Polyaromatic Hydrocarbons in Rhizosphere Soil of Different Plants: Effect of Soil Properties, Plant Species, and Intensity of Anthropogenic Pressure

Abstract

The objective of the present study was to determine the content of polycyclic aromatic hydrocarbons (PAH) in the rhizospheres of some selected plant species (Cucumis dativus, Daucus carota, Allium cepa, Cueurbita, Petroselinum sativum, Cucurbitaceae, Phaseolus vulgaris, Beta vulgaris, Apium graveolens, Allium porrum, Vicia faba). Various anthropogenic influences on the PAH content in the rhizospheres of the three species selected were also studied. The PAH content was determined using the high performance liquid chromatography (HPLC) method with ultraviolet (UV) detection after a preliminary sample treatment with ultrasonic techniques. On the basis of the PAH content, the organic carbon content and the value of log Koc, a potentially bioavailable PAH fraction present in the rhizospheres of the plants studied, were calculated. The lowest content of the PAH sum (<1100 µg/kg) was found in the Petroselinum sativum, Cucurbitaceae, and Allium porrum rhizospheres. The content of the compounds studied was more than 67% lower than in the control soil (3307 µg/kg). Moreover, in the rhizosphere of the Allium porrum, the lowest content of all the five‐ and six‐ring PAH samples studied was found. The contribution of the 16 PAHs' sum, determined on the basis of an equilibrium partition in all rhizospheres studied, was higher than in the control soil. The evaluation of the PAH content in the rhizospheres of the three plants as related to the influence of anthropogenic sources showed a higher PAH content in them than in the control soil. The evaluation of the relation between the PAH content and the soil properties studied showed only sporadically statistically significant correlations.