Registration Dossier
Registration Dossier
Data platform availability banner - registered substances factsheets
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Diss Factsheets
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 231-128-7 | CAS number: 7440-19-9
- 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
Link to relevant study record(s)
- Endpoint:
- basic toxicokinetics in vivo
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- not reported
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- study well documented, meets generally accepted scientific principles, acceptable for assessment
- Justification for type of information:
- The surface of samarium metal oxidises on contact with air to form an outer layer of samarium oxide. It is therefore considered appropriate to read across information from samarium oxide to the metal where testing on the metal is not technically possible.
- Reason / purpose for cross-reference:
- other: read-across target
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- Distribution of samarium (Sm) in mice was investigated after inhalation exposure to Sm2O3 particles of 5 µm diameter and 15 mg/m³. Concentrations of Sm were determined by ICP-MS.
- GLP compliance:
- not specified
- Species:
- mouse
- Strain:
- ICR
- Sex:
- male
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Age at study initiation: 6 weeks
- Route of administration:
- inhalation: dust
- Vehicle:
- unchanged (no vehicle)
- Details on exposure:
- During the exposure period, mice inhaled test material in an exposure chamber (Shibata Scientific Technology, Japan), at 15 mg/m³.
- Duration and frequency of treatment / exposure:
- Mice were exposed to test material 7 hours a day, 5 days a week, in accordance with the working conditions of an 8 hour workday with 1 hour rest.
The exposure period was 1 week or 4 weeks, namely total exposure periods were 35 or 140 hours. These groups were expressed as Sm-35 h and Sm-140 h, respectively. - Dose / conc.:
- 15 mg/m³ air
- Control animals:
- yes
- yes, concurrent no treatment
- Details on study design:
- - Terminal procedures:
On the next day and after 4 weeks housing of final exposure, five mice of each group were sacrificed. Lung, liver, kidney, spleen, and inferior branch regions were excised. The tibia bone was isolated by removing muscle and marrow cells.
Organ samples, 0.02-0.1 g were accurately weighed and put into a PFA Teflon bottle, were digested with concentrated nitric acid 0.4 mL and hydrogen peroxide 0.2 mL in a microwave oven. Concentrations of Sm were determined by ICP-MS (Eran6000, PerkinElmer, Japan) at m/z 149 using an external standard. Silicon was measured by ICP-AES (Optima 2100, PerkinElmer Japan). Hematoxylin and eosin stain and transmission electron microscopy with energy dispersive X-ray analysis (TEM 2100, JEOL, Japan) were performed for lung specimens to observe the pathologic characteristics and to check the particles and their chemical composition. - Details on distribution in tissues:
- - Distribution of Sm in organs
The instrumental detection limit of Sm at m/z 149 was single ng/L level and the detection limit in original sample was 0.1 ng/g level, because digested samples were applied to ICP-MS at a state of 100 times dilution of original sample. Unfortunately, an appropriate certified reference material for Sm was not found. In order to evaluate the analytical technique and procedure, the recovery rate of Sm (200 ng) added to 20 mg of the bovine muscle powder (NIST-SRM 8414) was examined, and was 99.2 ± 2.8 %.
The concentrations of handling control and particle exposure control groups were almost the same; scarcely detected. Lung showed the highest concentrations. Average concentrations were different depending on inhalation period and time passed after final inhalation. Individual concentrations, however, varied widely and there was no difference between next day and after 4 weeks for Sm-140 h group, and between Sm-35 h and Sm-140 h groups.
Sm concentrations in liver were much lower than in lung, sub-µg/g in order, were correlated with inhalation period on the next day, and decreased with time passage for Sm-140 h group. Those in kidney and in spleen were lower than in liver. Sm concentrations in bone were expressed per dry weight, because isotonic water used for removing bone marrow cells remained unequally and was deleted. They were dependent on inhalation period; however, their time-dependent change was different from other organs, that is, increased twice in 4 weeks time passage for Sm-35 h group.
