ACIDITY AND SORPTION PROPERTIES OF ZINC-CONTAMINATED SOIL FOLLOWING THE APPLICATION OF NEUTRALISING SUBSTANCES

Soil plays the most important role in the cycling of elements in the terrestrial environment. Contamination of soil with heavy metals have effect on all soil organism and plants. For this reason, studies have been carried out to assess the possibility of neutralising the effect of zinc (0, 150, 300, 600 and 1200 mg Zn.kg(-1) of soil) on soil properties by applying neutralising substances (compost, bentonite and zeolite). Soil acidity and sorption properties depended on zinc contamination and on the type of neutralising substances added. In the series without an addition of neutralising substances, increasing zinc soil contamination resulted in a decrease in total exchangeable bases, in cation exchange capacity and in the saturation degree of the degree of base saturation, and an increase in soil hydrolytic acidity. An addition of bentonite to zinc-contaminated soil had the most advantageous effect of all the additions of neutralising substances on the tested soil properties. It resulted in an increase in soil pH, in total exchangeable bases, in cation exchange capacity, in the degree of base saturation and simultaneously decreased soil hydrolytic acidity compared to the series without additions. Adding zeolite and compost to soil had a small and usually insignificant effect on soil acidity and soil sorption properties.