High Levels Of Boron Research Articles

English

The assessment of groundwater is essential for the estimation of suitability of water for safe use. An attempt has been made to study the groundwater at the district level of Punjab, Pakistan. These samples were analyzed for various water quality parameters like pH, color, odor, conductance, total suspended solids, trace metals (Fe, cu, B, Ba, Al, Cr, Cd, Ni, Mn and Se), ionic concentration (HCO3, CO3, Cl, SO4, Na, K, Ca, Mg, NO3, NO2, NH4, F, PO4 and CN) and for microbiological enumeration (total viable count, total and fecal coliforms Escherichia coli, Salmonella spp. and Pseudomonas spp.). The data was analyzed with WHO guidelines/ recommendations. The results of physical analysis indicated that all samples are safe except the groundwater of Kasur and Khanewal District. About 66.67% samples are out of total suspended solids (TSS) limit. Microbiologically, only six groundwater of Punjab districts are found potable according to WHO limits. In the trace metals analysis, highest level of iron was detected in Jhang while the groundwater of three districts were not potable due to high level of boron and nickel but the groundwater of all districts was found safe with respect to Ba, Al and Cr. As far as ionic concentration is concerned, 11 districts were found not to be within WHO limit in the case of bicarbonates, seven in phosphates, five in floride, and eight in calcium and potassium. Only 10 districts fall within the limit of chlorine and all samples showed satisfactory results in the case of CN, CO3, NO2, NO3, Mg, SO4 and NH4. Key words: Groundwater, physicochemical, ionic concentration, traces elements, microbiology, WHO guidelines/recommendations.

Human brains found in a fire-affected 4000-years old Bronze Age tumulus layer rich in soil alkalines and boron in Kutahya, Western Anatolia

Undecomposed human bodies and organs always attracted interest in terms of understanding biological tissue stability and immortality. Amongst these, cases of natural mummification found in glaciers, bog sediments and deserts caused even more attention. In 2010, an archeological excavation of a Bronze Age layer in a tumulus near the Western Anatolia city Kütahya revealed fire affected regions with burnt human skeletons and charred wooden objects. Inside of the cracked skulls, undecomposed brains were discernible. To analyze the burial taphonomy of the rare phenomenon of brain preservation, we analyzed brains, bone, teeth and surrounding soils elements using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Adipocere formation or saponification of postmortem tissue fat requires high levels of alkalinity and especially potassium. Indeed, ICP-MS analysis of the brain, teeth and bone and also of the surrounding soil revealed high levels of potassium, magnesium, aluminum and boron, which are compatible with the famous role of Kütahya in tile production with its soil containing high level of alkalines and tile-glazing boron. Fatty acid chromatography revealed simultaneous saturation of fats and protection of fragile unsaturated fatty acids consistent with soil-presence of both pro-oxidant and anti-oxidant trace metals. Computerized tomography revealed protection of diencephalic, metencephalic and occipital tissue in one of the best-preserved specimens. Boron was previously found as an intentional preservative of Tutankhamen and Deir el Bahari mummies. Here, in natural soil with its insect-repellant, anti-bacterial and fire-resistance qualities it may be a factor to preserve heat-affected brains as almost bioporcellain specimens.

Adsorption of Arsenic from Borated Water Using Mg-Fe-Hydrotalcite (FeHT)

High selectivity and removal capacity for an adsorbate ion are an important factor for the selection of an adsorbent. Hydrotalcite and hydrotalcite-like compounds as layered double hydroxide have received much attention for their potential application as adsorbents in various fields. Iron-based hydrotalcite compounds has a high selectivity for arsenic. Boron mineralization in Emet-Hisarcik region is one of the world's largest reserves of boron. Unlike the other boron mineralizations, it also contains arsenic minerals, which cause arsenic pollution in the surface and ground waters within the surrounding area. These waters have also significant levels of boron as dissolved oxyanion. The groundwaters associated with arsenical boron deposits was reported to contain up to 600 μg/L As ve 1500 mg/L B. Remediation of arsenic and boron pollution in this water is therefore required. In this study, the removal of arsenic from borated waters by Fe-Hydrotalcite (FeHT) as iron-based layered double hydroxide was investigated. The investigations showed that the adsorption of arsenic was not influenced by increasing the boron concentration. Fe- Hydrotalcite was found to remove 98% of arsenic from ground water containing high level of boron with its ability to reduce As levels below the limit (10 μg/L As) set for potable water by World Health Organization (WHO). The results of this study showed that FeHT, can be used as a potent adsorbant for the removal of arsenic from the borated waters.

