The assessment of lichens as bioindicator of heavy metal pollution from motor vehicles activites

The contamination of heavy metals released by traffic activities on roadside soils and crops are important problems in developed and developing countries for decades. An assessment of the extent of pollution in roadside soils is a key procedure to protect their ecological function and sustainable agriculture. The objectives of this study were to determine heavy metal contamination of roadside soils that originated from motor vehicles through the use of eight different lichens species situated along D-950 motorway in Erzurum. The results showed that the contamination of Pb, Cr, Cu, Cd, and Ni in roadside soils stemmed mainly from traffic activities, especially for Pb and Cd in this study area judging by their distribution patterns and their enrichment factors. Some of the lichen species such as Xanthoria candelaria (L.) Th. Fr., Lecanora muralis (Schreb.) Rabenh. and Xanthoria elegans (Link) Th. Fr., present in the region can be used to monitor pollution of traffic origin and X. candelaria, in particular, is a very good indicator of pollution of traffic origin. This kind of lichen could be an easy and cost-effective means of air pollution monitoring.