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Toxicological information

Basic toxicokinetics

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Administrative data

Endpoint:
basic toxicokinetics in vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)

Data source

Reference
Reference Type:
review article or handbook
Title:
Concise International Chemical Assessment Document 33 , Barium and Barium Compounds
Author:
World Health Organization
Year:
2001
Bibliographic source:
http://www.inchem.org/documents/cicads/cicads/cicad33.htm

Materials and methods

Test guideline
Qualifier:
no guideline required
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent

Administration / exposure

Details on exposure:
Investigations on inhalation as well as drinking water and feed application are discussed. No data was available for dermal uptake.

Results and discussion

Main ADME resultsopen allclose all
Type:
excretion
Results:
Barium is eliminated mainly in the feces and partly in the urine.
Type:
distribution
Results:
Barium is incorporated into the bone
Type:
absorption
Results:
Barium contained in soluble salts is taken up rapidly. Insolube Barium salts are taken up as well, but amounts are determined by buffering of the hydrochloric acid in the stomach.

Any other information on results incl. tables

Insoluble Barium sulfate and soluble barium chloride were absorbed at "nearly equivalent rates" (based on blood and tissue levels) in rats following a single gavage dose of similar barium concentrations (McCauley & Washington, 1983). Similar concentrations of barium were found in the bones of rats fed diets with equivalent doses of barium chloride or barium from Brazil nuts. McCauley & Washington (1983) suggested that the similarity in absorption efficiency between barium sulfate and barium chloride may have been due to the ability of hydrochloric acid in the stomach to solubilize small quantities of barium sulfate (barium chloride, barium sulfate, or barium carbonate had been administered to the rats at a concentration of 10 mg133Ba/litre in the drinking-water at pH 7.0). This is supported by the finding that barium carbonate in a vehicle containing sodium bicarbonate was poorly absorbed. The buffering capacity of sodium bicarbonate may have impaired the hydrochloric acid-mediated conversion of barium carbonate to barium chloride. The results of these studies suggest that soluble barium compounds and/or barium compounds that yield a dissociated barium ion in the acid environment of the upper gastrointestinal tract have similar absorption efficiencies.

Applicant's summary and conclusion