Selection of Arthrospira platensis strains with productivity in brackish water with high boron levels for commercial production in the Lluta Valley

Adaptation and selection of Arthrospira platensis strains, for cultivation in brackish water with excess boron (B) in the Lluta Valley can become an interesting alternative that would allow to extend these cultures to areas that possess the environmental conditions, but that lack the fresh water needed to do it. Strains TX98 and P88 were evaluated in laboratory conditions with three different media of brackish water and with the white medium, the Zarrouk modified medium (MZM). The growing media with brackish water with a B concentration present in the Lluta River of 20 mgL -1 (B20) and medium with 30 mgL -1 (B30), and 10 mg L -1 of B (B10). The effect of the different media on the growing parameters with a culture temperature of 25 ± 1ºC in the three treatments, strains TX98 and P88 triplicate, Arthrospira platensis , showed tolerance. It was statistically determined that in the growth, the two strains, the three treatments and in the interrelation of both there were significant differences (p -1 (dry weight) in brackish water with medium B20. Therefore, the highest rate of specific growth (μmax) was obtained with the TX98 strain grown in the brackish medium B30 and the lowest duplication time (0.597 days). Cells grown in brackish water with B had a slightly biochemically modified composition with the white, in relation to the protein content, in the cases in which there are differences in the B content, specifically B30 treatment. For the culture with brackish water from the Lluta River, the TX98 strain is recommended with 10 mg of B using a laboratory to pilot scale.

Reprocessing of 10B-contaminated 10Be AMS targets

10Be accelerator mass spectrometry (AMS) is an increasingly important tool in studies ranging from exposure age dating and palaeo-geomagnetism to the impact of solar variability on the Earth’s climate. High levels of boron in BeO AMS targets can adversely impact the quality of 10Be measurements through interference from the isobar 10B. Numerous methods in chemical sample preparation and AMS measurement have been employed in order to reduce the impact of excessive boron rates. We present details of a method developed to chemically reprocess a set of forty boron-contaminated BeO targets derived from modern Antarctic ice. Previously, the excessive boron levels in these samples, as measured in an argon-filled absorber cell preceding the ionisation detector, had precluded routine AMS measurement. The procedure involved removing the BeO+Nb mixture from the target holders and dissolving the BeO in hot concentrated H2SO4. The solution was then heated with HF to remove the boron as volatile BF3 before re-precipitating as Be(OH)2 and calcining to BeO. This was again mixed with niobium and pressed into fresh target holders. Following reprocessing, the samples gave boron rates reduced by 10–100×, which were sufficiently low and similar to previous successful batches of ice core, snow and associated blank samples, thus allowing a successful 10Be measurement in the absence of any boron correction. Overall recovery of the BeO for this process averaged 40%. Extensive testing of relevant processing equipment and reagents failed to determine the source of the boron. As a precautionary measure, a similar H2SO4+HF step has been subsequently added to the standard ice processing method.

Changes in photosynthetic properties and antioxidative system of pear leaves to boron toxicity

Seedlings of the Cuiguan cultivar of the Asian pear ( Pyrus pyrifolia ) were used to study the effects of boron toxicity on leaf photosynthetic properties and lipid peroxidation. The plants were grown hydroponically and treated with four concentrations of boron: 10 (CK), 100, 300 and 500 μmol·L -1 . After 16 weeks of treatment, we measured the leaf contents of boron and chlorophyll (Chl), the net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular carbon dioxide concentration (Ci), the concentrations of malondialdehyde (MDA), H 2 O 2 , ascorbic acid (ASA) and glutathione (GSH) and the enzymatic activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and glutathione reductase (GR). Treatment with high levels of boron significantly increased the boron content of the pear leaves and reduced Chla, Chlb and carotenoid (Car) contents. Boron stress also reduced the Pn and Gs but increased the Ci. Furthermore, the leaf concentrations of MDA and H 2 O 2 increased with increasing concentrations of boron, whereas the enzymatic activities of SOD, APX, CAT and GR and the ASA and GSH levels first increased and then decreased. These results indicate that boron toxicity reduced the photosynthetic capacity of the pear plant, resulting in the accumulation of reactive oxygen species (ROS) and increased membrane lipid peroxidation. Moderate boron stress can therefore improve the vitality of a plant’s ROS scavenging system, but high concentrations will eventually overcome the system. Key words: Pear, boron toxicity, photosynthetic rate, lipid peroxidation.

