Epilithic lichen (Xanthoria elegans in Canada, Lecanora muralis in Germany) were gathered from 17 locations in Ontario, Canada (from Lake Ontario to James Bay) and 43 locations in Germany (from the Alps to the North Sea and from the Baltic Sea to the Erzgebirge). Sample aliquots were digested in nitric acid and trace elements were analyzed by inductively coupled plasma-mass spectrometry techniques. The organohalogens were determined
IMPLICATIONSThe results demonstrate that epilithic lichen provide an excellent means to monitor atmospheric deposition over large areas in a fast, simple, cost-effective, and reliable way. This method is fast because lichen specimens can be easily sampled and are abundant in all environmentsprovided that suitable species (i.e., those that are easily determinable and ubiquitous) have been chosen. This method is inexpensive when compared to instrumental methods of measuring atmospheric depositions, which will never be set up in densities comparable to the use of biomonitors. The method is thus very attractive for regions where no high-tech monitoring facilities exist and where large areas will be covered in a short period of time. Finally, the reliability of the method can be shown by comparing the results of this study with those of other types of biomonitoring and direct measurements. This method is expected to extend the spatial resolution and to produce a lichen-based biogeochemical atlas for Germany.as absorbable organic halogens (AOXs) by coulometry. Concentration ranges from Germany for trace element samples and AOXs were determined. The lichen showed high spatial resolution in their element enrichment patterns. This allowed for differentiation between natural and anthropogenic dominance in ambient air concentrations. This biomonitoring method has proven to be very sensitive, fast, and reliable. No clear relationship could be found between trace element and AOX concentrations. The AOX values may reflect individual metabolic rates of the fungal partner in lichen symbionts.