Dimethylammonium 2,4-dichlorophenoxyacetate

Endpoint summary

Description of key information

The following information is taken into account for any hazard / risk assessment:
Oral Toxicity
Key, Kita, 1997, Aminopielik 720, rat, acute oral, RL1 – LD50 = 555 mg/kg bw (based on an active ingredient content of 72.6% and a LD50 of 764 mg/kg bw observed in the respective study)
Kita, 1991, Aminopielik 600, rat, acute oral, RL1 – LD50 = 685 mg/kg bw (based on an active ingredient content of 51.6% and a LD50 of 994 mg/kg bw observed in the respective study) 
Inhalative Toxicity
Key, Rydzynski and Swiercz, 1998, Aminopielik 600, rat, acute inhal., RL1 – LC50 >3080 mg/m³ air (females) and 3258 mg/m³ air (males) (based on an active ingredient content of 60.6% and doses of 5083 mg/m³ air (females) and 5377 mg/m³ air (males) used in the respective study)
Dermal toxicity
Key, Kita, 1997, Aminopielik 720, rat, acute dermal, RL2 - LD50 > 1452 mg/kg bw (based on an active ingredient content of 72.6% and a test concentration of 2000 mg/kg bw used in the respective study)
Kita, 1991, Aminopielik 600, rat, acute dermal, RL1 - LD50 = 4745 mg/kg bw (based on an active ingredient content of 51.6% and a test concentration of 6536 mg/kg bw used in the respective study)

Additional information

Studies conducted to examine the acute toxicity of dimethylammonium 2,4-dichlorophenoxyacetate were conducted according to OECD-guidelines No. 401 (Acute oral toxicity), 402 (Acute dermal toxicity) and 403 (Acute inhalation toxicity).

 

The test formulation was applied orally (gavage) to 5 female rats each in doses of 507, 659, 857, or 1114 mg/kg bw and the animals were observed for 14 consecutive days. Signs of intoxication were observed in rats of all dose groups. After exposure 0, 1, 3 and 5 rats died in the dose groups 507, 659, 857 and 1114 mg/kg bw, respectively. The mortality occurred during the first day (all 3 affected dose groups) and on day 2 and 4 (857 mg/kg bw dose group) after application. The oral LD50 value calculated was 764 mg/kg bw (Key, Kita, 1997, Aminopielik 720, rat, acute oral, RL1).

Another study was conducted analogously with doses of 474, 710, 1067 and 1600 mg/kg bw in male and female Wistar rats. In the highest dose group all rats died in the first two days after treatment. Two male and one female animal died until day 5 in the 1067 mg/kg bw group and one animal of the 710mg/kg bw dose group died on day 7. Shortly after the application of the test substance the animals of the highest dose group were dejected and less mobile, the hair was bristled. The same effects were observed in animals of the 1067 mg/kg bw dose group shortly before death. The oral LD50 value calculated was 994 mg/kg bw (Kita, 1991, Aminopielik 600, rat, acute oral, RL1)

 

The acute inhalative toxicity of the test formulation containing dimethylammonium 2,4-dichlorophenoxyacetate was examined in a study according to OECD 403. 5 Wistar rats of both sexes were exposed (whole body) to test atmospheres of 5377 mg/m³ air ± 1352 (females) and 5083 mg/m³ air ± 1422 (males), respectively. During the exposure and upon removal from the chamber, signs of laboured or irregular breathing and body convulsions were observed. 3 Male and 4 female animals survived the exposure to the test substance. The deaths of one male and one female animal was recorded on day 1 after exposure, another male animal died on day 2. The LC value was calculated to be above 5000mg/m³ air (Key, Rydzynski and Swiercz, 1998, Aminopielik 600, rat, acute inhal., RL1).

 

Two dermal studies were conducted according to OECD 402. 2000 mg/kg bw of the test formulation containing dimethylammonium 2,4-dichlorophenoxyacetate were applied to the dorsal area of the trunk of 5 Wistar rats of both sexes for 24 h under semiocclusive conditions. Most animals had a lower increase of body weight , but no deaths were observed during the observation period of 14 days. Therefore, the dermal LD50 value was above 2000 mg/kg bw (Key, Kita, 1997, Aminopielik 720, rat, acute dermal, RL2).

In another study, the dorsal area of the trunks of 5 female rats each were exposed to 2222, 3333, 5000 and 7500 mg/kg bw of the test formulation. Signs of intoxication like reduced mobility and bristled hair were observed in all dose groups except for the lowest dose. No mortality was noted in the lowest dose group. There were 1 , 3 and 5 deaths in the 3333 mg/kg bw, 5000 mg/kg bw, and 7000 mg/kg bw group, respectively. Deaths occurred on day 2 (one animal), 3 (5 animals), 4 (one animal), and 5 (one animal). The dermal LD50 value was calculated to be 6536 mg/kg bw (Kita, 1991, Aminopielik 600, rat, acute dermal, RL1).

 

Taken together, the available data on acute inhalative and dermal toxicity confirmed that dimethylammonium 2,4-dichlorophenoxyacetate is not acute toxic if applied via inhalative or dermal routes. LD 50 values resulting from oral application indicate a moderate acute toxicity under the conditions tested.

Justification for classification or non-classification

According to the DSD (67/548/EEC) criteria for classification and labelling of dangerous substances dimethylammonium 2,4-dichlorophenoxyacetate (CAS 2008-39-1) is classified harmful after acute oral application.

According to CLP (EC No. 1272/2008) criteria for classification and labelling of dangerous substances dimethylammonium 2,4-dichlorophenoxyacetate (CAS 2008-39-1) is classified to Category 4 after acute oral application.