Impact of air pollution on mineral composition of Eucalyptus camaldulensis (Dehnhardt) and Ficus retusa (L.) leaves. Egypt.

The impact of different sources of air pollution on mineral composition of the leaves of two common street tree species; i.e. Eucalyptus camaldulensis Dehnhardt and Ficus retusa L. has been investigated. Five air-polluted sites exposed to emissions from iron and steel, cement, limestone, traffic and smelters within Cairo city were chosen in comparison with a control site. Leaf contents of N, P and K were reduced while those of Ca, Na, Fe, Cl and S increased under the impact of air pollution. The effect was more pronounced under the impact of iron and steel and smelters emissions, but was fairly mild under limestone quarry emissions. The contents of the different minerals in leaf surface deposits were significantly above the control at all polluted sites; and the highest concentrations of Fe, Ca and Mg were found under iron and steel emissions, of Na and K under smelters emissions and of Cl and S under traffic emissions. The results were discussed in relation to the observed accumulation of heavy metals in leaf tissues of the two species.

Key words:  air pollution,  Eucalyptus,  Ficus,  minerals