Organic and suspended substances in the Bolshoy Shantar Island ecosystems

The organic matter characteristics (including priority polycyclic aromatic hydrocarbons, PAHs) and suspended matter in the Bolshoy Shantar Island surface waters and snow cover are given in the paper. The dry combustion method (TOC-ve analyzer) has revealed elevated contents of total (Corg) and dissolved organic carbon in watercourses, and low Corg contents in snowmelt waters. A low content of suspended solids in the depositing media has been determined using the gravimetric method. The high-performance liquid chromatography analysis shows that Σ11PAHs concentration in the snow, collected on the Bolshoy Shantar Island in May 2017, reached on average 23.64 ng/dm3, while in the water of the Olenya River in summer 2018, the content of Σ10PAHs was 14.78 ng/dm3. The markers, based on the ratios of individual PAHs, identified pyrogenic and mixed sources of polyarenes entering the depositing environments. The total toxic benzo(a)pyrene equivalent in snowmelt and in the Olenya River water was 0.084 and 0.029 ng/L, respectively. The main contributors to the total river water and snowmelt PAH toxicity are benzo(a)anthracene (41%), phenanthrene (24%), benzo(a)pyrene (36%), benzo(a)anthracene (24%), and phenanthrene (19%), respectively. The quality of snow and river water, contaminated with polyarenes on the island, is satisfactory. It is recommended to continue and expand monitoring of both natural environments (bottom sediments, sea waters, etc.) and pollutants (hydrocarbons, including petroleum products, aliphatic and aromatic compounds, etc.). They are in need of comprehensive assessment and their state forecasting, being under the influence of anthropogenic factors.