Speciation Of Forms Research Articles

Speciation distribution and leaching behavior of heavy metals in coal gasification fine ash: Influence of particle size, carbon content and mineral composition

In this study, the occurrence and distribution of heavy metals in coal gasification fine ash (CGFA) with different particle sizes were investigated to ensure safer disposal and utilization strategies for CGFA. These measures are critical to sustainable industrial practices. This study investigates the distribution and leachability of heavy metals in CGFA, analyzing how these factors vary with particle size, carbon content, and mineral composition. The results demonstrated that larger CGFA particles (>1 mm) encapsulated up to 70 % more heavy metals than smaller particles (<0.1 mm). Cr and Zn were present in higher concentrations in larger CGFA particles, whereas volatile elements such as Zn, Hg, Se, and Pb were found in relatively higher contents in finer CGFA particles. At least 70 % of Hg in CGFA was present in an acid-soluble form of speciation, whereas Cd, Zn, and Pb were mostly present in a reducible form of speciation, which could be attributed to the presence of franklinite. More than 40 % of Cd and Zn in fine CGFA particles exist in an acid-soluble form. With the exception of CGFA_1.18, Se in CGFA mainly existed in an oxidizable form at a ratio of 60 %–80 %. This could be attributed to the presence of bassanite particles as well as the higher affinity of Se for S. In contrast, Cr, Cu, and As were mostly present in residual speciation forms owing to their parasitism in quartz, sillimanite, and amorphous Fe solid solution in CGFA. Additionally, the study revealed that there was no significant relationship between heavy metal content, leaching behavior, and carbon content in CGFA. Based on combined analyses using toxicity characteristic leaching procedure (TCLP) leaching concentrations and risk assessment code (RAC) results, it is recommended to focus on the environmental risks posed by Cd, Cr, Pb, Zn, and Hg in CGFA during their modification and utilization processes.

Photo-Oxidation of α-Pinene Oxidation Products in Atmospheric Waters - pH- and Temperature-Dependent Kinetic Studies.

The atmospheric α-pinene oxidation leads to three carboxylic acids: norpinonic acid (NPA), pinic acid (PA), and 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA). In this study, the OH radical kinetics in the aqueous phase of these carboxylic acids were investigated at different temperatures and pH values of solutions. Activation parameters and the corresponding atmospheric lifetimes of the acids in the troposphere were derived. The overall second-order rate constants for the individual speciation forms of the acids (AH and A- for NPA; AH2, AH- and A2- for PA; and AH3, AH2-, AH2- and A3- for MBTCA) were determined. At 298 K, the rate constants for reactions of protonated forms (AHx) of NPA, PA, and MBTCA with •OH, were (1.5 ± 0.2) × 109 L mol-1 s-1, (2.4 ± 0.1) × 109 L mol-1 s-1, and (4.1 ± 0.6) × 108 L mol-1 s-1, respectively. For the fully deprotonated forms (Ax-) of studied acids, the second-order rate constants were (2.2 ± 0.2) × 109 L mol-1 s-1, (2.8 ± 0.1) × 109 L mol-1 s-1, and (10.2 ± 0.7) × 108 L mol-1 s-1 at 298 K, respectively. It was found that the reactions of NPA and PA with OH radicals are faster than with MBTCA. For MBTCA, the reaction rate depends on pH more strongly at elevated temperatures (>298 K). The atmospheric lifetimes of the acids considered due to their reactivity with •OH were calculated for different model scenarios at a temperature of 283 K and pH = 2 in the aqueous phase. For this purpose, liquid water content (LWC) was used for aerosols and clouds under storm conditions and at various aqueous-phase concentrations of OH radicals. The lifetimes decreased with increasing LWC (from 10-12 m3 m-3 in aerosol to 10-5 m3 m-3 in storms), indicating that the acids undergo significant aqueous processing under realistic atmospheric conditions. Besides, the aerosol systems appeared less effective in removing PA and NPA, with lifetimes ranging from hundreds of days to tens and hundreds of hours, respectively. Clouds were more effective, with lifetimes ranging from tens of hours to a single second or less. MBTCA, which dissolves better in water, was effectively removed in all systems, with the longest lifetime of approximately 90 min.

