Carbon Isotope Signatures and Polyarenes in the Pedogenic Material of Ice Wedges of the Batagay Yedoma (Yakutia)

The carbon isotope signatures and the content of polycyclic aromatic hydrocarbons (PAHs) in the pedogenic material of inclusions in ice wedges of the Batagay yedoma (Yakutia) are studied. The mean concentration of 11 PAHs is 170 ppb (minimum, 7 ppb and maximum, 430 ppb) and the mean δ13С value in soil lipids is -29‰ (minimum, -31.1‰ and maximum, -26.2‰). The prevalent polyarenes in associations are naphthalene homologs and phenanthrene. Trace amounts of heavy PAHs, including benzo[a]pyrene (an indicator of pyrogenic processes), are also detectable. The PAH contents and δ¹³С values in ice wedges show the trend of a decrease with depth. The δ¹³С values and PAH content suggest a pedogenic origin of the deposit: therefore, PAHs originate from plant residues and wildfires. The observed trend of changes in the concentrations of polyarenes along the ice wedge may be associated with the changes in landscapes in the Late Pleistocene.