[Pollution in Lake Leman. Evidence for the accumulation of tin in crustacean plankton: first results obtained by X ray spectrography].

Zooplankton was collected monthly from Leman Lake, from November 1976 to April 1977. Six of the most representative species of freshwater zooplankton were analyzed: Bosmina sp, Daphnia longispina, Bythotrephes longimanus, Leptodora kindtii, Eudiaptomus gracilis and Cyclops prealpinus. All of the samples were shown to accumulate tin in their different organs and tissues where high values were generally found. The consequences of concentration of this toxic element for aquatic food chains are discussed.