Average Mineralization Research Articles

Hydrochemical characteristics of water quality of the Bystrytsia River basin (Lviv region)

The article investigates the hydrochemical composition of water in the Bystrytsia River basin. The ratio of the main water ions was determined and it was found that along the flow the hydrochemical facies of water changes from HCO3-–Ca2+ to HCO3-–Ca2+–Mg2+. River water has an average mineralization, which increases from 391 mg/l to 463 mg/l. The reaction of the environment in the Bystrytsia River basin is mostly slightly alkaline (pH=8.15) and changes to neutral (pH=7.2) in the village of Hrushiv. Permanganate oxidation of river water in the village of Velyka Ozymyna is higher than in other areas and is associated with the presence of lowland peatlands in this area, which are a source of humic acids. A tendency for a gradual increase in phosphates P–PO43- from the river source to its mouth and sudden changes in the concentration of nitrates N–NO3- has been noted. The contamination coefficients of such biogenic elements are less than 1. Ammonium ions, nitrites and many heavy metals (Zn, Mn, Cu, Co, Ni, Pb) were not detected in the river water of the Bystrytsіa river basin. The water in the Bystrytsia River basin corresponds to class 1 according to the water pollution index (very clean, IW=0.02-0.16) and this indicator is 1.8 times lower than in the Dniester River. The increase in the water pollution index along the river is due to increases in the multiplicity of phosphates in the water. The ecological state of water in the Bystrytsia River basin using the complex indicator СPES was determined to be stable with features of instability (CPESmin=-0.61 and CPESav=0.87), instability was detected in the Novoshytska HPP reservoir, in the villages of Zalokot and Urizh. The negative complex indicator of the ecological state of water in these areas corresponds to the sanitary and toxicological indicators (CPES 3) and is due to the influence of magnesium ions, which dominate over Ca2+ ions in river water, form the HCO3- – Mg2+ or HCO3- – Mg2+ – Ca2+ hydrochemical facies and exceed the permissible content. A stable water state with features of instability has been established in the Dniester and Cherkhavka rivers. According to the IZV, the waters are very clean, but have increased mineralization (>500 mg/l), higher hardness (5.8 and 4.7 mmol-eq/l), stronger acidity (pH=7.2 especially in the Dniester), higher permanganate oxidation (4.2 mg O/l mostly in the Dniester), higher concentration of Fe3+ ions (4.9 μg/ml mostly in the Dniester). The hydrochemical composition of the water is different: HCO3- – Ca2+ – Mg2+ in the Dniester and Ca2+– HCO3- – Na+ in the Cherkhavka. These analytical results would be useful for building a hydrological conceptual model that ensures better use of the natural water system in the Bystrytsia River basin. Key words: Bystrytsia River basin; main ions; biogenic components; chemical oxygen demand; water pollution index; water quality assessment by a complex indicator.

The Impact of Soil Dry–Wet Cycles on the Mineralization of Soil Organic Carbon and Total Nitrogen in Check Dams of the Loess Plateau

Frequent soil drying and wetting cycles significantly affect the mineralization processes of soil organic carbon (SOC) and total nitrogen (STN), impacting soil quality and contributing to nutrient loss. However, the effects of these dry–wet cycles on SOC and STN mineralization in dam soil are not well understood. This study simulated four consecutive wet–dry cycles under five soil moisture gradients of 0% (CK), 5%, 10%, 15%, and 100%, and 100%, across four cycles of 7, 14, 21, and 28 days, to investigate the effects on soil aggregates, enzyme activities, and the mineralization of SOC and STN. The results indicated that soil enzyme activity peaked after two dry–wet cycles and then began to decline. The dry–wet cycles reduced the proportion of soil macro-aggregates while also decreasing the proportions of small and micro-aggregates. In contrast, the 100% treatment conditions exhibited the opposite effect. Dry–wet cycles enhanced the mineralization rates of SOC and STN, with the average mineralization rates under the 10% soil moisture content being the highest—1.78 and 2.38 times greater than the CK treatment for SOC and STN, respectively. The impact of dry–wet cycles on SOC and STN mineralization through the enzyme pathway was greater than through the aggregate pathway. These research findings provide theoretical insights and scientific references for the efficient operation and ecological protection of sedimentation dams in the Loess Plateau.

