Polycyclic aromatic compounds in marsh and watershed soils of the Barents Sea coastline

We studied the PAH profiles in the soils of the marsh areas along the Barents Sea coast and found that the PAH content in the study area is low and corresponds to background levels. Peat soils contained more PAHs than organomineral soils, which is due to the characteristics of their historical formation. PAHs in soils along the Barents Sea coast are of petrogenic origin. The main sources of PAHs in marsh soils are guano, macrophytobenthos and plastic waste. The soils of the water catchment areas were of more natural pedogenic origin. The composition of PAHs in soils of the low and middle marshes is significantly influenced by sea tides bringing organic matter. The PAH composition of the high marshes and areas at the boundaries of the watersheds in the ecotone strip is determined by the composition of the vegetation and the presence of peat formation. Cluster analysis data show that soil type has a greater influence on PAH composition than proximity to the sea. The accumulation and migration of PAHs in soil profiles of organomineral soils is influenced by the salinity and granulometric composition of the soils and, to a lesser extent, by the organic carbon and nitrogen content. In organogenic soils, the content of organic matter and the degree of decomposition of peat are the main factors influencing the composition of PAHs. Permafrost acts as a barrier to the migration of PAHs to the underlying layers. Significant accumulation of PAHs is observed at the boundary of the seasonally thawed layer (STL).