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The majority of organic carbon (OC), nutrients, and dissolved trace elements in soil porewaters are present in the form of colloids which determine element transport, bioavailability, and overall impact on ecosystems. Climate warming and permafrost thaw in high latitudes will primarily affect the soil liquid phase thereby modifying delivery of colloids to the hydrological network and their role in C transport and emission. Here we studied colloids in peat porewaters across a natural gradient of sporadic, isolated, discontinuous and continuous permafrost zone in the Western Siberian Lowland (WSL), the largest peatland in the world. The depth of sampling and the microrelief (mounds and hollows) had a generally weak impact on the proportion of colloidal forms (3kDa 0.45 μm) of OC, major (Fe, Al, P, alkali and alkaline-earth metals) and trace elements (TE) including micronutrients (Zn, Mn, Ni, Co, Cu), toxicants (Sb, As, Cd, Pb) and geochemical tracers (trivalent and tetravalent cations). Considering all micro-landscapes together, there was no sizable change in the proportion of colloidal fraction of OC, Fe, Al, P, micronutrients and toxicants across the permafrost zones. The majority of colloidal forms of all elements of these groups were represented by a size fraction between 3 and 30 kDa and were essentially Fe-Al-organic compounds with an average Fe:Al:OC molar ratio of 1.9:1:308. Overall, the degree of impact from environmental factors on OC and metal distribution among various colloidal fractions can be classified as depth ≤ permafrost type < microlandscape. Applying a substitution “space for time scenario” for the climate warming and permafrost thaw in Western Siberia, we do not expect sizable changes in C and element colloidal status during active layer thickness increase and permafrost boundary shift northward. Future studies of colloids in peat ice (below the active layer) are needed to assess possible changes in delivery of C and metals from soil to rivers and onward into the Arctic Ocean under massive permafrost thawing in the WSL.

Small lakes in areas of intensive crude oil production may be susceptible to oil pollution arising from accidental spills and leaks, eventually leading to the pollution of bottom sediments. Effective cleaning of aquatic bottom sediments remains a challenge. Flotation is a potentially simple and reliable approach for the cleanup of bottom sediments without their excavation from the water body. Full-scale testing of flotation-based technology using the specially designed airlift plant allowed the cleaning of bottom sediments of an unnamed boreal lake (‘the lake’) within the Samotlor oil field, North Russia, heavily polluted with crude oil several decades ago. The lake bottom sediments are dominated by peat and unevenly polluted with oil. The average oil content in the lake bottom sediments was 111 g kg−1. During the 1.5 months' field test in July–August 2018, the average total oil concentration in the bottom sediments of the lake was reduced to 1.99 g kg−1. Secondary water contamination was minimal; the content of oil hydrocarbons in the water after completion of work did not exceed 0.09 ± 0.04 mg L−1. This study demonstrates that flotation-based technology can be applied for in situ cleaning of oil-contaminated lake bottom sediments including those in boreal climates.

The paper describes a complex novel airlift plant for the simultaneous cleaning of water reservoir bottom sediments and water. The plant's design was tested in a model. Chemical analysis of the bottom sediments after experimental cleaning revealed a total oil content of 0.40–0.45 g kg−1, while the estimated initial oil content was around 16 g kg−1. This indicates a 35.5–40.0 times decrease in oil content.

The migration and accumulation of nickel (nNi) and platinum (nPt) nanoparticles (NPs) in loamy sand and loamy soils (Luvisols) occupying the largest area in the southeastern part of West Siberia, have been investigated. The experiments were made in situ. The loamy sand soils (Albic Lamellic Luvisol) were tested down to a depth of 55 cm to sorb 100% nNi and at least 71% nPt of their total introduced amount. The rest 29% nPt either penetrated below the depth of 55 cm, or moved laterally. The experimental results in loamy soils enormously differed. Thus, only 16 to 20% nPt and 8 to 10 % nPt migrated radially in the Albic Luvisol and adjacent Stagnic Luvisol, respectively, while the rest NPs shifted laterally. The differences between the loamy soils are associated with lesser biogenic porosity of the Stagnic Luvisol, and, as a consequence, with higher density. The NPs migration and sorption processes are related to the soil properties differentiation. The inverse correlation between the concentration of nPt sorbed in soil horizons and their density with R2 = 0.67 has been established. NPs have shown high migrational ability with nNi to a lesser extent, and nPt to a larger extent. During a single introduction, these are able to penetrate depths of more than 1 m with both gravitational and capillary water.

Aeolian sands and ancient dune fields are widely widespread in the southern part of Western Siberia. Aeolian landscapes formed in the bottom part of large ancient valleys, on the surfaces of modern fluvial terraces and near large lake systems are characterized by the unique soil cover which is determent by the sedimentalogical, mineralogical and granulometric properties of sands and very slightly dependent from local vegetation and climate. Soils of ancient inland dune landscapes located within the ancient valleys of Ob-Tom interfluve were investigated. It was shown that local topography is the main factor controlling the diversity of soils. Soils developed in dune topographical sequences differ from each other in the thickness of eluvial-illuvial horizons, content of humus and oxalate-extractable iron. Humus accumulation and podsolization process are rather poor because of the low ash content in the litter, intensive natural and anthropogenic dynamics of aeolian landscapes and adjacent soils. The fact that processes of lateral podsolization determine the processes of soil development in such landscapes has been established. All soils are characterized by a small thickness of the modern profile − 50 cm and even less for the flat surfaces of dunes. Clayey lamellaes typical for aeolian sediments are present in the bottom parts of soils profiles, located in the lower part of the dune-interdune sequence. It is rather obvious that thick cemented lamellaes are a powerful soil-geochemical barriers that largely determines the conditions for lateral and radial migration.