Minerals Ca Research Articles

Chemical models for martian weathering profiles: Insights into formation of layered phyllosilicate and sulfate deposits

Numerical chemical models for water–basalt interaction have been used to constrain the formation of stratified mineralogical sequences of Noachian clay-bearing rocks exposed in the Mawrth Vallis region and in other places on cratered martian highlands. The numerical approaches are based on calculations of water-rock type chemical equilibria and models which include rates of mineral dissolution. Results show that the observed clay-bearing sequences could have formed through downward percolation and neutralization of acidic H2SO4–HCl solutions. A formation of weathering profiles by slightly acidic fluids equilibrated with current atmospheric CO2 requires large volumes of water and is inconsistent with observations. Weathering by solutions equilibrated with putative dense CO2 atmospheres leads to consumption of CO2 to abundant carbonates which are not observed in clay stratigraphies. Weathering by H2SO4–HCl solutions leads to formation of amorphous silica, Al-rich clays, ferric oxides/oxyhydroxides, and minor titanium oxide and alunite at the top of weathering profiles. Mg-Fe phyllosilicates, Ca sulfates, zeolites, and minor carbonates precipitate from neutral and alkaline solutions at depth. Acidic weathering causes leaching of Na, Mg, and Ca from upper layers and accumulation of Mg-Na-Ca sulfate-chloride solutions at depth. Neutral MgSO4 type solutions dominate in middle parts of weathering profiles and could occur in deeper layers owing to incomplete alteration of Ca minerals and a limited trapping of Ca to sulfates. Although salts are not abundant in the Noachian geological formations, the results suggest the formation of Noachian salty solutions and their accumulation at depth. A partial freezing and migration of alteration solutions could have separated sulfate-rich compositions from low-temperature chloride brines and contributed to the observed diversity of salt deposits. A Hesperian remobilization and release of subsurface MgSO4 type solutions into newly-formed depressions could account for formation of some massive layered sulfate deposits through freezing or evaporation. This scenario explains the observed deficiency of salts in Noachian formations, a paucity of Hesperian phyllosilicates, and the occurrence of sulfate deposits in Valles Marineris troughs, chaotic terrains, and some craters of the Hesperian age.

Role of some Herbs in Improvement of Mineral Absorption, Control of Anemia and Osteopenia in Rats دور بعض الأعشاب فى تحسين امتصاص الأملاح المعدنية والتحکم فى أنيميا نقص الحديد فى الفئران

asfunctional food supplement to improve Ca, P, Mg and Fe absorption aswell as to prevent and treat both anemia and osteoporosis associatedwith deficiency in calcium and iron intake were evaluated in rats. Threeexperimental groups were fed diet supplemented with 10% tested herbsfor 4 wk versus the control rat group fed basal diet free in iron andcalcium. At the end of the experiment, rat groups fed herbssupplemented diets were characterized by significant dose-relatedincreases in the level of serum minerals Ca (2.1 ± 0.03 to 2.58 ± 0.01mmol/L), P (0.72 ± 0.3 to 0.93 ± 0.02 mmol/L), Mg (0.71 ± 0.01 to0.91 ± 0.01 mmol/L) and Fe (69.11 ± 4.55 to 84.3 ± 2.12 μg/dl). Inaddition, there were variable increases in the measured levels ofhemoglobin (11.11 ± 1.1 to 14.25 ± 1.1 g/L), hematocrit (39.15 ± 0.15to 42.15 ± 1.27 %) and ferritin (49.55 ± 2.25 to 65.12 ± 0.15 μg/dl) inherbs fed groups in a dose-dependent fashion compared with thecontrol group. These data suggested that Safforn

Inhibition of Cr(III) oxidation during thermal treatment of simulated tannery sludge: The role of phosphate

