VARIATION IN THE CHEMICAL-COMPOSITION OF RAINWATER FROM THE TUSCAN APPENNINES (VALLOMBROSA AREA)

The Vallombrosa area, in the Tuscan Appennines, is heavily affected by acid deposition. The phenomenon has shown an increasing trend in the present decade. Calcareous material from far off, occasionally transported by wind, can influence the chemical composition of rainwater. Wet, dry and stem-flow samples, collected in the same area, show a strong presence of free acidity and considerable concentrations of heavy metals, mainly lead and cadmium. Canopy leaching effects are observed in rainwater collected under the crown of deciduous tree.