Concentrations Of HCO3 Research Articles

Degradation of Carbamazepine in Water by UV-activated Sulfite Process

In this study, the degradation efficiency and mechanism of carbamazepine (CBZ), a typical emerging contaminant in water, in the UV/sulfite process were investigated. The effects of different concentrations of dissolved oxygen [ρ(DO)] on the degradation of CBZ by UV-activated sulfite were investigated. Additionally, under a simulated natural water environment-controlled initial ρ(DO) of (8.0 ±0.2) mg·L-1, the effects of different process parameters (sulfite dosages and reaction pH) and water environmental factors (the presence of HCO3-, Cl-, and humic acids) on the degradation of CBZ were comprehensively analyzed. The results showed that the UV/sulfite process efficiently degraded CBZ with a degradation rate of 85.3% during the 30 min reaction time and followed the pseudo-first order kinetic model with the constant of 0.055 7 min-1. Using the electron spin resonance detection, reactive species quenching tests, and the competition kinetics, the sulfate radicals (SO4-·) and hydroxyl radicals (·OH) in the UV/sulfite process were determined to be the main reactive species and were responsible for the degradation of CBZ with contribution rates of 43.9% and 56.1%, respectively. In addition, the degradation efficiency of CBZ decreased with the increasing concentration of HCO3-, and the presence of Cl- had little effect on the degradation of CBZ, whereas the presence of humic acids significantly inhibited the degradation of CBZ. Moreover, the accumulation of sulfate during the reaction was significantly lower than the limit of the Standard for Drinking Water (GB5749-2022). Additionally, the sulfite consumption rate constant was 0.004 4 min-1, which was significantly lower than the degradation rate constant of CBZ, indicating that sulfite could be activated efficiently by UV light to degrade CBZ in water.

Geochemistry of Geothermal Fluids in the Three Rivers Lateral Collision Zone in Northwest Yunnan, China: Relevance for Tectonic Structure and Seismic Activity

The Three Rivers Lateral Collision Zone (TRLCZ), situated at the southeastern margin of the Tibetan Plateau, is a crucial frontier where materials from the plateau flow southeastward. This study extensively investigated the hydrochemical characteristics and origin of helium and carbon isotopes in 73 thermal springs within the TRLCZ. The analysis revealed dominant processes, including carbonate and silicate interactions, resulting in elevated concentrations of HCO3− and Na+. The impact of Ca/Mg-rich minerals, particularly dolomite, influenced the cation composition. Additionally, gypsum dissolution, notably in the Lancangjiang Fault and Weixi–Qiaohou Fault, was highlighted through Ca/SO4 ratios. The positive correlation between SO42− and Cl− indicated dilution by shallow cold water, explaining the lower SO42− content in the Jingshajiang–Zhongdian Fault and Nujiang Fault compared to the Weixi–Qiaohou Fault and Lancangjiang Fault. The circulation depth of thermal spring water varied, with the northern Weixi–Qiaohou Fault exhibiting the shallowest circulation depth (~3 km), while the Jingshajiang–Zhongdian Fault and southern segments of the Nujiang Fault displayed deeper depths—ranging from 4 to 7 km. A positive correlation between the circulation depth and fault activity was also observed. The Rc/Ra ratios of free gas samples, predominantly indicating crustal origin, varied from 0.01 Ra to 0.53 Ra. Elevated Rc/Ra ratios in the research area suggested potential minor additions of mantle helium through faults and fractures. Crustal limestone was identified as the primary source of CO2-rich samples, with δ13CCO2 values ranging from −1.6‰ to −7.2‰, while trace amounts of mantle CO2 were found. The spatial distribution of the H2 concentration, CO2 concentration, He concentration, and mantle He proportions in gases indicated that higher values of He concentration and mantle He% always occur near sampling points with deeper circulation depths. However, no similar correlation was observed for H2 and CO2. Most earthquakes of magnitude 5 or greater occurred near the regions with high values of mantle source He release, highlighting the critical role of mantle fluids in the occurrence of earthquakes in the region. In this study, a fluid circulation model was developed to describe the process of fluid (water and gas) circulation migration and earthquake generation in the TRLCZ.

Comparison of chronic kidney disease progression and associated complications between geriatric and non-geriatric groups.

