SPATIAL DISTRIBUTION OF VARIOUS FORMS OF IRON IN HEAVY METAL POLLUTED SOILS

The paper aimed to determine the content of total and soluble iron forms in the top soil horizon (0-10 cm) and present their spatial diversification in the area of zinc and lead ores presence in the vicinity of ZGH "Boleslaw" Mining and Metallurgical Plant in Bukowno near Olkusz. In 139 soil samples total iron content was determined after sample digesting in concentrated mineral acids (HNO3 + HClO4) and soluble forms were extracted with 1 mol . dm(-3) HCl and with 1 mol . dm(-3) NH4NO3 solutions. Fe content in the obtained extracts was assessed by means of atomic absorption spectrometer with flame atomizer. A considerable accumulation of iron, seriously exceeding the amounts most frequently noted in the soils of Poland was determined in the analyzed samples. Extractant solutions used for iron dissolving in the investigated soils were characterized by different abilities to release this element. Diluted hydrochloric acid dissolved on average 21.5 % and ammonium nitrate solution on average only below 0.1 % iron in soil. The highest contents of iron soluble in diluted hydrochloric acid were assessed in the areas with the highest total content of this metal to the north and north-west of ZGH "Boleslaw" and in the vicinity of post-flotation wastes settlement tanks. On the other hand, the greatest quantities of iron released with ammonium nitrate solution were found in the vicinity of Pomorzany Mine and on the most acidified soils of the analyzed area.