Ppm Cr Research Articles

Toxic effects of dissolved heavy metals on Desulfovibrio vulgaris and Desulfovibrio sp. strains

Biological treatment of metal-containing wastewaters with sulphate-reducing bacteria (SRB) is an attractive technique for the bioremediation of this kind of medium. In order to design a suitable engineering process to address this environmental problem, it is crucial to understand the inhibitory effect of dissolved heavy metals on these bacteria. Batch studies were carried out to evaluate the toxic effects of several heavy metal ions [Cr(III), Cu(II), Mn(II), Ni(II) and Zn(II)] on two cultures of SRB ( Desulfovibrio vulgaris and Desulfovibrio sp.). The experimental data indicate that SRB show different responses to each metal. At the highest metal concentration tolerated for each metal, the precipitation levels for D. vulgaris were as follows: 24.7%-15 ppm Cr(III), 45%-4 ppm Cu(II), 60%-10 ppm Mn(II), 96%-8.5 ppm Ni(II) and 9%-20 ppm Zn(II). The corresponding values for Desulfovibrio sp. were: 25.5%-15 ppm Cr(III), 71%-4 ppm Cu(II), 66.2%-10 ppm Mn(II), 96.1%-8.5 ppm Ni(II) and 93%-20 ppm Zn(II). Results obtained in batch studies will be taken into account for the subsequent design of a sulphate-reducing bioreactor to reduce levels of heavy metals present in different types of contaminated media.

Distribution of Heavy Metal Concentrations in Surface Sediments in Dubai Creeks, United Arab Emirates

Dubai is developing rapidly and many developmental activities are concentrated around its Creek. The present study reports the lateral distribution of heavy metals and compares it with local historical record of heavy metal concentrations. For this purpose surface sediment samples were collected and analyzed for metal contents, total organic carbon content (TOC), mineralogy and grain size. The percentages of the different grain size fraction of the collected sediments were as follow 65% for sand size, 15% for silt size fraction, and the rest accounted for clay size fraction. The microscopic analyses indicate that the sediment composed mainly from carbonate and quartz with traces of rock fragments. Such mineral composition is not believed to be a potential source of heavy metal. The study found that the average recorded heavy metal concentrations in the collected sediment samples were 87, 96, 127, 38.5, and 279 ppm for Cr, Cu, Ni, Pb, and Zn, respectively. Those values were slightly higher than metal concentrations recoded in 2001 with 1.22 (Cr), 2.5 (Cu), 2.87 (Ni), 0.69 (Pb), and 2.1 (Zn) folds. However, in 2001 and 2003 the measured metal contents, along the creek, were lower than those of the average earth crust. Along the Creek most metals recorded the highest concentrations in the upper reach of the Creek. The distribution of the measured heavy metals was not affected significantly with the TOC values. The present study also documented obvious related point sources of pollution.

A new SR‐TXRF vacuum chamber for ultra‐trace analysis at HASYLAB, Beamline L

AbstractA new vacuum chamber for synchrotron radiation‐induced total reflection x‐ray fluorescence (SR‐TXRF) analysis has been installed at HASYLAB, DESY, Hamburg, beamline L utilizing the translation and rotation stages of the regular microfocus setup for adjustment. The chamber is equipped with an automatic sample loader for 30 mm diameter quartz reflectors for inserting the prepared sample reflectors in the measuring position with high reproducibility. Alternatively, a chuck can be inserted allowing various sizes and shapes of samples to be measured. The fluorescence radiation emitted by the sample was measured by a silicon drift detector (SDD) with a 5 mm2 active area and detection limits of 15 fg have been obtained on a sample containing 100 pg of Ni using an Ni/C multilayer monochromator. Using the Si 111 crystal monochromator also x‐ray absorption near edge structure (XANES) investigations in total reflection geometry on trace elements are feasible. Cr K‐edge XANES measurements of C. avellana L. (hazel) pollen (20 ppm Cr concentration) and on an urban aerosol sample are presented. The Cr content in the pollen amounts to about 20 ppm, Detection limits of Cr were found to be 40 pg for a 30 s measuring time, which seems to be reasonable for performing energy scans for x‐ray absorption fine structure measurements. Further, the setup is suitable to perform angle scans to determine depth profiles of implants in Si wafers. This was tested for ultra‐shallow implants of As in Si. Copyright © 2005 John Wiley & Sons, Ltd.

