Concentrations Of HCO3 Research Articles

Assessing groundwater quality in the northwestern coastal area of Sri Lanka using multivariate statistical techniques

The objective of the present study was to assess groundwater quality in the northwestern coastal region of Sri Lanka by analyzing hydrogeochemical data using multivariate techniques. The study examined the relationship between water quality and sources influencing groundwater quality and proposed useful statistical tools for water resource management. Descriptive, comparative, correlation, factor analysis (FA), and discriminant analysis (DA) were among the techniques used. The water quality in terms of electrical conductivity (EC), total dissolved solids (TDS), and dissolved nitrate and phosphate concentrations of the northwestern coastal area, where different aquifer conditions prevailed, were compared, and differences in the mean concentrations of the above parameters were identified. The study also employed ridge regression and support vector machines (SVM) to predict nitrate levels and validate the results using a 70:30 train/test split. The analysis found that the mean concentrations of EC, TDS, and HCO3- are higher in the sandy aquifer area, while Fe2+ and PO43- are higher in the regolith aquifer area. EC, TDS, PO43-, and HCO3- in the hard-rock aquifer area exceed permissible limits. Factor analysis identified four factors contributing to pollution, and a linear discriminant model classified all observations with 99.9% accuracy. The water quality index for Kalpitiya, Vanathavillu, and Katana-Negombo areas was 68.1, 99.2, and 287.9, respectively, while the World Health Organization (WHO) cutoff was 50. The use of multivariate statistical techniques demonstrated the value of analyzing hydrogeochemical data to gain valuable insights into the complex interplay of factors affecting groundwater quality. The SVM model, using a linear kernel, was identified as the best model to predict nitrate levels. A combination of statistical analyses reveals that, with the exclusion of a few wells, the groundwater in the study area is polluted and inappropriate for human consumption or culinary purposes. Nonetheless, the inhabitants persist in utilizing it as their primary source of drinking water. This study reveals the combination of statistical analyses is useful for the management of groundwater resources.

The Influence of Fluoride Ions on the Forms of Lanthanide Migration in Natural and Polluted Waters of the Lovozero Massif (The Kola Peninsula)

A comprehensive study (monitoring, thermodynamic modeling) of natural and anthropogenically polluted waters of the Lovozero Massif has been carried out. A thermodynamic study of the weathering of the Lovozero Massif within the “water-rock-atmosphere” system at a temperature of 5 °C showed that the elements contained in the rocks of the studied massif influence the formation of the chemical composition of natural waters. It has been established that an increase in the degree of “water-rock” interaction leads to an increase in the concentrations of F−, Cl−, SO42−, and HCO3− in the solution. This affects the mobility of lanthanum, cerium, and other elements due to the formation of complex compounds with them. The relatively high content of fluorine, phosphorus, and HCO3− (weak and medium acids) in the solution promotes the dissolution of silicates while Si, Al, and P are released into the solution. Monitoring of water from a flooded mine in which there is an increase in the degree of interaction of water with rock showed higher pH values for the concentrations of Na, HCO3−, F−, P, Al, Si, V, U, La, and Ce. The conclusions are relevant in the context of the use of groundwater for drinking water supply purposes. The obtained information is useful to evaluate the health of the population of the region under study.

The optimal dietary sodium and chloride level for broiler chicks fed a corn-soybean meal diet between 1 and 21 days of age.