Exploring the aqueous photodegradation of three ionisable macrolide antibiotics: Kinetics, intermediates and photoinduced toxicity

Three macrolide antibiotics (MLs, i.e., roxithromycin, clarithromycin and spiramycin) were investigated to reveal the aqueous photochemistry of the respective neutral and dissociated species (i.e., H2MLs+, HMLs0 and MLs−), including their susceptibility to direct photolysis as well as the hydroxyl radical (•OH) and singlet oxygen (1O2) mediated photooxidation. Under simulated sunlight (λ > 290 nm), no obvious or slow photodegradation of the three MLs were observed in pure water, while they photodegraded rapidly under shorter wavelength irradiation (λ > 200 nm). It was further found that the dependence of the kinetics on pH was attributed to the different reactivities of the dissociation species. The rate constants and cumulative light absorption increased with the order H2MLs+ < HMLs0 < MLs−. Based on competition kinetic experiments and matrix calculations, MLs− was differentiated to be more highly reactive towards •OH/1O2. The corresponding environmental half-lives were evaluated considering the reactivities and proportions of the speciated forms at different pH, indicating that 1O2 oxidation (t1O2,E = 1.83–2.53 h) contributed more than •OH oxidation (t•OH,E = 33.17–787.49 h) to the ML phototransformation in sunlit surface waters. In general, these reactions preserved the core backbone structures of the parent ML molecules and gave rise to intermediates that displayed higher toxicity to Vibrio fischeri than the parent molecules, hence demonstrating photo-modified toxicity. These results are of importance towards the goal of assessing the persistence of MLs during wastewater treatment using UV-light tertiary treatment processes, as well as in sunlit surface waters.

Speciation of plutonium and some chemical elements in the bottom sediments of the Laptev sea and the Kara sea

The comparison of the speciation forms of 239Pu and chemical elements, including rare earth elements (REE), in the bottom sediments of the Kara Sea and the Laptev Sea is given. The speciation forms were investigated by three different methods of selective leaching. Data were obtained on the content of chemical elements and 239Pu in the composition of complexes with different lability: easily soluble, bound to organic matter, including groups of humic acids (HA) and fulvic acids (FC), as well as with amorphous oxides of Fe and Mn. It is shown that humic and low molecular weight organic acids and their compounds with chemical elements can influence the behavior of plutonium in the seawater-bottom sediments system in the waters of the Arctic seas. The possibility of using a number of REE as a marker for predicting the migration behavior of plutonium is evaluated.

An attempt to describe the correlation between granulometric structure and the concentration of speciated forms of phosphorus and selected metals in the bottom sediments of a thermally contaminated dam reservoir.

An attempt to describe the correlation between granulometric structure and the concentration of speciated forms of phosphorus and selected metals in the bottom sediments of a thermally contaminated dam reservoir.

Pollinator and habitat-mediated selection as potential contributors to ecological speciation in two closely related species.

In ecological speciation, incipient species diverge due to natural selection that is ecologically based. In flowering plants, different pollinators could mediate that selection (pollinator-mediated divergent selection) or other features of the environment that differ between habitats of 2 species could do so (environment-mediated divergent selection). Although these mechanisms are well understood, they have received little rigorous testing, as few studies of divergent selection across sites of closely related species include both floral traits that influence pollination and vegetative traits that influence survival. This study employed common gardens in sites of the 2 parental species and a hybrid site, each containing advanced generation hybrids along with the parental species, to test these forms of ecological speciation in plants of the genus Ipomopsis. A total of 3 vegetative traits (specific leaf area, leaf trichomes, and photosynthetic water-use efficiency) and 5 floral traits (corolla length and width, anther insertion, petal color, and nectar production) were analyzed for impacts on fitness components (survival to flowering and seeds per flower, respectively). These traits exhibited strong clines across the elevational gradient in the hybrid zone, with narrower clines in theory reflecting stronger selection or higher genetic variance. Plants with long corollas and inserted anthers had higher seeds per flower at the Ipomopsis tenuituba site, whereas selection favored the reverse condition at the Ipomopsis aggregata site, a signature of divergent selection. In contrast, no divergent selection due to variation in survival was detected on any vegetative trait. Selection within the hybrid zone most closely resembled selection within the I. aggregata site. Across traits, the strength of divergent selection was not significantly correlated with width of the cline, which was better predicted by evolvability (standardized genetic variance). These results support the role of pollinator-mediated divergent selection in ecological speciation and illustrate the importance of genetic variance in determining divergence across hybrid zones.

