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.

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To better understand freezing -thawing cycles operating in peat soils of permafrost landscapes, we experimentally modelled bi-directional freezing and thawing of the three sections of 90-cm long peat core collected from a discontinuous permafrost zone in western Siberia. We measured translocation of microorganisms and changes in porewater chemistry (pH, UV absorbance, dissolved organic carbon (DOC), and major and trace element concentrations) after thawing and two-way freezing of peat cores. We demonstrate that bi-directional freezing and thawing of a peat core is capable of strongly modifying the vertical pattern of bacteria, DOC, nutrients, and trace element concentrations. Sizeable enrichment (a factor of 2 to 5) of DOC, macro-(P, K, Ca) and micro-nutrients (Ni, Mn, Co, Rb, B) and some low-mobile trace elements in several horizons of ice and peat porewater after freeze/thaw experiment may stem from physical disintegration of peat particles, leaching of peat constituents and opening of isolated (nonconnected) pores during freezing front migration. However, due to the appearance of multiple maxima of element concentration after a freeze-thaw event, the use of peat ice chemical composition as environmental archive for paleo-reconstructions is unwarranted.

Our earlier studies showed that paired photostimulation allows the detection of pollutants in an aqueous medium according to the behavioral responses of freshwater Crustacea. The first stimulus initiated and stabilized the behavioral response. The increase in response to the second stimulus made it possible to assess the responsiveness of the zooplankton community. This paper studies the validity of this method for the detection of micro- and nanoplastic contamination of saltwater reservoirs according to the behavioral response of Artemia salina and Moina salina crustaceans. The studies were conducted in laboratory conditions using a submersible holographic camera developed by us, which ensures the in situ detection of the concentration and speed of crustaceans in a volume of up to 1 dm3, as well as makes it possible to change the intensity and duration of the attracting light. It was established that the phototropic response of crustaceans decreases in seawater at the cumulative dose of exposure to microplastics—0.15 mg∙dm−3∙h and nanoplastics—0.3 mg∙dm−3∙h. The paired photostimulation reveals the altering effect of micro- and nanoplastics in the saltwater medium no later than 3 h after their appearance, which indicates the promising potential of this method for the alarm response in monitoring the environmental well-being of water bodies.

The paper is devoted to studying the stability of of dispersed systems (DS) of nanoparticles (NP) of nickel (nNi), platinum (nPt), titanium dioxide (nTiO2), zinc oxide, multicomponent nanopowder (MNP) and multi-walled carbon nanotubes (MWCNT), formed basing on the growth media used in bioassay with application of aquatics: bacterial test-cultures Ecolum, Photobacterium phosphoreum and Escherihia coli, unicellular algae Chlorella vulgaris Beijer, infusoria Paramecium caudatum, cladocera Daphnia magna Straus and Ceriodaphnia affinis, fish Danio rerio. In the process of establishing a test-system the increase in the initial nanosubstance concentration of more than 5 mg/l results in the increase in the speed of aggregation of NP into DS and the decrease in their final concentration. We suggest the variants of estimation of effective concentration of NP in long-term biotesting.

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