Registration Dossier

Administrative data

Description of key information

The oral LD50 value of Silicic acid(H2Si2O5), barium salt(1:1), lead-doped in Wistar rats was established to be within the range of 300-2000 mg/kg body weight. The dermal LD50 value of Silicic acid(H2Si2O5), barium salt(1:1), lead-doped in Wistar rats was established to exceed 2000 mg/kg body weight.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
LD50
300 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Acute toxicity: via dermal route

Endpoint conclusion
Dose descriptor:
LD50
5 000 mg/kg bw

Additional information

The oral LD50 value of Silicic acid(H2Si2O5), barium salt(1:1), lead-doped in Wistar rats was established to be within the range of 300-2000 mg/kg body weight in a study conform OECD 423, EC B.1 and EPA and JMAFF guidelines. Three females, treated at 2000 mg/kg, were sacrificed in moribund condition on Days 1 and 2. No further mortality occurred at the dose level of 300 mg/kg. Clinical signs observed during the study period were as follows: At 2000 mg/kg lethargy, tremor, flat and/or hunched posture, uncoordinated movements, abnormal gait, slow or quick breathing, piloerection, watery discharge from the eyes, pale appearance and/or ptosis were noted up to the day of death. At 300 mg/kg hunched posture and/or piloerection between Days 1 and 3. The body weight gain shown by the surviving animals over the study period was considered to be similar to that expected of normal untreated animals of the same age and strain. In one animal treated at 2000 mg/kg many reddish foci in glandular mucosa and black-brown content of the small intestine were observed. The other animals at 2000 mg/kg showed no macroscopic abnormalities.

The dermal LD50 value of Silicic acid(H2Si2O5), barium salt(1:1), lead-doped in Wistar rats was established to exceed 2000 mg/kg body weight (24 -hr occlusive exposure) in a study conform OECD 403, EC B.3 and EPA and JMAFF guidelines. No mortality was

observed. Flat/hunched posture and ptosis were noted among a few animals between Days 1 and 2. Scales on the treated skin or right flank and chromodacryorrhoea were incidentally noted among most animals during the observation period. The body weight gain shown by the surviving animals over the study period was considered to be similar to that expected of normal untreated animals of the same age and strain. No abnormalities were found at macroscopic post mortem examination of the animals. No acute inhalation toxicity study is available as already studies with two routes of exposure are available.

Justification for classification or non-classification

Based on the available data, Silicic acid(H2Si2O5), barium salt(1:1), lead-doped does not have to be classified for acute dermal toxicity according to Directive 67/548/EC or the CLP Regulation. For acute oral toxicity, the substance should be classified with Xn, R22 according to 67/548/EC or with Acute Cat. 4, H302 according to the CLP Regulation. For acute inhalation toxicity no data are available, but classification is based on the current Annex listing, see chapter on classification.