Characteristics of Soil Respiration and Organic Carbon Mineralization in Dryland Potato Fields Under Different Ridge-furrow Mulching Patterns

Exploring the response mechanism of soil respiration rate to hydrothermal factors and organic carbon mineralization under different ridge-furrow mulching modes is of high importance for the development of the regional carbon cycle and assessment of its ecological benefits. An experimental study was carried out in 2020 in a dry-crop potato field in the mountainous area of southern Ningxia by setting three furrow-ridge ratios [60 cm∶30 cm （R1）, 60 cm∶45 cm （R2）, and 60 cm∶60 cm （R3）] combined with three mulching modes [ridge covered with ordinary plastic film, furrow covered with straw （DJ）, degradable water-permeable plastic film （DS）, and no mulching （DB） in furrows, respectively]. The soil hydrothermal factors, respiration rate, organic carbon content, and mineralization characteristics of potatoes during the reproductive period under different mulching modes were investigated with plain mulching without mulching （CK） as the control. The results showed that different furrow-ridge ratios combined with the mulching mode could significantly increase the soil water storage capacity in the 0-60 cm layer, and the R3DJ treatment had a better effect, with a significant increase of 24.99% compared with that in CK. The R2 treatment had the best effect of increasing temperature during the whole life cycle of the potato. The DS treatment had the effect of increasing temperature, and the DJ treatment had the effect of decreasing temperature under different mulching materials. Different furrow and ridge cover patterns could significantly increase the average soil respiration rate during the reproductive period, and the R3DS treatment was the most significant among the different furrow and ridge cover patterns, with a significant increase of 24.71% compared with that in the CK treatment. The soil organic carbon content in the 0-20 cm and 20-40 cm layers at harvest time was higher in the R2 and R1 ridges, respectively, and higher in the DB and DS treatments for different mulching materials. The soil organic carbon mineralization rate declined rapidly in the early stage of cultivation and then slowly declined and leveled off in the middle and late stages, which was highest in the R3 treatment for the three types of ridge ratios and highest in the DS treatment for different mulching materials. The fitting equations of soil respiration rate with soil hydrothermal factors during the reproductive period revealed that the synergistic effect of soil hydrothermal dual factors on soil respiration was higher than that of a soil hydrothermal single factor and that the quadratic hydrothermal dual factors could well explain 86.4% to 99.9% of the soil respiration. Correlation analysis showed that the average soil respiration rate during the whole life span of the potato was highly significantly and positively correlated with the average soil temperature in the 0-25 cm layer and the average soil organic carbon mineralization rate in the 0-40 cm layer, and the soil temperature was highly significantly and positively correlated with the organic carbon mineralization rate. The furrow-ridge ratio combined with the mulching mode was shown to improve the soil hydrothermal environment and increase the rate of organic carbon mineralization, thus affecting the soil respiration rate, with a furrow-ridge ratio of 60 cm∶45 cm or 60 cm∶60 cm under the ridge mulching mulch ditch covering biodegradable seepage mulch mode being more effective.

Внутригодовая динамика химического состава воды в устье реки Баксан

The article presents the results of a study of the intra-annual dynamics of the chemical composition of water at the mouth of the Baksan River in 2023. The intra-annual dynamics of transparency, pH, mineralization, hardness, permanganate oxidizability, content of macrocomponents (bicarbonates, chlorides, sulfates, nitrites, nitrates) and iron compounds were studied. According to average annual values, the water of the studied object has average hardness and belongs to the hydrocarbonate, fresh waters of rivers of average mineralization. An excess of the maximum permissible concentration for sulfates, nitrates and iron compounds was detected. It is shown that the hydrochemical regime of the studied water body is interconnected with level and thermal regimes and is influenced by anthropogenic factors. The data obtained are necessary to identify patterns of distribution of substances in natural geosystems located in the Malka River basin, of which the Baksan River is a first-order tributary.

