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EC number: 231-970-5 | CAS number: 7782-91-4
- 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
Repeated dose toxicity: inhalation
Administrative data
- Endpoint:
- sub-chronic toxicity: inhalation
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 1982 - 1992
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- other: Well-documented publication (including historical control data)
Data source
Reference
- Reference Type:
- publication
- Title:
- Unnamed
- Year:
- 1 997
Materials and methods
Test guideline
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 413 (Subchronic Inhalation Toxicity: 90-Day Study)
- Deviations:
- no
- GLP compliance:
- yes
- Limit test:
- no
Test material
- Reference substance name:
- Molybdenum trioxide
- EC Number:
- 215-204-7
- EC Name:
- Molybdenum trioxide
- Cas Number:
- 1313-27-5
- Molecular formula:
- MoO3
- IUPAC Name:
- molybdenum trioxide
- Details on test material:
- - Name of test material (as cited in study report): Molybdenum trioxide
- Physical state: Powder
- particle size: the sample material was micronised to a MMAD of approximately 1.5 micrometers
- Analytical purity: approx. 99 %
- Impurities (identity and concentrations): Cadmium ≤ 100 ppm; potassium 2400 ppm; and silicon 180 ppm)
- Lot No.: G1220
- Stability: The stability of the bulk chemical was monitored periodically by the study laboratories using atomic absorption spectroscopy and gravimetric analysis. No degradation of the bulk chemical was observed.
- Storage condition of test material: stored under refrigeration when not in use andallowed to warm to room temperature overnight prior to use
- Karl-Fischer water analysis: 0.03 % +/- 0.02 % water
No further information on the test material was stated.
Constituent 1
Test animals
- Species:
- rat
- Strain:
- Fischer 344
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Source: Frederick Cancer Research Center (Frederick, MD)
- Age at study initiation: 6 weeks
- Housing: Individually in stainless steel mesh cages, changed twice weekly; No bedding/cageboard; Chamber filters: HEPA (intake) and charcoal and HEPA (exhaust); Stainless steel racks
- Diet (ad libitum except during exposure): NIH-07 open formula, pellets (Zeigler Brothers, Inc., Gardners, PA)
- Water (ad libitum): Tap water ( City of Vienna water supply)
- Quarantine period: 2 weeks before study; Before initiation of the studies, two male and two female rats were randomly selected for parasite evaluation and gross observation for evidence of disease.
ENVIRONMENTAL CONDITIONS
- Temperature: 20 °C - 31 °C
- Relative humidity: 55 % - 95 %
- Chamber air: 200 L/minute
- Photoperiod (hrs dark / hrs light): 12/12
No further information on the test animals was stated.
Administration / exposure
- Route of administration:
- inhalation: dust
- Type of inhalation exposure:
- whole body
- Vehicle:
- air
- Remarks on MMAD:
- MMAD / GSD: In the range from ca. 1.5 micrometers (analysed on a weekly basis, individual results are given in the full study report)
- Details on inhalation exposure:
- GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
Molybdenum trioxide was generated by Wright dust-feed mechanisms at gear ratios appropriate for each target concentration on top of approximately 1-L elutriators which opened into the top of each chamber. The airborne dust was swept into the chamber by compressor air at 30 psi and 200 L/minute. Chamber air pressure was negative with respect to that of the room.
TEST ATMOSPHERE
Aerosol cocentration monitoring:
Gravimetric samples were obtained during exposure periods from closed-face Gelman DM-450 Metricel filters in each exposure chamber two to six times per day. Samples were analysed for molybdenum content by atomic absorption. A real-time aerosol monitor (RAM) (Model RAM-1; GCA Corp., Bedford, MA) was used to monitor chambers in real time during the exposure periods. Readings were recorded approximately hourly for each chamber and were used to make adjustments to dust generating systems.
