DETERMINATION AND SPECIATION OF MINOR AND TRACE-ELEMENTS IN VOLCANIC EXHALATIONS BY NAA

Volcanic gases in the temperature range from 269 degrees to 635 degrees were sampled by means of a filter combination, consisting of two activated charcoal filters, a cooler and a condensate trap. Samples of the steam plume were taken additionally to quantify the depletion of the elements after condensation and dilution by the atmosphere. The elements F, Cl, Br, I, As, Sb, Se, Te and Hg were determined by instrumental and radiochemical NAA. The data obtained are compared to literature values and the total amount released is estimated. The concentrations in the condensate are compared to the amounts on the filters, enabling the identification of some of the compounds present in the gases. Objects of the investigation were Stromboli and Vulcano in Southern Italy.