title: SEM-EDX analysis in the source apportionment of particulate matter on Hypogymnia physodes lichen transplants around the Cu smelter and former mining town of Karabash, South Urals, Russia.
abstract: Scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX) of particulate matter on lichen transplant thalli (Hypogymnia physodes) was assessed as a complementary technique to wet chemical analysis for source apportionment of airborne contaminants. Transplants (2 month exposure) stationed in the Cu smelter and former mining town of Karabash were compared with those from a control site 30 km south. Particulate matter in Karabash samples (715 analyses) showed higher levels of S, Pb, Cu, Sn and Zn compared with the control (598 analyses). Complex element associations among the particles confounded detailed mineralogical identifications, and therefore a simplified particle classification scheme was devised for source apportionment. Karabash samples contained high levels of particles classified as mining-related (MRP), and these were also identified in control samples, indicating wide spatial dispersion from the smelter and highlighting the sensitivity of the method. It was noted that MRP <2.5-microm diameter were poorly represented on lichen surfaces suggesting this may limit the usefulness of Hypogymnia transplants as proxies when assessing human health impacts from airborne particulates. Analyses of the lichen thallus surface (away from surface particulates) revealed high levels of Cu, Zn, Fe and Pb associated with organics in the Karabash samples compared with the control, with a proportionate loss of K, interpreted as being due to a stress-related increase in cell membrane permeability. This type of analysis may provide a novel SEM-EDX-based method for assessing lichen vitality. The techniques developed are presented and further implications of the study are discussed.
authors.affiliation: Department of Mineralogy, The Natural History Museum, Cromwell Road, London SW7 5BD, UK. bw@nhm.ac.uk
authors.forename: B J
authors.initials: BJ
authors.lastname: Williamson
authors.forename: I
authors.initials: I
authors.lastname: Mikhailova
authors.forename: O W
authors.initials: OW
authors.lastname: Purvis
authors.forename: V
authors.initials: V
authors.lastname: Udachin
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002462:Cell Membrane; D004784:Environmental Monitoring; D008011:Lichens / Q000737:chemistry* / Q000254:growth & development; D019216:Metals, Heavy / Q000032:analysis*; D008855:Microscopy, Electron, Scanning; D000089762:Multidrug Resistance-Associated Protein 2; D010316:Particle Size; D010539:Permeability
chemical_list: C000715087:ABCC2 protein, human; D000393:Air Pollutants; D019216:Metals, Heavy; D000089762:Multidrug Resistance-Associated Protein 2