The presence of Ca compounds may be an important factor contributing to oxidation of Cr(III) to Cr(VI) during the incineration of tannery sludge. In this study, Cr(III) oxidation was inhibited by preventing Ca participating in Cr(III) oxidation reactions via incorporating it in phosphate minerals. Cr(III) oxidation was remarkably suppressed through immobilizing Ca in phosphate minerals. Around 16% of Cr(III) would be oxidized in samples without phosphate heated at 900°C for 1h, which could be reduced substantially to 0.25% with the addition of phosphate at n(P)/n(Ca)=2. Moreover, phosphate not only captured free CaO, inhibiting Cr(III) oxidation, but seized Ca from CaCrO4, resulting in formed Cr(VI) being reduced. Inhibition of Cr(III) oxidation performed resistant to elevating temperature over 1000°C and prolonged retention time, due to the irreversible incorporation of Ca into phosphate mineral species. Moreover, incorporating Ca into phosphate minerals thoroughly eliminated the potential of Ca to trigger Cr(III) oxidation. Additionally, the P-hosting phases produced (e.g., Ca(PO3)3 and Cr(PO3)3) were also able to capture free CaO and inhibit Cr(III) oxidation, so Cr(III) oxidation continued to be inhibited during flue gas cooling and fly ash reheated process. A case study, in which tannery sludge was heated, confirmed that adding phosphate effectively inhibited Cr(III) oxidation. Adding phosphate could therefore be an effective way of inhibiting Cr(III) oxidation when solid waste containing Cr(III) is heated.

Effect of Treatments (Lemon, Mustard and Garlic) on the Minerals Value of Smoked Hilsa (<i>Tenualosa ilisha</i>) During Storage Period

The study was designed to investigate the effect of both the duration of storage and treatments (lemon, mustrard and garlic) methods on minerals (Ca, P, Fe, Mn, Cu, Mg and Zn) value of smoked hilsa in six selected regions (Chandpur, Barisal, Patuakhali, Bhola, Shariatpur and Cox’s Bazar). Minerals (Ca, P, Fe, Mn, Cu, Mg and Zn) composition was increased by treatments but gradually decreased variedly with duration of storage smoked hilsa. The calcium (Ca), phosphorus (P), iron (Fe), manganese (Mn), copper (Cu) magnesium (Mg) and zinc (Zn) were found 910.55±11.79 to 853.57±11.09 mg/100g, 228.53±4.37 to 83.60±8.75 mg/100g, 12.45±0.97 to 7.07±1.85 mg/100g, 21.58±0.48 to 7.89±0.75 mg/100g, 3.15±0.16 to 0.90±0.05 mg/100g, 60.54±10.66 to 36.31±1.85 mg/100g and 2.97±0.10 to 0.92±0.02 mg/100g respectively. Generally, the minerals reduced more in the first month of storage. The results suggest that storage period to be a negative effect on the minearls values of smoked hilsa. Hence, smoked hilsa should be consumed while fresh and if it is to be stored, the period must be as short as possible to provide optimal levels of minerals.

Effect of Different Environmental Factors on Some Haematological and Biochemical Parameters and Selected Blood Minerals in Ouled Djellal Ewes

The aim of this study was to investigate the impact of the altitude on the concentrations of the various blood parameters considered as good biological markers of ewes. A total of 160 ewes having 3-5 years of age, multiparous, non-pregnant, non-lactating and reared in arid areas of South East Algeria were included. The plasma concentrations of glucose, cholesterol, triglycerides, total proteins, urea and creatinin were determined as well as minerals (Ca, P) and hematological parameters (haemoglobin, haematocrit). No significant variation (P>0.05) of hematological parameters and mineral levels was detected between the plain and tableland ewes. Same observation was found for biochemical parameters but between mountain and tableland ewes. While cholesterol, triglyceride, total proteins and urea levels were higher (P<0.01) at the altitude of 150m, hemoglobin, haematocrit and creatinin, were significantly lower (P<0.05) at the same altitude. The study found lowest glucose concentrations were detected at 600m. Moreover, the results of the study showed the highest calcium concentration was found at the altitude of 150 m and the lowest at the altitude of 1000 m (1.12±0.35 mmol/L vs. 0.52±0.03 mmol/ L). Phosphorus levels were higher at altitudes of 150 m than at the altitude of 600 m and 1000 m (0.93±0.42 mmol/ L vs. 0.68±0.54 mmol /L, 0.23±0.01mmol/ L). The highest haemoglobin concentration and value of haematocrit were detected in mountain ewes at the altitude of 1000 m (120.61 g/ L, 40%) and the lowest at the altitude of 150 m (73.2 g/ L, 31%) (P<0.001). We concluded that haematological and biochemical parameters in Ouled Djellel ewes reared in arid area may be impacted by altitude.

