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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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: 235-231-8 | CAS number: 12136-78-6
- 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
Genetic toxicity: in vitro
Administrative data
- Endpoint:
- in vitro cytogenicity / chromosome aberration study in mammalian cells
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 2018
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 2 018
- Report date:
- 2018
Materials and methods
Test guideline
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
- GLP compliance:
- yes (incl. QA statement)
- Type of assay:
- in vitro mammalian chromosome aberration test
Test material
- Reference substance name:
- Molybdenum disilicide
- EC Number:
- 235-231-8
- EC Name:
- Molybdenum disilicide
- Cas Number:
- 12136-78-6
- Molecular formula:
- MoSi2
- IUPAC Name:
- molybdenum disilicide
Constituent 1
- Specific details on test material used for the study:
- Batch number: 15535
Method
Species / strain
- Species / strain / cell type:
- lymphocytes:
- Details on mammalian cell type (if applicable):
- CELLS USED
Human peripheral blood lymphocytes.
For this study (in each experiment) blood was collected only from a single donor to reduce inter-individual variability.
MEDIA USED
Complete Culture Medium:
RPMI 1640 medium supplemented with:
15 % fetal bovine serum (FBS)
100 U/100 µg/mL penicillin/streptomycin solution
0.24 g/mL PHA-L
Also used for the long-term treatment and the post incubation.
Treatment Medium (short-term exposure):
Complete culture medium without FBS.
All incubations were done at 37 °C in humidified atmosphere with 5% CO2.
- Metabolic activation:
- with and without
- Metabolic activation system:
- rat liver microsome preparations (S9 mix)
- Test concentrations with justification for top dose:
- On the basis of the data and the observations from the pre experiment and taking into account the recommendations of the guidelines, the following concentrations were evaluated for microscopic analysis.
Experiment I: without metabolic activation: 0.05, 0.1 and 0.25 mM; with metabolic activation: 0.5, 1 and 1.5 mM
Experiment II: without metabolic activation: 0.01, 0.1, 0.25 and 0.5 mM - Vehicle / solvent:
- Vehicle: DMSO
The solvent was compatible with the survival of the cells and the S9 activity.
Controlsopen allclose all
- Untreated negative controls:
- no
- Negative solvent / vehicle controls:
- no
- True negative controls:
- no
- Positive controls:
- yes
- Positive control substance:
- ethylmethanesulphonate
- Untreated negative controls:
- no
- Negative solvent / vehicle controls:
- no
- True negative controls:
- no
- Positive controls:
- yes
- Positive control substance:
- cyclophosphamide
- Details on test system and experimental conditions:
- Experimental Performance
Treatment
Experiment I: Short-term exposure 4 h (without and with S9 mix)
After 48 h the culture medium was replaced with serum-free medium containing the test item (without metabolic activation) and serum-free medium containing the test item with 50 µL/mL S9 mix (with metabolic activation). After 4 h the cells were spun down by gentle centrifugation for 10 min. The supernatant with the dissolved test item was discarded and the cells were resuspended in PBS. The washing procedure was repeated once as described. After washing, the cells were resuspended in complete cell culture medium. The cells were prepared 24 h after the beginning of the treatment.
Experiment II: Long-term exposure 24 h (without S9 mix):
After 48 h the culture medium was replaced with complete medium (with 15% FBS) containing the test item without S9 mix. The treated cells were prepared at the end of the treatment
Determination of Cell Cycle Disruption
For all experiments, the effect of the test item on cell cycle progression was investigated by addition of BrdU to the cultures. For each experiment the solvent and negative control and the highest dose group were evaluated to reassure the replication time of the cultured lymphocytes. - Evaluation criteria:
- Evaluation of the cultures was performed (according to standard protocol of the "Arbeitsgruppe der Industrie, Cytogenetik") using microscopes with 100x oil immersion objectives. As structural chromosomal aberrations breaks, fragments, deletions, exchanges and chromosomal disintegrations were recorded.
If available, 300 well spread metaphases per concentration and validity controls were scored for cytogenetic damage.
To describe a cytotoxic effect the mitotic index (% cells in mitosis; by counting the number of mitotic cells in 1000 cells) was determined. Additionally the number of polyploid cells was scored.
Results and discussion
Test results
- Species / strain:
- lymphocytes: human peripheral blood lymphocytes
- Metabolic activation:
- with and without
- Genotoxicity:
- negative
- Cytotoxicity / choice of top concentrations:
- cytotoxicity
- Remarks:
- In experiment II without metabolic activation, cytotoxic effects were observed at concentrations of 0.02 mM and higher
- Vehicle controls validity:
- valid
- Untreated negative controls validity:
- valid
- Positive controls validity:
- valid
- Additional information on results:
- The metaphases were prepared 24 h after start of treatment with the test item. The treatment interval was 4 h without and with metabolic activation (experiment I) and 24 h without metabolic activation (experiment II). Duplicate cultures were set up. Per culture 150 metaphases were scored for structural chromosomal aberrations.
The test item was diluted in DMSO and suspended in cell culture medium. Precipitate of the test item was noted at concentrations of 0.25 mM (withoutmetabolic activation) and 1.5 mM (with metabolic activation) and all higher tested concentrations after treatment. In experiment IIwithoutmetabolic activation, precipitation was observed starting at a concentration of 0.5 mM and higher concentrations.
In experiment I without and with metabolic activation, no biologically relevant decrease of the relative mitotic index was noted up to the highest evaluated concentrations of 0.25 mM and 1.5 mM, respectively. In experiment II without metabolic activation, cytotoxic effects were observed at concentrations of 0.02 mM and higher.
In both experiments, no biologically relevant increase of the aberration rates was noted after treatment with the test item without and with metabolic activation. The aberration rates of all dose groups treated with the test item were within the historical control data of the negative control.
In the experiments I and II without and with metabolic activation, no biologically relevant increase in the frequencies of polyploid cells was found after treatment with the test item as compared to the solvent controls.
The Fisher´s exact test was performed to verify the results in the experiment. No statistically significant increase (p < 0.05) of cells with chromosomal aberrations was noted in the dose groups of the test item evaluated in experiment I and II without and with metabolic activation.
The x² Test for trend was performed to test whether there is a concentration-related increase in chromosomal aberrations. No statistically significant increase was observed in all experimental conditions.
EMS (400 and 600 µg/mL) and CPA (5 µg/mL) were used as positive controls and induced distinct and biologically relevant increases of chromosomal aberrations, thus proving the efficiency of the test system to indicate potential clastogenic effects.
Any other information on results incl. tables
Experiments I and II:
Result tables are attched in box "Attached background material"
Applicant's summary and conclusion
- Conclusions:
- Molybdenum disilicide is considered to be non-clastogenic in this chromosome aberration test.
- Executive summary:
In the OECD 473 in vitro chromosomal aberration test and under the experimental conditions reported, the test item Molybdenum disilicide did not induce structural chromosomal aberrations in human lymphocyte cells.
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.