creation).

© EDP Sciences 2003