Statistical aspects of variations in hair mineral measurements

The objective of this study is to examine the variations in hair mineral concentrations measured by particle induced X-ray emission (PIXE). As the concentrations reflect the historical profile of minerals in blood for a few days to several years, hair mineral measurements vary among the hair strands of a sample as well as the locations on hair strands where PIXE beams are irradiated. PIXE analysis presents not only mineral measurements but also standard errors associated with them due to uncertainty in fitting analysis of X-ray spectrum. We developed statistical methods to decompose the intra-individual variance into the variances due to locations and that due to the fitting analysis. This study describes the results of statistical analysis on the variations in six minerals (Cu, Fe, Sr, Ca, Cl and Pb) and compares the results for better understanding of variations in hair mineral measurements obtained from hair analysis using PIXE.

Functional Oligosaccharide DFA III Forming Enzyme Produced by Microorganisms

Inulin is a polysaccharide found in various plants (chicory, dahlia, and so on). A unique oligosaccharide DFA III (di-fructose di-anhydride III) is formed from inulin with a special microbial enzyme. This enzyme was named as inulin fructotransferase (DFA III-producing) [EC 4.2.2.18]. The oligosaccharide DFA III has sweetness half as sucrose. The DFA III also has a special quality that promotes the assimilation of minerals (Ca, Fe, and so on) from intestines. Therefore, the oligosaccharide DFA III has a unique potential for the prevention of osteoporosis and iron deficiency anaemia. The sales in the market of DFA III were started in 2004 in Japan. Now, we can purchase a product of supplement containing the DFA III and a mineral in a pharmacy and a convenience store in Japan. In this article, we summarize the research on the oligosaccharide DFA III forming enzyme produced by the microorganisms.

Identification of Novel Metabolites along with the Assessment of Metal Toxicity and its Implication in Marine Red Alga &lt;i&gt;Hypnea musciformis&lt;/i&gt;

Marine algae are known to contain a wide variety of bioactive compounds, biomaterials derived from marine algae have commercial applications in pharmaceutical, medical, cosmetic, nutraceutical, food and agricultural industries. Marine algae are found to contain high amount of nutrients, vitamins (A, B, C, D & E), minerals (Ca, P, Na & K), antioxidants and dietary fibers, that’s why they are used as food, fodder and other commercial purposes throughout the world. Seaweeds have been used as an important source of food because of their biochemical composition. They are also very rich in novel compounds and can be explored for the development of drugs to combat deadly diseases like cancer, diabetes etc. The present study indicates the presence of bioactive compounds by using HPLC and FTIR in marine algae Hypnea musciformis . It includes polysaccharides, terpenes, alkenes, sterols etc. These results indicated that seaweeds H. musciformis could be potential sources of development novel bioactive compounds. Similarly the heavy metals analyzed were found in less concentration and does not have any effects. It was (Cd, Fe, Cu, Ca, Cr, Pb, Ni, Co, Mn, Zn) metals were estimated using atomic absorption spectroscopy. Seaweeds can provide a dietary alternative due to its nutritional value and its commercial value can be enhanced by improving the quality and expanding the range of seaweed-based products. In the future, these marine algae-derived materials/compounds will be used more often in pre-clinical studies for drug discovery.

Improvement of a sustainable hybrid technology for caseins isoelectric precipitation (electrodialysis with bipolar membrane/ultrafiltration) by mitigation of scaling on cation-exchange membrane