The experiment was conducted to estimate the ideal dietary sodium (Na) and chloride (Cl) level for broilers during d 1 to 21 using a corn-soybean meal diet under a dietary Na:Cl ratio of 1:1. A total of 490 one-d-old Arbor Acres male broilers were randomly allotted by bodyweight to 1 of 7 treatments in a completely randomized design. Each treatment consisted of 7 replicate cages with 10 chicks per cage. Broilers were fed a Na and Cl-unsupplemented corn-soybean meal basal diet (control, containing 0.02% Na and 0.08% Cl) and the Na and Cl-supplemented basal diets containing 0.14%, 0.20%, 0.26%, 0.32%, 0.38% and 0.44% Na and Cl levels, respectively for 21 d. The results indicated that average daily gain, average daily feed intake, blood partial pressure of CO2 and concentrations of HCO3-, total CO2, Na+, Cl-, base excess and anion gap, tibial ash and ash Na contents of broilers were affected (P < 0.001) by dietary Na and Cl level, and increased linearly (P < 0.001) and quadratically (P < 0.001) with increasing Na and Cl levels. Feed/gain ratio, mortality, blood K+ concentration, serum osmotic pressure and K+, glucose and uric acid concentrations as well as heart, liver and kidney indices of broilers were affected (P < 0.01) by dietary Na and Cl level, and decreased linearly (P < 0.001) and quadratically (P < 0.001) with increasing Na and Cl levels. The estimates of dietary optimal Na and Cl levels were 0.07%-0.16% according to the best fitted broken-line or asymptotic models (P < 0.001) of the above sensitive indicators. Therefore, the optimal dietary Na and Cl level was suggested to be 0.16% to support all of the above Na and Cl metabolic requirements of broilers fed the corn-soybean meal diet during d 1 to 21, which is lower than the recommendation at 0.20% by the Chinese Feeding Standard of Chicken (2004).

Heterogeneous Activation of Persulfate by Petal-Shaped Co3O4@BiOI to Degrade Bisphenol AF

In catalytic tests, the results have shown that almost all the BPAF was removed within 30 min when the dosage of Co3O4@BiOI and sodium persulfate (PS) was 0.15 g and 0.1 mM, respectively. Acid conditions inhibited BPAF degradation, but the inclusion of a precise concentration of bicarbonate ions (HCO3−) promoted degradation. The presence of chloride (Cl−), sulfate ions (SO42−), and a high concentration of HCO3− inhibited the degradation process, whereas the addition of nitrate ions (NO3−) had a minor effect on the catalytic process. The presence of free radicals (sulfate (SO4•−), hydroxyl (•OH), and superoxide (O2•−)) and the non-free radical singlet oxygen (1O2) in the Co3O4@BiOI/PS system was determined by electron paramagnetic resonance (EPR) and quenching tests. We propose that the Co(II)/Co(III) and Bi(III)/Bi(V) redox pairs simultaneously activate PS where the Co3O4 and BiOI components work synergistically to promote the rapid oxidative degradation of BPAF in water.

Aluminium bioavailability and toxicity disrupted chloroplast structure and inhibited inorganic carbon utilization and nutrient uptake in Vallisneria natans at acidic and alkaline pH

Vallisneria natans, as submerged aquatic plants, face significant threats from aluminium (Al) toxicity. While the effects of Al at low pH on terrestrial plants have been extensively studied, there is a lack of research on the impacts of both low and high pH on chloroplast ultrastructure and nutrient uptake in submerged plants. This research is important as it aims to fill this gap by exposing the leaves of Vallisneria natans to 100 μM Al at varying pH levels (4.5, 5.5, 7.5, and 9.5) for 48 hours. The results showed that inorganic carbon (CT), CO2, and HCO3 content increased at extreme pH levels (4.5 and 9.5), suggesting decreased inorganic carbon utilization under Al stress. Additionally, photosystem II efficiency and electron transport rate were significantly reduced at extreme pH levels, highlighting the sensitivity of V. natans to Al. Chlorophyll a and total chlorophyll content were significantly lower at pH 4.5 compared to pH 7.5. Chloroplast structural disruptions were evident at extreme pH levels coupled with Al exposure, whereas minimal injury was observed at pH 5.5 and 7.5. The study also noted vacuole enlargement, altered plasma membrane permeability, and hematoxylin staining, indicating Al accumulation in leaves. ICP analysis revealed increased Al content at extreme pH levels, underscoring heightened Al bioavailability and toxicity. Significant reductions in macro and micronutrient content (P, Mg, K, Fe, Zn, B, Mn) were observed, likely due to Al-induced root and cell damage and altered nutrient uptake. These findings emphasize the complex interplay between Al exposure, pH fluctuations, and their cascading effects on the physiology and elemental composition of Vallisneria natans, highlighting the need for further research and environmental management strategies.

