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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

ErC50 (72 h) = 12.9 mg a.i./L (TWA, OECD 201, P. subcapitata)

NOErC (72 h) = 0.63 mg a.i./L (TWA, OECD 201, P. subcapitata)

Key value for chemical safety assessment

EC50/LC50 for freshwater algae:
12.9 mg/L
EC10, LC10 or NOEC for marine water algae:
0.63 mg/L

Additional information

There is one study available in which the short-term toxicity of (Z)-N-methyl-N-(1-oxo-9-octadecenyl)glycine, compound with 2,2',2''-nitrilotri(ethanol) (1:1) (CAS 17736-08-2) to aquatic algae was determined according to the OECD guideline 201 and GLP.

In a static test, exponential phase Pseudokirchneriella subcapitata at an initial cell density of 10^4 cells/mL was exposed to five WAFs with nominal loading rates of 1.0, 3.2, 10, 32 and 100 mg a.i./L for 72 h. Test item concentrations were analytically verified at the beginning (0 h), after 24 h and at the end of the test (72 h) by UPLC.

The measured initial concentrations (0 h) were 2.3, 2.7, 18, 26 and 79 mg a.i./L in the WAFs prepared at 1.0, 3.2, 10, 32 and 100 mg a.i./L, respectively. The three highest WAFs decreased to 61 – 66% of initial concentrations by the end of the test (72 h). The measured concentrations in the two lowest treatments decreased to levels below the limit of detection. Therefore, effect concentrations were expressed as Time Weighted Averages (TWA), assuming the calculated values 0.63, 0.83, 14, 16 and 60 mg a.i./L. It was shown that the decrease in test item concentration was not due to the presence of algae. From 48 h onwards, a floating layer was observed in the TWA concentrations of 14 mg a.i./L and higher, in which a layer of test item sticking to the wall of the test vessels was also observed after 72 h.

The test item significantly inhibited the growth rate and yield at TWA concentrations of 0.83 mg a.i./L and higher, resulting in an ErC50 (72 h) of 12.9 mg a.i./L and a NOErC (72 h) of 0.63 mg a.i./L (TWA).