High Levels Of Boron Research Articles

The application of isotopic and elemental analysis to determine the geographical origin of premium long grain rice

Rice samples cultivated in the USA, Europe and Basmati regions have been analysed using Isotope Ratio Mass Spectrometry (IRMS) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Nine key variables (carbon-13, oxygen-18, boron, holmium, gadolinium, magnesium, rubidium, selenium and tungsten) were identified by canonical discriminant analysis as providing the maximum discrimination between rice samples from these regions. High levels of boron (>2500 ppb) were associated with rice samples from America and notably high levels of holmium were found in rice samples from the state of Arkansas. European rice samples generally contained relatively high levels of magnesium and Indian/Pakistani samples were characterised by relatively low oxygen-18 (18O) abundance.

Interactions of boron-toxicity, drought, and genotypes on barley root growth, yield, and other agronomic characters

In areas with high levels of soil boron, symptoms of boron (B) toxicity often appear under droughts. This greenhouse study examined the interactions of B-toxicity, drought, and genotypes on barley (Hordeum vulgare L.) root growth, B-toxicity symptoms, B concentrations of straw, and yield. Plants were grown in tubes 65 cm tall. Three factors were studied: B, water supply, and genotypes. There were 2 B levels, B0 v. B50, in the subsoil (20-60 cm). There were 4 levels of water supply: no drought (control), and early, mid-season, and terminal drought. Two barley lines were compared: Sahara (B-toxicity tolerant) and BOL (drought tolerant, B-toxicity sensitive). Significant B-by-drought interaction was detected in straw B concentration, root growth in subsoil, and straw and biological yield for BOL. Mean root growth in the 40–60-cm soil section was much higher under mid-season drought than under the control. At B50, plants under drought had 1-fold higher straw B concentrations and more B-toxicity symptoms than the control plants. This is the first study to provide data to explain the frequent association of B-toxicity symptoms with droughts in the field. The results clearly showed that tolerance to B-toxicity, as well as drought, is needed in dry areas having high levels of subsoil B.

The fracture toughness and toughening mechanisms of nickel-base wear materials

Nickel-base wear materials are typically used as weld hardfacing deposits, or as cast or hot isostatically pressed (HIP) inserts that provide the needed wear resistance to a base material with the desired mechanical properties. Most nickel-base wear materials contain high levels of chromium, silicon, carbon, and boron, which results in complex microstructures that are comprised of high volume fractions of silicide, carbide, and/or boride phases. The volume fraction of nickel-phase dendrite regions typically ranges from 40 to 70 pct, and these dendrite-phase particles are individually isolated by a matrix of silicide, carbide, and boride phases. The continuous matrix of brittle silicide, carbide, and boride phases results in a low damage tolerance for nickel-base wear materials, which is a concern in applications that involve high stresses, thermal transients, or shock loading. Fatigue crack growth (FCG) and fracture toughness (K IC) testing in accordance with ASTM E399 methods has been used to quantify the damage tolerance of various nickel-base wear materials. Fractographic and microstructure examinations were used to define a generic toughening mechanism for nickel-base wear materials. The toughness of nickel-base wear materials is primarily controlled by the plastic deformation of the nickel-phase dendrites in the wake of a crack moving through the matrix of brittle silicide, carbide, and/or boride phases, i.e., crack bridging. Measured K IC values are compared with calculated K IC values based on the crack-bridging model. Microstructure examinations are used to define and confirm the important aspects of the crack-bridging model. This model can be used to predict the toughness values of nickel-base wear materials and direct processing methods to improve the K IC values.