EARLY DIAGENESIS GEOCHEMISTRY OF BOTTOM SEDIMENTS IN THE PLEISTOCENE CORE OF LAKE KOTOKEL (Eastern Baikal Region)

Chemical composition of bottom sediments and pore waters of organic-mineral sediments (sapropel) of Lake Kotokel (Eastern Baikal region) has been studied, based on long drilling cores, 14.5 and 16.5 m. A reduction type of diagenesis has been established, during which destruction of organic matter, transformation of the chemical composition of pore waters and the formation of authigenic minerals occur. Even in the uppermost intervals of sapropel, organic matter is being profoundly transformed and differs significantly in composition from that of bioproducers (plankton). The major role in diagenetic transformations of organic matter belongs to different physiological groups of microorganisms, primarily heterotrophic, amonifying and sulfate-reducing bacteria. During diagenesis, the basic chemical composition of pore waters (HCO3–, SO42–, Cl–, Ca2+, Mg2+, K+, Na+) changes, trace elements (Fe, Mn, Sr, Ba, Pb, As, Co, Ni) redistribute, concentrations of HCO3–, NH4+, PO43− and Si increase; this is caused by destruction of organic matter. In the process of bacterial sulfate reduction in pore waters, the concentration of SO42– decreases along the depth of the section, and in the sediment the proportion of reduced forms of sulfur increases and the isotopic composition of sulphur δ34S changes. Transformation of chemical composition of pore waters and the activity of microorganisms leads to the formation of authigenic pyrite, rhodochrosite, and barite.

Biomarker screening for pulmonary hypertension in VLBW infants at risk for bronchopulmonary dysplasia.

Very low birth weight (VLBW) infants demonstrate altered alveolar and pulmonary vascular development and carry an increased risk of developing bronchopulmonary dysplasia (BPD) and pulmonary hypertension (PH). Risk stratification for BPD-associated PH (BPD-PH) in at-risk infants may help tailor management, improve outcomes, and optimize resource utilization. VLBW infants were screened for PH with blood gas measurements, serum NT-proBNP and bicarbonate (HCO3) levels, and echocardiograms if they remained on respiratory support at 34 weeks corrected gestational age. We then tested 11 models using different cutoffs for NT-proBNP and HCO3 to predict infants at low risk of BPD-PH. We identified PH in 34 of 192 (17.6%) VLBW infants. The median NT-proBNP in VLBWs with PH was 2769 pg/mL versus 917 pg/mL in those without PH (p < 0.0001). A model with NT-proBNP < 950 pg/mL and HCO3 < 32 mmol/L had a sensitivity of 100%, specificity of 34.2%, and negative predictive value of 100%. Using this model, 54 of 192 (28%) of the patients in this study would have been categorized as low risk for PH and could have avoided a screening echocardiogram. NT-proBNP and HCO3 together may serve as sensitive and cost-effective screening tools for BPD-PH in VLBW infants. NT-proBNP and HCO3 concentrations obtained together may help identify very low birth weight infants at risk for bronchopulmonary dysplasia who should undergo screening for pulmonary hypertension with echocardiography. This large dataset demonstrates that NT-proBNP and HCO3 levels together are more sensitive than NT-proBNP alone in identifying VLBW infants to undergo echocardiography. The combination of NT-proBNP and HCO3 levels may identify VLBW infants at low risk for pulmonary hypertension and thus those who may be able to avoid screening echocardiography.

Effect and mechanism of steel slag composition on CO2 fixation rate under microbial and non-microbial

In this study, we used microorganisms and steel slag to reduce CO2 emissions. The main objective is to investigate the influence and mechanisms of CO2 fixation rate based on the composition of steel slag. In the absence of microorganisms, steel slag powders with higher C2S content exhibit higher CO2 fixation rate. The absolute content of C2S decreases by 2.16–5.86 % and 3.43–14.21 % at 2 h and 48 h of carbon sequestration reaction, respectively. Under the action of microorganisms, the CO2 fixation rate of different steel slags increases by more than two-fold, with increases in amount of CO2 fixation at 2 h and 48 h of reaction being 142–169 % and 166–191 %, respectively. Microorganisms can enhance the reaction degree of C2S, C3S, and C2F phases in different steel slags. The increase in amount of CO2 fixation is particularly significant for steel slag powders with high C2S and C2F content. Enzymes secreted by microorganisms in the early stage of carbon sequestration can also increase the concentration of HCO3- and CO32- in the liquid phase, but this is influenced by the pH value and Ca2+ concentration of different steel slag leachates. Steel slag powders with lower leachate pH values and containing small amounts of Ca2+ will be more conducive to microorganisms enhancing the early-stage CO2 fixation rate.

