Level, distribution and sources of Np, Pu and Am isotopes in Peter the Great Bay of Japan sea.

Transuranium elements such as Np, Pu and Am, are considered to be the most important radioactive elements in view of their biological toxicity and environmental impact. Concentrations of Np, Pu isotopes and Am in two sediment cores collected from Peter the Great Bay of Japan Sea were determined using radiochemical separation combined with inductively coupled plasma mass spectrometry (ICP-MS) measurement. The Pu and Am concentrations in all sediment samples range from 0.

Radionuclides' Recovery from Seawater Using FIC and FIC A Sorbents.

To solve radioecological and oceanological problems (estimate the vertical transport, flows of particulate organic carbon, phosphorus biodynamics, submarine groundwater discharge, etc.), it is necessary to determine the natural values of the radionuclides' activity in seawater and particulate matter. For the first time, the radionuclides' sorption from seawater was studied using sorbents based on activated carbon modified with iron(III) ferrocyanide (FIC) and based on activated carbon modified with iron(III) hydroxide (FIC A-activated FIC) obtained by FIC sorbent treatment with sodium hydroxide solution.

Bottom sediment radioactivity of the six Caucasus lakes located in different altitude zones.

Natural and artificial radioactivity of bottom sediment in the six lakes of the Western and Central Caucasus have been evaluated. It allowed to define the variation of sedimentation rate during the last 100-150 years using technogenic (Cs) and natural (Pb, Ra) radionuclides as a chronomarkers. The studied lakes are located in the contrasting geographic conditions, different orographic positions, and have different origin.

Biogeochemical Factors of Cs, Sr, U, Pu Immobilization in Bottom Sediments of the Upa River, Located in the Zone of Chernobyl Accident.

Laboratory modeling of Cs, Sr, U, Pu immobilization by phytoplankton of the river Upa, affected after the Chernobyl accident, has been carried out. Certain conditions are selected for strong fixation of radionuclides in bottom sediments due to biogeochemical processes. The process of radionuclide removal from the water phase via precipitation was based on their accumulation by phytoplankton, stimulated by nitrogen and phosphorus sources.

The anthropogenic fallout radionuclides in soils of Mount Khuko (the Western Caucasus) and their application for determination of sediment redistribution.

The purposes of this study are to determine the content and origin of anthropogenic fallout radionuclides (FRN) in soils of Mount Khuko, located in the western sector of the Caucasus Mountains and to assess the possibility to use them for evaluation of sediment redistribution for the alpine grasslands,. The field study was carried out in August 2019 near the top of Mount Khuko, located in the western part of the main Caucasus Mountain Ridge. Integral and incremental soil samples were collected from the different morphological units of the studied area.

Biometric traits of onion (Allium cepa L.) exposed to Cs and Am under hydroponic cultivation.

To elucidate the features of bioaccumulation and phytotoxic effects of long-lived artificial radionuclides, a hydroponic experiment was carried out with the cultivation of onion (Allium cepa L.) in low-mineralized solutions spiked with Cs (250 kBq L) or Am (9 kBq L). After the 27-day growth period, ≈70% of Cs and ≈14% of Am were transferred from the solutions to onion biomass with transfer factor values ≈ 400 and ≈ 80, respectively.

Use of natural and artificial radionuclides to determine the sedimentation rates in two North Caucasus lakes.

The specific activities of natural (Pb, Ra, and Th) and artificial (Cs, Pu, and Am) radionuclides in the sediments of two North Caucasus lakes were determined. The two lakes, Lake Khuko and Lake Donguz-Orun, differ in their sedimentation conditions. Based on the use of unsupported Pb and both Chernobyl-derived and bomb-derived Cs as chronological markers, it was established that the sedimentation rates in Lake Khuko over the past 55-60 y did not exceed 0.