DISTRIBUTION OF SULPHUR AND HEAVY METALS IN FOREST FLOOR HUMUS OF THE CZECH REPUBLIC

Forest humus, which has a large cation binding capacity (up to 550 meq/100 g), and provides relatively very stable bindings with elements and their compounds, can effectively adsorb elements from atmospheric deposition and retain them overa long period. In order to test the monitoring potential of usingforest humus to retain the recent and long-term accumulated loadsof 14 elements (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mo, Ni, Pb, S, V,and Zn), samples of coniferous forest floor humus (H or Oh horizon) were collected over an area of 78 864 km2 using a 20 × 20 km scale grid of sampling points overlaid on theentire territory of the Czech Republic (CZ). Data from 192 pointsand the distribution of the concentrations of individual elementsin forest floor humus are presented here. The extent of relatively very high loading covers 18% of CZ and includes thefollowing four hot spots: an area in the western part of centralBohemia, northwestern Bohemia in the lignite coal mining area, the cross-border area in the Sudeten mountains in northern Bohemia, and the black coal mining area and industrial centre innorthern Moravia. Relatively high, moderate and low loads of theelements were observed in 42, 30, and 28%, respectively, of CZ.Coniferous forest floor humus is evenly spread in the Central European territory and has proved to be a suitable and sensitiveindicator of long-term relative atmospheric deposition loads.