Registration Dossier
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EC number: 215-222-5 | CAS number: 1314-13-2
- 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
Acute oral toxicity: key studies carried out according to OECD guideline no 401 or 423 indicating for both micro- and nanomaterial zinc oxide LD50 > 2000 mg/kg bw
Acute inhalation toxicity: key study carried out according to OECD guideline no 403 indicating for micro zinc oxide LC50 > 5.7 mg/L/4hrs.
Acute dermal toxicity: key study carried out according to OECD guideline no 402 indicating for nano zinc oxide LD50 >2000 mg/kg bw.
Key value for chemical safety assessment
Acute toxicity: via oral route
Link to relevant study records
- Endpoint:
- acute toxicity: oral
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Used in EU risk assessment for zinc oxide, limited study details provided
- Qualifier:
- equivalent or similar to
- Guideline:
- OECD Guideline 401 (Acute Oral Toxicity)
- GLP compliance:
- not specified
- Test type:
- standard acute method
- Limit test:
- yes
- Species:
- rat
- Strain:
- Wistar
- Sex:
- male/female
- Details on test animals and environmental conditions:
- 5 per sex
- Route of administration:
- oral: gavage
- Vehicle:
- water
- Details on oral exposure:
- single dose by oral gavage in water and observed for 14 days
- Doses:
- single dose of 5 gZnO/kg bw
- No. of animals per sex per dose:
- 5 per sex
- Control animals:
- not specified
- Details on study design:
- no further information
- Statistics:
- no data
- Preliminary study:
- no further information
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- > 5 000 mg/kg bw
- Mortality:
- no mortality
- Clinical signs:
- no adverse signs of toxicity
- Body weight:
- no adverse signs of toxicity
- Gross pathology:
- no adverse signs of toxicity
- Interpretation of results:
- practically nontoxic
- Remarks:
- Migrated information Criteria used for interpretation of results: EU
- Conclusions:
- LD50 > 5000 mg ZnO/kg bw was determined.
- Executive summary:
In an acute toxicity test Wistar rats (5/sex) were given a single dose of 5 g ZnO/kg bw (in water) by gavage and observed for 14 days. No mortality and signs of toxicity were observed. The LD50for rats is therefore >5 g ZnO/kg bw.
Reference
none
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
- Dose descriptor:
- LD50
- Value:
- 5 000 mg/kg bw
Acute toxicity: via inhalation route
Link to relevant study records
- Endpoint:
- acute toxicity: inhalation
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Used in EU risk assessment for zinc oxide, guideline study, reliable with restrictions
- Qualifier:
- equivalent or similar to
- Guideline:
- OECD Guideline 403 (Acute Inhalation Toxicity)
- GLP compliance:
- not specified
- Test type:
- standard acute method
- Limit test:
- yes
- Species:
- rat
- Strain:
- not specified
- Sex:
- male/female
- Details on test animals and environmental conditions:
- no information available
- Route of administration:
- inhalation
- Type of inhalation exposure:
- nose/head only
- Vehicle:
- other: no data
- Analytical verification of test atmosphere concentrations:
- not specified
- Duration of exposure:
- ca. 4 h
- Concentrations:
- Aerosol concentration was 5.7 mg/l
- No. of animals per sex per dose:
- 10 per sex
- Control animals:
- yes
- Details on study design:
- 10 male and 10 female animals per group were exposed to zinc oxide aerosol (head and nose only) for 4 h. Aerosol concentration was 5.7 mg/l and the particle size distribution had a mass median aerodynamic diameter of 4 µm ± 2.9 (GSD). Only one concentration and a control group were tested. All animals survived up to day 14 post exposure.
- Statistics:
- no information
- Preliminary study:
- no information
- Sex:
- not specified
- Dose descriptor:
- LC50
- Effect level:
- > 5 700 mg/m³ air
- Exp. duration:
- 4 h
- Mortality:
- no mortality
- Clinical signs:
- other: only a dusty fur on the head, no adverse effects noted
- Body weight:
- no change in body weights observed
- Gross pathology:
- no adverse effects observed.
- Other findings:
- none observed
- Interpretation of results:
- practically nontoxic
- Remarks:
- Migrated information Criteria used for interpretation of results: EU
- Conclusions:
- LC50 4 hours >5.7 mg ZnO/l
- Executive summary:
In an acute inhalation toxicity study, 10 male and 10 female animals per group were exposed to zinc oxide aerosol (head and nose only) for 4 h. Aerosol concentration was 5.7 mg/l and the particle size distribution had a mass median aerodynamic diameter of 4mm ± 2.9 (GSD). Only one concentration and a control group were tested. All animals survived up to day 14 post exposure. Apart from a dusty fur on the head the day after the exposure, no effects were seen. Body weights developed normally. At pathological examination all organs were normal. The LC50was >5.7 mg/l.
Reference
no information
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
- Dose descriptor:
- LC50
- Value:
- 5 700 mg/m³
Acute toxicity: via dermal route
Link to relevant study records
- Endpoint:
- acute toxicity: dermal
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- other: The study is conducted accordign to the OECD Guideline in compliance with GLP.