Geochronology and Petrogenesis of the Cretaceous Antampombato–Ambatovy Complex and Associated Dyke Swarm, Madagascar

The Antampombato–Ambatovy complex is the largest intrusion in the central–eastern part of the Cretaceous flood basalt province of Madagascar, with an exposed surface area of about 80 km2. It has an 40Ar/39Ar incremental heating age of 89·9 ± 0·4 Ma and a U–Pb age of 90 ± 2 Ma. The outcropping plutonic rocks range from dunite and wehrlite, through clinopyroxenite and gabbro, to sodic syenite. A dyke swarm cross-cutting some of the above lithologies (and the nearby Precambrian basement rocks) is formed of picritic basalts, alkali to transitional basalts, benmoreites and rhyolites; some of the latter are peralkaline. A few basaltic dykes have cumulate olivine textures, with up to 26 wt % MgO and 1200 ppm Ni, whereas others have characteristics more akin to those of primitive liquids (9 wt % MgO; Mg-number 0·61; 500 ppm Cr; 200 ppm Ni). These basalts have relatively high TiO2 (2·2 wt %) and total iron (14 wt % as Fe2O3), and moderate contents of Nb (10–11 ppm) and Zr (c. 100 ppm). Initial (at 90 Ma) Sr- and Nd-isotope ratios of the clinopyroxenites and basalt dykes are 0·7030–0·7037 and 0·51290–0·51283, respectively. Syenites and peralkaline rhyolites have Sr- and Nd-isotope ratios of 0·7037–0·7039 and 0·51271–0·51274, respectively. The data suggest derivation of the parental magmas from a time-integrated depleted mantle source, combined with small amounts of crustal contamination in the petrogenesis of the more evolved magmas. The isotopic compositions of the mafic–ultramafic rocks are most similar to those of the mid-ocean ridge basalt (MORB)-like igneous rocks of eastern Madagascar, and suggest the existence of an isotopically ‘depleted’ component in the source of the entire Madagascar province, even though the Antampombato basalts are chemically unlike the lavas and dykes with the same depleted isotopic signature found in western Madagascar. If this depleted component is plume-related, this suggests that the plume has a broadly MORB-source mantle composition. The existence of isotopically more enriched magma types in the Madagascan province has several possible petrogenetic explanations, one of which could be the interaction of plume-related melts with the deep lithospheric mantle beneath the island.

A Comparative Study on Rat Intestinal Epithelial Cells and Resident Gut Bacteria: (I) Effect of Hexavalent Chromium

Toxicants including heavy metals reaching the intestine following ingestion through food and water primarily interact with an ecosystem of eukaryotic and prokaryotic cells. Gut bacteria having a dynamic interrelationship with intestinal epithelial cells are known to play important and specific metabolic, trophic, and protective functions. The present study was undertaken to compare the effects of hexavalent chromium on rat intestinal epithelial cells and the resident gut bacteria following in vitro and in vivo exposures. The survival rate and viability pattern of two types of cells were comparable. Under in vitro conditions, the gut bacteria were quick to reduce Cr (VI) in early time periods, while, at 30 h time, both types of cells showed similar capacity for the reduction of Cr (VI). Chromium intoxication (10 ppm of Cr (VI) in drinking water for 10 weeks) caused significant decrease in membrane alkaline phosphatase and Ca2 +-Mg2 +-ATPase activities of intestinal epithelial cells as well as of three gut bacteria viz. Escherichia coli, Pseudomonas sp, and Lactobacillus sp. Major structural membrane constituents like carbohydrates and phospholipids also showed significant decline in both types of cells. These findings indicate that 10 ppm and higher Cr concentrations may cause toxic insult, resulting in impaired intestinal functional efficacy. It also implies that the gut bacteria can be used at least for preliminary screening of heavy metals gastrointestinal toxicity.

