A study of metal distribution from lignite fuels using trees as biological monitors.

Concentrations of five metals (Cd, Cu, Mn, Fe, Zn) were determined in tree leaves collected from an area with large coal-fired plants in Ptolemais, Macedonia, Greece. The analyses were carried out with flame atomic absorption spectroscopy. Mean heavy metal content in the tree leaves is, in descending order, Fe>Mn>Zn>Cu>Cd. In Populus nigra and Salix babylonica the dense piled leaves and the widespread root system are the reasons for high heavy metal uptake. Conifer trees Pinus nigra and Juniperus arizona, which have a rough leaf surface, also had elevated concentrations. Leaves with a smooth surface were less contaminated. The presence of one metal within leaf cells may reduce the uptake or toxicity of other metals. Fruits accumulated less heavy metal than the corresponding leaves. The most damaged areas are those in the direct vicinity of the coal power plants, and the rate of damage caused in the environment is affected by the main wind direction. All sampling sites in Ptolemais basin are generally more or less polluted when compared with the control site.