Concentrations Of Chemical Components Research Articles

Evaluating The Impact of Increased Heavy Oil Consumption on Urban Pollution Levels through Isotope (δ13C, δ34S, 14C) Composition

The impact of heavy fuel oil (HFO) on the chemical and isotopic composition of submicron particulate matter (PM1) was investigated. For this purpose, we conducted an analysis of water-soluble inorganic ions (WSIIs) and multiple isotopes (δ34S, δ13C, 14C) of PM1 and SO2 collected during two heating periods: before (2021–2022) and during the use of HFO (2022–2023) in Vilnius, Lithuania. The results showed that the combustion of HFO increased the concentrations of SO₂ (by 94%) and PM1-related sulfate (by 30%). It also altered the chemical composition of PM1, with sulfate becoming the predominant component (~40%) of WSIIs. The stable sulfur isotope ratios of SO2 (δ34SSO2) and sulfate (δ34SPM1) shifted significantly to more negative values (δ34SSO2 = 0.4‰, δ34SPM1 = −0.3‰) compared to the previous heating period. Anticorrelation between δ¹³C and δ³⁴S values indicated increased contributions of ¹³C-enriched fossil fuel sources (coal and HFO) in EC, although the share of fossil fuels in elemental carbon (EC) slightly decreased during the HFO period. The combustion of HFO affected the concentrations of PM1 chemical components and substantially impacted the isotopic composition and source contributions of sulfate and EC.

Hydrochemical characterization and comprehensive water quality assessment of groundwater within the main stream area of Yishu River.

To gain a comprehensive understanding of the hydrochemical characteristics, controlling factors, and water quality of groundwater in the main stream area of Yishu River (MSYR), a study was conducted using water quality data collected during both the dry and wet seasons. Through statistical analysis, hydrochemical methods, fuzzy comprehensive evaluation, and health risk evaluation modeling, the water chemical characteristics of the main stream area of Yishu River were studied, and the water quality of the area was comprehensively evaluated. The findings indicate that HCO3- and Ca2+ are the predominant anions and cations in the MSYR during the dry and wet seasons, respectively. Moreover, anion concentration in groundwater follows HCO3- > SO42- > NO3- > Cl-, while cations are ranked as Ca2+ > Na+ > Mg2+ > K+. Overall, the groundwater manifests as weakly alkaline and is predominantly classified as hard-fresh water. During the wet season, there is greater groundwater leaching and filtration, with rock and soil materials more readily transferred to groundwater, and the concentrations of main chemical components in groundwater are higher than those during the dry season, and the hydrochemical types are primarily characterized as HCO3-Ca·Mg and SO4·Cl-Ca·Mg types. These results also suggest that the chemical composition of the groundwater in the MSYR is influenced mainly by water-rock interaction. The primary ions originate from the dissolution of silicate rock and carbonate rock minerals, while cation exchange plays a critical role in the hydrogeochemical process. Groundwater in the MSYR is classified mostly as class II water, indicating that it is generally of good quality. However, areas with high levels of class IV and V water are present locally, and NO3- concentration is a crucial factor affecting groundwater quality. In the wet season, more groundwater and stronger mobility lead to greater mobility of NO3- and wider diffusion. Therefore, the risk evaluation model shows that nitrate health risk index is higher in the wet season than it is in the dry season, with children being more vulnerable to health risks than adults. To study groundwater in this area, its hydrochemical characteristics, water quality, and health risk assessment are of great practical significance for ensuring water safety for residents and stable development of social economy.

