Biomonitoring techniques have been widely used in environmental studies to monitor anthropogenicpollutant. Recently such techniques have been applied also to ascertain the impact of contaminants naturallyreleased by volcanic activity.In the present study a biomonitoring surveys has been performed in many different active volcanic systems:Mt. Etna and Vulcano (Italy), Nisyros (Greece), Nyiragongo (DRC), Masaya (Nicaragua), Gorely (Kamchatka,Russia). We sampled leaves of different species Betulla aethnensis, Pinus nigra, Populus tremula, Senecioaethnensis and Rumex aethnensis on Etna, Cistus creticus and salvifolius on Vulcano and Nisyros, Seneciossp. on Nyiragongo, a Fern on Masaya and Salix arctica at Gorely. All samples were analyzed by ICP-MSand ICP-OES for 49 elements after acid digestion with a microwave oven (HNO3 + H2O2).Major constituents in leaves are K, Ca, Mg, Na, Si, Al and Fe ranging from about 10 3 to 105 ppm.Manganesium, Sr, Rb, Ba, Zn, B, Cu show also relatively high concentrations (100-103 ppm) while theremaining elements (As, Bi, Cd, Ce, Co, Cr, Cs, Ga, Li, Mo, Ni, Pb, Sb, Sc, Se, Th, Tl, U, V, Y and lanthanideseries) display much lower values (10-4-101 ppm). Nearly all investigated elements show their highestconcentrations in the samples collected closest to the main degassing vents (open craters, fumarolic fields).Increased concentrations are also found in the samples collected in the downwind direction where volcanicemissions are prevailingly dispersed.Leaves collected along radial transects from the active vents, highlight that the levels of metals decreasefrom one to two orders of magnitude with increasing distance from the source. The decrease is stronger forvolatile elements, which are highly enriched in volcanic emissions, (As, Bi, Cd, Cs, Pb, Sb, Tl) than for morerefractory elements (Al, Ba, Sc, Si, Sr, Th, U). The different species of plants show significant differences inthe bioaccumulation processes for most of the analyzed elements, in particular lanthanides, which aresystematically enriched in Rumex leaves. Needles of pine (non-deciduous tree) represent a good tool forbiomonitoring investigation because they are important tracers of accumulation with time.The high concentrations of many toxic elements in the leaves allow us to consider some of these plants ashighly tolerant species to the volcanic emissions, and suitable for biomonitoring researches furtherconfirming their strong potential in tracing the impact and geographic distribution of these naturalcontaminants.
|Numero di pagine||1|
|Stato di pubblicazione||Published - 2014|