There is no consensus on the physiologic decline in estimated glomerular filtration rate (GFR) due to geriatric conditions related with the aging or chronic kidney disease (CKD) itself. In this study, we aimed to compare the CKD progression and associated complications in a large sample of geriatric and non-geriatric patients. The data of in 506 patients at age between 30 to 90 years and diagnosed with CKD at stage 2 and above (15 mL/min/1.73 m2 ≤ eGFR < 90 mL/min/1.73 m2) were collected retrospectively and compared among geriatric (>65 years old) and non-geriatric individuals. The rate of hypertension was higher in geriatrics compared to non-geriatrics (96.6% vs 91.9%, P = .04). Among laboratory findings, only PTH level was significantly lower and HCO3 concentration was higher in geriatrics compared to non-geriatrics (P = .02, P < .001, respectively). There was no significant difference in last measured eGFR (P = .99) while that measured 4 years ago was lower in geriatrics compared to that of non-geriatrics (P < .001). eGFR change was smaller in geriatrics compared to non-geriatrics (P < .001), and rate of progressive renal disease among non-geriatric group (39%) was found to be significantly higher than in the geriatrics (17.2%) (P < .001). The prevalence of hyperkalemia was lower in geriatrics at stage 3a (P = .02); prevalence of hyperparathyroidism was lower in those at stage 3b (P = .02) and lastly the acidosis was observed significantly lower in geriatric patients at stage 3a, 3b, and 4 compared to the non-geriatrics at corresponding stages (P < .001, P = .03, and P = .04, respectively). The eGFR change was significantly smaller in geriatrics at stage 3b and 4 (P < .001 and P = .04, respectively) while the rate of progressed renal disease was lower in geriatrics at stage 3a and 3b (21.1% vs 9.9%, P = .03 and 41.2% vs 11.1%, P < .001, respectively). eGFR change in 4-year period and the rates of progressive renal disease are higher in the non-geriatrics and also the prevalence of secondary complications of CKD, such as hyperparathyroidism, acidosis, and hyperkalemia, are higher in non-geriatrics. This may reflect that decline of GFR in geriatric individuals is at least partially related to physiological aging rather than kidney disease. Therefore, devising age related CKD definitions might be appropriate.

ТЕНДЕНЦИИ ИЗМЕНЕНИЯ ИОННОГО СОСТАВА ЛАДОЖСКОГО ОЗЕРА

The sum of ions of the basic Lake Ladoga water mass has varied quite significantly from 55.6 to 71.6 mg/L over the past 60 years. In the present paper, separate periods of the mineralization growth are identified. It is shown that the change in the mineralization of Lake Ladoga has been always accompanied by a significant change in the ratio of basic ion concentrations. Any significant trends in the total mineralization of Lake Ladoga over the analyzed period have not been identified, but periods of the growth and decrease in the number of ions have been revealed. Until 1998, the periods of increased mineralization, as a rule, were accompanied by an increase in concentrations of SO42 and Cl, most likely coming from the catchment area due to industrial and household pollution. During 2009-2019, the mineralization was growing mainly due to an increase in the absolute and relative concentrations of HCO3. At the same time, the concentration of dissolved CO2 in the main water mass of the lake also was increasing (and, consequently, pH was decreasing). Thus, the changes in the bicarbonate ion concentration in the water of Lake Ladoga may be largely determined by an increase in its inflow from the catchment area, whose possible reason is the enhancement of the chemical weathering of carbonate rocks due to the increasing concentrations of dissolved CO2 in the water.

The comparison of photocatalytic reduction of CO2 on ZnO photocatalysts at slightly acidic and alkaline pH towards the formation of valuable products

The photocatalytic reduction of CO2 to carbon monoxide, methane and hydrogen (as a valuable byproduct) in the suspension or solution of various Zn-based forms in an alkaline environment and water, respectively, was investigated. These are the first results showing homogeneous CO2 photoreduction in the presence of Zn-based photocatalysts in an inorganic environment.The ZnO photocatalysts were suspended in the alkaline environment, while in water, they completely dissolved during at least 6 hours of carbonation, forming a transparent solution. The small crystallite size also determines a high zinc solubility in an aqueous solution (97.7 % for 14 nm, 92.2 % for 25 nm, and 68.5 % for crystallites larger than 100 nm). This homogeneous solution showed a slightly lower photoactivity than the heterogeneous suspension because of a lower concentration of crucial bicarbonate HCO3- ions. In both cases, the selectivity gives the order H2>CO>CH4. It was suggested that the photoactive centres in the dissolved agglomerates are the –Zn–O–Zn– hydrous bridges, which can use bicarbonate (HCO3-) ions as a transporter of CO2. In addition, the H+ ions generated during the ZnO dissolving in water can first participate in the CO2 photoreduction towards CO and CH4 and, afterwards, involve forming small quantities of hydrogen.

