The total content of polycyclic aromatic hydrocarbons (PAHs) in the peat of a palsa near Eletsky settlement, Vorkuta urban district, Komi Republic, varies from 11 to 360 ppb, with an average of 63 ppb. Heavy compounds, such as benzo(a)anthracene and benzofluoranthenes, are prevalent among PAHs. Benzo(a)anthracene decreases with depth, while benzofluoranthenes increases. The presence of PAHs in the peat is determined by three main factors: technogenic impact, wildfires, and biogeochemical soil processes. The prevalence of benzo(a)anthracene in the upper part of the palsa down to the bottom of the active layer suggests an anthropogenic impact (the influence of transport and domestic fuel combustion). Two sharp peaks of PAHs content (260 and 360 ppb) are observed; they coincide with a local increase of carbon isotope values, most likely resulting from wildfires. The minimums in PAHs content are presumably determined by the biogeochemical factor and the input of polyarenes generated by decomposition of plant residues.

PAHs were analyzed by high performance liquid chromatography. The preparation of samples started from the extraction with dichloromethane (20 mL per 1 g dry peat). The resulting extract was filtered, evaporated, re-extracted with hexane, and purified using modified silica gel Diapak-C cartridges. The air-evaporation was performed to dryness. The purified extracts were also evaporated and re-extracted with acetonitrile. PAHs were analyzed in an Agilent 1260 at the Analytical center of the Faculty of Soil Science, Moscow State University.