Accumulation of polycyclic aromatic hydrocarbons in hummocky tundra peatlands under climate change at high latitudes

Polycyclic Aromatic Hydrocarbons and Carbon Isotopes in a Palsa Peat (Bol’shezemel’skaya Tundra)

“…The studied territory is near the objects with anthropogenic influence, such as the railroad and an urban-type settlement with furnace heating. These factors affect the PAH content in the palsa sites mainly in the upper peat layers, in particular, the near-surface maximum is most likely determined by this effect, which is confirmed by the presence of a maximum fluoranthene (regarded as a "technogenic" PAH [8]) concentration in the near-surface sample. Most researchers regard benzo(a)anthracene as a technogenic product; note that this compound in the examined palsa was also the prevalent PAH in the peat at the depth of 0 to 60 cm, i.e., to the active layer bottom.…”

“…A comparison of our data to the relevant literature demonstrates that the PAH content in the examined peat palsa is rather low. For example, the PAH concentrations of 160 to 8655 ppb were recorded in the peat palsa near the village of Seida [8] versus the values of 10-360 ppb observed in the palsa near Eletsky settlement. The values recorded in the palsa site are more characteristic of the mineral soils near the village of Seida [7].…”

“…A natural biogeochemical origin of PAHs is also possible. Although our knowledge about this phenomenon is rather vague, polyarenes are abundant in the landscapes unaffected by anthropogenic activities [8,9,12,13,16]. As has been shown [11], light polyarenes (3-ring phenanthrene and its alkyl derivatives) are prevalent in the PAH composition of peat bodies under natural conditions.…”

Polycyclic aromatic hydrocarbons in permafrost peatlands

“…The results reported here, based on peat plateaus in European Northeast (sites K 1, К 2 and I 3), confirm our previous findings that the PAH concentration is much lower in the active layer of peat plateaus, than in those in permafrost, which indicates the onset of aerobic conditions and ongoing biodegradation 29 . A significant increase in PAH content is due to highly condensed 5–6-nuclear polyarenes, and especially anomalously high concentrations of 6-nuclear benzo[ ghi ]perylene, at the transitional layer, the border between the lower active layer (35–60 cm) and the upper permafrost (60–80 cm), in the peat plateaus of the European forest-tundra 67 . The quantitative and qualitative analysis of PAHs at the boundary between the active layer and the upper permafrost can be used as a response indicator of permafrost on climate change at high latitudes, since the permafrost degradation leads to the transformation of preserved plant residues, humic substances, nonspecific organic compounds, and accumulation of heavy PAH structures 67 .…”

“…A significant increase in PAH content is due to highly condensed 5–6-nuclear polyarenes, and especially anomalously high concentrations of 6-nuclear benzo[ ghi ]perylene, at the transitional layer, the border between the lower active layer (35–60 cm) and the upper permafrost (60–80 cm), in the peat plateaus of the European forest-tundra 67 . The quantitative and qualitative analysis of PAHs at the boundary between the active layer and the upper permafrost can be used as a response indicator of permafrost on climate change at high latitudes, since the permafrost degradation leads to the transformation of preserved plant residues, humic substances, nonspecific organic compounds, and accumulation of heavy PAH structures 67 . However, in the European key areas I 1 and I 11, such a pattern is not expressed, and in the upper aerobic horizons of the active layer, the PAH concentrations are quite high, and in the upper horizons of the West Siberian sites, the content of light polyarenes can be maximum compared to the lower ones.…”