Boron Contents of Some Wild-Growing Mushrooms Collected from the Vicinity of Boron Mines in Balikesir, Turkey

The aim of the study was to determine the boron contents of some wild-growing mushrooms collected from the vicinity of several boron mines located in Balikesir, Turkey and compare the boron contents of some mushroom and soil samples. The locations of the mushroom samples collected were within the distance of 0-100, 100-500, and 500-1,000 m to the mines. Soil samples were taken from beneath randomly selected fungal fruit bodies. A total of 40 mushroom samples were found in the study area and 37 different species were identified. Among the 40 samples analyzed, the highest boron content was detected to be 273 mg kg(-1) in Suillus collinitus. Also, Tricholoma terreum (69.52 mg kg(-1)), Myxomphalia maura (36.52 mg kg(-1)), Otidea concinna (30.70 mg kg(-1)), Sepultaria arenosa (28.94 mg kg(-1)), Melanoleuca paedida (28.33 mg kg(-1)), and Lycoperdon lividum (28.31 mg kg(-1)) relatively have high levels of boron and these species are proposed as candidates for boron accumulation. The boron contents of the other mushrooms varied and a pattern was observed where the boron content was found to be decreased as the distance from the mines increased.

Role of overexpressed BOR4, a boron exporter, in tolerance to high level of boron in shoots

High boron (B) tolerance is an important trait for crop production in high-B soils. We previously reported that overexpression of BOR4, an Arabidopsis thaliana B exporter, conferred high B tolerance in A. thaliana. This improvement appeared to be mainly due to the decreased B concentrations in roots through BOR4-mediated exclusion of B. In the present study, we describe a novel role of overexpressed BOR4 in shoots for high B tolerance. We compared shoot growth of wild type A. thaliana and transgenic plants moderately overexpressing BOR4 in relation to B concentration in shoots. It was found that growths and chlorophyll accumulation of shoots containing similar levels of B are better in the transgenic plants than the wild type. This finding established that BOR4-overexpressing plants are more capable of expanding leaves and accumulating chlorophyll in the presence of high B in shoot tissues. BOR4-GFP was found to be localized to plasma membrane in leaf epidermis cells. We suggest that overexpressed BOR4 alters B distribution in leaves by exporting B from the cytoplasm to the apoplast, leading to enhancement of high B tolerance in shoots.

Non-equilibrium sorption modeling for boron removal from geothermal water using sorption–microfiltration hybrid method

In this study, the boron removal performance of a hybrid system composed of ground ion exchange resin particles coupled with a microfiltration separation unit was investigated. A non-equilibrium sorption modeling approach was introduced so as to understand the contributions of mass transfer resistances on the effluent stream concentration profiles, as well as on the resin loading scheme of this sorption–microfiltration hybrid system. This modeling approach allowed us to suggest new system operations and/or scale-up processes of sorption–microfiltration hybrid systems. In this study, the highly porous crosslinked boron selective chelating resins Diaion CRB02 and Dowex XUS 43594.00 containing N-methyl-glucamine group were used. Geothermal water that has high levels of boron was fed into the stirred cell element of the microfiltration system. Kinetic behaviour of boron selective resins for boron removal from geothermal water by the microfiltration system was evaluated to investigate the effects of resin particle size, resin concentration, and permeate flow rate.