Rapid evolution of pre-zygotic reproductive barriers in allopatric populations.

Adaptive divergence leading to speciation is the major evolutionary process generating diversity in life forms. The most commonly observed form of speciation is allopatric speciation which requires that gene flow be prevented between populations by physical or temporal barriers, as they adapt to their respective environments. Eventually, these adaptive responses lead to accumulation of mutations in different lines. The increased genetic distance between the lines is known to lead to the populations becoming reproductively isolated. A widely accepted theory is that speciation simply occurs as a by-product of adaptive response of the populations. Several examples of allopatric speciation from ecology and laboratory exist. However, we know little about the nature (pre- or post-zygotic) of barriers that arise first in this process. Understanding the first barriers that arise between populations is key to understanding how the process of speciation initiates. In recent years, fungi have been used as model organisms to answer questions related to the evolution of reproductive isolation. Here, we show rapid evolution of pre-zygotic barriers between allopatric yeast populations. We further demonstrate that these pre-zygotic barriers arise due to altered mating kinetics of the evolved population. Moreover, our non-adaptive evolution experiments with yeast under limited selection pressure also show rapid emergence of reproductive isolation. Overall, our results show that evolution of pre-zygotic reproductive barriers can occur as a result of natural selection or drift.IMPORTANCEA population diversifies into two or more species-such a process is known as speciation. In sexually reproducing microorganisms, which barriers arise first-pre-mating or post-mating? In this work, we quantify the relative strengths of these barriers and demonstrate that pre-mating barriers arise first in allopatrically evolving populations of yeast, Saccharomyces cerevisiae. These defects arise because of the altered kinetics of mating of the participating groups. Thus, our work provides an understanding of how adaptive changes can lead to diversification among microbial populations.

The Content and Speciation of Radionuclides in Water and Bottom Sediments of the Laptev Sea

In the presented work, the features of the distribution of Cs-137 and plutonium isotopes in modern sediments of various parts of the Laptev Sea, selected during the expedition studies on the RV “Academician Mstislav Keldysh” in 2017 and 2019, were studied. It was found that the activity of Cs-137 in water and sediments is within the global level, which is typical for the seas of the Arctic region. In all the collected samples the specific content of Pu-239,240 isotopes is below the level of the minimum detectable activity. According to the results of isotope analysis of Pb-210, the sedimentation rates in two columns collected in the Laptev Sea are 0.18 and 0.23 cm/year. The study by several methods of the speciation forms of Pu-239, introduced into the samples of bottom sediments under laboratory conditions, showed that the main content of Pu-239 is associated with difficult-to-dissolve organo-mineral components. 30-39% Pu-239 was found in the composition of organic easily soluble acids and humic substances, which include fulvic and humic acids of bottom sediments.

On site separation of inorganic forms of thallium and arsenic in sea water systems followed by ICP-MS determination.