The Hydrogeochemical Model of "YR" Geothermal Field, East Java

The YR Geothermal Field is located in East Java. This field is associated with an active volcano, implying a potential for a high enthalpy geothermal system. This field is still in the exploration phase, but no drilling has been conducted yet. Thus, insights into the geothermal system are obtained through geochemical analyses of geothermal manifestations. Geochemical analyses were performed on hot spring water samples to determine the characteristics, processes, origin, and fluid flow of the geothermal system. The research results indicate that the warm springs have temperatures ranging from 29.4 to 54.8°C, with a nearly neutral pH (6.14-6.44) and high contents of HCO3 (457-1150 mg/kg), Na (77.7-255 mg/kg), and Mg (37.4-110 mg/kg). Therefore, it can be concluded that all the warm springs fall into the bicarbonate type with immature conditions, indicating no direct association with the reservoir. The upflow zone is interpreted to be at the peak of Mount 7, while the outflow zones are in areas A, B, and C. The fluids flow from the upflow zone, then condense and advectively flow down the slope, experiencing dilution and reactions with rocks before emerging as outflows in the western and north-western areas.

Construction and Optimization of Corrosion Map in a Broad Region of Acidic Soil via Machine Learning

Machine learning has been widely applied to exploring the key affecting factors for metal corrosion in some local regions. However, there is a lack of systemic research and a practicable prediction model for metal corrosion in a broad region. In this paper, the corrosion map of Q235 steel in a broad region of acidic soils of Hunan province of Central China was constructed and optimized via field experiment and machine learning. Both the experimental and optimized corrosion maps confirmed that the corrosion rate of the steel decreased from the western to the eastern part of the province. The concentrations of pH, F−, Cl−, NO3−, HCO3−, K+, and Mg2+ were the key affecting factors in the broad region of acidic soils of the province. Among them, the contribution rate of the HCO3− concentration was higher than that of other factors. The optimization model based on the ordinary least squares could be used for the optimization of the corrosion map of steels in a broad region of acidic soils. The optimized corrosion map was a good alternative to the estimation methods for the corrosion rate of steel in soil.

Hybrid radical coupling during MnO2-mediated transformation of a mixture of organic UV filters: Chemistry and toxicity assessment

Manganese oxide (MnO2) is one of the most abundant metal oxides, and it is renowned for its ability to degrade various phenolic micropollutants. However, under MnO2-mediated transformation, BP-3 transforms into 12 different radical-coupled transformation products (TPs) out of 15 identified TPs. These radical-coupled TPs are reported with adverse environmental impacts. This study explored the effects of MnO2 on organic UV filter mixtures and different water constituents (i.e., bicarbonate ion (HCO3−), humic acid (HA) and halide ions) in terms of degradation efficiency and transformation chemistry. When a mixture of benzophenone-3 (BP-3) and avobenzone (AVO) underwent transformation by MnO2, hybrid radical-coupled TPs derived from both organic UV filters were generated. These hybrid radical-coupled TPs were evaluated by an in silico prediction tool and Vibrio fischeri bioluminescence inhibition assay (VFBIA). Results showed that these TPs were potentially toxic to aquatic organisms, even more so than their parent compounds. The higher the concentration of HCO3−, HA, chloride ion (Cl−) and bromide ion (Br−), the greater the reduction in the efficiencies of degrading BP-3 and AVO. Contrastingly, in the presence of iodide ion (I−), degradation efficiencies of BP-3 and AVO were enhanced; however, iodinated TPs and iodinated radical-coupled TPs were formed, with questionable toxicity. This study has revealed the environmental risks of hybrid radical-coupled TPs, iodinated TPs and iodinated radical-coupled TPs when the organic UV filters BP-3 and AVO are transformed by MnO2.

Optimization of K2CO3 exposure conditions using response surface methodology for CO2 capture with 2-methylpiperazine and monoethanolamine as promoters

