Concentrations Of HCO3 Research Articles

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.

Nghiên cứu phân hủy pentaclophenol trong nước bằng hệ oxy hóa percarbonic acid

In this work, the degradation of a persistent organic pollutant, pentachlorophenol (PCP) by a green oxydation system based on peroxymonocarbonate (HCO4-) was studied. Different factors including pH, HCO3- concentration, metal ion catalyst, temperature, and UV irradiation were investigated for their effects on PCP degradation. The results showed that among five tested metal ions (Co2+, Ni2+, Fe2+, Cu2+, Mn2+), Co2+ gave the best catalytic activity. The optimum degradation of PCP was obtained at the concentration of HCO3- and H2O2 of 10 mM and 25 mM, respectively, catalyzed by the presence of 0.1 mg/L Co2+ ion at the intrinsic pH value of the system (8÷10). Moreover, UV irradiation remarkably enhanced the radical formation in the oxydation system, which led to higher degradation efficiencies. The results of COD and TOC removal and LC/MS/LS analysis clearly revealed the potential of complete mineralization of PCP by the oxydation system H2O2/HCO3-/Co2+/UV.

Geochemical characteristics of natural springs within the Lenglongling fault zone related to the Menyuan Ms 6.9 earthquake on January 8, 2022, NW China

Geofluids from natural springs connect with the crust and/or mantle in many cases, and their geochemical anomalies could be significant for the study on faults activity and even earthquakes. Several natural springs are distributed along the Lenglongling fault zone (LLLFZ) in the northeastern margin of the Tibetan Plateau, where the Ms 6.9 Menyuan earthquake occurred on January 8th, 2022. Based on chemical and isotopic compositions (δD, δ18O, δ13C, and 3He/4He) of water and gas samples, the origin of geofluids and their potential correlation with fault activity even including earthquakes are preliminarily assessed in this paper. The δ13CCO2 values and 3He/4He ratios showed that the gas originating from the crust was associated with the metamorphism of carbonate rocks, whereas the δ18O and δD values of water samples indicated that the natural springs were predominantly infiltrated with precipitations from local mountains ranging 3.7 - 5.5 km in height. Obvious changes of Ca2+ and HCO3− concentrations in SZK spring waters in the surface rupture zones were observed in a short period (about three months) after the main shock, in contrast to those of the GSK springs far from the surface rupture zones. Such variations might be correlated with the stress increase prior to the 2022 Menyuan Ms 6.9 earthquake. The mechanical fracturing of surrounding limestone rocks during the slipping movement of LLLF could facilitate the water-rock interactions. Compared to three-month observations after the main shock, relatively higher concentrations of HCO3− and heavier δ18OH2O values of the LHG springs were also observed in the short-term period. The shallow stored formation water might be squeezed along the cracks and rose to the surface during earthquake tremors, causing a sandblasting water phenomenon.

What is the appropriate content of [formula omitted] irrigated into tomato cultivation soil for enhancing its carbon fixation?

To improve the carbon fixation capacity of crops, HCO3− is applied to the rhizosphere under a suitable pH value, which can enhance the utilization of CO2 by crops. This study aimed to clarify the maximum fixation capacity of HCO3− in tomato plants by exploring the optimal concentration of HCO3− in their cultivation environment. The results showed that the tomato could maintain both the net increase of HCO3− fixation and normal growth, when the maximum concentration of HCO3− in the cultivation surroundings was discovered during the growth period: 25 mmol/L NaHCO3-solution in seed germination, 14 g-NaHCO3/kg-soil in the cotyledon development, 8 to 10 g-NaHCO3/kg-soil during the seedling, 6 g-NaHCO3/kg-soil in the flowering, and 9 g-NaHCO3/kg-soil in the fruiting. However, excessive HCO3− could impair the development of tomato plants, especially the vegetative growth at seedling/flowering stages and the root growth at fruiting stage due to the increased soil pH and EC by HCO3−. On the other hand, H2O produced by the decomposition of HCO3− by tomato plants could alleviate physiological stress under severe conditions. Therefore, HCO3− became the main inorganic carbon source of tomato assimilation under extreme stress. This study provides a data basis for selecting and optimizing the appropriate HCO3− application amount when CO2 is used for agricultural eco-fixation in the form of HCO3− in the future.

