Total Salt Content Research Articles

Diffusion of tritium, technetium, cesium, and uranium from phosphate glass leachates in pore solution of clay materials

The through diffusion method at room temperature was used to study the migration of radionuclides (3H, 99Tc, 137Cs, 233U) in compacted samples of clay materials during pore diffusion from a model leachate of the RW phosphate matrix with a total salt content of about 400 mg/L. Based on the results of the experiments, the effective diffusion coeffcients and coeffcients of the sorption distribution of radionuclides for the studied barrier clay materials were determined. Regularities of the diffusion transfer of tritium, cesium and uranium depending on the structure, mineral composition of clay materials and the content of radionuclides in the pore solution are revealed. Numerical modeles are proposed for calculating the effective pore di usion coeffcients of these radionuclides. There are still insuffcient data to analyze the factors affecting the diffusion of technetium.

Response of soil microbial community diversity to continuous cucumber cropping in facilities along the Yellow River irrigation area.

Cucumber is an important cash crop; however, continuous cropping obstacles readily occur within the intensive production processes of facility horticulture. This study aimed to determine the effects of continuous cropping on soil quality and the microbial community in the rhizosphere soil of cucumbers. Rhizosphere soil of cucumber planted continuously for 4, 8, and 12 years was investigated, and soil that was not continuously planted was used as the control. Soil physicochemical properties, enzyme activity, microbial diversity, and richness were determined. The results showed that with the increase in continuous cropping years (0, 4, 8, and 12 years), soil total salt content continuously increased, while the pH value significantly decreased. Compared with the control, soil organic matter, alkali-hydrolyzed nitrogen, available phosphorus, available potassium, and nitrate nitrogen contents increased significantly after 4 and 8 years of continuous cropping. Spearman correlation analysis showed that pH was negatively correlated with sucrase or sucrose and available phosphorus was positively correlated with alkaline phosphatase. Compared with the control, the diversity and abundance of bacterial and fungal communities in cucumber rhizosphere soil decreased after 4 and 12 years of continuous cropping. Continuous cropping led to a significant increase in the richness of the dominant phylum of cucumber rhizosphere soil. Principal coordinates analysis showed that, compared with the control, the soil microbial community structure was significantly separated after 4, 8, and 12 years of continuous cropping, and the microbial community structure was most similar after 4 and 8 years of continuous cropping. In addition, redundancy analysis showed that pH was the main driver of soil microbial dominance. In conclusion, continuous cropping of cucumber along the Yellow River irrigation area has led to the deterioration of soil nutrients and microbial communities in that region. This experiment provides a theoretical foundation for addressing the challenges associated with continuous cropping in cucumber cultivation.

Analysis of Water and Salt Spatio-Temporal Distribution along Irrigation Canals in Ningxia Yellow River Irrigation Area, China

The large amount of salinized soil in the Yellow River irrigation area is a threat to the sustainable development of agriculture, and in order to efficiently control the soil salinization trend, it is necessary to research water and salt variations and the distribution of soil in the area. In this study, soil salinization along two typical canals (West Main Canal and Tanglai Canal) in the Ningxia Yellow River irrigation area in China is investigated using data regarding water content, salt ions and pH from soil samples collected at 165 points along these canals. At each of these points, soil samples from various layers were collected for measurement from August 2019 to December 2020. Various methods, such as Pearson’s correlation analysis and Kriging interpolation, were employed to obtain the temporal and spatial distributions of water content, pH value and salt ions from the soil samples. It was found that the mean total salt value is 2.75 g/kg, which indicates that the soil in the study area is moderately salinized soil. The average value of soil pH is 8.5, indicating that the soil in this area is alkaline. Furthermore, it is evident that the coefficient of variation for certain soil ions, including HCO3−, Cl−, Ca2+, Na+ and K+, is greater than one, which indicates that their spatial distribution in the study area is severely uneven. Moreover, the soil salt content in the study area gradually increases from the southwest to the northeast, in the flow direction of the West Main Canal and the Tanglai Canal. The water content distribution along the two canals also exhibits notable non-uniformity, displaying a pattern higher in the north and east and less in the south and west. Moreover, the annual distribution of total salt content in the surface layer demonstrates an initial increase followed by a decrease, with the peak value typically occurring in August or September. The research results have an important significance on agriculture in the Ningxia Yellow River irrigation area.