In this study, the optimization of potassium carbonate (K2CO3) exposure conditions for CO2 capture with the use of 2-methypiperazine (2MPz) and monoethanolamine (MEA) as promoters was investigated. The tested operating conditions for the CO2 capture process included the pH, temperature, K2CO3 dose, gas flow rate, and pressure, and their effect on the CO2 absorption/desorption rate and CO2 absorption efficiency was assessed. Response surface methodology (RSM) was also employed to determine the equations for the optimal long-term operating conditions. The results showed that the CO2 absorption rate and efficiency increased under K2CO3 exposure with an increase in the pressure and loading rate. Moreover, for the temperature the absorption efficiency first increase and then decreases with increase in temperature, however, the with increase in temperature the faster absorption were observed with lower absorption loading rate. Furthermore, pH had a more complex effect due to its variable effects on the speciation of bicarbonate ions (HCO3−) and carbonate ions (CO32−). Under higher pH conditions, there was an increase in the concentration of HCO3−, which has a higher CO2 loading capacity than CO32−. Contouring maps were also used to visualize the effect of different exposure conditions on the CO2 absorption rate and efficiency and the role of 2MPz and MEA as promoters in the K2CO3 solution for CO2 absorption. The results showed that the mean CO2 absorption rate was 6.76 × 10−4 M/L/s with an R2 of 0.9693 for the K2CO3 solution containing 2MPz. The highest absorption rate (6.56–7.20 × 10−4 M/L/s) was observed at a temperature of 298–313 K, a pressure of >2 bar, a pH of 8–9, and a loading rate of 80–120 L/h for a concentration of 1–3 M K2CO3 and 0.05–1.5 M 2MPz. The CO2 absorption efficiency exhibited a variation of 56–70% under the same conditions.

Analysis of the Formation Mechanism of Hydrogen Sulfide in the 13# Coal Seam of Shaping Coal Mine.

In order to accurately predict the law of occurrence and migration of hydrogen sulfide (H2S) in the underground and effectively solve the problem of excessive concentration of H2S gas, laboratory experiments on the content of various forms of sulfur in coal, sulfur isotopes, thermal evolution history, and coal seam water samples were carried out by applying the theories of coal mine geology, microbiology, and analytical chemistry, and based on the experimental results, the cause of H2S gas was explored. Through the analysis of the geological conditions of the coal seam mined, it can be seen that the coal mine experienced the alternation of marine and continental phases in the process of coal formation and that there was no magma intrusion. The experimental results showed that iron sulfide in coal accounts for 73.25% of the total sulfur, indicating that the coal seam was rich in pyrite. The results of the isotope test showed that the sulfur isotopes in coal samples were all negative, indicating that the sulfur isotope fractionation in coal was large, the loss was serious, and the coal seam was greatly affected by seawater. According to the experimental results of vitrinite reflectance, it can be concluded that the highest temperature during the thermal evolution of the coal seam is 108.12 °C, which has not reached the temperature condition of sulfate thermochemical reduction. Comparing the concentration of acid ions in coal seam water and tap water, it was found that the concentration of SO42- in coal seam water is low, while the concentration of HCO3- is high. According to the experimental results and theoretical analysis, the H2S gas in the high-sulfur coal mine was caused by microbial sulfate reduction. Finally, the transformation path of sulfur in the coal seam was deduced and analyzed. The results showed that sulfur in coal is positively correlated with H2S gas concentration.

Direct potentiometric bicarbonate/carbon dioxide sensing based on polymeric membranes doped with selective meso-bisubstituted calix[4]pyrrole ionophores.

We evaluated in this work the properties of a promising class of HCO3- ionophores, which have not been recognized previously. Three types of neutral or charged calix[4]pyrroles with meso-bisubstituted groups were evaluated as ionophores for polymeric membrane HCO3- selective electrodes. Optimizing membrane components, such as ionophores, lipophilic additives and plasticizers, yielded ISEs exhibiting Nernstian response to HCO3- with improved linear range and detection limits, while the selectivity sequence differs significantly from the Hofmeister series. Interference from important biological and environmental species was reduced significantly, especially that from SCN-, NO3-, Br- and Cl-, which are always at high concentrations in related samples. In order to provide more insights into the properties of the ionophores and performance of the proposed ISEs, the stability constants of anion-ionophore complexes in the membrane phase were determined. Studies on the influence of the sample solution pH demonstrated that the proposed ISEs can be employed in a wide pH range of 3.0-9.0 with fast response (<30 s), good reversibility and long shelf life. Moreover, the proposed ISEs were used to quantify the concentration of HCO3- and dissolved CO2 in mineral and beverage samples with good recoveries.

Spatial variability and hydro/geochemical profiling of the elemental composition of mineral deposits and drip water from caves using unsupervised chemometric modelling