Study of the concentration of creatinine and some electrolytes in the blood serum of healthy males in the city of Sabratha

Most researchers usually investigate the concentration of chemical components in the blood of people suffering from a disease, and studies are rarely conducted in healthy people. So the researchers conducted this preliminary statistical study of both creatinine and some electrolytes in the blood serum of a group of healthy males. Years 25 samples of healthy male blood were collected in Sabratha city. Their average age was 13.64, 41.92, The concentration of sodium, chloride, potassium., magnesium ions, and creatinine ions were measured in the blood serum of each volunteer in the hospital the city of Sabratha. The mean and deviation were standard for the concentrations of these chemical components, respectively: (5.15, 140.62 mmol /L, 3.98 (106.80) ) mmol /L, 0.74 4.60 ) mmol /L, 0.18 2.06) milligram / dL ), 0.17 0.84) milligrams / dL. When compared to internationally accepted reference values, the results showed the necessity of working to determine the concentration of creatinine, sodium, and potassium. And chloride through the serum of healthy males in Sabratha and then Libya. In the case of magnesium, it seemed clear that the internationally accepted reference value was sufficient for the purpose. The limits of the reference values were determined for the concentration of sodium, chloride , potassium ions , and the concentration of creatinine , and they were, respectively, (126.6, 149.8) mmol /L, (97.1,114.7) mmol /L, (2.9,6.0) mmol /L, (0.4,1.1) Milligrams / dL, and these limits were wider compared to the limits of reference values used in laboratories. The type of relationship between the study variables was also determined using the person correlation coefficient) , and this relationship) was confirmed graphically using what is known as in kilograms , the concentration of sodium and chloride ions was more interconnected and similar.

Effect of pH variation on chemical components and antifungal activity of ketepeng cina (Cassia alata L.) leaves extract

Ketepeng cina (Cassia alata, L.) has been widely used as a traditional medicine, one of which is as an antifungal. Previous research showed problems with the storage of ketepeng cina leaves extract, which reported changes in pH and color over time. This study explored the effect on concentration of chemical components and antifungal activity under varying pH. Antifungal activity against Candida albicans was tested using microdilution and well diffusion methods. HPTLC technique was measured the chemical components of the extract represented by aloe-emodin and kaempferol concentration. The extract with pH 4.5 had the highest aloeemodin content and antifungal activity. The result of our research were the pH variation significant influence on anti fungal activity against C.albicans, where the best results are at pH 5.5 (p<0.05). The level of active components in the extract is influenced by the pH conditions (p<0.05). Specifically, the levels of kaempferol and aloe-emodin are maximum at a pH of 5.5. It can be concluded that pH can affect the levels of chemical components and antifungal activity in ethanol extracts of ketepeng cina (Cassia alata, L.) leaves.

Use of essentialoils in meatprocessing

Essential oils are natural plant products with rich chemical composition and various properties. They are obtained by extraction from plant parts such as flowers, buds, stems, twigs, seeds, fruits, roots, bark and leaves. They contain over sixty organic compounds with low molecular weight, including: phenolic and terpene compounds, aliphatic alcohols, aldehydes, ketones, acids and isoflavonoids. The composition, concentration and proportions of chemical components in essential oils determine their properties. Essential oils have a significant impact on living organisms, including antiviral, antibacterial, antifungal, antiparasitic, anti-inflammatory and antioxidant properties. Depending on the concentration used, essential oils positively or negatively affect the sensory properties of meat products. It is important to obtain a sensorially acceptable concentration of essential oil in the product, which will also ensure effective antimicrobial activity. By applying several essential oils at the same time or using other preservatives or preservation and packaging methods with them, a synergistic effect can be achieved, thanks to which the concentration of the essential oil in the product can be reduced. Factors that can influence the antimicrobial effect of essential oils in food products include: food structure, composition, pH, storage conditions and the type of saprophytic microbiota in the product. Essential oils can have a positive impact on the microbiological quality of food and can be used in the food industry as a factor inhibiting the growth of saprophytic microorganisms that affect the durability of food and pathogenic bacteria that cause food poisoning.

