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EC number: 242-637-9 | CAS number: 18868-43-4
- 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
Dermal absorption
Administrative data
- Endpoint:
- dermal absorption in vitro / ex vivo
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 14 December 2007 - 6 January 2009
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- other: Guideline conform study, conducted and documented under the principles of GLP.
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 2 009
Materials and methods
Test guidelineopen allclose all
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 428 (Skin Absorption: In Vitro Method)
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- other: OECD Environmental Health and Safety Publications Series on Testing and Assessment No. 28. Guidance Document for the Conduct of Skin Absorption Studies (2004)
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
Test material
- Reference substance name:
- disodium molybdate dihydrate
- IUPAC Name:
- disodium molybdate dihydrate
- Reference substance name:
- 10102-40-6
- Cas Number:
- 10102-40-6
- IUPAC Name:
- 10102-40-6
- Reference substance name:
- Na2MoO4 x 2 H2O
- IUPAC Name:
- Na2MoO4 x 2 H2O
- Details on test material:
- - Name of test material (as cited in study report): sodium molybdate dihydrate
- Molecular formula (if other than submission substance): Na2MoO4 x 2 H2O
- Molecular weight (if other than submission substance): 241.95
- Substance type: inorganic metal salt, dihydrate form
- Physical state: solid, crystalline powder
- Analytical purity: 99.6 - 99.9 %
- Storage condition of test material: dry, closed container, ambient temperature
Constituent 1
Constituent 2
Constituent 3
- Radiolabelling:
- no
Test animals
- Species:
- human
Administration / exposure
- Type of coverage:
- open
- Vehicle:
- water
- Duration of exposure:
- 8 hours and 16 h post-exposure monitoring (continued collection of receptor fluid)
- Doses:
- - Nominal doses: 100 and 500 µg test item per cm².
- Actual doses: 105 and 542 µg sodium molybdate dihydrate per cm², corresponding to 42 and 215 µg molybdenum per cm², respectively.
- Dose volume: 10 µL/cm² (solution concentrations: 10.51 and 54.2 mg sodium molybdate dihydrate per mL).
- Rationale for dose selection: 100 and 500 µg test item per cm² cover a range of typical and rather worst case dermal loading, which could be expected during industrial handling of powders. - Details on study design:
- Split-thickness human skin membranes were mounted into flow-through diffusion cells. Receptor fluid, physiological saline containing streptomycin and penicillin G, was pumped underneath the skin at a flow rate of ca 1.5 mL/h. The skin surface temperature was maintained at ca 32°C throughout the experiment. A tritiated water barrier integrity test was performed and any human skin sample exhibiting a kp value greater than 3.5 x 10-3 cm/h was excluded from subsequent absorption measurements.
Disodium molybdate dihydrate has a water solubility of ca 650 g/L. Disodium molybdate dihydrate was applied to human skin at two different application rates: ca 100 µg/cm2 and ca 500 µg/cm2 (equivalent to Molybdenum concentrations of ca 39.66 µg/cm2 and ca 198.3 µg/cm2, respectively). The two test preparations were prepared with final concentrations of Disodium molybdate dihydrate of ca 10 mg/mL and 50 mg/mL. These test preparations were applied to the skin mounted in flow through diffusion cells at an application rate of 10 µL/cm2.
Percutaneous absorption was assessed by collecting receptor fluid in 4 hourly fractions from 0 to 24 h post application. At 8 h post application, exposure was terminated by washing the skin surface with a concentrated commercial soap followed by rinsing with a dilute soap solution and drying the skin surface with tissue paper (tissue swabs). At 24 h post application (ie after a 16 h post exposure monitoring period), the underside of the skin was rinsed with receptor fluid. This rinse was added to the 20-24 h receptor fluid collection sample. The skin was then removed from the flow-through diffusion cells, dried and the stratum corneum removed with 20 successive tape strips. The tape strips were pooled in groups of 5 (1-5, 6-10, 11-15 and 16-20, respectively). These samples were despatched to the analytical laboratory Scientifics Limited where they were analysed by inductively coupled plasma-mass spectroscopy (ICP-MS). The laboratory Charles River then calculated the results from the mass of samples collected and the amount of Molybdenum in each analytical sample.