Caves are complex systems characterized by high variability in trace element signatures that simple geochemical analysis cannot detect since useful information hidden in the dataset may be lost. Sufficiently robust unsupervised statistical approaches may provide these significant signatures for cave hydro/geochemical profiling. The present study focused primarily on quantifying the relevant contributions of elements and their relationships to the variability of the hydro/geochemical profiles of speleothems, sediments and drip water within a cave using Principal Component Analysis (PCA) after Varimax rotation and two-way joining analysis as a clustering method. This prospective study was conducted on the Urșilor (Bears') show cave (Romania). The contents of Ca, Mg, Sr, Al, P, S, Fe and Zn in the mineral deposits were determined via X-ray fluorescence, while the content of these elements in drip water was determined via inductively coupled plasma–optical emission/mass spectrometry. The contents of HCO3−, Cl−, F−, NO3−, and SO42−; pH; electrical conductivity; and organic and inorganic carbon fractions were also determined. In the case of speleothems, the determinations were performed on randomly selected spots, reflecting the composition at various growth times. The PCA revealed that the geochemical profile of speleothems can be described by four principal components (PCs), represented by 71% for stalactites and 82/92% by three PCs for stalagmites/sediments. The strong signatures of Ca, Mg/Ca, K, and detrital elements (Al, Si, P, S) in stalagmites/sediments in proportions of 41/46%; K, Fe and Zn 30/32%; and Sr and Sr/Ca 11/15% were retained by PCA. The geochemical profile of the stalactites was described by Mg (35%), P, Zn, and Sr (21%); Al and Si (15%); and S, Ca and Mg/Ca (10%). Reducing the dimensionality of the data matrix to alkaline earth elements, two PCs described 95% of the mineral deposits, including the strong signatures of Mg/Ca and Sr/Ca, exceeding 50% of the variability in the first PC. Stalactites and stalagmites were primarily grouped based on their geochemical profile and less so on location, yielding two clusters/four subclusters of stalagmites. The PCA plot did not show a separation between stalactites and stalagmites, as their geochemical profiles differ significantly only in terms of Fe concentration. The hydrochemical profile of drip water was described by 4 PCs at a percentage of 95%: (i) alkaline elements, alkaline earth elements, anions and organic carbon and (ii) trace elements and DOC. The profile of Ca2+–HCO3− imprint drip water was described by two PCs at proportions of 66% (Ca, Mg, Na, K, Mg/Ca, Sr/Ca, Ba/Ca ratios, HCO3− and organic carbon) and 74% by trace elements (Co, Ni, Ti, Fe, Mn, V and Si). The transition trace elements have very complex chemical behaviour and appear in drip water as Ca-/Si-rich inorganic/organic colloids and simple ions. Although complementary to the PCA, the two-way joining analysis in a heatmap did not offer relevant information in the description of the hydro/geochemical profile of the karst system compared to PCA. A study of a farmed calcite sample highlighted its difference in composition compared with stalagmites in terms of Mg, Si, K, Zn, Sr and Sr/Ca. Future development could include the application of PCA to seasonally collected farmed calcite and drip water samples to obtain hydro/geochemical profiles of stalagmites in the making to determine the seasonal leaching of metals from bedrock/soil by drip water, inclusion in stalagmites, and seasonal growth. The practical significance of this paper for trace element research is of great concern because it allows these recorded indicators to be connected to the ancient climate and environment of stalagmites.

Formulation and Characterization of Instant Powder Combination of Ginger, Bangle, and Lemon Extract as an Antioxidant

Background: Degenerative disease is a decreasing organ function; clinical manifestations can affect the whole body, which is caused by oxidative stress. Ginger, bangle, and lemon have antioxidant properties. The combination of the three is expected to increase antioxidant activity. Objective: This study aimed to determine the potential antioxidant activity of the mixture of the three samples formulated as instant powder. Methods: This research is an experimental laboratory. This study will examine the effect of variations in extract concentration and PEG-40 HCO concentration on instant powder's characteristics and antioxidant activity. Results: Individually, ginger extract has extreme antioxidant activity (IC50 = 23.57 ± 0.13 µg/mL) and bangle strong (IC50 = 64.89 ± 0.15 µg/mL), while lemon has weak antioxidant activity (IC50 &gt;500 µg/mL). Combining ginger, bangle, and lemon with a simplex axial method obtained the combination of ginger: bangle: lemon with the ratio of 4/6: 1/6: 1/6. Adding a mixture of extracts affects the solubility and antioxidant activity of the extracts. The greater the amount of extract, the lower the solubility, and the antioxidant activity did not increase with addition. The addition of PEG-40 HCO increases the solubility of the extract in the instant powder. Antioxidant activity increased to the “medium” category (121.90 µg/mL) after adding PEG-40 HCO at a concentration of 2.70%. The unfavourable impact of PEG-40 HCO addition on instant powders is the angle of repose, flow time, and compressibility. Conclusion: The ginger, bangle, and lemon can be combined and made into instant powder with potential antioxidant activity in the moderate category.

Geochemical Characteristics and Productivity Evaluation of Water Produced from Coalbed Methane Wells in the Laochang Block, Eastern Yunnan.