Indirect Prediction of Salt Affected Soil Indicator Properties through Habitat Types of a Natural Saline Grassland Using Unmanned Aerial Vehicle Imagery

Salt meadows, protected within National Parks, cannot be directly surveyed, yet understanding their soil condition is crucial. Our study indirectly estimates soil parameters (Total Salt Content (TSC), Na, and pH) related to salinization/sodification/alkalinization using spectral indices and UAV survey-derived elevation model, focusing on continental lowland salt meadows. A vegetation map was created using 16 spectral indices and a Digital Elevation Model calculated from RGB orthophotos using photogrammetry. Field observations helped define habitat types based on the General National Habitat Classification System (Hungary), and quadrats with complete coverage of specific plant species were identified. Machine learning was employed on 84 training quadrats to develop a prediction algorithm for vegetation patterns. Five saline habitat types, representing variations in soil properties and topography, were identified. Spectral and topomorphometric indices derived from UAV were key to the spatial prediction of soil properties, employing random forest and co-kriging methods. TSC, Na, and pH data served as indicators of salt-affected soils (SAS), and thematic maps were generated for each indicator (57 samples). Overlapping with the vegetation map, the probability range of estimated SAS indicator values was determined. Consequently, a model-based estimation of soil pH, TSC, and Na conditions is provided for habitat types without disturbing protected areas.

Effects of the combined application of biochar and humic substances on the improvement of saline cropland in the Yellow River Delta of China

AbstractSoil salinization has become a global environmental problem with the potential to cause serious land degradation. Thus, improving salt‐affected soils and enhancing the nutrient utilization efficiency of saline farmlands through scientific and effective measures are urgent scientific problems. In this study, a 2‐year field experiment was conducted to evaluate the effects of different soil amendments and their combinations on the dynamics of soil salinity, soil nutrients, and crop yield in a moderately salinized soil (EC1:5 of 0.78 dS m−1 and total salt content of 3.06 g kg−1). Nine soil treatments were implemented: biochar (B), lignocellulose (L), humic acid (H), fulvic acid (F), biochar + humic acid (B + H), biochar + fulvic acid (B + F), lignocellulose + humic acid (L + H), lignocellulose + fulvic acid (L + F), and control (CK). The results demonstrated that the application of F led to a certain reduction on the contents of soil salt, Na+, and Cl− among the soils amended with a single amendment application. The combined application of B and F or H could increase the soil desalination rate and increase the mineral N and Olsen‐P concentrations at a soil depth of 0–20 cm, which improved the grain yield, biological yield, N recovery efficiency (REN), N agronomic efficiency (AEN), N partial factor productivity (PFPN), P agronomic efficiency (AEP), and P partial factor productivity (PFPP). Although the single application of L led to decreases in the grain yield, biological yield, REN, AEN, PFPN, REP, AEP, PFPP, and P physiological efficiency (PEP), the combined application of L and F had superior effects on enhancing the winter wheat grain yield and accumulative nutrient use efficiency. In conclusion, the combined application of B and F or H is recommended to ameliorate salt‐affected soils and improve nutrient availability.

A CASE STUDY ON THE POSSIBILITY OF SOIL MELIORATIVE STATE ASSESSMENT BY REMOTE SENSING DATA

The paper presents the results of the pilot study on the relationship between spatial bare-soil normalized difference vegetation index and content of salts in the dark-chestnut soil of the South of Ukraine. The study is based on the results of soil analyses, conducted in 2016 within the framework of sweet corn cultivation technology investigation at the Agricultural Cooperative Farm of Bilozersky district, Kherson oblast. The results of laboratory analyses were connected to bare-soil values of the spatial vegetation index, obtained at OneSoil platform. The relationship was estimated through rank correlation and polynomial regression analysis. As a result, very strong relationship was established between bare-soil vegetation index and toxic salts content in the soil, while moderate inter-connection was found out between the index and total salts content in the soil. The second-grade polynomial models, developed in the intercourse of regression analysis, proved to have very good fitting quality and accuracy of the salts content prediction, with the mean absolute percentage error 2.93-4.27%. Thus, bare-soil normalized difference vegetation index is suitable and prospective for meliorative surveys of the dark-chestnut soils of the South of Ukraine.