Effects of Dengue Virus Infection on the Spleen of Male Mice Given Hexavalent Chromium with Drinking Water

The present study was undertaken to investigate the effects of dengue virus (DV) infection in male mice given drinking water containing 250 ppm Cr (VI) and the normal control male mice given plain water to drink. On the basis of intake of water in 24 h, the average dose of Cr (VI) in each mouse was 14.8 mg/kg. After 3, 6, and 9 weeks of drinking Cr (VI), a set of five mice from each group were inoculated intracerebrally (ic) with a 1000 × LD50 (100 times the lethal dose that kills 50% mice) dose of DV, and the effects on the spleen were studied at the fourth and eightth day postinoculation. It was observed that Cr (VI) drinking and DV infection led to reduction in the weight of the spleen, but the peak reduction was seen in Cr (VI)-fed mice infected with DV, being 30, 34, and 61% at 3, 6, and 9 weeks respectively. A similar response was seen with respect to the cytotoxic activity of spleen homogenates, phagocytic activity of macrophages, and the mitogenic response of spleen cells to concanavalin A from different groups of animals, being most marked (58 to 60%) at the ninth week of Cr (VI) drinking. This shows a summation of adverse effects of DV infection in mice preexposed to Cr (VI).

A multicommuted flow system for the determination of copper, chromium, iron and lead in lubricating oils with detection by flame AAS

In this work, a flow analysis procedure for the determination of copper, chromium, iron and lead in lubricating oils using flame AAS as detection technique is described. The flow manifold was designed to implement the multicommutation approach and it comprised three 3-way solenoid valves controlled by a personal computer. The flow system presented allowed to process the oil samples to determine wear metals without any prior preparation. Aiming to assess accuracy the results were compared with those obtained by manual procedure using flame AAS. Applying the joint-confidence ellipse test, no significant difference at the 95% confidence level was observed. Other profitable features such as a sample throughput of 50 determinations per hour; relative standard deviations ( n = 5) below 2% for Cu, and below 8% for Cr, Fe and Pb; and linear responses in the range 0–40 ppm (w/w) (Cu, Fe) and 0–15 ppm (w/w) (Cr, Pb) were also achieved.

Toxicity of chromium and heptachlor epoxide on liver of Rana kl. esculenta: A morphological and histochemical study

Over the last 50 years, many species of amphibians have declined markedly, and even become extinct throughout the world. The cause of this is not clear, and several factors may be involved, including exposure to contaminants. The effects of some pollutants (i.e., chromium and heptachlor epoxide) on the green frog (.Rana kl. esculenta) were assessed experimentally, using morpho‐histological techniques. At the lowest doses used (0.5 ppm for Cr, 4 ppb ‐ 40 ppb for heptachlor epoxide), the hepatocytes showed no relevant structural or functional changes. The highest dose (5 ppm for chromium and 400 ppb for heptachlor epoxide) proved to affect the hepatocytes, as revealed mainly by intense ROS reactivity and by increased SDH activity. In addition, relevant variations in melanin content and distribution, as well as in hemo‐siderin deposits, were observed in melanomacrophages. These cells also showed an intense dose‐dependent reactivity for both acid phosphatase and catalase in the liver of treated animals. In general, the results suggest that the role of the melanomacrophag‐ic component is fundamental, possibly due to the action of melanin pigment and to catalase activity towards hepatocytes in detoxification. The 50 ppm dose of chromium was lethal.

Determination of trace amounts of Mn, Al, Si and Cr in Fe-based alloys by radio-frequency-powered glow-discharge optical emission spectrometry associated with the bias-current conduction method

In an r.f. glow-discharge plasma, a d.c. bias current can be introduced by connecting an electric circuit comprising a low-pass filter and a variable resistor. The bias current promotes the emission excitations in the plasma, leading to an improvement of the detection power in the optical-emission spectrometry. By conducting a bias current of 27 mA, the emission intensities of the atomic resonance lines were several-times larger than those obtained with conventional r.f.-powered plasmas. The detection limits for the determination of alloyed elements in Fe-based low-alloyed standard samples were estimated to be 2 ppm Mn for Mn I 403.08 nm, 2 ppm Al for Al I 396.15 nm, 7 ppm Si for Si I 288.158 nm, and 8 ppm Cr for Cr I 425.43 nm.

Desempenho e resposta metabólica de bezerros recebendo dietas suplementadas com cromo

Quatorze bezerros com quatro meses de idade, foram distribuídos em dois tratamentos, sendo um controle e um com suplementação de 0,4 mg de cromo orgânico por kg/M.S de ração basal. A ração basal foi constituída de 52% de feno de coastcross e 48% de concentrado à base de fubá de milho e soja extrusada, e foi oferecida ao animais durante 98 dias. Foi efetuado o controle diário da ingestão de alimentos. Na última semana foi realizado um teste de tolerância à glicose, com os animais em condições de conforto térmico. Para os grupos controle e tratado , o ganho em peso (1,330 e 1,320 kg/dia), a eficiência alimentar (0,24 e 0,25 kg) e a conversão alimentar (4,13 e 4,07 kg), foram semelhantes. Apesar de o grupo tratado apresentar tendência de eliminar a glicose mais rapidamente, os grupos não diferiram entre si.

