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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The ErC50 of 414 µg/L and the ErC10 of 121 µg/L were determined in a test according to OECD TG 201 (GLP)  with Quaternary ammonium compounds, C12-18-alkylbis(hydroxyethyl)methyl, chlorides using river water. Effect concentrations are based on active ingredient.

Key value for chemical safety assessment

EC50 for freshwater algae:
413.5 µg/L
EC10 or NOEC for freshwater algae:
121 µg/L

Additional information

Three algae toxicity studies are available for various Quaternary ammonium compounds, alkylbis(hydroxyethyl)methyl, chlorides. The key study is based on the same substance as registered (reliability 1). The two supporting studies are performed with quaternary ammonium compound C12 and quaternary ammonium compound C14 (both reliability 4, because no GLP, no certificates of analysis of the technical products were available, and nominal concentrations based on test material). All studies were performed according to OECD 201. The study performed with the C12 -18 will be used as key study. This study was done with river water, rendering the test results suitable for the use of the bulk water approach that will be used for the chemical safety assessment. The ErC50s for the key study, for the study performed with C12 and the study performed with C 14 were 416 µg/L, 380 µg/L and 160 µg/L respectively. The EC10 of the key study was determined to be 122 µg/L (test mat).

In the key study the toxicity to Pseudokirchneriella subcapitata was determined according to OECD TG 201 (Scheerbaum, 2010). The concentrations of Quaternary ammonium compounds, C12 -18 -alkylbis(hydroxyethyl)methyl, chlorides were analysed and the measured concentrations at test start were in the range of 95 – 118 % of the nominal values. At the end of the test the levels ranged from the LOQ to 90 % of the nominal values. Biodegradation as possible reason for this decrease is very unlikely considering the short time frame, also the river water was frozen before use to minimize the microbial activity. The observed decrease is attributed to additional sorption to suspended matter and DOC due to thermodynamically driven redistribution of the sorbed fraction. Negligible adsorption (1% of nominal) of the test item to glassware was observed. Therefore all effect values are given based on nominal concentrations of the test item.

After 72 h, algae were transferred from the nominal concentrations of 200 – 640 µg/L and the control to fresh untreated medium and allowed to grow for further 4 d under test conditions. The test item effect was observed to be reversible at these concentrations. Therefore, there is potential for recovery following exposure up to 640 µg/L (highest test concentration).