A CRITICAL-EVALUATION OF THE USE OF NATURALLY GROWING MOSS TO MONITORTHE DEPOSITION OF ATMOSPHERIC METALS

Mosses have been used extensively to monitor atmospheric deposition of heavy metals and other trace constituents. In this paper, evidence fr om multi-element moss surveys is used to discuss the feasibility of th is technique and to critically evaluate factors that may lead to misin terpretation of results. Two aspects receive particular attention: (1) calibration against precipitation data to allow transformation of ele ment concentrations in moss to deposition rates and (2) contribution t o the elemental composition of the moss from sources other than air po llution, such as marine influence, windblown soil dust, and uptake fro m soil via higher plants and subsequent transfer to mosses. Specific p roblems with the use of mosses as biomonitors in the Arctic are also d iscussed.