Phase-mineral and chemical composition of coal fly ashes as a basis for their multicomponent utilization. 2. Characterization of ceramic cenosphere and salt concentrates

The phase-mineral and chemical composition of ceramic cenosphere (CCCs) and water-soluble salt (WSCs) concentrates recovered from five fly ashes (FAs) produced in four large Spanish thermo-electric power stations was characterized. The CCCs and WSCs were isolated by sink-float separation in water and evaporation of the water-soluble solutions leached from FAs, respectively. The CCCs recovered are in the range 0.2–1.1% and their phase-mineral composition (in decreasing order of significance) commonly includes aluminosilicate glass, calcite, mullite, quartz, cristobalite, char, plagioclase, K-feldspar, dolomite, gypsum, and Fe oxides. The CCCs are enriched in Al, Ca, Ce, Co, Rb, Se and Sr in comparison with the FAs. The WSCs isolated are in the range 0.2–0.6% and their phase-mineral composition (in decreasing order of significance) normally includes gypsum, calcite, bassanite, inorganic amorphous matter, anhydrite, alunite, halite, opal, zeolite, dolomite, ankerite and jarosite. The WSCs are abundant in S and Ca, to a lesser extent in Al, Si, Na, K, Mg, Cl, Fe, P and Ti, and contain trace elements such as Cs, Li, Mn, Ni, Sn and Sr with ppm level, and As, Ba, Cr, Cu, Ge, Mo, Pb, Rb, Sb, Se, V, Zn and Zr with ppb level. Most of the elements studied are depleted and only Ca, Cl, K, Na and S are enriched in WSCs in comparison with the FAs. Significant proportions of Ca, Cl, Na and S (2–29%), and to a lesser extent of Al, Cs, K, Mg, P, Si, Sn and Ti (0.1–1%) were leached from the initial elemental contents in FAs. Some genetic features, properties, possible environmental concern and potential utilization directions related to the CCCs and WSCs are also discussed.

The effect of size on trace metal levels in raft cultivated mussels ( Mytilus galloprovincialis)

Mussels are farmed in the coastal inlets of Galicia by means of floating raft culture. The growth of these bivalves is due to their great capacity to filter the water column, which unfortunately, also exposes them to dangerous contaminants, including heavy metals. Thus, it is imperative that mussels be monitored for metals. Size has sometimes been shown to be an important variable, but contradictory results have been found. In order to monitor metals in raft mussels, it is necessary to compile information regarding the number of size classes according to shell length, which must be taken into account to obtain a representative sampling, as well as the number of sample replicates that must be included. Also, to be considered is the cost incurred by carrying out the collection, preparation and analysis per sample. The purpose of this study is to provide information about the effect of size, indicated by shell length on the metal content of raft mussels. The ability of 10 mussel-pooled samples to discriminate real differences in metal concentration was also studied. In general, a positive relationship between metal content and shell length was observed; a similar relation was found between the weight of soft tissues and shell length. As expected from the similarity encountered between relationships of metal content and dry weight–length, the concentrations of the different metals in the soft tissues would not seem to depend on the shell length. Metal concentrations, in this study, were found to be approximately 45 ppm of Hg, 0.5 ppm of Cd, 0.7 ppm of Pb, 0.5 ppm of Cr, 0.6 ppm of Ni, 8 ppm of As, 5 ppm of Cu and 122 ppm of Zn; on a dry weight basis. No significant differences between metal concentrations at different shell lengths were detected. Another important observation was the high variability observed within one size, indicating poor homogeneity in subgroups of similar size, which must be minimized if the number of samples is not enhanced as indicated by power and size analysis.