Evaluating hydrogen ion mobilization during hemodialysis using only predialysis and postdialysis blood bicarbonate concentrations.

The hydrogen ion (H+) mobilization model has been previously shown to provide a quantitative description of intradialytic changes in blood bicarbonate (HCO3) concentration during hemodialysis (HD). The current study evaluated the accuracy of different methods for estimating the H+ mobilization parameter (Hm) from this model. The study compared estimates of the H+ mobilization parameter using predialysis, hourly during the HD treatment, and postdialysis blood HCO3 concentrations (Hm-full2) with those determined using only predialysis and postdialysis blood HCO3 concentrations assuming steady state conditions (Hm-SS2) during the midweek treatment in 24 chronic HD patients treated thrice weekly. Estimated Hm-full2 values (0.163 ± 0.079 L/min [mean ± standard deviation]) were higher than, but not statistically different (p = 0.067) from, those of Hm-SS2 (0.152 ± 0.065 L/min); the values of Hm-full2 and Hm-SS2 were highly correlated with a correlation coefficient of 0.948 and a mean difference that was small (0.011 L/min). Further, the H+ mobilization parameter values calculated using only predialysis and postdialysis blood HCO3 concentrations during the first and third HD treatments of the week were not different from those calculated during the midweek treatment. The H+ mobilization model can be used to provide estimates of the H+ mobilization parameter without the need to measure hourly intradialytic blood HCO3 concentrations.

Enhanced silicate weathering accelerates forest carbon sequestration by stimulating the soil mineral carbon pump.

Enhanced silicate rock weathering (ERW) is an emerging strategy for carbon dioxide removal (CDR) from the atmosphere to mitigate anthropogenic climate change. ERW aims at promoting soil inorganic carbon sequestration by accelerating geochemical weathering processes. Theoretically, ERW may also impact soil organic carbon (SOC), the largest carbon pool in terrestrial ecosystems, but experimental evidence for this is largely lacking. Here, we conducted a 2-year field experiment in tropical rubber plantations in the southeast of China to evaluate the effects of wollastonite powder additions (0, 0.25, and 0.5 kg m-2) on both soil organic and inorganic carbon at 0-10 cm depth. We found that ERW significantly increased the concentration of SOC and HCO3 -, but the increases in SOC were four and eight times higher than that of HCO3 - with low- and high-level wollastonite applications. ERW had positive effects on the accrual of organic carbon in mineral-associated organic matter (MAOM) and macroaggregate fractions, but not on particulate organic matter. Path analysis suggested that ERW increased MAOM mainly by increasing the release of Ca, Si, and Fe, and to a lesser extent by stimulating root growth and microbial-derived carbon inputs. Our study indicates that ERW with wollastonite can promote SOC sequestration in stable MOAM in surface soils through both the soil mineral carbon pump and microbial carbon pump. These effects may have been larger than the inorganic CDR during our experiment. We argue it is essential to account for the responses of SOC in the assessments of CDR by ERW.

A potential CO2 carrier to improve the utilization of HCO3– by plant-soil ecosystem for carbon sink enhancement

IntroductionImproving the rhizospheric HCO3– utilization of plant-soil ecosystem could increase the carbon sink effect of terrestrial ecosystem. However, to avoid its physiological stress on the crop growth, the dosage of HCO3– allowed to add into the rhizosphere soil was always low (i.e., <5–20 mol/m3). ObjectivesTo facilitate the utilization of relatively high concentrations of HCO3– by plants in the pursuit of achieving terrestrial carbon sink enhancement. MethodsIn this study, the feasibility of directly supplementing a high concentration HCO3– carried by the biogas slurry to the plant rhizosphere was investigated using the tomato as a model plant. ResultsThe CO2-rich biogas slurry was verified as a potential CO2 carrier to increase the rhizospheric HCO3– concentration to 36 mol/m3 without causing a physiological stress. About 88.3 % of HCO3– carried by biogas slurry was successfully fixed by tomato-soil ecosystem, in which 43.8 % of HCO3– was assimilated by tomato roots for the metabolism, 0.5 ‰ of HCO3– was used by microorganisms for substances synthesis of cell structure through dark fixation, and 44.4 % of HCO3– was retained in the soil. The rest of HCO3– (∼11.7 %) might escape into the atmosphere through the reaction with H+. Correspondingly, the carbon fixation of tomato-soil ecosystem increased by 150.1 g-CO2/m2-soil during a tomato growth cycle. As for the global countries that would adopt the strategy proposed in this study to cultivate the tomato, an extra carbon sink of soil with about 1031.1 kt-C per year (i.e., an additional 0.21 tons of carbon per hectare soil) could be obtained. ConclusionThis would be consistent with the goal of soil carbon sink enhancement launched at COP21. Furthermore, the regions with low GDP per capita may easily achieve a high reduction potential of CO2 emissions from the agricultural land after adopting the irrigation of CO2-rich biogas slurry.