Soil salinity estimation in Shule River Basin using support vector regression model

AbstractSoil salinization is a progressive degradation process that spreads globally and leads to a decline in soil fertility. Assessing the scale of salinization is crucial for sustainable agricultural development and saline‐land rehabilitation. In this study, we proposed a support vector regression spatial (SVR‐S) model that utilizes spatial dependence information to predict soil salinity over the irrigation area of the Shule River Basin in northwestern China. To investigate the performance of the SVR‐S model, 50 soil samples were collected in the field. Semivariograms of soil salinity (measured as total salt content and ion concentrations) were constructed to measure spatial dependence. The SVR‐S model was compared with the original SVR model and the geographically weighted regression (GWR) model regarding the salinity prediction ability. The soil salinity in the experimental area demonstrated a strong spatial dependence pattern. The SVR‐S model delivered a better performance than the SVR‐O and GWR. SVR‐S showed a correlation coefficient R of 0.87 and a root mean square error (RMSE) of 1.83%, while the performance of SVR‐O (R = 0.75, RMSE = 3.32%) and GWR (R = 0.73, RMSE = 3.47%) was comparatively poor. Topographic indices integrating spatial information contributed the most to the estimation of salinity in the study area. This study provides a new approach to integrating spatial information for accurate soil salinity mapping.

Size and Composition Control of Magnetic Nanoparticles

Magnetite nanoparticles are a type of magnetic nanoparticle (MNP) that are inexpensive to make and can be formed in different shapes and sizes. MNPs can be used in DNA/RNA purification, drug delivery, and other biomedical applications. The commonly employed solvothermal route to make these MNPs gives the most uniform products with the smallest size distribution, but there is a need to identify easily controlled changes to reaction parameters that can reliably tune the size and composition of the MNPs made by this method. In this work we report simple and reliable methods whereby adjusting the total water content and basic salt concentration affords size and composition control, respectively. We employ synchrotron X-ray absorption measurements to prove our method offers monotonic control over MNP composition from maghemite-rich (γ-Fe2O3) to the more magnetic magnetite (Fe3O4). This demonstrates a simple, general method to produce particles with high magnetite concentration and the desired size.

Chemical characteristics and reactive transport of soil salt ions in frozen soil during the freeze and thaw period

Current researches on estimating soil salt movement during the freeze and thaw period are mainly based on total salt concentration, while ignoring the phase change of multi-component salts. In this study, the potential transport capability of soil water and salt ions in the frozen layer was investigated based on chemical characteristics and solute convection–diffusion theory. Field experiments were implemented to measure the change of total soil water, soil salt and its ion components. The soil water and salt content in liquid and solid phases were calculated by the FREZCHEM model, and then the movement of liquid soil water and soluble salt were simulated by the HYDRUS-1D model. The potential migration capability of soil water and salt components were then estimated by comparing the distribution profiles obtained by HYDRUS-1D and FREZCHEM. The results show that more than 74.5% of Cl, Na and SO4 were in liquid phase, which were less affected by precipitation-dissolution reaction and owned strong mitigation. The liquid soil water, soluble salt and salt ions in the frozen layer tended to decrease at the beginning of the freeze period and increase significantly at the end. The migration direction and quantity of various salt ions were different due to their concentration gradient and diffusion coefficient, causing the larger potential convection and dispersion quantity of Na+, Cl− and SO42- than those of Ca2+, Mg2+ and HCO3–. This study provides a new perspective for soil salt movement in frozen soil in agricultural areas with shallow groundwater table depth.