Benthic Algae as Monitors of Heavy Metals in Various Polluted Rivers by Energy Dispersive X-Ray Spectrometer

Benthic microalgae assemblages were used as monitors of copper (Cu), zinc (Zn), and chromium (Cr) in various polluted rivers of San-Yeh-Kong, in southern Taiwan, and analyzed using Scanning Electron Microscope and Energy Dispersive X-Ray Spectrometer (SEM-EDS). Under SEM-EDS, the benthic algae from seriously polluted rivers (dominant by the cyanobacteria Oscillatoria chalybea, green algae Euglena acus and diatom Nitzschia palea under light microscopes) revealed the elemental compositions of heavy metals such as Cu, Zn, Cr, Ti, and that of Mg, Al, Si, P, S, Cl, K, Ca, and Fe. In contrast, benthic algae from moderately (dominant by diatoms Cymbella turgidula and Gomphonema globiferm) and lightly polluted river (dominant by diatom Diatoma vulgare) didn't have any heavy metal elements. In addition to the algal samples, unfiltered water and bottom mud were also investigated for comparison. Further experiment involving the benthic algae from seriously polluted station revealed that all dominant species could survive on the 1 mL 60 ppm Cu, 1 mL 60 ppm Zn, and 1mL 60 ppm Cr separately after five days culture. The data of this preliminary study are sufficient to encourage further experimentation into the potential for detecting benthic algae as a bioindicator under SEM-EDS to provide rapid information about water pollution.

TNF- α secretion and macrophage mortality induced by cobalt and chromium ions in vitro-Qualitative analysis of apoptosis

Metal ion toxicity is a major cause for concern in metal–metal hip replacements. A previous study in our laboratory demonstrated that Co 2+ and Cr 3+ induce macrophage apoptosis in vitro at 24 h, with the implication of a caspase-3 pathway. The aim of the present study was to look at the effect of a prolonged incubation time on macrophage response with regards to TNF- α secretion and macrophage mortality, more specifically apoptosis. J774 macrophages were exposed for up to 48 h to 0–10 ppm Co 2+ and 0–500 ppm Cr 3+. ELISA results demonstrated that Co 2+ and Cr 3+ induced a concentration- and time-dependent increase of TNF- α secretion, but a decrease at the highest concentrations of Cr 3+ (350–500 ppm). This decrease was most likely due to a high toxicity of Cr 3+ at such concentrations. Higher levels of TNF- α were observed with Co 2+ than Cr 3+, demonstrating a higher stimulatory effect of this ion. Trypan blue and flow cytometry results demonstrated that both Co 2+ and Cr 3+ ions induce macrophage mortality in a dose- and time-dependent manner. The number of cells decreased when ion concentrations increased, especially at 48 h. In parallel with the TNF- α results, Co 2+ was more toxic than Cr 3+ since the maximal effects were reached with lower concentrations (8–10 ppm vs. 350–500 ppm, respectively). DNA analysis demonstrated that both Co 2+ and Cr 3+ ions induce macrophage apoptosis, with a stronger signal at 24 h than at 48 h, suggesting the presence of more necrosis after 48 h. PARP cleavage, another marker of apoptosis, was observed at both 24 and 48 h, with a maximum intensity at 48 h and with the highest concentrations of ions. In conclusion, this study demonstrates that both Co 2+ and Cr 3+ ions can induce the release of TNF- α and macrophage mortality in a dose- and time-dependent manner. More specifically, Co 2+ and Cr 3+ ions induced apoptosis after both 24 and 48 h incubation, although DNA analysis suggested the presence of necrosis at 48 h. The relative importance of apoptosis and necrosis in the induction of macrophage mortality by these metal ions remains to be investigated.

Retention of chromium by modified Al-Bentonite

Retention of chromium (III) from a tanning wastewater by modified Al-bentonites was studied. One bentonite from San Juan province, Argentina, was used. Al-bentonite was prepared by contact of bentonite with hydrolyzed OH-Al solutions (0.10 M in Al) for 24 hours. The modified Al-bentonites were obtained by: a) treatment with 0.5 M sodium chloride; b) with 0.5 M sodium chloride adjusted at pH 8; and c) treatment with an hexametaphosphate solution after sodium addition. Then, the samples were dried at 100 °C and heated at 500 °C. The chromium (III) retention by samples was carried out in batch system putting in contact the material with a 2000 ppm Cr tannery waste at different times. The retained chromium was characterized by analyzing the supernatant using UV-visible spectroscopy. The different chromium retention was correlated with structural characteristics of the solids.