Effect of chloride and bicarbonate ions on corrosion behavior of carbon steel in anaerobic environment

This investigation was initiated to study the influence of chloride ions and bicarbonate ions on the corrosion behavior of Q345 carbon steel in anaerobic condition by electrochemical tests and surface characterizations. It was found that low concentration of Cl- tends to cause general corrosion of sample while high concentration of Cl- induces localized corrosion because of its migration to the corrosion defects, leading to the accelerated dissolution of matrix. The existence of individual HCO3- results in the passivation of sample. When Cl- co-exists in the solution, the increase concentration of HCO3- results in an overall decrease of corrosion pit depth and the disappearance of localized corrosion, revealing the inhibitory effect of HCO3- on corrosion due to the formation of dense FeCO3 film. This corrosion suppression behavior of HCO3- is opposite to its synergistic effect on pitting with Cl- in aerobic environment.

Rationalizing mineral gypsum use through microbially enriched municipal solid waste compost for amelioration and regaining productivity potential of degraded alkali soils

Reclamation of alkali soils to harness their productivity potential is more complex due to the presence of excess sodium ions, poor hydraulic conductivity and infiltration rate, resulting in poor plant growth and crop productivity. Sodic soil reclamation using inorganic ameliorants like mineral gypsum or phosphogypsum is beyond the reach of small and marginal farmers having alkali soils because of their higher market prices and shortage of availability. Conjoint use of inorganic and organic amendments can be a pragmatic solution for improving soil physico-chemical and biological properties and sustaining crop productivity. Municipal solid waste compost (MSWC) available in abundant quantity if enriched with the efficient halophilic microbial consortium and used in conjunction with a reduced dose of gypsum can be a cost-effective approach for sustainable reclamation of alkali soils and harnessing their productivity potential. Hence, a field experiment was conducted on a high alkali soil (pH2 9.2 ± 0.10), electrical conductivity (EC) 1.14 ± 0.12 dS m−1, exchangeable sodium percentage 48 ± 2.50 and organic carbon (0.30%) was conducted during 2018–19 to 2020–21 to study the combined effect inorganic and organic (enriched municipal solid waste compost (EMSWC)) amendments on amelioration of alkali soils and sustaining productivity of rice–wheat cropping system. Application of gypsum @ 25% GR + enriched MSW compost @ 10 t ha−1 (T6) showed significant improvement in soil physico-chemical and biological properties over the sole application of organic (T3 and T4), inorganic (T2) and control (T1). A significant improvement in soil fertility status in terms of available nitrogen and micronutrients as well as CO3, HCO3, Cl, Ca and Mg content were recorded with the combined application of organic and inorganic soil amendments (T5 and T6) over the sole application of mineral gypsum. Soil microbial biomass carbon (MBC), nitrogen (MBN) and phosphorus (MBP) improved significantly due to the application of EMSWC with gypsum over the application of gypsum only. Grain yield of rice and wheat increased significantly (P < 0.05) owing to the application of a reduced dose of gypsum (25% GR) and EMSWC @ 10 t ha−1 (T6) with values of 5.55 and 3.83 t ha−1, respectively over rest of the treatments. Three years economic analysis of the study revealed that treatments T6 and T5 gave the highest positive net return whereas it was lowest in treatment T1 and negative in treatment T2. The highest benefit-to-cost ratio (B:C) was obtained in treatments T6 and T5 which were significantly higher compared to the rest of the treatments.

Geochemical Analysis of Hot Springs in Massepe, Tellu Limpoe Sidenreng Rappang Regency, South Sulawesi Province, Indonesia

Location of the study is administratively located in the District Tellu Limpoe, Sidenreng Rappang Regency in South Sulawesi Province. Geographically located at coordinate 119°47'00" – 119°49'00" east longitude and 04°00'00"– 04°02’00" latitude. This study aims to determine the geological conditions and geochemical, it is hot spring types, and subsurface temperature of the geothermal Massepe area Sidenreng Rappang district of South Sulawesi Province. Methods of research are conducted in the form of data collection methods and methods of geological and geochemical laboratory analysis. The geomorphology of the study area consists of one unit, the unit is flat. The type of developing river is the river periodically with stadia geomorphology including adults. The stratigraphy of the study area is divided into two units of rocks, it is rock units of ignimbrite from Pare – Pare Volcanics Formation of Pliocene age and rock units of basalt from Soppeng Volcanics Formation of Early Miocene – Middle Miocene. The structure that developed in the research area is a joint and strike–slip fault, it is a Massepestrike–slip fault. Geothermal manifestations in the study area consist of 3 stations hotspring. The percentage values of ion content of HCO3-, Cl-, and SO42- in hot water samples were analyzed, indicating that the hot springs area of research, including the chloride water type. Estimation of subsurface temperature by using the geothermometer Na - K in the research area at station 1 – 3 is 162°C - 168°C, using the geothermometer Na - K - Mg are known, that the hot springs in the area of research included in partially equilibrated.

