Determination of Toxic Heavy Metals in four Different Lichen Species of Tamil Nadu, India

Biomonitoring studies provide valuable information about the quantity and quality of pollutants in the atmosphere and can be very effective as an early warning system to detect environmental changes. The present study was undertaken to determine the heavy metal concentration in lichens from Velachery, Tiruvallur (Chennai) and Chithanji, Kalathur (Vellore) in Tamil Nadu, India. Physcia lichen was collected from Velachery and Porina interestes lichen was collected from Tiruvallur, the pollution rich zones. Buellia disciformis lichen was collected from Chithanji and Lecanora allphona lichen was collected from Kalathur, the unpolluted zones. The residue was used for the analysis of heavy metals like Lead, Chromium, Zinc, Copper, Nickel and Iron using atomic absorption spectrophotometer (AAS). The results obtained showed the lichens in the respective places have absorbed the heavy metal which is most prone in the area. From the present study it is inferred that the heavy metal levels in lichens with the atmospheric deposition reflects the toxic level of heavy metals in our environment and gives evidence of air contamination at industrial and market areas with heavy traffic.