Barium uptake

Lea, D. W. Spero, H. J. 1992. Experimental determination of barium uptake in shells of the planktonic foraminifera Orbulina universa at 2TC. Geochimica et Cosmochimica Acta, 56, 2673-2680. 

Oldendorf WH (1970) Measurement of barium uptake of radiolabeled substances using a tritiated water internal standard. Brain Res 24 372-376... 

Nickel may be a factor in asbestos carcinogenicity. The presence of chromium and manganese in asbestos fibers may enhance the carcinogenicity of nickel (USEPA 1980), but this relation needs to be verified. Barium-nickel mixtures inhibit calcium uptake in rats, resulting in reduced growth (WHO 1991). Pretreatment of animals with cadmium enhanced the toxicity of nickel to the kidneys and liver (USPHS 1993). Simultaneous exposure to nickel and cadmium — an industrial situation... 

In the above mentioned reaction, platinum oxide and palladium on barium sulfate showed no perceptible change in the rate of hydrogen uptake. On the other hand, platinum oxide was selective in the hydrogenation of cyclohexa-2,4-diene-l,2-dicarboxylic acid to 1,4,5,6-tetrahydrophthalic acid140. A similar result may be the favored reduction of a symmetrical disubstituted double bond over a more hindered trisubstituted bond. The retarding effect of additional substitution is demonstrated in the hydrogenation of a trisubstituted double bond in the presence of a tetrasubstituted double bond (equation 53)141. 

Roza and Berman 1971 Schott and McArdle 1974) and is used as an antidote in cases of acute barium poisoning. Calcium and magnesium suppress uptake of barium in vitro in pancreatic islets. Conversely, barium, in low concentrations, stimulate calcium uptake in these cells. Although the data are insufficient to determine the significance of these findings to human health effects, displacement of calcium may be the mechanism by which barium stimulates insulin release (Berggren et al. 1983). 

The uptake of barium by fish and marine organisms is also an important removal mechanism (Bowen 1966 Schroeder 1970). Barium levels in sea water range from 2 to 63 mg/L with a mean concentration of about 13 pg/L (Bowen 1979). Barium was found to bioconcentrate in marine plants by a factor of 1,000 times the level present in the water. Bioconcentration factors in marine animals, plankton, and in brown algae of 100, 120, and 260, respectively, have been reported (Bowen 1966 Schroeder 1970). 

Food Chain Bioaccumulation. There is information that barium bioconcentrates in certain plants and aquatic organisms (Bowen 1966 Schroeder 1970). However, the extent to which plants bioconcentrate barium from soil or to which uptake occurs in terrestrial animals is not well characterized. Further studies on the bioconcentration of barium by plants and terrestrial animals and on the biomagnification of barium in terrestrial and aquatic food chains would be useful to better characterize the environmental fate of barium and define the importance of food chain accumulation as a source of human exposure. 

Moloukhia MK, Ahmed MW. 1979. Kinetics of barium-140 and radium-223 uptake by human bones. Isot Radiat Res 11 41 -49. 

M. Baxter and T. Jensen (1980b). Uptake of magnesium, strontium, barium and manganese by Plectonema boryanum with special reference to polyphosphate bodies. Protoplasma, 104, 81-89. 

Barium hollandite, Bai.4(Al,Ti)2.28Ti60i6, is an important component of Synroc, a synthetic material developed for the immobilisation of high-level waste from nuclear reactor fuel. The hollandite component of Synroc takes up alkali metal ions such as radioactive Cs by substitution for Ba in the structural channels. This uptake has been studied by Cs MAS NMR which shows a single resonance at 211 ppm from Cs in the channel sites in the absence of paramagnetic ions (Hartman et al. 1998). Replacement of Al by Ti in the channel walls causes the Cs NMR peak to broaden and shift to 640 ppm, and also provides a sensitive means of monitoring the formation of water-soluble CsAlTi04 which, if present, would compromise the aqueous durability of Synroc. 

Cram and Allinger employed in place of the Lindlar catalyst a palladium-on-barium sulfate catalyst poisoned by synthetic quinoline (quinoline from coal tar was unsatisfactory). Thus on hydrogenation of dimethyl 5-decynedioate (I) in methanol the mildly exothermal reaction ceased abruptly after 20 min. with uptake... 

Mercerized sample absorbs barium hydroxide (alkali) to a greater degree than sodium hydroxide and from practical point of view, barium hydroxide is more easy to estimate. The ratio of uptake for this reagent has been referred to barium activity number. 

Samachson J, Dennis J, Fowler R. 1968. Uptake of calcium, strontium, and barium by the surfaces of bone powder and bone mineral. J Dent Res 47(1) 121-126. 

Smith KA (1971) The comparative uptake and translocation by plants of calcium, strontium, barium and radium. I. Bertholletia excelsa (Brazil nut tree) Plant Soil 34 369-379. 

Sulphuric acid is titrated direct using 1 g (precautions should be taken with concentrated acid during weighing to avoid moisture uptake) with standard alkali to methyl orange or methyl red. 1 ml N = 0-04904 g. The sulphate may be checked by the usual precipitation method with barium chloride. BaSO / 0-4202 -- H,SO. ... 

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