Preferential translocation of boron to young leaves in Arabidopsis thaliana Regulated by the BOR1 Gene

A mutant of Arabidopsis thaliana, bor1-1 (Noguchi et al. 1997: Plant Physiol., 115, 901–916) requires high levels of boron (B) for normal growth. We analyzed the B-deficiency symptoms of bor1-1 mutant plants in detail. A low B supply retarded the growth of the mutant plants more evidently in leaves than in roots. In particular, cell expansion and formation of air spaces were severely impaired by B deficiency in young rosette leaves. Such defects in growth were correlated with the reduced contents of B in leaves. These defects were not observed when a sufficient amount of B was supplied. Uptake experiments with 10B-enriched tracer B demonstrated that B taken up through roots was preferentially transported to young leaves compared to old leaves in the wild-type plants under a low B supply. Such a preferential transport to young leaves was not evident in the mutant plants. In conclusion, our data demonstrated that in A. thaliana plants B is preferentially transported to young organs under a low B supply and that this transport process is controlled at least in part by the BOR1 gene.

Boron Segregation and Electrical Properties in Polycrystalline SiGeC

ABSTRACTPreviously, it has been reported that PMOS capacitors with heavily boron-doped polycrystalline SiGeC gates are less susceptible to boron penetration than those with poly Si gates [1]. Boron appears to accumulate in the poly SiGeC layers during anneals, reducing boron outdiffusion from the gate despite high boron levels in the poly SiGeC at the gate/oxide interface. In this abstract, we report clear evidence of strong boron segregation to polycrystalline SiGeC layers from poly Si, with boron concentration in poly SiGeC (Ge=25%, C=1.5%) increasing to four times that of adjacent poly Si layers. A separate experiment confirms that this result is not due to any SIMS artifacts. Electrical measurements of heavily in-situ doped single layer samples show that the conductivity of poly SiGeC is similar to poly Si and remains roughly constant with annealing at 800°C. However, in a two-layer sample where the poly SiGeC is initially lightly doped and subsequently heavily doped by diffusion by from an adjacent poly Si layer, conductivity appears lower than in poly Si.

Biodistribution of copper carboranyltetraphenylporphyrins in rodents bearing an isogeneic or human neoplasm.

The biodistributions of carborane-containing copper porphyrins, CuTCP and CuTCPH, have been studied previously in mice bearing subcutaneously implanted mammary carcinomas. We now report biodistributions of those porphyrins in Fischer 344 rats bearing intracranial and/or multiple subcutaneous isogeneic 9L gliosarcomas (9LGS). The porphyrin was given either by i.v. infusion or by multiple i.p. injections. When 190 mg CuTCPH/kg body weight was given to the rats by i.v. infusion, median tissue boron concentrations (microg/g) 3 days after the end of infusion were: 64 in subcutaneous tumor, 13 in intracranial tumor, 1 in blood and 3 in brain. When 450 mg CuTCPH/kg body weight was given to the rats by serial i.p. injections, the median concentrations (microg B/g) 4 days after the last injection were: 117 in subcutaneous tumor, 50 in intracranial tumor, 4 in blood, and 4 in brain. CuTCPH biodistribution was also studied in xenografts of the human malignant gliomas U87 and U373, and of the murine EMT-6 mammary carcinoma and the rat 9LGS, each grown subcutaneously in mice with severe combined immunodeficiency (SCIDs). In SCIDs, median boron concentrations (microg/g) 2 days after the last s.c. injection of a total of 190 mg CuTCPH/kg body weight were: 251 in U373, 33 in U87, <0.6 in blood and <0.5 in brain. Because there were such high boron levels in the U373, and because xenografted U373 is similar to spontaneous intracerebral human glioblastoma multiforme (GBM) microscopically, CuTCPH could prove useful as a boron carrier for boron neutron-capture therapy (BNCT) of GBM and of other human malignant gliomas.

In vivo evaluation of carborane gadolinium-DTPA complex as an MR imaging boron carrier.

