N-ethyl-4-[[4-(ethylamino)-m-tolylphenyl][4-(ethylimino)-3-methylcyclohexa-2,5-dien-1-ylidene]methyl]-m-toluidine monoacetate

Short-term toxicity to aquatic invertebrates

Description of key information

In a 48-h acute toxicity study with Daphnia magna an EC50 of 0.0735 mg/L was determined (BASF SE, 2015).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.073 mg/L

Additional information

In the acute immobilisation test with Daphnia magna (STRAUS), the effects of the test item were determined according to OECD 202 (2004), equivalent to the Council Regulation (EC) No. 440/2008 Method C.2 (2008) (BASF SE, 2015).

The study was conducted under semi-static conditions over a period of 48 hours with a saturated solution with a nominal loading of 1000 µg/L of the test item and further four dilution levels in a geometric series with a separation factor of 2 (nominal loading rates of 6.25 to 50.0 %). A saturated solution with a nominal loading of 1000 µg/L of the test item was prepared with dilution water one day before the start of the exposure intervals (at -24 and 0 hours) and was used for testing and as stock solution for the preparation of all further tested dilution levels. Further dilution levels were prepared by diluting the saturated solution with dilution water. The tested solutions were visually clear throughout the exposure period with a concentration related light violet colour. Twenty daphnids were exposed to each concentration level and the control. The concentrations of the test item were analytically verified via LC-MS/MS. The measured concentrations of the test item at the start of the exposure intervals were within the range of 38.7 and 681 µg/L (0 hours) and 40.4 to 622 µg/L (24 hours) and reflect the dilution factor of 2. At the end of the exposure intervals (24 and 48 hours), the measured concentrations were within the range of 63 to 86 % of the initially measured concentrations. Since the measured test item concentrations did not remain within ± 20 % of the initially measured concentrations, the effect values are based on the geometric mean measured concentrations of the test item calculated to be: 34.8, 62.1, 134, 283, 525 µg/L. The water quality parameters (i.e. pH-value and dissolved oxygen concentration), measured at the start (0 and 24 h) and at the end of the exposure intervals (24 and 48 h), were within the acceptable limits. The validity criteria of the test guidelines were fulfilled.

Based on the geometric mean measured concentrations of the test item, the 48h-EC50 for Daphnia magna was 0.0735 mg/L (95 % confidence limits: 0.0685 - 0.0831 mg/L).