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Description of key information

Acute toxicity of bentonite acid leached has been tested via the oral, inhalation and dermal route. Acute oral toxicity study in rats LD50 > 5000 mg/kg, Acute inhalation toxicity study in rats LC50 > 50 mg/L and acute dermal toxicity in rats (OECD TG ) LD50 > 2000 mg/kg. Bentonite acid leached is not considered to be harmful by either route and is not classified for acute toxicity. 

Key value for chemical safety assessment

Additional information

Acute toxicity: Oral route

In a key study (Nitka 1985) 5 male and 5 female rats each recieved a single oral dose of bentonite acid leached at a dose level of 5000 mg/kg bw. Animals were observed for clinical signs and mortality 1, 3, 6 and 24 hours after treatment and daily thereafter for a total of 14 days. After 14 days animals were subjected to gross necropsy. No mortalities were observed and the LD50 was determined to be > 5000 mg/kg bw.

Acute toxicity: Inhalation route

In a key study (Nitka 1988) 5 male and 5 female rats were exposed to bentonite acid leached for 1 hour at an atmospheric concentration of 200 mg/L. Animals were observed for clinical signs and mortality 1,3, and 24 hours after treatment and daily thereafter for a total of 14 days. After 14 days animals were subjected to gross necropsy. No mortalities were observed and the LD50 was determined to be > 200 mg/L.

The classification criteria for acute inhalation toxicity relate to a 4 hour experimental exposure period. Where LC50 values have been obtained in studies using exposure durations shorter or longer than 4 hours these may be adjusted to a 4 hour equivalent using Habers law (Cn.t = k), where 'C' is the concentration, 'n' is a regression coefficient, t is the exposure time and 'k' is a constant. For extrapolation to longer duration it is recommended to set n = 1. Using Habers law the LC50 for the inhalation study is 50 mg/L.

Acute toxicity: Dermal route

In a key study (Bradshaw 2010) 5 male and 5 female rats were given a single 24 h, semi-occluded dermal application of the test material to intact skin at a dose level of 2000 mg/kg bw. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy. There were no deaths or signs of systemic toxicity or dermal irritation. The acute dermal LD50 was found to be greater than 2000 mg/kg bw.

Justification for classification or non-classification

Acute toxicity oral: The acute oral toxicity (LD50) of bentonite acid leached is > 2000 mg/kg and it is therefore not classified according to CLP Regulation (EC) No 1272/2008.

Acute toxicity inhalation: The acute inhalation toxicity (LC50) of bentonite acid leached is > 50 mg/L and is therefore not classified according to CLP Regulation (EC) No 1272/2008.

Acute toxicity dermal: The acute dermal toxicity (LD50) of bentonite acid leached is >2000 mg/kg and it is therefore not classified according to CLP Regulation (EC) No 1272/2008

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