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Being a global pollutant, mercury can originate from both natural as well as anthropogenic sources. Coastal marine atmospheric fog is considered a potential source of ocean-derived monomethylmercury (MMHg) to coastal terrestrial ecosystems. However, the ratio between mercury appearing through natural processes and that from the results of human activity is unclear. We assumed that the total mercury content in the fur of tigers would differ depending on the distance from the sea. Here we show that the average mercury content in tigers from the coast (0.435 ± 0.062 mg kg−1) is significantly different from tigers from the inland area (0.239 ± 0.075 mg kg−1), (p = 0.02). We found that the content of mercury in the fur of tigers is largely dependent of natural processes rather than human activity. We assume that the levels of mercury in coastal ecosystems in the south of the Russian Far East reflect the position of the region relative to the deep faults of the East Pacific Platform. Obtained data indicate that environmental risks associated with mercury pollution currently exist, but do not pose a serious threat to Siberian tigers.

Bioaccumulation of mercury in the food chain can pose a threat to human health. Therefore, in our article, we obtained data on the concentrations of mercury in the tissues of wild animals, which are a food resource for humans. We determined the mercury concentrations in liver, kidneys, muscles and hair of wild boar and moose, which are consumed by the population of the Russky Sever National Park. The average mercury concentrations in moose tissues ranged from 0.004 mg / kg wet weight in muscles to 0.079 mg / kg wet weight in kidneys. The average concentrations of mercury in boar tissues ranged from 0.136 mg / kg wet weight in wool to 0.711 mg / kg wet weight in kidneys. The main trends of mercury bioaccumulation in the tissues of moose and wild boar were determined.

The article compares mechanical parameters, group chemical compositions, iron content, lipid compositions before and after saponification, moisture, bulk density in three parts of Betula pubescens Ehrh. birch wooden parts: sapwood, false heartwood, false heartwood border. The strength properties of the false heartwood are worse than those of sapwood. The border of the false core is sometimes stronger than that of other parts. Evaluation is carried out in terms of hardness, flexural strength and compression strength. False heartwood, and even more so its border, contain more extractives extracted by ethanol, water, alkali solution, methylene chloride and less iron. The content of other components: cellulose, lignin, other polysaccharides differs, but less significantly. False heartwood border is heavier than the other wooden parts. Moisture content of the various parts decreases in the following order: false heartwood border, false heartwood, sapwood. The composition of the extractives extracted by methylene chloride is different in different parts. The composition is determined by gas-liquid chromatography-mass spectrometry before and after saponification of esters. Differences in sterols are given. An increased content of monoterpene alcohols and arylheptanoids is observed at the border. Differences in the properties of different wooden parts of a tree are explained by different amount and composition of extractives.