Состав и структура фитопланктона Сылвенско-Чусовского плеса Камского водохранилища (Россия)

Based on the materials from studies of phytoplankton in the SylvenskoChusovsky reach of the Kama Reservoir in July 2020 and 2022, its taxonomic composition, ecological-geographical structure and quantitative indicators were studied. The large marginal Sylvensko-Chusovsky reach of the Kama Reservoir is formed by the confluence of the Sylva and Chusovaya rivers and includes two districts and three sections (See Fig. 1). The mineralization of water throughout the reach varies significantly, from 225 to 1000 mgL-1, which is associated with the influx of river water. In the Sylva River, the average mineralization values in summer are significantly higher (650 mgL-1) than those of the Chusovaya River (250 mgL-1). Precipitation and surface inflow volumes in the study area (July 2020 and 2022) were below long-term averages. The years of research varied significantly in temperature regime: the water temperature of the Sylvensko-Chusovsky reach in 2020 was 30.3 ± 1.6°С, in 2022 – 20.3 ± 0.6°С. As a result of the study, 267 species and intraspecific taxa of algae from 9 departments were identified in the phytoplankton composition of the Sylvensko-Chusovsky reach of the Kama Reservoir. The basis of the species richness was formed by diatoms (36.0%), green (28.5%), golden (12.5%) algae, and cyanoprokaryotes (11.6%); the share of other algae departments totaled 11% (See Table 1). The species composition of phytoplankton differs in various parts of the reach, which is associated with the flow of river waters from the Sylva and Chusovaya rivers into the bays; the degree of floristic similarity according to the Sørensen-Chekanovsky coefficients is low and ranges from 0.41 to 0.68 (See Fig. 2). As a result of the carried-out work, the floristic list of algae of the Sylvensky Bay was replenished by 41%, previously numbering 69 species and varieties from 5 departments (See Fig. 3). In the ecological and geographical aspect, the algal flora of plankton is represented by typically planktonic species, widespread in water bodies of the globe, indifferent to water salinity, living only in fresh water bodies and preferring neutral waters (See Table 2). In Sylvensky Bay, the ecological structure of algocenoses retained its proportions from 2004 to 2022. During the summer low-water period of algal flora, the most significant contribution is made by cyanoprokaryotes, which appear with diatoms and green sea waves (See Fig. 4). Quantitative indicators of phytoplankton development varied significantly: abundance from 0.9 to 85.0 million cellsL-1, biomass from 0.39 to 13.02 mgL-1. Differences in the temperature regime during the years of the study determined the level of phytoplankton development; in 2022, the abundance and biomass values were three times higher compared to the abnormally hot 2020 (See Table 3). Throughout the entire water area, the dominant complex in number is represented mainly by species indicators of anthropogenic eutrophication (Aphanizomenon flos-aquaе, Aphanocapsa holsatica, Aulacoseira granulata, Stephanodiscus binderanus) and there is a massive development of non-heterocyst cyanoprokaryotes (Aphanocapsa holsatica, A. inserta, Anathece clathrata, Planktolyngbya limnetica, A. phanothece bachmannii). Dinophyte algae (Apocalathium aciculiferum, Peridinium cinctum, P. willei, Peridinium sp. and Gymnodinium sp.) played a significant role in the composition of dominant species by biomass, along with diatoms (See Table 4). As a result of the development of smallsized algal species, phytoplankton abundance values have increased more than 20-fold from 2004 to the present, while phytoplankton biomass has increased only twofold. The Shannon species diversity index values (2.96-5.02) indicate a complex structure and high biodiversity of phytoplankton. Higher index values were characteristic of riparian areas in 2022. Simpson's indices, reflecting the degree of expression of dominance of certain species, vary from 0.04 to 0.36 in the Sylvensko-Chusovsky Bay. The decrease of the index in the Chusovsky Bay (0.15 ± 0.03) is associated with a higher diversity of phytoplankton compared to the Sylvensky Bay (0.23 ± 0.05). Based on the composition of structure-forming species and the level of biomass, the trophic status of the Sylvensko-Chusovsky reach is determined as mesotrophic. Since the distribution of phytoplankton across the water area is uneven, the trophic state was assessed from β-oligotrophic in the Sylvensko-Chusovsky area to mesotrophic in the bays in 2020, and from mesotrophic to α-eutrophic level in 2022. The main changes in phytoplankton include a significant increase in the taxonomic diversity of golden algae, an increase in the coenotic role of disazotrophic cyanoprokaryotes and dinophyte algae, which indicates the progressive eutrophication of the waters of the Sylvensko-Chusovsky reach under the combined influence of anthropogenic factors and climate warming.

