Uranium distribution of a lake sediments in a former mining area

¹ CEMRAD-IRCOM/C2M, 83 rue d'Isle, 87000 Limoges, France
² LSCE, Domaine du CNRS, avenue de la Terrasse, 91198 Gif-sur-Yvette, France

Abstract

During uranium mining activities in Limousin, waters from the mines have been processed and sent back to environment, leading to the deposition of important quantities of radio-elements of uranium series in the sediments of a lake. While the lake was drained, surface and core samples have been collected for analysis using gamma spectrometry. ²³⁸U activities as important as 20 000 Bq/Kg have been measured in surface sediments. The mapping of ²³⁸U in surface sediments and the analysis of ²³⁸U, ²²⁶Ra and ²¹⁰Pb activities in the cores show that the transfer of radio-elements from waters to sediments is mainly due to solid particles carried by the river into the lake.