The use of corticolous lichen species to assess the level of air pollution with heavy metals

Abstract

The paper presents the preliminary results obtained in a study aimed to assess the level of air pollution with heavy metals in urban areas by means of using bioindicators. The tests were carried out in one of the most polluted cities in western Romania, using as bio-indicators corticolous lichens collected from seven representative sites for air quality in the city. The assessment level of air pollution with heavy metals (Cd, Ni, Pb, Cu, Mn, Zn, Cr) was based on the effect that their presence could induce on lichens. Thus, two methods were used for the quantification of the effect such as: a) IAP method, variation in diversity and abundance - calculation of the value of Index of Atmospheric Purity, IAP and b) determining the content of heavy metals in the lichen thalli, respectively. Classification of air quality from the seven sampling sites in pollution classes (low pollution, moderate pollution, high pollution and very high pollution) was based on the statistical tests for correlation between the metal concentration in the air and the specific parameters for the two evaluation methods (the IAP index value for the first method and the metals concentration in the lichen thalli for the second method). The tests results revealed a differentiated air quality in the seven sites, also indicating the method of biomonitoring with corticolous lichens as a viable option for assessing the air quality in polluted areas with heavy metals.