Reaction of FeaqII with Peroxymonosulfate and Peroxydisulfate in the Presence of Bicarbonate: Formation of FeaqIV and Carbonate Radical Anions.

Many advanced oxidation processes (AOPs) use Fenton-like reactions to degrade organic pollutants by activating peroxymonosulfate (HSO5-, PMS) or peroxydisulfate (S2O82-, PDS) with Fe(H2O)62+ (FeaqII). This paper presents results on the kinetics and mechanisms of reactions between FeaqII and PMS or PDS in the absence and presence of bicarbonate (HCO3-) at different pH. In the absence of HCO3-, FeaqIV, rather than the commonly assumed SO4•-, is the dominant oxidizing species. Multianalytical methods verified the selective conversion of dimethyl sulfoxide (DMSO) and phenyl methyl sulfoxide (PMSO) to dimethyl sulfone (DMSO2) and phenyl methyl sulfone (PMSO2), respectively, confirming the generation of FeaqIV by the FeaqII-PMS/PDS systems without HCO3-. Significantly, in the presence of environmentally relevant concentrations of HCO3-, a carbonate radical anion (CO3•-) becomes the dominant reactive species as confirmed by the electron paramagnetic resonance (EPR) analysis. The new findings suggest that the mechanisms of the persulfate-based Fenton-like reactions in natural environments might differ remarkably from those obtained in ideal conditions. Using sulfonamide antibiotics (sulfamethoxazole (SMX) and sulfadimethoxine (SDM)) as model contaminants, our study further demonstrated the different reactivities of FeaqIV and CO3•- in the FeaqII-PMS/PDS systems. The results shed significant light on advancing the persulfate-based AOPs to oxidize pollutants in natural water.

Analysis of the Hydrochemical Characteristics and Genesis of Bosten Lake, China

The hydrogeochemical evolution of Bosten Lake has an important impact on the lake’s ecology and water environment. Kriging interpolation, principal component analysis and Piper and Gibbs charts were used to analyze the hydrochemical characteristics and genesis of Bosten Lake in summer and autumn. The following are the main conclusions: (1) In summer and autumn, the hydrochemistry of the lake follows the order of SO42− &gt; Cl− &gt; HCO3− &gt; Na+ &gt; Mg2+ &gt; Ca2+ &gt; K+. (2) The concentrations of TDS, Ca2+, Na+, Mg2+, Cl− and HCO3− in Bosten Lake increased significantly in autumn. Ion concentrations in most of the Little Lake District were higher than those in the Great Lake District. (3) In summer, ion correlation was strong, the evaporation effect was strong and the TDS contribution rate was high. Evaporation was weak in autumn, and Mg2+ and Ca2+ contributed more. (4) The hydrochemical type (SO4·Cl-Na·Mg) was the same in both seasons; in summer, the Great and Little lakes were mainly characterized by evaporation and crystallization; in autumn, evaporation crystallization was dominant in the Great lake. (5) The ions mainly came from the dissolution of gypsum, salt rock, calcite, etc. Cationic alternating adsorption occurred in summer.