The concentrations of Si in lung of particle exposure control groups were about one tenth of Sm, though the inhalation conditions were the same. Those in other organs were very low, the same levels with the handling control, indicating a relative long stay of Sm in lung and bone.
In lung, decreasing ratio of Sm by 4 weeks time passage was 78 % for Sm-35 h group but statistically significant decrease was not observed for Sm-140 h group, suggesting that the half-life time of Sm in lung might change according to dosage.
Observed particle size in lung was less than 0.5 µm. Samarium oxide particles used had a normal distribution of granular size, where ratio of particles smaller than 0.5 µm was only about 1 %. If samarium oxide particles with smaller size were inhaled in mice, larger amounts of Sm would be deposited in lung. Samarium oxide with sub-micrometer or ten nanometer order diameter is commercially available and actually used
as raw materials.
Time-dependent changes of Sm distribution in organ specimens suggested that a part of Sm particles once deposited in lung was solved and transferred to organs.
Solubility of samarium oxide was very low, but was about 0.8 % of samarium oxide in saline in our experiment.
- Distribution of Sm in mouse body
Amounts of Sm in lung, liver, kidney and spleen were calculated, and those in bone were estimated assuming that bone weights were about 10 % of body weights and water contents of 20 %. Amounts in kidney and in spleen were extremely small; less than 1 % of detected amounts, and were neglected. Total amounts of Sm-140 h groups were about 4 times those in Sm-35 h groups, both on the next day and after 4 weeks, though the amounts in the latter period were two-third of those in the former. Distribution pattern of Sm among three organs was similar on the next day, where about 90 % of Sm was deposited in lung. After 4 weeks, Sm ratio in bone increased and became 40 % in Sm-35 h group. These results indicate that inhaled Sm is accumulated in lung and then re-distributed in bone. - Conclusions:
- Samarium oxide particles of 5 µm diameter inhaled by male mice at 15 mg/m³ for 35 or 140 h were deposited mainly in lung. Individual Sm concentrations varied widely and there was no statistically significant difference between next day and after 4 weeks for 140 h exposure group, and between 35 and 140 h exposure groups. Sm was also distributed in liver, kidney, spleen, and bone, though the concentrations were much lower than in lung. Sm concentrations in bone of Sm-35 h group were increased after 4 weeks. These results suggest that a part of Sm in lung was transported to other organs via the blood flow, and that bone was the accumulating organ of the inhaled Sm.
- Executive summary:
Distribution of samarium (Sm) in mice was investigated after inhalation exposure to samarium oxide particles of 5 µm diameter and 15 mg/m³.
Mice were exposed to test material 7 hours a day, 5 days a week, in accordance with the working conditions of an 8 hour workday with 1 hour rest.
The exposure period was 1 week or 4 weeks, namely total exposure periods were 35 or 140 hours. These groups were expressed as Sm-35 h and Sm-140 h, respectively.
On the next day and after 4 weeks housing of final exposure, five mice of each group were sacrificed. Lung, liver, kidney, spleen, and inferior branch regions were excised. The tibia bone was isolated by removing muscle and marrow cells.
Organ samples, 0.02-0.1 g were accurately weighed and were digested with concentrated nitric acid and hydrogen peroxide. Concentrations of Sm were determined by ICP-MS. Haematoxylin and eosin stain and transmission electron microscopy with energy dispersive X-ray analysis were performed for lung specimens to observe the pathologic characteristics and to check the particles and their chemical composition.
Under the conditions of the study, samarium oxide particles were deposited mainly in lung. Individual Sm concentrations varied widely and there was no statistically significant difference between next day and after 4 weeks for 140 h exposure group, and between 35 and 140 h exposure groups. Sm was also distributed in liver, kidney, spleen, and bone, though the concentrations were much lower than in lung. Sm concentrations in bone of Sm-35 h group were increased after 4 weeks. These results suggest that a part of Sm in lung was transported to other organs via the blood flow, and that bone was the accumulating organ of the inhaled Sm.
