Large scale screening of spatial heavy metal distribution on territory of Bulgaria using Populus nigra as monitor. Final report for the period 15 December 1994 - 14 December 1996

摘要

Large scale screening of heavy and toxic metals in Bulgaria using Populus nigra (poplar) leaves as biomonitor was done. Samples collected on more than 130 sites, were analyzed by neutron activation analysis and atomic absorption spectrometry. Elements As, Au, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Cu, Eu, Fe, Hg, K, La, Mn, Na, Ni, Pb, Rb, Sb, Sc, Sm, Sr, Th, and Zn were determined. On average, mean values obtained for most of elements, were comparable to the literature ones for terrestrial plants and similar to comparable studies in Europe. Within the area investigated, the highest concentrations were found near metallurgical facilities around Sofia, and some ''hot spots'' which increased values for several elements at some other locations. Cluster analysis on limited number of elements yielded four regions with different levels of pollution: (1) Sofia and Plovdiv areas (the most polluted); (2) southwestern Bulgaria, middle-northern Bulgaria, Varna and Stara Zagora areas; (3) middle Bulgaria and the Bourgass region; and (4) northeastern Bulgaria (the least polluted). Study done on poplar leaves from unpolluted area during a course of 7 years showed fairly constant content of elements during this period, thus providing appropriateness of poplar leaves as a biomonitor. (author). 8 refs, 2 figs. (Atomindex citation 28:029282)