Coupled modelling of artificial freezing along clay-sand interface under seepage flow conditions

The artificial freezing in the clay-sand stratum under seepage flow conditions involves the hydro-ice-salt-crystalline-thermal-mechanical coupling process. A theoretical model is derived to investigate the influences of water seepage on the freezing process in the clay-sand stratum. The good agreements between the results from the theoretical model and laboratory tests in the literature verified the accuracy of the proposed model. Parametric studies are conducted to investigate the influences of the seepage velocities and temperature gradients on the spatial distributions. It is found that the ice contents, crystalline salt contents and adsorbed salt contents distribution profiles in the clay-sand stratum are nonlinearly distributed with a cliff distribution curve existing on their interface. The crystalline salt contents in the clay layer are higher than those in the sand layer due to the influence of water seepage and heat transfer. The adsorbed salt contents in the frozen area account for 2% of the total salt contents, but those in the unfrozen area account for 8% of the total salt contents. Due to the volume expansion caused by the soil skeleton deformation, thickness of fractional ice, ice frost heave deformation and salt swelling deformation, the soil deformation distribution curves in the clay-sand stratum are in a bilinear shape.

Impact of Salinity and Sodicity on Crop Growth and Physicochemical Properties of Some Aridisol and Vertisol Soils in Sudan: A Review

Comprehensive field and laboratory studies were undertaken toinvestigate the performance of some crops on salt-affected soils in Sudan.To separate salinity and sodicity indicators some laboratory studies wereconducted on soils equilibrated with mixed NaCl-CaCl 2 solutions. Therelative hydraulic conductivity (RHC) or diffusivity increased withincrease in total salt concentration (C) and decrease in exchangeablesodium percentage (ESP). A dispersion index (DI), a swelling index (SI),shrinkage volume and modulus of rupture increased with increase in ESPand decrease in C. The data showed a highly significant linear decrease inRHC with increase in DI or SI. The threshold salt concentrations (THC),which gave 75% of the highest RHC, and ESP relationships, wereobtained for samples from an Aridisol and a Vertisol soils.. The salinityprofile obtained after intermittent leaching with water suggested thepresence of a desalinized zone followed by a salinized one with thehighest salt concentration below the wetting front. The depth of thedesalinized zone increased significantly with increase of the amount ofwater stored (r2 = 0.968) and the length of the wetting front (r2 = 0.974).Soil amendments promoted salt leaching in the following order: Sand>chicken manure> water hyacinth> gypsum> dry sewage> farm yardmanure> control. Cumulative evaporation (E) for the various amendments

Spatial heterogeneity of soil properties of recreational areas of Volgograd

The article presents the developed soil maps and maps of spatial variability of soil properties (pH, total salt and carbonate content, organic carbon, density) in some recreational areas of Volgograd. The anthropogenic soils in the studied recreational areas include various urbostratozems (Urbic Technosols (Transportic)), Ekranic Technosols (Transportic), as well as quasizems (Phaeozems (Tehnic)), among the agrogenic ones – accumulation-carbonate agrozems (Cambisols (Aric, Protocalcic). Natural soils are represented by light and dark humus soils, chestnut soils, solonetz, as well as stratozems and psammozems. According to the data of isolinear mapping, it was found that acid-alkaline properties of soils of green zones vary from slightly alkaline to alkaline depending on the soil horizon and anthropogenic load. The mapping did not reveal salinization of the upper 0–30 cm layer. Values of organic carbon vary greatly (1–10%) and are conditioned by the presence or absence of meliorative artificial layers, as well as by the character of territory use. The content of calcium carbonates in the upper 30 cm is small and varies from 0.7 to 5%. It is established that the physical properties (density) directly depend on the level of anthropogenic load, increasing in footpaths and lawns. Spatial assessment of the properties of urban soils is important for identifying areas with an excess or on the contrary – low content of certain chemical and physical indicators for the planning of landscaping and gardening of urban areas.