Reduction of Tl(III) and oxidation of As(III), which are unstable speciation forms, start just after sampling as a result of disturbed chemical equilibrium. Separation of inorganic Tl and As species, unchanged, is thus crucial for reliable results of speciation analysis in water systems. Presented here a simple and fast sample pretreatment, based on ion exchange cartridges, which gives the possibility to separate Tl and As species already on the sampling site. Note the reduction of Tl(III) (15%) is in the range of losses typical for standard procedures based on Tl(III) fixation. The use of SCX-3 allows for Tl(III) and SAX for As(III) separation, which are then quantitated in the effluent by ICP-MS. Determination of non-retained species was done after reduction of the sample volume to 2 mL (50-fold preconcentration), which allowed for detection of As concentrations <0.1 ppb and Tl <0.01 ppb. For As, a collision chamber is required. The possibility of direct determination is very important for the forms being in trace amounts in sea water in the vicinity of harbors.

Analysis of hydrochemical parameters and dissolved zinc interaction by using PHREEQC simulation

Zinc is frequently reacting with inorganic species in water to form zinc species. Thus, the chemical speciation of Zinc in the aquatic environment has become a significant concern nowadays due to its adverse effect on humans and its potential toxicity in the water system. In this study, to investigate the interaction between dissolved zinc and hydro-chemical factors and to estimate the Zn speciation form, samples of river water were collected spatially from the Umeda River mainstream and tributaries in different seasons for one year. The hydrochemistry and dissolved zinc pollution characteristics of the samples were analyzed. Zn speciation was assessed by PHREEQC simulation. The result show that the main form of Zn speciation was Zinc free ion (Zn2+) in all seasons. However, in summer and spring season, the ZnCO3 and ZnOH+ concentration was higher than the other season. These speciation form may be attributed to the activities around the river in different season according to the similarities in downstream and upstream areas by the hierarchical cluster analysis result.

Comparative Removal of Cr(VI) and F− Ions from Water by Freezing Technology

Trace element ions, such as Cr(VI) and F−, are of particular interest due to their environmental impact. Both ions exhibit an anionic nature in water that can show similar removal tendencies except for their significant differences in ionic radius, speciation forms, and kosmotropic-chaotropic behaviors. Accordingly, partial freezing was performed to examine the comparative freeze separation efficiencies of Cr(VI) and F– from aqueous solutions. Freeze desalination influencing parameters such as initial ion concentration, salt addition, and freeze duration were explored. Under optimal operating conditions, freeze separation efficiencies of 90 ± 0.12 to 95 ± 0.54% and 58 ± 0.23% to 60 ± 0.34% from 5 mg/L of Cr(VI) and F–, respectively, were demonstrated. The salt addition into the F–-containing solutions revealed more F– ion intercalation into the ice, initiating the decrement of freeze separation efficiency. The influences of structuring-destructuring (kosmotropicity-chaotropicity) and the size-exclusion nature of ice crystals were used to explain the plausible mechanism for the difference in freeze separation efficiency between Cr(VI) and F– ions.

Genome and cuticular hydrocarbon‐based species delimitation shed light on potential drivers of speciation in a Neotropical ant species complex

Geographic separation that leads to the evolution of reproductive isolation between populations generally is considered the most common form of speciation. However, speciation may also occur in the absence of geographic barriers due to phenotypic and genotypic factors such as chemical cue divergence, mating signal divergence, and mitonuclear conflict. Here, we performed an integrative study based on two genome‐wide techniques (3RAD and ultraconserved elements) coupled with cuticular hydrocarbon (CHC) and mitochondrial (mt) DNA sequence data, to assess the species limits within the Ectatomma ruidum species complex, a widespread and conspicuous group of Neotropical ants for which heteroplasmy (i.e., presence of multiple mtDNA variants in an individual) has been recently discovered in some populations from southeast Mexico. Our analyses indicate the existence of at least five distinct species in this complex: two widely distributed across the Neotropics, and three that are restricted to southeast Mexico and that apparently have high levels of heteroplasmy. We found that species boundaries in the complex did not coincide with geographic barriers. We therefore consider possible roles of alternative drivers that may have promoted the observed patterns of speciation, including mitonuclear incompatibility, CHC differentiation, and colony structure. Our study highlights the importance of simultaneously assessing different sources of evidence to disentangle the species limits of taxa with complicated evolutionary histories.