ASSESSMENT OF THE HYDROGEOLOGICAL CONDITIONS OF THE KARABAGH-MIL PLAIN

Mil-Karabagh plain, the studied territory, located to the north-east from the piedmont of the Lesser Caucasus. The main irrigation canals of the region, including the bed of the Yukhari-Karabagh canal, have high water permeability, as they are built from local soils. This ensures that surface and underground waters interact, feeding each other along the flow. The amount of precipitation in different parts of the Karabagh plain was 370-453 mm, and they fall unevenly in different seasons. Thus, the maximum amount of precipitation is observed in autumn and spring, and the minimum amount of precipitation is observed in winter and summer. There are 6 aquifers (water-bearing horizons) in the upper part of the Mil plain: 1 underground, 5 confined aquifers. The underground and three confined aquifers are associated with the Quaternary period, the fourth aquifer is associated with the Absheron, and the fifth with Aghjagil stages sedimentary rocks. The variability of the level mode is fully studied here. Sources of formation of underground water resources and methods of their effective use have been identified to a sufficient level. The horizon of underground waters and water strikes form a single water horizon in the elevated parts of river tributaries. The water deposits mentioned here are composed of boulder-gravel-pebble stones according to their lithological composition, clay and clayey deposits are rare. These deposits are found at depths of up to 110 m and more. The degree of natural drainage of the territory is one of the main factors influencing soil reclamation, depending on the geological structure, geomorphological conditions and features of the relief. The Karabagh irrigation massif is served by the Mil-Karabagh reservoir. Which discharges drainage water with an average mineralization of 12.7 g/l to 200 million m3 per year. Occurrence depth of the groundwater within the territory of the Karabagh irrigation massif 0-10 m and deeper from surface. There is a tendency to decrease the depth of groundwater in the area from the south-west to the north-east, i.e. from the piedmont to the Kura river. Keywords: underground water, rural economy, drainage, water strikes, hydrogeological basin.

Classification of bottled waters marketed and consumed in Algeria through statistical approaches.

The main objective of this work consists of classifying 30 brands of water bottled and marketed in Algeria, based on their physicochemical compositions and their comparison with some foreign brands recognized in their countries or on a world scale. Relevant to this, descriptive statistics, as well as hierarchical ascendant classification (HAC) and principal component analysis (PCA), were used to analyse the data. The results of this study highlighted a similarity between some Algerian brands and other foreign brands of water in terms of mineral content. Moreover, the results obtained by using PCA and HAC allowed us to divide the sample of Algerian mineral waters into three distinct groups, each with similar physicochemical characteristics. The first group (Soummam, Manbaa Al Ghezlane, Mouzaia, Amane, Djmila, and Hayet) is characterized by very high levels of mineral salts compared to the other brands. The second group (Guedila, Tazliza, Arwa, Baniane, Saida, Ifri, Messerghine, Sfid, Mansourah, Batna, Mileza, S. Rached, Dhaya, Qniaa, and Lejdar) is distinguished from the first group by its average mineralization. Finally, the third group (Fezguia, Nestlé, Ovitale, L. Khedidja, A. Bouglez, Ayris, Righia, Togi, and Toudja) presents a very low mineralization.

Anions Cations Balance in Rainwater of Lanka, Mirzamurad and Babatpur, Varanasi

The analysis of anions cations balance in rainwater samples, were carried out in the Department of Soil Science and Agricultural Chemistry Laboratory at the Institute of Agricultural Sciences, Banaras Hindu University, Varanasi during 2015. The rainwater samples of three different location viz. Lanka, Mirzamurad and Babatpur places of BHU, Varanasi, which are relatively free from industrial pollution were examined during south-west monsoon period (July to September) in Varanasi using standaralize selection and analytical methods for evaluation of anions cations balance of rainwater. It was revealed from the Tables 1-3 that the total mineralization varied from 53.65 to 171.38 mg L-1 in Lanka, 25.49 to 153.55 mg L-1 in Mirzamurad and 73.32 to 286 mg L-1 in Babatpur, respectively. In an average total mineralization was highest in Babatpur followed by Lanka and Mirzamurad.

