Reaction mass of ethoxylated N-oleyl-1,3-propanediamine, hydrofluorides of and ethoxylated N-palmityl-1,3-propanediamine, hydrofluorides of and ethoxylated N-stearyl-1,3-propanediamine, hydrofluorides of and olaflur

Toxicity to microorganisms

Description of key information

The EC50 to activated sludge was determined to be 240 mg/L (measured/geometric mean).

Key value for chemical safety assessment

EC50 for microorganisms:

240 mg/L

EC10 or NOEC for microorganisms:

32 mg/L

Additional information

Seven concentrations of the test item ranging from 10000 to 10 mg/L (nominal) were tested. Duration of the test was three hours. Activated sludge taken from a domestic sewage treatment plant and washed before usage, was used as inoculum. The dry matter was determined as 3.70 g suspended solids/L, giving a concentration of 1.48 g suspended solids/L in the test.

3,5-Dichlorophenole was used as positive control. Four concentrations were tested; an EC50 of 6.7 mg/L (95% confidence interval: 5.7 – 7.6 mg/L) was determined, which lies within the demanded range of 5 – 30 mg/L. All treatments, except for the lowest concentration (10 mg/L), showed inhibition of the respiration rate of the activated sludge. A dose-response-relationship could be established.

For the determination of the biological results, all inhibition values were evaluated. The mean of the O2-consumption of the controls was determined as 24.2 mg/L*h (standard deviation 1.1 mg/L*h). This means that the range of O2-consumption for the determination of the NOEC is 22.0 – 26.4 mg/L*h. Therefore, treatment 32 mg/L (O2-consumption rate 23.3 mg/L) was stated as NOEC.

All validity criteria were met. For the estimation of the EC50s of test item and positive control, the fits showed good statistical correspondence of the data with the dose-response-equation. Variation of the controls was below the recommended limit of 15%. Inhibition in the treatments 10000 – 1000 mg/L Olaflur was in a range of 100 – 85 %. In these treatments, pH was acidic (4.9 – 6.6). But in the treatment containing 316 mg/L test item, pH was 7.87, which is in the same range as in the controls. Nevertheless, 66 % inhibition was observed. Therefore, it is concluded that the inhibition values in the upper treatments are not (or at least not solely) caused by the low pH value. The result of the test can be considered valid. The EC50 to activated sludge was determined to be 240 mg/L.