Accumulation of Polycyclic Aromatic Hydrocarbons in Hummocky Tundra Peatlands under Climate Change at High Latitudes

The quantitative and qualitative compositions of polycyclic aromatic hydrocarbons (PAHs) were determined, and the vertical stratification of PAHs was characterized along profiles in hummocky tundra peatlands. In perennially frozen peat layers, PAHs occur in a conserved state and do not undergo transformation in contrast to seasonally thawed layers. Statistically significant correlations were detected between the mass fraction of 5-6-ring structures (especially, benzo[ghi]perylene), individual PAHs, and botanical composition of the peat at the thawing-freezing boundary; and profile relations for various combinations of PAHs were calculated. The radiocarbon and paleobotanical analysis of peatlands in combination with the obtained results can be used for assignment of initial vegetation to periods of peat formation in the Holocene and as markers of the response of the peatland permafrost to climate changes at high latitudes.