Selective adsorption of chromium(VI) in industrial wastewater using low-cost abundantly available adsorbents

The removal of poisonous Cr(VI) from industrial wastewater by different low-cost abundant adsorbents was investigated. Wool, olive cake, sawdust, pine needles, almond shells, cactus leaves and charcoal were used at different adsorbent/metal ion ratios. The influence of pH, contact time, metal concentration, adsorbent nature and concentration on the selectivity and sensitivity of the removal process was investigated. The adsorption process was found to follow a first-order rate mechanism and the rate constant was evaluated at 30°C. In the case of wool, the rate constant was the highest (39.6×10−3 min−1) and the cactus leaves gave the lowest value (6.8×10−3 min−1). Langmuir and Freundlich isotherms were applicable to the adsorption process and their constants were evaluated. The thermodynamic equilibrium constant and the Gibbs free energy were calculated for each system. The ΔGo for the absorption by wool (−2.26 kJ mol−1) and that for the cactus leaves (2.8 kJ mol−1) supported the findings that wool was the best among the selected adsorbents for the selective removal of Cr(VI) at pH 2 and an adsorbent concentration of 16 g l−1 at 30°C, for which the removal was 81% out of 100 ppm Cr(VI) after 2 h of stirring. A comparison between a simulated sample containing 100 ppm Cr(VI) and a true wastewater sample containing 100 ppm Cr(VI), 19 ppm Al, 30 ppm Mg, 49 ppm Ca, and 10 ppm B, showed that the adsorption process is satisfactory and selective for Cr(VI).

Effects of supplemental organic chromium on growth, feed efficiency and carcass characteristics of feedlot steers

Effects of supplemental organic chromium (Cr) during the growing and finishing periods on feedlot steer performance and carcass characteristics were measured. One hundred and five English and Continental crossbred steers (283±22.6 kg) were allotted randomly to three dietary treatments: (1) control (basal diet: 1.33 ppm (DM) Cr; (2) basal diet with 0.2 ppm (DM) Cr supplementation; (3) basal diet with 0.4 ppm Cr (DM) supplementation. Chromium was supplied as high Cr yeast in a premix added to the diet at either 0.25 or 0.50% (as fed). Daily gain was lower ( P<0.05) in steers fed the 0.4 ppm Cr supplemented diet than by steers fed the unsupplemented or 0.2 ppm Cr diet (0.96 versus 1.11 and 1.16 kg per day). Gain-to-feed ratio (GF) over the entire period was higher ( P<0.05) for steers fed the control and 0.2 ppm Cr diets than for those fed the 0.4 ppm Cr diet (135 and 129 versus 118 g gain per kg feed). Serum cortisol was largely unaffected by Cr feeding throughout the trial. Steers fed the 0.2 ppm Cr diet had the heaviest ( P<0.05) hot carcass weights, steers fed 0.4 ppm Cr had the lightest and control steer carcass weights were statistically intermediate (315, 276, and 302 kg, respectively). Longissimus muscle area tended ( P=0.08) to be greatest with the 0.2 and 0.4 ppm Cr diet and lowest with the control diet (81.6, 77.9 and 81.3 cm 2, respectively). Marbling score (i.e. intramuscular fat deposition) was lower ( P<0.05) in steers fed the 0.4 ppm Cr diet compared with the control and 0.2 ppm Cr diets (395 versus 472 and 446, respectively). Dressing percent was higher ( P<0.05) with the control and 0.2 ppm Cr diet compared with the 0.4 ppm Cr diet (63.37 and 63.65 versus 62.16). Final USDA yield grade was highest ( P<0.05) with the control and 0.2 ppm Cr diets (2.53 and 2.32 versus 1.56). Feeding supplemental organic Cr at 0.2 ppm improved, or tended to improve, some economically important carcass characteristics. Overall, results support a supplementation level of 0.2 ppm of organic Cr to basal rations of about 1.33 ppm Cr (DM basis) due primarily to improvements in carcass quality.

