Fatty acids, C16-18 and C18-unsatd., reaction products with diethylenetriamine, di-Me sulfate-quaternized

Toxicity to aquatic algae and cyanobacteria

Description of key information

The 72-hour LOEC for the growth rate was determined to be 1.0 mg/L (corresponding to a mean measured concentration of 21 μg/L) and the 72-hour NOEC for the growth rate was determined to be 0.32 mg/L (corresponding to a mean measured concentration of 7.6 μg/L) based on water accommodated fractions (WAFs).
In addition a long-term Coupled OECD Confirmatory test (5 weeks) for algae under flow through conditions for the closely related partially unsaturated IQAC, DMS quaternised is available. During the 35d exposure there was no change observed in the measured density of the algae cultures exposed to the test substance doted activated sludge unit. The 35d NOEC was determined to be > 100 μg/L, which is well in tune with the 72 h NOEC of the solvent-free oleic-acid based IQAC, DME quaternised. The Coupled OECD Confirmatory test is considered to be the better model for field conditions in surface waters at the outlet of sewage treatment plants and provide a more realistic scenario of exposure of algae.

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:

100 µg/L

Additional information

The 72 hour acute toxicity of Pseudokirchneriella subcapitata were exposed to partially unsaturated IQAC, DMS quaternised under static conditions in accordance to OECD Guideline 201 (2006). The 72-hour LOEC for the growth rate was determined to be 1.0 mg/L (corresponding to a mean measured concentration of 21 μg/L) and the 72-hour NOEC for the growth rate was determined to be 0.32 mg/L (corresponding to a mean measured concentration of 7.6 μg/L) based on water accommodated fractions (WAFs). The 72-hour LOEC for yield was determined to be 0.10 mg/L (corresponding to a mean measured concentration of 2.8 μg/L) and the 72- hour NOEC for yield was determined to be 0.032 mg/L (corresponding to a mean measured concentration of 0.52 μg/L) based on water accommodated fractions (WAFs).
The measured concentrations in the test media of the two lowest test item treatments with loading rates of 0.010 and 0.032 mg/L were <LOQbio (limit of quantification, 0.614 μg/L). The measured concentrations at the loading rates of 0.10, 0.32, 1.0, 3.2, 10 mg/L were 2.2, 6.2, 11, 14 and 22 μg/L, respectively. The biological results were related to the loading rates of the test item and to mean measured test item concentrations. There were no compound related phytotoxic effects.

 

In an acute test with algae according to DIN 38 412 Part 9 a similar result was observed. The EC50 was determined to be EC50 (72 h): ca. 1800 — 4500 μg/L act. ingr. (nominal). This value is based on the biomass and therefore not used for the assessment.

 

In a 5 weeks long-term toxicity study in a Coupled OECD Confirmatory Test the cultures of Scenedesmus subspicatus CHODAT (new name: Desmodesmus subspicatus) were exposed to the degradation products of the closely related partially unsaturated IQAC, DMS quaternised of an activated sludge unit at 24 °C. There was no change in the measured extinction of the algae cultures exposed to the surfactant doted activated sludge unit during the test period of 5 weeks. Only minor variation was observed. The mean extinction was 0.75 E. Visual inspection of the alga cultures showed optimal green coloured cultures, an indication of high active chlorophyll. Sedimentation of algae was not observed. The culture remained stabile over 5 weeks and no negative effects were observed. In comparison the control culture was somewhat labile, so that it could be concluded that the algae culture exposed to the degradation products was slightly promoted. During the test partially unsaturated IQAC, DMS quaternised, is eliminated in the model activated sludge unit by > 90%. The elimination is calculated to be 97.75% taking into account the inflow into the model activated sludge unit of the test substance with a concentration of 10 mg/l, the dilution of the effluent of the elimination unit in ratio 1:1.25 and the separately determined EC0=0.1 mg/l. Thus a NOEC of >100 μg/L is calculated. This toxicity study is classified as assignable, though only few data are reported.