Abstract Electroacidification of milk by electrodialysis with bipolar membranes (EDBM) can be performed to produce isoelectric precipitated casein. In spite of advantages of EDBM, a problem of fouling hampers the industrial application of this technology. There are two types of fouling occurring during milk electroacidification such as protein fouling inside the EDBM stack and scaling on cation-exchange membrane (CEM). Recent studies demonstrated that protein fouling can be avoided by coupling an EDBM module with an ultrafiltration (UF) module. The present study aims the mitigation of scaling on the CEM. In order to attain this goal, two approaches were tested: 1) addition of KCl in the milk reservoir and 2) use of a UF membrane allowing higher permeate flux and consequently higher flow rates of solutions in the EDBM stack. Results of this study demonstrate the reasonableness of both approaches resulting in the significant decrease of CEM scaling (more than 30%). Industrial Relevance Caseins are the major milk proteins largely produced in the world (around 330 000 t per year) and widely applied in the food and pharmaceuticals industries. There are several relevant features of proposed method (electrodialysis with bipolar membranes coupled with ultrafiltration (EDBM-UF)) for the casein production such as 1) absence of the hazardous reagents; 2) high purity of caseins due to the demineralization during EDBM; 3) no waste generation; 4) the base stream from EDBM module (co-product) can be used for the formation of caseinates. The present work demonstrates the significant decrease of scaling on the cation-exchange membrane (more than 30%), which is the major problem of the EDBM-UF process. Indeed, during milk acidification, there is a liberation of minerals (Ca 2 + and Mg 2 + ), which form the membrane deposit. This deposit negatively affects the process performance and leads to the membrane replacement. The cost of ion-exchange membranes in ED module comprises a major part of the total cost of EDBM-UF process. Thus, control and prevention of the membrane deposit will allow to increase a lifetime of ion-exchange membranes and to decrease a price of EDBM-UF treatment.

COMPARISON OF THE ABILITY OF LIMESTONE AND CONCRETE TO REMOVE HEAVY METAL IONS FROM CONTAMINATED WATER

The dissolving potential of the Ca–minerals in concrete and limestone; and precipitation potential of metal ions from model acid water has been examined with attention to change of pH during the batch tests (L/S ratio = 300 ml /0.5 g, L = model solution with Mx+ (Ni; As; Zn; Cu; Fe) cations and (SO4)2- anion). Both of materials are the source of alkalinity-generating and move pH of acid solution to alkali region. The neutralization initiates the precipitation of metal contaminants in form of insoluble compounds. It was confirmed, that concrete is able to edit pH value more significantly at test conditions than limestone (calcite) if the initial pH of water is  1.5. Main effective compound of concrete is the portlandite – Ca(OH)2. The fact that concrete generated more alkaline environment during two hours tests the metal ions have been removed from water by concrete more effectively (100 %).

Phosphorus removal performance and speciation in virgin and modified argon oxygen decarburisation slag designed for wastewater treatment

Argon oxygen decarburisation (AOD) slag may be used for phosphorus (P) removal, as its high pH and weatherable calcium (Ca) minerals provide sufficient Ca2+ and OH− for calcium phosphate (Ca–PO4) precipitation. This study examined the P removal performance of AOD slag for use as wastewater treatment material. Batch experiments were carried out using both synthetic P solution and real wastewater, followed by chemical modelling and X-ray absorption near edge structure (XANES) spectroscopy. The influences of initial P concentration, slag dose and modification by polyethylene glycol (PEG), an effective agent for generation of porous materials, were investigated to determine the optimal conditions for P removal by AOD slag. It was found that virgin AOD slag removed 94.8% of P from a synthetic P solution in 4 h and 97.8% in 10 h. This high P removal was accompanied by a rapid increase in pH from 7.0 to 10.74. The maximum P removal capacity (PRC) from synthetic P solution ranged from 1.3 to 27.5 mg P g−1. The optimal AOD dose for P removal from wastewater, determined in 8-h batch experiments, was 25 g L−1. PEG modification increased the reaction rate and resulted in higher final pH, increasing PRC by 47.9%. Combined Visual MINTEQ and XANES analysis for detailed examination of P removal mechanisms revealed that the main P removal mechanism was precipitation of calcium phosphate. According to the XANES analysis, the main Ca–PO4 precipitate formed on virgin AOD slag under low initial P concentration and high pH was apatite, while brushite was the dominant product at high initial P concentration and low pH.