The water produced from coalbed methane (CBM) wells contains abundant hydrogeochemical information, which is of great significance for the productivity evaluation of CBM wells. Based on the analysis of the conventional ions, hydrogen and oxygen isotopes, and trace elements in the water produced from three CBM wells in the Laochang Block, eastern Yunnan, the geochemical characteristics of the water produced from three CBM wells and their impacts on productivity are analyzed. The results show that the conventional ions in the water produced from all the three CBM wells in the study area exhibit similar characteristics, with low concentrations of Ca2+, Mg2+, SO42-, and F-, medium concentrations of K+, and high concentrations of Na+, Cl-, and HCO3-. As the drainage time increased, the water produced from wells S-2 and S-3 changed from the Na-Cl-HCO3 type to the Na-HCO3 type, while the water produced from well S-1 remained the Na-Cl-HCO3 type. The concentrations of HCO3- and F- are roughly positively correlated with the gas production, with higher gas production at concentrations of approximately 2000 and 2 mg/L, respectively. The gas production from well S-1 is relatively low, and it is speculated that this situation is caused by reservoir damage. The gas production from well S-2 is the lowest among the three wells in the study area, and it is speculated that the cause of this phenomenon is roughly due to breakage of the sandstone at the top of the coal seam or collapse of the wellbore, which communicates with the aquifer. Based on the characteristics of the water production from well S-3 with a good gas production, a quantitative characterization range of trace element changes in the water production from CBM wells is proposed. σY values of around 1500 μg/L and σM values of 0.4-0.5 μg/L are beneficial for the long-term gas production.

Carbonate content control in carbonate apatite coatings of biodegradable magnesium

Carbonate apatite (CAp) coating has been developed as a bioabsorbable corrosion-control coating for biodegradable Mg alloys. Carbonate content in the CAp coatings can be utilized to control the bioabsorbability and corrosion rate of CAp-coated Mg alloys. In this study, the carbonate content in the CAp coatings of pure Mg was varied by NaHCO3 concentration of the coating solution from 0.25 to 1.0 mol/L, and hydroxyapatite (HAp) was formed without NaHCO3. The CAp and HAp coatings were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The carbonate content in the apatite coatings formed with 0, 0.25, 0.5 and 1.0 mol/L NaHCO3 was determined to be 2, 12, 15 and 18 wt%, respectively, from the apatite 002 plane XRD peak position using the existing conversion constant as well as from the coating composition obtained by the XPS analysis. The values of carbonate content obtained by each method were in good accordance, indicating that the carbonate content can be determined simply by XRD measurements. Two types of carbonate group were present in the CAp coatings, CO32− and HCO3-, and the relative content of HCO3- to CO32− increased with an increase in the carbonate content.

Spatial distribution and enrichment mechanisms of high fluoride groundwater in geotherm-affected Pliocene aquifers of the Guide basin, China

Native high fluoride (F−) groundwater is one of the most serious environmental problems facing China and even the international society, which seriously threatens human health. The confined aquifer in the Guide basin contains high concentrations of F− and is subject to multifaceted influences, stemming not only from the geothermal activity present at the basin's bedrock but also from distinctive attributes such as elevated alkalinity, significant burial depths, and limited water circulation. Consequently, the precise mechanisms governing the enrichment of F− within the groundwater in this confined aquifer remain inadequately understood. This study aims to elucidate the migration and enrichment mechanism of F− in aquifers and assess the relative contributions of different control mechanisms responsible for high F− groundwater through systematic sampling, analysis and statistical calculations. Chemical types of confined groundwater and unconfined groundwater are Na-HCO3-Cl and Ca-HCO3, respectively. High-F− groundwater mainly exists in confined aquifers, and the content of F− gradually increases along the flow path. High content of HCO3− in confined groundwater promotes the precipitation of Ca2+, then enhances the dissolution of F−-containing minerals, resulting in F− being continuously released into groundwater. High pH, high Na/Ca molar ratios, geothermal and long residence time of groundwater are the additional factors to accelerate the release and migration of F− in groundwater. Results of redundancy analysis showed that competitive adsorption is the primary mechanism for F− enrichment in confined groundwater, followed by the geothermal effect, precipitation of carbonate minerals and residence time of groundwater time. The results of potential health risk assessment indicate that the potential health risks associated with confined groundwater are notably higher across all age groups compared to unconfined groundwater. The research results are not only helpful for the local government in reducing the threat of drinking-water fluorosis, but also provide a reference for other high-F− groundwater research with similar geological conditions in China and around the world.

