Critical remarks on the use of terrestrial moss (Hylocomium splendens and Pleurozium schreberi) for monitoring of airborne pollution

Duplicate samples of the two terrestrial moss species Hylocomium splendens and Pleurozium schreberi, which are widely used to monitor airborne heavy m etal pollution, have been collected from eight catchments spread over a 1,5 00,000 km(2) area in northern Europe. These were analysed for a total of 38 elements by inductively coupled plasma-mass spectrometry, inductively coup led plasma-atomic emission spectrometry and cold vapour-atomic absorption s pectrometry techniques. Results show that the moss species can be combined without interspecies calibration for regional mapping purposes. For the maj ority of elements the observed within-catchment variation is large - big co mposite samples over a large area should thus be collected when moss is to be used for monitoring purposes. For the majority of elements the input of dust governs moss chemistry. For a reliable 'contamination' signal over a s izeable area a major source is needed. Some elements show a dependence on c limate/vegetation zone. In coastal areas the input of marine aerosols will alter the chemical signal obtained from moss samples. (C) 2001 Elsevier Sci ence Ltd. All rights reserved.