Polycyclic aromatic hydrocarbons in the Siberian Arctic seas sediments.

Polycyclic Aromatic Hydrocarbons (PAHs) are among the main persistent organic pollutants in the Arcticwhich enter the polar region from lower latitudes by air transport and ocean currents and accumulate in marine sediments. This work represents the first study in 25 years of the least studied and hard-to-reach areas of Siberian arctic seas. Sixteen priority PAHs as well as 1- and 2-methylnaphthalenes were analyzed by gas chromatography - tandem mass spectrometry in the twenty-four sediment samples taken from Kara, Laptev and East Siberian Seas in October 2020. The obtained sum concentrations ranged from 31 to 223 ng/ g with the greatest contribution of phenanthrene, benzo[b]fluoranthene, benzo[k]fluoranthene, as well as naphthalene and its methyl derivatives while the greatest PAH levels were observed in Laptev Sea. No correlations between sum PAH concentration, total organic carbon and black carbon contents were found. The toxic equivalent in benzo[a]pyrene units was from 2.2-18.2 ng/ g that shows the general safe environmental situation in the region. The overall PAH level is comparable with the data obtained in 1990s which indicates a long-term persistence of pollution despite an overall decline in global PAH emissions. The main sources of PAHs involve mainly coal/biomass and liquid fuel combustion with weaker contribution of petroleum sources.

Data of polycyclic aromatic hydrocarbons concentration in the Siberian Arctic seas sediments.

Polycyclic Aromatic Hydrocarbons (PAHs) are one of the most dangerous persistent organic pollutants in the Arctic. They have different sources and pathways of entering in to the environment. Because of their lipophilic properties, PAHs can easily accumulate in marine sediments. This work gives a new data about concentration of PAHs in Siberian arctic seas. Sixteen priority PAHs as well as 1- and 2-methylnaphthalenes were analyzed by gas chromatography - tandem mass spectrometry in the twenty-four sediment samples taken from Kara, Laptev and East Siberian Seas in October 2020. The obtained sum concentrations ranged from 31 to 223 ng g-1 with the greatest contribution of phenanthrene, benzo[b]fluoranthene, benzo[k]fluoranthene, as well as naphthalene and its methyl derivatives while the greatest PAH levels were observed in Laptev Sea. The toxic equivalent in benzo[a]pyrene units was from 2.2-18.2 ng g-1. Total organic carbon (TOC) and black carbon (BC) content in arctic were in the ranges of 0.18-1.98 % and 0.03-0.40 %, respectively. The overall PAH level shows negligible harm to the environment.

Data on the spatial distribution of 1,1-dimethylhydrazine and its transformation products in peat bog soil of rocket stage fall site in Russian North.

The data set covers the results of a study of 96 samples of peat bog soil from the fall place of the first stage of the Cyclone-3 launch vehicle contained unburned toxic rocket fuel 1,1-dimethylhydrazine (UDMH) in the European North of Russia. Soil samples were taken during a helicopter expedition to the "Koida" fall region of Plesetsk Cosmodrome operation zone in October 2015 at different distances from the center of the fall site and from different soil horizons. Samples were analyzed by liquid chromatography with amperometric detection and gas chromatography - tandem mass spectrometry. The contents of UDMH and the ten most important products of its transformations (methylhydrazine, hydrazine, 1,1,4,4-tetramethyltetrazene, formaldehyde, acetaldehyde and furaldehyde N,N-dimethylhydrazones, 1-formyl-2,2-dimethylhydrazine, N,N-dimethylformamide, N-nitrosodimethylamine, and 1-methyl-1H-1,2,4-triazole) were determined. The obtained data reflect the spatial distribution, migration and transformation of UDMH in the fall places of rocket stages under conditions of subarctic which is discussed in related research article "Migration and transformation of 1,1-dimethylhydrazine in peat bog soil of rocket stage fall site in Russian North" [1]. They can be further used for understanding the UDMH transformation pathways in soils rich in organic matter and assessment of environmental impact of space rocket activities in high latitudes.

Migration and transformation of 1,1-dimethylhydrazine in peat bog soil of rocket stage fall site in Russian North.

An ingress of highly toxic rocket fuel 1,1-dimethylhydrazine (UDMH) and its transformation products into environment represents a serious negative impact on the ecosystem, as well as human health. The present research demonstrates the first data on the spatial distribution and quantification of UDMH and its main transformation products (methylhydrazine, hydrazine, 1,1,4,4-tetramethyltetrazene, formaldehyde, acetaldehyde and furaldehyde N,N-dimethylhydrazones, 1-formyl-2,2-dimethylhydrazine, N,N-dimethylformamide, N-nitrosodimethylamine, and 1-methyl-1H-1,2,4-triazole) in the peat bog soil of the fall site in subarctic region. One hundred samples of peat bog soil and one sample of surface water were analyzed by the developed earlier methodology. The considerable amounts of UDMH and most of its transformation products were found at distances of not >10 m from the center of the fall site. The maximum concentration of UDMH was found near the center, where maximal permissible concentration (MPC) was exceeded 2400-fold. The greatest pollution was observed in the surface soil layer, while methylhydrazine, 1-methyl-1H-1,2,4-triazole, 1-formyl-2,2-dimethylhydrazine, formaldehyde and acetaldehyde N,N-dimethylhydrazones, and N,N-dimethylformamide were the major UDMH transformation products. With increasing distance from the center, the composition of the transformation products changes in favor of the last three compounds. Formaldehyde N,N-dimethylhydrazone and N,N-dimethylformamide are present in all soil samples and can be considered as reliable markers of contamination with rocket fuel. The surface water of the peat bog contained four UDMH transformation products in considerable concentrations, including extremely toxic N-nitrosodimethylamine. The processes of migration and transformation of UDMH in peat bog soil differ considerably from those in sandy soils. This is due to cold climate of subarctic zone, the reducing environment of peat bog, and strong binding of hydrazines to organic matter of peat, which prevents migration of pollutants and contributes to the long-term maintenance of high levels of soil pollution.