Composition and source of polycyclic aromatic compounds in deposited dust from selected sites around the Upper Silesia, Poland

Abstract

About 300 polycyclic aromatic compounds were identified using the GC-MS method in deposited dust collected in sites located outside the industrial belt of the Upper Silesia agglomeration. Concentrations of selected polycyclic aromatic hydrocarbons (PAH) range from 6.8 ug/g dust for anthracene to 142 ug/g dust for fluoranthene. Concentrations of highly carcinogenic PAH e.g. benzo(a)pyrene, benzofluoranthenes and benzo(a)anthracene range from 49 to 145.5 ug/g of dust. Significant concentrations (up to 35 ug/g of dust) of carcinogenic C22H14 PAHs (m/z 278) and C24H14 PAHs (m/z 302) were determined in all samples. Aromatic ketones and quinones as well as aromatic nitrogen and sulphur compounds with concentrations ranging from 2 to 45 ug/g of dust, were found in the polar NSO fraction. Molecular composition of hydrocarbons in the deposited dust is characteristic of the terrestrial organic matter, as suggested by the presence of long chain n-alkanes with odd carbon skeleton predominance. However, relatively high concentrations of steranes and distribution of homohopanes different from terrestrial organic matter suggest that part of extractable organic matter may be from diesel engine exhausts and/or paved road dust. The origin of the organic compounds adsorbed on the deposited dust is related to not complete coal combustion and possibly to other sources, such as automobile exhaust. The occurrence of phenyl-polyaromatic hydrocarbons and polyphenyls such as terphenyls, phenylnaphthalenes and their methyl derivatives, phenylphenanthrenes, phenylfluoranthenes and/or phenylpyrenes results from the free radical phenylation of aromatics during organic matter combustion.