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Biol Trace Elem Res (2012) 148:396408 DOI 10.1007/s12011-012-9378-9
A Study of Air Pollution with Heavy Metals in Athens City and Attica Basin Using Evergreen Trees as Biological Indicators
Thomas Sawidis & Panagiotis Krystallidis &
Dimitrios Veros & Mukesh Chettri
Received: 30 November 2011 /Accepted: 26 February 2012 /Published online: 14 March 2012 # Springer Science+Business Media, LLC 2012
Abstract Concentrations of five metals (cadmium, chromium, copper, nickel and lead) were determined in tree leaves collected from 13 areas of the Attica basin and Athens city, Greece. Geographical distribution patterns were investigated, and factors affecting toxic element accumulation in trees were discussed. The mean heavy metal content in the tree leaves is described in the descending order of copper>lead>nickel> chromium>cadmium. Generally, the most damaged areas have been proved to be those near the city center and in the vicinity of the Attica highway. The geomorphological relief of the area plays an important role in the dispersion of airborne particles from pollution sources to the surrounding area. Areas on the NE region are also polluted mainly due to wind directions. In Citrus aurantium leaves, with relatively impermeable cuticle, high chromium, copper and nickel concentration would be possibly caused only by significant stomatal uptake. The conifer tree Pinus brutia providing a rough leaf surface also showed elevated concentrations, especially of cadmium and lead. The thick waxy cuticle of the sclerophyllous broad-leaved Olea europaea forms a smooth sheet increasing the barrier properties of the leaf epidermis and causing a reduction in leaf permeability. The dense trichomes of the abaxial epidermis of Olea europaea also act as a pollution screen keeping away the air particles from the epidermis stomata. The presence of a certain metal within the leaf cells could reduce the uptake or toxicity of some others.
Keywords Athens . Attica . Heavy metals . Air pollution . Trees
Introduction
Atmospheric pollution constitutes one of the major problems in urban areas. The greater Athens area has been facing increased air quality problems during the last three decades, due to population shift, increased industrialization, continuously increasing traffic and due to its geographical relief [1]. Transport is a major source of air pollution in cities, and therefore, special attention is given to traffic pollutants, such as heavy metals. Very intense road...