Aquatic bioaccessibility of tetracycline antibiotics to higher fauna: Prediction based on the water-column/sediment partition coefficient

Tetracycline drugs, extensively used as human and veterinary broad spectrum antibiotics, enter surface and drinking water sources through runoff and seepage following application of manure in agriculture, and direct discharge in pharmaceutical plant and hospital effluent. The aim of the present work was to study the bio-accessibility of tetracycline drugs in the aquatic environment to higher fauna. The study was achieved by first proposing an aquatic bio-accessibility coefficient towards higher fauna, defined as the fraction of the substance in solution in the water column over the mean concentration of the substance in a given aquatic system, and calculated assuming that non-settling adsorbed speciation forms are desorbed upon contact with the gastrointestinal fluid. The definition further assumes that organic substances residing within the sediment are not bioaccessible to higher fauna, but become bioaccessible following sediment-to-water-column equilibrium transfer. The bioaccessibility coefficients of tetracycline antibiotics in a typical tropical river ecosystem were studied by determining the distribution of the antibiotics between the water column and the sediment over a period of 90 days using microcosm experiments. Data are presented showing that, based on theoretical values calculated taking into account the different rates of degradation of different speciation forms of the antibiotic in both water and sediment phases of the aquatic ecosystem, oxytetracycline and chlortetracycline exhibit medium high aquatic bioaccessibility coefficients (1.0 – 1.5), while doxycycline exhibits a high aquatic bioaccessibility coefficient (1.5 – 2.0). The differences observed in the theoretical bio-accessibility coefficients of TCs are attributed to differences in the strengths of the adsorption bonds of different tetracyclines to colloidal particles. Data are further presented showing that experimental values of the aquatic bio-accessibility coefficient and water-clumn/sediment partition coefficient may also deviated considerably from their corresponding theoretical values, as a result of errors arising from re-suspension of antibiotic adsorbed to settling colloidal particles during sampling.

Calcium: A comprehensive review on quantification, interaction with milk proteins and implications for processing of dairy products.

Calcium (Ca) is a key micronutrient of high relevance for human nutrition that also influences the texture and taste of dairy products and their processability. In bovine milk, Ca is presented in several speciation forms, such as complexed with other milk components or free as ionic calcium while being distributed between colloidal and serum phases of milk. Partitioning of Ca between these phases is highly dynamic and influenced by factors, such as temperature, ionic strength, pH, and milk composition. Processing steps used during the manufacture of dairy products, such as preconditioning, concentration, acidification, salting, cooling, and heating, all contribute to modify Ca speciation and partition, thereby influencing product functionality, product yield, and fouling of equipment. This review aims to provide a comprehensive understanding of the influence of Ca partition on dairy products properties to support the development of kinetics models to reduce product losses and develop added-value products with improved functionality. To achieve this objective, approaches to separate milk phases, analytical approaches to determine Ca partition and speciation, the role of Ca on protein-protein interactions, and their influence on processing of dairy products are discussed.

Development of "Imprint-and-Report" Dynamic Combinatorial Libraries for Differential Sensing Applications.

Sensor arrays using synthetic receptors have found great utility in analyte detection, resulting from their ability to distinguish analytes based on differential signals via indicator displacement. However, synthesis and characterization of receptors for an array remain a bottleneck in the field. Receptor discovery has been streamlined using dynamic combinatorial libraries (DCLs), but the resulting receptors have primarily been utilized in isolation rather than as part of the entire library, with only a few examples that make use of the complexity of a library of receptors. Herein, we demonstrate a unique sensor array approach using "imprint-and-report" DCLs that obviates the need for receptor synthesis and isolation. This strategy leverages information stored in DCLs in the form of differential library speciation to provide a high-throughput method for both developing a sensor array and analyzing data for analyte differentiation. First, each DCL is templated with analyte to give an imprinted library, followed by in situ fluorescent indicator displacement analysis. We further demonstrate that the reverse strategy, imprinting with the fluorescent reporter followed by displacement with each analyte, provides a more sensitive method for differentiating analytes. We describe the development of this differential sensing system using the methylated Arg and Lys post-translational modifications (PTMs). Altogether, 19 combinations of 3-5 DCL data sets that discriminate all 7 PTMs were identified. Thus, a comparable sensor array workflow results in a larger payoff due to the immense information stored within multiple noncovalent networks.

