The accumulation of trace metals in the shells of bivalves allows quantitative assessments of environmental pollution and helps to reconstruct paleo aquatic environments. However, the understanding on how marine and freshwater mollusks control the level of trace elements in their shells remains very limited. Here, we compared the trace element composition of marine and freshwater bivalves from boreal and subarctic habitats, using examples of widely distributed species of marine (Mytilus edulis, M. trossulus) and freshwater (Anodonta anatina, Unio sp., Beringiana beringiana) mussels. Sizable differences in several trace element concentrations were detected between different species, depending on their environmental niches. A multiparametric statistical treatment of the shell’s elemental composition allowed to distinguish the impact of external factors (water and sediment chemical composition) from active metabolic (biological) control. In particular, the obtained results demonstrated that Ba:Ca and Pb:Ca ratios in mussels’ shells are closely related to the primary productivity of aquatic ecosystems. The Mn:Ca ratio allowed to constrain the environmental conditions of mussels’ species depending on the trophic state of inhabited waterbody. Overall, the marine mussels exhibited stronger biological control of trace element accumulation, whereas trace element pattern in shells of freshwater mussels was chiefly controlled by environmental factors. The obtained results might help to use the trace element composition of bivalves in distinguishing marine and freshwater habitats of mollusks in paleo environments.

The Suhoe Sea Gulf is a unique White Sea water body. Taking into account the risk of contamination of the White Sea with radionuclides as a result of the activities of the domestic and foreign nuclear industry and considering the plans to construct a deep-water part of the Arkhangelsk port on the Kuya River, the content and distribution patterns of natural and man-made radionuclides in the bottom sediments of the Suhoe Sea Gulf need to be studied. The specific activity of radionuclides was measured using a PROGRESS-2000 gamma spectrometer. Statistical processing of the data was performed using the STATISTICA (data analysis software system), version 10 software by StatSoft, Inc. (2011). The average specific activity of²²⁶Ra,²³²Th and⁴⁰K was 6.5 ± 1.4, 14.2 ± 4.3, 416 ± 89, accordingly.¹³⁴Cs and¹³⁷Cs were detected in 4 and 5 samples with a mean specific activity value of 3.3 ± 1.6 and 3.5 ± 1.1, respectively. The highest specific activity values of⁴⁰K are confined to the pelitic deposits. The main driving force in the processes of accumulation and redistribution of²³²Th is gravitational water accumulation and mechanical transfer. The measured values of the specific activity of radionuclides do not exceed those previously determined by other authors in the bottom sediments of the White Sea. Correlation analysis showed a significant relationship between the content of¹³⁴Cs and¹³⁷Cs (0.77, p = 0.05),²³²Th and⁴⁰K (0.67, p = 0.05) and¹³⁷Cs and⁴⁰K (0.84, p = 0.05). Factor analysis allowed two groups of radionuclides to be identified, their content being is determined by different processes:¹³⁴Cs,¹³⁷Cs, and⁴⁰K are jointly controlled by the most powerful factor (50%) and²³²Th is affected by the weaker factor (29 %). Both factors are based on natural processes of radionuclide receipt and redistribution: the first factor reflects the ability of bottom sediments to adsorb⁴⁰K and isotopes of cesium, which are similar in chemical properties, and the second one reflects the natural process of removal by rivers of²³²Th with terrigenous material.

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.

Concentrations of the chemical elements were analyzed in the shells of a bivalve mollusk species (Beringiana beringiana), water, and bottom sediments from seven lakes located on the Kamchatka Peninsula, the Kurile Islands, Sakhalin Island, and Primorsky Krai (Northeast Asia). A principal component analysis allowed to determine three factors those were related to environments in the waterbodies. We revealed two groups of samples corresponding to large geographical regions using the determined factors. Statistically significant differences were found between geographical groups of samples, and higher values of element distribution coefficients were determined for samples from lakes on the Kamchatka Peninsula. The highest concentrations of lithophilic elements were measured in the shells from Lake Kurazhechnoye (Kamchatka Peninsula). The highest concentrations of Al and Mg were detected in shells from Lake Peschanoye (Kunashir Island). In Lake Chernoye (Sakhalin Island), the highest concentrations of Sr and Sb in the shells were detected. Zn, Fe, Pb, and rare earth elements were present in large concentrations in the shells from Lake Vaskovskoye, Primorsky Krai. The shells of the Beringian freshwater mussel show large phenotypic plasticity, and their shape demonstrates significant relationships with various environmental parameters, that were assessed based on the geochemical indicators.

The article presents data on the elemental and functional composition of humic acids, their molecular weight characteristics, physical, chemical and acid-base properties. The sorption properties of humic acids towards Cd2+ and Pb2+ are studied. The relationship between the polyelectrolyte nature of humic acids and their sorption capacity is revealed.

Although the Arctic territories have long been considered “the gold standard of purity”, global climate change and environmental pollution are having a significant impact on the state of Arctic ecosystems. In particular, industrial complexes combined with transboundary transport are having a negative impact. The aim of this work is to determine the contribution of atmospheric Pb to the contamination of soils of the Arctic territories using the trajectory statistics method which combines correlation and factor statistical processing approaches while taking the actual lead content in the upper soil horizon into account. In order to assess the transfer of pollutants, an analysis of multiannual air mass tracts and impurity transfer trajectories to certain points was carried out. The objects of study are the soil of the Khorey-Ver settlement, the basin of the Shapkin and Sula rivers, northeastern and southern Svalbard and the islands of the Southern Archipelago of Novaya Zemlya. It was established that the primary contribution to airborne pollution of the Nenets Autonomous District (NAO) during the summer period comes from sources located within a radius of about 400 km. Aerogenic influence of the mainland on the territory of Svalbard is practically absent, with the main atmospheric transport of substances coming from nearby marine areas. The transfer of impurities from the mainland to the Novaya Zemlya District is also insignificant. During the summer months, there is practically no airborne lead contamination of the island territories. Some influences on the territory of Novaya Zemlya and the NEO can be traced to sources on the Kola Peninsula, the coasts of the Barents and Kara seas, as well as long-distance transport from the southern regions. On the territory of the NAO, the number of heavy metal (HM) precipitations increases from west to east, possibly indicating a stronger impact of emissions from the Norilsk industrial hub than from the enterprises of the Kola Peninsula on this territory. In terms of seasonal dynamics, the island points are characterised by an increase in HM fluxes during the winter period; conversely, for the NAO territory, such an increase takes place during the summer. This discrepancy is primarily due to the changing nature of the atmospheric circulation.