Chamber atmosphere characterization:
Particle size distribution in each chamber was determined weekly for 6 or 7 weeks then again in week 11 or 12 during the 13 week study using an Anderson 8-stage cascade impactor with an 11-micron preseparator. An estimation was made of the mass median areodynamic particle diameter and the geometric standard deviation of each set of samples.
For the 13-week study, the time required to achieve 90 % of target concentration at the start of exposure (T90) was 23 minutes. The time required for the concentration to decay to 10 % of target at the end of exposure (T10) was 23 minutes.
No further details on inhalation exposure was stated. - Analytical verification of doses or concentrations:
- yes
- Details on analytical verification of doses or concentrations:
- see "Details on inhalation exposure " for analytical verification of concentrations.
The means of concentration in all chambers during the 13-week studies were within 10 % of the target concentration. - Duration of treatment / exposure:
- 13 weeks
- Frequency of treatment:
- 6.5 hours per day, 5 days per week
Doses / concentrations
- Remarks:
- Doses / Concentrations:
0, 1, 3,10, 30 and 100 mg/m^3
Basis:
nominal conc.
- No. of animals per sex per dose:
- 10 males / 10 females
- Control animals:
- yes
- Details on study design:
- - Dose selection rationale: The doses were selected based on a 14 day inhalation study with rats. Exposure of rats to molybdenum trioxide for 14 days at concentrations of 0, 3, 10, 30, 100, or 300 mg/m^3 had no effect on survival or clinical findings. However, final mean body weights of male and female rats exposed to 300 mg/m^3 were significantly lower than those of the control group. Because of the body weight effects in the 14-day study, rats were expsoed to 0, 1, 3, 10, 30, or 100 mg/m^3 molybdenum trioxide during the 13- week study.
No further details on study design was stated. - Positive control:
- No data
Examinations
- Observations and examinations performed and frequency:
- CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Weekly
DETAILED CLINICAL OBSERVATIONS: No data
BODY WEIGHT: Yes
- Time schedule for examinations: The animals were weighed initally, weekly, and at the end of the studies.
FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No data
FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No data
WATER CONSUMPTION: No data
OPHTHALMOSCOPIC EXAMINATION: No data
HAEMATOLOGY: Yes
- Time schedule for collection of blood: At the end of the 13 week study
- Anaesthetic used for blood collection: Yes, rats were anesthetized with pentobarbital
- Animals fasted: No data
- How many animals: All exposed and control rats
- Parameters examined: Hematocrit, hemoglobin, erythrocyte count, and leukocyte count and differential
CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: At the end of the 13 week study
- Animals fasted: No data
- How many animals: All exposed and control rats
- Parameters examined: Calcium and inorganic phosphorus concentrations; alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, lactate dehydrogenase, and sorbitol dehydrogenase activities
URINALYSIS: No data
NEUROBEHAVIOURAL EXAMINATION: No data
- OTHER: Sperm motility
At terminal sacrifice, sperm samples were collected from 0, 10, 30,, and 100 mg/m^3 rats. The parameters evaluated included:Spermatogenesis, sperm count and motility. For sperm analyses , the left epididymis and testis were isolated and weighed. The tail of the epididymis (cauda epididymis) was then removed from the epididymal body (corpus epididymis) and weighed.
Liver copper analysis:
All rats were evaluated for liver copper burden. Liver tissue was prepared by wet digestion with nitric and perchloric acids for copper analysis by atmomic absorption spectroscopy.
No further information on observations and examinationsperformed and frequency were stated. - Sacrifice and pathology:
- A necropsy was performed on all animals. The brain, heart, right kidney, liver, lung, right testis, and thymus were weighed. A complete histopathologic examination was performed on 0 and 100 mg/m^3 rats.In addition to gross lesions and tissue masses, the tissue examined included: Adrenal gland, brain, clitoral gland, esophagus, eye, femorotibial joint, heart, large intestine (cecum, colon, rectum), small intestine, kidney, larynx, liver, lung, lymph nodes, (mandibular, mediastinal, peribronchial), mammary gland, nose ( all animals in all exposure groups), ovary, pancreas, parathyroid gland, pituitary gland, preputial gland, prostate gland, salivary gland, spinal cord, spleen, sternum, stomach, testis and epididymis, thymus, thyroid gland, trachea, urinary bladder, uterus, and vagina.