Alizarin Red S, Oxalic Acid and Cetylpyridinium Chloride-based Modified Photogalvanic Cell with Sustainable Conversion and Storage of Solar Energy

In this study, an integrated photogalvanic system of Alizarin red S, oxalic acid and cetylpyridinium chloride has been fabricated and used for the conversion of solar energy in to electrical energy with improved conversion efficiency and storage capacity. The photogalvanic cell is an H-shaped glass tube cell containing two electrodes dipped in a multifaceted electrolyte solution of dye-reductant-surfactant-alkali. By virtue of its photogalvanic action, it is capable of being charged by sun light. This system by way of variable concentration of chemical components were used to formulate a modified photogalvanic cell. The modified cell indicated significantly improved performance in terms of dark potential (778 mV), open-circuit potential (1189 mV), short-circuit current (420 µA), power (147.42 µW), charging time (17 min), half change time (16 min), conversion efficiency (2.16%) and fill factor (0.299).

Polylysine‐Coated Surfaces Drive Competition in Chemical Reaction Networks to Enable Molecular Information Processing

AbstractThis work describes a competing activation network, which is regulated by chemical feedback at the liquid‐surface interface. Feedback loops dynamically tune the concentration of chemical components in living systems, thereby controlling regulatory processes in neural, genetic, and metabolic networks. Advances in systems chemistry demonstrate that chemical feedback could be designed based on similar concepts of using activation and inhibition processes. Most efforts, however, are focused on temporal feedback whereas biological networks are maintained by the interplay between temporal and spatial organization. Here, we designed a feedback system comprising a simple acid‐base equilibrium that can be perturbed by two opposing activation processes. Crucially, one of the processes is immobilized on the surface of a microfluidic channel using poly‐l‐lysine (PLL). We measured the capacity of the PLL‐coated channels to resist changes in pH in flow using a pH‐sensitive indicator, phenol red, and showed that this capacity can be increased by employing polyelectrolyte multilayers. Specifically, we found that the rate of local activation (i. e., the deprotonation of the immobilized lysine residues) could be significantly increased to delay the otherwise fast equilibrium. This effect allowed for encoding read and write operations, providing the potential to bestow CRNs with the capacity of molecular information processing.

Characteristics of Atmospheric Dust Fall Pollution and Its Chemical Composition and Mass Reconstruction in Mentougou District of Beijing

To study the characteristics of atmospheric dust fall pollution in Mentougou District of Beijing, the monthly average monitoring results of 57 atmospheric dust fall samples from two state-controlled ambient air stations in Mentougou District from 2018 to 2022 were collected, and the atmospheric dust fall pollution status and its time variation characteristics in Mentougou District were analyzed. In order to explore the characteristics of chemical components of atmospheric dust fall and the results of quality mass reconstruction and their sources, 57 dust fall samples were collected using the active suction method at the Sanjiadian State-controlled Ambient Air Station. The mass concentration of dust fall and its chemical components were measured, the characteristics of chemical components in atmospheric dust fall were studied, and the mass reconstruction of the main components of atmospheric dust fall was performed using particle mass reconstruction technology. The reliability of the mass reconstruction results and the reasons for its undetermined components were also discussed. The results showed that from 2018 to 2022, the monthly dust fall in Mentougou District of Beijing changed periodically, being the maximum in April or May in spring and the minimum in October or November in autumn, and the maximum monthly dust fall was 3.2 to 8.4 times the minimum monthly dust fall. The order of the quarterly average monthly dust fall was as follows:spring>summer>autumn>winter, and the dust fall mainly came from spring and summer, accounting for 40.1%-43.0% and 23.8%-37.5% of the total annual dust fall, respectively. The annual average monthly dust fall in Mentougou District of Beijing showed a significant downward trend. The dust fall in 2022 had decreased by 52.8% compared with that in 2018, with an average annual decline of 13.2%, which was related to the improvement in the fine management level of urban environmental protection in Beijing in recent years. In 2021, soil dust had a significant impact on dust fall in Mentougou District, with an actual contribution of 44.2%. The chemical components in the atmospheric dust fall in Mentougou District were mainly water-soluble ions, crustal elements, organic carbon(OC), and elemental carbon(EC). The total mass of the measured chemical components accounted for 65.0% of the mass fraction of the dust fall. The secondary organic carbon(SOC) was also an important component of the atmospheric dust fall, and its mass concentration was 13.5 μg·m-3, accounting for 96.4% of the mass fraction of OC. The main components of atmospheric dust fall mass reconstruction were crust element fugitive dust, organic matter(OM), SO42-, NO3-, NH4+, trace elements, EC, and Cl-, with mass concentrations of 34.8, 28.0, 20.6, 15.0, 5.6, 4.3, 3.2, and 2.2 μg·m-3, accounting for 25.5%, 20.6%, 15.1%, 11.1%, 4.1%, 3.2%, 2.3%, and 1.6% of the dust fall quality, respectively. The atmospheric dust fall mainly came from the soil dust, construction cement dust, biomass combustion, waste incineration, and secondary transformation process. The measured mass concentration of atmospheric dust fall had a good correlation with the reconstructed mass concentration of chemical components, and the determination coefficient R2 was 0.8173. The undetermined components in the mass reconstruction results accounted for 16.5% of the dust fall mass, of which the particle bound water(PBW) in the dust fall accounted for 6.2% of the dust fall mass, and the remaining undetermined components might have been related to the unmeasured components, the selected estimation coefficient of OM and crustal elemental dust, the particle size composition, the selected chemical component analysis method, and its measurement error.