Characterization of Indian cigarette tobacco and its smoke aerosol by nuclear and allied techniques

Forty brands of tobacco used in Indian cigarettes, 20 brands of bidis (tobacco rolled in wrapper leaves), 15 brands of chewing tobacco and 15 brands of snuff tobacco were analyzed by nuclear and allied techniques. The elements measured into tobacco can be grouped into seven categories from less than 1 ppm to 5% by weight. Concentration level varied from 0.5-5% for (Ca, K, Cl), 400-1500 ppm (Fe), 200-600 ppm (Na), 100-300 ppm (Ti, Mn, Br and Sr), 10-100 ppm (Cu, Zn and Rb), 1-10 ppm (Cr, Ni, Pb and La) and less than 1 ppm (As, Co, Cd, Sb, Hg and Eu). Among the above elements Cr, Ni, As, Cd, Pb, Hg and Sb are considered toxic. The percentage transfer of the elements from cigarette tobacco to smoke particles during smoking was also estimated using a smoking machine and collecting the smoke particles on a filter paper. The results show that Br, Cr, Sb and Zn have high percentage transfer from tobacco to its smoke of the order of 2-15%. Out of these Sb has the highest 15%. Cobalt, Fe and Sc have lowest percentage of transfer of the order of less than 1%. The percent transfer of these elements from tobacco to tobacco smoke is higher in case of bidis (1.5-3.0 times) as compared to cigarettes. In cigarettes also non-filter cigarettes have higher transfer (2-3 times) as compared to filter tip cigarettes.

SALINITY-HEAVY METAL INTERACTIONS IN FOUR SALT-TOLERANT PLANT SPECIES

The concurrent effect of NaCl salinity and heavy metals [cadmium (Cd), chromium (Cr) and nickel (Ni)] on growth, sodium (Na), and heavy metal accumulation was assessed in four salt tolerant plant species. These were: barley (Hordeum vulgare L.), purslane (Portulaca oleracea L.), Inula crithmoides L., and Plantago coronopus L., all of which have documented potential for use in saline agriculture. Plants were grown in perlite and irrigated with salinized and non-salinized nutrient solutions (9 dS m−1 and 18 dS m−1) containing 2 ppm Cd, 4 ppm Cr, 10 ppm Ni, and a non-metal control. Salinity, Cd, and Ni caused a significant decrease in the dry biomass accumulation of P. oleracea, but had no effects on other plant species. Sodium accumulation was highest in P. coronopus and I. crithmoides, indicating pronounced halophytic properties. The presence of heavy metals reduced Na accumulation in H. vulgare and P. oleracea, but had no effect on P. coronopus and I. crithmoides, indicating that the Na-heavy metal interaction is plant-specific. Metal accumulation in the four plant species was generally enhanced by the 9 dS m−1 treatment, but not by the 18 dS m−1 treatment. This could indicate the presence of an ionic exclusion mechanism operating at high salinity levels that would operate indiscriminately on Na as well as on Cd, Cr, and Ni

Effects of Organic Chromium on Protein Synthesis and Glucose Uptake in Ruminants11Approved by the Dean of the College of Agricultural Sciences and Natural Resources, publication no. T-5-410.

In vitro glucose uptake and protein synthesis were measured using serum from feedlot steers fed diets supplemented with organic Cr (OCr); glucose clearance was studied using sheep as a model. Treatments investigated for glucose uptake and protein synthesis were 1) control (0 ppm supplemental Cr), 2) 0.2 ppm supplemental OCr from high Cr yeast, and 3) 0.4 ppm supplemental OCr from high Cr yeast that contained 2,000 ppm Cr (2 mg Cr/g Saccharomyces cerevisiae yeast) added to a 90% concentrate feedlot diet. The form of OCr supplied by high Cr yeast is presumably a glucose tolerance factor (GTF), which potentiates the action of insulin, and consists of Cr3+ centrally bound to or associated with cysteine, glutamate, glycine, and nicotinic acid residues. Serum harvested from steers fed 0.2- and 0.4-ppm OCr diets increased (P<0.05) protein synthesis in primary bovine muscle cultures. Glucose uptake rate by muscle cell cultures was increased (P<0.09) by serum from OCr-supplemented steers. Treatments investigated for glucose clearance by lambs were 1) control (0 ppm supplemental Cr), 2) 0.2 ppm, 3) 0.4 ppm, and 4) 0.8 ppm supplemental OCr from high Cr yeast added to a 85% concentrate finishing diet. Glucose clearance in lambs was improved (P<0.05) by addition of 0.2 and 0.8 ppm OCr to the diet. These results are interpreted to suggest that increased carcass muscling in ruminants fed OCr-supplemented diets is a result of improvements in amino acid uptake and glucose metabolism within muscle cells.