INCIDENCE OF BORON DEFICIENCY IN BEDDING PLANTS CAUSED BY DROUGHT STRESS OR ABSCICIC ACID APPLICATION

Growers have reported boron (B) deficiency in pansy (Viola ×wittrockiana) plug production, specifically in plugs grown in the high heat and humidity conditions of summer. Past studies have reported that soil moisture has an impact on boron availability. To simulate drought conditions, ‘Dynamite Yellow’ pansy plants were grown in a peat-based substrate which was allowed to dry down to 40, 30 or 20% container capacity (CC), 10 or 20 days after sowing (DAS) or on a continual basis. Boron tissue concentration was not affected by any induced drought stress, with the exception of those allowed to dry to 40% CC 20 DAS, which had higher levels of boron than the control. To simulate a physiological response to drought stress, exogenous abscisic acid (ABA) was applied as a substrate drench or foliar spray at concentrations of 150 or 300 mg L-1 to ‘Dynamite Yellow’ pansy plants grown in a peat-based substrate 10 or 20 DAS. All treatments resulted in lower tissue concentrations of B compared to an untreated control. Plants treated 10 DAS with a substrate drench (300 mg L-1) or a foliar spray (150 mg L-1) and plants treated 20 DAS with a foliar spray (150 or 300 mg L-1) of ABA showed a reduction in transpiration. Plants had lower ratios of transpiration/leaf area when ABA was applied as a 300 mg L-1 substrate drench 10 DAS and as foliar spray at both concentrations at either application time. The lower B tissue concentrations coupled with lower transpiration rates were similar to circumstances in greenhouse production of fall pansy crops. Boron deficiency is most common in August when high temperatures and relative humidity cause the plants to transpire less.

Removal of boron from geothermal water using hydrotalcite

Geothermal water from geothermal plants often contains high levels of boron (B), above the Japanese effluent standard level. To establish an effective utilization system for geothermal resources, boron removal using non-calcined and calcined hydrotalcite was investigated using geothermal water from the Sumikawa geothermal plant in Japan. Calcined hydrotalcite removed large amounts of boron, and changed the solution pH to 12, while non-calcined hydrotalcite removed little boron. Calcined hydrotalcite are also more effectively removed from other anions including Si, As, F−, Cl−, and . The concentrations of boron dropped to below the Japanese effluent standard level of 10 mg L−1 with a 6 h treatment with calcined hydrotalcite. The ability of calcined hydrotalcite to remove boron from geothermal water was almost constant over the temperature range 25–80°C.

The combined effects of salinity and excess boron on mineral ion relations in broccoli

Two plant stress factors, salinity and high levels of boron, often co-occur in natural and agricultural environments. Many investigations have been conducted to document the influence of the combined stresses on crop growth and yield. Only limited information, however, is available concerning the combined effects of the two stresses on mineral ion uptake and partitioning to shoot organs and tissues. Data for this study were obtained from an experiment conducted in greenhouse sand cultures with two water types: (1) a chloride-dominated system, and (2) sulfate-dominated waters characteristic of those present in the San Joaquin Valley of California. Each saline composition treatment was tested at three salinity levels (2, 12, 18 dS m −1) and three B concentrations (0.046, 1.11, 2.22 mM; 0.5, 12, 24 mg L −1). The gradient in B distribution in individual leaves sampled midseason was steep, with less boron accumulating in petioles than in the blades. The highest B concentrations (>100 mmol B kg −1 dry weight) were found in leaf margins of plants grown in the low salinity-high boron treatments. These leaves were cupped upward, an unusual visual symptom characteristic of B toxicity. At final harvest, concentrations of B, Ca, Mg, Na, K, and Cl were highest in the oldest leaves on the broccoli shoots, decreasing acropetally to the heads. Total-P, however, was highest in broccoli heads, decreasing in the older tissues. Leaf-B accumulation was more closely related to salinity rather than to the concentration of Cl in the irrigation waters. Analysis of variance indicated that substrate B had little effect on Cl accumulation in salt-stressed broccoli leaves regardless of water type. No clear cut relationships were evident that would explain the reciprocal effects of B and Cl on crop yields.

Practical B and P doping via SixSnyGe1−x−y−zMz quaternaries lattice matched to Ge: Structural, electrical, and strain behavior

We describe the fabrication of B and P doped SiGeSn ternaries, lattice-matched to Ge, with compositions adjusted to independently tune the band gap. These are deposited at 320–350 °C with superior crystallinity and morphology via in situ reactions of diborane (p-type) and designer P(SiH3)3 and P(GeH3)3 precursors (n-type). Device-level carrier concentrations in the 1019–1020/cm3 range are produced yielding film resistivities and carrier mobilities comparable to those of Ge indicating negligible alloy scattering. High boron levels induce a significant and systematic contraction of the host lattice, which is compensated by an adjustment of the Sn/Si ratio in accord with a simple model based on Vegard’s law, the mismatch of covalent radii of the constituents, and the absolute hydrostatic deformation potentials for the band edges.

