Zinc

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

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

Test material information

Constituent 1

Reference substance name:

Zinc

EC Number:

231-175-3

EC Name:

Zinc

Cas Number:

7440-66-6

Molecular formula:

Zn

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:

GHS criteria not met

Conclusions:

LC50 greater than 5.41 g /m3

Executive summary:

An LC₅₀-value of > 5.41 g /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.