Hydrochemical characteristics of the Upper reaches of the Tisza River


 
 
 The purpose of this study is to analyse the hydrochemical regime and surface water quality of the upper reaches of the Tisza River from its source to Tiachiv, which also includes the transboundary section of the river. The data of the Borys Sreznevskyi Central Geophysical Observatory of the State Emergency Service of Ukraine for the period 1984-2018, as well as the results of route surveys during 2015-2018 served as materials for the study. The hydrological parameters of the river, in particular the level and flow of water, the distribution of the flow and the change of power sources throughout the year were analysed. Based on of the collected materials, a detailed analysis of the hydrochemical indicators of the water quality of the Tisza, Black Tisza, and White Tisza rivers was carried out. During the research, the natural conditions of the territory and economic activity were studied and their influence on the values of physic-chemical indicators, main ions and mineralization of water, biogenic substances, heavy metals and specific pollutants was analysed. The ratio of seasonal, average annual, average multi-year and maximum permissible concentra-tions (MPC) of hydro-chemical indicators was considered to determine their seasonal variability and multi-year dynamics. The role of natural factors in the formation of the chemical composition of river waters is determined, and the main sources of anthropogenic influence are also indicated. Seasonal variability of the indicated groups of indicators was also analysed considering different phases of river water content. It was determined that the waters of the headwaters of the Tisza River are calcium carbonate, moderately fresh with average mineralization (192-245 mg∙dm-3) and clear seasonal variability. Cases of increased concentrations of nitrogen-containing compounds in the waters of the upper reaches of the Tisza River due to the intensive decomposition of organic substances from house- hold wastewater were revealed. High concentrations of iron in river waters were recorded, which is related to the peculiarities of the geological structure of the territory. The seasonal variability of the content of synthetic surfactants was established. A decrease in the content of specific pollutants during the study period was observed.
 
 

Effect of tillage minimisation on the carbon balance in the soil in the forest-steppe of the Novosibirsk Ob region

The study aimed to assess the carbon balance in leached chernozem when used in a long-term field experiment in 2 variants: with annual ploughing to a depth of 25 – 27 cm and surface treatment by 6 – 8 cm. In the experiment, spring wheat was grown using intensive technology in a crop rotation, pure fallow - wheat - wheat. The variants of the experiment differed in the number of plant residues: straw was removed from half of the fields, and on the other half, it was planted and crushed into the soil after harvesting. The authors estimated the carbon balance based on the element’s input into the ground with plant residues (straw and roots) and its losses in the form of CO2 from the soil’s organic matter during the growing season. The total loss of С–СО2 for the period May – September was calculated based on the average daily rate of production of СО2 , which was determined in the field of pure fallow once a week by the absorption method. Minimization, the transition from ploughing to surface tillage, did not significantly impact the average annual wheat yield (2.49 – 2.60 t/ha) and the number of plant residues (1670 – 1818 kg C/ha of arable land). Also, between these treatment backgrounds, no significant differences were found in the average annual mineralization of organic matter and the carbon balance in the soil. These indicators depended only on the amount of plant matter (straw and roots) entering the ground. The poor credit of carbon in the land (-752 kg C/ha of arable land) was registered when straw was alienated from the field. When it was left on the field, the balance of the element became much more favourable (-88 kg C/ha of arable land), approaching a deficit-free state. The authors concluded that a carbon balance close to a deficit-free one was ensured, regardless of the primary tillage with an average annual wheat yield in a 3-field grain-fallow crop rotation of about 2.5 t/ha of grain and the incorporation of the entire non-marketable part of the crop into the soil in the leached chernozem.

Experimental Study on the Purification Mechanism of Mine Water by Coal Gangue

Coal mining has caused groundwater pollution and loss. Using a mined area as a water storage space for storing and purifying mine water is a low-cost environmentally friendly mining method. In this study, static and dynamic adsorption experiments on the ions in mine water were carried out using the roof rocks from the Lingxin coal mine. The sample analysis results show that the main chemical composition of the roof is mainly SiO2 and Al2O3. The water chemistry type of the mine water is SO4-HCO3-Cl-Na type, with an average mineralization of about 4000 mg/L. The experimental results show that gangue can stabilize the pH value of mine water with different pH values between 7.5 and 8.5. In the acidic and alkaline environment, the degree of void space increases the adsorption capacity of the gangue, in which the adsorption rate of gangue is between 3% and 5%. The calcium ion reduction rate reaches 75% in static leaching and 70% in dynamic leaching conditions. Medium-grained coarse sandstone has a stronger adsorption capacity than muddy siltstone. The results from this study can support further research on using gangue for water purification purposes in mines, simultaneously reducing the harmful accumulation of gangue and promoting the recycling of highly mineralized water.