A Study on Impact of Agricultural Activities on the Groundwater Quality of Medchal Malkajgiri District, Telangana State, India

The main aim of the present study is to evaluate the impact of agricultural activities on the groundwater quality in the eleven selected village areas of Medchal-Malkajgiri district of Telangana State, India. Forty Groundwater samples were collected during pre-monsoon and post-monsoon. The groundwater samples collected were analyzed for key agricultural nutrients, including Nitrates (NO₃⁻), Phosphates (PO₄³⁻), and Potassium (K⁺), as well as various physico-chemical parameters such as pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Total Hardness (TH), Total Alkalinity (TA), Sodium (Na⁺), Calcium (Ca²⁺), Magnesium (Mg²⁺), Carbonates (CO₃²⁻), Bicarbonates (HCO₃⁻), Chloride (Cl⁻), Fluoride (F⁻), and Sulphates (SO₄²⁻). The analyses followed the American Public Health Association (APHA) Standard Methods for the Examination of Water and Wastewater. The results were then compared against the Bureau of Indian Standards (BIS) 2012 and World Health Organization (WHO) 1999 guidelines for drinking water quality. The analytical results reveal that nitrates are within the acceptable limit during pre-monsoon season but five samples (25%) were exceeding the acceptable limits in post-monsoon season. It clearly indicates that the agricultural activities may be affecting the quality of groundwater in the study area. The concentration of TDS, TA, HCO3– and Cl– are also showing higher values.

PH Homeodynamics and Male Fertility: A Coordinated Regulation of Acid-Based Balance during Sperm Journey to Fertilization.

pH homeostasis is crucial for spermatogenesis, sperm maturation, sperm physiological function, and fertilization in mammals. HCO3- and H+ are the most significant factors involved in regulating pH homeostasis in the male reproductive system. Multiple pH-regulating transporters and ion channels localize in the testis, epididymis, and spermatozoa, such as HCO3- transporters (solute carrier family 4 and solute carrier family 26 transporters), carbonic anhydrases, and H+-transport channels and enzymes (e.g., Na+-H+ exchangers, monocarboxylate transporters, H+-ATPases, and voltage-gated proton channels). Hormone-mediated signals impose an influence on the production of some HCO3- or H+ transporters, such as NBCe1, SLC4A2, MCT4, etc. Additionally, ion channels including sperm-specific cationic channels for Ca2+ (CatSper) and K+ (SLO3) are directly or indirectly regulated by pH, exerting specific actions on spermatozoa. The slightly alkaline testicular pH is conducive to spermatogenesis, whereas the epididymis's low HCO3- concentration and acidic lumen are favorable for sperm maturation and storage. Spermatozoa pH increases substantially after being fused with seminal fluid to enhance motility. In the female reproductive tract, sperm are subjected to increasing concentrations of HCO3- in the uterine and fallopian tube, causing a rise in the intracellular pH (pHi) of spermatozoa, leading to hyperpolarization of sperm plasma membranes, capacitation, hyperactivation, acrosome reaction, and ultimately fertilization. The physiological regulation initiated by SLC26A3, SLC26A8, NHA1, sNHE, and CFTR localized in sperm is proven for certain to be involved in male fertility. This review intends to present the key factors and characteristics of pHi regulation in the testes, efferent duct, epididymis, seminal fluid, and female reproductive tract, as well as the associated mechanisms during the sperm journey to fertilization, proposing insights into outstanding subjects and future research trends.

