Registration Dossier

Administrative data

Description of key information

The acute toxicity of kieselguhr soda ash flux calcined was tested via the oral and dermal route. The dermal toxicity was not considered relevant. Acute oral toxicity study in rats (OECD TG 420) LD50 >2000 mg/kg.  Acute inhalation toxicity study in rats (OECD TG 403) LD50 >2.6 mg/L maximum attainable dose concentration. 

Key value for chemical safety assessment

Additional information

Acute oral:

In the key study (Bradshaw 2010) oral toxicity was assessed using the fixed dose procedure. Following a sighting test at dose levels of 300 mg/kg and 2000 mg/kg, a further group of four fasted females was given a single oral dose of test material, as a suspension in arachis oil BP, at a dose level of 2000 mg/kg bodyweight. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy. The acute oral median lethal dose (LD50) of the test material in the female Wistar strain rat was estimated to be greater than 2000mg/kg bodyweight.

Acute dermal:

No acute dermal toxicity studies have been performed.The physiological properties of the substance do not suggest a significant rate of absorption through the skin and no systemic effects or other evidence of absorption were seen in the skin or eye irritation studies. Furthermore the test substance is essentially insoluble in water and therefore a limited amount of potential substance is available for absorption via the dermal route

Acute inhalation:

In the key study (Schuler 2010) a group of five male and five female albino rats was exposed by nose only, flow-past inhalation for four hours to the test item at a chemically determined mean concentration of 2.6 mg/L. All animals were observed for clinical signs and mortality and 14 days post exposure. The LC50 of soda-ash flux-calcined kieselguhr obtained in this study was estimated to be greater than 2.6 mg/L air (chemically determined mean aerosol concentration). This was the highest technically achievable concentration.

Justification for classification or non-classification

Acute toxicity: oral: The acute oral median dose (LD50) of kieselguhr soda ash flux calcined is greater than 2000 mg/kg bw and it is therefore not classified according to CLP Regulation (EC) No 1272/2008.

Acute toxicity: inhalation:The acute inhalation median concentration (LC50) of kieselguhr soda ash flux calcined was estimated to be greater than 2.7 mg/L. The result was achieved at the maximum attainable concentration and is considered to be equivalent to a limit test conducted at 5 mg/L and therefore kieselguhr soda ash flux calcined is not considered to be classified according to CLP Regulation (EC) No 1272/2008.