N-(3-aminopropyl)-N- (C12-18 even numbered) alkyl-propane-1,3-diamine

Toxicity to aquatic algae and cyanobacteria

Description of key information

One toxicity test with algae has been performed with Triamine C12-18, C18-unsaturated. The 72 h EC10 and EC50 based on growth are respectively 137 and 223 μg a.i./L. The effects are expressed as nominal values because the test was performed with river water as it is intended to be used in an evaluation of the environmental risks based on the Bulk approach. 

Key value for chemical safety assessment

EC50 for freshwater algae:

223 µg/L

EC10 or NOEC for freshwater algae:

137 µg/L

Additional information

Triamine C12-18, C18-unsaturated (old CAS No. 91771-18-5, new CAS no 1219458-12-4) was found to inhibit the growth of the freshwater green alga Desmodesmus subspicatus after 72 h with the following effect values (nominal concentrations): The EC10-values with 95 % confidence intervals for inhibition of specific growth rate (ErC10) and yield (EyC10) after 72 h were 137 (127 – 149) and 99.1 (84.3 – 107) µg/L, respectively. The EC50-values with 95 % confidence intervals for inhibition of specific growth rate (ErC50) and yield (EyC50) after 72 h were 223 (215 – 229) and 141 (133 – 149) µg/L, respectively.

The test effect was observed to be reversible at all tested concentrations following 72 h exposure and 5 days of growth under test conditions.

The concentrations of Triamine C12-18, C18-unsaturated were analysed at the concentration levels 125 and 500 µg/L (prepared without algae) and the control at test start via LC-MS/MS analysis. The measured concentrations at test start were in the range of 86 – 88 % of the nominal values. At the end of the test Triamine C12-18, C18-unsaturated was analysed at concentration levels 125 and 500 µg/L (prepared without algae) and 125 µg/L (prepared with algae). All measured concentrations were determined to be < LOQ. 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 decrease was attributed to additional sorption to suspended matter and DOC due to thermodynamically driven redistribution of the sorbed fraction. No adsorption (<LOQ) of the test item to glassware was observed. The algae were therefore fully exposed to the bulk test substance concentration. Therefore all effect values are given based on nominal concentrations of the test item.