Numerical simulation of the effects of the EGR ratio and ignition timing on a supercharged and high compression ratio hybrid gasoline engine

This paper explores the potential effects of the exhaust gas recirculation (EGR) ratio and ignition timing on knock suppression in a supercharged and high compression ratio (CR) hybrid gasoline engine, whereas previous knock studies have focused on conventional CRs and equivalence ratios. According to the simulation results, EGR can significantly reduce the knock intensity (KI). The high CR and EGR enable the realization of an indicated thermal efficiency of 47.46 %. Chemical modeling and solvers make free radical detection convenient. Therefore, this paper investigates the relationships between chemical kinetics and low-temperature reactions, preignition (PI) and spontaneous combustion of end mixtures (SCEM). The numerical results demonstrate that IC4H7 is an important indicator of low-temperature reactions. In the cases where SCEM and PI occur, H2O2 and CH2O substantially decompose and the masses of CH3, HCO, and CO start to decrease before the peak heat release rate (HRR) is attained. High CH2O concentration is an important indicator for high-temperature reactions, while high concentrations of CH3 and HCO can characterize the onset of SCEM or PI. The peak masses of IC4H7, HCO, and CH3 positively correlate with the KI value.

An evaluation of waste and well water quality for agriculture production around Erbil city, Iraq

Erbil city is located in the northern Iraq with a population of over one million people. Due to water crises farmers usually use wastewater and well water for the agricultural production. In this study six stations were designed to sample waste water and three from well water to define waste water and ground water characteristics. In this study, Residual Na+ Carbonate, Mg++ hazard, salinity hazard, Kelley index, %sodium, total hardness, permeability index, potential salinity, sodium adsorption ratio, and Irrigation Water Quality Index (IWQI) were determined. The order of average cation concentrations in water was Mg2+&gt; Ca2+ &gt; Na+ &gt; K+. While the proportion of main anions in water were HCO3 &gt;SO4 &gt; Cl. The highest concentrations of Ca2+, Mg2+ and Na+ were found in well water, while the highest concentration of K+ was found in wastewater. The maximum concentration of HCO3 and Cl recorded in well water, while the highest concentration SO4 recorded in wastewater. Moreover, the order of trace elements was Pb &gt; Al &gt; Fe &gt; Cd &gt; As &gt; Mn &gt;Cr &gt; Ag &gt; Ni. Keeping in mind metal concentration set by US EPA and FAO (1999) and (1994) guidelines the levels of Pb, Al, Fe, Mn, Cr, Ag and Ni in the waste and well water were within the admissible limitations for irrigation schemes. Moreover, limitations of As and Cd were beyond permissible limitation need to be reduced. The IWQI ranged from 88.92 to 95.09 in the waste water samples. Overall assessment reveals that cultivated agriculture plants were secured from toxic compounds.

Strategies for the Remediation of Cadmium and Chromium From Industrial Effluents in Response to Amaranthus Cruentus, Spinacia Oleracea And Amaranthus Viridis of Bangladesh

Discharge of industrial effluents and their remediation in relation to crop production are the major concerns. Accordingly, the color, pH, EC, total dissolved solids (TDS), dissolved oxygen (DO), chemical oxygen demand (COD), total hardness, chloride, CO3, HCO3, alkalinity, Cu, Cd, Pb, Mn, Zn, and Cr contents in the effluents discharged from Hazaribagh tannery and Tejgaon textile industries in Dhaka were determined. These effluents had no significant (p≤0.05) effects on soil pH but exerted significant positive effects on the CEC of the soil. The TDS of the effluents were also high but it decreased by alum [K2SO4 Al2 (SO4)3 24 H2O] treatment (0.1%). The DO of the effluents was low and the COD was high leading to a serious threat for aquatic lives. The concentrations of Cd, Pb, Zn, Mn and Cr were high. Filtration through natural sand-gravity-filter acts like Effluent Treatment Plant-ETP and coagulation of effluents by alum decreased the concentrations of Cd and Cr below the permissible limits. The treated effluents were used for the production of vegetables of red amaranth (Amarunthus cruentus), green spinach (Spinacia oleracea) and green amaranth (Amarunthus viridis) grown in a non-polluted soil under pot experiments. Application of treated effluents was found to have significant (p≤0.05) positive effects on the biomass production of the vegetables. The highest amounts of assimilation of Cd in plants were recorded for the Green spinach followed by Green amaranth and for Cr, the order was green spinach followed by red amaranth and green amaranth vegetables grown under the treated effluents of tannery and textile industries. The present study revealed that the natural sand-gravity-filter (i.e., Economic ETP) and alum treatments were found to be effective not only for the remediation of polluted effluents but also improved the growth of vegetables. The use of natural filter and/or alum treatment can be practiced for the remediation of pollution of industrial effluents before discharging from industries. J. Biodivers. Conserv. Bioresour. Manag. 2022, 8(2): 109-118

