ATMOSPHERIC MERCURY EMISSION AT SOLFATARA VOLCANO (POZZUOLI, PHLEGRAEAN FIELDS, ITALY)

Mercury concentrations in air and in condensed steam coming from fumarolic activity at the Solfatara crater (Phlegraean Fields - Italy) were determined. In the condensed steam, mercury was found mainly associated as Hg-S complexes and showed a flux in the range from 0.9 to 4.5 g day(-1). Using the point monitor technique, high values (up to 690 ng m(-3)) of atmospheric mercury levels were observed only close to the main exhaling areas, while background levels (2 ng m(-3)) were measured over the crater area using the lidar technique. An upper limit (<2.4 g day(-1)) for the flux of elemental mercury in air was estimated with the lidar. This remote sensing technique also allowed to assess an upper limit for the SO2 flux (<24 kg day (-1)).