Co-occurring characteristics and mechanisms of geogenic ammonium and phosphorus in Quaternary alluvial-lacustrine aquifer systems

High loads of nitrogen (N) and phosphorus (P) in groundwater are a pressing global environmental concern. Geogenic ammonium (NH4+) and P anomalies in groundwater as unique forms of contamination, have been extensively reported. However, despite significant efforts on the enrichment of geogenic NH4+ or P, little is known about their co-occurring characteristics and mechanisms in groundwater. Therefore, focusing on the Dongting Plain (DTP) within the central Yangtze River basin, a typical alluvial-lacustrine plain, this study analyzed hydrogeochemistry, stable carbon isotopes, and dissolved organic matter (DOM) fluorescence. The results revealed a clear correlation between the groundwater DOM humification degree and the redox processes. In different redox processes, four distinct groundwater types emerged sequentially: low-NH4+ & low-P, low-NH4+ & high-P, high-NH4+ & high-P, and high-NH4+ & low-P. In organic matter (OM) degradation process, when dissolved oxygen and nitrate acted as electron acceptors, the low-NH4+ & low-P groundwater dominated. The low-NH4+ & high-P groundwater dominated when Mn(IV) and amorphous Fe(III) (oxyhydr)oxides served as the electron acceptors, where P enrichment was primarily attributed to the reductive dissolution of amorphous Fe(III) (oxyhydr)oxides. The high-NH4+ & high-P groundwater dominated when SO42-, crystalline Fe(III) (oxyhydr)oxides, and CO2 served as the electron acceptors. During this phase, OM mineralization resulted in the enrichment of both NH4+ and P. Furthermore, the reductive dissolution of crystalline Fe(III) (oxyhydr)oxides further increased P concentrations in groundwater. During the strong degradation of OM to the methanogenic stage, two processes occurred simultaneously: anaerobic oxidation of methane and reductive dissolution of Fe(III) (oxyhydr)oxides. These processes led to an increase in the concentration of HCO3– and Fe(II) in groundwater. During this phase, large amounts of HCO3– and Fe(II) combine to form siderite precipitates. These precipitates adsorb P from the groundwater, eventually leading to a decrease in P concentration and the formation of high-NH4+ & low-P groundwater. This study offers novel insights into the simultaneous cycling of N and P in Quaternary alluvial-lacustrine aquifer systems.

Evaluating forward osmosis performance of MEA/MDEA absorbents for water replenishment in post-combustion carbon capture

The large-scale deployment of post-combustion carbon capture exerted additional pressure on water resources. In this work, the feasibility of forward osmosis driven by unloaded or CO2 loaded Monoethanolamine (MEA), N-Methyldiethanolamine (MDEA) and their blended absorbents for water replenishment was investigated. The results indicated that the water flux of unloaded MDEA solution increased from 12.92 LMH to 18.72 LMH at amine concentrations from 1 M to 5 M, which was much higher than that of unloaded MEA solution, owing to the huge differences of the osmotic pressure. As the MEA and the MDEA were blended, some synergistic effects may work to result in the higher osmotic pressures and the lower water fluxes of MEA-MDEA blended solutions than the summation of the individual ones, respectively. Furthermore, as the CO2 was absorbed by the MEA-MDEA blended solution, the water fluxes of the CO2 loaded solutions increased nonlinearly. Specifically, when the CO2 loading was lower than a specific critical value, the growth of the water fluxes of MEA-MDEA blended solutions with the CO2 loading gradually slowed down, caused by the increase of the solute diffusion resistivity. However, when the CO2 loading exceeded the critical value, the water fluxes of blended solutions become increasing faster with the CO2 loading, probably due to the increase of the concentration of HCO3– and MEAH+. On the other hand, there was an optimal CO2 loading value that minimized the reverse solute flux.

