Accumulation of Polyarenes in Plants of Peatlands on the Coast of the Barents Sea
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CHEMISTRY
Accumulation of Polyarenes in Plants of Peatlands on the Coast of the Barents Sea E. V. Yakovlevaa, *, D. N. Gabova, and A. N. Panyukova aInstitute
of Biology, Komi Science Center, Ural Branch, Russian Academy of Sciences, Kommunisticheskaya 28, Syktyvkar, 167982 Russia *е-mail: [email protected] Received March 3, 2020; revised April 20, 2020; accepted April 24, 2020
Abstract—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. Keywords: polycyclic aromatic hydrocarbons, plants, decomposition, peatlands, Hemic Folic Cryic Histosol, Fibric Floatic Cryic Histosol DOI: 10.1134/S1064229320110137
INTRODUCTION It is commonly believed that peat comprises readily degradable compounds, for example, polysaccharides; relatively stable substances, such as lignin and complex aromatic compounds; and the products of their mutual transformation and combination, such as humic substances. Peat is formed via accumulation and degradation processes acting on the plant residues. After dying off, vegetation is aerobically decomposed; with accumulation of the peat layer, the aerobic conditions are replaced by anaerobic ones [17]. The chemical composition of peat is a combination of the chemical compositions of bog plant and microbial tissues, soil water, and secondary substances formed during its decomposition. A considerable amount of polycyclic aromatic hydrocarbons (PAHs) is present in peat; PAHs are organic compounds of the benzene series having either natural or anthropogenic origin. On one hand, PAHs are super-ecotoxicants [18, 19, 21, 23]; on the other hand, they are the organic components necessary for plants. A high chemical stability of PAHs in combination with an acid and anaerobic medium of peatlands inter-
feres with their degradatio
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