The evaluation of the Gd-carborane complex 2 as an MR imaging and boron carrier agent was carried out in vivo using tumor-bearing Donryu rats, MRI, ICP-AES, and alpha-autoradiography. The MR imaging revealed that the carborane Gd-DTPA 2 was metabolized slower in the body than Gd-DTPA 1. The results of the ICP-AES method indicated that compound 2 was incorporated into normal tissues and metabolized quickly, whereas it was not accumulated into tumor or brain tissue. The alpha-autoradiography showed that a high level of boron was obtained in the internal organs and in the necrosis of tumor tissue.

Influence of wastewater vs groundwater on youngCitrus trees

The use of wastewater as an alternative water resource for irrigation needs specific studies to evaluate its effect on different soils and crops. Young Citrus trees have been irrigated with wastewater from a sewage treatment plant during three consecutive seasons and the growth, leaf mineral status and fruit quality measured. Some differences have been found between groundwater and wastewater composition. Sodium ion, chloride ion, organic matter and boron concentrations were always higher in wastewater. In contrast, high nitrate levels were found in groundwater, probably due to aquifer contamination. In all seasons the values of soil-analysed elements were within the optimal ranges for this kind of crop and soil. Levels of sodium, chloride and boron in leaf tissue were below the toxic levels for Citrus. Leaf nitrogen content was in the optimal nutrition range and no significant difference was observed between samples from trees irrigated with wastewater and groundwater. Both growth and fruit quality parameters were unaffected by the high levels of sodium, chloride and boron in wastewater. Collectively our data show that no detrimental effects are found after using wastewater for irrigation of young Citrus trees. More importantly, fertiliser rates could be lowered significantly without reducing yields or affecting leaf nutrient levels when using reclaimed wastewater. Thus reclaimed wastewater appears to be a suitable alternative water resource for irrigation of Citrus trees. © 2000 Society of Chemical Industry

Effects of boron and nitrate on hatching success of amphibian eggs.

As part of a land-application wastewater disposal system in central Pennsylvania, vernal ponds are commonly exposed to wastewater effluent containing high levels of boron and nitrate. We examined the individual effects of these compounds on the eggs of amphibians breeding in these ponds. Wood frog (Rana sylvatica), Jefferson salamander (Ambystoma jeffersonianum), spotted salamander (A. maculatum), and American toad (Bufo americanus) eggs were exposed to boron (0, 50, and 100 mg L-1) and nitrate (0, 10, 25, and 40 mg L-1) under laboratory conditions. There was no difference in the hatching success or proportion of deformed larvae among the four nitrate levels in any of the species. High boron concentrations reduced the hatching success of B. americanus and produced more deformed offspring in R. sylvatica, A. jeffersonianum, and A. maculatum. Deformed R. sylvatica and A. jeffersonianum hatchlings displayed a "curling defect" in which the larvae had a crescent body shape and expressed difficulty in swimming. A. maculatum larvae from high boron treatments displayed a different abnormality, possibly because of longer times to hatching, characterized by a swelling of the thoracic region and altered gill morphology. Although the concentrations of boron and nitrate tested were within the range measured in wastewater effluent, maximum levels of boron and nitrate in breeding ponds were only 1.5 mg L-1 and 26.7 mg L-1 respectively, likely due to rainwater dilution and biological and chemical processes reducing the levels of these compounds in vernal ponds. Nonetheless, these studies are the first to examine the effects of boron and nitrate on amphibian egg hatching success, and to demonstrate that elevated boron concentrations can detrimentally affect the development of amphibian embryos.

