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EC number: 500-446-0 | CAS number: 160901-09-7 1 - 2.5 moles ethoxylated
Oral (OECD 401), rat: LD50 = 3488 mg/kg bw
Dermal (OECD 402), rabbit: LD50 = 2000 mg/kg bw
Inhalation (OECD 403), rat, 4 h, (limit test): LC50 > 1600mg/m³ (maximum technically attainable concentration)
To cover the endpoint acute toxicity of substance C9-11AE (CAS 68439-46-3), studies from similar substances were taken for a weight-of-evidence approach. Read-across is justified because the length of the alkyl chain does not exert any meaningful influence on acute toxicity, whereas the degree of ethoxylation is of more importance. Up to the level of EO = 4, which includes all read-across substances, the toxicity is low (HERA, 2009).
The first acute oral toxicity study with C6-10AE (CAS 112-59-4) was conducted equivalent to OECD Guideline 401. Five Wistar rats were dosed at 900, 1900, 3700, 7400, 15,000 mg/kg bw (males) and 1900, 3700, 7400 mg/kg bw (females), respectively. Mortalities occurred at a dose level of 3700 mg/kg bw and above resulting in a LD50 of 4600 mg/kg bw for males and 3488 mg/kg bw for females, respectively. Clinical signs comprised sluggishness, unsteady gait and a prostrated appearance at all doses. Moreover, necropsy revealed dark red or dark pink lungs in the deceased animals.
The second study addressing acute oral toxicity was conducted with C6-12AE (CAS 68439-45-2) according to OECD Guideline 401. For five males the study was conducted as a limit test with a single dose of 5050 mg/kg bw. The female Sprague-Dawley rats received 4000, 5050 and 5500 mg/kg bw, each dose level consisting of five animals. The LD50 value was determined to be 5130 mg/kg bw for females and greater than 5050 mg/kg bw for males, respectively. Abnormal necropsy findings occurred primarily in the deceased females and pertained to the lungs, liver, and contents of the gastrointestinal tract and bladder.
The final acute oral toxicity study with C10-16AE (CAS 68002-97-1) was as well conducted equivalent to OECD Guideline 401. In this limit test five Sprague-Dawley rats per sex received 5050 mg/kg bw. No mortalities occurred, hence, the LD50 value was set to greater than 5050 mg/kg bw.
For addressing acute dermal toxicity, the same read-across substances as for acute oral toxicity were taken. The first study with C6-10AE (CAS 112-59-4) equivalent to OECD Guideline 402 was carried out on five New Zealand White rabbits per sex and dose. Both sexes were dosed at 900, 1900 and 3700 mg/kg bw under occlusive conditions for 24 hours, with the females receiving an additional dose of 2600 mg/kg bw. Mortalities occurred at a dose level of 1900 mg/kg bw and above, resulting in a LD50 of 2000 mg/kg bw for males and 2216 mg/kg bw for females, respectively. Moreover, necropsy revealed dark red or dark pink lungs in the deceased animals.
The second study regarding acute dermal toxicity was conducted with C6-12AE (CAS 68439-45-2). This limit test was conducted equivalent to OECD Guideline 402, however, only four Wistar rats per sex were used. The dose level of 2000 mg/kg bw was applied occlusive for 24 hours and caused neither treatment-related clinical signs nor mortalities. Hence, the LD50 was determined to be greater than 2000 mg/kg bw.
The third acute dermal toxicity study with C10-16AE (CAS 68002-97-1) was as well a limit test conducted equivalent to OECD Guideline 402. In this limit test five New Zealand White rabbits per sex received 2000 mg/kg bw for a 24 h-occluded exposure. No mortalities occurred, hence, the LD50 value was set to greater then 2000 mg/kg bw.
There are two studies available addressing acute inhalation toxicity, being performed with C6-10AE (CAS 112-59-4) and C10-16AE (CAS 68002-97-1) and equivalent to OECD Guideline 403.
In the first study five Wistar rats per sex were exposed for a period of 6 hours to a vapour of the test substance at the calculated saturated vapour concentration of 100 mg/m³. No mortality or clinical signs occurred during the exposure period. The LC50 was determined to be greater than 100 mg/m³ for exposure to an aerosol of the test substance for 6 hours.
In the second study with C10-16AE (CAS 68002-97-1) five Sprague Dawley rats/sex were exposed for a period of 4 hours to an aerosol of the test substance at a concentration of 1600 mg/m³ (corresponding to 1.6 mg/L), which is the maximum technically attainable concentration of the test substance with a MMAD < 4 µm (limit test). No mortality occurred during the exposure or the 14-day observation period. The animals demonstrated clinical signs of toxicity like slight nasal discharge and lacrimation during exposure as well as slight, red nasal discharge post-exposure. The LC50 was determined to be greater than 1600 mg/m³ for exposure to an aerosol of the test substance for 4 hours.
Justification for selection of acute toxicity – oral endpoint
Study with the lowest definitive dose descriptor was selected.
Justification for selection of acute toxicity – inhalation endpoint
Study with the highest maximum achievable dose was selected.
According to the classification criteria of Directive 67/548/EEC and Regulation (EC) No 1272/2008 the substance does not need to be classified for acute toxicity.
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