2-[2-[4-(dimethylamino)phenyl]vinyl]-1,3,3-trimethyl-3H-indolium acetate

Short-term toxicity to aquatic invertebrates

Description of key information

After 48 hours of exposure the EC50 was determined to be 0.0354 mg/L according to OECD 202 (2004).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.035 mg/L

Additional information

 

In a semi-static key immobilization test (BASF SE, 50E0476/14X589, 2016) Daphnia magna were exposed to the test item for 48 hours according to OECD 202 (2004) under GLP conditions. The test was performed in the test item concentrations of 0.2, 0.1, 0.05, 0.025, 0.0125, 0.00625 mg/L (what corresponds to 0.1118, 0.0559, 0.02795, 0.01398, 0.006988, 0.003494 mg/L of the main ingredient) plus the control. Four replicates of each treatment with five Daphnia magna per replicate were used. All treatments were renewed after 24 hours of exposure. Daphnia magna were observed for immobilization after 24 and 48 hours of exposure. The test item is miscible with water at room temperature, therefore a stock solution was prepared. The appropriate amount of the test item was weighed in a glass beaker and transferred by multiple washing with Elendt M7 medium into a glass flask and filled up to appropriate volume of the with Elendt M7 medium. The test item concentration of 10 mg/L was visually homogeneous (without any visible undissolved particles). Lower test item concentrations were prepared by sequential dilutions with Elendt M7 medium in a ratio 1:9 (v/v) (i.e. 50 mL of higher test item concentration was mixed with 450 mL of Elendt M7 medium). The procedure was the same at exposure initiation and at renewal. The content of the main ingredient in the test item concentrations were determined with a validated spectrophotometric method. The content of the main ingredient in the test item concentration of 0.05 mg/L is below the LoQ value. The content of the main ingredient in the test item concentrations of 0.025, 0.0125, 0.00625 mg/L is below the LoD value. In the fresh samples collected at exposure initiation in the test item concentrations of 0.025, 0.0125, 0.00625 mg/L the determined content of the main ingredient was below LoD value (LoD = 0.02 mg/L). In the fresh sample collected at exposure initiation in the test item concentration of 0.05 mg/L the determined content of the main ingredient was below LoQ value (LoQ = 0.05 mg/L). In the fresh samples collected at exposure initiation and at renewal in the test item concentrations of 0.2 and 0.1 mg/L the determined content of the main ingredient was in the range of 98.03 – 109.12% of nominal concentration. Therefore, the results confirm correct preparation of the test item concentrations.

The test item concentrations were stable under test conditions. In the old samples collected at renewal and at exposure termination the determined content of the main ingredient was in the range of 100.18 – 108.41% of nominal concentration. The test item concentrations were stable under test conditions and the endpoint values were determined based on the nominal test item concentrations. After 48 hours of exposure the EC50 was determined to be 0.0354 mg/L.

In addition, the percentage of immobilization of Daphnia magna in the control was 0% (criterion: not more than 10%) and the dissolved oxygen concentrations in the test vessels were within the range of 8.8 – 9.3 mg/L (criterion: not less than 3 mg/L), therefore in the definitive test the validity criteria were met according to OECD Guideline No. 202 (2004).

A supporting Non-GLP study (BASF SE, 1/1196/2/88 -1196/88, 1989) was also performed with the test substance according to the EU Method C.2. (Acute Toxicity to Daphnia Magna) under static conditions.The 48 h acute toxicity of the test item to Daphnia magna was studied under static conditions according to EU method C.2. Daphnids were exposed to the test item (CAS 71598 -17 -9) at nominal concentrations of 7.812, 15.6, 31.3, 62.5, 125 and 250 µg/L. The test item was applied in a mixture consisting of 20 % active substance. No analytical monitoring was done. Mortality effects were observed during the study from a concentration level of 62.5 µg/L onwards.The 48 h EC50 was determined to be 73.53 µg/L.