Impact of Construction and Functioning of a Newly Built Ski Slope on the Quality of Nearby Stream Water

The construction of new, artificially snowed, ski slopes and the accompanying infrastructure changes the natural environment and exerts pressure on the ecosystems. This study examined the impact of the construction and operation of a new ski slope, with its infrastructure and artificial snow production, on the quality of nearby stream waters. The research period covered the time before, during and after the slope construction. Electrolytic conductivity (EC) and pH were measured on-site, chemical analyses included the determination of Ca2+, Mg2+, Na+, K+, HCO3−, SO42−, Cl−, NO3−, and microbiological analysis comprised mesophilic and psychrophilic bacteria, total and fecal coliforms, and E. coli. As a result of intensive environmental transformations, the examined parameters varied significantly over the study period, as shown by the coefficient of variation. Due to land cover changes, concentrations of all the examined parameters increased during the ski slope construction due to ions and bacteria leaching from the soil. However, when construction works were finished, all bacterial and some chemical indicators returned to the state observed before the construction, most probably due to the recovery of vegetation and self-purification of water. Supply of melt water from artificial snow, produced from water containing higher concentrations of ions, increased pH, EC, Ca2+, Mg2+ and HCO3− in the stream. Providing that the development of ski stations is unavoidable in the considered region, conducting studies assessing the impact of new ski slope construction is an important step that should be conducted prior to undertaking such investments.

Effect of Water Treatment on the Chemical Composition of Drinking Water: A Case of Lovozero, Murmansk Region, Russia

The surface waters in Russia’s Murmansk Region used for public water supply are exposed to the negative impact of dust particles carried from the storage facilities for mining waste. For example, lanthanides and other rare metals enter the surface waters in Lovozero District from the tailings storage facilities (TSFs) of the Lovozero Concentrator, which requires thorough water treatment of drinking water. Using the monitoring data of the natural water of the Virma River and of the tap water in the residential community of Lovozero, Murmansk Region, and with the help of physical and chemical modeling (in the software suite Selector), we examined the effect of reagents used in water treatment on water chemistry. It was shown that the use of aluminum polyoxydichloride coagulant can lead to an increase in the concentration of aluminum and chlorine in water, a change in pH and Eh values. The use of liquid chlorine leads to a decrease in pH values and a change in the concentration of HCO3−, which entails a change in the forms of migration of calcium and lanthanides in solution. The composition of the precipitated phases changed, which indicates a change in the water chemistry, demonstrating that the applied water treatment technology adopted in Lovozero fails to improve water quality. It was shown that replacing liquid chlorine (a hazardous reagent) with NaOCl optimized the water treatment process, eliminating the need to stabilize the pH by adding sodium. Physical and chemical modeling was found to be useful for studying and optimizing water treatment processes.

Production, physiological response, and calcium and magnesium balance of lactating Holstein cows fed different sources of supplemental magnesium with or without ruminal buffer

The objective of this study was to evaluate the effects of dietary replacement of magnesium oxide (MgO) with calcium-magnesium hydroxide [CaMg(OH)2] and its interaction with ruminal buffer (sodium sesquicarbonate) supplementation on production, Ca and Mg balance, and overall physiological response of mid-lactation Holstein dairy cows. Sixty cows averaging 40.5 ± 7.0 kg of milk/d were used. Treatments were assigned following a 2 × 2 factorial arrangement: (1) MgO, (2) MgO + buffer, (3) CaMg(OH)2, or (4) CaMg(OH)2 + buffer. Diets were formulated to have 16.5% of crude protein, 1.82 Mcal/kg of net energy for lactation, 0.67% Ca, 0.39% P, and 0.25% Mg, all on a dry matter (DM) basis. Treatments were individually top dressed. Milk production, composition, and DM intake were evaluated. A subsample of 20 cows were randomly selected for the evaluation of Ca and Mg balance, blood gases, and electrolytes. Ruminal fluid was also collected for evaluation of pH and Ca and Mg solubility. Effects of Mg source, buffer, and the interaction Mg source × buffer were analyzed through orthogonal contrasts. An interaction of Mg source × buffer was found for DM intake and feed efficiency, in which cows fed CaMg(OH)2 had a similar feed efficiency regardless of ruminal buffer inclusion; however, when cows were fed MgO, the inclusion of buffer reduced feed efficiency. No effects on body weight and milk yield were observed. Buffer addition tended to increase the concentrations of fat, protein, and solids-not-fat, without affecting the yields of these milk components. Magnesium source and buffer did not affect ruminal fluid, blood, urine, or fecal pH; however, buffer supplementation increased urinary pH. Treatment with CaMg(OH)2 increased blood concentration of HCO3-, total CO2, and base excess compared with cows fed MgO. No differences were observed in the ruminal solubility of Ca and Mg or on milk or urinary Ca and Mg excretion. Greater plasma Mg concentration was observed for animals fed MgO compared with cows fed CaMg(OH)2; however, both sources were above the threshold recommended in the literature for dairy cows. Also, a reduction in fecal Mg excretion was observed in animals fed CaMg(OH)2. In summary, we provide evidence that CaMg(OH)2 could replace MgO without affecting performance, overall physiological response, or Ca and Mg balance of mid-lactating dairy Holstein cows.