Swelling and microstructure of austenitic stainless steel ChS-68 CW after high dose neutron irradiation

Austenitic stainless steel ChS-68 serving as fuel pin cladding was irradiated in the 20% cold-worked condition in the BN-600 fast reactor in the range 56–84 dpa. This steel was developed to replace EI-847 which was limited by its insufficient resistance to void swelling. Comparison of swelling between EI-847 and ChS-68 under similar irradiation conditions showed improvement of the latter steel by an extended transient regime of an additional ∼10 dpa. Concurrent with swelling was the development of a variety of phases. In the temperature range 430–460 °С where the temperature peak of swelling was located, the principal type of phase generated during irradiation was G-phase, with volume fraction increasing linearly with dose to ∼0.5% at 84 dpa. While the onset of swelling is concurrent with formation of G-phase, the action of G-phase cannot be confidently ascribed to significant removal from solution of swelling-suppressive elements such as silicon. A plausible mechanism for the higher resistance to void swelling of ChS-68 as compared with EI-847 may be related to an observed higher stability of faulted dislocation loops in ChS-68 that impedes the formation of a glissile dislocation network. The higher level of boron in ChS-68 is thought to be one contributor that might play this role.

Removal of boron from Balcova geothermal water by ion exchange–microfiltration hybrid process

This study is focused on the application of the ion exchange–submerged microfiltration hybrid process for boron removal from geothermal water containing high level of boron (8–9 mg B/L). The goal of this study is to determine the optimum parameters such as feed flow rate, resin concentration and resin particle size that govern the efficiency of separation process. During the sorption process, 100–200 mL/h of geothermal water was passed through the membrane module at predetermined permeate flow rates. During the short period of operation (2 h) using boron selective ion exchange resin Diaion CRB02, 0.5 mL/min of flow rate for fresh and saturated resin, 4.2 g/L of resin concentration and 45–125 μm of resin particle size range were found as optimum conditions to decrease the boron concentration in water to the permissible level. In case of the longer period of operation (24 h) conducted by Dowex (XUS 43594.00) resin, a permeate flow rate of 1 mL/min, a resin concentration of 2 g/L and an average resin particle size of 0–20 μm were the optimum conditions for boron removal from geothermal water.

Thermomechanical Effects on Aluminum Matrix Composites Reinforced with AlB2 Particles

Aluminum matrix composites (AMCs) reinforced with aluminum diboride (AlB 2) particles are obtained through a casting process. A mixture design experiment combined with split-split plot experiment helped to assess the significance of the effects of cold work on precipitation hardening prior to aging. Both cold work and aging allowed higher microhardness of the composite matrix, which is further increased by higher levels of boron and copper. Microstructure analysis showed a good distribution of reinforcements and revealed a grain subdivision pattern due to cold work. Tensile tests helped corroborate the microhardness measurements. Fracture surface analysis showed a predominantly mixed brittle—ductile mode.

Identification of differentially expressed transcripts from leaves of the boron tolerant plant Gypsophila perfoliata L.

Very recently some of the species of Gypsophila genus collected from the boron rich soils in Turkey were shown to be remarkably tolerant to high levels of boron. A limited amount of boron is necessary for the normal development of plants; however, a high level of boron in soil is generally toxic. Nevertheless, the adaptability of plant species allows them to withstand the presence of extreme amounts of metal ion by various strategies. This study is conducted on highly boron tolerant Gypsophila perfoliata L. collected from a location in the boron mining area. The plant samples were transferred into plant nutritional medium in the presence high; approximately 500 (35 mg/kg), 1,000, and 30 microM (considered normal) boron concentrations. We compared the transcriptome of the plant sample treated with the excess levels of boron to that of the samples grown under normal concentration using differential display PCR (DDRT-PCR) method. Thirty bands showing differential expression levels (presence or absence of bands or varying intensities) in either of approximately 500 or 30 microM B concentrations at varying time points were excised, cloned, and sequenced. Among which, 18 of them were confirmed via quantitative reverse transcription real time PCR (qRT-PCR). We are reporting the first preliminary molecular level study of boron tolerance on this organism by attempting to identify putative genes related in the tolerance mechanism. The gene fragments are consistent with the literature data obtained from a proteomics study and a metabolomics study performed in barley under varying boron concentrations.

