Abstract
The effect of wet ashing, dry ashing and microwave procedure for the determination of heavy metal (Pb, Cd, Fe, Cu, Mn and Zn) levels was investigated in Lichen samples by GFAAS. The study of sample preparation procedures showed that the microwave method was the best. The recovery of heavy metals was very good and precision and accuracy were compatible with standard reference materials. Palladium and aluminum sulfate were used as a modifier.