Bismuth exposure

Bismuth has similar human exposure pathways as lead. Its overall exposure opportunity to the human population is much less than lead since bismuth has seen many fewer uses in industry. The opportunity for exposure from ingestion is low, except in its use in medicines. The general population is not subject to bismuth exposure by direct contact. Bismuth is a byproduct of lead smelting and thus there is human exposure from airborne lead smelting emissions. 

Tin exists in two ahotropic forms white tin (P) and gray tin (a). White tin, the form which is most familiar, crystallizes in the body-centered tetragonal system. Gray tin has a diamond cubic stmcture and may be formed when very high purity tin is exposed to temperatures well below zero. The ahotropic transformation is retarded if the tin contains smah amounts of bismuth, antimony, or lead. The spontaneous appearance of gray tin is a rare occurrence because the initiation of transformation requires, in some cases, years of exposure at —40° C. Inoculation with a-tin particles accelerates the transformation. 

Ra.dia.tlon Shielding. Like lead, bismuth absorbs radiation. Therefore, bismuth ahoys are widely used in the medical industry during radiation therapy. The ahoy is molded to the shape of various organs that are to be shielded. Then the molds are placed between the radiation source and the patient to protect the patient s vital organs from radiation exposure. 

A study was made of the comparative stabilities at various exposures of an upset stomach remedy suspension. This product consisted of a dispersion of bismuth subsalicylate and phenylsalicylate in an aqueous system. Methyl-cellulose and magnesium aluminum silicate were selected as the suspending agents, because the presence of polyvalent metallic ions precluded the use of hydrocolloids affected by these ions. In addition, it was found that methyl-cellulose contributed a demulcent effect. The viscosity, as well as the suspension characteristics of the combination of protective colloids used, was of a synergistic nature. These colloids formed a thixotropic system. The thixotropy undoubtedly aids in stabilizing this system. In order to make this product palatable and impart elegance, color and flavor were added. Sample 1 (with protective colloids) showed no separation, while sample 2 (without... 

Time-weighted average (TWA), 74 215 concentration, 25 372 exposure limit, for tantalum, 24 334 Time-Zero SX-70 film, 79 303, 305-307 Tin (Sn). See Lead-antimony-tin alloys Lead- calcium-tin alloys Lead-lithium-tin alloys Lead-tin alloys, 24 782-800. See also Tin alloys Tin compounds allotropes of, 24 786 analytical methods for, 24 790-792 in antimony alloys, 3 52t atomic structure of, 22 232 in barium alloys, 3 344, 4 12t bismuth recovery from concentrates, 4 5-6... 

III. Eradication of Helicobacter pylori C. This microorganism plays an important role in the pathogenesis of chronic gastritis and peptic ulcer disease. The combination of antibacterial drugs and omeprazole has proven effective. In case of intolerance to amoxicillin (p. 270) or clarithromycin (p. 276), metronidazole (p. 274) can be used as a substitute. Colloidal bismuth compounds are also effective however, the problem of heavy-metal exposure compromises their long-term use. 

Acute toxicity of high-level exposure to bismuth manifests as kidney damage. Chronic low-level exposure to bismuth can result in weakness, joint pain, fever, mental confusion, and difficulty walking. Symptoms usually resolve when exposure is stopped, but can lead to death with ongoing exposure. 

Fig. 7. (a) A HRTEM image of a 40-nm freestanding bismuth nanowire, showing lattice fringes. The amorphous surface layer is bismuth oxide formed upon air exposure of bismuth nanowire, (b) SAED pattern of a single Bi nanowire (Zhang et at, 1999). 

Bismuth (III) iodide prepared as described above consists of very small, black, hexagonal crystals having specific gravity 5.64. At atmospheric pressure this compound sublimes at 439° and decomposes at 500°. It is soluble in liquid ammonia and in absolute ethanol. It is insoluble in cold water but decomposes slowly in hot water. Bis-muth(III) iodide is slowly converted to bismuth(III) oxy-iodide upon extended exposure to the atmosphere. 

Cellular and molecular mechanisms of neurotoxicity are also influenced by the fact that neurons are postmitotic and do not divide. Thus, the capacity for replacement of damaged cells does not exist in the nervous system, whereas most other organ systems have a well-established capacity for regeneration. Many neurotoxins can cause encephalopathy and an important concept in neurotoxicology is the delayed manifestation of symptoms sometimes up to years after the exposure started. Several agents show a lag time between exposure and neurotoxicity. Examples are the organophosphate chemical warfare agents [245], bismuth intoxications [246] and methylmercury... 

Most cancers from radon were produced by radon daughter decay products (polonium - 3 isotopes bismuth - 1 isotope and lead - 3 isotopes). ERR (excessive relative risks) of cancers varied, ranging from 0.002 to 0.08 per working level months (WLM) of 170 h of exposure. One WLM is about 200 pCi per liter in a home and 300 pCi per liter in an imdergroimd mine. Relative risk increases from 1 to 10 at 2,500 WLM and 16 at twice that exposure level (5,000 WLM) in the Colorado cohort (Harley, 2008). 

Treatment and Antidotes Personnel showing some of the symptoms noted above, which might indicate that they were absorbing too much bismuth into the body, should be removed from exposure as soon as possible. Get medical advice. Personnel should be cautioned against careless handling of these materials. 

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