(Z)-pent-2-enenitrile

Endpoint summary

Description of key information

Oral: LD50: 198 mg/kg bw for male rats (kr 2, similar to OECD 401)
Dermal: LD50: < 800 mg/kg bw for male rats (kr 2, similar to OECD 402)
Inhalation: LC50: 2.82 mg/L for rats (kr 1, EPA OTS 798.1150)

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

198 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Dose descriptor:

LC50

Value:

2 820 mg/m³ air

Additional information

Acute toxicity: oral

A study was identified as the key study (Rondot, 1981). Cis-2-Pentenenitrile was tested for acute oral toxicity similarly to OECD test guideline No. 401. Groups of Sprague-Dawley rats (5/sex/group) were administered by gavage a single dose of Cis-Pentene-2 Nitrile commercial in aqueous suspension of 10% arabic gum at doses of  0, 200, 300 or 400 mg/kg bw and observed for 14 days (up to 45 days in the high dose group). Clinical signs include an increased spontaneous activity, with a lack of coordination in the movements. Males were more sensitive than females. Oral LD₅₀ Males = 198 mg/kg bw, oral LD₅₀ Females = 517 mg/kg bw and oral LD₅₀Combined = 304 mg/kg bw (236-392 mg/kg bw).

 

Acute toxicity: dermal

A study was identified as the key study (Rondot, 1981). Cis-2-Pentenenitrile was tested for acute dermal toxicity similarly to the OECD test guideline No. 402. Groups of Sprague-Dawley rats (5/sex/group) were exposed to Cis-Pentene-2 Nitrile commercial undiluted for 24 hours at doses of 0, 800, 1000 and 1200 mg/kg bw and observed for 14 days. A preliminary study was conducted. In this study, 3 groups (2M + 2F) were exposed to 100, 500 and 1000 mg/kg of 2-pentene nitrile and observed for 14 days. At 100 mg/kg, no mortality was observed. At 500 mg/kg, 2/2 males and 0/2 females died. At 1000 mg/kg, 2/2 males and 1/2 females died.

In the main study, clinical signs include a reduced spontaneous activity and trembling. Males were more sensitive than females. The DL50 identified in the main study are the following : Dermal LD₅₀ Males < 800 mg/kg bw, dermal LD₅₀ Females = 1039 mg/kg bw and

Dermal LD₅₀Combined = 833 mg/kg bw (671-1034 mg/kg bw)

Acute toxicity: inhalation

A study was identified as the key study (Panepinto, 1991). Cis-2-Pentenenitrile (98.6 % pure) was tested for acute inhalation toxicity in rats according to OECD 403 guideline in compliance with GLP. The assay was conducted on groups of Crl:CD®BR rats (5/sex) exposed nose only to vapors of cis-2-Pentenenitrile for 4 hours at concentrations of 0.06, 0.46, 2.16, 2.99 or 3.98 mg/L. Animals were then observed for 14 or 28 days due to the persistence of clinical signs. Mortality occurred at 2.99 and 3.98 mg/L. The clinical observations made during the recovery period in rats exposed at a level of 0.46 mg/L or greater were indicative of central nervous system effects. These observations included abnormal gait and mobility, hyperreactivity, hypersensitivity, muscle fasciculations, tremors and chattering of the teeth. There were no sex-related difference in the response of rats in this study based on lethality. Inhalation LC₅₀Combined = 2.82 mg/L (2.45 -3.22 mg/L). 

Justification for classification or non-classification

Based on the Male LD₅₀ of 198 mg/kg bw, Cis-2-Pentenenitrile is classified for acute oral toxicity as:

- Category 3 (H301 Toxic if swallowed) according to the CLP Regulation (1272/2008) as LD₅₀was found to be between 50 and 300 mg/kg bw.

- Toxic if swallowed (T; R25) according to the Directive 67/548/EC as LD₅₀ was found to be between 25 and 200 mg/kg bw.

Based on the Male LD₅₀ lower than 800 mg/kg bw (lowest dose tested) and on the fact that all male rats died at 500 mg/kg bw in the preliminary study, Cis-2-Pentenenitrile is classified for acute dermal toxicity in a conservative way as:

- Category 3 (H311 Toxic in contact with skin) according to the CLP Regulation (1272/2008).

- Toxic in contact with skin (T; R24) according to the Directive 67/548/EC.

Based on the Combined LC₅₀ of 2.82 mg/L/4h, Cis-2-Pentenenitrile is classified for acute inhalation toxicity as:

- Category 3 (H331 Toxic if inhaled) according to the CLP Regulation (1272/2008) as LC₅₀was found to be between 2 and 10 mg/L/4h (vapours).

- Harmul by inhalation (Xn; R20) according to the Directive 67/548/EC as LC₅₀ was found to be between 2 and 20 mg/L/4h (vapours).