The study was undertaken to determine the influence of compost, bentonite and calcium oxide on the content of polycyclic aromatic hydrocarbons (PAHs) in soils polluted with petrol and diesel oil, using plants as phytoremediators. Contamination of soil with petrol and diesel oil caused an increase in the total PAHs in soil. The effect of diesel oil on the content of PAHs in soil was stronger than that of petrol in the treatments with spring barley and yellow lupine -maize, in reverse to spring rape -oat. Pollution of soil with petroleum substances led to the increased contribution of naphthalene to the total PAHs at the expense of other hydrocarbons. Bentonite and CaO produced an evidently stronger effect on soil properties than compost, in general causing a decline in the content of PAHs in soil. The phytoremediatory effect of plants was the most beneficial in the treatment with spring rape and oat, but the weakest in trials with yellow lupine and maize. Plants were particularly effective in soil polluted with petrol. Plant Soil Environ. Vol. 59, 2013, No. 7: 287-294
Keywords
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MATERIAL AND METHODS
Methodology of the vegetative trials.A threeyear (2003)(2004)(2005) plant growing experiment was carried out in a greenhouse at the University of Warmia and Mazury in Olsztyn (north-eastern Poland). The trials were performed in polyethylene pots, which were filled with 9.5 kg of soil each. Three types of typical Eutric Cambisols soil, originating from loamy sand and similar in physicochemical properties, were used for the pot trials. The variable factors comprised the type of a petroleum substance: non-lead petrol 95 (Pet) and diesel oil (DO), rates of petrol and diesel oil: 0 and 10 cm 3 /kg of soil, and type of a substance alleviating the negative influence of petrol or diesel oil on soil: compost (3%), bentonite (2%) and calcium oxide in the amount corresponding to 1 hydrolytic acidity (HAC 1 ). In addition, the soil was enriched with aqueous solutions of macro-and micronutrients. Among the three soil amending substances, the compost had a particularly high content of PAHs, including FTH, BaA, CHR, BaP and BghiP. A detailed specification of soils, composition of the three soil amending substances and doses of macro-and micronutrients added to each pot can be found in other paper (Wyszkowska and Wyszkowski 2010). The following plants were tested with respect to the phytoremediation of soil polluted with petrol and diesel oil: spring barley (Hordeum vulgare L.) Polish cv. Ortega, which was grown until the full maturity phase, separating between grain, straw and roots -trial 1, spring rape (Brassica napus var. oleifera) Polish cv. Mazowiecki (main crop) and oat (Avena sativa L.) Polish cv. Borowik (aftercrop) -trial 2, and yellow lupine (Lupinus luteus L.) Polish cv. Parys (main crop) and maize (Zea mays L.) Polish cv. Scandia (aftercrop) -trial 3. Spring barley, oat, yellow lupine and maize were grown for green matter. Throughout the whole study, constant soil moisture at the level of 60% of water capi...