Evaluation of trace elements in different species of lichens by neutron activation analysis

Instrumental neutron activation analysis has been applied for the determina tion of trace elements in five epiphytic lichens: Canoparmelia texana, Cano parmelia caroliniana, Parmotrema tinctorum, Parmotrema sancti-angeli and Us nea sp. that were collected at the same sampling area of the Botanic Instit ute, Sao Paulo Brazil. The elemental concentration results showed that thes e five lichens can be chosen in the species intercalibration for biomonitor ing studies. Also, some aspects related to the occurrence, tolerance to pol lution, treatment and ease of sampling of the species are presented.