Development of boron reduction system for sea water desalination

Since boron has been showing to induce male reproductive impediments in laboratory animals, the 1993 WHO guidelines for drinking water quality set the recommended guideline value at 0.3 mg boron/l based on the NOEL (no-observed-adverse-effect level). Since boron is not effectively removed by the conventional water treatment not only for drinking water and domestic wastewater treatment, the concentration in ambient water as well as drinking water is affected by its consumption such as for soaps and detergents in the catchment area. Boron is also affected by leaching from the surrounding geology, drinking water derived water sources affected by a weak alkali spring contains high level of boron. Since the rejection ratio of boron is extremely less than that of salts in RO membrane system applying to drinking water supply in the areas where scarce a fresh water resources, desalinated water contains higher level of boron than that of WHO drinking water quality guidelines. In order to develop of boron treatment system either fresh water or desalinated water, multi stage RO membrane treatment system has studied by using a pilot plant. The boron rejection of RO membrane depends greatly upon pH and driving pressure of RO process. However, the boron rejection does not depends upon its concentration of raw water. Therefore, it is necessary to apply multi stage RO membrane treatment system for producing a finished water that meets the WHO drinking water quality guideline level of boron. Since the secondary and third RO membrane treat less dissolved salt concentration such as observed in fresh water, the driving pressure of RO process for removing boron can operate at low pressure such as about 0.6 to 1.3 MPa. Therefore, multi stage RO membrane sea desalination process and a low pressure RO process can be recommendable for boron management with a reasonable additional cost in drinking water supply.

An Assessment of Fertility in Boron-exposed Turkish Subpopulations

Relationships between elevated boron intake and fertility were sought by comparing reproduction in the residents of two Turkish villages with high levels of boron in their drinking water (one with 8.5 to 29 mg B/L and the other with 2.05 to 2.5 mg B/L), with three nearby villages with more typical low boron levels (0.03 to 0.40 mg B/L). The two high boron villages were designated as Region I, and the three villages with low boron in the drinking water were designated Region II. In addition to exposure to elevated boron in drinking water, 28.3% of the probands in Region I were employed in borate mining or processing, whereas in Region II, 11.7% were so employed. An observational study was carried out in which the authors compared the reproductive history of families living in Region I with families living in Region II by identifying married adults (referred to as probands) who were able to provide information about their and their spouses’ family pedigrees covering three generations. Probands were identified by home visits and, if ever married, accepted for ascertainment. Evidence of fertility was birth of a living child, and data were obtained about the fertility of the proband generation, their parents’ and also their childrens’ generations. In high-boron villages (Region I), 159 three-generation kindreds containing 1068 families were ascertained and, in low-boron villages (Region II), 154 three-generation kindreds containing 610 families were ascertained. In Region I, 96% of marriages produced at least one child, with primary infertility estimated at 2.34% compared with 96% and 2.62%, respectively, for Region II. There was no significant difference in fertility either between Region I and Region II or between the villages within the Regions. The fertility figures are not different from similar measures of fertility in other parts of Turkey. In Region I, the gender ratio (M:F) of offspring was 0.89, whereas in the Region II villages the gender ratio was 1.04 (NS, χ 2 = 1.335, P > 0.05). It is concluded that at the elevated boron drinking water levels studied, a boron-related effect on reproduction was not found.

Rapid thermal chemical vapor deposition of in situ boron-doped polycrystalline silicon-germanium films on silicon dioxide for complimentary-metal-oxide-semiconductor applications

In situ boron-doped polycrystalline Si1−xGex (x&amp;gt;0.4) films have been formed on the thermally grown oxides in a rapid thermal chemical vapor deposition processor using SiH4-GeH4-B2H6-H2 gas system. Our results showed that in situ boron-doped Si1−xGex films can be directly deposited on the oxide surface, in contrast to the rapid thermal deposition of undoped silicon-germanium (Si1−xGex) films on oxides which is a partially selective process and requires a thin silicon film pre-deposition to form a continuous film. For the in situ boron-doped Si1−xGex films, we observed that with the increase of the germane percentage in the gas source, the Ge content and the deposition rate of the film are increased, while its resistivity is decreased down to 0.66 mΩ cm for a Ge content of 73%. Capacitance-voltage characteristics of p-type metal-oxide-semiconductor capacitors with p+-Si1−xGex gates showed negligible polydepletion effect for a 75 Å gate oxide, indicating that a high doping level of boron at the poly-Si1−xGex/oxide interface was achieved.