- Qualifier:
- according to
- Guideline:
- OECD Guideline 402 (Acute Dermal Toxicity)
- Deviations:
- no
- GLP compliance:
- yes (incl. certificate)
- Test type:
- standard acute method
- Limit test:
- yes
- Species:
- rat
- Strain:
- Wistar
- Sex:
- male/female
- Details on test animals and environmental conditions:
- TEST ANIMALS
- Source: Charles River, Sulzefeld, Germany
- Age at study initiation: 10 - 11 weeks
- Weight at study initiation: males (mean): 308.92 g, females (mean): 193.28 g
- Housing: 2 rats of same sex per cage, wooden absorbing bedding
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 4 weeks
ENVIRONMENTAL CONDITIONS
- Temperature: 22 +/- 2°C
- Humidity: 55 +/- 15%
- Air changes (per hr): fully airconditioning
- Photoperiod (hrs dark / hrs light): 12 h / 12 h - Type of coverage:
- semiocclusive
- Vehicle:
- corn oil
- Details on dermal exposure:
- TEST SITE
- Area of exposure: back
REMOVAL OF TEST SUBSTANCE
- Washing (if done): water
- Time after start of exposure: 24 h
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2000mg/kg bw
- Concentration (if solution): 0.5mg test item in 400µl corn oil
- Constant volume or concentration used: no
- For solids, paste formed: yes - Duration of exposure:
- 24 h
- Doses:
- 2000 mg/kg bw
- No. of animals per sex per dose:
- 5/sex
- Control animals:
- other: untreated skin of same animal
- Details on study design:
- - Duration of observation period following administration: 14 d
- Frequency of observations and weighing: Twice a day, once on weekends
- Necropsy of survivors performed: Yes
- Other examinations performed: Clinical signs, body weight, gross pathology - Statistics:
- Means and standard deviation were calculated using standard statistical tests.
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- > 2 000 mg/kg bw
- Based on:
- test mat.
- Remarks on result:
- other: No mortality occured
- Mortality:
- Not observed
- Clinical signs:
- Slight signs of general discomfort as often seen in dermal toxicity studies, the general health status was good throughout the study
- Body weight:
- Treatment related effects were not observed
- Gross pathology:
- No abnormalties detected
- Interpretation of results:
- not classified
- Remarks:
- Migrated information Criteria used for interpretation of results: EU
- Conclusions:
- Under the test conditions, the LD50 of nanoscaled ZnO is estimated to be > 2000mg/kg bw.
- Executive summary:
The study was conducted to determine the acute dermal toxicity of nanoscaled ZnO according to the OECD Guideline 402 in compliance with GLP.
2000 mg/kg bw of the test substance were semiocclusively administered for 24 h as pasty formulation in corn oil to the shaved and defaffed back of 5 female and 5 male rats. After the end of the exposure period, the test substance paste was recovered as effectively as possible using water and the animals were observed for 14 d. During the present study no mortality occurred and there were no indications of systemic toxicity, no effects regarding the body weight and neither clinical signs nor pathological findings observed.
The LD50 of the test substance is therefore estimated to be > 2000 mg/kg bw.
Reference
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
- Dose descriptor:
- LD50
- Value:
- 2 000 mg/kg bw
Additional information
- With LD50values consistently exceeding 2,000 mg/kg bw, zinc oxide (LD50ranges between 5,000 and 15,000mg/kg bw), shows very low level of acute oral toxicity.
- With LC50 value > 5.7 mg/L/4hrs, zinc oxide is shown to be of low acute inhalation toxicity.
- There are no available data on which to evaluate acute dermal toxicity for ZnO micromaterial. However, acute dermal toxicity can be considered to be low in view of the poor absorption by this route.
Zinc oxide nanomaterial:
Tests performed specifically on nano-ZnO demonstrate alsovery low acute oral toxicity (i.e. LD50 values consistently exceeding 2,000 mg/kg bw). The only available inhalation data on nano-ZnO indicates an LC50 value of > 1.79 mg/L. However, only this one single dose of 1.79 mg/L was tested which wasthe maximum attainable exposure concentration for achieving respirable particle size.Data on nano-ZnO confirms low acute dermal toxicity with LD50>2000 mg/kg bw.
In conclusion, for nano-ZnO no nano-specific acute toxicity could be identified. Zn2+ion determines the toxicity of ZnO and read across between various forms of ZnO (micro-scale, nano, coated or not) is fully supported.
Of significance for humans from an acute toxicity standpoint is the occurrence of metal fume fever following exposure to ultrafine particles of special grades of zinc oxide in context of very specific operations such as cutting or welding of galvanised steel. Metal fume fever is exclusively associated with freshly formed ultrafine particulate zinc oxide (<0.1 µm). As these ultrafine particles (nanoparticles) rapidly agglomerate to bigger particles, which are normally encountered at production and processing sites, at these sites there is no indication for metal fume fever. According to the response from 11 zinc companies to a questionnaire, there have been no observations of zinc metal fume fever over the last decade and in recent occupational practice (EU RAR, 2004a-f). However in light of responsible care and since no studies are available that allow the establishment of a NOAEL for metal fume fever with a reasonable degree of certainty, a LOAEL (5 mg ZnO/m3) for 2 hours (showed the typical metal fume fever symptoms beginning 4 to 8 hours after exposure and disappearing within 24 hours) can be used for metal fume fever based on the study by Gordon et al.(1992).
Justification for classification or non-classification
Zinc oxide (micro- and nanomaterial) isof low acute, dermal and inhalation toxicity not requiring a classification for acute toxicity according to the EC criteria.
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