Synthesis, characterization, and thermodynamics of arsenates forming in the Ca-Fe(III)-As(V)-NO3system: Implications for the stability of Ca-Fe arsenates

Arseniosiderite and yukonite are among the important arsenate minerals occurring as secondary alteration products in relation to the oxidation of arsenopyrite and arsenian pyrite and as discrete grains in some gold ores, mine tailings, and contaminated soils. Characteristics of these Ca-Fe arsenate species are not well known and our understanding of the conditions promoting their formation and dissolution is limited. Long- and short-range structural characteristics and thermodynamic properties of the Ca-Fe arsenates forming in the Ca-Fe(III)-As(V)-NO3 system were determined to better predict the mineralogical transformations taking place in neutralized sludge and tailings environments, and their influence on arsenic mobilization. Yukonite and arseniosiderite readily form from solutions with highly variable compositions at a wide pH range from slightly acidic to alkaline conditions. Calcium concentrations corresponding to molar Ca/(Ca+Fe+As) ratios as low as 0.1 appear to be adequate for their formation. Our experimental results confirm observations in natural settings and mine tailings where scorodite is progressively replaced by yukonite and arseniosiderite. The initial amorphous precipitates made of small oligomeric units of edge-sharing FeO6 octahedra with bridging arsenate evolve to yukonite through the establishment of corner linkages between the FeO6 chains. Yukonite represents a nanocrystalline precursor and Ca-deficient variety of arseniosiderite. Formation of arseniosiderite is kinetically controlled with faster development of crystallinity at neutral to slightly acidic pH and slower kinetics under alkaline conditions. Calorimetric measurements provided an enthalpy of formation value of −1950.3 ± 3.1 kJ/mol and standard entropy of 237.4 ± 4.4 J/(mol·K) for arseniosiderite [with composition Ca0.663Fe1.093(AsO4)(OH)1.605·0.827H2O], the corresponding Gibbs free energy of formation is −1733 ± 3.4 kJ/mol. A rough estimate of the thermodynamic properties of yukonite is also provided. Arseniosiderite is a stable arsenate between pH 3.5 and 7.5 in solutions saturated with respect to soluble Ca minerals such as calcite, gypsum, anorthite, or Ca-montmorillonite. Arsenic release from mine wastes and contaminated soils can be effectively controlled by arseniosiderite and the conditions promoting its formation such as lime-treatment leading to gypsum saturation in ferric arsenate solutions would prove to be desirable for stabilizing arsenic in the form of arseniosiderite in mine wastes.

Dietary phytase supplementation in rapeseed protein based diets influences growth performance, digestibility and nutrient utilisation in turbot (Psetta maxima L.)

In this study the performance of juvenile turbot (Psetta maxima L.) fed varying dietary phytase (Natuphos® 5000 G, BASF SE) supplementation levels was determined in a 56day lasting growth trial, followed by a digestibility trial. One control diet (C) based on fish meal and three test diets based on rapeseed protein concentrate (RPC) were produced. RPC based diets contained phytase levels of 0 (P0), 1000 (P1000) and 2000 (P2000) FTUkg−1. Feed intake and growth performance were significantly (p<0.05) improved in fish fed P1000 and P2000 compared to fish fed unsupplemented P0. Furthermore fish fed P2000 showed a significantly improved performance level, comparable to the control group, with regard to FCR, PER and ADC of protein. Also the ADC of ash and phosphorus increased significantly due to phytase supplementation. In contrast, the ADC of other investigated minerals Ca, Mn, Fe, Co, Cu, Zn and Mg were not significantly affected. Moreover, slightly increased retention of nitrogen and significantly increased retention of phosphorus were observed in fish fed P2000 compared to fish fed P0. In conclusion, the supplementation of phytase to plant protein based diets rich in phytic acid increases nutrient digestibility and utilisation, which can positively influence growth performance and nutrient emissions in turbot production. Statement of relevanceTo the best of our knowledge this is the first time that effects of dietary phytase incorporation were studied in turbot nutrition and the results consequently lead to a deeper insight and better understanding of this enzyme.The apparent digestibility coefficient (ADC) of protein and phosphorous increased significantly, which led to an improved growth and may lead to a more efficient utilisation of plant protein sources in turbot nutrition.Retention of nutrients (N & P) was also improved and gives the ability to a more sustainable turbot production via reduced phosphorus supplements/phosphorus contents in feeds and thus potentially decreased nutrient emissions in fish farm effluents.

