Evaluation of the environmental impact of volcanic emissions from the chemistry of rainwater: Mount Etna area (Sicily)

The S, halogen and NO3 contents of rainwater samples from the Etnean area were studied in order to define the environmental impact of plume emissions on the local environment. Samples, collected on a network of 11 bulk rain gauges, show significant variability in anion content, which can be ascribed to different meteorological and environmental conditions at each sampling site and to a variable distance from the different source areas. Data analysis suggests that S, F, Cl and Br are mainly magma-derived, whereas NO3 mainly originates from anthropogenic sources. Samples collected from sites close to craters display considerable temporal variability, with increased anion concentrations being recorded during periods of intense plume degassing. Variations in precipitation also induce significant modifications in the chemistry of the meteoric-derived Etnean groundwaters.