Biogeographic Drivers of Evolutionary Radiations

Some lineages radiate spectacularly when colonizing a region, but others do not. Large radiations are often attributed to species’ adaptation into niches, or to other drivers, such as biogeography including dispersal ability and spatial structure of the landscape. Here we aim to disentangle the factors determining radiation size, by modeling simplified scenarios without the complexity of explicit niches. We build a spatially structured neutral model free from niches and incorporating a form of protracted speciation that accounts for gene flow between populations. We find that a wide range of radiation sizes are possible in this model depending on the combination of geographic isolation and species’ dispersal ability. At extremely low rates of dispersal between patches, each patch maintains its own endemic species. Intermediate dispersal rates foster larger radiations as they allow occasional movement between patches whilst sufficiently restricting gene flow to support further speciation in allopatry. As dispersal rates increase further, a critical point is reached at which demographically identical lineages may vary greatly in radiation size due to rare and stochastic dispersal events. At the critical point in dispersal frequency, some lineages remain a single species for a comparatively long time, whilst others with identical characteristics produce the largest radiations of all via a new mechanism for rapid radiation that we term a ‘radiation cascade’. Given a single species covering many patches connected with gene flow, a radiation cascade is triggered when stochastic dispersal is unusually low for a period, leading to an initial speciation event. This speciation means there are fewer individuals per species and thus further reduced gene flow between conspecifics. Reduced gene flow in turn makes it easier for further speciation to occur. During a radiation cascade, dispersal of individuals between patches continues at the same rate as before, but due to the increasing diversity it primarily introduces novel species that will later speciate, rather than adding to gene flow of existing species. Once a radiation cascade begins, it continues rapidly until it is arrested by a new equilibrium between speciation and extinction. We speculate that such radiation cascades may occur more generally and are not only present in neutral models. This process may help to explain rapid radiation, and the extreme radiation sizes of certain lineages with dispersing ancestors. Whilst niches no doubt play a role in community assembly, our findings lead us to question whether diversification and adaptation into niches is sometimes an effect of speciation and rapid radiation, rather than its cause.

Implication of biofilms in the sustainability of acid mine drainage and metal dispersion near coal tailings

In this study, the ecology of biofilms collected from sediments and efflorescent crusts (EFC) along an acid mine drainage (AMD) system was determined using 16S bacterial metagenomics. The dissolution of coal tailing and EFC by bacteria hosted in biofilms was investigated. Results revealed the predominance of acidophilic bacteria such as Acidithiobacillus ferrooxidans, Leptospirilum ferrooxidans, Acidithrix, Leptospirilum sp, Acidimicrobiaceae, Sulfobacillus, Acidiphilium, and Acidithiobacillus sp. in the biofilms, some of which have been reported to oxidize sulfide minerals and contribute to AMD formation. The experimental results further highlighted the ability of the bacteria in biofilms to leach out metals such as Co, Fe, and Zn, while decreasing the pH of the solution. The bioleaching of EFC was very fast, and increased diversity of the bacterial inoculum contributed to accelerating the leaching rate. Compared to abiotic leaching, the dissolution of minerals by acidophilic bacteria increased the percentage of free hydrated metal speciated forms over the inorganic complex speciated forms, suggesting the potential of biofilms to enhance the dispersion of metals in aquatic systems.