Rapid Removal of Atmospheric CO2 by Urban Soils.

The measured calcium carbonate content of soils to a depth of 100 mm at a large urban development site has increased over 18 months at a rate that corresponds to the sequestration of 85 t of CO2/ha (8.5 kg of CO2 m(-2)) annually. This is a consequence of rapid weathering of calcium silicate and hydroxide minerals derived from the demolition of concrete structures, which releases Ca that combines with CO2 ultimately derived from the atmosphere, precipitating as calcite. Stable isotope data confirm an atmospheric origin for carbonate carbon, and 14C dating indicates the predominance of modern carbon in the pedogenic calcite. Trial pits show that carbonation extends to depths of ≥1 m. Work at other sites shows that the occurrence of pedogenic carbonates is widespread in artificially created urban soils containing Ca and Mg silicate minerals. Appropriate management of fewer than 12000 ha of urban land to maximize calcite precipitation has the potential to remove 1 million t of CO2 from the atmosphere annually. The maximal global potential is estimated to be approximately 700-1200 Mt of CO2 per year (representing 2.0-3.7% of total emissions from fossil fuel combustion) based on current rates of production of industry-derived Ca- and Mg-bearing materials.

CO2 sequestration in feldspar-rich sandstone: Coupled evolution of fluid chemistry, mineral reaction rates, and hydrogeochemical properties

To investigate CO2 Capture, Utilization, and Storage (CCUS) in sandstones, we performed three 150°C flow-through experiments on K-feldspar-rich cores from the Eau Claire formation. By characterizing fluid and solid samples from these experiments using a suite of analytical techniques, we explored the coupled evolution of fluid chemistry, mineral reaction rates, and hydrogeochemical properties during CO2 sequestration in feldspar-rich sandstone. Overall, our results confirm predictions that the heightened acidity resulting from supercritical CO2 injection into feldspar-rich sandstone will dissolve primary feldspars and precipitate secondary aluminum minerals. A core through which CO2-rich deionized water was recycled for 52days decreased in bulk permeability, exhibited generally low porosity associated with high surface area in post-experiment core sub-samples, and produced an Al hydroxide secondary mineral, such as boehmite. However, two samples subjected to ∼3day single-pass experiments run with CO2-rich, 0.94mol/kg NaCl brines decreased in bulk permeability, showed generally elevated porosity associated with elevated surface area in post-experiment core sub-samples, and produced a phase with kaolinite-like stoichiometry. CO2-induced metal mobilization during the experiments was relatively minor and likely related to Ca mineral dissolution. Based on the relatively rapid approach to equilibrium, the relatively slow near-equilibrium reaction rates, and the minor magnitudes of permeability changes in these experiments, we conclude that CCUS systems with projected lifetimes of several decades are geochemically feasible in the feldspar-rich sandstone end-member examined here. Additionally, the observation that K-feldspar dissolution rates calculated from our whole-rock experiments are in good agreement with literature parameterizations suggests that the latter can be utilized to model CCUS in K-feldspar-rich sandstone. Finally, by performing a number of reactive transport modeling experiments to explore processes occurring during the flow-through experiments, we have found that the overall progress of feldspar hydrolysis is negligibly affected by quartz dissolution, but significantly impacted by the rates of secondary mineral precipitation and their effect on feldspar saturation state. The observations produced here are critical to the development of models of CCUS operations, yet more work, particularly in the quantification of coupled dissolution and precipitation processes, will be required in order to produce models that can accurately predict the behavior of these systems.

The Use of Local Mineral Formulas as a Feed Block Supplement for Beef Cattle Fed on Wild Forages