Variation in growth, development, and yield of durum wheat in response to high soil boron. I. Average effects

A greenhouse study was conducted to examine how the performance of a group of durum wheat (Triticum turgidum L. var. durum Desf, syn. T. Durum) lines was affected by high soil boron (B) levels in terms of growth, phenological development, and grain yield components. Three soil B levels (hot-water extractable B concentrations of 0·3, 7·1, and 17·4 mg/kg) were set up by mixing soil with boric acid. Foliar symptom scores of B toxicity were taken at the beginning of tillering. Six seedlings were then harvested from each pot for measurement of dry weight and shoot B concentration. Days to heading, numbers of tillers and heads, plant height, flag-leaf area, grain and straw yield, and number of grains were also measured. The high soil B level (17·4 mg/kg) caused symptoms of B toxicity on the foliage, increased shoot B concentrations, retarded growth, and reduced grain yield. Other effects included delayed heading; greater reduction in grain yield than straw yield; severely reduced grain yield per tiller due to an increase in aborted tillers; and decreased 1000-grain weight and number of heads per plant. The moderately high soil B level (7·1 mg/kg) also severely depressed the grain yield of these durum lines.

Variation in growth, development, and yield of durum wheat in response to high soil boron. II. Differences between genotypes

This greenhouse study examined the variation in growth, development, and yield between 9 durum wheat (Triticum turgidum L. var. durum Desf., syn. T. durum) lines in response to high soil boron (B) levels. The lines were selected to represent the range of B-toxicity tolerance in an earlier screening experiment. Three soil B levels (hot-water extractable B concentrations of 0·3, 7·1, and 17·4 mg/kg, designated as B0, B25, and B50, respectively) were set up by mixing different amounts of boric acid with soil. Foliar B-toxicity symptom score, dry weight, and shoot-B concentration were measured at tillering. Agronomic traits and yield were measured. There were differential responses to high soil B levels between the durum lines. The boron×line interaction was significant for B-toxicity symptom score and shoot-B concentration. Based on these 2 characters, and percentage of shoot dry weight and grain yield reduction from B0 to B50, Oued Zenati, Omrabi-5, and Gezira-17 were the most tolerant of the 9 durum lines, yet they were less tolerant to high soil B levels than the tolerant bread-wheat check, Halberd. Nonetheless, until more tolerant materials are developed, these moderately tolerant durum lines could still be useful for areas, like southern Australia, where B toxicity is a problem.

Managing high levels of boron and selenium with trace element accumulator crops

Abstract High concentrations of native extractable boron (B) and selenium (Se) found in some soil environments are detrimental to sustainable agriculture in many parts of the western U.S. As part of a strategy to reduce the impact of this problem, greenhouse and field experiments were conducted to study B and Se uptake in the following plant species used for bioremediation: Astragalus incanus L. (no common name), Creeping saltbush (Atriplex semibaccata R. Br. L.), Old Man saltbush (Atriplex nummularia Lindl. L.), Indian mustard (Brassica júncea Czern L.), tall fescue (Festuca arundinacea Schreb. L.), canola (Brassica napus L.), birdsfoot trefoil (Lotus comiculatus L.), and kenaf (Hibiscus cannabi‐nus L.). In Experiment I, all five plant species, especially Indian mustard, accumulated and lowered soil Se concentrations more effectively when grown in selenate‐treated soil than selenite‐treated soil. In Experiment II, plant tissue concentrations of Se and B in Indian mustard increased proportionally to concentrations of Se and B in water culture. In Experiment III, Indian mustard, canola, and tall fescue accumulated and lowered native soil Se and B concentrations when grown under greenhouse conditions. In Experiment IV, Indian mustard accumulated the highest concentration of native soil Se and kenaf accumulated the highest concentration of native soil B under field conditions. Vegetation management with any of the above plant species should be considered as a bioremediation tool for removing boron or selenium from contaminated soils.