ХАРАКТЕРИСТИКА ХІМІЧНОГО СКЛАДУ ВОДИ ТА ГІДРОХІМІЧНОГО РЕЖИМУ ЛІВОБЕРЕЖНИХ ПРИТОК ДНІСТРА В МЕЖАХ ТЕРНОПІЛЬСЬКОЇ ОБЛАСТІ

The article is devoted to the study of the chemical composition of water, the hydrochemical regime and water quality of the left-bank tributaries of the Dniester within Ternopil region (Zolota Lypa, Koropets, Strypa, Seret, Nichlava and Zbruch rivers) based on water monitoring data of the State Water Agency of Ukraine (1993-2020). The chemical composition of water was studied according to: main ions and water mineralization; physical and chemical parameters (pH, O2); biogenic substances ((NН4+, NO2–, NO3–, РO43–); trace elements (Cu, Cr); specific pollutants (petroleum products, detergents). It was established that the hydrochemical type of water in most of the studied rivers is calcium bicarbonate. The water of the Nichlava River is calcium bicarbonate-sulfate. The average annual water mineralization of the studied rivers varies from 476 mg/dm3 to 699 mg/dm3. The water of most rivers is moderately fresh in terms of mineralization. The water of the Nichlava River is fresh with high mineralization. The hydrochemical regime of rivers is related to the hydrological regime. The minimum concentrations of the main ions and water mineralization are observed during the summer-autumn mezhenia, which is explained by the precipitation of a significant amount of atmospheric precipitation and the presence of floods during this period. The maximum of these indicators is observed in winter. The hydrochemical regime for biogenic substances, trace elements and specific pollutants is less pronounced. Among biogenic substances, the clearest manifestation of the hydrochemical regime was recorded for nitrates. The minimum concentrations of NO3– are observed in the summer-autumn boundary, when nitrates are consumed for the development of aquatic plants. Nitrates accumulate in the autumn period with the death of aquatic plants, and during the winter period, their maximum average content is observed. The assessment of the water quality of the studied rivers, carried out by analyzing long-term series of observations using the “Hygienic water quality standards of water bodies … (2022), showed that the content of the studied components mainly met the regulatory requirements, with the exception of iron. At the same time, the absence of copper, chromium, petroleum products and detergents in water was recorded in all studied rivers during the observation period in different years (zero values of these components were recorded in 70-90% of samples).

Применение методов пространственного анализа для определения средней минерализации подземных вод Курганской области

In the Kurgan region there is a shortage of water resources and the issue of water supply is particularly acute in rural areas. Such a situation leads to an increase in water-related diseases and may result in an intensification of migration from the region. The aim of this study is to identify the correlation between the level of mineralization in the underground water used for drinking water supply in rural settlements of the region and the incidence of diseases among the population. As a result of the research, a map of the average mineralization of the first aquifer in the Kurgan region was created. A spatial analysis was conducted, which showed the proportion of areas with different levels of mineralization within the region. A correlation between the average mineralization of underground water and the incidence of diseases among the rural population of the region was established.

Taxonomic diversity and structure of phytoplankton in different-type lakes of Kulunda basin (Altai krai)

In the phytoplankton of different-type lakes of Kulunda basin 87 species and 1 variety of algae from 6 systematic divisions were identified: Cyanobacteria, Bacillariophyta, Cryptophyta, Euglenophyta, Chlorophyta and Ochrophyta. The most diverse in the number of families, genera and species is the Cyanobacteria (35 species, or 40.2 % of the total number of species), as well as Chlorophyta (26, or 29.9 %), Bacillariophyta (17, or 19.5 %). Most of the taxa ranked above the family belong to Bacillariophyta (2 classes, 3 subclasses, 9 orders) and Chlorophyta (3 classes, 8 orders). The two divisions are not numerous, they have only 2 (Cryptophyta) and 3 (Ochrophyta) species. The largest family is Oscillatori-aceae with 4 genera and 13 species. The leading genera include 5 genera, and 3 of them are from Cyanobacteria, 1 genus each belong to Chlorophyta (Ulothrix) and Bacillariophyta (Nitzschia). According to the results of the study, the dependence of the number of species in phytoplankton on the average mineralization and Wolf Number (the measure of solar activity) for salt lakes in Kulunda basin was revealed.

Removal of Gaseous Volatile Organic Compounds by a Multiwalled Carbon Nanotubes/Peroxymonosulfate Wet Scrubber.