Physicochemical properties and risk assessment of perishable waste primary products

Fertilization has become one of the most important ways to recycle perishable waste. In order to reveal the effect of the nutrient of the perishable waste primary products on the market and the possible impact of their application, 136 perishable waste primary products were sampled in nine cities in Zhejiang province, China. The result shows that these products have high nutrient content (average nutrient content was 5.00%). However, the conductivity (7.19 mS/cm) total soluble salt content (12.07%), and grease content (5.99%) were too high. The excessive salt and grease may cause harm to soil and crops, and become the main limiting factors for the fertilizer utilization of perishable waste. Heavy metal content of most of the samples met current commercial organic fertilizer standards, except that lead and chromium content of some samples exceeded the limit standard. Toluene, ethylbenzene, m & p-xylene were generally detected in the samples. These toxic and harmful substances have brought risks to the safe use of perishable waste into fertilizers.

Simplistic determination of the membrane pore charge density in presence of mixture of electrolytes

Membrane pore charge density (Xd) is an effective but non-measurable parameter for determining the performance of low cut-off ultrafiltration (LCUF) and nanofiltration (NF) membranes. Xd along with the physicochemical properties of the solution determines the membrane zeta potential. These properties include the solution pH, ionic strength as well as the ratio and nature of electrolytes in the solution. Hence, with the prior knowledge of the solution physicochemical properties and the zeta potential, determination of Xd is possible. In this study, the effect of binary mixture of electrolytes, i.e., NaCl/Na2SO4 on the membrane zeta potential was investigated for different solution pH (3–9) as well as the total salt concentration (2–10 g L−1). An empirical correlation between Xd and the other experimentally measurable parameters was developed. Salt rejection experiments were carried out with the above mentioned combinations of pH and total salt concentration along with different weight ratios of NaCl/Na2SO4 namely, 100:0, 90:10, 70:30, 50:50 and 0:100 for six LCUF membranes. For PAN PDA/PEI 12 membrane, at pH 7 and 2 g L−1 of total salt concentration, the rejection of divalent anion (SO42−) was increased from 60% to 75.3%, for monovalent cation (Na+), it was increased from 33% to 41.2% with the concentration of Na2SO4. However, the corresponding rejection of monovalent anion (Cl−) was decreased from 33% to 16.1%. For each of the experimental condition, Xd obtained from the Donnan Steric Pore Model (DSPM) solution was correlated with the zeta potential (ζ) and weight fraction of divalent salt (r) as: Xd=a+br+cζ. The effect of the solution pH and ionic strength is included in the membrane zeta potential. The correlation was successfully tested for the commercial membranes in predictive mode. The empirical correlation proposed in this paper acts as a useful tool to determine Xd for amine based LCUF membranes. This helps to predict the membrane performance for real life desalination treatment without performing a series of rejection experiments.

Physicochemical Properties, Amino Acid Composition and Volatile Components of Fermented Fish (Pla-ra) Accelerated by Starter Cultures

Fermented striped snake-head fish, known as Pla-ra, is a popular traditional food that is eaten throughout Thailand. Lactic acid bacteria (LAB) are found as the dominant microorganisms in many fermented fish products. The primary role of LAB is to ferment the available carbohydrates, and thereby causes a decrease in pH. The combination of low pH and organic acids (mainly lactic acid) are the main preservative factors found in fermented fish products. The purpose of this study was to determine the change in physicochemical properties, amino acid composition, and active volatile compounds of Pla-ra, by adding halophilic bacteria and LAB into the fish fermentation. The results revealed that the pH of the 8 Pla-ra treatments were found between 5.33 - 5.63, and the salt content of all Pla-ra treatments, ranged from 20.60 to 22.28 %. The increase in total acidity and the degree of hydrolysis (DH), is generally accompanied by a decrease in pH. The FMP treatment had the highest total acidity, protein, salt, DH and amino acid contents, but had the lowest pH. The important amino acids in all 8 Pla-ra treatments were glutamic acid, lysine, and leucine. There were 43 volatile compounds detected in Pla-ra, and the 7 prime ones were aldehyde, alcohol, ester, furan, pyrazine, sulfur, and ketone. Micrococcus sp., Bacillus subtilis and Pediococcus halophilus strains, and roasted rice powder were added to the fish fermentation, which greatly enhanced the flavour and volatile compounds in Pla-ra. HIGHLIGHTS Halophilic bacteria and lactic acid bacteria (LAB) added into the striped snake-head fish or Pla-Chon fermentation were greatly enhanced the flavour and volatile compounds in Pla-ra Striped snake-head fish fermentation can be accelerated by the addition of halophilic bacteria and LAB, and roasted rice powder 9 Non-essential amino acids and 9 essential amino acids were detected in Pla-ra Dominant amino acids in all 8 Pla-ra treatments were glutamic acid, lysine, and leucine 43 Volatile compounds were detected in Pla-ra with aldehyde, alcohol, ester, furan, pyrazine, sulfur, and ketone were the 7 prime ones GRAPHICAL ABSTRACT

