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In the conditions of climate warming, the thawing of permafrost can provoke the formation of new thermokarst lakes and subsidence, which facilitates the removal of organic matter from thawed peat into natural waters. Hydrochemical studies of surface waters of the Bolshezemelskaya tundra have demonstrated the exponential dependence of the physicochemical parameters on the size of the water body (peat subsidence, thaw ponds, small lakes, thermokarst lakes). The hydrochemical features of thermokarst lakes of the Bolshezemelskaya tundra are determined by high content of DOC, surface runoff and the thickness of peat deposits. Measurements of concentrations and fluxes of methane showed that all studied water bodies of the Bolshezemelskaya tundra are oversaturated with CH4, and depressions, subsidence, and small water bodies (<100 m2) are characterized by the highest concentrations of DOCs. The contribution of these small reservoirs to the total coverage of the surface of the Bolshezemelskaya tundra area is significant, and their consideration can greatly change the assessment of methane fluxes from the arctic tundra.

The goal of the research is to find out the main low-intensity radioactive anomalies as the main probable source of human light irradiation in Arkhangelsk city; give an objective estimation of radiation risks and potential health damage of the local population. Avtogamma-spectrometric method, using a mobile radiation monitoring system RS-700 was firstly used in the city. It allows to measure both natural and artificial radionuclides in real time geo-referenced. Ground gamma survey method with geological prospecting scintillation radiometer SRP-88H has been used for specification of obtained results. Soil sampling has been selected in each city block with further definition of radionuclides specific activity in the gamma spectrometer counting sample "Progress". A unique set of data on the radioactive level and the specific activity of 137Cs, 40K, 232Th, 226Ra in the soil have been collected as a part of the radio-ecological study. Nine local low-intensity anomalies have been revealed and their genesis has been set. The comparative comprehensive assessment of low doses ionizing radiation on human health has been done. Possible ways of further medical and environmental research in the field of oncological diseases and radioactivity study in the city of Arkhangelsk have been planned.

(1) Background: The Quaternary river bank deposits of the European North of Russia contain several mollusk fossils that can give important past-climate information which is relevant to understand the evolution of climate in the Holocene period and predict future scenarios on climate change. (2) The purpose of the research: reconstruction of the main physical and chemical parameters of the habitat of mollusks based on the determination of the species of mollusks and the study of the isotope-geochemical composition of shells and their host deposits. (3) Object of study: Quaternary deposits of coastal outcrops of the rivers of the European North of Russia: Pechora Sula, Peza, bivalve shells, and their fragments. (4) Results: The revealed macrofauna complexes represented by bivalves (Arctica islandica, Hiatella arctica, Mytilus edulis, Tridonta borealis, Mya truncata, Neptunea despecta) were determined and the variations of δ13C and δ18O (‰) isotopes in the studied fossil bivalve shells were calculated. The data on the concentrations of chemical elements in fossil shells were determined and summarized. The content of elements in mollusk shells varied within the following limits: Fe 101.7 −403.3 µg/g (Vastyansky Kon’, river Pechora), Mg 0.38–2.61 µg/g (Vastyansky Kon’, river Pechora), Ba 18.27–60.44 µg/g (village Oksino-River Sula), and Sr 1128.3–2275.34 µg/g (Vastyansky Kon’-village Oksino, river Pechora). The ratio between the elements varies within Ba/Sr 0.011–0.041 (village Oksino- River Sula) and Mg/Fe 0.01–0.15 (Vastyansky Kon’- village Oksino, river Pechora).