Lichens and mosses are cryptogamic organisms with a number of features in common. They lack root systems, have a high cation-exchange capacity (CEC), and depend largely on atmospheric deposition for their nutrient supply. Mosses and lichens therefore have elemental compositions reflecting in an integrated way gaseous, dissolved and particulate elements in atmospheric deposition. Lichens and mosses ... are the principal component of terrestrial flora in many ecosystems of continental Antarctica and can play a very important role as bio-monitors of persistent contaminant deposition around scientific stations and in field camps.
Owing to their slow growth rates and long life cycles (probably of up to some 100 years), lichens behave as long-term integrators of persistent atmospheric pollutants; the analysis of 50- to 60-year-old specimens may yield information about DDT and other POP deposition. As a rule, concentration of local and long-range transported contaminants in lichen thalli is much higher than that in the atmosphere or snow, and this makes analytical determinations easier. The average content of HCB, HCH, DDTs and PCBs in lichens and mosses collected in 1985 and 1988 in the Antarctic Peninsula and northern Victoria Land ranged from 0.2–9.9 ng g–1 dry wt.