Interactive effects of urine components and treatment conditions on antibiotic degradation of combined system integrating thermally activated peroxydisulfate and membrane distillation using machine learning

The antibiotic degradation in urine is gaining focus as it’s essential for resource recovery. Complex organic and inorganic substances in urine impact degradation efficiency through their involvement in radical-type chain reactions. In this study, more than 95 % of sulfamethoxazole (SMX) in urine was successfully degraded in both concurrent and sequential modes of a combined system integrating thermally activated peroxydisulfate and membrane distillation (TAP-MD), previously shown to be effective for resource recovery. Three algorithms, including random forest (RF), XGBoost, and support vector machine (SVM), were applied to model the impact of urine components and treatment conditions on SMX degradation. The XGBoot and RF models, fine-tuned by Bayesian optimization, are accurate and credible in both prediction and interpretation (R2 > 0.90). The models suggest that the improvement of SMX degradation by the MD process is due to PDS enrichment, with high PDS concentrations significantly promoting SMX degradation. Urea and HCO3− are the key factors impacting SMX degradation efficiency, followed by temperature, PDS, Cl−, and NH4+. Additionally, strong interaction effects between urine components were found on SMX degradation, contrasting with results from individual ions that were present in isolation. At high urea concentration (>100 mM), increasing concentrations of Cl−, NH4+, and HCO3− significantly inhibited SMX degradation. As the second key factor on SMX degradation, HCO3− can react with S2O82− without producing free radicals, resulting in a reduction in its yield. Furthermore, in the presence of high concentrations of HCO3−, the Cl− and NH4+ negatively affect the kobs of SMX degradation. The HCO3− competes with SMX for Cl to produce the weak oxidant CO3∙−, which reacts quickly with NH2∙ without producing other free radicals, causing a loss of free radicals.

Novel insights into ferrate (VI) activation by Mn-modified sludge biochar for sulfamethoxazole degradation: Dominance of hydroxyl group and Mn-O bond in the non-radical pathway

Ferrate (Fe (VI)), as a versatile oxidizer, has been widely employed for water treatment. However, the rapid self-decomposition of Fe (VI) diminishes its practical application efficiency. In this study, a novel Mn-modified sludge biochar (MSBC) was synthesized for the first time to activate Fe (VI) and generate highly reactive Fe (IV)/Fe (V) for the rapid removal of sulfamethoxazole (SMX). The results showed that MSBC (0.10 g/L) effectively activated Fe (VI) (100 μM), and 87.39 % of SMX (10 μM) and 40.26 % of total organic carbon (TOC) were removed within 10 min. Notably, raising the solution pH (e.g., from 6.0 to 11.0) would result in decreasing the reactivity of Fe (VI) and a lower removal efficiency of SMX. The quenching, electron paramagnetic resonance and probe experiments suggested that •O2– and high-valent iron species (Fe (V)/Fe (IV)) were identified as the major contributions to the removal of SMX. The detailed activation sites of MSBC were –OH and Mn-O, as corroborated by density functional theory (DFT) calculation and characterization. These activation sites facilitated activation of Fe (VI) through efficient electron transfer. The Fukui index indicated that the N, S, and O atom of SMX were the primary attacked sites. Subsequently, five potential degradation pathways were proposed, with the cleavage of the S-N bond being the predominant one. The toxicity of these products was examined using ECOSAR program, revealing that main products showed low toxicity or non-toxicity. The Cl-, SO42-, and NO3– had negligible effect on SMX degradation, although excessive concentrations of HCO3– and humic acid (HA) showed slightly inhibition. Additionally, the Fe (VI)/MSBC system also effectively removed 87.34 % of sulfadiazine (SDZ) and 93.91 % of sulfamethoxypyridazine (SMP). Overall, this study offered a practical and cost-effective approach for the activation of Fe (VI) and provided new insights to the degradation mechanism.

A bicarbonate-rich liquid condensed phase in non-saturated solutions in the absence of divalent cations.

Bicarbonate (HCO3 -) and sodium (Na+)-containing solutions contain droplets of a separate, bicarbonate-rich liquid condensed phase (LCP) that have higher concentrations of HCO3 - relative to the bulk solution in which they reside. The existence and composition of the LCP droplets has been investigated by nanoparticle tracking analysis, nuclear magnetic resonance spectroscopy, refractive index measurements and X-ray pair distribution function analysis. The bicarbonate-rich LCP species is a previously unaccounted-for, ionic phenomenon which occurs even in solutions with solely monovalent cations. Its existence requires re-evaluation of models used to describe and model aqueous solution physicochemistry, especially those used to describe and model carbonate mineral formation.