Groundwater chemistry and isotope for interpreting the hydrogeological conditions and hydrochemical evolution of multilayer aquifer system of Donghai island, China

Groundwater is generally important water resource for islands. Groundwater recharge source and its hydrochemical characteristics are vital issues for the sustainable development and management of island groundwater resources. In this study, taking Donghai island which is featured with multi-layer aquifer structure as an example, by comprehensive using of statistical analysis, stable isotope (2H-18O), Gibbs diagram and ion ratio graph, we conducted a comprehensive hydrochemistry investigation for the groundwater in the shallow aquifer (i.e., phreatic and feeble confined aquifers) and middle confined aquifer of this island. And the hydrochemical characteristics, recharge sources, hydrogeochemical processes and source of element components of groundwater in different aquifers of Donghai island were identified. The results show that the major ions and TDS of the shallow groundwater are higher than those of the confined groundwater, and that those aquifers have not suffered significant seawater intrusion. The main hydrochemical types of shallow groundwater and confined groundwater are Cl·SO4-Ca·Na and HCO3-Na·Mg, respectively. Different hydrochemical types and chemical component concentrations between these two aquifers indicate that the hydraulic relationship between aquifers is relatively weak. The results of 2H-18O stable isotope and deuterium excess indicate that the shallow groundwater originated from local precipitation and that the recharge period of the confined groundwater is different from the shallow groundwater. Results of ion ratio reveal that the island groundwater hydrochemistry is mainly controlled by the water-rock interaction, featuring with dissolution of silicate rocks (such as sodium feldspar, potassium feldspar, calcium feldspar and biotite). In addition, cation exchange is also an important hydrogeochemical process controlling the hydrochemical composition of the confined groundwater. The results will be helpful for understanding of the local island hydrogeology and be supportive for the groundwater resources quantitative research such as numerical modeling for Donghai island.

