PAHs (polycyclic aromatic hydrocarbons) are widespread in the natural environment. They are suspected to have mutagenic, carcinogenic and teratogenic effect on our organisms. Production of wholesome and high quality vegetables does not necessarily involve selection of adequate farmlands or substrates used for vegetable growing. Combustion processes are a source of PAHs in the soil and air. Excessive levels of PAHs are accumulated when the balance between their decomposition in soil and supply from other sources is disrupted. The objective of the present research has been to evaluate the effect of anthracene and pyrene on the concentration of selected trace elements in butter lettuce (Lactuca sativa L.), cultivar Vilmorin, grown on substrates with different nutrient abundance. A pot experiment in four replications was carried out twice in the spring of 2007 and 2008. The pots were maintained in a greenhouse at the University of Warmia and Mazury in Olsztyn. Lettuce was grown under the minimum (optimum) and triple (II fertilization level) substrate abundance in nutrients. In the second variant o the experiment, when the nutrient abundance was elevated, nitrogen was split into two doses: 2/3 of the whole rate were added before planting lettuce seedlings, and 1/3 of the rate was introduced 10 days afterwards. In the first variant, when the nutrient abundance was minimal, all of the nitrogen was added in a single dose. Spraying the lettuce plants with anthracene (ANT), pyrene (PYR0 or their mixture started 10 days after planting. Foliar introduction of the tested PAHs continued for 25 days (in the amount of 1.8 cm3 day–1 at a concentration of 100 mg dm–3) until the vegetative season finished. At the same time, an identical total amount of the PAHs was added to soil as aqueous solution, at 7-day intervals, according to the same pattern. Determinations of the concentrations of heavy metals (Cd, Cu, Ni, Cr, Zn, Mn) was performed with the ASA method, having first mineralised (HClO4+HCl+HNO3) the plant material which had been dried at 60oC. The determinations were compared with certified material (CTA-VTL-2). Concentrations of the trace elements in butter lettuce were significantly varied depending on the experimental factors. A more abundant substrate significantly raised the levels of Cd, Zn and Mn, but had no effect on concentrations of Cu, Ni and Cr. The way the PAHs were applied did not have any influence on modifications in the determined levels of the metals. Out of the two analysed PAHs, anthracene, especially when applied to soil, increased the concentrations of Zn nd Cr in lettuce leaves.
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