EFFECT OF COMPOST, BENTONITE AND CaO ON SOME PROPERTIES OF SOIL CONTAMINATED WITH PETROL AND DIESEL OIL

The aim of the study has been to determine the effect of compost, bentonite and calcium oxide on the acidity and selected properties of soil contaminated with petrol and diesel oil. Increasing rates of petrol and diesel oil were tested: 0, 2.5, 5 and 10 cm(3) center dot kg(-1) of soil. The experiment was carried out in four series: without soil amendments, and with compost (3 %), bentonite (2 % relative to the soil mass) and calcium oxide in a dose corresponding to one full hydrolytic acidity. Soil contamination with petrol and diesel oil as well as soil amendments had significant effect on the analyzed physicochemical properties of soil. Soil contamination with petrol caused an increase in pH and base saturation as well as a decrease in hydrolytic acidity, sum of exchangeable base cations and base saturation. The effect of diesel oil on the above soil properties was much weaker than that of petrol, although hydrolytic acidity increased while exchangeable base cations, cation exchange capacity and base saturation decreased under the effect of this pollutant. Among the tested soil amending substances, the strongest and most beneficial influence on the analyzed soil properties was produced by bentonite and calcium oxide, especially in respect of hydrolytic acidity. The effect of compost, although generally positive, was weaker than that of bentonite or calcium oxide.