The results of studying tar balls on Baltic Sea beaches (the summer of 2008) are given with their comparison with other coastal areas. Tar balls in concentrations of 0.01–1.2 g/running m on the beaches of Sambiiskii Peninsula are found to correspond to a mean level of beach pollution. It is shown that, in addition to weathering, even high-molecular homologues in the composition of tar balls are rapidly decaying. Therefore, the molecular markers currently in use are not unequivocal indicators to the origin of hydrocarbons.

The study of bottom sediments from water bodies of the Norilo-Pyasinsk water system (July 29–August 13, 2020), following the accidental diesel fuel (DF) spill in Norilsk on May 29, 2020, has shown that the mean content of aliphatic hydrocarbons (HCs) decreased in the following sequence (µg/g): mouth of the Ambarnaya River (1914, σ = 3428) > Bezymyannyi Creek–the Daldykan River–the Ambarnaya River (1000, σ = 1351) > the Pyasina River (27, σ = 17) > Pyasino Lake (15, σ = 6). The pollution was spread from the spill site by the river flow over a distance of 31 km and did not enter Pyasino Lake. As a result of transformation, the composition of aliphatic HCs in bottom sediments differed from the composition of HCs in the DF even in the most polluted areas. The content of polycyclic aromatic hydrocarbons (PAHs) sharply decreased with distance from the pollution source (from 3865 to 56 ng/g). Their composition was mainly petroleum-based with naphthalene HCs accounting for 46–53% of total polyarenes. Naphthalene HCs dominated not only in sediments of the Ambarnaya and Daldykan rivers, but also in the Norilka River and in the mouth of the Pyasina River, which could have been caused by other pollution sources (barrels of fuels and lubricants and water transport).

The results of the study of hydrocarbons (HCs): aliphatic (AHCs) and polycyclic aromatic hydrocarbons (PAHs) in bottom sediments (2019 and 2020, cruises 75 and 80 of the R/V Akademik Mstislav Keldysh) in the Norwegian-Barents Sea basin: Mohns Ridge, shelf Svalbard archipelago, Sturfiord, Medvezhinsky trench, central part of the Barents Sea, Novaya Zemlya shelf, Franz Victoria trough are presented. It has been established that the organo-geochemical background of the Holocene sediments was formed due to the flow of sedimentary material in the coastal regions of the Barents Sea on shipping routes. The anthropogenic input of HCs into bottom sediments leads to an increase in their content in the composition of C_org (in the sandy sediments of the Kaninsky Bank at an AHC concentration up to 64 μg/g, when its proportion in the composition of C_org reaches 11.7%). The endogenous influence on the of the Svalbard archipelago shelf in Sturfiord and in the Medvezhinsky Trench determines the specificity of local anomalies in the content and composition of HCs. This is reflected in the absence of a correlation between HCs and the grain size composition of sediments and C_org content, as well as a change in hydrocarbon molecular markers. At the same time, the sedimentary section is enriched in light alkanes and naphthalene’s that may be due to emission during point discharge of gas fluid from sedimentary rocks of the lower stratigraphic horizons and/or sipping migration.