The present research was carried out to study the diversity of mineral contents of wild forages and to evaluate the beneficial effect of mineral feed supplement formulated by using locally available materials on the performances of beef cattle. The present research was initiated by analyzing mineral contents of wild forages grown around Limau Manis campus areas. Forage samples were collected at 9 sampling areas scattered at plantation, conservation and idle lands. Samples were then analyzed for macro minerals of Ca, P, Mg, K, Na, and S and micro minerals of Co, Cu, Fe, Mn, Se, and Zn. Feeding trial was then conducted to evaluate the beneficial effect of supplementation of local mineral formulas (LMF) produced by using locally available materials on the performances of cattle. Feeding trial was conducted for 6 weeks by using 9 Simmentals cross bred heifers. The trial consisted of 3 treatments, i.e., P1: only grass without supplementation, P2: grass + LMF and P3: grass + mineral premix enriched LMF. Variables measured were: body weight, feed intake, FCR, feed cost and net return. Results showed that the highest macro mineral content of wild forages was Na of about 13.05±2.22 g/kg, varied from 4.1 to 23.8 g/kg, followed by K (11.09±1.43 g/kg) and Ca (6.10±1.09 g/kg DM). Three minerals of Mg, P, and S were found in relatively small concentrations of 1.34±0.30, 0.83±0.23, and 0.17±0.01 g/kg, respectively. Fe, Mn, Cu and Zn were found in relatively high concentrations. The highest concentration of micro minerals was Fe of about 613.8±128.9 mg/kg, followed by Mn of 143.9±23.3 mg/kg, while Zn and Cu were found in relatively small amount of about 31.3±5.5 and 13.2±2.5 mg/kg, respectively. Heifers supplemented with LMF (P2) and mineral premix enriched LMF (P3) showed higher body weight gain, lower FCR and net return than those cattle fed only grass (P1). The most profitable feeding strategy was by supplementation of heifers with mineral premix enriched LMF.

Effects of 25-(OH)D3 on fecal Ca and P excretion, bone mineralization, Ca and P transporter mRNA expression and performance in growing female pigs

A study was conducted to examine the effects of 25-hydroxyvitamin D3 (25-(OH)D3) on fecal Ca and P excretion, bone mineralization, performance and the mRNA expression of intestinal transporter genes in growing female pigs. Sixty-day old gilts (n = 24) with an average initial BW of 23.13 ± 1.49 kg were randomly allocated to a control diet (diet 1) containing wheat/corn/soybean meal and 150 IU kg−1 of Vitamin D3, diet 1 + 50 μg of 25-(OH)D3 kg−1 (diet 2) and diet 1 + 100 μg of 25-(OH)D3 kg−1 (diet 3). The pigs were housed in an individual pen and had ad libitum access to feed and water for 42 days, and BWG and feed intake were measured weekly. Measures of bone mineralization and expression of Ca and P transporters mRNA were analyzed using Dual Energy X-Ray Absortiometry (DEXA) and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. Data were analyzed using GLM procedure of the Statistical Analysis System (SAS Institute version 9.2). Fecal Ca and P concentration were significantly reduced (P ≤ 0.05) in pigs fed diets 2 and 3 compared with the control diet. Supplementation of 25-(OH)D3 did not significantly improve bone mineralization, animal performance and intestinal transporters mRNA expression except for SLC34A1, a sodium-dependent phosphate transporter 1. In conclusion, supplementation of 25-(OH)D3 in swine nutrition may not improve animal performance but has the potential to reduce environmental pollution by increasing dietary Ca and P retention while reducing their excretion.

