Content of potentially bioavailable polycyclic aromatic hydrocarbons in rhizosphere soil in relation to properties of soils

Abstract

The aim of the present study was to evaluates the content of mild-solvent extracted fraction of the polycyclic aromatic hydrocarbons in the rhizospheres of some selected plant species (Cucumis sativa, Daucus carota, Allium cepa, Cucurbita pepo, Petroselinum sativum, Cucurbita sp., Phaseolus vulgaris, Beta vulgaris, Apium graveolens, Allium porrum, Vicia faba). Ten compounds from the US EPA list (phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chryzene, benzo[b]fluoranthene, benzo[a]pyrene, benzo[ghi]perylene oraz indeno[1,2,3-cd]pyrene) were chosen. The polycyclic aromatic hydrocarbon (PAH) content was determined using the HPLC method with 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, (equilibrium partitioning model) a soil pore water PAH fractions present in the rhizospheres of the plants studied were calculated too.The content of the fraction extracted with n-butanol within the total of 10PAHs ranged from 55% to 90% (mean 74%). Similarly, as in the case of the total of the 10 PAHs, significant differences in the content of PAHs extracted with n-butanol were also noted for the individual compounds studied. The content of the total of the 10 PAHs as determined from equilibrium partitioning model in relation to plant species ranged from 0.03 to 0.18μg/kg which constituted from 0.07% to 0.15% of the total content of these compounds. No clear relations between soil properties and the content or contribution of potentially bio-available PAH fractions have been observed.