Registration Dossier
Registration Dossier
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EC number: 231-099-0 | CAS number: 7439-91-0
Endpoint summary
Administrative data
Link to relevant study record(s)
Description of key information
For the purposes of human risk assessment, oral absorption of lanthanum metal is estimated at 100%, inhalation absorption is estimated at 100% and dermal absorption is not expected to occur.
Key value for chemical safety assessment
- Bioaccumulation potential:
- no bioaccumulation potential
- Absorption rate - oral (%):
- 100
- Absorption rate - inhalation (%):
- 100
Additional information
Introduction
The substance is a dark grey or silver coloured solid. No experimental studies with animals or humans on absorption, metabolism, distribution, or elimination are available for the substance. However, information is available from existing toxicology studies to infer potential toxicokinetic properties. Systemic availability of lanthanum depends on its ability to be absorbed across body surfaces. A major factor affecting this process is water solubility. Lanthanum readily reacts vigorously with water to form lanthanum hydroxide, La(OH)3, which is reportedly insoluble in water and becomes soluble in acid. Based on the known properties of other rare earth metals (e.g. neodymium) lanthanum would react in the stomach to form LaCl3 which is soluble. The melting point of lanthanum is 920ºC. The substance has a molecular weight of 138.9 g/mol.
Absorption
Oral absorption
Absorption via the oral route is unknown. Therefore, in the absence of information, and unknown effect of the acidity on the stomach, 100% bioavailability is assumed.
Dermal absorption
No studies investigating the absorption through the skin were available. In contact with normal dry skin the bulk metal is unlikely to hydrolyse at a sufficient rate that might allow bioavailability, before it is removed. No dermal absorption is expected to occur.
Inhalation absorption
No inhalation studies are available. For any inhaled particles that make it to the alveoli, hydrolysis and formation of more finely divided colloid of the hydroxide is likely to occur. In the absence of any quantitative or qualitative information on inhalation absorption, 100% absorption is assumed.
Distribution and metabolism
No information is available.
Conclusion
For the purposes of human risk assessment oral absorption of lanthanum metal is estimated at 100%, inhalation absorption is estimated at 100% and dermal absorption is not expected to occur.
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