Feature and mechanism analysis of dispersive soil disintegration impacted by soil water content, density, and salinity

AbstractDispersive soil has caused innumerable water‐induced erosion failures of earthen structures in arid regions up to now, among which disintegration, as the first response process, is commonly deemed as the primary inducement but with inadequate understanding. In this study, the disintegration characteristics of a compacted dispersive lean clay with sand were investigated by carrying out laboratory disintegration tests under a water immersion regime. Soil mass water content (ω), dry density (ρd) and total soluble salt content (η) were considered. Results suggest that for dispersive soil, (1) the disintegration process exhibited two distinct modes, which was divided by the ω near the optimum water content; (2) higher ρd delayed disintegration monotonously; (3) increasing η first weakened and then enhanced the disintegration, in which pattern the η at the inflection point increased with increasing ρd, showing a density dependence. Evolutions of representative soil morphology were illustrated. More importantly, the underlying influential mechanism of ω and η to disintegration were elaborated emphatically: (1) the initial clay dispersion level, soil consistency change, and conceptual “constraint force” exerted by soil matric suction jointly determine the disintegration modes; (2) increasing η makes the soil pore solution concentration higher and microstructure simpler, competition between the two leads to nonmonotonic change patterns of disintegration completion time (Td) and defined velocity (Vd); the interactive effect of ρd and η manifests that η produces an additional influence on the base of microstructure created by ρd. Finally, the grey relation entropy analysis was introduced to evaluate the contributions of the three test variables to Td and Vd. The obtained results and proposed perspectives are expected to be conducive to a deeper comprehension of the same or relevant behaviours of dispersive soils in the presence of water, so as to provide new insights for the targeted prevention and control of dispersive soil catastrophes.Highlights Disintegration of dispersive soil shows two distinct water content‐dependent modes. Soil salinity has a two phase impact on disintegration of dispersive soil. Dry density and soil salinity interact affecting disintegration. Relationship between soil dispersion and disintegration is elaborated.

Reinforced soil salinization with distance along the river: A case study of the Yellow River Basin

Clarifying the relationship between salt-affected soils and their adjacent river systems is critical to address the challenges posed by soil salinization on agricultural production. Among the various biophysical and land management factors linked to soil salinization, few studies have investigated the importance of the distance along the river. Based on the Hetao Irrigation District of the Yellow River Basin, we collected 5314 soil samples and analyzed 17 soil parameters to explore the relationship between salt-affected soils and their distance along the river. Soil salinization was reinforced by the distance along the river, as a trade-off between soil ion accumulation and nutrient regulation. Soil total water-soluble salt content increased by 16.4 mg kg−1 every kilometer, likely due to ions leaching from the soils upstream and partially accumulating in the soils downstream, especially for Cl-, SO42-, and Na+. Greater input and less solubility of Ca2+ based soil amendments, phosphorus fertilizers, and organic materials on the less salt-affected soils upstream may explain the declines in soil Ca2+, available phosphorus, and soil organic matter with distance along the river. With every kilometer along the river, soil exchangeable sodium and cation exchange capacity increased by 8.89 × 10−4 and 1.26 × 10−2 cmol kg−1, respectively, which led to an increase in soil exchangeable sodium percentage by 9.59 × 10−5. The increase in soil exchangeable sodium along the river was mainly due to Na+ accumulation, while soil cation exchange capacity was regulated by soil organic matter and total nitrogen. Soil pH increased by 1.21 × 10−3 per kilometer along the river, associated with the decrease of soil organic matter. Future saline soil amelioration and reutilization initiatives at regional scales may be improved by accounting for the changes in soil physicochemical properties resulting from the distance along the river.

