Explosive eruptions and volcanic passive degassing inject large quantities of gas and particles into theatmosphere that are ultimately deposited at the Earth’s surface through wet or dry depositionprocesses, affecting the atmosphere, the hydrosphere and the biosphere. Mount Etna (Italy) is one ofthe most prodigious and persistent sources of gases and particles to the troposphere. Volcanicemissions were studied at Etna volcano by using moss-bags technique. Mosses (Sphagnum species)were exposed around the volcano at different distances from the active vents to evaluate the impact ofits emissions into the atmosphere and in the local surrounding. The results confirmed the huge amountof silicates, sulfates and halides compounds emitted into the atmosphere from Mount Etna. X-raymicroanalysis showed that chemical composition of the particles is mostly defined by silicate (frompure silica to metal-rich silicate composition) and sulfate/halide compounds. The contents of majorand trace elements in the Sphagnum moss-bags significantly increased after their exposure tovolcanic emissions, confirming mosses as efficient accumulators. Metals uptake rate rapidlydecreases with the distance from the volcanic emission vents. The elements that showed the greatestaccumulation after exposition were S, Na, Fe, Al, Cu, V, As, Cd, Li, Se, Sc, Th, Bi and Tl. This studyconfirmed the marked environmental impact of volcanic emissions in the eastern sector of Etna,leading to an intense “geochemical anomaly” of volatile major and trace elements due to thefumigation by the volcanic plume, in agreement with passive biomonitoring studies reported byprevious authors. Finally, moss-bags techniques provide a cheap and efficient method to investigatequantitatively in space and time the environmental impact of volcanogenic atmospheric deposition.
|Numero di pagine||6|
|Stato di pubblicazione||Published - 2014|