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Toxicological information

Acute Toxicity: inhalation

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Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study included in EU risk assessment for zinc metal as a key study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1996

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes

Test material

Constituent 1
Reference substance name:
Zinc
EC Number:
231-175-3
EC Name:
Zinc
Cas Number:
7440-66-6
IUPAC Name:
zinc
Details on test material:
- Name of test material (as cited in study report): fine zinc powder, labelled as “Zincstaub superfein 620”

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female

Administration / exposure

Route of administration:
inhalation: dust
Type of inhalation exposure:
nose only
Vehicle:
other: no data
Details on inhalation exposure:
Of the particles, 85% had an aerodynamic diameter ≤8.2 μm and 27% ≤5 μm. The mass median aerodynamic diameter was determined to be 6.2 μm with a geometric standard deviation of 1.7.
Analytical verification of test atmosphere concentrations:
not specified
Duration of exposure:
ca. 4 h
Concentrations:
> 5.41 g Zn/m3 air (the highest attainable concentration)
No. of animals per sex per dose:
according to guideline study
Control animals:
yes
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: as per guideline
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight,organ weights, histopathology, other: yes
Statistics:
as per guideline

Results and discussion

Preliminary study:
no information
Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 5 410 mg/m³ air
Mortality:
No mortalities occurred during the 14-day observation period.
Clinical signs:
other: visually decreased breathing rate (first 2 days) and sluggishness in all animals (only shortly after exposure) and blepharospasm in two male and two female rats (first day).
Body weight:
no information
Gross pathology:
Abnormalities at necropsy consisted of lung changes (white spots on three or all five lung lobes) in two males and four females
Other findings:
none

Any other information on results incl. tables

none

Applicant's summary and conclusion

Interpretation of results:
practically nontoxic
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
LC50 greater than 5.41 g Zn/m3
Executive summary:

An LC50-value of > 5.41 g Zn/m3air (the highest attainable concentration for the same very fine zinc powder, labelled as “Zincstaub superfein 620”) for a single 4-hour exposure period was found in a nose only exposure study in Wistar rats carried out according to OECD guideline no. 403. Of the particles, 85% had an aerodynamic diameter ≤8.2 μm and 27% ≤5 μm. The mass median aerodynamic diameter was determined to be 6.2 μm with a geometric standard deviation of 1.7. Clinical signs after exposure consisted of visually decreased breathing rate (first 2 days) and sluggishness in all animals (only shortly after exposure) and blepharospasm in two male and two female rats (first day). No mortalities occurred during the 14-day observation period. Abnormalities at necropsy consisted of lung changes (white spots on three or all five lung lobes) in two males and four females.

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