In this study, a wet scrubber coupled with a persulfate-based advanced oxidation process [carbocatalysts/peroxymonosulfate (PMS)] was demonstrated to efficiently remove gaseous volatile organic compounds (VOCs). The removal efficiency of a representative VOC, styrene, was stable at above 98%, and an average mineralization rate was achieved at 76% during 2 h. The removal efficiency of the carbocatalysts/PMS wet scrubber for styrene was much higher than that of pure water, carbocatalysts/water, or PMS/water systems. Quenching experiments, electron spin resonance spectroscopy, in-situ Raman spectroscopy and density functional theory (DFT) calculations indicated that singlet oxygen (1O2) and oxidative complexes are the main reactive oxygen species and that both contributed to styrene removal. In particular, carbonyl groups (C═O) in the carbocatalyst were found to be the active sites for activating PMS during styrene oxidation. The role of 1O2 was discovered to be benzene ring breaking and a possible non-radical oxidation pathway of styrene was proposed based on time-of-flight mass spectroscopy which was further verified by DFT calculations. In particular, the electron transfer process of multi world carbon nanotubes-PMS* in styrene oxidation was further studied in-depth by experiments and DFT calculations. The unstable vinyl on styrene was simultaneously degraded by the oxidative complexes and 1O2 into benzene, and finally oxidized by 1O2 into H2O and CO2. This study provides an effective method for VOC removal and clearly illustrates the complete degradation mechanism of styrene in a nonradical PMS-based process by a wet scrubber.

Changes in soil carbon mineralization related to earthworm activity depend on the time since inoculation and their density in soil

Earthworms play a key role in soil carbon mineralization, but their effect is highly uncertain and suspected to vary as a function of several factors, particularly the earthworm density and time from earthworm inoculation. We conducted a meta-analysis considering these factors based on 42 experiments comparing carbon mineralization in the absence and presence of earthworms at different times. The results reveal an average carbon mineralization increase of 24% (sd 41%) in the presence of earthworms with an initial median earthworm density of 1.95 mg/g soil DM (Dry Mass) (sd 48%). We show that carbon mineralization due to earthworms was related to their density and time from inoculation. From a simple regression model using these two variables, the estimated impact of earthworms on carbon mineralization was 20% increase from 0 to 60 days and 14% decrease at day 350 for a density of worms commonly found in soils (0.5 mg/g soil DM). Finally, we proposed a simple equation that could be used in organic matter decomposition models that do not take macrofauna into account.

Quorum sensing improved the low-temperature performance of biofilters treating gaseous toluene

Biofilters usually have poor VOC removal performance at temperatures lower than 20 °C. In this study, two quorum sensing (QS) enhancement methods, which are addition of exogenous N-acyl-homoserine lactones (AHLs) and inoculation of AHL-producing bacteria, were applied in biofilters treating gaseous toluene at a low temperature of 12 °C. Their effects on biofilter performance and biofilm characteristics were investigated. The results showed that adding exogenous AHLs and AHL-producing bacteria in biofilters raised the average toluene elimination capacity by 39% and 26% respectively, and raised the average mineralization efficiency by 25% and 47% respectively in first 24 days. In addition, the two QS enhancement methods could increase the attached biomass by 48% and 87% respectively and made the biofilm distribute more uniform by increasing its extracellular polymeric substances content and microbial adhesive strength. The two QS enhancement methods resulted in more mesopores in biofilm, lower O/C and (O+N)/C of organic elements in biofilm, and increased the solubility of toluene in liquid phase, which all benefit VOCs mass transfer in biofilters. These results demonstrate that QS enhancement methods have the potential to optimize the biofilm and thus improve the performance of biofilters treating VOCs at a low temperature. This work provides us a new choice to improve industrial-scale biofilters treating VOCs at high latitude regions or in winter.

