Lichen monitoring as a potential tool in environmental forensics: Case study of the Cu smelter and former mining town of Karabash, Russia

The aim of this paper is to showcase the use of lichens in environmental forensics from an assessment of atmospheric deposition in and around the Cu smelter and former mining town of Karabash, Ural Mountains of Russia. Hypogymnia physodes was collected on its bark substrate in July 2001 from a 'reference' site (c. 25 km SWof Karabash) and transplanted to 10 stations along an approximately 60 km SSW-NNE transect centred on Karabash. Transplants were collected after 2 and 3 month exposure periods. The elemental compositions of Hypogymnia and potential sources of particulates in the study area (smelter blast furnace and converter dusts, wastes, tailings, road dusts, metallurgical slags and top soils) were determined by inductively coupled plasma optical emission spectrometry (ICP-OES) and quadrupole ICP mass spectrometry (ICP-MS), and the Pb isotope compositions of the lichens and smelter dusts by multicollector ICP-MS. Particulates on lichen surfaces were analysed by scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX). The method of lichen transplantation, combined with multi-element and surface particle elemental analysis, high-precision Pb isotope ratio determinations and modelling, was shown to be useful for the tracing of the smelter signal, and components from different smelter processes, for more than 25 km from Karabash town. The lichen monitoring methodology is discrete and comparatively low cost, enabling atmospheric deposition from natural and anthropogenic sources to be determined over short (>3 month) periods, and is therefore a valuable qualitative tool for environmental forensics.