Rapid Urbanization Has Changed the Driving Factors of Groundwater Chemical Evolution in the Large Groundwater Depression Funnel Area of Northern China

With the rapid development of urbanization, the chemical evolution of groundwater has been significantly affected by human activities. However, the driving mechanisms of groundwater chemical evolution at different stages of urbanization are still unclear, which severely affects the implementation of groundwater protection. This study investigated the driving mechanisms of groundwater chemical evolution based on the long-term series (from 1985 to 2015) of hydrochemical data from 19 groundwater monitoring sites in rapidly urbanizing areas (Shijiazhuang, Hebei Province, China). The results show that the concentrations of various chemical components in groundwater gradually increase with the acceleration of the urbanization process, especially NO3−, which has increased from 13.7 mg/L in the primary stage of urbanization (PSU) to 65.1 mg/Lin the advanced stage of urbanization (ASU), exceeding the World Health Organization (WHO) drinking water standard (50 mg/L), indicating that the groundwater chemistry has been significantly affected by human activities. The main hydrochemical types have changed from the HCO3•SO4-Ca•Mg-type water in the primary stage of urbanization (PSU) to the SO4•HCO3-Ca•Mg-type water in the advanced stage of urbanization (ASU). It is worth noting that there are obvious differences in driving factors of groundwater chemical evolution at different urbanization stages. In the primary stage of urbanization (PSU), the driving factors were carbonate and rock salt dissolution, cation exchange, and industrial activities. However, in the intermediate stage and advanced stage, the driving factors were changed to carbonate and gypsum dissolution, groundwater over-exploitation, agricultural fertilization, and domestic sewage. Based on the above conclusions, it is suggested that future groundwater management should control the amount of agricultural fertilizers, apply scientific fertilization, and prohibit the discharge of various types of non-compliant sewage, while strengthening the supervision of groundwater extraction to reduce the impact of urbanization development on the groundwater chemical evolution process.

Spatial-temporal evolution patterns and drivers of PM2.5 chemical fraction concentrations in China over the past 20 years.

The quantitative assessment of the spatial and temporal variability and drivers of fine particulate matter (PM2.5) fraction concentrations are important for pollution control and public health preservation in China. In this study, we investigated the spatial temporal variation of PM2.5 chemical component based on the PM2.5 chemical component datasets from 2000 to 2019 and revealed the driving forces of the differences in the spatial distribution using geodetector model (GD), multi-scale geographically weighted regression model (MGWR), and a two-step clustering approach. The results show that: the PM2.5 chemical fraction concentrations show a trend of first increasing (2000-2007) and then decreasing (2007-2019). From 2000 to 2019, the change rates of PM2.5, organic matter (OM), black carbon (BC), sulfates (SO2- 4), ammonium (NH+ 4), and nitrates (NO- 3) were -0.59, -0.23, -0.07, -0.15, -0.02, and 0.04μg/m3/yr in the entirety of China. The secondary aerosol (i.e., SO2- 4, NO- 3, and NH+ 4; SNA) had the highest fraction in PM2.5 concentrations (55.6-68.1% in different provinces), followed by OM and BC. Spatially, North, Central, and East China are the regions with the highest PM2.5 chemical component concentrations in China; meanwhile, they are also the regions with the most significant decrease in PM2.5 chemical fraction concentrations. The GD and MGWR model shows that among all variables, the number of enterprises, disposable income, private car ownership, and the share of secondary industry non-linearly enhance the differences in the spatial distribution of PM2.5 component concentrations. Electricity consumption has the strongest influence on NH+ 4 emissions in Northwest China and BC and OM emissions in Northeast China.

Results of statistical analysis of primary components concentrations in bulk chemical composition of ordinary chondrite groups