Results and discussion
- Signs and symptoms of toxicity:
- not specified
- Dermal irritation:
- not specified
- Total recovery:
- Recovery of applied dose acceptable: yes (>98%)
Percutaneous absorptionopen allclose all
- Dose:
- 100 µg/cm²
- Parameter:
- percentage
- Absorption:
- 0.21 %
- Remarks on result:
- other: 24 h (8 h exposure + 16 h post-exposure monitoring)
- Remarks:
- Potentially absorbable dose: includes cumulative receptor fluid, skin, and stratum corneum tape strips 6-20. The 5 outermost tape strips are excluded.
- Dose:
- 500 µg/cm²
- Parameter:
- percentage
- Absorption:
- 0.16 %
- Remarks on result:
- other: 24 h (8 h exposure + 16 h post-exposure monitoring)
- Remarks:
- Potentially absorbable dose: includes cumulative receptor fluid, skin, and stratum corneum tape strips 6-20. The 5 outermost tape strips are excluded.
Any other information on results incl. tables
Summary results table:
Test Preparation |
1 |
2 |
||
Target Concentration of [Na2MoO4.2H2O] |
10 mg/mL |
50 mg/mL |
||
Actual Concentration of [Na2MoO4.2H2O] |
10.51 mg/mL |
54.20 mg/mL |
||
Target Concentration of [Molybdenum] |
3.966 mg/mL |
19.83 mg/mL |
||
Actual Concentration [Molybdenum] |
4.17 mg/mL |
21.50 mg/mL |
||
Application Rate of Test Preparation |
10 µL/cm2(9.78 mg/cm2) |
10 µL/cm2(10.34 mg/cm2) |
||
Application Rate of Na2MoO4.2H2O |
105 µg/cm2 |
542 µg/cm2 |
||
Target Application Rate of Molybdenum |
39.66 µg/cm2 |
198.3 µg/cm2 |
||
Actual Application Rate of Molybdenum |
42 µg/cm2 |
215 µg/cm2 |
||
Percentage of Target Application Rate |
105.06% |
108.40% |
||
Distribution of Na2MoO4.2H2O |
% Applied Dose |
µg/cm2 |
% Applied Dose |
µg/cm2 |
Dislodgeable Dose 8 h |
98.89 |
103.89 |
98.49 |
533.83 |
Unabsorbed Dose |
98.95 |
103.96 |
98.54 |
534.10 |
Absorbed Dose |
0.12 |
0.12 |
0.04 |
0.21 |
Dermal Delivery |
0.18 |
0.19 |
0.13 |
0.72 |
Potentially Absorbable Dose |
0.21 |
0.22 |
0.16 |
0.85 |
Mass Balance |
99.13 |
104.15 |
98.68 |
534.81 |
Dislodgeable dose 8 h = skin wash + tissue swab
Unabsorbed dose = dislodgeable dose 8 h + stratum corneum
Absorbed dose = cumulative receptor fluid
Dermal delivery = skin + absorbed dose
Potentially absorbable dose = dermal delivery + stratum corneum tape strips 6 to 20
Mass balance = unabsorbed dose + dermal delivery
Applicant's summary and conclusion
- Conclusions:
- For the purposes of risk assessment, the potentially absorbable dose (the sum of the absorbed dose, skin and stratum corneum tape strips 6 to 20) may be used. This corresponds to 0.21% for the low exposure scenarios (ca 42 µg Mo/cm2) and 0.16% for the high exposure scenarios (ca 215 µg Mo/cm2). This value also accounts for part of the material associated with the stratum corneum and the test was conducted with a highly water soluble form of Molybdenum in an aqueous solution. Thus, these values are considered to represent a conservative estimate.
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