THE EXAMINATION OF GAMMA-EMITTER CONTAMINATION LEVEL OF THE LICHENS FROM EASTERN AND SOUTH-EASTERN POLAND, COLLECTED IN THE YEARS 1949-1996

The results of investigations of the level of contamination by gamma-r adioactive isotopes of lichens from Parmeliaceae family, collected in the years 1949-1996 are presented. The most important isotope, occurri ng in significant amount was Cs-137. From the natural isotope group al so K-40, Ra-226, Pb-210, Th-234 and Bi-214 were found in few samples. Starting from 1956, the Cs-137 isotope is detected in all collected sa mples with two distinct maxima in 1963 and 1989. Taking into account t he age of the collected lichens, their activity and the level of the r adioactivity fall-out, the full correlation of the obtained results wi th the amount of the radioactive fall-out is observed.