Lichen Biomonitoring as a Tool for Assessing Air Quality in Geothermal Areas

Abstract

To answer the growing concern among inhabitants about possible health and environmental effects due to the industrial exploitation of geothermal resources, lichen biomonitoring programmes have been performed in the Italian geothermal fields of Travale-Radicondoli and Mt. Amiata. In both areas, the mapping of lichen diversity showed that the zone of worst air quality does not extend more than about 500 m from the power plants. Major injury to lichens are probably caused by hydrogen sulphide, a highly toxic gaseous pollutant. In both geothermal fields, the concentrations of trace elements found inside lichen thalli indicated some accumulation of arsenic, boron and sulphur. It is highly likely that hydrogen sulphide is both the main source of atmospheric sulphur and the main pollutant responsible for lichen decline around geothermal installations.