PSVIII-30 Impaired Glucose-Stimulated Insulin Secretion in Intrauterine Growth-Restricted Neonatal Lambs Is Improved By Daily Supplementation of ω-3 Polyunsaturated Fatty Acid Ca2+ Salts

Abstract Maternofetal heat stress during placental development induces fetal intrauterine growth restriction (IUGR), which in turn reduces birthweight. IUGR-born livestock exhibit deficits in insulin stimulus-secretion coupling and glucose metabolism that contribute to poor growth efficiency. Thus, our objective was to determine whether daily oral supplementation of Ca2+ salts of ω-3 polyunsaturated fatty acids (ω-3 PUFA) to IUGR-born neonatal lambs improves glucose-stimulated insulin secretion and other indicators of metabolic efficiency. Maternal heat stress (40°C, 35% humidity, THI = 85) from d 40 to 95 of gestation was used to induce IUGR. Lambs were weaned at birth and hand-reared on milk replacer. Beginning at birth, lambs received daily oral boluses of 0.5 mL molasses containing 0 or 0.42 g/kg bodyweight of ω-3 PUFA (Virtus Nutrition). All lambs were fitted with femoral catheters at d 24 and a square-wave hyperglycemic clamp study was performed on d 28 to assess basal (i.e., resting) and glucose-stimulated insulin secretion (GSIS). Blood glucose concentrations did not differ among IUGR lambs (n = 8), IUGR+ω-3 lambs (n = 7), and controls (n = 12), but by study design were increased (P &amp;lt; 0.05) 205% from basal during hyperglycemic periods. Basal plasma insulin concentrations did not differ among groups, but basal glucose-to-insulin ratios were greater (P &amp;lt; 0.05) for IUGR+ω-3 lambs than for controls or IUGR lambs. During hyperglycemia, plasma insulin concentrations were 53% less (P &amp;lt; 0.05) for IUGR lambs but only 30% less (P &amp;lt; 0.05) for IUGR+ω-3 lambs compared with controls. Hyperglycemic glucose-to-insulin ratios were greater (P &amp;lt; 0.05) for IUGR lambs (3.24 ± 0.59) compared with controls (1.10 ± 0.29) and were intermediate for IUGR+ω-3 lambs (2.08 ± 0.86). Blood lactate concentrations did not differ among groups or between periods, but blood pH was was greater (P &amp;lt; 0.05) for IUGR (7.448 ± 0.006) and IUGR+ω-3 lambs (7.439 ± 0.003) compared with controls (7.422 ± 0.004). Blood partial pressure of CO2 was less (P &amp;lt; 0.05) for IUGR lambs (43.0 ± 0.3 mmHg) than for controls (46.7 ± 0.9 mmHg) and was intermediate for IUGR+ω-3 lambs (44.0 ± 0.4 mmHg). Blood HCO3 concentrations and O2-bound hemoglobin were greater (P &amp;lt; 0.05) for IUGR and IUGR+ω-3 lambs than for controls. Blood Na+ tended to be less (P = 0.07) and blood K+ was less (P &amp;lt; 0.05) for IUGR and IUGR+ω-3 lambs than for controls. Blood Ca2+ was less (P &amp;lt; 0.05) for IUGR lambs but not for IUGR+ω-3 lambs than for controls. These findings demonstrate that daily oral supplementation of Ca2+ salts of ω-3 PUFA improved deficits in insulin stimulus-secretion coupling and several other metabolic indicators observed in IUGR-born offspring. However, it did not improve all electrolyte concentrations or acid-base balance of the blood.

Study on coupling of typical elements in surface water and groundwater in the middle reaches of the Yangtze River, China

Understanding the coupling relationship of typical elements between surface water (SW) and groundwater (GW) is helpful to the prevention of regional water environment pollution. In this study, the coupling of typical elements (C, N, P) of SW and GW in the middle reaches of the Yangtze River was comprehensively analyzed using multiple statistics and hydrogeochemical modeling methods. SW chemical characteristics was found similar with that of GW in the middle reaches of the Yangtze River with cluster analysis, and all sampling points was divided into two principal components based on principal component analysis. One principal component was more affected by the water-carbonate mineral interaction, the other one was greatly affected by anthropogenic activities. More interestingly, no fixed replenishment and discharge relationship was found between SW and GW in different seasons, which laid a foundation for the coupling of typical elements between SW and GW. Cl- in SW and GW had the same major source. In addition, almost identical water-carbonate reactions was found occurred in phreatic water (PGW) and confined water (CGW). As a link between SW and CGW, PGW may accept the supplies of the two waters at the same time, resulting the concentrations of δD, Cl-, DOC and HCO3– in PGW ranking between SW and CGW. Furthermore, Nitrogen and phosphorus were found to migrate between SW and GW, and a potential ammonium source in shallow aquitard which generated a large amount of ammonium. The coupling effect of nitrogen source input and transformation occurred in the process of nitrogen coupling between SW and GW, which increased the ecological risk of water environment. This study provided a scientific basis for the control of SW-GW pollution in the middle reaches of the Yangtze River, and supported the security of the water ecological environment in the Yangtze River Basin.