Synthesis, optimization, and cell response investigations of natural-based, thermoresponsive, injectable hydrogel: An attitude for 3D hepatocyte encapsulation and cell therapy.

For the purpose of developing a 3D vehicle for the delivery of hepatocytes in cell therapy, the improved system of crosslinker and new gelling agent combinations consisting of glycerophosphate and sodium hydrogen carbonate have been employed to produce injectable, thermoresponsive hydrogels based on chitosan and silk fibroin. Adjusting the polymer-to-gelling agent ratio and utilizing a chemical crosslinker developed hydrogel scaffolds with optimal gelling time and pH. Applying sodium hydrogen carbonate neutralizes chitosan while keeping its thermoresponsive characteristics and decreases glycerophosphate from 60% to 30%. Genipin boosts the mechanical properties of hydrogel without affecting the gel time. Due to their stable microstructure and lower amine availability, genipin-containing materials have a low swelling ratio, around six compared to eight for those without genipin. Hydrogels that are crosslinked degrade about half as fast as those that are not. The slowerr degradation of Silk fibroin compared to chitosan makes it an efficient degradation inhibitor in silk-containing formulations. All of the optimized samples showed less than 5% hemolytic activity, indicating that they lacked hemolytic characteristics. The acceptable cell viability in crosslinked hydrogels ranges from 72% to 91% due to the decreasing total salt concentration, which protects cells from hyperosmolality. The pH of hydrogels and their interstitial pores kept most encapsulated cells alive and functioning for 24h. Urea levels are higher in the encapsulation condition compared to HepG2 cultivated alone, and this may be due to cell-matrix interactions that boost liver-specific activity. Urea synthesis in genipin crosslinked hydrogels increased dramatically from day 1 (about 4mgdl-1) to day 3 (approximately 6mgdl-1), suggesting the enormous potential of these hydrogels for cell milieu preparation. All mentioned findings represent that the optimized system may be a promising candidate for liver regeneration.

Characteristics of irrigated soils of Bukhara region intended for cotton sowing

The work is devoted to the study of the characteristics of irrigated soils of the Zhondarsky district of the Bukhara region, intended for sowing cotton. The acreage allocated for the cultivation of agricultural crops should have appropriate indicators that ensure not only high yields, but also high-quality products. Since many soils of the territory of Uzbekistan, including the Bukhara oasis, are highly saline, research work was carried out on the territory. Along with the other twelve regions, the irrigated soils of the Bukhara region are moderately saline, although there are some farms in which the land is characterized by a high degree of salinity. Among the districts and cities with a high level of salinity, as an example, we can take the soils of the Karakul and Olot districts of the Bukhara oasis. Due to the fact that these areas are located in the desert zone of the region, the salinity level is high due to the low amount of precipitation. The indicators of the content of biogenic elements and the mineral composition of the studied soil samples, the total salt content in the composition of soil samples were studied. The content of soluble ions, the content and studies of the main elements that ensure soil fertility such as humus, phosphorus, nitrogen, potassium and their mobile forms, as well as concentrations of soluble salts in the form of anions, cations and macronutrients have shown that the studied soil belongs to the depleted type of sulfate-chloride salinization.

Factors leading to high concentrations of pollutants in surface waters

The dependence of the frequency of excess of hygienic standards in surface waters on individual substances and complex indexes is investigated. It was found that in some cases, there are significant dependencies on production-induced factors (water withdrawal, wastewater discharge, percentage of plowed lands), while in other cases natural factors (climatic humidity, geological structure of catchment areas) are the predominant ones. Technogenic factors are predominate in case of high values of biochemical oxygen consumption, concentrations of petroleum products and nitrogen compounds. Natural factors of high concentrations are more significant for metal ions, chlorides, sulphates and total salt concentrations. With regard to metals, especially copper and zinc, very strict standards have been adopted in Russia, which also contributes to a very high repeatability and multiplicity of their excess. As for phenols and chemical oxygen consumption, the role of natural or man-made factors is less unequivocal.