A study on capture and deposit of air-borne heavy metal elements with suburban forests

Abstract

Behaviors of heavy metal elements with air-borne dusts carried into suburban forests were investigated. Concentrations of Cr, Pb, Ni, Fe, Cu, Mn, and Zn held in rain water, in through-fall and in run-off water were measured for 8 months from May to December 1984. The through-fall were collected from 8 different vegetations which stood close to each other on a hill adjacent to the city of Okayama Japan. Besides the concentrations of the elements in the forests soils and in the forest trees were measured. The concentrations of the elements in the throug-hfalls were not always higher than those in the rain water, that suggested the captures of the heavy metal elements by the canopies weren't so simple as to have been presumed. On the other hand, the run-off water was reduced remarkably in the concentration compared with the through-fall. The filtration and defoliation caused heavy metal elements to accumulate in Ao-layer to a great extent. Forest treees made also the suburban forest work as an effective heavy metal elements filter by deposits of the elements within tree bodies.