Screening for boron tolerance in wheat (T. aestivum) by solution culture in filter paper

A new screening technique for tolerance to high concentrations of boron, namely a filter paper technique, and a soil experiment were compared to investigate the response of wheat genotypes known to differ in tolerance to high concentrations of boron. Under high boron concentrations in filter papers, the more tolerant genotypes had significantly longer roots than those of the more sensitive genotypes. There was no significant correlation between the root lengths at the control treatment and the other three boron treatments (50, 100, 150 mg B L-1). Thus, the differences in root lengths at the high boron treatments could not be attributed to inherent differences in root growth but to the genetic variation in response to high boron concentrations among varieties. Root lengths at the three boron treatments in filter papers were highly significantly correlated with the three characters determined for plants grown in soil containing high levels of boron, namely the concentrations of boron in the shoots, plant dry weight and plant symptoms, indicating that root length could be used as a selection criterion in a genetic study or breeding program for boron tolerance.

The effect of fly ash/sewage sludge mixtures and application rates on biomass production

Abstract A greenhouse study was conducted to assess the use of a sewage sludge/fly ash mixture in soils for increased growth and uptake of nutrients by Sorghum vulgaris var. sudanense Hitchc. ("sorgrass"), a sorghum‐sudangrass hybrid plant. This experiment was conducted by using four sewage sludge‐to‐fly ash ratios (4:1, 4:2, 4:3, and 4:4) and six application rates of sewage sludge/fly ash mixtures to soil (0, 50, 100, 150, 200, and 400 tons/acre). The data in this study indicated that the availability of elements to plants varied depending on the mixture ratios and the application rates. All ratios of sewage sludge amended with fly ash generally improved plant growth and enhanced yield at application rates of 50–100 tons/acre but showed reduced growth and yield at higher application rates. The decrease in yield at higher application rates was probably due to the assimilation of high levels of boron which is phytotoxic. These various treatments of sewage sludge/fly ash ratios and rates of application often resulted in elevated concentrations of N, P, K, Ca, Mg, Mn, Fe, B, Cu, and Zn in both soil and plants.

The response of Pisum sativum L. germplasm to high concentrations of soil boron

Tolerance to high levels of boron in the soil is an important aspect of the adaptation of crop varieties to southern Australian conditions. This paper reports investigations aimed at exploring the extent of genetic variation in Pisum sativum and at defining appropriate selection criteria for selection for boron tolerance in breeding programs.

Fly ash‐amended compost as a manure for agricultural crops

Abstract Homemade organic compost prepared from lawn grass clippings was amended with fine fly ash collected from a coal‐fired power plant (SRS 484‐D, Savannah River Site, Aiken, SC) to investigate its usefulness as a manure in enhancing nutrient uptake and increasing dry matter yield in selected agricultural crops. Three treatments were compared: five crops (mustard, collard, string beans, bell pepper, and eggplant) were each grown on three kinds of soil: soil alone, soil amended with composted grass clippings, and soil amended with the mixed compost of grass clippings and 20% fly ash. The fly ash‐amended compost was found to be effective in enhancing the dry matter yield of collard greens and mustard greens by 378% and 348%, respectively, but string beans, bell pepper, and eggplant did not show any significant increase in dry matter yield. Analysis of the above‐ground biomass of these last three plants showed they assimilated high levels of boron, which is phytotoxic; and this may be the reason for thei...

A compendium of tissue nutrient concentrations for field-grown potatoes

Current literature was reviewed to evaluate relationships between potato tissue nutrient concentrations and yield. Primary sources (those based on original research) were emphasized to prevent duplicate information. Data were rejected if stage of growth and plant part were not specifically defined. Data that met these criteria were separated by plant part, stage of growth, and nutrient form (soluble versus total nutrient). The information was then compiled to illustrate the range of reported values for each nutrient, stage of growth, and plant part. Values are presented for deficient, low, sufficient, high, and toxic levels of nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, boron, chlorine, copper, iron, manganese, and zinc.