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Administrative data

Description of key information

The acute dermal and oral toxicity of the test substance ZMBT is very low, indicated by LD50 values greater than 5000 mg/kg. The acute oral LD50 value in rats is 7500 mg/kg bw mg/kg (Monsanto Co. 1975) and the dermal LD50 value in rabbits is greater than 7940 mg/kg bw (Monsanto Co. 1975). 

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
LD50
Value:
7 500 mg/kg bw

Acute toxicity: via dermal route

Endpoint conclusion
Dose descriptor:
LD50
Value:
7 940 mg/kg bw

Additional information

Acute toxicity: oral

The acute oral toxicity of ZMBT was evaluated in acute oral toxicity studies in rats. Although the study results are reliable the test design of the studies does not comply with the current guidelines.

In an acceptable documented study with Sprague-Dawley Albino rats a 20% solution-suspension of the test substance in corn oil was administered by gavage to male and female rats at doses of 5000, 6310, 7940 and 10000 mg/kg bw. A 14-day observation period followed administration. The oral LD50 calculated was 7500 mg/kg bw. Mortality occurred (one to two days after application) in the mid and higher dose groups evaluated (0/5, 1/5, 3/5, 5/5 at 5000, 6310, 7940 10000mg/kg bw, respectively). Clinical signs were observed and included reduced appetite and activity (one to three days in survivors), increasing weakness, collapse and death. Autopsy of decedent showed hemorrhagic areas of the lungs, liver hyperemia, and gastrointestinal inflammation; viscera of surviving animals appeared normal at sacrifice (Monsanto Co. 1975).

In a limited acute toxicity study with rats, a LD50 value greater 10000 mg/kg bw is suggested (TNO 1975). Male and female rats (10 per sex) were administered once by gavage with the test substance, which was suspended in propylene glycol (33 % w/v). After the treatment the rats were observed for signs of intoxication for 14 days. Autopsy was carried out at study termination. Two males and two females died 2 to 15 hours after treatment. Clinical signs occurred within a few minutes after treatment. All treated animals showed sluggishness followed by loss of consciousness (dosing volume 30ml/kg). After 24 hours the survivors recovered and looked quite healthy at study termination.

Acute toxicity: dermal

The acute dermal toxicity of ZMBT was evaluated in a limited but acceptable documented acute dermal toxicity study with New Zealand Albino rabbits (Monsanto Co. 1975). One male and one female rabbit were treated with 7940 mg/kg ZMBT (40% test substance solution-suspension in corn oil) for 24 hours. No mortality occurred during the study. Clinical signs observed included reduced appetite and activity (two to four days). Gross autopsy at study termination revealed no abnormalities in viscera in the treated animals. A dermal LD50 value greater than 7940 mg/kg bw is suggested.

Justification for classification or non-classification

No classification is required according to the classification criteria 67/548/EWG and regulation no. 1272/2008 (GHS).