Boron removal from aqueous solution by reverse osmosis

Boron is biologically an essential nutrient for many plants but high boron concentrations in irrigation water cause toxic effects whereas low abundances require boron addition to maximize crop yields. High boron levels in drinking water can be also toxic to humans. There is no easy method for the removal of boron from waters and wastewaters. One or more method may be applied according to boron cocentration in medium. For boron removal, main processes that have been studied are (1) precipitation–coagulation; (2) adsorption on oxides, active carbon, cellulose or clay minerals; (3) ion exchange with basic exchanger; (4) use of boron selective resin; (5) solvent extraction; (6) membrane filtration (electrodialysis, reverse osmosis etc.) In this study boron removal by reverse osmosis was examined. First part of this article reviews current studies about boron removal by reverse osmosis. In the second part of study boron removal by reverse osmosis from aqueous solution (5 mg B/L) was investigated and the rejection ratio of boron was obtained as 69%.

Metal reduction and biomineralization by an alkaliphilic metal-reducing bacterium,Alkaliphilus metalliredigens (QYMF)

Microbial metal reduction has the potential for immobilizing toxic metals and radionuclides in diverse environments. Little is known about metal reduction and immobilization under extreme conditions, and only recently bacterial reduction of metals has been demonstrated under extremely alkaline conditions. The objective of this study was to examine metal reduction and mineral formation using an alkaliphilic bacterium,Alkaliphilus metalliredigens (QYMF), isolated from a leachate-pond containing high levels of salt (Na concentration = 440–12,100 mg/L) and boron (2,000–3,000 mg/L) at pH 9.0–10.0. The bacterium was able to use lactate, acetate, and hydrogen as alternative electron donors and Fe(III)-citrate, Fe(III)- ethylenediaminetetraacetate (EDTA), selenate (SeO4 2−), chromate (CrO4 2−), and Co(III)-EDTA as electron acceptors at medium pH=9.5. The reduction of Fe(III)-citrate and Fe(III)-EDTA in the presence of K2HPO4 and boron resulted in the precipitation of vivianite [Fe3(PO4)2·8H2O]. Formation of sparingly soluble iron phosphates, mediated by the alkaliphilic Fe(III)-reducing bacterium, sequestered iron, phosphate, and other metals into more stable and less toxic forms. These results suggest that bioremediation of metal-contaminated alkaline environments may be feasible, and that the process of metal-reduction may occur in alkaline habitats.

Fine mapping and targeted SNP survey using rice-wheat gene colinearity in the region of the Bo1 boron toxicity tolerance locus of bread wheat

Toxicity due to high levels of soil boron (B) represents a significant limitation to cereal production in some regions, and the Bo1 gene provides a major source of B toxicity tolerance in bread wheat (Triticum aestivum L.). A novel approach was used to develop primers to amplify and sequence gene fragments specifically from the Bo1 region of the hexaploid wheat genome. Single-nucleotide polymorphisms (SNPs) identified were then used to generate markers close to Bo1 on the distal end of chromosome 7BL. In the 16 gene fragments totaling 19.6 kb, SNPs were observed between the two cultivars Cranbrook and Halberd at a low frequency (one every 613 bp). Furthermore, SNPs were distributed unevenly, being limited to only two genes. In contrast, RFLP provided a much greater number of genetic markers, with every tested gene identifying polymorphism. Bo1 previously known only as a QTL was located as a discrete Mendelian locus. In total, 28 new RFLP, PCR and SSR markers were added to the existing map. The 1.8 cM Bo1 interval of wheat corresponds to a 227 kb section of rice chromosome 6L encoding 21 predicted proteins with no homology to any known B transporters. The co-dominant PCR marker AWW5L7 co-segregated with Bo1 and was highly predictive of B tolerance status within a set of 94 Australian bread wheat cultivars and breeding lines. The markers and rice colinearity described here represent tools that will assist B tolerance breeding and the positional cloning of Bo1.