Savaria - A Vas Megyei Múzeumok értesítője 15. (1981) (Szombathely, 1988)

Természettudomány - M. R. D. Seaward: A zuzmók alkalmazása a levegő szennyezettségének indikálására

SAVARIA 15. KÖTET A VAS MEGYEI MÚZEUMOK ÉRTESÍTŐJE 1981 THE USE OF LICHENS TO MONITOR AIR POLLUTION M. R. D. SEAWARD Plants and animals have been used as monitors of environmental conditions for many years. However, any successful use of bioindicators must depend upon the rigorous definition of the scales monitored by the organism and a complete analysis of all the environmental parameters which affect the organism's propagation, establishment and subsequent growth. The use of bioindicators has the obvious advantage of permitting long-term monitoring without widespread establishment and maintenance of costly and sophisticated equipment. Unfortunately most of the bioindication scales which have been developed so far rely on species-diversity counts, or at least on a fairly detailed understanding of the taxonomy of one or more groups of organisms, thereby making the techniques as difficult to employ as sophisticated measuring equipment. Physical and/or chemical surveys do not necessarily measure the air pollutants which are harmful to biological materials; the measuring devices on site and the analytical equipment in the laboratory back-up are restricted for the most part to a limited number of pollutans (usually as part of a national survey) which can be quickly and easily determined. Furthermore, on-site dévides are not evenly spread over the country, often being concentrated in urban and industrial complexes; for example, of the 1300 or so volumetric gagues of the National Survey of Smoke and Sulphur Dioxide in the United Kingdom operating during the period April 1967 to March 1968, only 763 gagues gave sufficient data for the mean daily S0

2 to be calculated, and of these, less than 10)% were located in rural sites. By developing more efficient dispersal mechanisms for gases from pollution sources and by removing particulates, which provided adsorptive surfaces for gases, implementation of clean air policy has in fact resulted in widespread "blanket pollution" ; furthermore the location of industry and power stations away from cities has also added to the atmospheric burden over wide areas. The use of corroborative information derived from bioindication surveys to support the limited data available from rural sites is therefore strongly recommended. An obvious advantage of bioindicators is that these show the results of the action of pollutants on living material - a relevant, if at times rather emotive, approach to determining man's technological impact on the biosphere. It will never be possible to completely replace direct physical and chemical measurements of air pollutant concentrations by the use of bioindicators ; nevertheles, both approaches are necessary for making a detailed or large-scale survey of the distribution of air pollutans, where the extensive use of technical equipment is costly or impractical. Lichens are particularly sensitive to environmental change and are therefore valuable as monitors of pollution. Over the past 14 years extensive use has been made of lichens in surveys to monitor ambient S0

2 levels throughout the world, particularly in Europe (FERRY et al. 1973, HAWKSWORTH and ROSE 1976). Several different 45