Determination of trace elements and evaluation of their enrichment factors in Himalayan lichens.

Within the framework of the Ev-K2-CNR research program of the Italian National Research Council a specific task project has been initiated for the identification of trace elements in lichens in remote high altitude areas. This is to evaluate the possibility of using lichens as biomonitors of trace elements of atmospheric pollution. In this preliminary study, more than 20 elements have been determined in some species of lichens collected at different altitudes (from 1300 to 5000 m) in the region of the Sagarmatha National Park (Nepal). Samples of superficial soils were also collected and analyzed to calculate the trace element enrichment factors (EF) using scandium as a normalizing element. Most of the trace elements were determined by instrumental neutron activation analysis (INAA), while lead and cadmium measurements were carried out with electrothermal atomic absorption spectroscopy (ET-AAS). The EF values as well as the elemental concentrations are reported and discussed.