From NuGOwiki
The NuGOwiki Metabolite Database is a joint initiative of NuGO and HMDB
| Taxonomy Navigation Box; search by |
|
All Metabolites | Biochemical | Nutritional | Functional | Metabolic Pathways | Diseases | Phenotypes | Physiological Processes | Protein |
| Barium | |
|---|---|
 | |
| Chemical Name | barium |
| Chemical Formula | Ba |
| CAS Number | 7440-39-3 |
| Chemical Information | HMDB04142 |
| Biochemical Taxonomy |
|
| Functional Taxonomy | Not Available |
| Nutritional Taxonomy | Not Available |
| Metabolic Pathways | Not Available |
| Biofluid Location |
|
| Tissue Location | Not Available |
| Normal Biofluid Concentrations |
|
| Normal Tissue Concentrations | Not Available |
| Diseases / Conditions Related to Nutrition |
|
| Other (Monogenic Disorders) | Not Available |
| Abnormal Biofluid Concentrations |
|
| Abnormal Tissue Concentrations | Not Available |
| Physiological Processes | Not Available |
| Authors: | |
| Affiliations: |
Contents |
Introduction
guidelines
Barium is a dense alkaline earth metal that occurs in nature as a divalent cation in combination with other elements. In addition to its natural presence in the Earth's crust, and therefore its natural occurrence in most surface waters, barium is also released to the environment via industrial emissions. The residence time of barium in the atmosphere may be up to several days.
Barium sulfate exists as a white orthorhombic powder or crystals. Barite, the mineral from which barium sulfate is produced, is a moderately soft crystalline white opaque to transparent mineral. The most important impurities are iron(III) oxide, aluminium oxide, silica, and strontium sulfate.
Barite is used primarily as a constituent in drilling muds in the oil industry. It is also used as a filler in a range of industrial coatings, as a dense filler in some plastics and rubber products, in brake linings, and in some sealants and adhesives. The use dictates the particle size to which barite is milled. For example, drilling muds are ground to an average particle diameter of 44 um, with a maximum of 30 percent of particles less than 6 um in diameter.
There is no evidence that barium undergoes biotransformation other than as a divalent cation. The toxicokinetics of barium ions would be expected to be the same as the toxicokinetics of soluble barium salts. Studies in rats using a soluble salt (barium chloride) have indicated that the absorbed barium ions are distributed via the blood and deposited primarily in the skeleton. The principal route of elimination for barium following oral, inhalation, or intratracheal administration is in the faeces. Following introduction into the respira tory tract, the appearance of barium sulfate in the faeces represents mucociliary clearance from the lungs and subsequent ingestion.
In humans, ingestion of high levels of soluble barium compounds may cause gastroenteritis (vomiting, diarrhoea, abdominal pain), hypopotassaemia, hypertension, cardiac arrhythmias, and skeletal muscle paralysis. Insoluble barium sulfate has been extensively used at large doses (450 g) as an oral radiocontrast medium, and no adverse systemic effects have been reported. No experimental data are available on barium sulfate; however, due to the limited absorption of barium sulfate from the gastrointestinal tract or skin, it is unlikely that any significant systemic effects would occur.
The acute oral toxicity of barium compounds in experimental animals is slight to moderate. Intravenous infusion of barium chloride results in increased blood pressure and cardiac arrhythmias.
Barium hydroxide is strongly alkaline and therefore corrosive. Barium nitrate caused mild skin irritation and severe eye irritation in rabbits. The lack of reports of skin or eye irritation in humans, despite its widespread use, suggests that barium sulfate, often used as a contrast medium, is not a strong irritant. Useful information on the sensitization potential of barium compounds was not identified.
The kidney appears to be the most sensitive target organ in rats and mice exposed repeatedly to barium chloride in drinking water. Long term studies of barium exposure in laboratory animals have not confirmed the blood pressure, cardiac, and skeletal muscle effects seen in humans and laboratory animals orally exposed to acutely high levels.
Inhalation exposure of humans to insoluble forms of barium results in radiological findings of baritosis, without evidence of altered lung function and pathology. Information on the toxicity of inhaled barium in animals is limited. Repeated exposure to barium oxide via inhalation may cause bronchitis to develop, with cough, phlegm, and/or shortness of breath. In a limited study, minor histopathological changes were seen in the lungs of rats exposed to barium sulfate at 40 mg/m3 for 5 h/day, 5 days/week, but there was no evidence of fibrogenic potential. Animal studies involving respiratory tract instillation of barium sulfate have shown inflammatory responses and granuloma formation in the lungs; this would be expected with exposure to substantial amounts of any low solubility dust, leading to a change in lung clearance and subsequently to lung effects.
Currently available data indicate that barium does not appear to be a reproductive or developmental hazard, although animal studies are limited. Barium was not carcinogenic in standard National Toxicology Program rodent bioassays. Although no in vivo data are available, in vitro data indicate that barium compounds have no mutagenic potential.
Oral intake from drinking water and food is the most prevalent route of exposure to barium compounds for the general population. For the occupational environment, data from industry in the United Kingdom and predictions made using the Estimation and Assessment of Substance Exposure (EASE) model suggest that exposures can be controlled to less than 10 mg/m3 8 hours time weighted average (total inhalable dust). In some situations, control will be to levels significantly below this value. Short term exposures may be higher than 10 mg/m3 for some tasks.
The critical end points in humans for toxicity resulting from exposure to barium and barium compounds appear to be hypertension and renal function. Using a no observed adverse effect level (NOAEL) in humans of 0.21 mg barium/kg body weight per day, a tolerable intake value of 0.02 mg/kg body weight per day for barium and barium compounds has been developed in this document.
Dissolved barium in aquatic environments may represent a risk to aquatic organisms such as daphnids, but it is apparently of lesser risk to fish and aquatic plants, although data are limited. No adverse effects have been reported in ecological assessments of terrestrial plants or wildlife, although some plants are known to bioaccumulate barium from the soil.
(Concise international chemical assessment document 33; http://www.inchem.org/documents/cicads/cicads/cicad33.htm)
Biological Function
Catabolism
Diseases / Conditions Related to Nutrition
- Alzheimer's patients
- Multiple Sclerosis
- Parkinson's Disease
- patients affected by multiple sclerosis with first demyelinating episode
Other (Monogenic) Disorders