The geochemistry of trace elements in geothermal fluids, Iceland

Trace element geochemistry was studied in geothermal fluids in Iceland. The major and trace element compositions of hot springs, sub-boiling, and two-phase (liquid and vapor) wells from 10 geothermal areas were used to reconstruct the fluid composition in the aquifers at depth. Aquifer fluid temperatures ranged from 4 to 300°C, pH values between 4.5 and 9.3, and fluids typically contained total dissolved solids <1000ppm, except in geothermal areas that have seawater and seawater-meteoric water mixtures. Trace alkali elements Li, Rb and Cs are among the most mobile elements in aquifer fluids, with concentrations in the range of <1ppb to 3.49ppm Li, <0.01 to 57ppb Cs, and <1ppb to 3.77ppm Rb. Their chemistry is thought to be dominated by rock leaching and partitioning into Na- and K-containing major alteration minerals. Arsenic, Sb, Mo and W are typically present in concentrations in the range of 1–100ppb. They are relatively mobile, yet Mo may be limited by molybdenite solubility. The alkaline earth elements Ba and Sr are quite immobile with concentrations in the range of <0.1–10ppb Ba and <1–100ppb Sr in the dilute fluids, but up to 5.9ppm Ba and 8.2ppm Sr in saline fluids. These elements show a systematic relationship with Ca, possibly due to substitution for Ca in Ca-containing major alteration minerals like calcite, epidote and anhydrite. Incorporation into major Ca-minerals may also be important for Mn. Many metals including Fe, Cr, Ni, Zn, Cu, Co, Pb and Ag have low mobility and concentrations, typically <1ppb for Ag, Cd, Co, Cr, Cu, Ni, and Pb, <10ppb for Zn and<100ppb for Fe, although for some metals higher concentrations are associated with saline fluids. Based on the metals assessed, saturation is approached with respect to many sulfide minerals and in some cases oxide minerals but Cu, Ni and Pb minerals are slightly but systematically undersaturated, and Ag phases significantly undersaturated. Evaluation of mineral-fluid equilibria for these metals is problematic due to their low concentrations, problems associated with assessing the aqueous species distribution by thermodynamic calculations, and uncertainties concerning the exact minerals possibly involved in such reactions. Reaction path calculations, poor comparison of concentrations measured in the samples collected at the wellhead and published downhole data as well as boiling, cooling and mass precipitation calculations suggest removal of many metals due to changes upon depressurization boiling and conductive cooling of the aquifer fluids as they ascend in wells. These results imply that processes such as mass precipitation upon fluid ascent may be highly important and emphasize the importance of considering mass movement in geothermal systems.

Nitrogen and Phosphorus Dynamics in the Waters of the Great Ruaha River, Tanzania

This study assessed the levels of nitrogenous (ammonia, nitrite and nitrate) and phosphate compounds in the water column in the Great Ruaha River (GRR) in response to natural and human pressures. Water were sampled using Teflon capped plastic containers and analysed using standard methods. High levels of ammonia were observed in the Mtera dam and low in the GRR and its tributaries as well as at Ruaha Mbuyuni. Nitrite levels were observed only in Mswiswi and Luwosi tributaries in the upstream and in the Mtera and Ruaha Mbuyuni in the downstream. High levels of nitrite were observed in the Mtera dam probably due to increased microbial activity. Levels of nitrates were high in the Mtera dam and in the Mswiswi and Lunwa tributaries and low in the Little Ruaha, Ruaha Mbuyuni and in other tributaries. Nitrate levels were increasing from the tributaries to the main river and later decreasing at Ruaha Mbuyuni probably indicative of some changes in land cover, land use, soil type and groundwater level. Observed levels of phosphate followed an irregular pattern and were relatively were high probably due to anthropogenic activities and absence of Ca, Mg, Al and Fe minerals that can precipitate phosphate. Levels of nitrogen and phosphorus in the GRR were lower than the US EPA and Health Canada set standards, indicative of a natural source. Principal Component Analysis (PCA) indicate that the nitrite and ammonia are so closely related to each other than to nitrate, indicating probably that most nitrites originate from the nitrification of ammonia than the denitrification of nitrate. Similarly, nitrate and phosphate were observed in the same principal component clearly indicative of the same source, which could be fertiliser application in agricultural fields. However, increasing agricultural and livestock activities as aggravated by increasing human population pose a threat on the future dynamics of the nitrogen and phosphorus in the area.

Structural characterization of the borate mineral inyoite – CaB3O3(OH)5⋅4(H2O)

We have studied the mineral Ca(H4B3O7)(OH)⋅4(H2O) or CaB3O3(OH)5⋅4(H2O) using electron microscopy and vibrational spectroscopy. The mineral has been characterized by a range of techniques including X-ray diffraction, thermal analysis, electron microscopy with EDX and vibrational spectroscopy. Electron microscopy shows a pure phase and the chemical analysis shows the presence of calcium only. The nominal resolution of the Raman spectrometer is of the order of 2cm−1 and as such is sufficient enough to identify separate bands for the stretching bands of the two boron isotopes. Raman and infrared bands are assigned to the stretching and bending modes of trigonal and tetrahedral boron and the stretching modes of the hydroxyl and water units. By using a combination of techniques we have characterized the borate mineral inyoite.