AbstractWe used two different methods of statistical analysis—cluster analysis and principal component analysis—to analyze the concentrations of principal chemical components (Si, Mg, Ca, Fe, Ni) and Co in ordinary chondrites. The analysis is based predominantly on published data (metadata). In total, chemical composition data from 646 ordinary chondrites were used in the statistical analysis. The aim of this analysis was to establish whether it would be possible or not to distinguish H, L, and LL chondrites based on the concentrations of major elements and Co in their bulk chemical compositions. It was also important to determine what conclusions such an analysis could enable to draw about matter differentiation in the formation environments of primordial parent bodies of particular ordinary chondrite groups (H, L, and LL). Another aim of the statistical analysis was to determine whether the distribution of Fe and Ni (with Co admixtures) is independent of petrographic types within particular groups of chondrites. This is of crucial importance for determining the distribution of FeNi(Co) ore occurrences in potential extraterrestrial deposits on modern asteroids—the sources of ordinary chondrites. The obtained results of statistical analyses confirmed that a clear‐cut distinction between particular groups of ordinary chondrites is only possible for group H, while distinguishing L chondrites from LL chondrites is not always obvious. The results of the statistical analyses relating to the question of the possible existence of several primordial parent bodies (formation environments) of each group of ordinary chondrites are consistent with the results of contemporary astronomical spectroscopy research. What is particularly interesting is obtaining indications of the existence of common formation environments of the matter of L and LL chondrites, possibly on a few primordial parent bodies. The statistical analyses indicate that there is no correlation between the concentration of principal chemical components and the petrographic type of ordinary chondrites. This proves homogenous distributions of these elements within the parent bodies of each group of ordinary chondrites. Hence, the distribution of these elements in individual present‐day asteroids is also homogenous.

AARS urzymes: Experimental biochemistry to map genetic coding

AARS urzymes: Experimental biochemistry to map genetic coding Dr Charlie Carter from the University of North Carolina at Chapel Hill explores how advances in enzymology and phylogenetics enable biochemical measurements that could map the ancestral development of genetic coding. Chemical reactions in the cell degrade energy-rich food molecules and rearrange their chemical bonds into other molecules necessary to construct and sustain living things far from chemical equilibrium. Those reactions occur spontaneously at rates that span an extraordinary range, the fastest going up to 1025 times faster than the slowest. (1) All these reactions must be accelerated by different amounts to maintain adequate concentrations of chemical components in the cell. Enzymes perform that differential acceleration exquisitely well.

Characteristics of ambient air quality and its air quality index (AQI) model in Shanghai, China

Long-term observations indicate that, the ambient air quality in Shanghai continues to improve, however the synergistic effects between the air pollutants PM2.5, O3 and NO2 are also increasing. The concentration of chemical components included in PM2.5 is higher in moderately polluted air containing multiple pollutants. This suggests that air pollution metrics based on multi-pollutant synergy are more descriptive of ambient air quality than single-pollutant air quality index (AQI) models that may ignore the effect of synergy between pollutants on ambient air quality forecasts. Therefore, this study proposes a new multi-pollutant air quality index model (NMAQI) based on four air pollutants (PM2.5, SO2, NO2 and O3) that emphasizes the relationship between PM2.5, NO2 and O3 in ambient air. The model successfully categorized observational data into classes of good, moderate, and polluted air quality ratings. Verification of the NMAQI model using the PM2.5 chemical composition spectrum shows that the NMAQI model can more accurately classify samples with high concentrations of chemical components (often misclassified by AQI) into high pollution levels. The model has an improved capacity to assess the degree of pollution in urban ambient air and to reduce the risk of public exposure to highly polluted atmospheric environments.

Influence of barrages on hydrological parameters and functional groups of phytoplankton of a subtropical river Ganga, India.

The current study used phytoplankton functional groups (FGs) to assess the impact of barrages on the ecological function of subtropical river Ganga. A total of 101 phytoplankton species were identified, including 20 phytoplankton FGs with MP and D having the highest prevalence rates of more than 50%. Other FGs with higher occurrence rates, such as N, A, and J, displayed seasonal and spatial advantages on occasion, indicating the randomness of exogenous influx from catchment areas. Based on phytoplankton FGs similarities, a non-metric multidimensional scaling analysis (NMDS) revealed geographical and seasonal discrepancies. The higher concentration of chemical components in Kanpur was linked to decreased water discharged from preceding reservoirs, resulting in a highly polluted stretch in terms of spatial variation, according to our findings. During the monsoon season, however, the diluting process caused by precipitation and surface runoff significantly improved water quality. As a result, we hypothesized that a sequence of barrages alters the hydrological characteristics of cascading reservoirs, which was related to spatial and seasonal fluctuation in FG diversity and phytoplankton FGs could be useful bioindicators of water quality. In conclusion, the phytoplankton FGs approach is useful for identifying the geographical and seasonal aspects of aquatic ecosystems that are heavily influenced by human activities, but its sensitivity to changes in spatial and seasonal water quality warrants more exploration.

