STRATEGIES IN SAMPLING AND SAMPLE HANDLING IN THE CONTEXT OF LARGE-SCALE PLANT BIOMONITORING SURVEYS OF TRACE-ELEMENT AIR-POLLUTION

Aspects of sampling and sample handling in the context of large-scale plant biomonitoring surveys of trace element air pollution are address ed. Topics such as survey goals and planning, choice of elements, biom onitor species (lichens, mosses, bark), interspecies calibration, SO2 effects, local variation, comparability of results, sample homogeneity , the problem of soil-derived elements, and elemental analysis are dis cussed. The paper stresses the need for stringent accuracy control, in dicates the importance of local variation in the concept of the survey , and underlines the relevance of multi-elemental analysis. Furthermor e, factor analysis is indicated as a powerful mathematical tool in dea ling with the presence of both soil particle contamination and soil-de rived absorbed elements.