Comparative study of the suitability of three lichen species to trace-element air monitoring

To investigate the suitability of three lichen species (Cetraria islandica Evernia prumastri, and Ramalina farinacea) as transplants to trace-element air biomonitoring, they were exposed on substratum-free supports, from July 1996 until July 1997, in three European Countries with different elimates (Germany, Italy, Romania), at six sites with different tapes of air pollutants (two in each country). After 2, 4, 6 and 12 months of exposure, some portions of thallus were collected, prepared, and measured by instrumental neutron activation analysis (INAA) at the Institute of Physics and Nuclear Engineering in Bucharest and by energy dispersive X-ray fluorescence analysis (EDXRFA) at the University of Hohenheim in Stuttgart. Fifteen environmentally relevant elements: As, Br, Ca, Co, Cr, Cu, Fe, K, Mn, Ni, Ph, S, Sb, V, and Zn were determined. The analytical results ere compared statistically. To study the distribution of the trace-elements between the lichens and the lichen throughfall beater inside a virtual column, the throughfall water was collected under the lichen transplants during 6 and 12 months. The dried residues were analysed by INAA at Bucharest. The accumulating capacity for all investigated species is evident. For a comparative evaluation, the initial element contents. the "accumulation factors" relative to the bulk (deposition. the interspecies "calibration factors", and the "retention efficiencies". defined of ratios of the lichen enrichment to the sum of this enrichment and the content in the lichen throughfall beater, ere considered, These criteria attest the best suitability for Evernia prumastri. Followed by Ramalina farinacea and Cetraria islandica. (C) 2002 Elsevier Science Ltd. All rights reserved.