Silicic acid (H4SiO4), zirconium(4+) salt (1:1), reaction products with sodium hydroxide

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

other: Expert assessment

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Expert assessment as opposed to experimental result

Data source

Reference

Reference Type:

other: Expert Assessment

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Principles of method if other than guideline:

Assessment

GLP compliance:

no

Test type:

other: Assessment

Test material

Test material information

Constituent 1

Reference substance name:

Silicic acid (H4SiO4), zirconium(4+) salt (1:1), reaction products with sodium hydroxide

EC Number:

304-802-4

EC Name:

Silicic acid (H4SiO4), zirconium(4+) salt (1:1), reaction products with sodium hydroxide

Cas Number:

94279-56-8

Molecular formula:

Silicic acid (H4SiO4), zirconium(4+) salt (1:1), reaction products with sodium hydroxide

IUPAC Name:

Silicic acid (H4SiO4), zirconium(4+) salt (1:1), reaction products with sodium hydroxide

Results and discussion

Effect levels

Remarks on result:

other: The substance in water has a pH of >13. Consequently, it could not be tested as is; it would he theoretically possible to test the material after neutralisation, however, the test substance in this scenario would cease to be the original substance.

Any other information on results incl. tables

Assessment

Applicant's summary and conclusion

Interpretation of results:

other: Assessment

Executive summary:

This substance is the product of a reaction between Zircon (EC no 239-019-6) and sodium hydroxide. The substance in water has a pH of >13. Consequently, it could not be tested as is; it would he theoretically possible to test the material after neutralisation, however, the test substance in this scenario would cease to be the original substance. It would thus be more appropriate to assess the toxicity based on the toxicity of the sodium silicate part of the molecule and assess the systemic toxicity by reading across from other water-soluble zirconium salts. Zirconium acetate has been shown to have a dermal toxicity of >5000 mg/kg; in addition, toxicity of Silicic acid (H₄SiO₄), zirconium(4+) salt (1:1), reaction products with sodium hydroxide by the oral route has been assessed. An LD₅₀ of approximately 1300 mg/kg has been established. This further supports the assertion of low systemic toxicity.  In addition, a dermal toxicity study has been conducted for silicic acid, potassium salt (215-199-1), which showed an LD₅₀ of >5000 mg/kg. Running an acute dermal study would add nothing to the hazard assessment for this substance, and risk management measures are driven primarily by its corrosive nature due to the high pH. Determination of acute toxicity by the dermal route is therefore considered unnecessary.

The above should be considered as an expert statement to waive the requirement for testing for acute toxicity by the dermal route under REACH Annex VIII for endpoint 8.5.3.