- Endpoint:
- basic toxicokinetics in vivo
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Study conducted on read-across material
- Justification for type of information:
- The surface of samarium metal oxidises on contact with air to form an outer layer of samarium oxide. It is therefore considered appropriate to read across information from samarium oxide to the metal where testing on the metal is not technically possible.
- Reason / purpose for cross-reference:
- read-across source
Referenceopen allclose all
Body and organ weights
The growth rates of mice of Sm exposure groups were similar to those of corresponding control groups during inhalation period and following 4 weeks. Relative lung weights of Sm-140 h group on the next day were about 29 % higher than that of corresponding handling control. This increase was temporal and not statistically significant. Significant changes in macro observation, diet and water consumptions, and haematocrit values were not observed in either Sm-35 or Sm-140 h groups during the observation period, suggesting the toxicity of samarium oxide particles is not considerable.
Pathological characteristics of lung and detection of particles
Increase of macrophages was observed in lung specimen of Sm-140 h and Si-140 h groups on the next day, however, was obscure in Sm-35 h, Si-35 h, and in all groups after being kept for 4 weeks. Inflammatory changes and other abnormal signs of lung were not seen in any specimens. Crystals, smaller than 0.5 µm, were detected within and between pulmonary alveolus in lung of Sm-140 h group on the next day and also after 4 weeks though the number was smaller, however, were not detected in lung of Sm-35 h group. These crystals were confirmed to contain Sm by energy dispersive X-ray analysis.
Description of key information
Distribution of Sm following inhalation exposure to samarium oxide powder
Samarium oxide particles of 5 µm diameter inhaled by male mice at 15 mg/m³ for 35 or 140 h were deposited mainly in lung. Individual Sm concentrations varied widely and there was no statistically significant difference between next day and after 4 weeks for 140 h exposure group, and between 35 and 140 h exposure groups. Sm was also distributed in liver, kidney, spleen, and bone, though the concentrations were much lower than in lung. Sm concentrations in bone of Sm-35 h group were increased after 4 weeks. These results suggest that a part of Sm in lung was transported to other organs via the blood flow, and that bone was the accumulating organ of the inhaled Sm.
The surface of samarium metal oxidises on contact with air to form an outer layer of samarium oxide. It is therefore considered appropriate to read across information from samarium oxide to the metal where testing on the metal is not technically possible.
Key value for chemical safety assessment
Additional information
Distribution of Sm following inhalation exposure to samarium oxide powder
Distribution of samarium (Sm) in mice was investigated after inhalation exposure to samarium oxide particles of 5 µm diameter and 15 mg/m³.
Mice were exposed to test material 7 hours a day, 5 days a week, in accordance with the working conditions of an 8 hour workday with 1 hour rest.
The exposure period was 1 week or 4 weeks, namely total exposure periods were 35 or 140 hours. These groups were expressed as Sm-35 h and Sm-140 h, respectively.
On the next day and after 4 weeks housing of final exposure, five mice of each group were sacrificed. Lung, liver, kidney, spleen, and inferior branch regions were excised. The tibia bone was isolated by removing muscle and marrow cells.
Organ samples, 0.02-0.1 g were accurately weighed and were digested with concentrated nitric acid and hydrogen peroxide. Concentrations of Sm were determined by ICP-MS. Haematoxylin and eosin stain and transmission electron microscopy with energy dispersive X-ray analysis were performed for lung specimens to observe the pathologic characteristics and to check the particles and their chemical composition.
Under the conditions of the study, samarium oxide particles were deposited mainly in lung. Individual Sm concentrations varied widely and there was no statistically significant difference between next day and after 4 weeks for 140 h exposure group, and between 35 and 140 h exposure groups. Sm was also distributed in liver, kidney, spleen, and bone, though the concentrations were much lower than in lung. Sm concentrations in bone of Sm-35 h group were increased after 4 weeks. These results suggest that a part of Sm in lung was transported to other organs via the blood flow, and that bone was the accumulating organ of the inhaled Sm.
The surface of samarium metal oxidises on contact with air to form an outer layer of samarium oxide. It is therefore considered appropriate to read across information from samarium oxide to the metal where testing on the metal is not technically possible.
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.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.