Impact of anthropogenic activity on the chemical regime of underground waters


 
 
 
 The article is dedicated to definition of the tendency to change and pattern of formation of the chemical regime of underground waters in the Turyanchay-Girdimanchay interfluve in the Shirvan steppe, Azerbaijan as a result of anthropogenic activity. The subsoil waters studied are spread in the zone between the Turyanchay and Girdimanchay rivers. From 1930 to 2019 based on analysis of the observation of the chemical regime of subsoil waters, the natural regime of the groundwaters in the studied area strongly changed as a result of irrigation and construction works. In 1930 the average mineralization degree of subsoil waters was 26.8 gram/liter in the zone. The level of subsoil waters approaches the surface and is exposed to strong evaporation as a result of irrigation and filtration of waters from irrigation channels. Consequently, the mineralization rate of subsoil waters increased and mass secondary salinization process occurred in the irrigated lands. The average mineralization degree of subsoil waters was 33.6–34.5 gram/liter in the research zone in the 1960s-1970s. Collector-drainage networks were built and basic washing of soils is carried out in order the prevent secondary salinization and regulate the level of subsoil waters. After the 1970s the mineralization rate of subsoil waters began to decrease due to basic washing, intensive irrigation and the activity of the collector-drainage network.The average mineralization degree decreased to 15.1 gram/liter. The mineralization degree of the water in the Main Shirvan Collector which takes subsoil waters formed in the zone with 253,000 hectares and which discaharges them into the Caspian Sea decreased more than 3 times in comparison with 1995. At present the mineralization degree of collector water is 1.8–2.5 gram/liter while its mineralization degree was 8.81 gram/liter in 1995. Formation of the process in a favourable direction enchances the potential of using collector water for irrigation, technical and other purposes and creates a basis for elimination of water deficiency in drought years. The research shows that anthropogenic activity mainly plays an important role in formation of the chemical regime of subsoil waters.
 
 
 

NRG COSIA Carbon XPRIZE: carbon-dioxide mineralization in recycled concrete wash water

Abstract Wash water is generated as a waste stream from ready-mixed-concrete production. Reuse of the water as mixture water is limited, in practice, by the negative material performance impacts associated with the water chemistry and properties; the effects are intensified with increasing content of suspended solids and age. However, this waste material can be used as a beneficial additive to concrete by profiting from the cementitious properties of the suspended solids, if variability can be reduced. A method of stabilizing this material is through CO2 treatment. The added CO2 is mineralized through a reaction with the calcium from the cement particles. This provides a calcium-carbonate coating that prevents further cement hydration, making the material predictable. This has been shown to alleviate concerns with set acceleration and inconsistencies in compressive strength. A method of CO2 treatment was tested as part of the NRG COSIA Carbon XPRIZE at a site in Calgary, Alberta. The slurry for the treatment was provided by a local concrete plant and had a specific gravity of 1.15. The simulated wash water was treated in 1000-L quantities with each treatment mineralizing an average of 40 kg of CO2. The system ran for 1600 hours of operation over 127 treatment cycles and converted 14.5 tonnes of CO2 at an average mineralization efficiency of 80%. The treated slurry was used as an additive in >300 batches of concrete where the concrete met the necessary requirements for fresh properties and setting time, while achieving a strength benefit. Replacement of 5% and 10% of batch water with treated slurry (9.4 and 18.8 kg slurry/m3 concrete) showed a strength benefit of 3% and 6% compared to a reference. The technology was selected as the winner of the NRG COSIA Carbon XPRIZE (Track B: Natural Gas) in April 2021.

Microbial Degradation Rates of Natural Bitumen.

Microorganisms are present in nearly every oil or bitumen sample originating from temperate reservoirs. Nevertheless, it is very difficult to obtain reliable estimates about microbial processes taking place in deep reservoirs, since metabolic rates are rather low and differ strongly during artificially cultivation. Here, we demonstrate the importance and impact of microorganisms entrapped in microscale water droplets for the overall biodegradation process in bitumen. To this end, we measured degradation rates of heavily biodegraded bitumen from the Pitch Lake (Trinidad and Tobago) using the novel technique of reverse stable isotope labeling, allowing precise measurements of comparatively low mineralization rates in the ng range in microcosms under close to natural conditions. Freshly taken bitumen samples were overlain with artificial brackish water and incubated for 945 days. Additionally, three-dimensional distribution of water droplets in bitumen was studied with computed tomography, revealing a water bitumen interface of 1134 cm2 per liter bitumen, resulting in an average mineralization rate of 9.4–38.6 mmol CO2 per liter bitumen and year. Furthermore, a stable and biofilm-forming microbial community established on the bitumen itself, mainly composed of fermenting and sulfate-reducing bacteria. Our results suggest that small water inclusions inside the bitumen substantially increase the bitumen–water interface and might have a major impact on the overall oil degradation process.