THE BALANCE OF RISK ELEMENTS IN ENVIRONME NTAL SPHERES

The presented study has investigated the balance of major risk element s in environmental spheres. It has to be realized that the above balan ce means solely orientation outline of element cycling which will diff er much in different places and spheres of environment. Our calculatio ns were based on average representation of elements and on average mas s amount entered and released from circulations. The balance is in g o f element ment per year and in percent of loading in relation to the t otal content of element in 20 cm deep top soil. If we start from the a bove prerequisites, referred to arable lands solely, where entering el ements are incorporated into the top soil profile annually, it is evid ent that in top soils the balance of studied elements is balanced. The largest accumulations were observed in Cd (0.81 % of the total conten t and 10.4 g/ha/year) and the lowest ones in Ni (0.015 % and 28 g). No accumulation was found in Co and Cr. Completely different is the situ ation in the soils of forest stands and grasslands where the highest a ccumulation is in the top 2 to 5 cm The accumulation is in this case e xpressed in percentage of the total content higher by 4 to 10 times th an that in the total top soil layer. When we study individual sources of pollution, it is evident that the highest inputs were recorded from atmospheric fall-out which is in Hg 17 times, in Pb 12.4 times, in As 6 times, in Ni 2.2 times, in Cd 1.6 times, in Co and Cu 1.4 times and in Zn 1.2 times higher inputs of elements from application of fertili zers. Loading by fertilizers was 2.1 times higher solely in Cr than th e inputs from atmosphere. Inputs from atmosphere are in Hg 91 %, in Pb and As 82 %, in Cd and Ni 60 %, in Zn and Cu about 53 %, in Co 35 % a nd in Cr 21 %. Total inputs of elements are in Cd 3 times, in Hg, Pb, As, Zn 2 times, in Cu 1.5 times and in Ni 1.2 times higher than their total outputs. Exclusively in Co and Cr outputs were higher than their inputs. Nriagu (1990) reports that anthropic emissions exceed flows f rom natural resources by 28 times in Pb, 6 times in Cu, 3 times in V a nd Zn. Combustion of fossile fuels causes 95 % in V, 80 % in Ni, about 60 % in Hg, Se, Sn of anthropogenic emissions. The resulting balance is presented in Tab. XIV.