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EC number: 231-137-6 | CAS number: 7440-27-9
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Endpoint summary
Administrative data
Description of key information
Key value for chemical safety assessment
Repeated dose toxicity: via oral route - systemic effects
Link to relevant study records
- Endpoint:
- short-term repeated dose toxicity: oral
- Data waiving:
- other justification
- Justification for data waiving:
- other:
- Justification for type of information:
- Human and/or environmental exposure to elemental Terbium in massive form can be excluded, since at environmental conditions (air/humidity) practically insoluble substances (oxides, hydroxides) are formed immediately on the surface: Any respective investigations would be of no additional merit for the relevant scientific knowledge with regard to human and/or environmental protection.
Even if Terbiumoxide or –hydroxide (from Terbium in powder form) would be dissolved in the gastric juice, oral toxicity of the formed Terbium(III)-ion is insignificant. Throughout transition to the duodenum (pH 8-9), dissolved Tb(III) will be precipitated to insoluble Terbiumhydroxide. It should be noted that the gastrointestinal absorption of soluble Terbium salts is < 1%. It follows from the above that no relevant systemic expo sure takes place which would justify additional testing with experimental animals. Even though orally ingested Terbium particles may have an incompletely oxidized core, insoluble Terbiumhydroxide/-oxide would be formed immediately in contact with air or water after “flaking off” the oxide layer. From a toxicological point of view, oral application of soluble Terbium salts in order to perform testing with experimental animals is scientifically not justifiable since the potential bioavailability of 100 % of the soluble salts (It should be noted that systemic availability of soluble Terbium salts is < 1 %!) would be equated with the extremely low bioavailability of the metal.
Furthermore the permanent magnets production with Terbium alloys takes place under strictly co
ntrolled conditions (vacuum, inert gas; see technological process) in order to ensure the high quality of the permanent magnets. Therefore exposure of humans during production of the magnets is unlikely to occur.
In addition the study is technically not feasible: Application of Terbium in massive form, which would be a prerequisite for toxicological and eco-toxicological studies, is practically not feasible. For this purpose at least Terbium powder would be required (see Annex XI (2)).
The Lanthanide elements own a very high affinity for oxygen; they exhibit the highest free energy for oxide formation of all elements in the periodic table, accounting for the exceptional thermodynamic stability of the oxides. In consequence the metals will react with air, building up an oxide layer on the surface. This implies the technical unfeasibility of exposure to “free” Terbium metal (powder form), which is a prerequisite for the requested biological tests. Appropriate application of „free“ Terbium metal is not possible since the particles would react in contact with water and air. The readily formed oxides and hydroxides are insoluble in water.
Furthermore according to REACH annex V, section 1 "substances which result from a chemical reaction that occurs incidental to exposure of another substance or article to environmental factors such as air, moisture, microbial organisms or sunlight" are exempted from the obligation to register. The ignoble metal Terbium is due to its high reactivity (high reduction potential) with water and air not existent at ambient conditions. In air Terbium metal is converted to Terbium oxide. In contact with water Terbium hydroxide is immediately formed. These reaction products are exempted from REACH registration obligations.
Reference
Endpoint conclusion
- Endpoint conclusion:
- no study available
Additional information
Human and/or environmental exposure to elemental Terbium in massive form can be excluded, since at environmental conditions (air/humidity) practically insoluble substances (oxides, hydroxides) are formed immediately on the surface: Any respective investigations would be of no additional merit for the relevant scientific knowledge with regard to human and/or environmental protection.
Even if Terbiumoxide or –hydroxide (from Terbium in powder form) would be dissolved in the gastric juice, oral toxicity of the formed Terbium(III)-ion is insignificant. Throughout transition to the duodenum (pH 8-9), dissolved Tb(III) will be precipitated to insoluble Terbiumhydroxide. It should be noted that the gastrointestinal absorption of soluble Terbium salts is < 1%. It follows from the above that no relevant systemic expo sure takes place which would justify additional testing with experimental animals. Even though orally ingested Terbium particles may have an incompletely oxidized core, insoluble Terbiumhydroxide/-oxide would be formed immediately in contact with air or water after “flaking off” the oxide layer. From a toxicological point of view, oral application of soluble Terbium salts in order to perform testing with experimental animals is scientifically not justifiable since the potential bioavailability of 100 % of the soluble salts (It should be noted that systemic availability of soluble Terbium salts is < 1 %!) would be equated with the extremely low bioavailability of the metal.
Furthermore the permanent magnets production with Terbium alloys takes place under strictly co
ntrolled conditions (vacuum, inert gas; see technological process) in order to ensure the high quality of the permanent magnets. Therefore exposure of humans during production of the magnets is unlikely to occur.
In addition the study is technically not feasible: Application of Terbium in massive form, which would be a prerequisite for toxicological and eco-toxicological studies, is practically not feasible. For this purpose at least Terbium powder would be required (see Annex XI (2)).
The Lanthanide elements own a very high affinity for oxygen; they exhibit the highest free energy for oxide formation of all elements in the periodic table, accounting for the exceptional thermodynamic stability of the oxides. In consequence the metals will react with air, building up an oxide layer on the surface. This implies the technical unfeasibility of exposure to “free” Terbium metal (powder form), which is a prerequisite for the requested biological tests. Appropriate application of „free“ Terbium metal is not possible since the particles would react in contact with water and air. The readily formed oxides and hydroxides are insoluble in water.
Furthermore according to REACH annex V, section 1 "substances which result from a chemical reaction that occurs incidental to exposure of another substance or article to environmental factors such as air, moisture, microbial organisms or sunlight" are exempted from the obligation to register. The ignoble metal Terbium is due to its high reactivity (high reduction potential) with water and air not existent at ambient conditions. In air Terbium metal is converted to Terbium oxide. In contact with water Terbium hydroxide is immediately formed. These reaction products are exempted from REACH registration obligations.
Justification for classification or non-classification
No relevant systemic exposure of Terbium metal takes place.Therefore no classification is required.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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