Ion and Stable Isotope Geochemistry of Produced Water in Coalbed Methane Wells in the Tiefa Basin.

The potential geochemical information in the produced water of coalbed methane (CBM) wells is conducive to the exploration and development of CBM in the case that the produced water is primitive formation water. A total of 58 produced water samples collected from 13 CBM wells in the Daxing Mine, Tiefa Basin, were investigated. Ionic composition tests and stable isotope analysis were conducted to explore the geochemical characteristics and sources of produced water as well as the method for determining whether the produced water is primitive formation water. The results suggest that the fracking fluid for CBM stimulations is the main factor affecting the ion change of the produced water in the initial stage of drainage. The concentrations of Cl- and Ca2+ + Mg2+ could be taken as the indices to identify whether the produced water is primitive formation water. When the Cl- concentration is lower than 20 mEq/L and the Ca2+ + Mg2+ concentration is lower than 1 mEq/L, the produced water is close to the pristine formation water. Biogenic methanogenic activity may result in a high δ13CDIC and high concentrations of HCO3- in the pristine formation water in the Tiefa Basin. The data of δD and δ18O in the study area suggest that the formation water might come from atmospheric precipitation, which is later affected by evaporation and the water-rock reaction. The hydrogen isotope values in the produced water derived from the lower coal group display a substantial elevation compared to those from the upper coal group. This disparity in the hydrogen isotope composition presents an opportunity to utilize δD in produced water as a tool for distinguishing the formation water between these two groups.

Accumulated CO2 affects growth, acid-base regulation and ion balance of turbot (Scophthalmus maximus) in a recirculating aquaculture system

The major advantage of recirculating aquaculture systems (RAS) is the ability to manipulate and control environmental variables to optimize production efficiency. However, the characteristics of water recycling and high-density aquaculture in RAS may result in the rapid accumulation of carbon dioxide (CO2) when raising high-density marine fish. This study aimed to evaluate the effects of CO2 on growth-related parameters, tissue structure, acid-base homeostasis, and ion regulation in turbot (Scophthalmus maximus). Turbot were subjected to five different CO2 treatments (C, 8, 16, 24, and 32 mg/L) at a temperature of 14 °C for durations of 7, 15, 30, and 60 days. The results indicated a substantial reduction in specific growth rate with increasing duration of CO2 exposure, accompanied by a significant increase in feed conversion rate. Exposure to CO2 also triggered the deposition of lipids or glycogen in the turbot liver, inhibiting the expression of growth factors. Additionally, it caused dissolution of the intestinal lamina propria and vacuolation of the intestinal mucosa. Even exposure to low levels of CO2 (8 mg/L) caused damage to the turbot gill tissue. Plasma analysis of turbot showed significantly higher concentrations of plasma HCO3− and significantly lower concentrations of Na+ and Cl−. Plasma HCO3− concentrations reached a maximum of 33.35 ± 0.13 mmol/L in the 32 mg/L treatment, and genes related to osmoregulation and acid-base homeostasis in the gill (H+-ATPase, NBCI, CA, AE, NHE1, NHE2) were altered based on the duration of CO2 exposure. The kidney did not exhibit significant damage throughout the experiment, and genes related to renal osmoregulation and acid-base homeostasis (AE, NBCI, NHE3, CAII, CAIV) were significantly elevated with CO2 exposure compared to the control group. These findings indicate that prolonged exposure to CO2 has a severe impact on feeding, resulting in damage to the liver and intestinal tissues, stress within the fish body, and disrupted expression of key genes related to the growth hormone/insulin-like growth factor axis. The study highlights the significance of monitoring CO2 concentrations in RAS for optimal marine fish health, as even concentrations below the 8 mg/L threshold have an impact on turbot. The involvement of turbot kidneys strengthens their buffering capacity against CO2, but CO2 stress still affects the gut and growth axis due to ion exchange and the progression of the HCO3−buffering system, leading to growth inhibition. Overall, this study provides valuable insights into the effects of CO2 exposure on turbot aquaculture and underscores the importance of monitoring CO2 concentrations in RAS to ensure optimal health of marine fish.