Mineral medicinal groundwaters in Central Yakutia and prospects for their use

In this study, we reviewed and summarized the data on permafrost and groundwater areas of Central Yakutia to understand the formation and distribution of subpermafrost mineral waters of sodium bicarbonate and chloride-bicarbonate types, and to evaluate their potential use for medical purposes. Analysis of the data indicated that these low-mineralized groundwaters are basic analogues to the Maykop and Karachi mineral waters, with no particular bioactive components. These mineral water types contain 400 to 1200 mg/dm3 bicarbonates, 100 to 600 mg/dm3 chlorides, 50 to 250 mg/dm3 (Karachi) and &lt;50 mg/dm3 (Maykop) sulfates, 400 to 800 mg/dm3 sodium, and &lt;10 mg/dm3 calcium and magnesium. The formation of sodium bicarbonate and chloride-bicarbonate type water in Central Yakutia is influenced by permafrost which promotes concentration of major chemical components under the cold temperatures and slow groundwater circulation. The study of minor and trace constituents indicates that the subpermafrost waters in the study region contain fluorine and lithium in excess of the drinking water standards but are potentially appropriate for balneotherapy. Further research on the bio-physiological effects of subpermafrost waters with elevated fluorine and lithium concentrations contribute to the development of the spa and health resort industry in Yakutia. Moreover, the study will expand the balneological spectrum of disease prevention and treatment for the benefit of residents of Yakutia and the adjacent regions.

ღრმად განლაგებული სითხის გეოთერმული პირობები კოლხეთის არტეზიულ აუზში: წყლის ქიმიური შედგენილობა და გეოთერმომეტრია

Among the most important issues to be characterized is the temperature of the aquifer in any geothermal system. Fluids located deep within a hydrothermal system provide heat, and they control thermal groundwater temperature changes in aquifers. Geothermometers based on water chemistry have been used to estimate groundwater temperatures in various complexes. However, the average temperature measured by hydrochemical geothermometers is often variable, and it is difficult to assign a corresponding average geothermal fluid temperature because temperature and pressure change as the geothermal fluid moves upward. Different geothermometers cover different temperature ranges. Some hydrochemical geothermometers are suitable for high temperature geothermal systems, while others are suitable for medium and low temperature. Based on these geothermometers, it is difficult to assign a temperature that is close to the actual temperature of the geothermal system, because the influence of atmospheric precipitation, which causes a decrease in the concentration of chemical components and dilution due to mixing with shallow groundwater.

Identify nitrogen transport paths and sources contribution in karst valley depression area using isotopic approach

