ethynyl cyclopropane

Endpoint summary

Description of key information

Acute Oral toxicity
Rat: 	LD50 (m/f) > 2000 mg/kg bw (EU Method B.1 bis (Acute Oral Toxicity - Fixed Dose Procedure); DuPont Merck, 1997)
    	
Acute Inhalation toxicity
Rat:	LC50 (m/f) > 22.3 mg/l (OECD 403; DuPont Merck, 1997)
Acute Dermal toxicity
Rat:	LD50 (m/f) > 2000 mg/kg bw (EU method B.3 Acute Toxicity (Dermal); DuPont Merck, 1997)

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Dose descriptor:

LC50

Value:

22.3 mg/m³ air

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Additional information

Acute Oral toxicity

The acute oral toxicity of the test substance was investigated in two groups of 5 male and 5 female rats, given doses of 500 and 2000 mg/kg bw as gavage. Signs of toxicity included piloerection, respiratory distress, hunched posture, waddling/unsteady gait and walking on toes all commonly seen in both males and females. Less often seen were; lethargy, pallid extremities, body tremors, thin appearance (both sexes) and blue/cold extremities, nasal discharge (red), soft to liquid feces, prostration, protruding eyes and ungroomed appearance (females only). One male and two females treated at 2000 mg/kg died during the study. Deaths occurred between three and a half hours and four days post dose.

 

Acute Inhalation toxicity

The acute inhalation toxicity of Ethynyl cyclopropane was assessed by exposing three groups of rats, each for a period of 4 hours, to a vapour produced from the test substance. During exposure, clinical signs of toxicity seen in rats exposed to Ethynyl cyclopropane at 22.3 mg/l included unsteady movement, occasional involuntary muscular contractions, unresponsiveness, piloerection, partial closing of the eyes and shallow respiration. Clinical signs seen in rats exposed to Ethynyl cyclopropane at 3.22 mg/l were partial closing of the eyes and a reduced

response to stimuli. There were no clinical signs during exposure to Ethynyl cyclopropane at 0.50 mg/l. Involuntary muscular contractions, staggering and hyperactivity were seen for up to 40 minutes post-exposure in rats exposed to Ethynyl cyclopropane at 22.3 mg/l. All rats exposed at this level were normal in appearance and behaviour within 40 minutes post-exposure. There were no clinical signs observed during the observation period in rats exposed to Ethynyl cyclopropane at 3.22 or 0.50 mg/l.

 

Acute Dermal toxicity

The acute dermal toxicity of the test substance was investigated in 5 male and 5 female rats. The test material was applied unchanged to the clipped epidermis of each animal at a limit dose level of 2000 mg/kg bw under semiocclusive conditions for 24 hours. No deaths and no systemic signs of systemic toxicity were noted for the limit dose. Reaction to treatment was confined to a localized (transient) dermal reaction at the treatment site involving very slight irritation (Grade 1 erythema with or without Grade 1 oedema). This response was first notable in eight animals following removal of the dressings, evident in smaller number of animals over the following days and resolving in all instances within five days of treatment. Bodyweight changes in the majority of animals were considered acceptable throughout for a study of this nature and duration. No abnormalities were observed at the study termination necropsy.

Justification for classification or non-classification

Acute Oral toxicity

Based on the criteria defined by the EU system, the test substance needs not to be labelled for acute oral toxicity, according to the criteria defined by the GHS system the test substance is classified to GHS Cat 5 because deaths occurred in the highest dosing group of 2000 mg/kg bw in male and female animals that could be attributed to the test substance administration.

Acute Inhalation toxicity

Based on the criteria defined by the EU and the GHS system, the test substance needs not to be labelled for acute inhalation toxicity, because no death occurred in the highest dosing group of 22.3 mg/l air in male and female animals that could be attributed to the test substance administration.

Acute Dermal toxicity

Based on the criteria defined by the EU and the GHS system, the test substance needs not to be labelled for acute dermal toxicity, because no death occurred in the highest dosing group of 2000 mg/kg bw in male and female animals that could be attributed to the test substance administration.