Arterial blood gases' analysis in elite breath-hold divers at extreme depths.

To showcase results of arterial blood gases' analysis in elite breath-hold divers sampled at depths where their total lung capacities are below their residual lung volume on surface. Three male elite breath-hold divers performed body plethysmographies to determine their lung volumes. Two dives were performed, one on normal inhalation to 60m of depth and the second on complete exhalation to 10m of depth. Blood samples were taken on five occasions; before the first dive, at 60 and 10m of depth and immediately after resurfacing after both dives. Arterial blood gases' analysis at 60m of depth showed an increase in partial pressures of oxygen and carbon dioxide, a consequent decrease in pH and an increase in concentration of HCO3-. After resurfacing, in two divers, values mostly returned to normal; hypoxemia was observed in one diver. At 10m of depth, all values showed similar variation, and hypoxemia was observed in the same diver but at depth. Upon resurfacing, all values returned to normal. This is the first study performed at depths where the total lung capacities of participants are below their residual lung volumes at the surface. Partial pressure of carbon dioxide increases at depth to higher than normal values causing pH to decrease thus exceeding the buffering potential of the blood. In addition, previous assumptions that maximum depth in breath-hold divers is where total lung capacity is reduced to their residual volume proved wrong as our group of divers had no symptoms after resurfacing.

An optimal dietary sodium chloride supplemental level of broiler chicks fed a corn-soybean meal diet from 1 to 21 days of age.

Sodium chloride (NaCl) is usually added to diets to meet the Na and Cl requirements of broilers in the Chinese poultry industry, but the optimal dietary NaCl supplemental level was not well-established. The present study was conducted to estimate the optimal dietary NaCl supplemental level of broilers fed a corn-soybean meal diet from 1 to 21 days of age. A total of 490, 1-day-old Arbor Acres male broilers were fed a NaCl-unsupplemented corn-soybean meal basal diet (control) and the basal diet supplemented with 0.10, 0.20, 0.30, 0.40, 0.50 or 0.60% NaCl for 21 days. Regression analysis was conducted to evaluate the optimal dietary NaCl level using the best fitted broken-line or asymptotic models. As dietary supplemental NaCl levels increased, average daily gain (ADG), average daily feed intake (ADFI), blood partial pressure of CO2, total CO2, base excess and anion gap, blood concentrations of HCO3, Na and Cl, serum Na concentration, jejunal villus height (VH) and tibia ash content increased linearly and quadratically (P < 0.05), while feed/gain ratio, relative weights of heart, liver and kidney, blood K concentration, serum concentrations of K, uric acid and glucose, and osmotic pressure decreased linearly and quadratically (P < 0.05). The estimates of optimal dietary NaCl levels were 0.20-0.22% based on the best fitted broken-line or asymptotic models (P < 0.0001) of ADG, ADFI and feed/gain ratio, and 0.08-0.24% based on the best fitted broken-line or asymptotic models (P < 0.0001) of blood gas indices, serum parameters, jejunal VH, tibia ash content and organ indices. These results suggested that the optimal dietary NaCl supplemental level would be 0.24% for broilers fed the corn-soybean meal diet from 1 to 21 days of age, which is lower than the current dietary NaCl supplemental level (0.30%) in the Chinese broiler production.

