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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

72 h ErC50 = 14.7 mg a.i./L (95% c.l. 12.4 - 17.5 mg a.i./L)
72 h ErC10 = 4.42 mg a.i./L (95% c.l.3.70 - 5.18 mg a.i./L)
72 h NOEC = 1.3 mg a.i./L
(OECD TG 201; Desmodesmus subspicatus; static, natural river water containing 2.91 mg/L TOC (2.84 mg/L DOC); RL1; GLP)

Key value for chemical safety assessment

EC50 for freshwater algae:
14.7 mg/L
EC10 or NOEC for freshwater algae:
4.42 mg/L

Additional information

In a 72 hour toxicity study according to OECD Guideline 201 (2011), the cultures of Desmodesmus subspicatus  CHODAT SAG 86.81 were exposed to Undecylenamidopropyl Betaine at nominal concentrations of 0 (control), 3.05, 6.10, 12.2, 24.4, 48.8 mg a.i./L in natural river water, corresponding to geom. mean measured concentrations of 0 (control), 1.3, 4.58, 10.0, 22.9, 47.3 mg a.i./L under static conditions.

All test concentrations and the control were analytically verified by LC-MS/MS analysis at the start of the exposure (0 hours), 24, 48 hours and the end of the exposure (72 hours).

Microscopic evaluation of the cells at start and the end of the incubation period revealed no morphological abnormalities.

The test item solutions were visually clear throughout the exposure phase of 72 hours. Concentration related, slight foaming was observed during the whole exposure phase.

The measured concentrations of the test item at the start of the exposure were in the range of 104 to 107% of the nominal values. At the end of the exposure, the measured concentrations of the test item were in the range of 17 to 90% of the nominal values. Therefore, all calculation results are based on the geometric mean measured concentrations.

The NOEC, EC10 and EC50 of Undecylenamidopropyl Betaine based on growth rate were 1.3 mg a.i./L, 4.42 mg a.i./L (95% c.l.3.70 - 5.18 mg a.i./L) and 14.7 mg a.i./L (95% c.l. 12.4 - 17.5 mg a.i./L), respectively.

The NOEC, EC10 and EC50 of Undecylenamidopropyl Betaine based on yield were 1.3 mg a.i./L, 2.85 mg a.i./L (95% c.l.2.09 - 3.57 mg a.i./L) and 4.85 mg a.i./L (95% c.l.4.35 - 5.47 mg a.i./L), respectively.