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Uranium and Grass

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http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V5Y-4G7JXVH-3&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version
=1&_urlVersion=0&_userid=10&md5=6e64f8f35f45d1e83b330bf7cbd1f6b5
Abstract

We assessed the accumulation of uranium (VI) by a bacterium, Bacillus subtilis, suspended in a slurry of kaolinite clay, to elucidate the role of microbes on the mobility of U(VI). Various mixtures of bacteria and the koalinite were exposed to solutions of 8 × 10− 6 M- and 4 × 10− 4 M-U(VI) in 0.01 M NaCl at pH 4.7. After 48 h, the mixtures were separated from the solutions by centrifugation, and treated with a 1 M CH3COOK for 24 h to determine the associations of U within the mixture. The mixture exposed to 4 × 10− 4 M U was analyzed by transmission electron microscope (TEM) equipped with EDS. The accumulation of U by the mixture increased with an increase in the amount of B. subtilis cells present at both U concentrations. Treatment of kaolinite with CH3COOK, removed approximately 80% of the associated uranium. However, in the presence of B. subtilis the amount of U removed was much less. TEM–EDS analysis confirmed that most of the U removed from solution was associated with B. subtilis. XANES analysis of the oxidation state of uranium associated with B. subtilis, kaolinite, and with the mixture containing both revealed that it was present as U(VI). These results suggest that the bacteria have a higher affinity for U than the kaolinite clay mineral under the experimental conditions tested, and that they can immobilize significant amounts of uranium.

http://en.wikipedia.org/wiki/Bacillus_subtilis

Bacillus subtilis is a Gram-positive, catalase-positive bacterium commonly found in soil.[1] A member of the genus Bacillus, B. subtilis has the ability to form a tough, protective endospore, allowing the organism to tolerate extreme environmental conditions. Unlike several other well-known species, B. subtilis has historically been classified as an obligate aerobe, though recent research has demonstrated that this is not strictly correct.[2]
It has also been called Bacillus globigii, Hay bacillus or Grass bacillus.
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1747-5457.1994.tb00150.x

Mineralogical studies of Tertiary subsurface sediments in the Niger Delta have shown that smectite, kaolinite, mixed-layer illite/smectite and illite are the principal clay minerals, with subordinate quantities of chlorite. Clays from the Recent delta have similar mineralogical compositions.
Sediments in the eastern Niger Delta are contributed by rivers which drain the Oban and Bamenda Massifs, and the Tertiary volcanics and Cretaceous sediments of the Benue Trough. Sediments in the central and western delta are derived by weathering of the North, Central and SW Nigerian Basement, and also from Cretaceous sediments which are drained by the Niger/Benue river systems.

Clays are known to fix uranium and many other heavy metals. Several U mines are in illite clay body deposits.
Big Water Africa

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Written by aedh

February 12, 2008 at 11:29 pm

One Response

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  1. […] of Tertiary subsurface sediments in the Niger Delta have shown that smectite, kaolinite, <!–more–> Tagged with: Global Cooling, Niger, Uranium; Bacillus subtilis; Kaolinite; Accumulation; […]

    Uranium and grass « HBMT

    February 12, 2008 at 11:52 pm


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