Evaluation of water quality and its non-cancer risk in the rural environment of Bundelkhand region: geochemical and statistical approaches

ABSTRACT The Bundelkhand region of Central India has been facing increasing severity of droughts, water-level depletion and deterioration in water quality. In this perspective, an attempt has been made for a qualitative evaluation of surface and groundwater resources belonging to the rural environment of this region to understand the contaminant’s source and probable human health risk due to the intake of the available water. The water samples collected from this region were analysed for pH, electrical conductivity (EC), total dissolved solids (TDS), turbidity, total hardness (TH), major anions (F−, Cl−, HCO3 −, SO4 2−, NO3 −) and major cations (Ca2+, Mg2+, Na+, K+). The observations revealed a near-neutral to slightly alkaline nature of the studied water samples. The computed water quality index implies that around 82% water samples are of good to excellent category for drinking uses. Turbidity, TDS, TH and NO3 − were identified as the major parameters which violate the limits of drinking water. Geochemical investigations in association with multivariate statistical analysis identify carbonate weathering in coordination with the ion-exchange process as the major hydrogeochemical mechanism controlling the solute chemistry and concentrations of TH, TDS, HCO3 −, F−, Ca2+, Mg2+ and Na+. On the contrary NO3 −, Cl−, SO4 2− and K+ were strongly associated with anthropogenic activities. Water at most of the locations expresses positive saturation indices with respect to calcite and dolomite minerals, inferring the precipitation of these mineral phases. Sodium adsorption ratio (SAR) and percent sodium (%Na) values show a low alkali hazard and water can be used safely for irrigation purposes. However, high salinity in 39% of the water samples makes it unfit for application in agricultural fields. The non-carcinogenic hazard indices (HI) calculated by adding hazard quotient values of NO3 − and F− for child, adult male and female population show that more than 64% of the water samples are deemed to be unfit for human consumption.

Effect of boiler feed water composition on inorganic scaling in once-through steam generators estimated using a Monte Carlo modelling approach

Once-through steam generators (OTSGs) produce steam required to recover hydrocarbons from oil sand deposits. OTSGs generate steam at high pressure and temperature, using boiler feed water (BFW) derived from produced water, recycled condensate boiler blowdown (BBD), and small amounts of make-up water sourced from local groundwater. During the OTSG operation cycle, BFW undergoes significant physical and chemical changes, which can cause varying degrees of mineral (scale) precipitation, depending on the BFW quality. Scaling has negative impacts on OTSG performance and has in the past resulted in OTSG tube leaks.In this study, we performed thermodynamic simulations using a Monte Carlo approach with the objective of determining how the composition of the BFW and the steam quality affect scaling. We used 3 different scenarios, characterized by low, intermediate, and high iron-to-BFW ratios to represent various situations of BFW interaction with OTSG pipes. Within each scenario, BFW compositions were randomly assigned within industry-relevant variations of variables including steam quality, pH, and concentrations of SiO2(aq), Mg2+, Ca2+, Fe2+, Cl−, HCO3−, K+, Na+, SO42− and O2 and were allowed to precipitate scales according to thermodynamically controlled solubilities of minerals as they were heated and boiled. Our results show that inorganic scale in OTSGs is composed mostly of aegirine and various Mg and Mg/Ca silicates. We show that the concentrations of dissolved Si, Mg, and Fe available for interaction with BFW are the main factors controlling the mass and mineralogy of scale, whereas the total dissolved solids (TDS) and Ca concentrations within typical chosen operating limits have negligible impact on the scale mass in OTSGs. The modelling results further indicate that efforts to minimize the concentration of Mg in BFW to very low levels (<0.01 mg/kgBFW) show great promise for minimizing inorganic scale formation in OTSGs. Our equilibrium modelling revealed that steam quality has little impact on the total mass of inorganic scale formed in OTSGs because most of the mineral precipitation occurs at temperatures below 250 °C, before boiling starts. However, this finding may not be fully valid if strong kinetic barriers prevent process waters from achieving equilibrium via scale precipitation, especially at lower temperatures. Moreover, because nucleated minerals may be transported through the OTSG without precipitating on the piping walls, increasing steam quality reduces the capacity of BBD to carry over crystallized mineral phases in suspension.