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Administrative data

Description of key information

Zinc sulphate is a severe eye irritant but not a skin irritant based on animal eye and skin irritation studies

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records
Reference
Endpoint:
eye irritation: in vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Not reported
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Used in risk assessment report for ZnSO4, acceptable for assessment
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study
Qualifier:
according to
Guideline:
OECD Guideline 405 (Acute Eye Irritation / Corrosion)
Deviations:
not specified
Qualifier:
according to
Guideline:
EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)
Deviations:
not specified
Principles of method if other than guideline:
Not applicable
GLP compliance:
not specified
Species:
rabbit
Strain:
New Zealand White
Details on test animals or tissues and environmental conditions:
No information
Vehicle:
unchanged (no vehicle)
Controls:
yes, concurrent no treatment
Amount / concentration applied:
Approximately 98.1 mg of the test material
Duration of treatment / exposure:
Single instillation, no eye wash
Observation period (in vivo):
At 1, 24, 48 and 72 hours, 7, 14 and 21 days after exposure.
Number of animals or in vitro replicates:
Three male animals
Details on study design:
No further details
Irritation parameter:
conjunctivae score
Remarks:
redness
Basis:
mean
Time point:
other: 24 h
Score:
ca. 2
Max. score:
3
Reversibility:
not specified
Irritation parameter:
conjunctivae score
Remarks:
redness
Basis:
mean
Time point:
other: 48 h
Score:
2.7
Max. score:
3
Reversibility:
not specified
Irritation parameter:
conjunctivae score
Remarks:
redness
Basis:
mean
Time point:
other: 72 h
Score:
ca. 2.7
Max. score:
3
Reversibility:
not specified
Irritation parameter:
chemosis score
Basis:
mean
Time point:
other: 24 h
Score:
ca. 2
Max. score:
4
Reversibility:
not specified
Irritation parameter:
chemosis score
Basis:
mean
Time point:
other: 48 h
Score:
ca. 2.7
Max. score:
4
Reversibility:
not specified
Irritation parameter:
chemosis score
Basis:
mean
Time point:
other: 72 h
Score:
ca. 3.7
Max. score:
4
Reversibility:
not specified
Irritant / corrosive response data:
Corneal injury was seen as slight dulling of the normal lustre (opacity grade 0) and/or epithelial damage (10% of the corneal area) in two animals. This injury had resolved within 24 hours in one animal and within 72 hours in the other animal.
Irritation of the conjuctivae was seen as redness (mean scores over 24-72 hours 2, 2.7 and 2.7), chemosis (mean scores 2, 2.7 and 3.7) and discharge.
Yellow/white spots were observed in the tissue of the lower eyelid, nictitating membrane and/or sclera in all animals from day 7 until termination. These spots were described as signs of necrosis and consisted of encapsulated material of unknown origin which caused protrusions at termination of the study.
Other effects:
Reduced elasticity of the eyelids was noted in one animal, 72 hours and 7 days after instillation.

None       

Interpretation of results:
highly irritating
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
Based on the degree and persistence of the corneal injury, zinc sulphate is considered to cause severe ocular irritation
Executive summary:

In a well-performed eye irritation/corrosion study, conducted according to Directive 92/69/EEC B.5 and OECD guideline 405, three male New Zealand White rabbits were treated by instillation of approximately 98.1 mg of zinc sulphate (ZnSO4.7H2O) into the conjuctival sac of one eye. The other eye remained untreated and served as control. The eyes (unrinsed) were examined at 1, 24, 48 and 72 hours and 7, 14 and 21 days after instillation.

No symptoms of systemic toxicity were observed and no mortality occurred.

Corneal injury was seen as slight dulling of the normal lustre (opacity grade 0) and/or epithelial damage (10% of the corneal area) in two animals. This injury had resolved within 24 hours in one animal and within 72 hours in the other animal.

Irritation of the conjuctivae was seen as redness (mean scores over 24-72 hours 2, 2.7 and 2.7), chemosis (mean scores 2, 2.7 and 3.7) and discharge.

Yellow/white spots were observed in the tissue of the lower eyelid, nictitating membrane and/or sclera in all animals from day 7 until termination. These spots were described as signs of necrosis and consisted of encapsulated material of unknown origin which caused protrusions at termination of the study. Reduced elasticity of the eyelids was noted in one animal, 72 hours and 7 days after instillation.

Based on the degree and persistence of the corneal injury, zinc sulphate is considered to cause severe ocular irritation.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

The soluble zinc compounds (i. e., zinc chloride, zinc sulphate and diammonium tertachlorozincate), displayed in vivo varying degrees of skin and eye irritation ranging from moderate to severely irritating.

Based on the available data of the soluble zinc compounds, soluble zinc chloride is classified as corrosive (C; R34) according to EC criteria due to severe skin irritancy seen in animals at concentrations of 1% solution and irreversible damage to eyes caused by zinc chloride after accidental exposure in humans. Zinc chloride has also shown signs of respiratory tract irritation in single exposure studies (see acute inhalation toxicity).

On the other hand zinc sulphate was not irritating to skin but is a severe eye irritant and has been classified as a severe eye irritant (Xi R41) according to EC criteria.

In vitro data shows that zinc bis(dihydrogen phosphate) was not irritating to skin. While no in vivo data exists on zinc bis(dihydrogen phosphate), in vitro data suggests zinc bis(dihydrogen phosphate) is moderately irritating to eyes. Diammonium tetrachlorozincate appears to be a moderate eye irritant however no classification has been assigned. While no specific irritation data were identified for triammonium pentachlorozincate, it is (due to its similar solubility characteristics) likely to display a toxicity profile similar to that of the soluble diammonium tetrachlorozincate.



Effects on eye irritation: highly irritating

Justification for classification or non-classification

Zinc sulphate was not irritating to skin but is a severe eye irritant and has been classified as a severe eye irritant (Xi R41) or Eye Damage 1; H318 according to EC criteria.