Exploring the cause of reduced production responses to feeding corn dried distillers grains in lactating dairy cows

An experiment was conducted to identify the factors that cause reduced production of cows fed a diet with high content of corn distillers grains with solubles (DDGS). We hypothesized that the factors could be high sulfur (S) content in DDGS, which may directly (S toxicity) or indirectly (DCAD) cause reduced production. We also hypothesized that high PUFA in DDGS could be another major factor. In a randomized complete block design, 60 lactating cows (15 primiparous and 45 multiparous; average ± SD at the beginning of the trial: milk yield, 44.0 ± 6.9 kg/d; DIM, 123 ± 50; BW, 672 ± 82 kg) were blocked, and cows in each block were randomly assigned to 1 of the following treatments: SBM (4.7% fatty acids [FA], 0.22% S, and 178 mEq/kg DM of DCAD), a diet containing soybean meal as the main protein source; DG, with SBM replacing mainly soybean byproducts and supplemental fat with distillers grains at 30% dietary DM (4.7% FA, 0.44% S, and 42 mEq/kg DM of DCAD); SBM+S, SBM with sodium bisulfate for additional dietary S (4.8% FA, 0.37% S, and 198 mEq/kg DM of DCAD); SBM+CO, SBM with corn oil (4.7% FA, 0.23%, and 165 mEq/kg DM of DCAD); and DG+DCAD, DG with increased DCAD (4.7% FA, 0.40% S, and 330 mEq/kg DM of DCAD). Due to the limited number of tiestalls, blocks 1 to 6 started the experiment first as phase 1, and the rest of the blocks, as phase 2, started the experiment after phase 1. All cows were fed the SBM diet for 10 d as a covariate period followed by the experimental period for 35 d. Data were analyzed using PROC MIXED of SAS (Version 9.4, SAS Institute Inc.); block and phase were random effects; and treatments, repeated week, and interaction were fixed effects. We found an interaction of week by treatment for DMI. Although milk yield did not change, milk fat concentration tended to decrease (2.78% vs. 3.34%) for DG compared with SBM. Dry matter, OM, NDF, and CP digestibilities were lower when cows were fed the DG diet compared with SBM. Additionally, cows fed DG had lower blood concentrations of HCO3-, base excess, and total (t)CO2 compared with SBM. The SBM+S diet did not affect production, nutrient digestibility, or blood parameters compared with SBM. The SBM+CO diet decreased milk fat concentration and yield compared with SBM. The DG+DCAD diet tended to increase milk fat yield and concentration (1.24 vs. 1.47 kg/d; 2.78% vs. 3.37%) and increased ECM (40.9 vs. 45.1 kg/d) compared with DG but did not improve nutrient digestibility. However, blood HCO3-, base excess, and tCO2 were greater for DG+DCAD compared with DG. In conclusion, the indirect role of S-, altering DCAD, along with the high PUFA content in DDGS, appear to be the factors causing reduced production responses to a high DDGS diet. Increasing DCAD to 300 mEq/kg DM in a high DDGS diet can be a feeding strategy to alleviate reduced production responses.

Characterization of groundwater potability and irrigation potential in Uttar Pradesh, India using water quality index and multivariate statistics

Abstract This study includes groundwater quality data from 290 monitoring sites from 69 districts of Uttar Pradesh, India. The analysis of the data showed that 1.3, 75.52, 47.93, and 31.03% of groundwater samples had concentrations of electrical conductivity (EC), total hardness (TH), Mg2+, and HCO3−, respectively, higher than the maximum permissible limit. Groundwater quality index (GWQI) was calculated for these 290 monitoring sites which revealed that 21 sites (7.24%) had inappropriate GWQI for drinking water, and 18 sites (7.24%) had an unsuitable index for irrigation. Most of the sampling sites (98.97%) showed high EC contents in groundwater with a mean value of 999.33 μS/cm. Fluoride content was found within the permissible limits in 95.52% of the samples, while 4.48% had high concentrations. The use of hierarchical cluster analysis differentiated all the sites into two clusters: one with high pollution and the other with low pollution. Significant correlations exist between physicochemical and irrigation indicators in the correlation matrix. High loadings of EC, TH, Ca2+, Mg2+, Na+, Cl−, and SO42− were identified in the first principal component, which are thought to be pollution-controlled processes from anthropogenic sources. According to the Chadha diagram, CaHCO3 and Ca–Mg–HCl were the two most prevalent chemicals in the water.