CONTAMINATION OF SOILS IN THE NORTH-BOHEM IAN REGION BY HAZARDOUS ELEMENTS

In the north-Bohemian region with the maximal immissions load in the C zech Republic the degree and extent of soil contamination by hazardous elements has been allocated. The results of investigations are presen ted in the Tabs I to IV and in two maps of soil contamination by As, B e (Fig. 1) and Cd (Fig. 2). Two groups of elements can be distinguishe d: elements indicating mainly soil contamination of immission origin: As, Be, Cd (Pb, Hg, Zn); elements indicating the areal extent of mafic rocks and soil parent materials with their admixture: Co, Cr, Mn, Ni, V (Cu). Excess of the contamination limit has been assessed in an are al form for As, Be and Cd, whereas for Pb, Hg, Zn only locally. The co ntamination limit is meant as excess of the upper limit of the variabi lity of the natural (substrata differentiated) background. This contam ination is extended in the north-east direction of the studied region. The most strongly contaminated districts am the districts. Most and T eplice. The contamination has its origin in the combustion of fossil f uels in power plants, industrial enterprises and in mining activities. The area of soils contaminated by Cd is moved to the north-east. This areas of continuously contaminated soils reflect the trends of isolin es of fly ashes (annual mean of the daily means) 90 to 100 mug.m-3, mo dified by emission sources distribution. Limits of maximal admissible concentrations of hazardous elements in soils have been exceeded only locally for As, Be > Zn, Pb > Cd.