Accumulation of Polyarenes in Plants of Peatlands on the Coast of the Barents Sea

The accumulation of polycyclic aromatic hydrocarbons (PAHs) in the plants of tundra peatlands on the coast of the Barents Sea (Nenets autonomous okrug) has been studied. Two- and three-ringed polyarenes are prevalent in the plants on the coast of the Barents Sea with their share in the total PAH content varying from 81 to 97%. The highest total content of polyarenes is observed in Sphagnum lindbergii Shimp., Carex aquatilis Wahlenb., and Eriophorum russeolum Fr. The plants growing in tundra and forest-tundra have identical qualitative and quantitative PAH compositions allowing for extrapolation of our data to other peatlands in the reference areas. A tight correlation between the PAH compositions of the upper peat layers and the dominant plants in the botanical composition of peat is observed. The correlation coefficients decrease with depth, which is associated with the increasing degree of peat decomposition. No accumulation peaks of heavy PAHs are observed in the active and permafrost layers of the peat in the waterlogged hollows and peat mounds of the northern tundra peatlands, which determines a decrease in the total mass fraction of polyarenes in these peatlands by an order of magnitude in comparison with the forest-tundra peatlands. Presumably, this is related to a slowed down decomposition of lignin under tundra conditions.