Silicon

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions. Four different reports included! Read-across to synthetic amorphous silica.

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1978

Report date:

1978

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

1978

Report date:

1978

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Four animals per group used, two each treated on the intact and abraded skin: The substance was mixed with distilled water to form an aqueous paste

GLP compliance:

no

Test type:

standard acute method

Test material

Test material information

Constituent 1

Reference substance name:

Silicon dioxide

EC Number:

231-545-4

EC Name:

Silicon dioxide

Cas Number:

7631-86-9

IUPAC Name:

dioxosilane

Details on test material:

ZEO 49, ZEOSYL 113, ZEOSYL 200, and ZEOFREE 153 (not further specified): CAS-Name: Silica, precipitated, cryst.-free; CAS-No.: 112926-00-8

Test animals

Species:

rabbit

Strain:

New Zealand White

Sex:

not specified

Administration / exposure

Type of coverage:

occlusive

Vehicle:

water

Details on dermal exposure:

Four animals per group used, two each treated on the intact and abraded skin: The substance was mixed with distilled water to form an aqueous paste

Duration of exposure:

24 h

Doses:

2000, 3000, 4000, and 5000 mg/kg

No. of animals per sex per dose:

4 per dose group

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight, organ weights

Results and discussion

Effect levels

Sex:

not specified

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Any other information on results incl. tables

Local effect: very slight erythema (score 1 of 4), reversible after 2 days (ZEO 49), after 4 d (ZEOSYL) or 5 d (ZEOFREE) in one or a few animals. No systemic signs of toxicity or organ toxicity.
 

Applicant's summary and conclusion

Interpretation of results:

other: non-toxic

Executive summary:

In 1978, Woltjen and Calkins presented their study results on the acute dermal toxicity of precipitated synthetic silicas in four different reports. After acute dermal application of up to 5,000 mg/kg bw of aqueous pastes of precipitated synthetic amorphous silica to the intact and abraded skin of rabbits for 24 hours under occlusive conditions, no signs of systemic or organ toxicity were noted. There were only very slight transient erythemas at the site of treatment in solitary animals. In conclusion, the dermal exposure to high doses of synthetic amorphous silica will produce no systemic toxicity and the LD₅₀ is >5,000 mg/kg.