Lichens as biomonitors of heavy-metal pollution

The ability of lichens to accumulate different air pollutants beyond their needs in line with the atmospheric levels, has conducted to their widely acceptance as biomonitors of inorganic and organic air pollution. Either by determining the concentration of accumulated pollutants or tracking for damages in their health promoted by pollutants, lichens are used for environmental assessment worldwide. In this chapter we review the state-of-the-art on the use of lichens as biomonitors of heavy metal pollution considering new findings and applications in recent years. In order to aim on the acquiring of reliable results in inorganic air pollution using lichens, we critically review different alternatives of sample collection and treatment, analytical determination and data analysis for carrying out biomonitoring studies. In this context the main features of lichens as metal bioaccumulators and the related analytical problems in their use are debated.