title: Factors to consider for trace element deposition biomonitoring surveys with lichen transplants.
abstract: A trace element deposition biomonitoring experiment with transplants of the fruticose lichen Evernia prunastri was developed, aimed at monitoring the effects of different exposure parameters (exposure orientation and direct rain) and to the elements Ti, V, Cr, Co, Cu, Zn, Rb, Cd, Sb and Pb. Accumulations were observed for most of the elements, confirming the ability of Evernia transplants for atmospheric metal deposition monitoring. The accumulation trends were mainly affected by the exposure orientation and slightly less so by the protection from rain. The zonation of the trace elements inside the thallus was also studied. It was concluded that trace element concentrations were not homogeneous in Evernia, thus imposing some cautions on the sampling approach. A nuclear microprobe analysis of an E. prunastri transplanted thallus in thin cross-sections concluded that the trace elements were mainly concentrated on the cortex of the thallus, except Zn, Ca and K which were also present in the internal layers. The size of the particles deposited or entrapped on the cortex surface averaged 7 microm. A list of key parameters to ensure the comparability of surveys aiming at observing temporal or spatial deposition variation is presented.
authors.affiliation: Laboratoire des Sciences du Climat et de l'Environnement, CEA-CNRS-UVSQ, F-91198 Gif-sur-Yvette, France. sophie.ayrault@lsce.cnrs-gif.fr
authors.forename: Sophie
authors.initials: S
authors.lastname: Ayrault
authors.forename: Roberto
authors.initials: R
authors.lastname: Clochiatti
authors.forename: Francine
authors.initials: F
authors.lastname: Carrot
authors.forename: Laurent
authors.initials: L
authors.lastname: Daudin
authors.forename: James P
authors.initials: JP
authors.lastname: Bennett
mesh_terms: D000393:Air Pollutants / Q000032:analysis; D000397:Air Pollution; D001203:Ascomycota; D004784:Environmental Monitoring / Q000379:methods*; D008011:Lichens / Q000737:chemistry* / Q000378:metabolism*; D013997:Time Factors; D014131:Trace Elements / Q000032:analysis*; D001335:Vehicle Emissions
chemical_list: D000393:Air Pollutants; D014131:Trace Elements; D001335:Vehicle Emissions