Karst groundwater provides drinking water for a quarter of Earth's population. However, in intensive agricultural regions worldwide, karst water is commonly polluted by nitrate (NO3−), particularly in the valley depression areas with well hydrological connectivity. The valley depression aquifers are particularly vulnerable to anthropogenic pollution because their pipes and sinkholes respond quickly to rainfall events and anthropogenic inputs. Identifying nitrate sources and transport paths in the valley depression areas is key to understanding the nitrogen cycle and effectively preventing and controlling NO3− pollution. This study collected high-resolution samples at four sites including one surface stream–SS, two sinkholes–SH and reservoir–Re, during the wet season in the headwater sub-catchment. The chemical component concentrations and stable isotopes (δ15N–NO3– and δ18O–NO3–) were analyzed. The stable isotope analysis model in R language (SIAR) was used to quantitatively analyze the contribution rate of NO3− sources. The results showed that the down section site (Re) has the highest [NO3−–N], followed by SH and the lowest SS. The sources calculation of SIAR demonstrated that, during the non-rainfall period, soil organic nitrogen was the primary source of the down section site, followed by fertilizer and the upper reaches sinkholes. During the rainfall period, fertilizer was the primary source of the down section site, followed by soil organic nitrogen and from upper reaches sinkholes. Rainfall events accelerated fertilizer–leaching into the groundwater. Slight denitrification may have occurred at the sampling sites but the assimilation of Re and SH could not occur. In conclusion, agricultural activities were still the primary influencing factor of [NO3−–N] in the study area. Therefore, the focus of NO3− prevention and control in the valley depression areas should consider the methods and timing of fertilization and the spatial distribution of sinkholes. To reduce nitrogen flux in the valley depression area, effective management policy should consider, e.g., prolongation of water residence time by wetland, and blocking nitrogen loss paths by sinkholes.

Interannual evolution of the chemical composition, sources and processes of PM2.5 in Chengdu, China: Insights from observations in four winters

The air quality in China has improved significantly in the last decade and, correspondingly, the characteristics of PM2.5 have also changed. We studied the interannual variation of PM2.5 in Chengdu, one of the most heavily polluted megacities in southwest China, during the most polluted season (winter). Our results show that the mass concentrations of PM2.5 decreased significantly year-by-year, from 195.8 ± 91.0 µg/m3 in winter 2016 to 96.1 ± 39.3 µg/m3 in winter 2020. The mass concentrations of organic matter (OM), SO42−, NH4+ and NO3− decreased by 49.6%, 57.1%, 49.7% and 28.7%, respectively. The differential reduction in the concentrations of chemical components increased the contributions from secondary organic carbon and NO3− and there was a larger contribution from mobile sources. The contribution of OM and NO3− not only increased with increasing levels of pollution, but also increased year-by-year at the same level of pollution. Four sources of PM2.5 were identified: combustion sources, vehicular emissions, dust and secondary aerosols. Secondary aerosols made the highest contribution and increased year-by-year, from 40.6% in winter 2016 to 46.3% in winter 2020. By contrast, the contribution from combustion sources decreased from 14.4% to 8.7%. Our results show the effectiveness of earlier pollution reduction policies and emphasizes that priority should be given to key pollutants (e.g., OM and NO3−) and sources (secondary aerosols and vehicular emissions) in future policies for the reduction of pollution in Chengdu during the winter months.

РОЛЬ ГИДРОТЕРМАЛЬНОЙ ДИНАМИКИ В ЗАРОЖДЕНИИ ЖИЗНИ НА ЗЕМЛЕ

In framework of the inversion concept one more required condition for the origin of life has been substantiated: multilevel fluctuations of physic-chemical parameters (in addition to the three accepted: availability of organic matter, aqueous medium, and source of energy). Taking this condition into consideration, hydrothermal systems were preferable medium for the origin of life on early Earth, in comparison with ocean. Hydrothermal environments are characterized by an extremely wide range of temperature, pressure, pH, and concentrations of components gradients. Multilevel fluctuations availability has been corroborated by means of thermodynamic estimations and direct measurements of pressure and temperature during the monitoring in some of the Kamchatka peninsula hydrothermal systems. The monitoring database mathematical processing reveals at least three levels of pressure fluctuations: 1) irregular macro fluctuations (with big amplitudes); 2) regular micro oscillations (with smaller amplitudes and periods about 20 minutes); 3) sudden pressure changes and fluctuations with periods lower than 5 minutes. High correlation between pressure, temperature, and concentrations of chemical components is also detected both in hydrothermal systems of Kamchatka and Slovenia. A lot of data on pressure and temperature dynamics in hydrothermal fluid, obtained by many researchers, can be applicable for investigation of the origin-of-life process.