- Statistics:
- The probability of survival was estimated by the product-limit procedure of Kaplan and Meier (1958) and is presented in the form of graphs. Statistical analyses for possible dose-related effects on survival used Cox’s (1972) method for testing two groups for equality and Tarone’s (1975) life table test to identify dose-related trends. All reported P values for the survival analyses are two sided.
Analysis of continuous variables:
Two approaches were employed to assess the significance of pair wise comparisons between exposed and control groups in the analysis of continuous variables. Organ and body weight data, which have approximately normal distributions, were analyzed using the parametric multiple comparison procedures of Dunnett (1955) and Williams (1971, 1972). Clinical chemistry, hematology, blood ,olybdenum levels, spermatid evaluations, liver copper levels, and bone density and curvature, which have typically skewed distributions, were analyzed using the nonparametric multiple comparison methods of Dunn (1964) and Shirley (1977). Jonckheere’s test (Jonckheere, 1954) was used to assess the significance of the dose-related trends and to determine whether a trend sensitive test (Williams’ or Shirley’s test) was more appropriate for pair wise comparisons than a test that does not assume a monotonic dose-related trend (Dunnett’s or Dunn’s test). Average severity values were analyzed for significance using the Mann- Whitney U test (Hollander and Wolfe, 1973).
Results and discussion
Results of examinations
- Clinical signs:
- no effects observed
- Mortality:
- no mortality observed
- Body weight and weight changes:
- no effects observed
- Food consumption and compound intake (if feeding study):
- not specified
- Food efficiency:
- not specified
- Water consumption and compound intake (if drinking water study):
- not specified
- Ophthalmological findings:
- not specified
- Haematological findings:
- no effects observed
- Clinical biochemistry findings:
- no effects observed
- Urinalysis findings:
- not specified
- Behaviour (functional findings):
- not specified
- Organ weight findings including organ / body weight ratios:
- no effects observed
- Gross pathological findings:
- no effects observed
- Histopathological findings: non-neoplastic:
- no effects observed
- Histopathological findings: neoplastic:
- not specified
- Details on results:
- CLINICAL SIGNS AND MORTALITY
All rats survived to the end of the study. No clinical findings related to molybdenum trioxide exposure were observed.
BODY WEIGHT AND WEIGHT GAIN
The final mean body weights of exposed rats were similar to those of the control groups.
HAEMATOLOGY
There were no significant differences between control and exposed rats in hematology parameters.
CLINICAL CHEMISTRY
There were no significant differences between control and exposed rats in clinical chemistry parameters.
ORGAN WEIGHTS
There were no significant differences between control and exposed rats in absolute or relative organ weights.
GROSS PATHOLOGY
No chemcial-related lesions were observed.
HISTOPATHOLOGY: NON-NEOPLASTIC
No chemcial-related lesions were observed.
OTHER FINDINGS
There were no significant differences between control and exposed rats in sperm counts or motility, or liver copper concentrations.
Effect levels
- Dose descriptor:
- NOAEC
- Remarks:
- for chemical related clinical findings or lesions
- Effect level:
- > 100 mg/m³ air (nominal)
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- other: see 'Remark'
Target system / organ toxicity
- Critical effects observed:
- not specified
Applicant's summary and conclusion
- Conclusions:
- No treatment-related effects on mortality, clinical signs, final mean body weights, organ weights, hematology or clinical chemistry parameters, sperm count or motility and liver copper concentrations were observed. no treatment-related gross or microscopic lesions wer observed. The concentration of 100 mg/m^3 represents a NOAEC in this 13-week inhalation study on rats because no adverse effects were seen up to and including the highest concentration tested.
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