Natural Environment Monitoring 2007, No 8, 51-56
ACCUMULATION OF HEAVY METALS AND MORPHOLOGICAL CHANGES IN THALLI OF HYPOGYMNIA PHYSODES (L.) NYL. LICHEN
Małgorzata Anna Jóźwiak
Summary
Specific response of organisms to changes in environment is named biomonitoring, and organisms sensitive to these changes are called bioindicators. Thanks to regular tracking of biotests, chemical and macroscopic analyses, data on qualitative changes of ecological systems are obtained. Characteristic constitution and physiology of lichens qualify these organisms to be used in biomonitoring research. The most important lichen features, which are of primary importance, are as follows: ability to absorb pollution on the whole external structure of thallus due to lack of surface protective layer, moisture uptake from the atmosphere together with pollutants deposited on dust particles, year-round continuous vegetation and environmental eurytopicity. Research on environmental pollution by heavy metals in Kielce was carried out in 2006. Grafting of Hypogymnia physodes (L) Nyl. lichen thallia was done in quarterly cycles in selected stands in the city. Grafted lichen thallia were taken from standard clean regions of Northeast Poland (Borecka Forest), and then placed on tree trunks close to research stands. Chemical analysis of heavy metals (Cu, Pb, Fe, Cd, Zn) was performed in “0” sample before exposure, and then another one after 3-month impact of biotopic factors. During macroscopic research, thallus structure was examined using stereoscopic microscope and type of occurring changes (dye penetration, thallus shape, damages of structure on thallus surface) were determined. Results and their evaluation showed that average concentration of tested metals in 2006 in Kielce amounted to 58,87 mg•kg-1 d.w., and reached the highest average values in IV quarter (61,30 mg•kg-1d.w). From all tested metals the highest concentration was noticed for iron (annual average of 153,81 mg•kg-1 d.w.) and for lead (annual average of 52,82 mg•kg-1 d.w.), while the lowest concentration was detected for cadmium (Cd) – fig. 8. Morphological changes of Hypogymnia physodes thallus structure are displayed as colour changes (whitening, browning, blacking) – photo. 3, and severe damage of morphological structure that is characteristic for systematic features of this species (radial greengray rosettes) into spalling, necrotic, brittle and curled thallia come off substratum (photo. 1, 4).