Analysis of Some Elements and Speciated Compounds in Fish Found in the New Calabar River of the Niger Delta Area, Nigeria

The flesh of guinean and blackchin tilapia, and mullet found in Choba river were collected for elemental studies of mercury, cadmium, lead, arsenic, nickel and speciated forms. Analytical method of X-ray fluorescence (XRF) was used for the elemental studies while Gas chromatographymass spectrometer (GC-MS) was used for the speciated forms. 4.3 mg/kg was the highest concentration of cadmium observed in blackchin tilapia. The three fish species all contained about 0.5 mg/kg of arsenic and 1 mg/kg of mercury. 1.7 mg/kg of lead was detected in mullet while 7.3 mg/kg of nickel was detected in blackchin tilapia. Organometallic compounds found were nickel tetracarbonyl, borane carbonyl in guinean tilapia, nickel tetracarbonyl, borane carbonyl and germanium(iv) pthalocyanine dichloride in blackchin tilapia and [µ-(ƞ6-benzene)] bis (ƞ5-2,4-cyclopentadien-yl) diµ-hydrodi-vanadium. Borane carbonyl was found in mullet.

Mobile forms of metal speciation under electrochemical action upon sulfide minerals

Mobile forms of metal speciation under electrochemical action upon sulfide minerals

Форми знаходження радіонуклідів у донних відкладеннях приміщення 012/7 об’єкта «Укриття»

After installation of the Arch of New Safe Confinement (NSC) into design position, precipitations intake in the underroof space of the Shelter object ceased, and water evaporation began from the unorganized accumulations of radioactively contaminated water. As a result of physical and chemical processes of coagulation and deposition of sparingly soluble salts, bottom sediments, containing uranium and radionuclides, formed. The aim of the work is to determine speciation forms of uranium and radionuclides in the bottom sediments, which formed due to the drying out of unorganized accumulations of radioactively contaminated water in room 012/7 of the NSC – Shelter object. Results of the experimental determination of speciation forms of uranium and radionuclides 90Sr, 137Cs, 154Eu, 238Pu, 239+240Pu, 241Am and 244Cm in the bottom sediments of room 012/7 of the NSC – Shelter object are presented. An amount of water-soluble, exchangeable and acid-soluble uranium forms, fission products and transuranium elements in the bottom sediments of room 012/7 of the NSC – Shelter object was determined by the method of consecutive extractions. Content of uranium, 90Sr, 238Pu, 239+240Pu, 241Am and 244Cm in the leaching solutions and insoluble residue was determined by the ion-exchange method. 90Sr activity was determined by beta-radiometric measurements. Activity of 234,235,236,238U, 238Pu, 239+240Pu, 241Am and 244Cm was determined by alpha-spectrometric measurements of uranium, plutonium and americium sources. The concentration of uranium in the bottom sediments of room 012/7 was 1.02 ± 0.26 mg/g. Abundance content of uranium isotopes is 234U – 0.0159, 235U – 1.09, 236U – 0.192 and 238U – 98.71%. Isotope content of uranium in the bottom sediments, on the whole, corresponds to the isotope content of uranium in the irradiated fuel of the Chornobyl NPP 4th unit with an average burnup. The specific activity of 90Sr and 137Cs in the bottom sediments of room 012/7 is in the range of 6∙108−1∙109 Bq/kg. 239+240Pu and 241Am specific activity in the bottom sediments is in the range of 6∙105 – 8∙106 Bq/kg. 90Sr, 137Cs, 154Eu, 238Pu, 239+240Pu, 241Am and 244Сm radionuclides in the bottom sediments are in different physical and chemical forms, which determine their potential mobility. Mainly uranium and 137Cs in the bottom sediments of room 012/7 are in the exchangeable forms. An amount of water-soluble forms of uranium and 137Cs is about 1.5 – 3%. The main amount of 90Sr, more than 60% is in the carbonate forms, which are very soluble in weak acid medium, when pH is 4.8. More than 65% of 238Pu and 239+240Pu in the bottom sediments of room 012/7 are in the acid-soluble forms. Potential mobility of 241Am in the bottom sediments is notably higher than of plutonium in the soluble state, when pH 4.8, transfer more than 40% of 241Am. Relations of activities of radionuclides 137Cs/90Sr, 90Sr/239+240Pu, 241Am/239+240Pu and 44Cm/239+240Pu in the bottom sediments of room 012/7 differ significantly from the similar relations in the fuel containing materials of the Shelter object.